A Meta-Analysis of Genetic Parameter Estimates for Economically Important Traits in Iranian Indigenous Chickens

This study aimed to perform a meta-analysis to combine genetic parameters for economically important traits of Iranian indigenous chickens. A data set of information related to different growth, reproduction, and egg quality traits including ۳۳۶ heritability estimates and ۴۳۳ genetic correlations from ۴۵ articles published between ۲۰۰۷ and ۲۰۱۹ were used. Meta-analysis was performed based on a random-effects model to calculate the effect size for genetic parameters. Also, statistic and Q test were used to measure the degree of heterogeneity among studies. The mean heritability for growth traits ranged from ۰.۲۲۲ (body weight at hatch) to ۰.۳۴ (body weight at ۱۲ weeks of age). The lowest and highest estimates of the heritability for reproductive traits were ۰.۱۸۱ (number of eggs produced) and ۰.۴۴۹ (age at sexual maturity), respectively. The mean heritability estimate for egg internal quality traits varied from ۰.۲۱۱ (yolk weight) to ۰.۳۵۵ (albumin weight) and for external quality traits of eggs in the range from ۰.۲۶۱ (shell strength) up to ۰.۳۳۲ (Shell weight). Also, the mean genetic correlation estimates between growth traits, and between reproductive traits ranged from ۰.۲۹۷ to ۰.۸۷۸ and -۰.۶۷۸ to ۰.۷۸۸, respectively. Also, the genetic correlation between internal and external quality traits of eggs ranged from -۰.۰۶۹ to -۰.۹۷۹ and -۰.۰۱۲ to -۰.۸۵۶, respectively. The estimates reported in the present study are appropriate to be used in breeding programs when reliable genetic parameter estimates are not accessible for economically important traits in native fowls.

Keywords:

Fowls , Heritability , Genetic correlation , Performance traits , Systematic review