本实验旨在评估丁酸钠(SB)添加对牛奶产量的影响,瘤胃发酵,营养消化,奶牛乳腺的发育和代谢调控。40头荷斯坦奶牛,平均体重710±18.5公斤,牛奶中72.8±3.66d(DIM),将41.4±1.42kg/d的牛奶产量分为DIM和牛奶产量阻断的四个处理。治疗组为对照组,低SB,中等SB,和高SB,每头母牛添加0、100、200和300g/d的SB,分别。这项研究持续了105天。生产牛奶,乳蛋白和乳糖呈二次升高(P<0.05),而脂肪校正牛奶,能量校正的牛奶和乳脂产量随SB添加量的增加呈线性增加(P<0.05)。膳食干物质的消化率,有机物,粗蛋白呈线性增加(P<0.05),而乙醚提取物的消化率,中性洗涤剂纤维,酸性洗涤剂纤维呈二次增加(P<0.05)。瘤胃pH呈二次下降(P=0.04),而总挥发性脂肪酸(VFA)随着SB添加量的增加而增加(P=0.03)。由于未改变的乙酸摩尔百分比和丙酸摩尔百分比的线性降低,乙酸与丙酸的比率线性增加(P=0.03)。羧甲基纤维素酶和α-淀粉酶的瘤胃酶活性,总细菌种群,总厌氧真菌,总原生动物,白乳球菌,R.黄酮,Butyrivibriofibrisolvens,琥珀酸纤维杆菌,嗜淀粉反刍动物呈线性增加(P<0.05)。血糖,尿素氮,非酯化脂肪酸线性下降(P<0.05),而总蛋白浓度呈线性增加(P=0.04)。此外,添加SB200g/d促进PPARγmRNA和蛋白表达(P<0.05),SREBF1,ACACA,FASN,SCD,CCNA2,CCND1,PCNA,Bcl-2、GPR41以及p-Akt/Akt和p-mTOR/mTOR的比值,BaxmRNA和蛋白表达降低(P<0.05),caspase-3和caspase-9。结果表明,通过刺激瘤胃发酵,添加SB可以增加产奶量和乳脂合成。营养消化,与乳脂合成和乳腺发育有关的基因和蛋白质表达。
This experiment was to evaluate the influence of sodium butyrate (SB) addition on milk production, ruminal fermentation, nutrient digestion, and the development and metabolism regulation of the mammary gland in dairy cows. Forty Holstein dairy cows averaging 710 ± 18.5 kg body weight, 72.8 ± 3.66 d in milk (DIM), and 41.4 ± 1.42 kg/d milk production were divided into four treatments blocked by DIM and milk production. Treatments were control group, low SB, medium SB, and high SB with 0, 100, 200 and 300 g/d of SB addition per cow, respectively. The study lasted for 105 d. Production of milk, milk protein and lactose quadratically increased (P < 0.05), while fat-corrected milk, energy-corrected milk and milk fat yields linearly increased (P < 0.05) with increasing SB addition. The digestibility of dietary dry matter, organic matter, and crude protein linearly increased (P < 0.05), whereas the digestibility of ether extract, neutral detergent fibre, and acid detergent fibre quadratically increased (P < 0.05). Ruminal pH quadratically decreased (P = 0.04), while total volatile fatty acids (VFA) quadratically increased (P = 0.03) with increasing SB addition. The acetic acid to propionic acid ratio increased (P = 0.03) linearly due to the unaltered acetic acid molar percentage and a linear decrease in propionic acid molar percentage. Ruminal enzymatic activity of carboxymethyl-cellulase and α-amylase, populations of total bacteria, total anaerobic fungi, total protozoa, Ruminococcus albus, R. flavefaciens, Butyrivibrio fibrisolvens, Fibrobacter succinogenes, and Ruminobacter amylophilus linearly increased (P < 0.05). Blood glucose, urea nitrogen, and non-esterified fatty acids linearly decreased (P < 0.05), while total protein concentration linearly increased (P = 0.04). Moreover, the addition of SB at 200 g/d promoted (P < 0.05) mRNA and protein expression of PPARγ, SREBF1, ACACA, FASN, SCD, CCNA2, CCND1, PCNA, Bcl-2, GPR41, and the ratios of p-Akt/Akt and p-mTOR/mTOR, but decreased (P < 0.05) mRNA and protein expressions of Bax, caspase-3, and caspase-9. The results suggest that milk production and milk fat synthesis increased with SB addition by stimulating rumen fermentation, nutrient digestion, gene and protein expressions concerned with milk fat synthesis and mammary gland development.