The aim of the study was to evaluate the effect of crude protein (CP) levels in concentrate and Sesbania grandiflora pod meal (SG) supplementation on feed intake, rumen fermentation, and methane (CH4) mitigation in Thai purebred beef cattle. Four cattle with 100 ± 5.0 kg body weight were used in this study. A 2 × 2 factorial experiment in a 4 × 4 Latin square design was conducted, in which factor A was the CP levels in concentrate of 14% and 16% of dry matter (DM) and factor B was the supplement levels of SG at 0.4% and 0.6% DM intake, respectively. The results showed that the CP content in concentrate and SG supplementation had no interaction effect on intake, digestibility, ruminal ecologies, ruminal fermentation products, and nitrogen utilization. Increasing CP content to 16% significantly (p < 0.05) increased the ruminal ammonia nitrogen (NH3-N), nitrogen (N) intake, N absorption, and N retention. SG supplementation significantly (p < 0.05) decreased CP digestibility, NH3-N, blood urea nitrogen, and protozoa. In addition, SG significantly decreased acetate (C2), acetate to propionate ratio, methane, and fecal N excretion, while it significantly increased total volatile fatty acids (VFAs) and propionate (C3) concentration. In conclusion, SG could mitigate methane emission and enhance nitrogen utilization.

This research assessed the impact of cassava chips (CSC) and winged bean tubers (WBT) with various starch modification methods on the chemical composition, ruminal degradation, gas production, in vitro degradability, and ruminal fermentation of feed using an in situ and in vitro gas production technique. Experimental treatments were arranged for a 2 × 5 factorial, a completely randomized design with two sources of starch and five levels of modification treatments. Two sources of starch were CSC and WBT, while five modification treatments of starch were: no modification treatment, steam treatment, sodium hydroxide (NaOH) treatment, calcium hydroxide (CaOH2) treatment, and lactic acid (LA) treatment. The starch modification methods with NaOH and CaOH2 increased the ash content (p < 0.05), whereas the crude protein (CP) content was lower after treatment with NaOH (p < 0.05). Steam reduced the soluble fraction (a) and effective dry matter degradability of WBT in situ (p < 0.05). In addition, the WBT steaming methods result in a lower degradation rate constant in situ (p < 0.05). The degradation rate constants for the insoluble fraction (c) in the untreated CSC were higher than those of the other groups. Starch modification with LA reduced in vitro dry matter degradability at 12 and 24 h of incubation (p < 0.05). The starch modification method of the raw material showed the lowest pH value at 4 h (p < 0.05). The source of starch and starch modification methods did not influence the in vitro ammonia nitrogen concentrations, or in vitro volatile fatty acids. In conclusion, compared to the CSC group and untreated treatment, treating WBT with steam might be a more effective strategy for enhancing feed efficiency by decreasing or retarding ruminal starch degradability and maintaining ruminal pH.

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The aim of the study was to evaluate the effect of crude protein (CP) levels in concentrate and Sesbania grandiflora pod meal (SG) supplementations on feed intake, rumen fermentation, and methane (CH4) mitigation in Thai purebred beef cattle. Four cattle with 100 &plusmn; 5.0 kg body weight were used in this study. A 2 &times; 2 factorial experiment in a 4 &times; 4 Latin square design were conducted, in which factor A was the CP contents in concentrate of 14, and 16% of dry matter (DM) and factor B was the supplement contents of SG at 0.4% and 0.6% DM intake, respectively. The results showed that the CP contents in concentrate and SG had no interaction effect on intake, digestibility, ruminal ecologies, ruminal fermentation products, and nitrogen utilization. Increasing CP contents in concentrate did not influence DM intake and nutrients&rsquo; digestibility, and SG supplementation at 0.6% significantly (P&lt;0.05) decreased CP digestibility. Increasing CP content to 16% increased significantly (P&lt;0.05) the ruminal ammonia nitrogen (NH3-N) concentration while decreased significantly (P&lt;0.05) the NH3-N concentration, protozoal number, and blood urea nitrogen (BUN) at 4 h post-feeding. The 0.6% supplementation of the SG increased significantly average total volatile fatty acids (VFAs) and propionate (C3) concentration while decreased significantly average acetate (C2), C2:C3 ratio, and CH4 production, which was 2.71% for C2, 13.17% for C2:C3 ratio, and 4.37% for CH4 production lower than 0.4% supplementation. Fecal nitrogen excretion was significantly decreased when supplemented with 0.6% of the SG. In conclusion, 0.6% of the SG supplementation showed a greater effect on intake, rumen manipulation, and CH4 mitigation and would recommend supplementation to a concentrate-based diet containing either 14% or 16% CP content.