Startseite Lebenswissenschaften Meta-analysis of the effect garlic (Allium sativum) on productive performance, egg quality, and lipid profiles in laying quails
Artikel Open Access

Meta-analysis of the effect garlic (Allium sativum) on productive performance, egg quality, and lipid profiles in laying quails

  • Christian Anayo Mbajiorgu , Ifeanyi Princewill Ogbuewu EMAIL logo und Monnye Mabelebele
Veröffentlicht/Copyright: 3. September 2025
Artikel downloaden (PDF)
Open Agriculture
Aus der Zeitschrift Open Agriculture Band 10 Heft 1

Abstract

The objective of the investigation is to use a meta-analysis method to resolve uncertainty, identify research gaps, and create new insights using published data on the effect of garlic intervention on lipid profiles, productive traits, and egg quality indices in laying quails. Twenty studies on the topic were identified based on a systematic search conducted on four bibliographic databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Statistical analysis was performed in OpenMEE and STATA/MP 14.0 software. Results were expressed as raw mean differences at 95% confidence intervals. Pooled estimation showed that garlic increased egg production (EP) and serum high-density lipoprotein by 0.38% (p = 0.034) and 1.18 mg/dl (p < 0.001), respectively, in laying quails with evidence of significant heterogeneity. In contrast, feed conversion ratio, concentrations of serum total cholesterol, triglycerides, low-density lipoprotein, and egg cholesterol were reduced by 1.09 mg/dl (p < 0.001), 0.72 mg/day (p = 0.003), 1.55 mg/dl (p < 0.001), and 2.04 mg/g yolk (p < 0.001), respectively. Subgroup analysis results revealed that laying quails that received <1.0% garlic had better EP than those that received garlic at 1.0, 1.5, and >2.0%. In contrast, laying quails that received 1.0% garlic had significantly lower triglycerides than those offered >2.0% garlic. Meta-regression results indicated that covariates explained most of the sources of significant heterogeneity. The findings of the current meta-analysis revealed the potential of garlic intervention to improve lipid profiles, productive traits, and egg quality indices in laying quails.

Keywords: blood characteristics; feed conversion ratio; feed intake; meta-regression; yolk cholesterol

1 Introduction

Quail (Coturnix coturnix) has gained recognition as a quality protein source and may be utilized to solve the challenge of food security in developing nations [1]. Quail meat is endowed with zinc, calcium, and phosphorus, vitamins, proteins, oleic, stearic acids linoleic, and palmitic and is lower in cholesterol content than chicken [2,3]. Furthermore, the egg is abundant in fatty acids (α-linolenic and linoleic), minerals (nitrogen, magnesium, phosphorus, potassium, iron, copper, calcium, zinc, and sodium), vitamins (A, E, D, and B6), proteins (characterized by the high level of valine, leucine, and lysine needed for normal body function), and bioactive components such as cystatin, ovomucoid, and lysozyme shown to have medicinal properties [4,5]. Quail eggs also contain serine, aspartic acid, and alanine which are vital for human health [6,7]. Despite the good attributes of quail meat and eggs, quail farmers in developing countries face problems of high feed costs due to the escalating cost of imported conventional feedstuffs, especially protein and energy concentrates, arising from high foreign exchange rates. Hence, it is important to enhance quail productivity using tropical medicinal herbs that are abundant and rich in nutrients and beneficial phytochemicals. One such tropical medicinal herb with the capacity to improve feed efficiency and nutrient assimilation in quails is garlic (Allium sativum).

Garlic is a perennial plant of the Amaryllis family (Amaryllidaceae), grown for its flavorful bulbs. It is also used as a spice in human food preparation as well as in the preparation of folklore medicine. Studies suggest that garlic possesses a myriad of beneficial pharmacological properties, viz., antioxidants, anti-inflammatory, antimicrobial, and hypocholesterolemic in animals [8,9]. These functions were due to alliin, ajoene, and allicin present in garlic [10,11]. Due to its several bioactive substances, garlic and its products are included in livestock and poultry diets in smaller quantities to stimulate the release of gastric juice and endogenous digestive enzymes, modulate intestinal microbiota composition in favor of the growth of beneficial microbes [8] and feed efficiency [11]. Additionally, the antioxidant components in garlic, especially allicin, can enhance egg production (EP) and quality in laying quails by preventing oxidative stress [12]. Allicin and its derivatives can impact lipid metabolism in laying quails via the following mechanisms: (i) stimulate adenosine monophosphate-activated protein kinase to increase thermogenesis and reduce fat accumulation [13], (ii) downregulation of genes involved lipogenesis [14], and (iii) enhance bile acid excretion and suppress the activity of main enzymes involved in cholesterol biosynthesis [15].

Abdulkareem [16] reported that inclusion of 0.5 and 1.0% garlic in the diet of 30-week-old quails reduced serum total cholesterol (TC), very low-density lipoprotein, low-density lipoprotein (LDL), uric acid, and feed intake (FI) compared to the quails in the control group that received rations without garlic. The author also discovered that quails offered garlic at 0.5 and 1% performed better than the control quails in terms of EP, egg weight (EW), jejunal, and ileal villus height-to-crypt depth ratio. However, garlic inclusion at 0.5 and 1.0% did not influence shell thickness (ST), yolk height, Haugh unit (HU), and albumin height. In a similar study, Olayinka et al. [17] showed that garlic bulb supplementation at 0.025. 0.05, and 0.075% for 16 weeks reduced feed conversion ratio (FCR) and increased FI, EP, EW, yolk index, and shell characteristics in 6-week-old quails. Olayinka et al. [17] also found that HU was not affected in quails fed garlic bulbs at 0.25. 0.50, and 0.75% for 16 weeks. Likewise, Yalcın et al. [18] noticed that supplementation of garlic powder (0, 0.5, and 1.0%) in the diet of quails increased EW and HU but had no influence on EP, FCR, and ST. These findings disagreed with Olayinka et al. [17] and Abdulkareem [16], who reported that garlic increased EP in quails. Behnamifar et al. [19] reported similar FI, FCR, EP, EW, egg mass (EM), HU, and shell quality (ST and shell weight [SW]) in quails administered 0 and 0.1% garlic extract. Similarly, Khan et al. [20] noticed that FI, FCR, EW, and EM were not affected in laying quails offered 0, 0.2, 0.6, and 0.8% garlic bulb powder, which contrasted the results of other investigators [16,17]. These disparities could be related to differences in study designs, analytical methods, parts of garlic used, presentation form (extract, oil, or powder), quantity of garlic added to the feed, garlic bioactive compounds, and other variables that can influence EP and quality in quails.

The use of meta-analysis to aggregate results of published studies with conflicting findings to increase statistical power, resolve inconsistent findings, create new insight, and identify knowledge gaps has, in recent times, gained recognition in animal nutrition [9,21,22]. Presently, there is no published meta-analysis on the effect of garlic on productivity, health status, and egg quality in quails. Given the objective of the modern quail industry to achieve high EP and feed utilization. Therefore, the study was designed to determine the meta-analysis of garlic on productive traits, egg quality, and serum lipid profiles of laying quails.

2 Materials and methods

2.1 Literature search techniques and study selection criteria

Four search engines (Web of Science, PubMed, Scopus, and Google Scholar) were methodically searched for publications that evaluated the influence of garlic on performance and egg quality indices of laying quails according to the method described by Page et al. [23]. The search used the keywords: garlic, A. sativum, FI, feed efficiency, FCR, egg-to-feed ratio, EP, hen day EP, and egg quality in connection with quails using the Boolean operators.

Publications were selected based on the PICO format, where the population (P) is laying quails, intervention (I) is garlic, comparators (C) are quails that did not receive garlic, and outcomes (O) are FI, FCR, EP, EW, EM, HU, SW, ST, EC, serum TC, TG, high-density lipoprotein (HDL), and LDL. Identified studies were imported into Zotero (Version 7.0), and duplicated studies were identified and excluded. Inclusion criteria were information on (i) studies that evaluated the effect of garlic on at least one of the measured outcomes in laying quails; (ii) experimental diets did not contain antibiotics or mixed garlic with other phytogenic feed additives (PFAs); (iii) studies have a control treatment without garlic intervention; (iv) quails were randomly allotted to each treatment; and (v) publication provided data on garlic, mean of measured outcome on each treatment with their corresponding standard deviation or standard error. Exclusion criteria were information on (i) studies not conducted in laying quails; (ii) studies that report at least one of the measured outcomes in laying quails; and (iii) studies that included antibiotics in the diet or mixed garlic with other PFAs. The systematic search yielded 882 publications, of which 706 were not used for being duplicated across the four bibliographic databases. Out of the 156 studies remaining, 136 did not meet any of the predefined inclusion criteria. In total, 20 publications met the inclusion criteria and were used for the meta-analysis shown in Figure 1 and Table 1. The included publications were independently assessed for eligibility criteria by all the authors, and the controversy on whether to include or exclude a publication was settled by consensus.

