Effects of Phytonutrients on Ruminal Fermentation, Digestibility, and Microorganisms in Swamp Buffaloes

SIMPLE SUMMARY: Fermentation in ruminants can influence greenhouse gas production, especially methane (CH(4)) production. Phytonutrients (PTN) and secondary metabolites (tannins, saponins) have antimicrobial activity which can be used for the inhibition of rumen methanogens and the reduction of methane emissions in ruminants. The aim of the present study was to investigate the influence of PTN containing both mangosteen peel powder and banana flower powder on feed consumption, nutrient digestibility, and rumen microorganisms in swamp buffaloes. The results suggest that supplementation of PTN can improve fiber digestibility, increase the proteolytic and cellulolytic bacteria, and alter rumen volatile fatty acids (VFAs), especially increased C(3) and reduced methane production. This study shows that PTN containing either mangosteen peel powder (MSP) or banana flower powder (BFP) could be used as a rumen modifier. ABSTRACT: This experiment aimed to use dietary sources containing phytonutrients (PTN) such as mangosteen peel powder (MSP) and banana flower powder (BFP) as sources of phytonutrients. Four swamp buffalo bulls fitted with rumen fistulae were used as experimental animals. A digestion trial covering four periods was used according to a 4 × 4 Latin square design with four treatments: Treatment 1 (T1) = control (Cont), T2 = supplementation of PTN1 fed at 100 g/d, T3 = supplementation of PTN2 fed at 100 g/d, and T4 = supplementation of PTN3 fed at 100 g/d. The experiment was conducted for four periods; each period lasted for 21 days. All animals were fed a concentrate mixture at 0.5% body weight, while rice straw, water, and mineral blocks were fed ad libitum. The findings revealed significant increases in the digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF), while no changes in dry matter feed consumption occurred due to PTN supplementation. Rumen fermentation end-products, such as total volatile fatty acids (TVFA), propionic acid (C(3)), and butyric acid (C(4)), were notably enhanced (p < 0.05) and there were the highest in PTN2 and PTN3, whilst acetic acid (C(2)) was significantly decreased with PTN supplementation groups. Furthermore, the rumen protozoal population was suppressed (p < 0.05), which resulted in decreased rumen methane production (p < 0.05), while the bacterial population was enhanced. Using PTN sources can improve rumen fermentation as well as mitigating rumen methane production.