Effects of Myostatin Mutation on Onset of Laying, Egg Production, Fertility, and Hatchability

SIMPLE SUMMARY: Poultry can be classified as broilers for meat production and layers for egg production. Modern poultry farming improved economically important traits of broilers and layers by breeding and genetic selection. Myostatin (MSTN) has gained attention as a potential selection marker for higher meat production in the poultry industry, because MSTN mutant chickens and quail showed increased muscle mass. In this study, the effect of MSTN mutation on egg production was investigated to evaluate potential use of MSTN for higher egg production in the layer industry. MSTN homozygous mutant quail showed a significantly delayed onset of egg laying, a higher egg weight, and a lower number of eggs produced during the active laying period compared to wild-type quail. However, there were no significant differences in total egg production for 20 days, percentage proportion of egg white and yolk in egg weight, and egg fertility, and hatchability between MSTN mutant and WT quail. Although a clear benefit on egg production by MSTN mutation in quail was not revealed, this study provided useful information to understand the productive performance of MSTN mutant hens. ABSTRACT: Increased body weight and muscle mass, along with improved feed efficiency, by myostatin (MSTN) mutation in quail, supports the potential use of MSTN as a selection marker for higher meat yield in the poultry industry. Although economically important traits of broilers have been studied using recently generated MSTN mutant quail, the effect of MSTN mutation on egg production has not yet been investigated. In this study, several economically important traits of layers, including egg production, reproduction, and body composition of hens, were compared between MSTN homozygous mutant, heterozygous mutant, and wild-type (WT) quail. In terms of egg production, MSTN homozygous mutant quail, showing significantly delayed onset of egg laying, laid significantly heavier eggs, but a significantly lower number of eggs compared to WT quail for 20 days after 3 months of age, resulting in similar total egg production among groups. In addition, the percentage proportion of egg white and yolk in egg weight were similar among groups. Furthermore, similar fertility and hatchability of eggs from MSTN homozygous mutant breeding pairs and WT breeding pairs indicated normal reproductive function of MSTN mutant quail. These findings will provide scientific rationales for the consideration of MSTN as a potential selection marker for layers in the poultry industry.