Tipton Jessie E, Lewis Linda K, Ricks Ralph E, Maresca Sebastian, Valiente Sebastian Lopez, Long Nathan M
Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634, USA.
Cuenca del Salado Experimental Station, National Institute of Agricultural Technology, Rauch, Buenos Aires BA 7203, Argentina.
Animals (Basel). 2020 Oct 6;10(10):1819. doi: 10.3390/ani10101819.
The objective of this study was to determine how weaning age, days on supplements, and lipid supplementation affected the growth and marbling deposition of steers. Steers from a single sire were early weaned (n = 24) at 150 ± 11 days of age or traditionally weaned (n = 24) at 210 ± 11 days of age. Steers were assigned to control (n = 12/weaning group) or an isocaloric, isonitrogenous rumen by-pass lipid (RBL, n = 12/weaning group) for either 45 (n = 6/treatment) or 90 (n=6/treatment) days then harvested. Steer body weight (BW) was recorded on days -14 and -7, then BW and blood samples were collected on days 0, 22, 45, 66, and 90. The right rib section of each animal was collected for proximate analysis. from RBL steers had increased lipids compared with control steers (3.6 ± 0.2 vs. 2.4 ± 0.2% on a wet basis; < 0.0001). Steers fed for 90 days had greater ( = 0.02) concentrations of lipid (3.3 ± 0.2%) than those fed for 45 days (2.7 ± 0.2%). There was a weaning age by treatment by days on feed interaction for intramuscular adipocyte diameter ( = 0.02) in which early weaned RBL fed for 90 days steers had an increased adipocyte diameter compared to the early weaned control fed for 90 and early weaned fed for 45 days steers with all other treatment groups as intermediates. Supplementation of RBL increased concentrations of C18:2, C20:4, and total fatty acids on days 45 and 90 ( ≤ 0.05). Data show that RBL supplementation increased the marbling content of the . Furthermore, a longer period of supplementation resulted in increased adipose diameter.
本研究的目的是确定断奶年龄、补饲天数和脂肪补充对阉牛生长和大理石花纹沉积的影响。来自单一父系的阉牛在150±11日龄时进行早期断奶（n = 24），或在210±11日龄时进行传统断奶（n = 24）。阉牛被分为对照组（n = 12/断奶组）或等热量、等氮的瘤胃旁路脂肪组（RBL，n = 12/断奶组），分别饲喂45天（n = 6/处理）或90天（n = 6/处理），然后进行屠宰。在第-14天和-7天记录阉牛体重（BW），然后在第0、22、45、66和90天采集BW和血样。采集每只动物的右侧肋骨部分进行近似分析。与对照阉牛相比，RBL阉牛的脂质含量增加（湿基下分别为3.6±0.2%和2.4±0.2%；P<0.0001）。饲喂90天的阉牛的脂质浓度（3.3±0.2%）高于饲喂45天（2.7±0.2%）的阉牛（P = 0.02）。对于肌内脂肪细胞直径，存在断奶年龄×处理×补饲天数的交互作用（P = 0.02），其中早期断奶且饲喂90天的RBL阉牛的脂肪细胞直径大于早期断奶且饲喂90天的对照阉牛以及早期断奶且饲喂45天的阉牛，所有其他处理组介于两者之间。在第45天和90天，补充RBL可提高C18:2、C20:4和总脂肪酸的浓度（P≤0.05）。数据表明，补充RBL可增加阉牛的大理石花纹含量。此外，较长的补饲期会导致脂肪直径增加。
