Influence of Supplementing Sesbania grandiflora Pod Meal at Two Dietary Crude Protein Levels on Feed Intake, Fermentation Characteristics, and Methane Mitigation in Thai Purebred Beef Cattle.

Narirat Unnawong,Anusorn Cherdthong,Sarong So

doi:10.3390/vetsci8020035

Abstract

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.

Highlights

The emission of methane (CH4) is labeled as a greenhouse gas, which is one of the hot environmental problems [1]
The chemical composition of S. grandiflora pod meal (SG) was analyzed according to Association of Official Agricultural Chemists (AOAC) [15] including dry matter (DM, ID 967.03), organic matter (OM, ID 942.05), crude protein (CP) (ID 984.13), ether extract (EE, ID 920.39), and acid detergent fiber (ADF), and Van Soest et al.’s [16] method for neutral detergent fiber (NDF)
The concentrate was formulated to contain 14.10 and 16.06% DM intake to test the effect of SG containing saponin and tannins on nitrogen utilization efficiency

Summary

Introduction

The emission of methane (CH4) is labeled as a greenhouse gas, which is one of the hot environmental problems [1]. Mitigating CH4 emission benefits the environment, and enhances the energy utilization in ruminants. Various approaches including dietary manipulation, antibiotics, and plant secondary compounds (PSCs) for CH4 mitigation have been tested, and using PSCs such as saponins and tannins has been shown to be the most effective approach recently [3,4,5] for CH4 mitigation. Saponins affect CH4 mitigation by lowering the protozoa population and changing volatile fatty acid (VFA) production patterns, as well as enhancing fiber degradation [6]. The S. grandiflora pods contain 35% of crude protein (CP) and PSCs including tannins, flavonoids, steroids, and triterpenes [10,11]. The effect of S. grandiflora pod meal (SG) containing saponins and tannins with different dietary CP levels has not yet been evaluated. Increasing protein content in concentrate might be prevented from ruminal microbial degradation when SG containing tannins increase

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