关键词: 再生稻头季, 青贮剂, 青贮品质, 体外瘤胃发酵特性

Abstract:

This experiment was conducted to investigate effects of silage additives on quality and in vitro rumen fermentation characteristics of first season ratoon rice whole-crop silage. The experiment compared three fermentation-enhancing preparations of bacterial and enzyme additives， added at 500 g·t^-1 fresh weight when ensiling whole crop ratoon rice， and a control （CK， 500 g·t^-1 water）. The additive treatments were： N₁， Lactobacillus plantarum （60%）+cellulase （30%）+xylanase （10%）； N₂， L. plantarum （70%）+Enterococcus faecalis （20%）+cellulase （5%）+hemicellulase （5%）； N_3，L. plantarum （30%）+E. faecalis （60%）+cellulase（5%）+hemicellulase （5%）. The silages were sampled after 45 d after ensiling， and the silage quality and in vitro rumen fermentation characteristics analyzed. The results were as follows： 1） After ensiling， the gross energy， total digestible fiber， and acetate values of the N₁， N₂ and N₃ silages were significantly higher than those of CK group （P<0.05）， while the contents of neutral and acid detergent fiber and ammoniacal nitrogen∶total nitrogen of the N₁， N₂ and N₃ groups were significantly lower than those of the CK group （P<0.05）. Among treated silages， the neutral detergent fiber level of the N₂ group was significantly lower than that of N₁ and N₃ groups （P<0.05）. 2） After 24 h in vitro fermentation， the 24 h cumulative gas production， the gas production of rapid degradation and the potential gas production of the N₂ group were significantly higher than for the N₁， N₃ and CK groups （P<0.05）， and the potential gas production of the N₁ group was significantly higher than for the CK group （P<0.05）. The N₁ and N₂ groups had lower pH than the N₃ and CK groups （P<0.05）， and the contents of acetate and ammonia of N₂ group were significantly higher than those of the N₁， N₃ and CK groups （P<0.05）. The propionate contents of the N₁ and N₂ groups were significantly higher than those of N₃ and CK groups （P<0.05）； the acetate∶propionate ratio of the N₂ group was significantly lower than that of N₃ and CK groups （P<0.05）； the degradation rates of dry matter and crude protein of N₂ and N₃ groups were significantly higher than those of N₁ and CK groups （P<0.05）； the degradation rates of organic matter， neutral detergent fiber and acid detergent fiber values of the N₂ group were significantly higher than for N₁， N₃ and CK groups （P<0.05）. In conclusion， it is suggested that silage additives should be supplemented with E. faecalis， cellulase and hemicellulaseunder the premise that L. plantarum is the main agent required to produce first season ratoon rice whole silage with improved nutritional value in actual production.

Key words: first season ratoon rice, silage additives, silage quality, in vitro rumen fermentation characteristics