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The aim of the experiment was to investigate the effect of dietary protein level on growth performance, serum immune indexes, antioxidant indexes, rumen fermentation parameters and microflora composition of Angus calves after weaning. Eighteen weaned calves at 90 days of age with good health and similar body weight were randomly divided into three groups (half male and half female) with six replicates per group and one cow per replicate. Calves in experimental groups were fed diets with high protein (19.65% protein, 5.74 MJ/kg net energy, T group), medium protein (18.60% protein, 5.62 MJ/kg net energy, S group) and low protein (17.76% protein, 5.40 MJ/kg net energy, F group), respectively. The experiment lasted for 100 d. The results showed that high protein level diet significantly increased body weight and average daily gain of calves at 120 days of age and 180 days of age ( P<0.05). Compared with S group, the content of IgA and IgM, the activity of SOD and T-AOC in serum of calves in T group were significantly increased ( P<0.05), and the content of TNF- α was significantly decreased ( P<0.05). The content of acetic acid, propionic acid, isobutyric acid and valeric acid in the rumen of T group were increased ( P<0.05). The rumen bacterial diversity index of T group was significantly increased ( P<0.05), and Firmicutes and Bacteroidetes were the dominant bacterial groups. The study indicates that high protein level diet can significantly promote the growth performance and rumen fermentation function of calves, and is beneficial to rumen development of calves. [ABSTRACT FROM AUTHOR]

试验旨在研究饲粮蛋白水平对哺乳期安格斯犊牛生长性能、血清生化、免疫与抗氧化指标的影响。 选取体重（36.0±1.5） kg、出生日龄相近的安格斯犊牛30 头, 随机分为3 组, 每组10 个重复, 每个重复1 头牛, 公、母各半。试验犊牛分别饲喂高蛋白水平（22%）、中蛋白水平（20%） 和低蛋白水平（18%） 饲粮。犊牛7 d 开 始补饲颗粒料, 预试期10 d, 正式试验期90 d。结果显示：50 日龄, 高蛋白组犊牛体重极显著高于低蛋白组 （P<0.01）, 显著高于中蛋白组（P<0.05）;90 日龄, 高蛋白组犊牛体重极显著高于中、低蛋白组（P<0.01）, 高蛋 白组犊牛日增重显著高于中、低蛋白组（P<0.05）, 料重比显著低于中蛋白组（P<0.05）。高蛋白组犊牛血清总蛋 白（TP） 含量显著高于中蛋白组（P<0.05）, 极显著高于低蛋白组（P<0.01）;谷草转氨酶（AST） 活性极显著低 于低蛋白组（P<0.01）, 显著低于中蛋白组（P<0.05）;血糖（GLU） 含量显著高于中、低蛋白组（P<0.05）;尿 素氮（BUN） 含量显著高于中蛋白组（P<0.05）, 极显著高于低蛋白组（P<0.01）。高蛋白组犊牛血清免疫球蛋白 E （IgE） 含量显著高于中蛋白组（P<0.05）, 极显著高于低蛋白组（P<0.01）;免疫球蛋白G （IgG） 含量极显著高 于中、低蛋白组（P<0.01）;高蛋白组白细胞介素-10 （IL-10）、肿瘤坏死因子-α （TNF-α） 含量显著低于中、 低蛋白组（P<0.05）。高蛋白组犊牛血清谷胱甘肽过氧化物酶（GSH-Px） 活性极显著高于中、低蛋白组 （P<0.01）;丙二醛（MDA） 含量极显著低于中、低蛋白组（P<0.01）, 中蛋白组MDA 含量显著低于低蛋白组 （P<0.05）。高蛋白组犊牛血清甲状腺素（T4）、生长激素（GH） 含量显著高于中、低蛋白组（P<0.05）, 高蛋白 组犊牛发病率极显著低于中、低蛋白组（P<0.01）, 中蛋白组犊牛发病率显著低于低蛋白组（P<0.05）。研究表 明, 综合哺乳期安格斯犊牛日增重、血清生化、免疫、抗氧化指标等各方面因素考虑, 22% 蛋白水平的饲粮对犊 牛最为合适. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to further study the causes of calf blindness aud provide theoretical support for reducing the incidence of congenital blindness of calves aud reducing the economic losses of the breeding industry. [ Method] A cattle farm was selected in Ningxia, whose birth date was close to that of blind calves aud their mothers, aud normal calves. Blood and plasma samples were collected. Through metabonomic aualysis, the differential metabolites and pathway changes between blind calves and their mothers, aud normal calves were studied. [Result] The VIP value of OPLS-DA > 1 and the univariate statistical aualysis P < 0. 05 were used as the criteria for significautly different metabolites. A total of 256 different metabolites were screened from the comparison group of blind calves and normal calves ( V aS. vs. VaL), including 144 in the positive ion mode and 112 in the negative ion mode. A total of 177 different metabolites were screened from the comparison group between the blind calf aud its mother ( VaS. vs. CS), including 108 in the positive ion mode aud 69 in the negative ion mode. The content of rhodopsin in the blind calf was significantly lower than that of its mother, with log2 FC reaching - 2. 