Gunun et al., The J. Anim. Plant Sci. 27(6):2017 1758 IMPROVING THE QUALITY OF SUGARCANE BAGASSE BY UREA AND CALCIUM HYDROXIDE ON GAS PRODUCTION, DEGRADABILITY AND RUMEN FERMENTATION CHARACTERISTICS N. Gunun 1* , P. Gunun 2 , M. Wanapat 3 , A. Cherdthong 3 , S. Kang 4 and S. Polyorach 5 1 Program in Animal Production Technology, Faculty of Technology, Udon Thani Rajabhat University, Udon Thani, 41000, Thailand; 2 Department of Animal Science, Faculty of Natural Resources, Rajamangala University of Technology-Isan, SakonNakhon Campus, Phangkhon, Sakon Nakhon, 47160, Thailand; 3 Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand; 4 National Institute of Education, Phnom Penh, Cambodia; 5 Department of Animal Production Technology and Fisheries, Faculty of Agricultural Technology, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520, Thailand Corresponding author: Email: nirawan_kku@hotmail.com ABSTRACT The objective of this study was to determine the influence of urea and whole soybean meal or calcium hydroxide [Ca(OH)2] treatment on sugarcane bagasse nutritive values and in vitro fermentation. The experimental design was a completely randomized design (CRD) and the dietary treatments were sugarcane bagasse treated with urea ( 0, 20, 40g/kg) and whole soybean meal or Ca(OH)2 ( 0, 25, 50g/kg) . It was found that the protein content of sugarcane bagasse was significantly increased by whole soybean meal and urea treatment, and the values ranged from 65-71 g/kg DM. On the other hand, treatment of Ca(OH)2 50 g/kg with urea 40 g/kg could reduce (p<0.05) fiber content of sugarcane bagasse and the values were 533, 514 and 104 g/kg DM for NDF, ADF and ADL, respectively. Gas production from the insoluble fraction (b), potential extent of gas production (a+b) and cumulative gas production were significantly increased (p<0.05) in sugarcane bagasse treated with urea 40 g/kg and urea 40 g/kg + whole soybean meal 25 g/kg (55.3, 53.5 and 50.1 ml), respectively. Urea and Ca(OH)2 treatment could increase DM and OM degradability, true digestibility and microbial mass of sugarcane bagasse(p<0.05). Furthermore, the concentration of C3, C2 and C2:C3 were improved by urea and whole soybean meal or Ca(OH)2 treatment. In addition, methane production was decreased in sugarcane bagasse treated with urea 40 g/kg in the present study. Based on this experiment, it could be concluded that treatment of urea and Ca(OH)2 was an alternative method to improve the nutritive value of sugarcane bagasse, gas production, digestibility and ruminal fermentation characteristics. Keywords: Sugarcane bagasse, Urea, Calcium hydroxide, Digestibility, Rumen fermentation. INTRODUCTION In the tropics, majority of roughage source for ruminant consist of leftovers from plant harvest, grasses and foliage growing on roadsides or waste land. However, it is critical during dry season and hectic season of cultivation ( Wanapat, 1986; Wanapat and Devendra, 1992) when it is a limitation of availability of feed. Alternative feed resources and industrial by-product are potential to use as roughage source for livestock production. Sugarcane bagasse is sugarcane industrial by- product practically used by farmers for ruminant feeding especially during the long dry season ( Costa et al., 2015; Pessoa et al., 2009; Leme et al., 2003) . However, sugarcane bagasse is low in nutritive value as very low level of protein (<30 g/kg), high fibre and lignin content (NDF >800 g/kg, ADF > 600 g/kg and ADL>100 g/kg) ( Balgess et al., 2007; Okano et al., 2006), and low digestibility (200-300 g/kg); thus, resulted in poor animal performance (Jayasuiry, 2007). Therefore, a potential use of sugarcane bagasse as a ruminant feed may be realized through the development of physical, chemical and biological treatments to disrupt the lingo-cellulose complex. Various methods have been used to improve the nutritive value of sugarcane bagasse including physical, chemical, biological treatments for ruminants feeding ( Balgees et al., 2007; Okano et al., 2006) . Ahme et al. (2013) revealed that nutritive values of sugarcane bagasse were improved by urea treatment. In addition, Balgees et al. (2015) reported that 50 g/kg urea and 30 g/kg ammonia treatments of sugarcane bagasse increased the CP content and in vitro dry matter digestibility. However, due to the cost of urea was remarkably expensive, it resulted in a higher cost of production. Fadel Elseed et al. ( 2003) suggested that calcium hydroxide [Ca(OH)2] could improve rumen digestibility. The concentrated The Journal of Animal & Plant Sciences, 27(6): 2017, Page: 1758-1765 ISSN: 1018-7081