The Effect Of Shrub Tannin On Rumen Fermentation And Rumen Microflora, Immunity And Production Performance In Sheep

This study evaluated the feeding value of shrubs by recording the changes of nutrients and anti-nutrient substance based on in vitro culture. Simultaneously, the effect of vegetable tannins on the diet degradation in sheep's digestive tract was studied. This study also included vegetable tannins'effects on sheep's performance, rumen microorganism and the body immunity.This paper has 2 parts and covers 8 research points:Part I. Feeding value evaluation for major dominant shrubs in the desert steppe region.1. Nutrients seasonal changes of 12 major feeding shrubs in the desert steppe region.2. Anti-nutrient components analysis of 12 major feeding shrubs in the desert steppe region.3. The effects of 12 major feeding shrubs in the desert steppe region on sheep in vitro fermentation indexes.Part II. Vegetable tannins'effects on the rumen fermentation and other sheep physiological functions.1. Different levels of vegetable tannins'influence on the fermentation indexes of sheep in vitro.2. Different levels of vegetable tannins in the diets affect the cellulolytic bacteria in rumen of sheep.3. Different levels of vegetable tannins in the diets affect the methanogen in rumen of sheep.4. Different levels of vegetable tannins in the diets affect the body immune function of sheep.5. Different levels of vegetable tannins in the diets affect the nitrogen metabolism and performance of sheep.Results:In this study, the content of Crude Protein (CP), Organic Matter (OM) in 12 major feeding shrubs in the desert steppe region was decreasing with the prolonging of the growth period. Meanwhile, the average value of Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF) and Acid Detergent lignin (ADL) were also decreasing. The Dry Matter (DM) loss was ranging from 54.18% to 66.78%. The content of total polyphenol, tannins, simple phenols and Condensed Tannin (CT) had extremely significant differences (p<0.01) among different kinds of shrubs and different growth periods. The average CT content in 12 shrubs was a V curve, ranging from 25.66g/kg DM to 46.66g/kg DM as the grow period was extended. This proved that those shrubs can be used as future forage plants.Based on in vitro selection experiments, adding tannins to the diets will significant decreased the digestion ratio of the diets in vitro. This effect was limited in fermentation indexes of VFA and the dry matter loss. When the amount of tannins was 3.5%, MFAEI showed the highest value, which means best fermentation results.1. In vivo experiments: the diets with 1%, 2%, 3.5% tannins would lead to the changes of the microflora in the rumen of sheep. In this study, after feeding 2 hours, three types of cellulolytic bacteria ( Rum nococc albus, Fibrobacter succinogenes and Ruminococcus lavefaciens), were quantitatively analyzed by quantitative PCR. The results were: Cellulolytic bacteria had the highest copy number in per milliliter rumen fluid when feeding forage with 1% tannins. And the relative quantity sequence of cellulolytic bacteria was: 1% group﹥2% group﹥3% group. The number of cellulolytic bacteria decreased with the extending of feeding days. And the total number of methanogen in rumen is: 3.5% group﹥2% group﹥1% group. When feeding diets with same level of tannins, methanogen in rumen would decrease when feeding days increased. In addition, low level of tannins would help the microorganism flora in rumen to improve the diet digestion.2. Different levels of tannins had different effects on CD4+and CD8+ T- lymphocytes in serum of sheep bodies. Comparing with control groups, the content of CD4+and CD8+ T- lymphocytes increased, but not significantly.3. The research on different levels of tannins'effects on sheep performance showed that: when feeding with diets containing 2% tannins, sheep had the best performance. 22 days later after adding tannins, comparing with control group and 3.5% group, the 2% tannins group got significantly (P<0.05) higher daily weight gain and lower ratio of feed to gain(P<0.05). As for 1% tannins adding group, the daily weight gain was 44g/d more than the control group, and the ratio of feed to gain was 4.02 lower than the control one. But these differences are not significant. Similarly, 3.5% tannins adding group got 2g/d lower average daily weight gain and 1.82 higher ratio of feed to gain. These differences were also not significant. Lower level of tannins would increase the average daily weight gain and decrease the ratio of feed and gain. But when the amount of tannins in diets was≥3.5%, it would be harmful to sheep performance. In conclusion, under specific conditions of this study, when fed with diet containing 2% DM tannins, the sheep had good performance. Although shrubs had higher nutrient content and they are easier to be digested, their tannins range was between 2.57%DM～4.67% DM, which is higher than the optimum value. Therefore, when using shrubs as crude material of roughage, modulation is necessary to decrease the content of tannins in order to reduce the negative effects caused by tannins.