College of Animal Sciences and Veterinary Medicines, Shanxi Agricultural University, Taigu, Shanxi, China.
Agriculture and Agri-Food Canada Research Centre, Lethbridge, AB, Canada.
J Anim Physiol Anim Nutr (Berl). 2015 Feb;99(1):123-131. doi: 10.1111/jpn.12191. Epub 2014 Apr 7.
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.
本研究旨在评估异丁酸补充对饲喂玉米秸秆日粮的西门塔尔牛瘤胃微生物区系、酶活性和甲烷排放的影响。8 头瘤胃可插管的西门塔尔牛采用重复 4×4 拉丁方试验设计。处理组为对照组（无异丁酸）、低异丁酸（LIB）、中异丁酸（MIB）和高异丁酸（HIB），每天每头牛分别添加 8.4、16.8 和 25.2 g 异丁酸。异丁酸通过手工混合到精料中。日粮由 60%玉米秸秆和 40%精料（干物质基础）组成。干物质采食量（平均 9 kg/d）限制在自由采食量的 90%以内。总细菌、纤维素分解菌和厌氧真菌的数量呈线性增加，而原生动物和总产甲烷菌的数量则呈线性减少。随着异丁酸补充量的增加，瘤胃白弯菌、黄化瘤胃球菌、纤维丁酸弧菌和纤维黏细菌的数量呈线性增加。实时 PCR 定量分析发现，随着异丁酸补充量的增加，白色瘤胃球菌、黄色瘤胃球菌、纤维丁酸弧菌和纤维黏细菌的数量呈线性增加。羧甲基纤维素酶、木聚糖酶和β-葡萄糖苷酶的活性呈线性增加，而蛋白酶的活性呈线性降低。随着异丁酸补充量的增加，甲烷产量呈线性降低。随着异丁酸补充量的增加，玉米秸秆的纤维素和半纤维素的有效降解率呈线性增加，而日粮中粗蛋白的有效降解率呈线性降低。本研究结果表明，异丁酸的添加改善了牛的瘤胃微生物区系、酶活性和甲烷排放。这表明异丁酸以剂量依赖的方式刺激消化微生物或酶。在本试验的实验条件下，异丁酸的最佳添加量约为每天每头牛 16.8 g。
