Abstract This study investigated the effects of dietary protein levels on growth, carcass characteristics, serum biochemical index, and meat quality of Hu male lambs. Sixty lambs were randomly divided into 5 groups with 12 lambs in each group. The protein levels of the five diets were: 125 g/kg, 132 g/kg, 140 g/kg, 148 g/kg, and 156 g/kg. Fifteen lambs were slaughtered at the end of 70-d feeding experiment. Lambs fed 140 g/kg protein level diet had highest ADG (p = 0.058), and had lowest FCR (p = 0.079). The concentration of blood urea nitrogen (BUN) in 140g/kg protein level group was significantly higher than that in other groups (p = 0.002). The proportion of non-carcass fat ratio (p = 0.007), perirenal fat ratio (p = 0.013), heart (p = 0.023), and the proportion of mesenteric fat ratio (p = 0.074) linearly decreased with the increase of dietary protein level. The concentrations of blood glucose (GLU), triglyceride (TG), high density lipoprotein cholesterol (HDL) in serum linearly decreased, and dietary protein was associated with quadratic decreases in lactic acid (LACT) (p = 0.018). Furthermore, the dietary protein levels had significant effects on amino acid, and fatty acid profiles of the longissimus lumborum (LL) muscle. Particularly the saturated fatty acids (SFAs) (p

中文翻译：

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日粮蛋白质水平对胡公羊生长、胴体特性、血清生化指标及肉质的影响

摘要 本研究调查了日粮蛋白质水平对胡公羊生长、胴体特征、血清生化指标和肉质的影响。60只羊随机分为5组，每组12只。五种饮食的蛋白质水平为：125 g/kg、132 g/kg、140 g/kg、148 g/kg和156 g/kg。70天饲养试验结束时屠宰羔羊15只。饲喂 140 g/kg 蛋白质水平日粮的羔羊具有最高的 ADG (p = 0.058) 和最低的 FCR (p = 0.079)。140g/kg蛋白水平组血尿素氮（BUN）浓度显着高于其他组（p=0.002）。非胴体脂肪比例（p = 0.007）、肾周脂肪比例（p = 0.013）、心脏（p = 0.023）、肠系膜脂肪比例（p = 0. 074)随着日粮蛋白质水平的增加而线性下降。血清中血糖 (GLU)、甘油三酯 (TG)、高密度脂蛋白胆固醇 (HDL) 的浓度呈线性下降，膳食蛋白质与乳酸 (LACT) 的二次下降有关 (p = 0.018)。此外，膳食蛋白质水平对腰最长肌 (LL) 的氨基酸和脂肪酸谱有显着影响。特别是饱和脂肪酸 (SFA) (p 和腰最长肌 (LL) 肌肉的脂肪酸谱。特别是饱和脂肪酸 (SFA) (p 和腰最长肌 (LL) 肌肉的脂肪酸谱。特别是饱和脂肪酸 (SFA) (p