There was organized a 2×2 factorial type experience in which it has been aimed the influence of forage/concentrates ratio and the effect of supplementing the ratio with full fat soya by-pass （FFS） on the produc...There was organized a 2×2 factorial type experience in which it has been aimed the influence of forage/concentrates ratio and the effect of supplementing the ratio with full fat soya by-pass （FFS） on the production performance and carcass fatty acid profile of fattening lambs. 32 Tsigai lambs were divided into 4 groups and were fed with 2 different diets regarding the forage/concentrates ratio （35/65 and 65/35, on a DM basis）, containing or not 5% FFS （full fat soya treated with formaldehyde 12.5%）. Including FFS in diet and the ratios rich in concentrates determined a significant improvement in weight gain （P〈0.01）, in the degree of food recovery and in fatty acid profile from the carcass. It has been significantly increased （P〈0.01） the weight of polyunsaturated fatty acids （PUFA） from intramuscular fat （longissimus dorsi-LD and femoral biceps-FB） and the deposit fat （subcutaneous-SC and perirenal-PR） and decreased the proportion of saturated （SFA） and monounsaturated fatty acids （MUFA）. Most significant differences were recorded about PUFA from Omega-3 series （C18：3 n-3, EPA C22：3 n-3, DPA and DHA） and CLA isomers （conjugated linolenic acid： C 18：2 C9, tl I＋C 18：2 t10, C 12）. The best profile of fatty acids, considered in light of the influence on human health （high concentration of Omega 3 fatty acids and CLA and low in SFA） was established in LD, for lambs fed with diets high in concentrates and which contained FFS （HC/S）.展开更多
Management intensity critically influences the productivity and sustainability of pasture systems through modifying soil microbes, and soil carbon （C） and nutrient dynamics; however, such effects are not well unders...Management intensity critically influences the productivity and sustainability of pasture systems through modifying soil microbes, and soil carbon （C） and nutrient dynamics; however, such effects are not well understood yet ir the southeastern USA. We examined the effects of grazing intensity and grass planting system on soil C and nitrogen （N） dynamics, and microbial biomass and respiration in a long-term field experiment in Goldsboro, North Carolina, USA. A split-plot experiment was initiated in 2003 on a highly sandy soil under treatments of two grass planting systems （ryegrass rotation with sorghum-sudangrass hybrid and ryegrass seeding into a perennial bermudagrass stand） at low and high grazing densities. After 4 years of continuous treatments, soil total C and N contents across the 0 30 cm soil profile were 24.7% and 17.5% higher at the high than at the low grazing intensity, likely through promoting plant productivity and C allocation belowground as well as fecal and urinary inputs. Grass planting system effects were significant only at the low grazing intensity, with soil C, N, and microbial biomass and respiration in the top 10 cm being higher under the ryegrass/bermudagrass than under the ryegrass/sorghum-sudangrass hybrid planting systems. These results suggest that effective management could mitigate potential adverse effects of high grazing intensities on soil properties and facilitate sustainability of pastureland.展开更多
文摘There was organized a 2×2 factorial type experience in which it has been aimed the influence of forage/concentrates ratio and the effect of supplementing the ratio with full fat soya by-pass （FFS） on the production performance and carcass fatty acid profile of fattening lambs. 32 Tsigai lambs were divided into 4 groups and were fed with 2 different diets regarding the forage/concentrates ratio （35/65 and 65/35, on a DM basis）, containing or not 5% FFS （full fat soya treated with formaldehyde 12.5%）. Including FFS in diet and the ratios rich in concentrates determined a significant improvement in weight gain （P〈0.01）, in the degree of food recovery and in fatty acid profile from the carcass. It has been significantly increased （P〈0.01） the weight of polyunsaturated fatty acids （PUFA） from intramuscular fat （longissimus dorsi-LD and femoral biceps-FB） and the deposit fat （subcutaneous-SC and perirenal-PR） and decreased the proportion of saturated （SFA） and monounsaturated fatty acids （MUFA）. Most significant differences were recorded about PUFA from Omega-3 series （C18：3 n-3, EPA C22：3 n-3, DPA and DHA） and CLA isomers （conjugated linolenic acid： C 18：2 C9, tl I＋C 18：2 t10, C 12）. The best profile of fatty acids, considered in light of the influence on human health （high concentration of Omega 3 fatty acids and CLA and low in SFA） was established in LD, for lambs fed with diets high in concentrates and which contained FFS （HC/S）.
基金Supported by the USDA-NRI,USA(No.NRI-2007-03307)the USDA Southern Region SARE Program,USA(No.2012-02978)+2 种基金the China Scholarship Council(No.[2006]3085)the National Natural Science Foundation of China(No.41201259)the Natural Science Foundation of Shaanxi Province,China(No.2013JQ5001)
文摘Management intensity critically influences the productivity and sustainability of pasture systems through modifying soil microbes, and soil carbon （C） and nutrient dynamics; however, such effects are not well understood yet ir the southeastern USA. We examined the effects of grazing intensity and grass planting system on soil C and nitrogen （N） dynamics, and microbial biomass and respiration in a long-term field experiment in Goldsboro, North Carolina, USA. A split-plot experiment was initiated in 2003 on a highly sandy soil under treatments of two grass planting systems （ryegrass rotation with sorghum-sudangrass hybrid and ryegrass seeding into a perennial bermudagrass stand） at low and high grazing densities. After 4 years of continuous treatments, soil total C and N contents across the 0 30 cm soil profile were 24.7% and 17.5% higher at the high than at the low grazing intensity, likely through promoting plant productivity and C allocation belowground as well as fecal and urinary inputs. Grass planting system effects were significant only at the low grazing intensity, with soil C, N, and microbial biomass and respiration in the top 10 cm being higher under the ryegrass/bermudagrass than under the ryegrass/sorghum-sudangrass hybrid planting systems. These results suggest that effective management could mitigate potential adverse effects of high grazing intensities on soil properties and facilitate sustainability of pastureland.
