| Four groups were set up in the study,corn straw,corncob,sunflower seed hull and rape straw were used as single roughage source of finishing lamb in each group respectively,the proportion was 20%,and the ingredient of concentrate was the same.Each group set up 5 repeatings,each repeating has 6 lambs.The transition period was 14 days;the pre-trial period was 7 days,while the trial period was 70 days.At 42 th day,five lambs were selected from each group for digestion and metabolism test with total decanting method.The apparent digestibility of dry matter,organic matter,neutral detergent fiber,acid detergent fiber,nitrogen and nitrogen retention rate were measured.At the end of trial period,three lambs of each repeating from each group were selected to slaughter,rumen weight and color,rumen volatile fatty acids were measured,and ruminal microflora were analyzed.The slaughter performance was determined,included weight before slaughter,carcass weight and slaughter rate,muscle samples of each lamb was collected to analysis muscle fatty acids.The effects of different roughage sources on production performance and rumen microflora of fattening lamb were studied.The main results as follows:1.Effects of roughage sources on growth performance and nutrient digestion of finishing lamb: Dry matter intake in the corn straw was significantly higher than the other groups(P<0.05).The fininal weight and average daily gain of the corn straw were significantly higher than the rape straw(P<0.05).DM apparent digestibility of the corn cob is significantly higher than the sunflower seed hull and the rape straw(P<0.05);DM and NDF apparent digestibility of the corn straw and the corn cob are significantly higher than the sunflower seed hull and the rape straw(P<0.05).ADF apparent digestibility of the corn straw and the corn cob are significantly higher than the rape straw(P<0.05);Nitrogen digestibility of the sunflower seed hull is significantly higher than the rape straw(P<0.05).Nitrogen deposition rate of the sunflower seed hull,the corn cob and the corn straw are significantly higher than the rape straw(P<0.05).2.Effects of roughage sources on rumen and rumen microflora of fattening lamb:Rumen weight of the corn straw was significantly higher than the other three groups(P<0.05).Rumen color in the sunflower seed hull and the rape straw is lighter,the ratio of valerate and isovalerate in rumen of these two groups were significantly higher than the corn straw and the corncob(P<0.05).The ratio of acetate in rumen of the corn cob was significantly higher than that the corn straw and the rape straw(P<0.05).Rumen microflora richness and diversity in the rape straw was significantly higher than the other groups(P<0.05).The similarity of rumen microflora in each group is low.At the level of phylum,Firmicutes,Bacteroidetes,Spirochaetae,Proteobacteria and Fibrobactereswere the highest abundance in every group(P<0.05).The relative abundance of Firmicutesin the rape straw was significantly lower thanthe other three groups(P<0.05),the relative abundance of Spirochaetae in the corn cob was significantly higher than the rape straw(P<0.05).The quantity of Butyrivibrio fibrisolvens,Fibrobacter succinogenes,Ruminococcus albus and Ruminococcus flavefaciens in the corn cob and the corn straw were significantly higher than the other two groups(P<0.05).3.Effects of roughage sources on slaughter performance and muscle fatty acids of fattening lamb: Weight before slaughter in the corn straw was significantly higher than the rape straw(P<0.05).The slaughter rate and the quantity of polyunsaturated fatty acids in the sunflower seed hull was significantly higher than the corn straw(P<0.05).In conclusion,compared with corn straw,there was no significant effect of corn cob and sunflower seed hull on growth of lamb,and no significant effects of apparent digestibility of DM,OM,NDF,ADF and nitrogen and nitrogen retention rate in the corn cob.Corn cob could be used as a roughage source of finishing lamb.Pape straw could decrease performance of finishing lamb.The species of high abundance rumen microbes of lambs in each group was the same,not only in the level of phylum,but also in the level of genus.Compared with rape straw,corn cob and corn straw could significantly improve the quantity of rumen cellulose of finishing lamb.As roughage source of finishing lamb,sunflower seed hull and rape straw,which made the lamb's rumen color lighter.Compared with corn straw,sunflower seed hull could improve the rate of slaughter and the quantity of polyunsaturated fatty acids in muscle of finishing lamb. |
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