Figure 1 The flow chart of the study selection process using the PRISMA guidelines.
Figure 1

The flow chart of the study selection process using the PRISMA guidelines.

Table 1

Characteristics of included studies in the meta-analysis

References Country Continent Covariates Response variables
PF1 QA2 DI3 DL4
Yalcın et al. [18] Turkey Europe Powder 9 21 0, 0.5, 1.0 FI, FCR, EP, EW, HU, ST, EC, TC
Canogullari et al. [31] Turkey Europe Powder 10 12 0, 1.0, 2.0, 3.0, 4.0 FI, FCR, EP, EW, HU, SW, ST, EC, TC
Zeweil et al. [32] Egypt Africa Powder 18 12 0, 0.75, 1.5 FI, FCR, EP, EW, SW, ST, EC
Omonoma and Jarikre [33] Nigeria Africa Powder 16 10 0, 0.1, 0.2, 0.4 TC, TG, HDL
Abdou and Rashed [34] Egypt Africa Powder 1 10 0, 3.0 FI, FCR, EP, EW, EM, EC, TC, HDL, LDL
Udeh et al. [35] Nigeria Africa Powder 8 5 0, 0.5, 1, 1.5 HU, EW, SW, ST, TC, TG, HDL, LDL
Swain et al. [36] India Asia Powder 1 5 0, 1.0 TC, TG
Udeh et al. [37] Nigeria Africa Powder 1 5 0.5, 1.0, 1.5 TC, TG, HDL, LDL
Behnamifar et al. [19] Iran Asia Extract 10 8 0, 1.0 FI, EP, EW, EM, HU, EC, TC, TG, HDL, SW, ST
Bhavani et al. [38] India Asia Powder 6 5 0, 0.5, 1, 1.5, 2 TC, TG, HDL, LDL
Mohammed et al. [39] Iraq Asia Powder 5 2 0, 1.0, 1.5 FI, FCR, EP, EM, EW, HU, ST
Ismael and Ameen [40] Iraq Asia Powder 5 7 0, 2.0, 4.0 FI, FCR, EP, EW, EM, HU, SW, ST, TC, TG, HDL
Olayinka et al. [17] Nigeria Africa Powder 6 16 0, 0.25, 0.5, 0.75 FI, FCR, EP, EW, EM, HU, SW, ST
Mohammed et al. [41] Iraq Asia Powder 6 6 0, 3.0 TC, TG
Nurhayati et al. [42] Indonesia Asia Fresh 3 8 0, 3.0 FI, FCR, EP, EW, TC, HDL, LDL
Taleb et al. [24] Egypt Africa Powder 1 5 0, 0.5 TC, TG, HDL, LDL
Abdulkareem [16] Iraq Asia Powder 30 10 0, 0.5 FI, FCR, EP, EW, EM, HU, ST, TC, TG, HDL, LDL
Hidayatik et al. [43] Indonesia Asia Extract 6 4 0, 1.0, 2.0, 4.0 TC, TG
Kour et al. [44] India Asia Powder 6 5 0, 1.0 EW, HU, EC, ST
Raya et al. [45] Egypt Africa Powder 2 6 0, 1.0 TC, TG, HDL, LDL

FI – feed intake; FCR: feed conversion ratio; EP – egg production; EW – egg weight; EM – egg mass, HU – haugh unit; SW – shell weight; ST – shell thickness; EC – egg cholesterol; TC – total cholesterol; TG – triglycerides; HDL – high-density lipoprotein; LDL – low density lipoprotein. 1 – presentation form (PF) of garlic; 2 – quail age (QA) in weeks; 3 – duration of intervention (DI) of garlic in weeks; 4 – dose level (DL) of garlic in percentage (%).

2.2 Database development and statistical analysis

A database of the 20 publications that met the inclusion criteria is displayed in Table 1. The WebplotDigitizer Version 4.5 [24] was used to extract data presented as graphs. The covariates considered to influence the pooled results were presentation form of garlic (powder, fresh, and extract), the dose level of garlic (0.1–4.0%: categorized into <1, 1.5, 2.0, and >2.0%), duration of garlic intervention (≤10 vs 10 weeks), and quail age (1–30 weeks). OpenMEE software [25] and STATA/MP 14.0 software were used for the analysis. A random-effects model was adopted, and effect sizes were expressed as raw mean difference (RMD) at 95% confidence interval (CI) for each publication. Heterogeneity was determined based on standard methods [26,27]. Subgroup and meta-regression analyses were done on selected covariates deemed a priori to account for the sources of heterogeneity in this meta-analysis. Meta-regression and subgroup analysis were not executed on measured outcomes with <10 publications because of low statistical power [28,29]. Subgroup analysis was also not conducted for the stratum with <3 comparisons because of low sample size [30]. The subgroup effect of age as a covariate on laying quail productivity was not analyzed in this study, as most of the studies for the meta-analysis used quails that are less than 11 weeks of age. Likewise, the effect of the presentation form and part of garlic used were not tested as covariates due to low sample size, as most studies used in the meta-analysis used garlic in its dry form. Publication bias was assessed in this meta-analysis using Egger’s regression asymmetry test [46]. The statistical model used for the meta-regression analysis was Y ij = β 0 + β 1 X ij + e ij , where Y ij = dependent variable, β 0 = constant/intercept, β 1 = regression coefficient, and X ij = covariates (or predictors), and e ij = residual error. All analyses were considered significant at a 5% probability level.

3 Results

3.1 Study characteristics

The study selection process, as displayed in Figure 1, revealed that 882 studies were retrieved from the search conducted on four bibliographic search engines. After removing the duplicated studies (n = 706), 156 studies were left. Out of the 156 studies, 20 full-text articles satisfied the inclusion criteria and were used for the meta-analysis. The characteristics of the 20 published studies are shown in Table 1.

3.2 Laying performance

Table 2 presents the productive and egg quality parameters of laying quails on dietary garlic supplementation. Results suggest that garlic supplementation reduced FCR by 0.44 (p < 0.027), without affecting FI (p = 0.885), EW (p = 0.800), EM (p = 0.085), HU (p = 0.080), ST (p = 0.349), and SW (p = 0.678) in laying quails taking cognizance of significant heterogeneity (I 2 = 78–95%). Conversely, garlic supplementation increased EP in laying quails by 0.83% (p = 0.034). Egger’s test results indicated the absence of publication bias in productive parameters and egg quality. Subgroup effects of covariates on productive and egg quality parameters in laying quails are summarized in Table 3. The subgroup results revealed that FI, FCR, EW, and ST were not affected by dose level and duration of garlic intervention in laying quails. In contrast, laying quails that received <1.0% garlic had their EP increased by 0.88% compared to those quails that received 1.0, 1.5, and >2.0% garlic. The subgroup results also revealed that selected covariates did not solve the problem of significant heterogeneity in this study.

Table 2

Productive indices of laying quails on garlic intervention

Parameters Random-effects model Heterogeneity ET
n RMD 95% CI p value I 2 % p value p value
FI (g) 20 −0.02 −0.24, 0.20 0.885 78 <0.001 0.085
FCR 20 −0.44 −0.83, −0.05 0.027 93 <0.001 0.612
EP (%) 20 0.83 0.03, 0.72 0.034 91 <0.001 0.321
EW (g) 24 0.03 −0.21, 0.27 0.800 85 <0.001 0.054
EM (g) 15 0.51 −0.07, 1.08 0.085 95 <0.001 0.897
HU 20 −0.09 −0.19, 0.01 0.080 0 0.999 0.561
ST (mm) 22 0.11 −0.12, 0.34 0.349 82 <0.001 0.068
SW (g) 14 0.06 −0.22, 0.34 0.678 78 <0.001 0.912

RMD – raw mean difference; n – number of comparisons; CI – confidence interval; I 2 – Inconsistency index; FCR – feed conversion ratio; ET – Egger’s test.

