Research note: effects of hyperpigmentation of the visceral peritoneum on body weight and selection method in Chinese yellow-feathered broilers.

We previously identified a dark blue appearance through the skin of abdomen, especially the colored chicken breeds, called hyperpigmentation of the visceral peritoneum (HVP) which characterized by intense pigmentation of connective tissue in the visceral peritoneum. The HVP has recently garnered increasing attention due to its negative impact on carcass appearance, and been an important concern in the poultry industry, especially for the Chinese yellow-feathered broilers. In this study, we measured the in vivo HVP at different time points, and analyzed the correlation between the HVP in vivo and postmortem. Then, established an accurate and reliable HVP phenotypic measuring method in vivo for early selection in chickens and analyzed the association of phenotypic variations with the in vivo HVP traits with growth traits. The results showed that the in vivo HVP at 21 d of age in chickens have a high heritability (h2 = 0.452) through estimating genetic parameters, and in vivo HVP levels at 21 and 42 d were both significantly associated with those postmortem in chickens, suggesting that directional selection on reducing HVP can be implemented as early as at 21 d in the breeding and production of chickens. Although, we found HVP had no effect on the body weight at 1 d, it could significantly reduce the body weight at 21, 42, 70 d and 91 d in chickens. This suggests HVP not only has a negative effect on carcass traits, but also significantly reduces the production in the poultry industry.