Meta-Analysis of the Effect of Ginger (Zingiber officinale) on Semen Quality Characteristics of Breeder Cocks

Abstract

Some authors have reported positive associations between dietary ginger and semen quality in birds, whereas others have not confirmed this. The objective of this study was to evaluate semen quality of breeders cocks fed diets supplemented with different levels of ginger using meta-analysis. The database was created on articles published in peer-reviewed journals and 20 peer[1]reviewed journal articles on the effect of ginger on semen quality of chickens were identified using Google search engine. A total of 5 peer-reviewed articles were selected after meeting apriori quality criteria. Data for each study were extracted and analyzed using OpenMEE software. The estimated effect size of ginger was calculated for semen volume (SV), sperm motility (SM), sperm concentration (SC), live sperm (LS) and abnormal sperm (AS). The pooled estimate for SV was 0.905 ml, with a 95% confidence interval (CI) from 0.189 to 1.621 and the pooled estimate for SM was 0.026 with a 95% CI from -1.668 to 1.720. The pooled estimates for SC and LS were 1.209 and 0.173 with a 95% CI from -1.899 to 2.245 and -1.953 to -0.948, respectively. Four out of the 5 outcomes displayed high heterogeneity of ginger response (I 2 , which is a measure of variation beyond chance, I² = 74.28% for SV, 96.34% for SM, 99.06% for SC and 97.33% for LS). AS had moderate heterogeneity (I 2 = 43.89%). These findings confirm that dietary ginger supplementation in chicken significantly improved semen volume and reduced the percentage of sperm with abnormal cells but had no significant effect on sperm concentration, motility, and live sperm.