Zhang Jun, Yang Yuntian, Lei Xinjian, Wang Yannan, Li Yanhua, Yang Zhiqiang, Yao Junhu
College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China.
Fuping County Animal Husbandry Development Center, Fuping 711700, Shaanxi, China.
Anim Nutr. 2023 Feb 17;13:289-301. doi: 10.1016/j.aninu.2023.02.001. eCollection 2023 Jun.
This study evaluated the effects of active dry yeast (ADY) supplementation and supplementation strategies on ruminal fermentation, bacterial community, blood metabolites, and growth performance in young dairy goats. Sixty young female Guanzhong dairy goats of similar age (4.00 ± 0.50 months) and BW (19.65 ± 0.41 kg) were randomly divided into 3 groups ( = 20): (1) basal diet group (CON); (2) basal diet continuously supplemented with 3.0 g/goat per day commercial ADY (a proprietary strain of with 5.0 × 10 cfu/g) group (CSY); (3) basal diet with intermittently supplemented ADY group (ISY; 5 d supplementation with ADY at 4.5 g/goat per day following 5 d of no supplementation). The experiment lasted 67 d with the first 7 d as an adaptive period. Rumen fluid and blood samples were collected bi-weekly. Data were analyzed using the MIXED procedure combined with the SLICE option in SAS. Specific orthogonal contrasts of ADY vs. CON and CSY vs. ISY were also analyzed. During the experimental period, ADY supplementation resulted in greater DMI ( = 0.03), ruminal acetate proportion ( < 0.01) and acetylesterase activity ( = 0.01), and blood contents of glucose ( = 0.01) and IgM ( = 0.02) and tended to have greater ADG ( = 0.05) and paunch girth ( = 0.06) than the CON, despite the propionate proportion ( = 0.03) and contents of total protein ( = 0.04) and IgA ( = 0.03) being lower. The lower ruminal NH-N ( < 0.01) and blood urea nitrogen ( = 0.07) contents indicated greater nitrogen utilization with ADY supplementation. ADY supplementation showed persistent effects after it was stopped because the BW at 12 months of age ( = 0.03) and birth weight of lambs ( = 0.02) were greater than the CON. However, the ISY did not show those benefits and had significantly lower relative abundances of fiber-degrading related bacteria than the CSY. In conclusion, ADY supplementation, especially continuously supplemented, may enhance ADG and ADG:DMI ratio by improving DMI, ruminal cellulolytic bacteria abundance and enzyme activity, nitrogen utilization, and immune status. These findings provide a theoretical basis for the rational application of ADY and have important practical implications for the design of nutritional strategies in growing dairy goats.
本研究评估了添加活性干酵母（ADY）及其添加策略对幼年奶山羊瘤胃发酵、细菌群落、血液代谢物和生长性能的影响。选取60只年龄相近（4.00±0.50月龄）、体重相近（19.65±0.41 kg）的关中雌性幼年奶山羊，随机分为3组（每组20只）：（1）基础日粮组（CON）；（2）基础日粮中每天每只山羊持续添加3.0 g商业ADY（一种含有5.0×10 cfu/g的专利菌株）组（CSY）；（3）基础日粮中间歇性添加ADY组（ISY；每5天不添加，随后5天每天每只山羊添加4.5 g ADY）。试验持续67天，前7天为适应期。每两周采集瘤胃液和血液样本。数据采用SAS中的MIXED程序结合SLICE选项进行分析。还分析了ADY与CON以及CSY与ISY的特定正交对比。在试验期内，与CON组相比，添加ADY使干物质采食量（DMI）更高（P = 0.03）、瘤胃乙酸比例更高（P < 0.01）、乙酰酯酶活性更高（P = 0.01）、血糖（P = 0.01）和IgM血液含量更高（P = 0.02），并且平均日增重（ADG）（P = 0.05）和腹围（P = 0.06）有增加趋势，尽管丙酸比例（P = 0.03）、总蛋白含量（P = 0.04）和IgA（P = 0.03）较低。瘤胃NH₃ - N（P < 0.01）和血液尿素氮（P = 0.07）含量较低表明添加ADY提高了氮利用率。停止添加ADY后仍有持续影响，因为12月龄体重（P = 0.03）和羔羊出生体重（P = 0.02）均高于CON组。然而，ISY组未表现出这些益处，且与CSY组相比纤维降解相关细菌的相对丰度显著较低。总之，添加ADY，尤其是持续添加，可通过提高DMI、瘤胃纤维素分解菌丰度和酶活性、氮利用率以及免疫状态来提高ADG和ADG:DMI比值。这些发现为ADY的合理应用提供了理论依据，对生长奶山羊营养策略的设计具有重要的实际意义。
