Processing Losses, Carcass Quality, and Meat Yields of Broiler Chickens Receiving Diets Marginally Deficient to Adequate in Lysine Prior to Marketing

Abstract

A feed based on com, soybean meal, and sesame meal containing .85% lysine was supplemented with L-lysine HCl to provide .95 and 1.05% of total lysine. Each lysine level was given to broilers from 28 to 42 days of age in which the sexes were reared separately. No differences occurred in BW because of lysine, but feed conversion decreased as the lysine level increased. The holding loss prior to slaughter was greater with the birds that had received .95% lysine versus those that had received .85 and 1.05% lysine, respectively; however, no effects were detected on the chilled-carcass yield after processing. The extent of carcass finish increased as the lysine decreased. The fat content of the whole chilled carcass increased along with finish, while protein and ash were to the reverse. The percentage of fat in the skin and in the thigh meat were altered in parallel with the whole carcass, but the breast meat was unaffected. Cutting sample carcasses into commercial parts revealed that the proportions of breast and thigh increased with lysine at the expense of back both on a raw and a cooked basis. The cooked meat from the breast, wings, and back increased, the skin decreased. Both sexes responded similarly to lysine.