Abstract
OBJECTIVE: An experiment was conducted to assess the effect of dragon fruit peel pellet (DFPP) as a rumen enhancer of dry matter consumption, nutrient digestibilities, ruminal ecology, microbial protein synthesis and rumimal methane production in Holstein crossbred bulls. METHODS: Four animals, with an average live-weight of 200±20 kg were randomly assigned in a 4×4 Latin square design to investigate the influence of DFPP supplementation. There were four different dietary treatments: without DFPP, and with 200, 300, and 400 g/h/d, respectively. RESULTS: Results revealed that dry matter consumption of total intake, rice straw and concentrate were not significantly different among treatments (p>0.05). It was also found that ruminal pH was not different among treatments (p>0.05), whilst protozoal group was reduced when DFPP increased (p<0.01). Blood urea nitrogen and NH3-N concentrations were increased at 400 g of DFPP supplementation (p<0.01). Additionally, volatile fatty acid production of propionate was significantly enhanced by the DFPP supplementation (p<0.05), while production of methane was consequently decreased (p<0.05). Furthermore, microbial protein synthesis and urinary purine derivatives were remarkably increased especially at 400 g of DFPP supplementation (p<0.05). CONCLUSION: Plant secondary compounds or phytonutrients (PTN) containing saponins (SP) and condensed tannins (CT) have been reported to influence rumen fermentation. DFPP contains both CT and SP as a PTN. The addition of 400 g of DFPP resulted in improved rumen fermentation end-products especially propionate (C3) and microbial protein synthesis. Therefore, DFPP is a promising rumen enhancer and indicated a significant potential of DFPP as feedstuff for ruminant feed to mitigate rumen methane production.