Effects Of Diet Concentrate:Roughage Ratio On Digestibility, Ruminal Digestion And Metabolism In Sheep

Six jinzhong sheep (BW27.9±2.7kg,1-year old) were used in a3×3Latin square, to evaluate the effects of diets with different ratios of concentrate to roughage on the environment in ruminal and digestibility. The diet was composed of mixed concentrate and corn straw, concentrate:roughage ratio was3:7,5:5and7:3respectively. The results showed that:The ratios of concentrate to roughage also had no significant effect on apparent digestibility of dry matter, organic matter and crude fiber (P>0.05). Apparent digestibility of crude protein in7:3group was significantly lower than the other two groups (P<0.01). Apparent digestibility of ether extract in3:7group was significantly higher than the other two groups (P <0.05). Apparent digestibility of neutral detergent fiber and acid detergent fiber in the7:3group was significantly lower than the3:7group (P<0.01), with the5:5group where had no difference (P>0.05).The intake Nitrogen, digestible nitrogen and retention nitrogen of5:5group were significantly higher than3:7group (P<0.01),3:7group was significantly higher than the7:3group (P<0.01). Fecal nitrogen in3:7group was significantly lower than the other two groups (P<0.05). The urinary nitrogen and nitrogen utilization in three groups was not significant (P>0.05). The concentrations of Purine derivative and allantoin were not effected by concentrate to forage ratio (P>0.05). The concentrations of uric acid in7:3group was significantly higher than3:7groups (P<0.01).The ruminal pH all three groups showed a lower after rising trend, then reached the minimum at3h after feeding, were significantly lower than0h (P<0.05), and then gradually increased. Average pH of the three groups were6.67,6.46and6.38, the3:7group was significantly higher than the other two groups (P <0.05), with the proportion of concentrate increased pH gradually decline. The total VFA, acetic, propionate valerate concentration, and ratio of acetate to propionate had no significant difference (P>0.05) among the three groups, the butyrate concentration in3:7group was significantly lower than5:5and7:3group (P<0.01), the isobutyric concentration in7:3group was significantly lower than3:7and5:5group (P<0.01), whereas the concentration of isovaleric was was significantly higher in5:5group than the other two group (P<0.05). The NH3-N concentrations were elevated after feeding, at3h reached the maximum, then decreased gradually;7:3group was significantly lower than the other two groups (P<0.05). The average MCP concentrations were0.95,0.93,1.08mg/ml, the differences among the three groups was not apparent (P>0.05). Amount of protozoa were3.91,3.74,8.38×105/ml, the three groups was not significant (P>0.05). protease activity were3.54,5.61,4.17μg/(min×ml) respectively, three had no significant differences (P>0.05). The urease activity were12.42,12.91,13.72nmol/(min X ml) respectively, three groups were not significant (P>0.05). The endo-xylnaase, pectinase, p-glueosidaes, amylase, endo-gluenaase, FPase activity in ruminal liquid was not effected by ratios of concentrate to roughage (P>0.05).These results demonstrated, dietary forage to concentrate ratio had a significant effect on the digestion and ruminal digestion and metabolism in sheep.