Effects of isobutyrate supplementation on ruminal microflora, rumen enzyme activities and methane emissions in Simmental steers

Abstract

The objective of this study was to evaluate the effects of isobutyrate supplementation on rumen microflora, enzyme activities and methane emissions in Simmental steers consuming a corn stover-based diet. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. The treatments were control (without isobutyrate), low isobutyrate (LIB), moderate isobutyrate (MIB) and high isobutyrate (HIB) with 8.4, 16.8 and 25.2 g isobutyrate per steer per day respectively. Isobutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate [dry matter (DM) basis]. Dry matter intake (averaged 9 kg/day) was restricted to a maximum of 90% of ad libitum intake. Population of total bacteria, cellulolytic bacteria and anaerobic fungi were linearly increased, whereas that of protozoa and total methanogens was linearly reduced with increasing isobutyrate supplementation. Real-time PCR quantification of population of Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens and Fibrobacter succinogenes was linearly increased with increasing isobutyrate supplementation. Activities of carboxymethyl cellulase, xylanase and β-glucosidase were linearly increased, whereas that of protease was linearly reduced. Methane production was linearly decreased with increasing isobutyrate supplementation. Effective degradabilities of cellulose and hemicellulose of corn stover were linearly increased, whereas that of crude protein in diet was linearly decreased with increasing isobutyrate supplementation. The present results indicate that isobutyrate supplemented improved microflora, rumen enzyme activities and methane emissions in steers. It was suggested that the isobutyrate stimulated the digestive micro-organisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum isobutyrate dose was approximately 16.8 g isobutyrate per steer per day.

Invited review: Large-scale indirect measurements for enteric methane emissions in dairy cattle: A review of proxies and their potential for use in management and breeding decisions

“…Other compounds known for their antimicrobial activities were also shown to induce reductions in both MeP and methanogen numbers (Kubo et al, 1993;Iwamoto et al, 2002). Examples of these are nitrates (van Zijderveld et al, 2010;Veneman et al, 2015), anacardic acid contained in cashew nut shell liquid (Shinkai et al, 2012), monensin (Shinkai et al, 2012), and isobutyrate (Wang et al, 2015). The relationship between rumen methanogen abundance and methanogenesis is less clear when changes in enteric CH 4 emissions are modulated by diet or are a consequence of selecting phenotypes related to feed efficiency or MeY.…”

Effects of dietary protein levels and 2‐methylbutyrate on ruminal fermentation, nutrient degradability, bacterial populations and urinary purine derivatives in Simmental steers

“…Similarly, dietary BCVFA supplementation provided essential nutrient for ruminal cellulolytic bacteria and promoted microbial growth (Cummins & Papas, ; Flachowsky et al., ). Previous studies found that populations of R. albus , R. flavefaciens , B. fibrisolvens and F. succinogenes, and activities of carboxymethyl‐cellulase and xylanase increased, but microbial protease activity decreased with isovalerate or isobutyrate supplementation (Liu et al., ; Wang et al., ). The microbial α‐amylase activity increased with isovalerate supplementation (Liu et al., ), but was unaffected by isobutyrate supplementation (Wang et al., ).…”

“…Previous studies found that populations of R. albus , R. flavefaciens , B. fibrisolvens and F. succinogenes, and activities of carboxymethyl‐cellulase and xylanase increased, but microbial protease activity decreased with isovalerate or isobutyrate supplementation (Liu et al., ; Wang et al., ). The microbial α‐amylase activity increased with isovalerate supplementation (Liu et al., ), but was unaffected by isobutyrate supplementation (Wang et al., ). However, Moharrery () reported that ruminal protease and α‐amylase activities were not affected by a mixed isoacids (isobutyrate, isovalerate and valerate) supplementation.…”

Evaluación de diferentes niveles de inclusión de plantas nativas de sabanas inundables sobre una dieta basal de Brachiaria humidicola y su efecto sobre la producción de metano in vitro

“…Este efecto pudo estar determinado por los elevados niveles de amonio resultante de la degradación de la proteína, el cual es utilizado como fuente de nitrógeno por las poblaciones ruminales y por lo tanto es un factor determinante en la síntesis de células microbiales (Bryant y Robinson, 1962), las cuales favorecen una mayor degradación de los componentes fibrosos de la dieta (Van Soest, 1982). La síntesis de células microbiales también se pudo beneficiar por los incrementos en los niveles de isobutirato, un ácido graso de cadena ramificada que surge a partir de la fermentación de los aminoácidos de cadena ramificada y que es requerido para el crecimiento de la mayoría de los microorganismos ruminales y una adecuada degradación de los componentes estructurales de la dieta (Wang et al, 2015). Varias investigaciones reportan el efecto benéfico del isobutirato en la degradación de la materia seca (Cummins y Papas, 1985), FDN (Yang, 2002) y hasta en reducir las emisiones de metano en novillas (Wang et al, 2015).…”

“…La síntesis de células microbiales también se pudo beneficiar por los incrementos en los niveles de isobutirato, un ácido graso de cadena ramificada que surge a partir de la fermentación de los aminoácidos de cadena ramificada y que es requerido para el crecimiento de la mayoría de los microorganismos ruminales y una adecuada degradación de los componentes estructurales de la dieta (Wang et al, 2015). Varias investigaciones reportan el efecto benéfico del isobutirato en la degradación de la materia seca (Cummins y Papas, 1985), FDN (Yang, 2002) y hasta en reducir las emisiones de metano en novillas (Wang et al, 2015).…”