Bharanidharan Rajaraman, Thirugnanasambantham Krishnaraj, Ibidhi Ridha, Bang Geumhwi, Jang Sun Sik, Baek Youl Chang, Kim Kyoung Hoon, Moon Yea Hwang
Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.
Department of Eco-Friendly Livestock Science, Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Korea.
Animals (Basel). 2021 Nov 25;11(12):3378. doi: 10.3390/ani11123378.
The present study evaluated the influence of dietary protein level on growth performance, fatty acid composition, and the expression of lipid metabolic genes in intramuscular adipose tissues from 18- to 23-month-old Hanwoo steers, representing the switching point of the lean-to-fat ratio. Forty steers with an initial live weight of 486 ± 37 kg were assigned to one of two treatment groups fed either a concentrate diet with 14.5% CP and or with 17% CP for 6 months. Biopsy samples of intramuscular tissue were collected to analyze the fatty acid composition and gene expression at 23 months of age. Throughout the entire experimental period, all steers were restrained twice daily to allow individual feeding. Growth performance, blood metabolites, and carcass traits, according to ultrasonic measurements, were not affected by the experimental diets. The high-protein diet significantly increased the expression of intramuscular ( < 0.1) and ( < 0.05) but did not affect genes involved in fatty acid uptake ( and ) nor lipogenesis (, , and ). In addition, it downregulated intramuscular ( < 0.01) related to lipogenesis but also ( = 0.001), ( = 0.016), and ( = 0.057), which are involved in fatty acid esterification and adipocyte size. Hanwoo steers fed a high-protein diet at 18-23 months of age resulted in a relatively lower lipid turnover rate than steers fed a low-protein diet, which could be responsible for shortening the feeding period.
本研究评估了日粮蛋白质水平对18至23月龄韩牛阉牛生长性能、脂肪酸组成以及肌内脂肪组织中脂质代谢基因表达的影响，这一阶段代表了瘦肉率与脂肪率的转换点。40头初始体重为486±37千克的阉牛被分配到两个处理组之一，分别饲喂含14.5%粗蛋白或17%粗蛋白的精料日粮6个月。在23月龄时采集肌内组织活检样本，以分析脂肪酸组成和基因表达。在整个实验期间，所有阉牛每天两次被限制活动以进行个体饲喂。根据超声测量，生长性能、血液代谢物和胴体性状不受实验日粮的影响。高蛋白日粮显著增加了肌内（<0.1）和（<0.05）的表达，但不影响参与脂肪酸摄取（和）及脂肪生成（、和）的基因。此外，它下调了与脂肪生成相关的肌内（<0.01），以及参与脂肪酸酯化和脂肪细胞大小的（=0.001）、（=0.016）和（=0.057）。18至23月龄饲喂高蛋白日粮的韩牛阉牛，其脂质周转率相对低于饲喂低蛋白日粮的阉牛，这可能是缩短育肥期的原因。
