Effects Of Biacin,Cobalt And 5,6-Dimethylbenzimidazole Complexes On The Digestion And Metabolism,Rumen Fermentation Parameters And Blood Biochemical Indexes In Sheep Under The Condition Of High Concentrate

The purpose of this experiment was to study the effects of adding niacin,cobalt and5,6-dimethylbenzimidazole（5,6-DMB）complexes on the digestion and metabolism,rumen fermentation parameters and blood biochemical indexes of sheep under the condition of high concentrate.Twenty healthy Kazakh rams with similar body weight（46.12±2.46kg）were selected and randomly divided into 2 groups,10 in each group.The control group was fed the basal diet,and the experimental group was additionally supplemented with 130 mg/d niacin,100 mg/d5,6-dimethylbenzimidazole and 0.5 mg/kg cobalt in the basal diet.The experimental period was 26 d,the first 14 d was the pre-trial period,and the last 12 d was the positive trial period.During the experiment,the animals were fed ad libitum,and the changes in feed intake and body weight were recorded.Digestive metabolism test was performed 8 days before the positive trial period,and feces and urine samples were collected daily and recorded by weighing.Rumen fluid and blood samples were collected at 0（recorded as 0 h before feeding）,1,3,5,and 7 h after the positive trial period 4 days after feeding.the result shows:（1）Under the condition of the diet with the ratio of concentrate to crude 7:3,compared with the control group,the daily weight gain of the experimental group increased significantly（P<0.01）,and the dry matter,crude protein,crude fat,cellulose,phosphorus of the experimental group The apparent digestibility of total energy and total energy increased significantly（P<0.05）;compared with the control group,the retention of nitrogen,phosphorus and energy in the experimental group increased significantly（P<0.05）,and the retention rates of nitrogen and phosphorus increased significantly High（P<0.05）.（2）Compared with the control group,the p H value of rumen fluid in the experimental group was significantly increased at 3 hours after feeding（P<0.05）,and the average concentration of rumen microprotein was significantly increased（P<0.05）.The concentration of volatile fatty acids increased but did not change significantly（P>0.05）;3 h after feeding,the concentration of propionic acid in the experimental group increased significantly（P<0.05）,and the concentration of acetic acid decreased（P>0.05）.（3）Compared with the control group,the concentrations of L-lactic acid and D-lactic acid in the rumen of the experimental group were significantly decreased at 3 h after feeding（P<0.05）,and the contents of L-lactic acid and D-lactic acid in serum were significantly lower at 1 h after feeding.h began to decrease significantly（P<0.05）;the activity of lactate dehydrogenase in the rumen of the experimental group decreased significantly at 3 h（P<0.05）,and the activity of succinate dehydrogenase increased（P>0.05）;3 h after feeding,the NAD⁺activity in the experimental group decreased significantly（P<0.05）,and the NADH activity showed a decreasing trend（P>0.05）.（4）The content of vitamin B₁₂ in the rumen fluid,blood and urine of the experimental group was higher than that of the control group（P>0.05）,serum enzyme activity and serum nitrogen content had no significant changes（P>0.05）,glucose and triglyceride were not significantly changed（P>0.05）.The content increased but had no significant change（P>0.05）.（5）At the phylum classification level,the phyla with relative abundance of TOP10 were screened together.Compared with the control group,the relative abundance of Proteobacteria and Synergistetes in the experimental group increased（P>0.05）,the relative abundance of Bacteroidetes decreased（P>0.05）.At the taxonomic level of the genus,the relative abundance of Quinella,Succinivbrionaceae,Fretibacterium and Prevotellaceae compared with the control group The relative abundance of Succiniclasticum and Veillionellaceae decreased（P>0.05）.In conclusion,the addition of niacin,cobalt and 5,6-DMB complex under the condition of high concentrate can increase the feed intake and apparent digestibility of each nutrient in sheep,improve rumen fermentation,and regulate the metabolism of propionic acid.The application of niacin and vitamin B12 in ruminant nutrition provides theoretical basis.