87. Compared with its mother, there were 30 differential metabolic pathways with P < 0. 05 in total in blind calves, and 10 differential metabolic pathways with corrected P < 0. 05 in total. Among them, bile secretion metabolic pathway had the largest distribution of differential metabolites. Compared with its mother, 4 metabolites in blind calves were significantly up-regulated, and 9 metabolites were significantly down-regulated. Compared with normal calves, there were 12 differential metabolic pathways with P <0. 05 in total in blind calves, and 16 differential metabolic pathways with corrected P < 0. 05 in total. Among them, bile secretion metabolic pathway distributed the most differential metabolites. Compared with normal calves, there were 5 metabolites significantly up-regulated and 4 metabolites significantly down-regulated in blind calves. [ Conclusion] The bile secretion metabolic pathway of blind calves is significantly different from that of their mothers and normal calves. The research suggests that the blindness of calves may be a disease of the body living in the liver, affecting the normal secretion of bile, leading to that the normal intake of fat-soluble vitamin A can not be absorbed and utilized, and thus affecting the vision of calves. In addition, compared with their mothers, the content of rhodopsin, which affects the cascade reaction of light transduction, is significantly down-regulated under the condition that there is no significant difference in vitamin A levels in the body of blind calves. The study suggests that the mutation of rhodopsin gene (RHO) encoding rhodopsin protein and the lack of rhodopsin protein might be another reason for their blindness. [ABSTRACT FROM AUTHOR]

[Objective] The paper aimed to study t he regulatory effect of Lycium barbarum glycopeptide (LbGp) on the immunosuppression induced by cyclophosphamide (CY) in chicks.[Method] 200 of 7 days Highland layers were selected and divided into 5 groups randomly : blank group (NC), cyclophosphamide grou p (CY) and high dose of LbGp (LbGpH), middle (LbGpM) and l ow dose of (LbGpL ) groups. The layers of NC group were received normal saline intramuscularly, the layers of the other 4 groups were injected intramuscularly with 80 mg/ (kg · d ) CY for 3 days to building immunosuppression modeling. After that, the l ayers of LbGpH, LbGpM and LbGpL grou ps were given 10, 5, 2. 5 mg/ (kg · d ) of LbGp respectively for 7 days. On t he 7, 14, 21, and 28 days after the first administration, 5 chicks were randomly sel ected to determine their body weight, spleen index, peripheral bl ood lymphocyte transformation, and spleen histological analysis.[Result] LbGpH significantly increased the body weight of CY-induced immunosuppressive chicks (P < 0. 05 ), the LbGpM significantly increased the body weight of CY-induced immunosuppressive chicks (P < 0. 01 ) ; The LbGpM significantly increased the spleen index of CY-induced immunosuppressive chicks (P < 0. 05); The LbGpH and LbGpM significantly increased the peripheral blood lymphocyte transformation rate of CY-induced immunosuppressive chicks (P < 0. 01); The histological results of the spleen showed that the number of germinal centers in each LbGp group was significantly higher t han t hat in the CY group on t he 14th and 21th day after t he first administration (P < 0. 05) .[Conclusion] L. barbarum glycopeptide has a significant antagonistic effect on the immunosuppression of chicks induced by cyclophosphamide, and the middle dose group has the best effect. [ABSTRACT FROM AUTHOR]