Gossypol was not detected in the longissimus muscle of lambs fed several forms of cottonseed

The aim of this work was to evaluate the growth performance, carcass characteristics, 12th rib tissue composition, haematological and serum biochemical parameters, as well as the presence of gossypol residues in the meat of Santa Inês lambs fed cotton crop by-products. For an experimental period of 90 days, 24 intact male Santa Inês lambs (bodyweight (BW): 20.6 ± 1.9 kg; 4 months old) were fed a 50:50 forage:concentrate diets fed ad libitum. Chopped Coast cross (Cynodon dactylon (L.) Pers) hay was used as forage. The animals were then allocated into four treatments, according to the cotton crop by-product included in the concentrate formulation: Control (CON) – No cotton crop by-product used in formulation; Whole cottonseed (WCS); Cottonseed cake (CSC); and Cottonseed meal (CSM). The animals were weighed and blood collected every 15 days. At the end of the experimental period, the lambs were slaughtered and the evaluations of carcass characteristics, 12th rib tissue composition and presence of gossypol residues in the meat were carried out. Dry matter intake was higher (P < 0.05) for the diets containing cotton crop by-products, but BW gains were not different (P > 0.05). Despite these results the animals fed the highest level of gossypol (WCS) had lower (P < 0.05) carcass yield resulting in lower (P < 0.05) carcass weight, suggesting a possible negative effect of gossypol on carcass development. Serum urea was elevated on all treatments including CON, otherwise haematological and biochemical parameters were within reference ranges. No gossypol residues in meat were detected by the method used here, which had a minimum detection limit of 20 ppb. It is concluded that the cotton crop by-products may have impaired carcass production but did not leave gossypol residues in lamb meat.