Effect of Mulberry leaf pellet (MUP) supplementation on rumen fermentation and nutrient digestibility in beef cattle fed on rice straw-based diets

This study was designed to determine the effect of mulberry leaf pellets (MUP) on feed intake, digestibility and rumen fermentation in beef cattle. Four ruminal fistulated crossbred (Brahman × Thai native) beef cattle (420 ± 15 kg) were randomly assigned according to a 4 × 4 Latin square design. The dietary treatments were as follows; T1 = 0 g MUP/day; T2 = 200 g MUP/day; T3 = 400 g MUP/day; and T4 = 600 g MUP/day. All animals were kept in individual pen and concentrate was offered at 5 g/kg of body weight (BW) daily. The experiment was conducted for four periods, and each period lasted for 21 days. During the first 14 days, all animals were fed with respective diets and rice straw was fed ad libitum. During the last 7 days, the animals were moved to metabolism crates for total urine and fecal collection. The results of this finding revealed that rice straw and total dry matter intakes were increased (P<0.05) when MUP was supplemented and the highest was with supplementation at 600 g MUP/day. Apparent digestibilities of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (aNDF) and acid detergent fiber (ADF) were improved when increased level of MUP supplementation, especially at 600 g MUP/day (P<0.05). Moreover, supplementation of MUP has shown higher nitrogen balance than in control. Ruminal pH and temperature were not affected by MUP supplementation (P>0.05). In contrast, there was an increase of ammonia nitrogen (NH3-N) concentration as well as blood urea nitrogen (BUN) in the supplemented group. Moreover, total volatile fatty acid (TVFA), acetate (C2), butyrate (C4) concentration and acetate to propionate (C2:C3) ratio were linearly increased when increasing level of MUP supplementation (P<0.05) while no change in propionate (C3) concentration was found. Based on this result, it could be concluded that MUP can be used as a good protein source to improve rumen fermentation, nutrient digestibility and ruminants' productivity. It is recommended to supplement MUP at 600 g/day for cattle fed on low-quality roughages such as rice straw.