Table 3

Impact of covariates on FI, FCR, EP, EW, and ST in laying quails on garlic intervention

Parameters Covariates RMD 95% CI p value Heterogeneity
I 2 (%) p value
FI (g) Dose level (%)
<1.0 0.33 −0.03, 0.68 0.072 82 <0.001
1.0 −0.02 −0.23, 0.19 0.836 4 0.389
1.5 −0.15 −0.47, 0.17 0.369 0 0.431
>2.0 −0.21 −0.78, 0.36 0.468 79 0.002
Duration (weeks)
≤10 −0.25 −0.58, 0.08 0.140 68 <0.001
>10 0.18 −0.08, 0.44 0.166 78 <0.001
FCR Dose level (%)
<1.0 −0.48 −1.16, 0.21 0.172 95 <0.001
1.0 −0.03 −0.42, 0.36 0.884 66 0.019
1.5 0.01 −0.33, 0.35 0.964 10 0.330
>2.0 −1.99 −4.16, 0.18 0.073 98 <0.001
Duration (weeks)
≤10 −0.91 −1.82, 0.00 0.050 95 <0.001
>10 −0.19 −0.60, 0.22 0.355 91 <0.001
EP (%) Dose level (%)
<1.0 0.88 0.31, 1.44 0.002 92 <0.001
1.0 −0.04 −0.28, 0.21 0.767 20 0.285
1.5 −0.14 −0.46, 0.18 0.388 0 0.377
>2.0 0.84 −0.44, 2.12 0.199 95 <0.001
Duration (weeks)
≤10 0.28 −0.32, 0.88 0.357 90 <0.001
>10 0.46 0.01, 0.91 0.044 93 <0.001
EW (g) Dose level (%)
<1.0 0.01 −0.31, 0.33 0.951 80 <0.001
1.0 −0.10 −0.49, 0.30 0.627 78 <0.001
1.5 −0.30 −0.92, 0.32 0.340 79 0.002
>2.0 0.63 −0.65,1.91 0.334 95 <0.001
Duration (weeks)
≤10 −0.03 −0.51, 0.46 0.915 90 <0.001
>10 0.10 −0.08, 0.28 0.294 55 <0.018
ST (mm) Dose level (%)
<1.0 0.13 −0.36, 0.61 0.608 91 <0.001
1.0 0.16 −0.24, 0.56 0.441 78 <0.001
1.5 0.33 −0.16, 0.82 0.183 67 0.028
Duration (weeks)
≤10 0.20 −0.17, 0.57 0.297 79 <0.001
>10 0.02 −0.28, 0.32 0.907 84 <0.001

3.3 Lipid characteristics

Table 4 shows the effects of garlic supplementation on serum lipid profile and EC in laying quails. Results showed garlic intervention reduced EC and serum TC, TG, and LDL by 2.04 mg/g yolk (p < 0.001), 1.09 mg/dl (p < 0.001), 0.72 mg/dl (p < 0.001), and 1.55 mg/dl (p < 0.001), respectively. In contrast, garlic increased the concentration of serum HDL in laying quails by 1.18 mg/dl (p < 0.001). The Egger’s test results suggested an absence of significant publication bias in serum lipid profiles. Subgroup effects of covariates on serum lipid profiles of laying quails on dietary garlic supplementation, as summarized in Table 5, indicated that serum TC was not affected by dose level and duration of garlic intervention. Likewise, serum HDL in laying quails was not affected by the quantity of garlic added to the diet. In contrast, results showed that laying quails fed 1.0% garlic had significantly lower serum TG than those fed garlic at >2.0% garlic. Laying quails offered garlic at 1.0% had similar serum TG values to quails fed garlic at <1.0, 1.5, and 2.0%. The subgroup effects of the duration of garlic intervention on serum TG and HDL were not analyzed in this meta-analysis, as the studies utilized for this analysis administered garlic for ≤10 weeks. Results also suggested that subgroup analysis by covariates did not solve the issue of significant heterogeneity in this meta-analysis.

Table 4

Serum lipid profiles and egg cholesterol content of quails on garlic intervention

Parameters Random-effects model Heterogeneity ET
n RMD 95% CI p value I 2 (%) p value p value
TC (mg/dl) 36 −1.09 −1.49, −0.68 <0.001 95 <0.001 0.350
Triglycerides (mg/dl) 29 −0.72 −1.20, −0.24 0.003 95 <0.001 0.141
HDL (mg/dl) 26 1.18 0.70, 1.67 <0.001 94 <0.001 0.201
LDL (mg/dl) 19 −1.55 −1.99, −1.11 <0.001 92 <0.001 0.184
EC (mg/g yolk) 10 −2.04 −2.67, −1.41 <0.001 93 <0.001 0.298

RMD – raw mean difference; n – number of comparisons; CI – confidence interval; I 2 – inconsistency index; EC – egg cholesterol; ET – Egger’s test.

Table 5

Impact of covariates serum TC, TG, and HDL in quails on garlic intervention

Parameters Covariates RMD 95% CI p value Heterogeneity
I 2 (%) p value
TC (mg/dl) Dose level (%)
<1.0 −0.54 −1.33, 0.25 0.179 95 <0.001
1.0 −1.37 −2.16, −0.58 <0.001 95 <0.001
1.5 −0.66 −2.22, 0.91 0.411 97 <0.001
2.0 −1.85 −2.57, −1.13 <0.001 84 <0.001
>2.0 −1.06 −1.97, −0.16 0.022 95 <0.001
Duration (weeks)
≤10 −0.87 −1.30, −0.45 <0.001 94 <0.001
>10 −2.36 −3.31, −1.40 <0.001 95 <0.001
Triglycerides (mg/dl) Dose level (%)
<1.0 0.43 −0.53, 1.38 0.379 94 <0.001
1.0 −2.01 −2.84, −1.18 <0.001 94 <0.001
1.5 −1.04 −2.31, 0.24 0.111 95 <0.001
2.0 −1.44 −2.03, −0.85 <0.001 72 0.012
>2.0 0.47 −0.50, 1.44 0.344 93 <0.001
HDL (mg/dl) Dose level (%)
<1.0 0.51 −0.18, 1.20 0.150 90 <0.001
1.0 1.21 0.47, 1.94 0.001 89 <0.001
1.5 1.76 0.07, 3.45 0.042 97 <0.001
2.0 2.64 0.74, 4.47 0.006 95 <0.001
>2.0 1.31 −0.25, 2.86 0.099 97 <0.001

3.4 Meta-regression analysis

Meta-regression results, as summarized in Table 6, found a significant relationship between quail age and FI (Q B = −0.04; p < 0.001; R 2 = 77%) and serum HDL (Q B = 2.78; p < 0.001; R 2 = 75%). Likewise, the duration of garlic intervention was significantly related to FI (Q B = 0.18; p = 0.042; R 2 = 21%) and serum HDL (Q B = 1.24; p < 0.001; R 2 = 52%). Results show age as a covariate was significantly related to FCR (Q B = 0.04; p < 0.001; R 2 = 88%), EP (Q B = −0.02; p < 0.001; R 2 = 93%), and EW (Q B = −0.34; p < 0.001; R 2 = 61%). Similarly, serum TC exhibited significant relationships with the duration of garlic intervention (Q B = −2.41; p = 0.021; R 2 = 11%). Additionally, serum TG was related to quail age (Q B = −2.73; p = 0.018; R 2 = 27%) and dose level (Q B = 0.48; p = 0.006; R 2 = 29%).

Table 6

Relationships between covariates and measured outcomes

Variables Covariates Q B Q M p value R 2 (%)
FI Quail age −0.04 31.7 4.63 × 10−5 77
Dose level −0.02 7.51 0.111 20
Duration 0.18 4.15 0.042 21
FCR Quail age 0.04 81.1 8.33 × 10−15 88
Dose level −0.01 3.16 0.531 0
Duration −0.19 0.95 0.330 0
EP Quail age −0.02 106.0 0.002 93
Dose level −0.02 9.13 0.058 24
Duration 0.46 0.21 0.664 0
EW Quail age −0.34 32.9 6.42 × 10−5 61
Dose level −0.11 3.89 0.421 0
Duration 0.10 0.20 0.659 0
ST Quail age 0.13 8.64 0.195 10
Dose level 0.16 1.79 0.775 0
Duration 0.02 0.54 0.463 0
TC Quail age −1.95 5.74 0.765 0
Dose level −1.37 3.38 0.497 0
Duration −2.41 5.34 0.021 11
Triglycerides Quail age −2.73 18.5 0.018 27
Dose level 0.48 14.5 0.006 29
Duration −0.55 3.50 0.624 0
HDL Quail age 2.78 65.6 1.1 × 10−10 75
Dose level 0.52 3.06 0.548 0
Duration 1.24 29.3 6.72 × 10−6 52

Q M – coefficient of moderators; Q B – regression coefficient (or beta); R 2 – amount of heterogeneity explained by the covariates.

