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Inoculant effects on the fermentation quality, chemical composition and saponin content of alfalfa silage in mixture with wheat bran or corn husk
This study evaluated the effects of lactic acid bacteria inoculants on the fermentation quality and chemical composition of alfalfa silage (A), a mixture of alfalfa and wheat bran (A+WB), and a mixture of alfalfa and corn husk (A+CH). The application rates of wheat bran in A+WB or corn husk in A+CH were 10%, 15%, and 20% of the whole fresh material. These different materials were treated with distilled water (control), Lactobacillus plantarum 1 (LAB1), L. plantarum 2 (LAB2), L. plantarum 8 (LAB8) or a commercial inoculant (LALMAND) at a rate of 106 CFU/g of fresh forage. As the application rate of the by-products increased, the dry matter (DM), lactate, propionate, and neutral detergent fibre (after heat-stable amylase treatment) contents increased, and the pH and the acetate, ammonia nitrogen, crude protein, and non-fibre carbohydrate contents decreased. The A+WB showed better fermentation quality than A and A+CH. The inoculants had beneficial effects on the silages, but the effects varied. The results indicate that the use of LAB1, LAB2, or LAB8 was better with A, while LALMAND was preferable for use with A+WB or A+CH. The saponin content decreased during ensiling and was positively correlated with the pH and the acetate and ammonia nitrogen content but negatively correlated with the DM content. The increase in the application rate of by-products and the addition of LALMAND further decreased the saponin content. Overall, the combined effects of the inoculants, by-products, and different application rates improved the fermentation quality and chemical composition and led to greater a reduction of saponin in alfalfa silage, but the selection of suitable types and application rates of by-products and inoculants is essential.
AN16407 Accepted 31 July 2017
© CSIRO 2017