Effect of high roughage diet on enzyme profile and biochemical changes in the rumen of crossbred bullocks

Rumen fistulated crossbred bullocks (4) of6 2Y2 years old, were divided into 2 groups. The animals were fed 2 diets consisting of paddy straw and concentrate mixture in the ratio of70:30 (high roughage, HR) and 30:70 (low roughage, LR) in 2x2 switch over design to study fibre degrading enzyme profile and fermentation pattern in the rumen. Concentrate mixture was prepared for high roughage ration (HR) and low roughage ration (LR) in such a manner to make both the diets isonitrogenous and variable in crude fibre to have better information of ruminaI enzymes responsible for fibre degradation. Paddy straw and concentrate were mixed thoroughly by adding some W'3.ter before feeding. The DM and CP intake in the animals fed different diets did not differ. The crude fibre intake was significantly higher (l.12 kg/d) in the animals fed high roughage diet compared to the animals fed low roughage diet (0.56 kg/d). However, TDN intake was significantly lower (2.26 kg/d) in the animals fed high roughage diet compared to the animals fed low roughage diet (3.18 kg/d). Rumen liquor samples were collected at 0, 2, 4,6 and 8 h post feeding for the estimation of rumen biochemical parameters. The results revealed high pH value in high roughage group as compared to low roughage group due to low lactic acid concentration in the rumen liquor of animals fed high roughage diet. The concentration of total N, TCA PRT. N and Lactic acid was significantly lower in high roughage diet. No significant difference was observed 111 TYFA and ammonia nitrogen concentration between 2 groups. For the estimation of enzymes activities, samples of rumen content were collected from the rumen and after thorough mixing were fractioncd into different microbial compartments, viz. particll late material (PM), cellular fraction (C) and extracellular fraction (EC) by lysozyme treatment. The activity of a amylase, carboxymethyl cellulase, microcrystalline cellulase, a-glucosidase, B-glucosidase and xylanase in rumen content varied with high and Jow roughage diets. Activity of all the enzymes was higher in particulate material (PM) fraction compared to cellular fraction (C) and extracellular fraction (EC). The difference in the activity of various enzymes in 2 different groups may be due to change in microbial activity. The activity ofxylanase and f3-glucosidase was significantly higher (136.14 and 19.62 Ilmole/min/l OOg rumen content, respectively) in the rumen content of animals fed high fibre diet indicating more activity of fibre degrading microbes.