4 Discussion

Garlic is high in essential nutrients (protein, minerals, fatty acids, vitamins) and bioactive compounds (i.e., allicin, alliin, ajoenes, steroid saponins, polyphenols, flavonoids, and organo-selenium) demonstrated to have numerous health benefits [8,47]. However, the response of laying quails to garlic intervention is not clear across studies. Therefore, this meta-analysis assessed the impact of garlic intervention on productive parameters, egg quality, and lipid profiles of laying quails. The results revealed that garlic improved FCR and EP in laying quails at a comparable FI with those on the control treatment. This shows that less feed is needed to produce a unit egg, suggesting higher EP efficiency and increased profitability. The large magnitude of effect size for EP implies that the difference between the quail fed diet with and without garlic is strong. This indicates that for enhanced EP, quail farmers should add garlic to the quail diet at <1.0%. The significantly low FCR recorded for quails on garlic intervention in this study can be ascribed to antimicrobial properties of garlic’s bioactive compounds leading to the reduction in bacterial competition with the host (quails) for available nutrients in the gastrointestinal tract and a decline in the level of toxins produced by pathogenic bacteria due to a decline in bacterial fermentation, leading to improvement in energy and protein digestion and utilization, thereby increasing EP and quality. Olayinka et al. [17] found improved FCR and EP in laying quails fed garlic at 0.25 and 0.5%, which is consistent with the findings of the current meta-analysis. In a similar study, Canogullari et al. [31] found enhanced FCR and EP in laying quails fed a diet supplemented with garlic at 1%. However, this contrasted with Behnamifar et al. [19], who noticed that the administration of garlic bulb extracts to laying quails did not improve FCR and EP. The disparity in FCR and EP in laying quails on garlic intervention could be due to differences in diet composition, study design, presentation form, and dose level of garlic. In the current meta-analysis, the results revealed that garlic supported EW, EM, HU, SW, and ST in laying quails, implying the potential of garlic as a performance-enhancing agent in laying quails.

This study revealed that garlic can enhance serum lipid profiles in laying quails, decreasing serum TC, TG, and LDL levels while increasing serum HDL levels. Garlic’s bioactive compounds, such as S-allyl cysteine and allicin, can modulate lipid and cholesterol production by inhibiting the activities of 3-hydroxy-methyl-glutaryl-CoA reductase and sterol 4α-methyl oxidase [24,48]. Another possible explanation for the cholesterol and lipid-lowering effect of garlic in laying quails could be linked to the presence of steroidal saponins, allyl-disulfide, and allyl-sulfhydryl in garlic, which may inhibit cholesterol uptake in the intestine [16,49,50]. The mechanism by which garlic increases serum HDL and reduces TC, TG, and LDL in laying quails is not well known. However, the bioactive compounds and their derivatives may improve serum lipid profiles in laying quails by enhancing bile acid excretion and suppressing the activity of HMG-CoA reductase, a key enzyme in cholesterol formation [15]. The results for serum TC levels support the findings of Yalcin et al. [51], who discovered that garlic supplementation at 0.5 and 1.0% reduced the concentration of TC in the serum of laying hens. The significant reduction on egg yolk cholesterol as observed in laying quails on garlic intervention might be related to the presence of carvacrol, thymol, allicin, and allyl-disulfide or allyl-sulfhydryl group in garlic that suppressed yolk cholesterol synthesis in the liver, possibly through the inhibition of fatty acid synthetase and sterol 4α-methyl oxidase [49], which may in turn lead to acceptability of the egg by consumers. The high serum HDL levels found in laying hens on garlic intervention indicate the high ability of the garlic bioactive ingredients to support the formation of apolipoprotein A-I, the main structural protein of HDL in the liver and intestine [52]. This corroborates the view of Abdulkareem [16], who attributed high serum HDL levels in laying quails to allicin, alliin, and ajoenes contained in garlic.

In this study, EP was higher in laying quails offered garlic at <1.0% than in those given 1.0, 1.5, and >2.0% garlic, implying that <1.0% could be the inclusion level that optimizes EP in laying quails. The reduced serum TG value at a 1% inclusion level when compared to the value obtained at >2.0% inclusion level suggests the high ability of a low dose of garlic to reduce the formation of serum in laying quails. This supports the views of Abdulkareem [16] that laying quails fed 1.0% garlic had significantly lower serum TG content than those offered 0.5 and 1.5% garlic. This might be ascribed to allicin, alliin, and ajoenes, the main bioactive ingredients in garlic [8,47], which attain a threshold level beyond the tolerance level of laying quails [16]. However, a quadratic optimization model should be used to determine the exact administration doses of garlic that optimize EP and serum TG in laying quails.

Age has been demonstrated to influence laying performance in poultry other than quails [53,54]. Meta-regression showed a large effect for age as a covariate for FI, FCR, EP, EW, and HDL in laying quails in the current study. This indicates that as laying quail advanced in age, FI, EP, EW, and serum TG dropped, but FCR and serum HDL increased. These findings corroborate those with others [53,54], who reported that productivity and egg quality gradually declined as hens age. The present results showed that age as a covariate accounted for the majority of the heterogeneity variance across the studies included in the meta-analysis. This indicates the high predictive power of age as a covariate for FI, FCR, EP, and serum HDL. The results also found a small effect for age as a covariate, which explained 27% of heterogeneity variance in serum TG. This suggests the low predictive power of age as a covariate for serum TG in laying quails. Meta-regression showed little effect for garlic dosage as a covariate, and no more than 29% of the inconsistent findings among studies included in the present meta-analysis are explained by garlic dosage. This result also suggests that as the dose levels of garlic increased, serum TG levels increased. This also implies the low predictive power of dose level as a covariate for serum TG in laying quails.

This meta-analysis shows that the duration of garlic intervention is a significant predictor of garlic treatment on FI, serum TC, and HDL in laying quails. Furthermore, results showed that duration of garlic intervention accounted for 21, 11, and 52% of sources of heterogeneity in FI, serum TC, and HDL in laying quails fed garlic-supplemented diets. The present results indicate the low predictive power of duration of garlic intervention as a covariate for FI and serum TC and moderate predictive power on serum TG in laying quails. The heterogeneity not accounted for by the studied moderators could be attributed to factors such as diet composition, garlic form, part of garlic used, quail breed (genotype), and environment (temperature and light), which have been shown to affect laying performance [55].

4.1 Limitations and strengths of the study

This meta-analysis was limited to research on broiler chickens alone and may not apply to other poultry species. Variations in dose levels of garlic, feeding duration, and season of the year the studies used for the meta-analysis was conducted may impact the reliability of the pooled results. The low number of studies used to compute EM, HU, ST, egg cholesterol, and serum LDL may have an impact on the pool results. Also, differences in the age of quails used for the meta-analysis, assay types, and analytical methods adopted by authors whose studies were used for the analysis may pose a limitation. Even though the Egger regression asymmetry indicated the absence of publication bias, the existence of publication bias may not be fully ruled out. Despite these drawbacks, the strength of this meta-analysis is to characterize an uncharacterized study on the impact of garlic on productive performance, egg quality, and lipid profiles of laying quails to resolve uncertainty and create new insights. This research also sets the guidelines for standardized experimental designs on the use of garlic as a feed additive in laying quail diets in the future.

5 Conclusion and future study

This study revealed the potential of garlic intervention to increase EP, EW, and serum HDL, and reduce FCR, serum TC, TG, LDL, and EC in laying quails with evidence of significant heterogeneity. The Egger’s test results indicate the absence of publication bias in this meta-analysis. Restricted subgroup results revealed that laying quails that were offered <1.0% garlic produced more eggs than those offered garlic at 1.0, 1.5, and >2.0%, implying that garlic should be added to quail diets at a level less than 1.0% for improved EP. Conversely, quails that received garlic at 1.0% had significantly lower serum TG than in laying quails that received garlic at >2.0%. This suggests that the inclusion of high doses of garlic in laying quail diets may not enhance lipid profiles in laying quails. Meta-regression analysis indicated that quail age, garlic dosage, and duration of garlic intervention accounted for most of the sources of significant heterogeneity across studies included in the study. However, more research is needed to determine the exact inclusion levels of garlic that optimize lipid profiles, EP, and quality in laying quails. The use of molecular biological tools to understand how garlic enhances EP and lipid profiles in laying quails is needed, as such information is lacking in the literature. Further research is required to ascertain the long-time garlic feeding on laying quail performance and lipid profiles of laying quails, as most of the studies included in the meta-analysis lasted for <10 weeks. Also, future research into garlic’s synergistic effects with other feed additives in laying quail performance is needed.

