| The experiment was conducted to study the effects of mix-ensiling of different ratios of pine needle and alfalfa on silage quality to screen the appropriate proportion of alfalfa and pine needles, to determine the the change of main microorganisms and mycotoxin(aflatoxins, zearalenone and vomitoxin)content of mix-ensiling of pine needle and alfalfa,At the same time, to investigate the effect of pine needle and alfalfa Mixed Silage on in vitro rumen fermentation parameters.The experiment was designed including 4 treatment. The pine needles and alfalfa were mixed to silage by 1:9(group H1), 3:7(group H2), 5:5(group H3)as treatment groups,and alfalfa silage was control group(group M).There were 3 replicates in each treatment. The mixed silage was ensiled in fermentation tank,and was sampled on 1,3,5,7,14 and 30 days.Experiment 1: The experiment was conducted to evaluat the effects of mix-ensiling of different ratios of pine needle and alfalfa on silage quality. Silages samp les were analyzed for p H value,ammoniacal nitrogen(NH3-N),lactic acid(LA), water soluble carbohydrate(WSC) and aerobic stability on 1,3,5,7,14 and 30 d, to investigate dynamic change of silage quality. Results showed that water soluble carbohydrate and p H value of treatment groups were all declined, at the same time, ammoniacal nitrogen and lactic acid were ascending with the time prolonging. But after 7 days, p H value of control group were ascending while its lactic acid were declined. At the end of Silage, p H value, ammoniacal nitrogen and butyric acid of treatment groups were significantly lower than that in control group(P<0.05). Meanwhile,water soluble carbohydrate, lactic acid, acetic acid and propionic acid in treatment groups were significantly higher than that in control group(P<0.05). The aerobic stability of each group respectively was: group M was 120 h, group H1 was 356 h, group H2 was 552 h and group H3 was 648 h. Compared with group M, the aerobic stability of group H1 was increased by 236 h, group H2 was increased by 432 h,and group H3 was increased by 528 h. Exposure to oxygen for eighth days,p H of the three treatment groups increased significantly less than the control group(P<0.05),and the number of yeasts and molds were significantly less than the control group(P<0.05). The effect of the interaction of the proportion and the mixed silage time on NH3-N, the p H and the number of yeast was extremely significant(P<0.01),and its impact on the content of lactic acid was significantly(P<0.05). By comprehensive evaluating, The mixing effect of 3:7 and 5:5 ratio were both better.Experiment 2: The experiment was conducted to assess the the change of main microorganisms and mycotoxin content of mix-ensiling of pine needle and alfalfa. Silages samples were analyzed for the quantity of lactic acid bacteria, mold, yeast and aerobic bacteria,and for the content of aflatoxins(AFT), zearalenone(ZEN) and vomitoxin(DON)on 1,3,5,7,14 and 30 d.The results showed that, with the time prolonging,the quantity of lactic acid bacteria, mold, yeast and aerobic bacteria were climb up and then declined,a nd the trend kept at a low level after 7days,and the amount of lactic acid bacteria were far far less than that of mold, yeast and aerobic bacteria.The content of aflatoxins, zearaleno ne and vomitoxin were accumulated with the time prolonging. The increasing range of the three mycotoxins in the treatment groups were significantly lower than that in control group(P<0.05).With the increase of the proportion of pine needles, the quantity o f lactic acid bacteria, mold, yeast and aerobic bacteria and the three mycotoxin cumulant and increasing range showed a decrease trend. The result of this test showed that pine needles can inhibit harmful microbial growth in silage, reduce the content of mycotoxins, and increase the safety of silage.The effects of the interaction of the proportion and the mixed silage time on all items was significant(P<0.05) or extremely significant(P<0.01) except aerobic bacteria.Experiment 3: The experiment was conducted to estimate the effects of mix-ensiling of Pine Needle and Alfalfa on in vitro rumen fermentation quality. Pine needles and alfalfa silage were storaged at 30 days as substrate, gas production in vitro, p H, dry matter loss, ammonia nitrogen, volatile fatty acids(acetic, propionic, butyric acid), cellulase activity and other indicators were mesured. The results showed that each treatment group in vitro degradation of p H,gas production,dry matter loss and ammonia nitrogen content were significantly lower than that in group M(P<0.05). Acetic acid content increased with the decrese in the proportion of pine needles, and that in group H2 and group H3 were significantly lower than group M(P<0.05). Acetic acid content in group H1 was less than group M, which difference was not significant(P>0.05). Propionic acid content of each treatment group was higher than group M, and the difference was significant(P<0.05).Cellulase activity of group H1 was significantly higher than group M(P<0.05), cellulase activity of group H3 was significantly lower than group M(P<0.05). In the treatment groups, the cellulase activity of group H1, H2 and H3 were as follows: group H1 was 4.59(U/g), group H2 was 2.95(U/g), group H3 was 1.42(U/g), the difference was significant(P<0.05).Pine needles mixed with alfalfa silage could reduce p H, dry matter disappearance rate,gas production, ammonia nitrogen and acetic acid content, improve the content of propionic acid. The mixed silage of pine needles and alfalfa were conductive to the growth of rumen microorganisms, reducing the decomposition of dietary protein. The mix-ensiling of pine needle and alfalfa can reduce the activity of cellulase and dry matter disappearance rate in ratios of 3:7 and 5:5. It showed that pine needles in the diet should not be more than 10%,or it will reduce the fiber digestibility. |
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