日粮中不同水平单宁对绵羊瘤胃发酵的影响

Effects of Different Levels of Dietary Tannin on Ruminal Fermentation in Sheep

旨在探讨日粮中来源于柠条的缩合单宁对绵羊瘤胃发酵参数的影响。选择体重为40 kg左右的健康杜蒙绵羊羯羊15只,按体重相近的原则随机分为3组:对照组(n=5),饲粮中不含单宁;试验Ⅰ组(n=5)和试验Ⅱ组(n=5),饲粮中分别含2%和4%单宁。分别于试验期晨饲前(0 h)和晨饲后3、6、9 h采集各组绵羊瘤胃液,测定和比较各组绵羊瘤胃内环境指标,包括pH值、氨氮(NH3-N)浓度、菌体蛋白(BCP)浓度。结果表明,饲喂含有2%(试验Ⅰ组)和4%(试验Ⅱ组)单宁的日粮对杜蒙绵羊的瘤胃pH值无显著影响(P>0.05);饲喂含有2%(试验Ⅰ组)和4%(试验Ⅱ组)单宁的日粮3 h和6 h后,绵羊瘤胃NH3-N浓度显著(P<0.05)降低;饲喂含有2%(试验Ⅰ组)和4%(试验Ⅱ组)单宁的日粮6 h和9 h后,绵羊瘤胃BCP浓度显著(P<0.05)提高。日粮中添加2%和4%来源于柠条的单宁,对绵羊瘤胃pH值无影响,可降低瘤胃NH3-N浓度,提高瘤胃BCP浓度。

The purpose of this study was to investigate the effects of condensed tannin derived from Caragana korshinskii in diets on ruminal fermentation parameters in sheep.A total of 15 healthy Dorper and Mongolian crossbred wether weighing around 40 kg were selected and randomly divided into 3 groups according to their body weight.The control group(n=5)contained no tannins in the diet;the test groupⅠ(n=5)andⅡ(n=5)received the diet containing 2%and 4% of tannin,respectively.The ruminal fluid of each group was collected before morning feeding(0 h)and 3 h,6 h and 9 h after morning feeding,respectively,and the rumen internal environment indicators of the experimental wether,including pH value,ammonia nitrogen(NH3-N)concentration and bacterial protein(BCP)level,were measured and statistically compared.The results showed that feeding the diets containing 2%(test groupⅠ)and 4%(test groupⅡ)of tannin had no significant(P>0.05)effect on ruminal pH value;the wether had significantly(P<0.05)lower ruminal NH3-N concentration 3 h and 6 h after receiving the diets containing 2%(test groupⅠ)or 4%(test groupⅡ)of tannin;the ruminal BCP level of the wether was significantly(P<0.05)elevated 6 h and 9 h after receiving the diets containing 2%(test groupⅠ)or 4%(test groupⅡ)of tannin.The combined data suggested that while dietary supplementation of 2% or 4% of tannin derived from Caragana korshinskii had no impact on ruminal pH value in wether,it was able to reduce the ruminal NH3-N concentration and ruminal BCP level.