  1. Funding information: Authors state no funding involved.

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and consented to its submission to the journal, reviewed all the results and approved the final version of the manuscript. CAM conceptualized this meta-analysis. IPO and MM extracted and analysed the data. CAM, MM, and IPO wrote the manuscript, and the final draft was read and approved by the authors.

  3. Conflict of interest: Authors state no conflict of interest.

  4. Data availability statement: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

References

[1] Mnisi CM, Marareni M, Manyeula F, Madibana MJ. A way forward for the South African quail sector as a potential contributor to food and nutrition security following the aftermath of COVID-19: a review. Agric Food Secur. 2021;10:48. 10.1186/s40066-021-00331-8.Suche in Google Scholar PubMed PubMed Central

[2] Khalifa AH, Omar MB, Hussein SM, Abdel-Mbdy HE. Nutritional value of farmed and wild quail meats. Assiut J Agric Sci. 2016;47:58–71.10.21608/ajas.2016.2574Suche in Google Scholar

[3] Muscogiuri G, Barrea L, Savastano S, Colao A. Nutritional recommendations for COVID-19 quarantine. Eur J Clin Nutr. 2020;74(6):850–1. 10.1038/s41430-020-0635-2.Suche in Google Scholar PubMed PubMed Central

[4] Tunsaringkarn T, Tungjaroenchai W, Siriwong W. Nutrient benefits of quail (Coturnix coturnix japonica) eggs. Int J Sci Res. 2013;3:1–8.Suche in Google Scholar

[5] Ali MA, Abd El-Aziz AA. Comparative study on nutritional value of quail and chicken eggs. J Res Field Specif Educ. 2019;15:39–56.10.21608/jedu.2019.73533Suche in Google Scholar

[6] Jeke A, Phiri C, Chitiindingu K, Taru P. Nutritional compositions of Japanese quail (Coturnix coturnix japonica) breed lines raised on a basal poultry ration under farm conditions in Ruwa, Zimbabwe. Cogent Food Agric. 2018;4:1473009. 10.1080/23311932.2018.1473009.Suche in Google Scholar

[7] Tessari M. Non-essential amino acids usage for protein replenishment in humans in humans: a method of estimation. Am J Clin Nutr. 2019;110:255–64.10.1093/ajcn/nqz039Suche in Google Scholar PubMed

[8] Ogbuewu IP, Okoro VMO, Mbajiorgu EF, Mbajiorgu CA. Beneficial effect of garlic (Allium sativum) in livestock and poultry nutrition: A review. Agric Res. 2019;8:411–26. 10.1007/s40003-018-0390-y.Suche in Google Scholar

[9] Ogbuewu IP, Okoro VMO, Mbajiorgu CA. Meta-analysis of the responses of laying hens to garlic (Allium sativum) supplementation. Anim Feed Sci Technol. 2021;275:114866.10.1016/j.anifeedsci.2021.114866Suche in Google Scholar

[10] Tavares L, Santos L, Pelayo C, Noreña PZ. Bioactive compounds of garlic: A comprehensive review of encapsulation technologies, characterization of the encapsulated garlic compounds and their industrial applicability. Trends Food Sci Technol. 2021;114:232–44.10.1016/j.tifs.2021.05.019Suche in Google Scholar

[11] Ogbuewu IP, Mbajiorgu CA. Meta-analysis of the impact of garlic supplementation on aspects of egg yolk quality characteristics of laying hens. Int J Agric Biol. 2022;28:319–26.Suche in Google Scholar

[12] Meza-Rios A, Velazquez-Juarez G, Castellanos-Huerta I, Lopez-Roa RI, Anguiano-Sevilla LA, Hernanez-Velasco X, et al. The beneficial effects of components of garlic (Allium sativum L.) in the poultry industry. Food Nutr Sci. 2024;15:27–57.10.4236/fns.2024.151002Suche in Google Scholar

[13] Nam H, Jung H, Kim Y, Kim B, Kim KH, Park SJ, et al. Aged black garlic extract regulates lipid metabolism by inhibiting lipogenesis and promoting lipolysis in mature 3T3-L1 adipocytes. Food Sci Biotechnol. 2017;27:575–9.10.1007/s10068-017-0268-ySuche in Google Scholar PubMed PubMed Central

[14] El-Saber BG, Magdy BA, Wasef L, Elewa YHA, Al-Sagan A, Abd El-Hack ME, et al. Chemical constituents and pharmacological activities of garlic (Allium sativum L.): A review. Nutrients. 2020;12:872.10.3390/nu12030872Suche in Google Scholar PubMed PubMed Central

[15] Sun YE, Wang W, Qin J. Anti-hyperlipidemia of garlic by reducing the level of total cholesterol and low-density lipoprotein: A meta-analysis. Medicine. 2018;97(18):e0255.10.1097/MD.0000000000010255Suche in Google Scholar PubMed PubMed Central

[16] Abdulkareem ZA. Effect of dietary supplementation of wild leek (Allium tricoccum) and garlic (Allium sativum) leaves on production, egg quality, serum lipid profile, intestinal morphology and nutrient digestibility of laying quails. Trop Anim Health Prod. 2024;56:224.10.1007/s11250-024-04090-zSuche in Google Scholar PubMed

[17] Olayinka OI, Bawa GS, Abeke FO, Afolayan M. Comparative evaluation of garlic (Allium sativum) meal as natural feed additives on egg production and egg quality of laying Japanese quails. Niger J Anim Sci Technol. 2022;5:47–55.Suche in Google Scholar

[18] Yalcın S, Onbasılar I, Sehu A, Yalcın S. The effects of dietary garlic powder on the performance, egg traits and serum cholesterol of laying quails. Asian-Austral J Anim Sci. 2007;20:944–7.10.5713/ajas.2007.944Suche in Google Scholar

[19] Behnamifar A, Rahimi S, Karimi Torshizi MA, Hasanpour S, Mohammadzade Z. Effect of thyme, garlic and caraway herbal extracts on blood parameters, productivity, egg quality, hatchability and intestinal bacterial population of laying Japanese quail. Iran J Vet Med. 2015;9:179–87.Suche in Google Scholar

[20] Khan SH, Hasan S, Sardar R, Anjum MA. Effects of dietary garlic powder on cholesterol concentration in Native Desi laying hens. Am J Food Technol. 2008;3:207–13.10.3923/ajft.2008.207.213Suche in Google Scholar

[21] Rusli RK, Sadarman S, Hidayat C, Sholikin MM, Hilmi M, Yuniza A, et al. A meta-analysis to evaluate the effects of garlic supplementation on performance and blood lipids profile of broiler chickens. Livest Sci. 2022;26:105022.10.1016/j.livsci.2022.105022Suche in Google Scholar

[22] Xin Y, Sun H, Liu S, Lan B, Zhao G, Yin S, et al. Effects of vegetable oils on feed intake, nutrient digestibility, ruminal parameters, lactation performance, and milk fatty acid composition in cattle: A meta-analysis. Anim Feed Sci Technol. 2025;1–34. 10.1016/j.anifeedsci.2025.116286.Suche in Google Scholar

[23] Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:71. 10.1136/bmj.n71.Suche in Google Scholar PubMed PubMed Central

[24] Taleb HM, Ramadan GS, Fouad AM, AbdelHalim AA, Kasem HT. Effect of using black seed, garlic and licorice on carcass characteristics and blood parameters of Japanese quail. Egypt J Vet Sci. 2023;54:1201–13.10.21608/ejvs.2023.213856.1514Suche in Google Scholar

[25] Rohatgi A. WebPlotDigitizer, Version: 4.5. Pacifica, California; USA: 2021. https://automeris.io/WebPlotDigitizer/ (accessed March 2022).Suche in Google Scholar

[26] Wallace BC, Lajeunesse MJ, Dietz G, Dahabreh IJ, Trikalinos TA, Schmid CH, et al. OpenMEE: intuitive, open-source software for meta-analysis in ecology and evolutionary biology. Methods Ecol Evol. 2016;8:941–7. 10.1111/2041-210X.12708.Suche in Google Scholar

