摘要
采用体外培养技术,研究了添加2mmol/L或4mmol/L支链氨基酸(branched-chain amino acid,BCAA)或支链脂肪酸(branched-chain volatile fatty acid,BCVFA)对玉米秸秆72h体外发酵的影响。结果表明,添加2mmol/L BCVFA或BCAA对总挥发性脂肪酸(TVFA)、乙酸、丙酸、丁酸、干物质(DM)和中性洗涤纤维(NDF)降解率均无显著影响。与BCVFA相比,添加相应BCAA均有升高TVFA的趋势。添加缬氨酸(Val)和异丁酸使异丁酸浓度较对照组增加2.85倍和3.12倍(P<0.05);添加亮氨酸(Leu)、异戊酸、异亮氨酸(Ile)和2-甲基丁酸后,异戊酸浓度增加2.20~2.50倍(P<0.05)。与相应BCVFA相比,Val、Leu和Ile使戊酸浓度分别增加27.69%(P<0.05),25.68%(P<0.05)和39.34%(P<0.05)。添加4mmol/L BCAA或BCVFA均导致发酵末期pH值下降,玉米秸秆的DM和NDF降解率显著增加,TVFA、乙酸、丙酸和丁酸有增加的趋势。添加异戊酸、Ile和2-甲基丁酸后丙酸水平增加29.94%(P<0.05),26.31%(P<0.05)和25.00%(P<0.05)。添加Val和异丁酸后异丁酸增加5.30倍和5.45倍(P<0.05)。添加Leu、异戊酸、Ile或2-甲基丁酸使异戊酸水平增加3.76~4.20倍(P<0.05)。与相应BCVFA相比,Val、Leu和Ile使戊酸浓度分别增加22.92%(P<0.05),33.33%(P<0.05)和55.00%(P<0.05)。PCR-DGGE结果显示,添加4mmol/L的BCAA或BCVFA明显改变瘤胃细菌多样性指数。以玉米秸秆为发酵底物时,BCAA或BCVFA的添加水平以4mmol/L较好,其中Val优于异丁酸,而Leu和异戊酸之间以及Ile和2-甲基丁酸之间无显著差异。
In vitro culture technique was adopted to study the effects of branched-chain amino acid (BCAA) or branched-chain volatile fatty acid (BCVFA) on fermentation of corn straw. Results showed that the concentration of total volatile fatty acid, acetic acid, propanoic acid, and butyric acid, and the degra- dation of dry matter (DM) and neutral detergent fiber (NDF) were not affected by 2 mmol/L BCAA or BCVFA supplementation. Compared with the BCVFA,BCAA supplementation tended to increase the con- centrations of total volatile fatty acid (TVFA). Supplementation of valine (Val) and isobutyric acid in- creased the concentrations of isobutyric acid in the ruminal fluid by 2.85 and 3.12 fold ( P 〈0.05). Addi tion of leucine (Leu),isovaleric acid,isoleucine (Ile) and 2-methylbutyric acid increased the concentration of isovaleric acid in the ruminal fluid by 2.20-2.50 fold ( P 〈0.05). Compared with the BCVFA,supple- mentation of Val,I.eu and Ile increased the concentration of valeric acid in ruminal fluid by 27.69~/oo ( P0.05) ,25.68~//oo ( P %0.05) and 39.34% ( P %0.05) respectively. Final pH decreased and degradation of DM and NDF of corn straw increased and the concentrations of TVFA,acetic acid, propanoic acid and bu- tyric acid tended to increase by 4 mmol/L BCAA or BCVFA supplementation. Addition of isovaleric acid, Ile and 2-methylbutyric acid increased the concentrations of propanoic acid by 29. 94% ( P %0. 05),26.31%0 ( P %0.05) and 25. creased the concentrations of tion of 4 mmol/L Leu,isoval acid in the ruminal fluid by 3 00% ( P 〈0.05) isobutyric acid in respectively. Supplementation of Val and isobutyric acid in- the ruminal fluid by 5.30 and 5.45 fold ( P 〈0.05). Addi- eric acid,Ile and 2-methylbutyric acid increased the concentration of isovaleric acid in the ruminal fluid by 3.76-4.20 fold ( P〈0.05). Compared with the BCVFA,supplementation of4 mmol/L Val,Leu and Ile increased the concentration of valeric acid in ruminal fluid by 22.92% ( P 〈 0.05) ,33.33% ( P 〈0.05) and 55.00% ( P 〈0.05) respectively. The results of PCR-DGGE revealed that the ruminal bacterial diversity index was obviously changed by BCAA or BCVFA addition at the concentra- tion of 4 mmol/L. These results implied that when corn straw was used as fermentation substrate,4 mmol/L was considered better suppliment for BCAA or BCFA. The effects of Val is better than that of isobutyric acid. There is insignificant difference between Leu and isovaleric acid,and Ile and 2-methylbutyrie acid.
出处
《新疆农业大学学报》
CAS
2012年第4期265-269,共5页
Journal of Xinjiang Agricultural University
基金
新疆农业大学校前期资助课题(XJAU200903)
关键词
支链氨基酸
支链脂肪酸
体外
发酵
PCR-DGGE
branched-chain amino acid
branched-chain volatile fatty acid
in vitro
fermentation
PCR-DGGE