日粮添加碳酸氢钠对湖羊生长性能、瘤胃发酵参数和细菌菌群的影响

Effects of sodium bicarbonate supplementation in diet on growth performance, rumen fermentation parameters and microbiota of Hu sheep

为了研究高精料全混合日粮中添加碳酸氢钠对湖羊生长性能、瘤胃发酵参数和细菌菌群的影响,选取体重相近、体况良好的3月龄湖羊16头,随机分为2组,每组8头,对照组饲喂基础日粮,试验组在基础日粮中添加0.5%的碳酸氢钠。预饲期5 d,正试期30 d。结果:与对照组相比,试验组湖羊的平均日增重显著升高(P<0.05),总增重和平均日采食量有升高的趋势(P<0.10),饲料转化率有降低的趋势(P<0.10);瘤胃pH值显著升高(P<0.05),总挥发性脂肪酸浓度显著降低(P<0.05),乙酸浓度有降低的趋势(P<0.10)。瘤胃细菌16S rRNA基因测序结果显示,与对照组相比,试验组α多样性未显著改变(P>0.05)。PCoA分析未将2个组的细菌菌群区分开。在属水平上,仅未分类的韦荣氏菌属的相对丰度在试验组中显著降低(P<0.05)。本研究结果表明,在全混合颗粒日粮中添加0.5%的碳酸氢钠在一定程度上提高了湖羊生长性能,改善了瘤胃环境,但对瘤胃细菌菌群结构影响较小。

This study was conducted to investigate the effects of sodium bicarbonate supplementation in diet on growth performance, rumen fermentation parameters and bacterial community of Hu sheep fed with a pelleted total mixed ration(TMR). Sixteen three-month-old Hu sheep(average body weight:(29±2.87 kg)) were randomly allocated into a control group(CON, n=8) and a treatment group(SB, n=8). The control group was fed with basal diet, and the treatment group was fed with a diet supplemented with 0.5% sodium bicarbonate. The experiment lasted for 35 days, including 5 days of adaptation period. The results showed that the average daily gain was significantly higher in the SB group than in the CON group(P<0.05). The total weight gain and average daily feed intake tended to increase in the SB group(P<0.10), and the feed conversion ratio tended to decrease(P<0.10), too. The ruminal pH was higher in the SB group(P<0.05), while the concentration of total volatile fatty acids was lower(P<0.05). The concentration of acetic acid tended to decrease(P<0.10). The 16 S rRNA gene sequencing of the rumen bacteria showed that sodium bicarbonate supplementation did not affect the α diversity(P>0.05) in the animals. PCoA analysis did not distinguish the two groups. At the genus level, only unclassified veillonellaceae was significantly lower in the relative abundance in the SB group than that in the CON group(P<0.05). In conclusion, adding 0.5% sodium bicarbonate to the total mixed pellet diet improved the growth performance and rumen environment of Hu sheep to a certain extent, but had little effect on the rumen bacterial populations in them.