Enhancing Rumen Fermentation and Bacteria Community in Sika Deer () through Varying Levels of Dragon Fruit Peel Polyphenolic Extract: An In Vitro Study.

The aim of this study is to investigate the effect of dragon fruit peel polyphenolic extract (DFPE) on gas production, rumen fermentation, and bacterial communities in sika deer using an in vitro technique. Three treatments with different DFPE levels (DFPE0, base diet; DFPE5, base diet + 5 mg/g DFPE; DFPE10, base diet + 10 mg/g DFPE, respectively; n = 6) were implemented. The phenolic composition of DFPE, gas production (GP), ammonia nitrogen (NH-N), volatile fatty acid (VFA), and bacteria communities was evaluated after 24 h of incubation. The results showed that GP and NH-N were reduced by DFPE supplementation. Total VFA, isovaleric acid, and valeric acid were increased ( < 0.05) by the addition of DFPE. No changes ( > 0.05) were observed in pH, acetic acid, propionic acid, isobutyric acid, butyric acid, and the ratio of acetic acid to propionic acid. Additionally, the alpha indexes, including Sobs, Shannon, and Ace, were increased by DFPE supplementation. Moreover, at the phylum level, DFPE supplementation increased ( = 0.01) but reduced ( < 0.01) . At the genus level, compared to DFPE0, the DFPE10 had increased relative abundances of ( < 0.01), ( = 0.01), ( < 0.01), ( < 0.01), and ( < 0.01), decreased relative abundances of ( < 0.01), ( = 0.01), and ( < 0.01). Compared to DFPE0, DFPE5 had no change ( > 0.05) in all bacteria at the genus level except for decreased relative abundance of ( < 0.01). These results indicated that DFPE may be able to be used as a feed additive to enhance fermentation parameters and improve ruminal bacteria communities in Sika deer.