1106
Fatty acid profile and oxidative stability of carcass fat from meat goats fed grass-legume forage diets
A series of experiment was conducted at the Caprine Research and Education Unit at Tuskegee University to develop and demonstrate a profitable and sustainable forage-based goat production system with 6 different forage combinations included annual ryegrass (RG) or RG + legume combinations (e.g. Austrian pea (AP), berseem clover (BC), hairy vetch (HV), RG+AP+HV, and RG+HV+AP+BC)) in the winter of 2011 for the Southeastern U.S. Forty-eight crossbred goats (Capra hircus; BW= 27.46 kg) were randomly assigned to 12 paddocks with 6 forage combinations with 2 replicates (n = 4) during 45 days. After grazing ended, goats were transported to Mississippi State University Meat lab and were slaughtered according to the USDA guidelines and carcass characteristics were determined. Forage biomass and forage chemical composition were measured from February to May. On each occasion four random quadrates (0.25 m2) per forage paddock were cut using a hand-clipper. There was a forage sampling time x forage combination interaction (P<0.01) for CP and NDF. Forage CP content was higher in March than February and April, but NDF content continuously increased with time. The RW with HV combinations continued to have greater CP content. Animals on RG and BC combinations grew 18% faster and reached expected slaughter weight in less time when compared to RG pasture system. Goats grazing RG+BC and RG+HV+AP had higher (P<0.05) ADG and carcass weights than other forage combinations. Goats grazed on RG-based diet had higher SFA and polyunsaturated fatty acids (PUFA) in intramuscular fats (P<0.01), but were lower in mescenteric kidney fat and subcutaneous fat (P<0.05) compared to legume forage-based diets, respectively. For goats grazing on RG-based diet had significantly higher (P<0.05) omega-3 and omega-6 fatty acids in intramuscular fat content, but were lower in subcutaneous fat (P<0.05) compared to legume forage-based diets. Mono unsaturated fatty acids (MFA) were not affected by diets. These results indicated that goats receiving RG forage-based diets produced carcasses with more PUFA and higher omega-3 and -6 fatty acids in intramuscular fat from Kiko-crossbred male goats.
Keywords: fatty acids; goats; grass, legume