枯草芽孢杆菌发酵复配饲料产品质量评定

Quality evaluation of compound feed fermented by Bacillus subtilis

试验旨在研究枯草芽孢杆菌发酵复配饲料的产品质量。试验通过考察麦麸添加量、辅料比例(大蒜皮与银杏叶添加量)、发酵时间对蛋白酶活的影响,优化发酵条件,检测发酵前后活菌数与pH值、常规营养成分和小肽、可溶性蛋白、游离氨基酸的含量以及发酵过程中蛋白水解度,以全面评价发酵饲料的营养价值和品质。结果表明,以蛋白酶活为指标,通过单因素及正交试验,确定最优发酵条件为2%麦麸、2.5%大蒜皮+2.5%银杏叶、发酵时间72 h。在此条件下,蛋白酶活为342.36 U/g。枯草芽孢杆菌UL-191在基质上长势良好,活菌数可达3.5×10^(14) CFU/g。发酵前后水分和粗灰分含量无明显变化,粗蛋白和粗脂肪含量明显增长,大分子蛋白降解成小分子蛋白。蛋白水解度、小肽含量、游离氨基酸含量均随着发酵时间延长均呈上升趋势,其中发酵72 h时,蛋白水解度可达25%,小肽、游离氨基酸含量可达182.9、1006.4μg/g。研究表明,试验制备的发酵复配饲料产品质量较高,具有一定市场应用前景。

The experiment aimed to study the product quality of the Bacillussubtilis-fermented compound feed.The trial optimized the fermentation conditions by examining the effects of wheat bran addition,the ratio of auxiliary materials(addition of garlic peel and ginkgo leaf),and fermentation time on protease activity,and comprehensively evaluated the nutritional value and quality of the fermented feed by detecting the number of live bacteria and pH value before and after fermentation,as well as the content of conventional nutrients,peptides,soluble protein,and free amino acids,and the degree of protein hydrolysis during the fermentation process.The results showed that based on protease activity as an indicator,the optimal fermentation conditions were determined through single-factor and orthogonal tests to be 2%wheat bran,2.5%garlic peel+2.5%ginkgo leaf,and a fermentation time of 72 hours.Under these conditions,the protease activity was 342.36 U/g.Bacillussubtilis UL-191 grew well on the substrate,with the number of live bacteria reaching 3.5×10^(14) CFU/g.There were no significant changes in moisture and crude ash content before and after fermentation,while the content of crude protein and crude fat increased significantly,with large molecular proteins being degraded into proteins of smaller molecular weights.The degree of protein hydrolysis,peptide content,and free amino acid content all showed an upward trend with the extension of fermentation time.At 72 hours of fermentation,the degree of protein hydrolysis reached 25%,and the contents of peptides and free amino acids reached 182.9 and 1006.4μg/g,respectively.The study indicates that the quality of the experimentally prepared fermented compound feed is high and has certain market application prospects.