Effects of isobutyrate supplementation on ruminal microflora, rumen enzyme activities and methane emissions in Simmental steers.
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.
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
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C
Wang
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
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Liu
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
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YL
Zhang
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
C X
CX
Pei
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
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Zhang
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
Y X
YX
Wang
College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.|Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB, Canada.
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WZ
Yang
Shanxi Province Ecology and Livestock Industry Management Station, Taiyuan, Shanxi, China.
Y S
YS
Bai
Shanxi Province Ecology and Livestock Industry Management Station, Taiyuan, Shanxi, China.
Z G
ZG
Shi
Shanxi Province Ecology and Livestock Industry Management Station, Taiyuan, Shanxi, China.
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XN
Liu
D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D058610:Isobutyrates / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008697:Methane / Q000378:metabolism*; D012417:Rumen / Q000201:enzymology / Q000382:microbiology*
D058610:Isobutyrates; D008697:Methane
Simmental steers; isobutyrate; methane emissions; microflora; rumen enzyme activities