[27] Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. Brit Med J. 2003;327:557–60. 10.1136/bmj.327.7414.557.Suche in Google Scholar PubMed PubMed Central

[28] Sierra-Galicia MI, Rodríguez-de Lara R, Orzuna-Orzuna JF, Lara-Bueno A, Ramírez-Valverde R, Fallas-Lopez M. Effects of supplementation with bee pollen and propolis on growth performance and serum metabolites of rabbits: A meta-analysis. Animals. 2023;13:439.10.3390/ani13030439Suche in Google Scholar PubMed PubMed Central

[29] Hernandez-García PA, Orzuna-Orzuna JF, Chay-Canul AJ, Silva GV, Galvan CD, Ortíz PBR. Meta-analysis of organic chromium dietary supplementation on growth performance, carcass traits, and serum metabolites of lambs. Small Rum Res. 2024;233:107254.10.1016/j.smallrumres.2024.107254Suche in Google Scholar

[30] Ogbuewu IP, Okoro VM, Mbajiorgu CA. Meta-analysis of the influence of phytobiotic (pepper) supplementation in broiler chicken performance. Trop Anim Health Prod. 2020;52:17–30.10.1007/s11250-019-02118-3Suche in Google Scholar PubMed

[31] Canogullari S, Baylan M, Erdogan Z, Duzguner V, Kucukgul A. The effects of dietary garlic powder on performance, egg yolk andserum cholesterol concentrations in laying quails. Czeh J Anim Sci. 2010;55:286–93.10.17221/126/2009-CJASSuche in Google Scholar

[32] Zeweil H, Dosoky W, Farag S, Basyony M. Effect of dried garlic and hot pepper as feed additives on the performance and egg quality of laying Japanese quail hens. Egg Meat Symposia. 2011. p. 1–10.Suche in Google Scholar

[33] Omonoma AO, Jarikre TA. Effect of garlic supplemented diets on the hematological and lipid profiles of Japanese quail (Cotunix coturnix japonica). Niger Vet J. 2014;35:981–8.Suche in Google Scholar

[34] Abdou A, Rashed GA. Effect of black seed (Nigella sativa) and garlic (Allium sativum) feed supplements on productive performance and some physiological and immunological responses of Japanese quail. Egypt J Nutr Feed. 2015;18:129–41.10.21608/ejnf.2015.104793Suche in Google Scholar

[35] Udeh FU, Nwakor CM, Ani AO, Onodugo MO, Onah CC. Effect of dietary garlic powder on the egg quality traits and cholesterol profile of Japanese quail eggs. Proceedings of the 41st Conference of Nigerian Society for Animal Production, 20–24 March, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria. 2016. p. 607–10.Suche in Google Scholar

[36] Swain P, Mohapatra LM, Sethy K, Sahoo PR, Nayak SM, Patro P, et al. Effect of ginger and garlic supplement on growth and hemato-biochemical profile of Japanese quail (Coturnix coturnix japonica). Explor Anim Med Res. 2017;7:77–83.Suche in Google Scholar

[37] Udeh FU, Onah CC, Nwakor CM, Onodugo MO, Udeh VC, Ozor D. Effect of dietary garlic powder on the hematology and cholesterol level of Japanese quail. Proceedings of 43rd Annual Conference of the Nigerian Society for Animal Production, March 18th – 22nd 2018, FUT Owerri. 2018. p. 1039–41.Suche in Google Scholar

[38] Bhavani MD, Kumar DS, Kishore KR, Kumari KNR. Effect of inclusion of dried garlic (Allium sativum) powder in the diet on serum biochemical profile of Japanese quail. J Anim Res. 2021;11:81–7.10.30954/2277-940X.01.2021.10Suche in Google Scholar

[39] Mohammed ZQ, Ezaddin IN, Khalaf IA. Comparison of the effect of using different levels of local garlic and black seed powder with the probiotic in the diets on the productive and quality traits of quail eggs. Nat Volat Essent Oils. 2021;8:2612–21.Suche in Google Scholar

[40] Ismael LA, Ameen EM. Reproductive, biochemical, and hormonal traits of local quail in response to dietary supplementation of dried garlic powder. Iraqi J Agric Sci. 2022;53:278–87.10.36103/ijas.v53i2.1535Suche in Google Scholar

[41] Mohammed AM, Hussein SM, Shaker AS. Effect of adding garlic powder and local red sumac to quail diets on productive performance and some blood biochemical characteristics during the growth stage in cages. 4th International Conference of Modern Technologies in Agricultural Sciences, IOP Conference Series: Earth and Environmental Science. Vol. 1262. 2023. p. 072113. 10.1088/1755-1315/1262/7/072113.Suche in Google Scholar

[42] Nurhayati B, Nelwida A, Muthalib R, Alwi DY. Effect of using black garlic instead of fresh garlic in the ration on the performances and blood cholesterol properties of quail. J Agripet. 2023;23:91–7.10.17969/agripet.v23i1.27604Suche in Google Scholar

[43] Hidayatik N, Yuliani GA, Agustono B, Kristianingtyas L, Novianti AN, Hetansh EP. Khairullah, et al. Effect of garlic extract (Allium sativum) on hematological and clinical chemistry parameters of laying quail. Asian J Dairy Food Res. 2024;43:790–5.10.18805/ajdfr.DRF-408Suche in Google Scholar

[44] Kour G, Khan N, Sharma RK, Mahajan V, Bhat ZF, Khandii SA. Influence of supplementation of phytogenic feed additives on egg quality of layer quail. Indian J Anim Res. 2024;1–8. 10.18805/IJAR.B-5273.Suche in Google Scholar

[45] Raya AH, El Sherif KH, Rabie MH, Bedair HF. Effect of dietary supplementation with dried garlic and thyme on growth performance of Japanese quail. J Anim Poult Prod Mansoura Univ. 2014;5:73–85.10.21608/jappmu.2014.68610Suche in Google Scholar

[46] Egger M, Smith GD, Schneider M, Minder C. Bias in meta-analysis detected by a simple graphical test. BMJ. 1997;315:629. 10.1136/bmj.315.7109.629.Suche in Google Scholar PubMed PubMed Central

[47] Ansary J, Forbes-Hernández TY, Gil E, Cianciosi D, Zhang J, Elexpuru-Zabaleta M, et al. Potential health benefit of garlic based on human intervention studies: A brief overview. Antioxidants. 2020;9:619. 10.3390/antiox9070619.Suche in Google Scholar PubMed PubMed Central

[48] Amagase H. Clarifying the real bioactive constituents of garlic. J Nutr. 2006;136:716S–25S. 10.1093/jn/136.3.716S.Suche in Google Scholar PubMed

[49] Singh DK, Porter TD. Inhibition of sterol 4α-methyl oxidase is the principal mechanism by which garlic decreases cholesterol synthesis. J Nutr. 2006;136:759S–64S.10.1093/jn/136.3.759SSuche in Google Scholar PubMed

[50] Sobolewska D, Michalska K, Podolak I, Grabowska K. Steroidal saponins from the genus Allium. Phytochem Rev. 2016;15:1–35.10.1007/s11101-014-9381-1Suche in Google Scholar PubMed PubMed Central

[51] Yalcin S, Onbasilar EE, Reisli Z, Yalcin S. Effect of garlic powder on the performance, egg traits and blood parameters of laying hens. J Sci Food Agric. 2006;86:1336–9.10.1002/jsfa.2515Suche in Google Scholar

[52] Ginsberg HN. Lipoprotein physiology. Endocrinol Metab Clin North Am. 1998;27:503–19.10.1016/S0889-8529(05)70023-2Suche in Google Scholar

[53] Sekeroglu A, Duman M, Tahtalı Y, Yıldırım A, Eleroglu H. Effect of cage tier and age on performance, egg quality and stress parameters of laying hens. South Afr J Anim Sci. 2014;44:288–97.10.4314/sajas.v44i3.11Suche in Google Scholar

[54] Tan YG, Xu XL, Cao HY, Zhou W, Yin ZZ. Effect of age at first egg on reproduction performance and characterization of the hypothalamo–pituitary–gonadal axis in chickens. Poult Sci. 2021;100:101325. 10.1016/j.psj.2021.101325.Suche in Google Scholar PubMed PubMed Central

[55] Jacob JP, Wilson HR, Miles RD, Butcher GD, Mather FB. Factors affecting egg production in backyard chicken flocks. 2018. https://edis.ifas.ufl.edu/publication/PS029.Suche in Google Scholar
Received: 2025-04-12
Revised: 2025-06-06
Accepted: 2025-06-06
Published Online: 2025-09-03

