微生物固态发酵对饲料营养特性的影响

采用酵母菌单菌和酵母菌、乳酸菌混菌对玉米、豆粕和麸皮组成的饲料进行好氧固态发酵,探索其对饲料营养成分和体外功能活性的影响。结果表明,发酵后,粗蛋白、总磷和低分子量肽含量显著(P<0.05)提高,而粗脂肪含量显著(P<0.05)降低。氨基酸方面,酵母单菌和混菌发酵后,天冬氨酸、丝氨酸、酪氨酸、苯丙氨酸和精氨酸的含量显著(P<0.05)提高。与发酵前相比,酵母单菌发酵还显著(P<0.05)提高了总氨基酸含量。饲料经过单菌和混菌发酵后,总酚含量、维生素B2、B6以及咖啡酸、没食子酸的含量亦显著(P<0.05)提高。体外功能评价试验表明,发酵饲料提取液对大肠埃希菌、金黄色葡萄球菌、藤黄微球菌和沙门氏菌等4种指示菌均有抑制效果,并对酵母菌和乳酸菌有促生长作用。由此可知,在本试验条件下,酵母单菌发酵和酵母、乳酸菌混菌发酵处理可有效提高饲料的营养品质。

Effects of microbial solid-state fermentation on nutritional value of feeds

To determine the effects of microbial solid-state fermentation on nutritional compositions and in vitro functional activity, the formula feed consisted of corn, soybean meal and wheat bran was fermented with single Saccharomyces cerevisiae strain or mixed stain of S. cerevisiae and Lactobacillus casei. It was shown that contents of crude protein, total phosphorus and low-molecular weight peptide were increased (P<0.05), whereas the crude fat content was decreased (P<0.05). Amino acid determination depicted an increase (P<0.05) in concentrations of aspartate, serine, tyramine, phenylalanine and arginine after the single or mixed fermentation. Moreover, the total amino acid concentration was higher (P<0.05) in S. cerevisiae-fermented feeds, compared with un-fermented feed. The contents of total phenol, VB2, VB6, caffeic acid and pyrogallic acid were also increased (P<0.05). Functional assessment in vitro showed that the water extracts of fermented feed had anti-microbial effect (P<0.05) on the growth of intestinal pathogens, including Escherichia coli, Staphylococcus aureus, Micrococcus luteus and Salmonella enterica. The extracts also had promoting effect (P<0.05) on the growth of S. cerevisiae and L. casei. In conclusion, the fermentation with S. cerevisiae alone or mixed with L. casei could improve the nutritional quality of feeds.