Carcass traits and fatty acid profile of meat from lambs fed different cottonseed by-products

Abstract The aim of this study was to evaluate the changes in carcass traits and fatty acid profile of meat by feeding lambs with cottonseed by-products. Twenty-four 5-month old ram lambs received one of four diets: 19.5% of dry matter intake (DMI) of whole cottonseed (WCS), 19.5% DMI cottonseed meal (CSM), 19.5% DMI high oil cottonseed meal (CSC) and a control group (CTL) without cottonseed by-products. After 95 experimental days, the lambs were slaughtered. Carcass weight and 12th rib composition (chemical and centesimal) were measured. Samples of Longissumus dorsi muscle were taken for fatty acid profile analysis. The animals that received CSM showed higher hot carcass weight, carcass yield and rib eye area than animals from the WCS group. Meat from CSM and CSC groups had higher levels of conjugated linolenic acid (CLA) than others and yet CSC group showed higher vaccenic acid than others. Meat from animals that received whole cottonseed had less unsaturated fatty acids, CLA and vaccenic acid. Therefore, processed cottonseed by-products (CSM and CSC) should be preferred for use in ruminant feed over whole cottonseed. The meat from animals that did not receive cotton by-products had higher n-3 fatty acids, and also better n-6 to n-3 ratio compared to others, which may indicate a problem in using these products in ruminant nutrition due to current importance given to these fatty acids in human nutrition.