Effects of Tannin on Rumen Fermentation Parameters and Microflora Structure of Preweaning Calves
This study was conducted to study the effects of starter supplemented with tannin on rumen fermen-tation parameters and microflora structure of preweaning calves.Sixty healthy 1-day-old Chinese Holstein fe-male calves with similar birth weight[(39.9±1.9)kg]were randomly divided into 4 groups with 15 calves per group,and each calf was raised in a single pen.Calves in control group(CON group)were fed starter,and those in experimental groups were fed the starter supplemented with 0.30％(QTE1 group),0.45％(QTE2 group)and 0.60％(QTE3 group)quebracho tannin-chestnut tannin extracts(QTE,total tannin con-tent ≥73％).The QTE was composed of quebracho tannin extract(condensed tannin)and chestnut tannin ex-tract(hydrolyzed tannin),and the ratio of them was 2:1.The experiment lasted for 63 days.All calves were weaned uniformly during the experiment and rumen fluid was collected on the last day of the experiment.The results showed that:1)the final body weight of calves in experimental groups was significantly higher than that in CON group(P＜0.05).2)Although rumen fluid pH,the concentrations of microbial protein and total vola-tile fatty acid,the molar ratios of acetic acid and valeric acid,and acetic acid/propionic acid ratio were not sig-nificantly affected by QTE supplemental level in starter(P＞0.05),the concentration of ammonia-nitrogen showed a quadratic decreasing trend(P=0.05),the molar proportion of propionic acid tended to increase line-arly(P=0.10),the molar proportion of butyric acid showed a significant quadratic increasing(P=0.03),and the molar proportions of isobutyric acid and isovaleric acid showed a trend to decrease linearly(P=0.08 and P=0.05)with the increase of QTE supplemental level.The ammonia nitrogen concentration in QTE2 group was the lowest,and the molar proportion of propionic acid in QTE2 group was the highest.The molar proportion of butyric acid in QTE2 group was significantly higher than that in CON group and QTE3 group(P＜0.05);the molar proportion of isovaleric acid in QTE2 group was significantly lower than that in CON group and QTE3 group(P＜0.05).3)The Shannon index in QTE1 group,QTE2 group and QTE3 group was significantly higher than that in CON group(P＜0.05),and the highest value was found in the QTE2 group.4)At the phylum level,the relative abundance of Actinobacteria increased linearly with the increase of QTE supplemental level(P=0.01),and the QTE2 group and QTE3 group were significantly higher than CON group and QTE1 group(P＜0.05);the ratio of the relative abundance of Firmicutes/Bacteroidetes decreased linearly with the increase of QTE supplemental level(P=0.01),and the QTE1 group,QTE2 group and QTE3 group were significantly lower than CON group(P＜0.05).At the genus level,the relative abundance of Prevotella increased linearly with the increase of QTE supplemental level(P=0.01),and the QTE2 group and QTE3 group were significantly higher than CON group(P＜0.05);the relative abundance of Butyrivibrio tended to decrease linearly with the increase of QTE supplemental level(P=0.01);the relative abundance of Olsenella tended to increase linearly(P=0.05).In conclusion,tannin improves the rumen fermentation pattern and growth of preweaning calves by increasing the diversity of rumen microflora and relative abundances of beneficial bacteria of calves,optimizing the structure of rumen microflora.The optimal supplemental level of QTE in the starter of preweaning calves under the condition of this study is 0.45％.[Chinese Journal of Ani-mal Nutrition,2024,36(4):2497-2511]
万方数据
维普
