The effects of pantothenic acid (PA) and folic acid (FA) addition on digestibility coefficient, ruminal fermentation and urinary purine derivative (PD) excretion in dairy bulls were evaluated. Eight rumen-cannulated Holstein dairy bulls were allocated to a replicated 4 × 4 Latin square design according to a 2 × 2 factorial arrangement. Diets were supplemented with two levels of FA (0 or 8.0 mg/kg dietary dry matter [DM]) and two of PA (0 or 60 mg/kg DM). The PA × FA interaction was not significant for all variables. Both supplements increased DM intake and average daily gain, but decreased a feed conversion ratio. Digestibility of DM, organic matter, crude protein and neutral detergent fibre increased, but ether extract digestibility was unchanged for both supplements. Digestibility of acid detergent fibre only increased with FA supplementation. For both supplements, ruminal pH and ammonia nitrogen (N) decreased, but total volatile fatty acid (VFA) concentration increased. Acetate proportion only increased with FA supplementation. Propionate proportion decreased for both supplements. Consequently, the acetate to propionate ratio increased. For both supplements, activity of xylanase and pectinase, population of Ruminococcus albus, R. flavefaciens, Fibrobacter succinogenes and Ruminobacter amylophilus and total PD excretion increased. Additionally, activity of carboxymethylcellulase, cellobiase, α-amylase and protease, and population of total bacteria, fungi, protozoa, methanogens, Butyrivibrio fibrisolvens and Prevotella ruminicola increased with FA addition. The results suggested that PA and FA supplementation stimulated ruminal microbial growth and enzyme activity, resulting in an increased digestibility coefficient and ruminal total VFA concentration in dairy bulls.

中文翻译：

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泛酸和叶酸补充剂对奶牛全消化道消化系数、瘤胃发酵、微生物酶活性、微生物区系和尿嘌呤衍生物的影响

评估了泛酸 (PA) 和叶酸 (FA) 添加对奶牛消化系数、瘤胃发酵和尿嘌呤衍生物 (PD) 排泄的影响。根据 2 × 2 因子排列，将八头瘤胃插管荷斯坦奶牛分配到重复的 4 × 4 拉丁方设计中。日粮中添加了两种水平的 FA（0 或 8.0 mg/kg 日粮干物质 [DM]）和两种水平的 PA（0 或 60 mg/kg DM）。PA × FA 交互作用对所有变量均不显着。两种补充剂都增加了干物质摄入量和平均日增重，但降低了饲料转化率。干物质、有机物、粗蛋白和中性洗涤纤维的消化率增加，但两种补充剂的乙醚提取物消化率没有变化。酸性洗涤纤维的消化率仅随着 FA 的补充而增加。对于两种补充剂，瘤胃 pH 值和氨氮 (N) 降低，但总挥发性脂肪酸 (VFA) 浓度增加。醋酸盐比例仅随着 FA 补充剂的增加而增加。两种补充剂的丙酸盐比例均有所下降。因此，醋酸盐与丙酸盐的比例增加。对于两种补充剂，木聚糖酶和果胶酶的活性，白色瘤胃球菌,R. flavefaciens,琥珀酸纤维杆菌和嗜淀粉瘤胃杆菌和总 PD 排泄增加。此外，羧甲基纤维素酶、纤维二糖酶的活性，α-淀粉酶和蛋白酶，以及总细菌、真菌、原生动物、产甲烷菌的种群，丁酸弧菌和普氏菌随着 FA 的增加而增加。结果表明，添加 PA 和 FA 可刺激瘤胃微生物生长和酶活性，从而提高奶牛的消化率和瘤胃总 VFA 浓度。