乳酸菌及丙酸钙对全株玉米和燕麦青贮饲料发酵品质和霉菌毒素含量的影响

Effects of lactic acid bacteria and calcium propionate on fermentation quality and mycotoxin contents of whole plant maize and oat silages

为研究乳酸菌及丙酸钙对全株玉米和燕麦青贮饲料发酵品质、营养品质、微生物数量、霉菌毒素含量及有氧稳定性的影响,利用蒸馏水(CK组)、复合乳酸菌(LAB组,添加量为5×10^(5) CFU·g^(-1)鲜样)、丙酸钙(PACA组,添加量为鲜草重的0.4%)以及乳酸菌和丙酸钙复合(LAB+PACA)分别添加进全株玉米和燕麦原料中青贮120 d。结果表明:全株玉米青贮饲料发酵品质优良而萎蔫后的燕麦青贮丁酸和氨态氮含量较高。添加剂在不同青贮饲料中表现不同。所有添加剂均显著提高了燕麦青贮饲料的乳酸和乙酸含量,降低了pH值、氨态氮、丁酸含量和酵母菌数量(P<0.05)。而PACA和LAB+PACA组则显著提高了玉米青贮饲料中的淀粉和可溶性碳水化合物含量和有氧稳定性并且降低了霉菌和酵母菌数量(P<0.05)。LAB和LAB+PACA的使用有效降低了玉米青贮饲料中的黄曲霉毒素B1含量(P<0.05)。在两种青贮饲料中丙酸含量只有PACA和LAB+PACA组能够显著增加。因此,添加剂尤其是LAB+PACA的复合添加对于提高玉米和燕麦青贮饲料的青贮品质和安全性具有重要作用。

This study evaluated the effects of compound lactic acid bacteria inoculants and calcium propionate on the fermentation quality,chemical composition,microbial counts,mycotoxin contents and aerobic stability of whole plant maize and oat silages.The two forages,whole plant maize and oats,were ensiled for 120 days in an experiment with four treatments:a control treatment(CK),addition of compound lactic acid bacteria(LAB treatment),addition of calcium propionate(PACA treatment)and addition of a combination of LAB and PACA.The application rates of LAB and PACA group were separately 5×10^(5) CFU·g^(-1) and 0.4% of the fresh material.It was found that the fermentation quality of maize silages was very good while for oat silages the butyric acid and ammonia nitrogen contents were very high after storage.The effects of the additives on the silage quality of whole plant corn and oat silages were varied.All additives significantly increased the lactic acid and acetic acid contents and decreased the pH value,butyric acid,ammoniac nitrogen contents and yeast counts of oat silages(P<0.05).While the PACA and LAB+PACA treatments showed better aerobic stability,significantly increased starch and soluble carbohydrate contents and decreased the mould and yeast counts of the whole plant maize silage(P<0.05).The aflatoxin B1 content was reduced by the LAB and LAB+PACA treatments only in the maize silage(P<0.05).The propionic acid content was only increased by the PACA and LAB+PACA treatments,but this effect was seen in both the whole plant maize and oat silages.Therefore,the combination of LAB and PACA treatments provides an important improvement in silage quality for whole plant maize and oat silages.