混菌固态发酵麸皮条件优化及离体消化研究

Study on the Optimized Conditions and Digestion in vitro of Wheat Bran with Solid-state Fermentation by Multi-strains

试验选用不同比例组合的枯草芽孢杆菌、酵母菌及乳酸菌(Lactobacillus B和Lactobacillus W),经固态发酵筛选发酵麸皮的最优条件,并通过提取草鱼肠道不同部位的消化酶液对最优发酵麸皮进行离体消化研究。以未发酵麸皮作为对照组,依据接种菌种及其比例设6个试验组,每组3个重复进行固态发酵,测定发酵麸皮的酸度、菌落数及粗蛋白质含量,筛选出最优发酵组;利用草鱼肠道提取消化酶液,对未发酵麸皮和最优发酵麸皮进行离体消化,测定干物质、粗蛋白质的消化率及氨基酸的含量。结果表明,试验3组发酵麸皮的粗蛋白质含量最高,为23.67%,与未发酵组相比提高了56.56%;且菌落数在96h达到7.8×108 CFU/g,明显高于其他试验组,而酸度呈先下降后上升的变化趋势,故筛选出试验3组为最优发酵组。未发酵麸皮组和最优发酵麸皮组的粗蛋白质、干物质消化率及氨基酸含量均以前肠最高,中肠次之,后肠最低,且最优发酵麸皮组体外消化率均显著高于未发酵麸皮组(P<0.05)。经营养成分分析和离体消化研究发现,发酵麸皮具有较高的营养价值和消化率,可部分替代蛋白饲料。

In this study, the best solid-state fermentation condition of wheat bran was optioned by using different ratio of Lactobacillus B, Lactobacillus W, Bacillus subtilis and Saccharomycetes, the digestion of fermentation wheat bran was analyzed by extraction of intestinal digestive enzyme from the grass carp. Experiment was arranged six groups according to the different microbial combination, the unfermented wheat bran acted as control group, and each treatment was repeated 3 times. The best condition was selected through measuring the acidity, bacteria colony and crude protein content of fermentation bran. The digestion of unfermented wheat bran and best fermentation wheat bran was carried out by using the digestive enzyme from the grass crap in vitro, the dry matter and crude protein digestibility and amino acid content were determined. The results showed that the crude protein content of group 3 was the highest, the content was improved by 56.56% compared with the control group. Moreover, the bacteria colonies were reached 7.8 × 10^8 CFU/g in 96 h in group 3, which was apparently higher than those in other groups, and the acidity was firstly increased and then decreased. All these exhibited the group 3 were the best one. In addition, the former intestine showed the highest dry matter and crude protein digestibility and amino acid content between unfermented wheat bran group and fermentation wheat bran group, followed by middle intestine, and posterior intestine was minimum, moreover, the digestibility of best fermentation wheat bran was significantly greater than that of unfermented wheat bran in vitro （P〈0. 05）. The results indicated that the fermentation wheat bran have the higher nutritional value and digestibility, which can partially replace the protein feed.