Abstract
Nutritional strategies that improve growth indices in chickens without reducing reproductive rate are desirable in the light of increasing feed cost. Several feeding studies on the use of dietary ginger to enhance performance in chickens have been at variance with one and another. Some authors have observed positive effect of ginger supplementation on chicken performance, while others have not. Thus, it is become germane for animal nutritionists and poultry farmers to ascertain the effect of dietary ginger on chicken performance as to make evidence based decisions about the use of ginger in their feeding systems. One way to confirm efficacy of dietary ginger on chicken performance is to pool the findings of individual authors using meta-analytical tools. Hence, the dataset of twenty-one individual studies on the effect of ginger supplementation on the production outcomes (feed intake, weight gain, feed conversion ratio (FCR), organ weight, semen traits and serum lipid profiles) of chickens were subjected to meta-analysis to pinpoint variations in the measured production variables using OPENMEE, an open source software. Meta-regression was used to determine the sources of heterogeneity. Inclusion criteria for the study were information on the presentation form, adequate description of randomization, production data, and associated measures of variance (SE or SD) and p-values. Results revealed that ginger supplementation significantly improved semen volume (d = 0.868; 95%CI = 0.195 to 1.542), sperm motility (d = 0.581; 95%CI = 10.229 to 1.446), body weight gain (d = 0.495; 95%CI = 10.041 to 0.949), FCR (d = -0.732; 95%CI = -1.195 to -0.270) and serum cholesterol level (d = -0.985; 95%CI = -1.653 to -0.316) from zero. Other outcomes measured were not significantly affected. It can be concluded that dietary ginger supplementation improved body weight gain, feed conversion ratio, serum cholesterol content, semen output and spermatozoa motility in chickens.