Rehman et al., J. Anim. Plant Sci. 24(Suppl. 1):2014 Proceedings of “International Livestock Nutrition Conference” held on October, 23-24, 2013 at UVAS, Lahore 36 CHEMICAL COMPOSITION AND DIGESTION KINETICS OF UREA-MOLASSES TREATED WHEAT STRAW ENSILED WITH FIBROLYTIC ENZYME IN RUMINALLY CANNULATED BUFFALO BULLS A. U. Rehman 1, M. U. Nisa 2 ; A. Shazad 2 ; M. Sarwar 2 ; O. A Khan 2 and M. Sharif 2 1 Department of Animal Science, University College of Agriculture, University of Sargodha 2 Institute of Animal Nutrition and Feed Technology, University of Agriculture Faisalabad, Faisalabad, Punjab, Pakistan Corresponding author email: linknisa@gmail.com ABSTRACT Experiment was conducted to evaluate the effect of increasing fibrolytic enzyme level on nutrient composition and digestion kinetics of urea treated wheat straw (WS). Wheat straw was treated with 4% urea and 6% molasses and was ensiled with 0 (E0), 1 (E1), 2 (E2) and 3 (E3) g of enzyme /Kg of dry matter (DM). Enzyme mixture was dissolved in water and sprayed on WS. Then after an hour of enzyme treatment, molasses and urea were dissolved in water and sprayed on enzyme-treated WS. Wheat straw was ensiled in 36 laboratory silos under Completely Randomized Design for twenty one days. Application of enzymes on ensiled WS did not affect (P>0.05) DM, crude protein, true protein, neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents. Enzyme treatment did not affect (P>0.05) the pH of the ensiled WS. Digestion kinetics of DM, NDF and ADF also remained unaltered (P>0.05) across all the treatments. On the basis of results it is concluded that enzyme did not affect the nutrient profile of WS because of alkaline pH due to rapid production of ammonia in the silo. Key words: fibrolytic enzyme, digestion kinetics, wheat straw INTRODUCTION Wheat straw is abundantly available by-product. However, its low protein, high fiber contents and low digestibility limit its use in ruminant nutrition (Abo-Eid et al., 2007). Nutritive value of WS can be improved by adding different chemicals and feed additives. Fibrolytic enzymes as feed additive at the time of forge ensilation results in conversion of fiber contents of the forage into fermentable sugars by using microbes to produce lactic acid (McDonald et al., 1991). Fibrolytic enzymes used in animal feeds are the products of batch fermentation of bacterial and fungal origin (Pendleton, 2000 and Cowan, 1994). Ensilation of urea-treated WS with fiber degrading enzymes may result in improved ammonia fixation and reduced fiber contents of the ensiled WS. Keeping in view, the study was planned to examine the nutrient composition and digestion kinetics of urea-treated WS ensiled with varying level of fibrolytic enzymes. MATERIALS AND METHODS Wheat straw was ground through a Wiley mill (2 mm screen) for chemical analyses. Commercial cellulase+hemicellulase mixture of enzymes (Allzyme®, an Aspergillus nigar product by Alltech) was used as an inoculant to ensiled WS. Wheat straw was treated with 4% urea and 6% molasses and was ensiled with 0 (E0), 1 (E1), 2 (E2) and 3 (E3) g of enzyme /Kg of dry matter (DM). Enzyme mixture was dissolved in water for spraying on WS. Then molasses and urea was dissolved in water and sprayed on enzyme-treated WS. Amount of water used was sufficient to attain 50% moisture in WS. The treated WS was ensiled in 36 (3 for each enzyme level) laboratory silos. These silos were pressed and sealed to achieve the anaerobic conditions for 21 days at room temperature. After 21 days the sample from each silo were collected and analyzed to determine pH and OM, DM, TP, CP, NDF and ADF contents. For digestion kinetics, four ruminally cannulated buffalo bulls (400+20 Kg) were used in 4×4 Latin square design to evaluate the fibrolytic enzyme treated ensiled WS. Nylon bags measuring 10×23 cm with an average pore size of 50 μm were used and incubated in the rumen for 0, 1, 2, 4, 6, 10, 16, 24, 36, 48 and 96 h, in reverse order and removed all at the same time (Sarwar et al., 2004). The bags were washed and dried in a forced air oven at 55°C. The lag time was calculated according to method described by Mertens and Loften (1980) by using formula. Lag time = ln (100) – Intercept / Rate of digestion. The dry matter, OM, CP NDF and ADF were determined by AOAC 1990 .The collected data was subjected to analysis of variance technique using multivariate analysis in General Linear Model option of SPSS 17.0 (SPSS Inc., Chicago, IL, USA). In case of significance (P<0.05) Duncan’s New Multiple Range Test was applied to separate the means. The Journal of Animal & Plant Sciences, 24(Suppl. 1): 2014, Page: 36-39 ISSN: 1018-7081