为了确定去势对生长性能的影响,血清激素水平,盲肠微生物群组成,和牛体内的代谢产物.共有18头荷斯坦公牛和牛被分为公牛和牛小组,并随机分配到3个围栏(每个围栏3头牛,每头牛用栅栏隔开)来确定平均日增重(ADG),每日干物质摄入量(MDI),和饲料效率(G/F)。审判结束后,每组6头牛被随机宰杀。收集血清以测量激素浓度,收集盲肠内容物以测量pH值,短链脂肪酸,和消化酶活性。宏基因组测序和非靶向代谢组学用于研究微生物群组成,功能概况,和盲肠内容物的不同代谢物。我们发现去势显著降低ADG,QI,牛的G/F(P<0.05)。血清睾酮,甲状腺素,生长激素(P<0.05),与公牛组相比,转向组的三碘甲状腺原氨酸(P<0.01)浓度显着降低。纤维素酶的活性,木聚糖酶,果胶酶,和β-葡萄糖苷酶显著降低(P<0.05),而脂肪酶和α-淀粉酶的活性显着增加。此外,去势显着降低了反刍动物科细菌的相对丰度,螺旋体_卟啉,Oscillibacter_sp。(P<0.05),和Alistipes_senegalensis(P<0.01),而Phocaeicola_plebeius的相对丰度显着增加(P<0.05)。此外,Phocaeicola_plebeius的相对丰度与睾酮水平呈负相关,盲肠微生物群的功能在牛GH29和GH97家族中得到了丰富。代谢组学分析表明,去势增加了L-缬氨酸的水平,L-苯丙氨酸,L-天冬氨酸,L-异亮氨酸,L-赖氨酸,蛋氨酸,L-谷氨酸,和L-亮氨酸,同时通过2-氧代羧酸代谢途径降低α-酮戊二酸的水平。此外,α-酮戊二酸与Oscillibacter_sp呈负相关。(P<0.01)。总的来说,去势可以通过改变盲肠微生物群的组成来抑制牛的生长。因此,本研究为提高母牛生长绩效提供了理论和实践依据。
在美国,雄牛的阉割是一种常规管理做法。它提高了牛肉的质量等级和嫩度,和牛比完整的雄性有更理想的肉质。因此,它是为了满足人类对优质肉类的需求而进行的。然而,阉割减少了牛的身体和屠体重量,导致喂养成本增加。因此,研究母牛的减肥机理,为今后提高母牛的生长提供理论依据,具有重要意义。我们的结果发现,去势降低了血清中的睾酮和生长激素浓度,改变了盲肠微生物组成和功能,尤其是降低了反刍动物科细菌和镰刀菌的相对丰度。盲肠微生物群的这些变化降低了降解纤维素和半纤维素的消化酶的活性,并降低了代谢物α-酮戊二酸的水平,因此,抑制引导增长。因此,盲肠微生物群可能影响母牛的生长性能,为改善母牛的生长提供理论和实践依据。
To determine the effects of castration on growth performance, serum hormone levels,
cecal microbiota composition, and metabolites in cattle. A total of 18 Holstein bulls and steers were divided into bull and steer groups and randomly assigned to 3 pens (3 cattle per pen, and each cattle were separated by a fence) to determine the average daily gain (ADG), daily dry matter intake (DMI), and feed efficiency (G/F). After the finishing trial, six cattle per group were randomly slaughtered. Serum was collected to measure the hormone concentration, and the
cecal content was collected to measure the pH, short-chain fatty acids, and digestive enzyme activities. Metagenome sequencing and untargeted metabolomics were used to investigate the microbiota composition, functional profiles, and differential metabolites of the
cecal contents. We found that castration significantly decreased ADG, DMI, and G/F in cattle (P < 0.05). The serum testosterone, thyroxine, growth hormone (P < 0.05), and triiodothyronine (P < 0.01) concentrations significantly decreased in the steer group when compared to those of the bull group. The activities of cellulase, xylanase, pectinase, and β-glucosidase (P < 0.05) significantly decreased in the steer group, whereas the activities of lipase and α-amylase significantly increased. Moreover, castration significantly decreased the relative abundance of Ruminococcaceae_bacterium, Treponema_porcinum, Oscillibacter_sp. (P < 0.05), and Alistipes_senegalensis (P < 0.01), whereas the relative abundance of Phocaeicola_plebeius (P < 0.05) was significantly increased. Also, the relative abundance of Phocaeicola_plebeius was negatively correlated with testosterone levels, and the function of the cecal microbiota was enriched in the GH29 and GH97 families in the steer group. Metabolomic analysis indicated that castration increased the levels of L-valine, L-phenylalanine, L-aspartic acid, L-isoleucine, L-lysine, methionine, L-glutamic acid, and L-leucine, while decreasing the levels of α-ketoglutaric acid through the 2-oxocarboxylic acid metabolism pathway. In addition, α-ketoglutaric acid was negatively correlated with Oscillibacter_sp. (P < 0.01). Overall, castration can inhibit cattle growth by altering the composition of the
cecal microbiota. Therefore, this study provides a theoretical and practical basis for improving the growth performance of steers.
The castration of male cattle is a routine management practice in the United States. It improves the quality grade and tenderness of beef, and steers have a more desirable meat quality than intact males. Thus, it is conducted to meet the human demand for quality meat. However, castration reduces the body and carcass weights of steers, resulting in increased feeding costs. Therefore, it is important to study the mechanisms of weight loss in steers to provide a theoretical basis for improving their growth in the future. Our results found that castration reduced the testosterone and growth hormone concentrations in serum, changed the cecal microbial composition and function, and decreased the relative abundance of Ruminococcaceae_bacterium and Oscillibacter_sp especially. These changes in the cecal microbiota decreased the activities of digestive enzymes that degrade cellulose and hemicellulose and decreased the levels of the metabolite α-ketoglutaric acid, thus, inhibiting steer growth. Therefore, the
cecal microbiota may affect the growth performance of steers and provide a theoretical and practical basis for improving their growth.