© 2025 the author(s), published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Artikel in diesem Heft

  1. Research Articles
  2. Optimization of sustainable corn–cattle integration in Gorontalo Province using goal programming
  3. Competitiveness of Indonesia’s nutmeg in global market
  4. Toward sustainable bioproducts from lignocellulosic biomass: Influence of chemical pretreatments on liquefied walnut shells
  5. Efficacy of Betaproteobacteria-based insecticides for managing whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), on cucumber plants
  6. Assessment of nutrition status of pineapple plants during ratoon season using diagnosis and recommendation integrated system
  7. Nutritional value and consumer assessment of 12 avocado crosses between cvs. Hass × Pionero
  8. The lacked access to beef in the low-income region: An evidence from the eastern part of Indonesia
  9. Comparison of milk consumption habits across two European countries: Pilot study in Portugal and France
  10. Antioxidant responses of black glutinous rice to drought and salinity stresses at different growth stages
  11. Differential efficacy of salicylic acid-induced resistance against bacterial blight caused by Xanthomonas oryzae pv. oryzae in rice genotypes
  12. Yield and vegetation index of different maize varieties and nitrogen doses under normal irrigation
  13. Urbanization and forecast possibilities of land use changes by 2050: New evidence in Ho Chi Minh city, Vietnam
  14. Organizational-economic efficiency of raspberry farming – case study of Kosovo
  15. Application of nitrogen-fixing purple non-sulfur bacteria in improving nitrogen uptake, growth, and yield of rice grown on extremely saline soil under greenhouse conditions
  16. Digital motivation, knowledge, and skills: Pathways to adaptive millennial farmers
  17. Investigation of biological characteristics of fruit development and physiological disorders of Musang King durian (Durio zibethinus Murr.)
  18. Enhancing rice yield and farmer welfare: Overcoming barriers to IPB 3S rice adoption in Indonesia
  19. Simulation model to realize soybean self-sufficiency and food security in Indonesia: A system dynamic approach
  20. Gender, empowerment, and rural sustainable development: A case study of crab business integration
  21. Metagenomic and metabolomic analyses of bacterial communities in short mackerel (Rastrelliger brachysoma) under storage conditions and inoculation of the histamine-producing bacterium
  22. Fostering women’s engagement in good agricultural practices within oil palm smallholdings: Evaluating the role of partnerships
  23. Increasing nitrogen use efficiency by reducing ammonia and nitrate losses from tomato production in Kabul, Afghanistan
  24. Physiological activities and yield of yacon potato are affected by soil water availability
  25. Vulnerability context due to COVID-19 and El Nino: Case study of poultry farming in South Sulawesi, Indonesia
  26. Wheat freshness recognition leveraging Gramian angular field and attention-augmented resnet
  27. Suggestions for promoting SOC storage within the carbon farming framework: Analyzing the INFOSOLO database
  28. Optimization of hot foam applications for thermal weed control in perennial crops and open-field vegetables
  29. Toxicity evaluation of metsulfuron-methyl, nicosulfuron, and methoxyfenozide as pesticides in Indonesia
  30. Fermentation parameters and nutritional value of silages from fodder mallow (Malva verticillata L.), white sweet clover (Melilotus albus Medik.), and their mixtures
  31. Five models and ten predictors for energy costs on farms in the European Union
  32. Effect of silvopastoral systems with integrated forest species from the Peruvian tropics on the soil chemical properties
  33. Transforming food systems in Semarang City, Indonesia: A short food supply chain model
  34. Understanding farmers’ behavior toward risk management practices and financial access: Evidence from chili farms in West Java, Indonesia
  35. Optimization of mixed botanical insecticides from Azadirachta indica and Calophyllum soulattri against Spodoptera frugiperda using response surface methodology
  36. Mapping socio-economic vulnerability and conflict in oil palm cultivation: A case study from West Papua, Indonesia
  37. Exploring rice consumption patterns and carbohydrate source diversification among the Indonesian community in Hungary
  38. Determinants of rice consumer lexicographic preferences in South Sulawesi Province, Indonesia
  39. Effect on growth and meat quality of weaned piglets and finishing pigs when hops (Humulus lupulus) are added to their rations
  40. Healthy motivations for food consumption in 16 countries
  41. The agriculture specialization through the lens of PESTLE analysis
  42. Combined application of chitosan-boron and chitosan-silicon nano-fertilizers with soybean protein hydrolysate to enhance rice growth and yield
  43. Stability and adaptability analyses to identify suitable high-yielding maize hybrids using PBSTAT-GE
  44. Phosphate-solubilizing bacteria-mediated rock phosphate utilization with poultry manure enhances soil nutrient dynamics and maize growth in semi-arid soil
  45. Factors impacting on purchasing decision of organic food in developing countries: A systematic review
  46. Influence of flowering plants in maize crop on the interaction network of Tetragonula laeviceps colonies
  47. Bacillus subtilis 34 and water-retaining polymer reduce Meloidogyne javanica damage in tomato plants under water stress
  48. Vachellia tortilis leaf meal improves antioxidant activity and colour stability of broiler meat
  49. Evaluating the competitiveness of leading coffee-producing nations: A comparative advantage analysis across coffee product categories
  50. Application of Lactiplantibacillus plantarum LP5 in vacuum-packaged cooked ham as a bioprotective culture
  51. Evaluation of tomato hybrid lines adapted to lowland
  52. South African commercial livestock farmers’ adaptation and coping strategies for agricultural drought
  53. Spatial analysis of desertification-sensitive areas in arid conditions based on modified MEDALUS approach and geospatial techniques
  54. Meta-analysis of the effect garlic (Allium sativum) on productive performance, egg quality, and lipid profiles in laying quails
  55. Optimizing carrageenan–citric acid synergy in mango gummies using response surface methodology
  56. The strategic role of agricultural vocational training in sustainable local food systems
  57. Agricultural planning grounded in regional rainfall patterns in the Colombian Orinoquia: An essential step for advancing climate-adapted and sustainable agriculture
  58. Perspectives of master’s graduates on organic agriculture: A Portuguese case study
  59. Developing a behavioral model to predict eco-friendly packaging use among millennials
  60. Government support during COVID-19 for vulnerable households in Central Vietnam
  61. Citric acid–modified coconut shell biochar mitigates saline–alkaline stress in Solanum lycopersicum L. by modulating enzyme activity in the plant and soil
  62. Herbal extracts: For green control of citrus Huanglongbing
  63. Research on the impact of insurance policies on the welfare effects of pork producers and consumers: Evidence from China
  64. Investigating the susceptibility and resistance barley (Hordeum vulgare L.) cultivars against the Russian wheat aphid (Diuraphis noxia)
  65. Characterization of promising enterobacterial strains for silver nanoparticle synthesis and enhancement of product yields under optimal conditions
  66. Testing thawed rumen fluid to assess in vitro degradability and its link to phytochemical and fibre contents in selected herbs and spices
  67. Protein and iron enrichment on functional chicken sausage using plant-based natural resources
  68. Fruit and vegetable intake among Nigerian University students: patterns, preferences, and influencing factors
  69. Bioprospecting a plant growth-promoting and biocontrol bacterium isolated from wheat (Triticum turgidum subsp. durum) in the Yaqui Valley, Mexico: Paenibacillus sp. strain TSM33
  70. Quantifying urban expansion and agricultural land conversion using spatial indices: evidence from the Red River Delta, Vietnam
  71. Review Articles
  72. Reference dietary patterns in Portugal: Mediterranean diet vs Atlantic diet
  73. Evaluating the nutritional, therapeutic, and economic potential of Tetragonia decumbens Mill.: A promising wild leafy vegetable for bio-saline agriculture in South Africa
  74. A review on apple cultivation in Morocco: Current situation and future prospects
  75. Quercus acorns as a component of human dietary patterns
  76. CRISPR/Cas-based detection systems – emerging tools for plant pathology
  77. Short Communications
  78. An analysis of consumer behavior regarding green product purchases in Semarang, Indonesia: The use of SEM-PLS and the AIDA model
  79. Effect of NaOH concentration on production of Na-CMC derived from pineapple waste collected from local society
https://doi.org/10.1515/opag-2025-0455
Schlagwörter für diesen Artikel
blood characteristics; feed conversion ratio; feed intake; meta-regression; yolk cholesterol
Creative Commons
BY 4.0

