Effect of banana flower powder supplementation as a rumen buffer on rumen fermentation efficiency and nutrient digestibility in dairy steers fed a high-concentrate diet

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Four rumen-fistulated dairy steers, two and a half year old with liveweight of 220±15.0kg, were randomly assigned according to a 4×4 Latin square design to study the effect of banana flower powder (BAFLOP) supplementation as a rumen buffering agent on ruminal pH, nutrient digestibility and rumen fermentation fed a high-concentrate diet. The four dietary treatments were BAFLOP supplementation at 0, 10, 20 and 30g/kg of dry matter intake (DMI), respectively. During the experimental periods, all steers were fed a diet containing roughage to concentrate ratio of 30:70 at 20g DMI/kg of body weight and rice straw was used as a roughage source. Based on the present study, the results revealed that dry matter, organic matter and crude protein digestibilities were not affected (P>0.05) by BAFLOP supplementation, whereas digestibilities of neutral detergent fiber and acid detergent fiber increased with the increasing levels of BAFLOP supplementation (P<0.05). It was also found that total nitrogen (N) intakes were similar among treatments. However, fecal N excretions decreased with the increasing levels of BAFLOP supplementation, while urinary N excretions were similar among treatments. BAFLOP supplementation increased N balance both absorption and retention (P<0.05). Moreover, purine derivative absorption and microbial protein synthesis were increased by BAFLOP supplementation, whereas efficiency of microbial nitrogen supply (EMNS) and microbial nitrogen supply were similar among treatments. In addition, ruminal temperature, ammonia nitrogen, and blood urea nitrogen were not influenced by BAFLOP supplementation, whilst ruminal pH enhanced (P<0.05) in steers supplemented with BAFLOP at 20 and 30g/kg of DMI. The concentration of total volatile fatty acid and acetic acid increased with BAFLOP supplementation, whereas propionic and butyric acid remained the same. The present findings showed that BAFLOP supplementation enhanced total bacterial, protozoal, and cellulolytic bacterial growth, while numbers of fungal zoospores, amylolytic and proteolytic bacteria were similar among treatments. In conclusion, BAFLOP supplementation improved rumen ecology and nutrient digestibility by enhancing ruminal pH, nitrogen utilization, EMNS and ruminal microbial population. This study suggested that BAFLOP could be supplemented as a rumen buffering agent at 20–30g/kg of DMI.