Effect of Methionine Hydroxy Analog on Hu Sheep Digestibility, Rumen Fermentation, and Rumen Microbial Community In Vitro

Abstract

This experiment was conducted to evaluate the effects of a methionine hydroxy analog (MHA) on in vitro gas production, rumen fermentation parameters, and rumen microbiota. Two different MHA, 2-hydroxy-4-(methylthio) butanoic acid isopropyl ester (HMBi) and the calcium salt of the hydroxy analog of methionine (MHA-Ca), were selected for in vitro experiments. The treatments were the Control group (0% of MHA), HMBi group (2%HMBi), and MHA-Ca group (2%MHA-Ca). Dry matter digestibility was measured after 12 h and 24 h of fermentation, and fermentation parameters and microbial composition were analyzed after 24 h. HMBi and MHA-Ca showed increased (p = 0.001) cumulative gas production in 3 h. The total volatile fatty acids, microbial protein (MCP) concentration, acetate, and acetate to propionate ratio in the HMBi and MHA-Ca groups were significantly higher than those in the Control group (p = 0.006, p = 0.002, p = 0.001, p = 0.004), and the NH3-N concentrations in the HMBi and MHA-Ca groups were significantly lower than those in the Control group (p = 0.004). The 16S rRNA sequencing revealed that the HMBi group had a higher (p = 0.039, p = 0.001, p = 0.027) relative abundance of Bacteroidetes, Firmicutes, and Synergistetes and a lower relative abundance of Proteobacteria (p = 0.001) than the Control group. At the genus level, Prevotella abundance was higher (p = 0.001), while Ruminobacter abundance was lower (p = 0.001), in the HMBi and MHA-Ca groups than in the Control group. Spearman’s correlation analysis showed that the relative abundance of Prevotella_1, Streptococcus, and Desulfovibrio was positively correlated with dry matter digestibility, MCP, and fermentation parameters. MHA, thus, significantly increased gas production and altered the rumen fermentation parameters and microbiota composition of sheep.

Effects of yeast culture and oxalic acid supplementation on in vitro nutrient disappearance, rumen fermentation, and bacterial community composition

“…Specifically, Prevotella, Selenomonas, and RFN20 were among the genera that were greatly increased with YC and OA supplementation and showed significant medium positive correlations with IVDMD in diet 1. Similarly, a report showed that Prevotella was positively correlated with digestibility (66). Another study also reported a positive correlation between Selenomonas and DM digestibility (67).…”

Lycium barbarum (Wolfberry) Branches and Leaves Enhance the Growth Performance and Improve the Rumen Microbiota in Hu Sheep

“…They play a crucial role in the metabolism of rumen substances. The rumen of Hu sheep was found to be dominated by the Firmicutes and Bacteroidota phyla, which accounted for over 80% of the relative abundance [ 57 ]. In this experiment, it has been shown that the main phyla present in all samples were Firmicutes , Bacteroides , Spirochaetota , Fibrobacterota , and Patescibacteria .…”

Rumen microbiota succession throughout the perinatal period and its association with postpartum production traits in dairy cows: A review

“…Similarly, a recent study on lactating yaks revealed that rumen Proteobacteria and Prevotella _1 abundance increased following supplementation with rumen-protected methionine (50.0 g/day), and Prevotella _1 had a positive association with DMI and rumen NH 3 –N concentration ( Zhao et al., 2021 ). An in vitro study showed that supplementation with 20 mg of calcium salt of the hydroxy analog of methionine increased Prevotella_1 , Streptococcus, and Desulfovibrio abundance in the rumen, and those rumen microorganisms had a positive association with dry matter digestibility and microbial protein concentration ( Li et al., 2023 ). These findings indicate that methionine and its analogs can affect rumen microbial communities, fermentation parameters, and production phenotypes.…”