Artikel in diesem Heft

  1. Research Articles
  2. Optimization of sustainable corn–cattle integration in Gorontalo Province using goal programming
  3. Competitiveness of Indonesia’s nutmeg in global market
  4. Toward sustainable bioproducts from lignocellulosic biomass: Influence of chemical pretreatments on liquefied walnut shells
  5. Efficacy of Betaproteobacteria-based insecticides for managing whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), on cucumber plants
  6. Assessment of nutrition status of pineapple plants during ratoon season using diagnosis and recommendation integrated system
  7. Nutritional value and consumer assessment of 12 avocado crosses between cvs. Hass × Pionero
  8. The lacked access to beef in the low-income region: An evidence from the eastern part of Indonesia
  9. Comparison of milk consumption habits across two European countries: Pilot study in Portugal and France
  10. Antioxidant responses of black glutinous rice to drought and salinity stresses at different growth stages
  11. Differential efficacy of salicylic acid-induced resistance against bacterial blight caused by Xanthomonas oryzae pv. oryzae in rice genotypes
  12. Yield and vegetation index of different maize varieties and nitrogen doses under normal irrigation
  13. Urbanization and forecast possibilities of land use changes by 2050: New evidence in Ho Chi Minh city, Vietnam
  14. Organizational-economic efficiency of raspberry farming – case study of Kosovo
  15. Application of nitrogen-fixing purple non-sulfur bacteria in improving nitrogen uptake, growth, and yield of rice grown on extremely saline soil under greenhouse conditions
  16. Digital motivation, knowledge, and skills: Pathways to adaptive millennial farmers
  17. Investigation of biological characteristics of fruit development and physiological disorders of Musang King durian (Durio zibethinus Murr.)
  18. Enhancing rice yield and farmer welfare: Overcoming barriers to IPB 3S rice adoption in Indonesia
  19. Simulation model to realize soybean self-sufficiency and food security in Indonesia: A system dynamic approach
  20. Gender, empowerment, and rural sustainable development: A case study of crab business integration
  21. Metagenomic and metabolomic analyses of bacterial communities in short mackerel (Rastrelliger brachysoma) under storage conditions and inoculation of the histamine-producing bacterium
  22. Fostering women’s engagement in good agricultural practices within oil palm smallholdings: Evaluating the role of partnerships
  23. Increasing nitrogen use efficiency by reducing ammonia and nitrate losses from tomato production in Kabul, Afghanistan
  24. Physiological activities and yield of yacon potato are affected by soil water availability
  25. Vulnerability context due to COVID-19 and El Nino: Case study of poultry farming in South Sulawesi, Indonesia
  26. Wheat freshness recognition leveraging Gramian angular field and attention-augmented resnet
  27. Suggestions for promoting SOC storage within the carbon farming framework: Analyzing the INFOSOLO database
  28. Optimization of hot foam applications for thermal weed control in perennial crops and open-field vegetables
  29. Toxicity evaluation of metsulfuron-methyl, nicosulfuron, and methoxyfenozide as pesticides in Indonesia
  30. Fermentation parameters and nutritional value of silages from fodder mallow (Malva verticillata L.), white sweet clover (Melilotus albus Medik.), and their mixtures
  31. Five models and ten predictors for energy costs on farms in the European Union
  32. Effect of silvopastoral systems with integrated forest species from the Peruvian tropics on the soil chemical properties
  33. Transforming food systems in Semarang City, Indonesia: A short food supply chain model
  34. Understanding farmers’ behavior toward risk management practices and financial access: Evidence from chili farms in West Java, Indonesia
  35. Optimization of mixed botanical insecticides from Azadirachta indica and Calophyllum soulattri against Spodoptera frugiperda using response surface methodology
  36. Mapping socio-economic vulnerability and conflict in oil palm cultivation: A case study from West Papua, Indonesia
  37. Exploring rice consumption patterns and carbohydrate source diversification among the Indonesian community in Hungary
  38. Determinants of rice consumer lexicographic preferences in South Sulawesi Province, Indonesia
  39. Effect on growth and meat quality of weaned piglets and finishing pigs when hops (Humulus lupulus) are added to their rations
  40. Healthy motivations for food consumption in 16 countries
  41. The agriculture specialization through the lens of PESTLE analysis
  42. Combined application of chitosan-boron and chitosan-silicon nano-fertilizers with soybean protein hydrolysate to enhance rice growth and yield
  43. Stability and adaptability analyses to identify suitable high-yielding maize hybrids using PBSTAT-GE
  44. Phosphate-solubilizing bacteria-mediated rock phosphate utilization with poultry manure enhances soil nutrient dynamics and maize growth in semi-arid soil
  45. Factors impacting on purchasing decision of organic food in developing countries: A systematic review
  46. Influence of flowering plants in maize crop on the interaction network of Tetragonula laeviceps colonies
  47. Bacillus subtilis 34 and water-retaining polymer reduce Meloidogyne javanica damage in tomato plants under water stress
  48. Vachellia tortilis leaf meal improves antioxidant activity and colour stability of broiler meat
  49. Evaluating the competitiveness of leading coffee-producing nations: A comparative advantage analysis across coffee product categories
  50. Application of Lactiplantibacillus plantarum LP5 in vacuum-packaged cooked ham as a bioprotective culture
  51. Evaluation of tomato hybrid lines adapted to lowland
  52. South African commercial livestock farmers’ adaptation and coping strategies for agricultural drought
  53. Spatial analysis of desertification-sensitive areas in arid conditions based on modified MEDALUS approach and geospatial techniques
  54. Meta-analysis of the effect garlic (Allium sativum) on productive performance, egg quality, and lipid profiles in laying quails
  55. Optimizing carrageenan–citric acid synergy in mango gummies using response surface methodology
  56. The strategic role of agricultural vocational training in sustainable local food systems
  57. Agricultural planning grounded in regional rainfall patterns in the Colombian Orinoquia: An essential step for advancing climate-adapted and sustainable agriculture
  58. Perspectives of master’s graduates on organic agriculture: A Portuguese case study
  59. Developing a behavioral model to predict eco-friendly packaging use among millennials
  60. Government support during COVID-19 for vulnerable households in Central Vietnam
  61. Citric acid–modified coconut shell biochar mitigates saline–alkaline stress in Solanum lycopersicum L. by modulating enzyme activity in the plant and soil
  62. Herbal extracts: For green control of citrus Huanglongbing
  63. Research on the impact of insurance policies on the welfare effects of pork producers and consumers: Evidence from China
  64. Investigating the susceptibility and resistance barley (Hordeum vulgare L.) cultivars against the Russian wheat aphid (Diuraphis noxia)
  65. Characterization of promising enterobacterial strains for silver nanoparticle synthesis and enhancement of product yields under optimal conditions
  66. Testing thawed rumen fluid to assess in vitro degradability and its link to phytochemical and fibre contents in selected herbs and spices
  67. Protein and iron enrichment on functional chicken sausage using plant-based natural resources
  68. Fruit and vegetable intake among Nigerian University students: patterns, preferences, and influencing factors
  69. Bioprospecting a plant growth-promoting and biocontrol bacterium isolated from wheat (Triticum turgidum subsp. durum) in the Yaqui Valley, Mexico: Paenibacillus sp. strain TSM33
  70. Quantifying urban expansion and agricultural land conversion using spatial indices: evidence from the Red River Delta, Vietnam
  71. Review Articles
  72. Reference dietary patterns in Portugal: Mediterranean diet vs Atlantic diet
  73. Evaluating the nutritional, therapeutic, and economic potential of Tetragonia decumbens Mill.: A promising wild leafy vegetable for bio-saline agriculture in South Africa
  74. A review on apple cultivation in Morocco: Current situation and future prospects
  75. Quercus acorns as a component of human dietary patterns
  76. CRISPR/Cas-based detection systems – emerging tools for plant pathology
  77. Short Communications
  78. An analysis of consumer behavior regarding green product purchases in Semarang, Indonesia: The use of SEM-PLS and the AIDA model
  79. Effect of NaOH concentration on production of Na-CMC derived from pineapple waste collected from local society
Jetzt anmelden und 20% sparen
Institutioneller Zugang
Wie funktioniert Authentifizierung?
Haben Sie eine Idee, wie wir unsere Website verbessern können?
Bitte schreiben Sie uns.
© 2025 De Gruyter Brill
Heruntergeladen am 8.12.2025 von https://www.degruyterbrill.com/document/doi/10.1515/opag-2025-0455/html
Button zum nach oben scrollen