Genetic and Phenotypic Association Between Skin Tearing and Skin Collagen, Protein, and Fat in Broilers

Abstract

Two crosses of meat-type chickens, selected divergently for low (LF) or high (HF) abdominal fat, and a commercial broiler cross (CM) were studied. Protein, collagen, and fat content were determined in skin biopsies taken from 30 random 6-wk-old live males and females from each cross. Skin tears following cold-water plucking and protein, collagen, and fat content in breast skin samples were determined at 7 wk of age for another 70 chickens per cross. In each cross, about 100 female offspring of the chickens sampled for biopsies were also scored for skin tears and the composition of their breast skin samples.Intact skin was associated with higher collagen and total protein contents and possibly lower fat. Skin of LF cross chickens had lower fat and higher protein and collagen contents and 50% lower incidence of skin tears, as compared with that of HF and CM chickens. Based on parent-offspring correlations, heritability estimates of .35 to .47 were obtained for protein content, collagen content, and collagen:fat ratio. Protein and collagen content in the parents’ skin samples were negatively correlated (r values around −.5) with incidence of skin tears among their offspring, whereas a positive correlation (.44) was found with fat content. No correlation was found between offspring’s skin tears and parents’ body weights. It is concluded that incidence of skin tears could be reduced by selection on collagen or fat content (or both) of breast skin biopsies taken from live birds, with expected concomitant improvement in carcass leanness.