INFLUENCE OF CRUDE PROTEIN AND ENERGY LEVEL ON FEED INTAKE, RUMINAL AMMONIA NITROGEN, AND METHYLGLYOXAL PRODUCTION IN SWAMP BUFFALOES (BUBALUS BUBALIS)

The present experiments were conducted to investigate the effect of protein (CP) and energy levels in concentrate supplementation on feed intake, ruminal ammonia nitrogen (NH3-N) and methylglyoxal (MG) production in swamp buffaloes (Bubalus bubalis) fed rice straw based diet. Eight Thai - rumen fistulated male swamp buffaloes, about 4 years old with body weight (BW) of 381 +/- 10 kg, were randomly assigned to four dietary treatments in two consecutive 4 x 4 Latin square design experiments. Four buffaloes in first square received four different concentrate supplementations containing different CP levels at 92, 124, 181 and 219 g/kg while other four in the second square received different concentrate containing different total digestible nutrient (TDN) levels at 740, 761, 806 and 843 g/kg, respectively. All buffaloes were fed concentrate mixtures at 10 g/kg BW and rice straw was offered ad libitum. Under this investigation, the result revealed that total dry matter feed intake (DMI) increased with the increasing levels of CP (P<0.05) while increasing TDN up to 843 g/kg in concentrate mixture reduced DMI (P<0.05). Moreover, increasing CP and TDN levels in concentrate mixture reduced ruminal pH of buffaloes. However, ruminal temperature was not affected by either CP or TDN levels in concentrate mixture (P>0.05). In addition, ruminal NH3-N concentration and blood urea nitrogen of buffaloes increased with the increasing levels of CP in the concentrate (P<0.05) while there was no effect of TND level in concentrate on NH3-N and BUN of buffaloes in the second square (P>0.05). In addition, rumen MG productions were different among treatments by either CP or TDN levels in concentrate mixture, especially at 6 and 8 hour post morning feeding (P<0.05). The highest ruminal concentration of MG production was found in buffaloes received concentrate mixture containing CP and TDN levels at 124, 181 g/kg CP and 761, 806 g/kg TDN, respectively. The mean values of MG production concentration influenced by CP and TDN levels in concentrate mixtures were in the range of 24.5-28.1 and 3.8-4.5 mg/dl, respectively. Based on the present study, increasing CP and TDN levels in concentrate diet increased feed intake while ruminal pH was reduced. NH3-N and BUN concentration were increased by CP levels. Levels of CP and TDN between 124-181 g/kg CP and 761-806 g/kg TDN, respectively, in the concentrate mixture showed the highest ruminal MG concentration in swamp buffaloes fed on rice straw.