| Effect of fermented cassava residue and different nutrition level on fattening Hu lamb were investigated by using feeding experiment and digestion and metabolism experiment in order to provide a theoretical basis for the rational use of fermented cassava residue and scientific reference for fattening Hu lamb.This thesis included the following four parts:Experiment one:To evaluate the optimal fermented cassava residue replacement ratio of energy source ingredients(corn)in diets of Hu lamb at 4 months of age.(Method)48 healthy Hu lambs with close body weight(24.15±1.54kg)were randomly divided into 4 groups with 3 replicates(4 lambs in every replicate)and fed diets with 0(Control group),20%(group A),40%(group B),and 60%(group C)of fermented cassava residue in respective diets to replace corn.Lambs were weighted and sampled to measure the growth performance,serum biochemical indices and four lambs were killed to measure the carcasses traits,and meat quality.(Result)The results showed that:1)The feed intake of lambs in Group A was significantly higher than that of Group B and control group(P<0.05).The average daily weight gain had an increased tendency from Group A,Group B to Control group(0.05<P<0.10).Meanwhile,both Group A and B had an improved ratio of feed to body weight gain compared with control group.However,lambs in Group C had a bad physical condition.2)The carcasses traits,meat quality,and serum biochemical indices all showed no difference among each group(P>0.05).(Conclusion)The optimal replacement of corn with fermented cassava residue in Hu lamb's diet is 20%(As Fed),and the feed cost in this amount is also saved.Experiment two:The study was to investigate the effects of different proportion of fermented cassava residue on the digestion and metabolism of Hu lamb.In total,9 four-month-old Hu lamb with health and similar body weight were randomly divided into three groups,which were then denoted as control group(basal diet),group A(containing 20%diet replacing part of corn feed),group B(containing 40%diet replacing part of corn feed).Then nutrient digestion and metabolism indices were determined.The results showed that ammonia concentration in control group and group A was significantly higher than group B(P<0.05),while acetic acid and butyric acid concentration of rumen in contract group were greatly increased than the other two groups(P<0.05).A significant reduction of DM and CP digestibility in group A and B was observed when compared with that of the control group(P<0.05).ADF digestibility of group B was significantly lower than the other two groups(P<0.05),while in term of NDF digestibility,there was no significant differences among three groups(P>0.05).Nitrogen retention rate in the control group was significantly higher than other two groups(P<0.05).The same result was found when determining the energy digestibility.In conclusion,the effect of the use of nutrition in Hu lamb was lower than the control group when fed diets containing fermented cassava residue.Experiment three:The aim of this study was to investigate the effect of different nutrition level diets on fatting Hu lamb.In total,40 Hu lambs with health and similar body weight(18.35± 1.39 kg)were randomly divided into four groups,which were then denoted as control group(containing 8.40 MJ/kg metabolic energy and 12.84%crude protein),high protein group A(containing 8.68 MJ/kg metabolic energy and 15.33%crude protein),high energy group B(containing 9.70 MJ/kg metabolic energy and 13.05%crude protein),high protein and high energy group C(containing 9.66MJ/kg metabolic energy and 15.44%crude protein).The growth performance,blood biochemistry index were determined after feeding for 60 days and three lambs of each group were killed to measure slaughter performance and meat quality.The results showed that the average daily gain in the three experimental groups were significantly higher compared with the control group(P<0.05).The serum total protein concentration in group C were higher than that of other three groups(P<0.05).Moreover,the serum urea nitrogen concentration in control group and group B were greatly lower compared with that in group A and C,and group C had the highest concentration(P<0.05).In addition,the water loss rate was significantly decreased in other three experimental groups when compared with that of control group(P<0.05).In conclusion,the improvement of dietary protein levels or energy levels or improving the both levels can significantly increase the growth rate of Hu lamb,and have an effect on the related indicators of protein metabolism or energy metabolism in blood.However,the concentrations are in the normal range.In addition,improving feed nutrition levels can significantly improve water holding capacity and meat quality.Experiment four:The aim of this study was to investigate the effect of different nutrition levels on the digestion and metabolism in Hu lamb.In total,12 four-month-old Hu lamb with health and similar body weight were randomly divided into four groups,which were then denoted as control group,high protein group A,high energy group B,high protein and high energy group C.Then nutrient digestion and metabolism indices were determined.The results showed that significant differences of rumen pH were observed in control group and group A(P<0.05).The ammonia concentration in group B was lower than that of other groups(P<0.05).The same trend of changes in the acetic acid and butyric acid concentration of rumen were expressed(P<0.05),while no difference was observed between control group and other treatments(P<0.05).The ingested nitrogen,urine nitrogen and nitrogen retention were significantly increased in group A and C(P<0.05).Significant differences were found in energy intake,apparent digestive energy and energy digestibility among all the groups(P<0.05).In conclusion,the effect of use of the nutrients on Hu lamb increased with the improvement of dietary energy and protein levels. |
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