Effect of Bt-cottonseed meal feeding on intake, growth, nutrient utilization, serum cholesterol, immunological status, organ weight and slaughtering performance of growing lambs

This experiment studied feeding value of conventional and Bt cottonseed meal as replacement of groundnut oil meal for the feeding of lamb (90±5 day of age; 15.5±0.89 kg). Diet fed to control lambs contained meal of groundnut oil cake as source of CP while other two groups received diet containing either conventional cottonseed meal (CSM) or Bt-cottonseed meal (Bt-CSM) at 18% level. Total and average daily BW gain, feed intake and its conversion efficiency were similar among groups. However, Bt-CSM diet fed lambs had ADG (111g/day) and feed efficiency (8.0 kg feed/kg gain) than CSM lambs (89 g and 9.1, respectively). DM intake ranged from 706 to 861 g, which was similar among groups, but Bt-CSM diet fed lambs had higher DMI by 8.6 per cent. Intake and digestibility of OM, CP and NDF were similar, whereas CSM diet fed lambs had higher digestibility of ADF (P=0.022), and cellulose (P=0.002). N intake, excretion and balance were similar among groups. Excretion of allantoin in urine was higher in Bt-CSM diet fed lambs. Urinary PD excretion and MCP synthesis was higher by 23.3 and 37%, respectively, in Bt-CSM diet fed lamb compared to CSM lambs. Total cholesterol was higher in Bt-CSM diet fed lambs. Serum IgG level, carcass characteristics and organ weights were not different. Feeding of Bt-CSM improved average daily gain by 24%, feed efficiency by 13.8% and microbial crude protein synthesis by 37% to that of conventional CSM, while digestibility, nitrogen utilization, immune status, slaughtering performance and organs weight did not change. Therefore, genetically modified cottonseed can be used in lamb feeding in replacement of conventional cottonseed or groundnut oil meal as protein supplement up to 18% for mutton production.