Optimized Condition Of Pineapple Residue Silage And Its Effects On Rumen Fermentation Characteristics Of Leizhou Goat In Vitro

Based on the abundant land resources,in this study,the effects of different additives on the silage quality of pineapple residue and the degradation characteristics of Leizhou goat rumen in vitro were studied by using pineapple residue as the raw material,and further investigated the best type of pineapple residue silage agent as well as its proper added concentration and the feasibility of the new type of feed resources in Leizhou goat.The study included three experiments primarily.Experiment 1:Study on optimized condition of pineapple residue silage.Pineapple residue was used as raw material in this experiment,which was divided into13 groups:Conventional silage group?Control:CG?,Cellulase-added group(A1:0.15g·kg^-1?A2:0.3 g·kg^-1?A3:0.6 g·kg^-1),Lactobacillus-added group(B1:0.025 g·kg^-1?B2:0.05 g·kg^-1?B3:0.1 g·kg^-1),EM bacteria-added group(C1:24 ml·kg^-1?C2:48 ml·kg^-1?C3:96 ml·kg^-1),Cellulase+Lactobacillus-added group?A1+B1?,Cellulase+EM-added group?A1+C1?and Lactobacillus+EM-added group?B1+C1?.Triplicate in each group.After 30 days of silage,nutrient indexes of pineapple residue in each group were determined.The results showed that:1)The addition of A2 and A3 increased the content of CP,RFV,LA and AA of pineapple residue silage?P>0.05?,while decreased pH and WSC?P>0.05?and significantly decreased the value of NDF and NH₃-N/TN?P<0.05?;Content of LA in group A3 was highest,and increased by18.53%,indicated that silage effect is better.2)The addition of B1 markedly improved content of CP in pineapple residue silage?P<0.05?,reduced the value of NH₃-N/TN,WSC and nitrite?P<0.05?,and increased the content of LA and AA?P>0.05?,RFV>100,content of LA increased by 6.95%.3)The addition of C2significantly improved the content of CP and WSC in pineapple residue silage?P<0.05?,while decreased the content of ADF?P>0.05?,reduced the value of NH₃-N/TN?P<0.05?significantly and increased value of lactic acid/total acid?P>0.05?,RFV>100.4)The addition of B1+C1 increased the content of CP and decreased the content of NDF and ADF?P>0.05?,while dramatically reduced value of NH₃-N/TN?P<0.05?and improved RFV?P<0.05?.In summary,the addition of 0.6g·kg^-11 Cellulase,0.025 g·kg^-11 Lactobacillus,48 ml·kg^-11 EM bacteria and combined additive(0.025 g·kg^-1Lactobacillus+24 ml·kg^-11 EM bacteria)could improve the quality and nutrient content of pineapple residue silage.Experiment 2:Study on effects of pineapple residue silage on Leizhou goat fermentation characteristics in vitro.Treatments were divided into 13 groups:CG,A1,A2,A3,B1,B2,B3,C1,C2,C3,A1+B1,A1+C1 and B1+C1 by using pineapple residue silage in 13 groups as fermentation substrate in experiment 1.5 replicates and2 blank control were set up on every time point,and cultured 6,12,24 and 48 hours respectively.The results showed that:1)After 48 h fermentation,GP in A2,B3 and B1+C1 group were significantly higher than those in B2 group?P<0.05?,but there were no significance between other groups?P>0.05?.2)After 6 h fermentation,DMD in A1,A3 and B3 group were significantly higher than those in CG group?P<0.05?.After 48 h fermentation,DMD in A1 and A3 group were markedly higher than those in CG group?P<0.05?.3)During the whole fermentation period,CPD in A2,A3,B1and B2 were higher than those in CG group significantly?P<0.05?,after 48 h fermentation,C2 group was significantly higher than A2,A3 and B1 groups?P<0.05?,and there was no significant difference from B2 group?P>0.05?.4)After 6 h fermentation,NDFD in A2,B3 and B1+C1 group were significantly higher than those in CG group?P<0.05?,however,there were no significance between each group after48 h fermentation?P>0.05?.5)During whole fermentation period,pH and the concentration of NH₃-N in every group were in the normal range.VFA in A3,B1,C2and A1+C1 group were higher than other groups after 48 h fermentation,but there was no difference between those groups and CG group?P>0.05?.In summary,group A3,B1 and C2 increased the content of rumen OMD,NDFD and CPD in vitro,maintained normal pH and concentration of NH₃-N in rumen fermentation,improved concentration of VFA and in vitro fermentation characteristics and nutrient degradation rate of pineapple residue silage.Experiment 3:Study on effects of pineapple residue silage on in vitro rumen microbial flora of Leizhou goat.The study screened rumen fluid in 24 h fermentation in vitro in group A3,B1,C2,and CG in experiment 2.Group CG,A3,B1 and C2were turned into group CG,A,B and C respectively,triplicate in every group and analyzed 16s rDNA?V3+V4?sequence.The results showed that:1)There were no significant difference in Chao1 and ACE index among the treatments?P>0.05?.Simpson index in CG group were markedly greater than that in Group A,B and C?P<0.05?,while Shannon index significantly less than that in group A,B and C?P<0.05?.2)At the level of phylum,Bacteroidetes,Fibrobacteres and Firmicutes were the dominant flora.Bacteroidetes bacteria proportion in group A and B were higher than that in group CG?P>0.05?,and the relative abundance of Firmicutes and Proteobacteria in group A and B were significantly higher than that in group CG?P<0.05?,while relative abundance of Fibrobacteres were markedly lower than group CG?P<0.05?.3)At the class level,Bacteroidia,Fibrobacteria and Clostridia were ascendent flora.Clostridia bacteria proportion in group A and B were higher than those in group CG and C?P<0.05?.At the family level,Prevotellaceae was dominant flora,Prevotellaceae bacteria proportion in group A and B was higher than that in group CG?P>0.05?,and bacteria proportion of Ruminococcaceae,Veillonellaceae and Rikenellaceae in group A were significantly higher than those in the other three groups?P<0.05?.4)At the genus level,Prevotella was the dominant flora.Prevotella bacteria proportion in group B and C were higher than that in group CG?P<0.05?,but there was no significant difference between group A and B?P>0.05?.The bacteria proportion of Anaerovibrio,Rikenella and Ruminococcus in group A were dramatically higher than the other three groups?P<0.05?.In summary,group A,B and C improved diversity of species.Group A and B increased the dominant flora as well as the relative abundance of other flora,which was beneficial to the reproduction of rumen microorganisms and digestion and absorption of feed nutrients.In conclusion,the quality and nutritional value of pineapple residue after silage were improved.Rumen test in vitro showed that it was feasible to feed pineapple residue after silage to Leizhou goats.The addition of 0.6 g·kg-1 Cellulase and0.025g·kg-1 Lactobacillus can effectively improve the ensiling quality and nutritional value of pineapple residue,maintain the normal rumen fermentation,improve the abundance of dominant bacteria in the rumen,and contribute to the growth and reproduction of microorganisms in the rumen and the digestion and absorption of feed nutrients.