Effects Of Dietary Manganese Level On Performance,Fat Metabolism And Bone Development Of Growing Rex Rabbits

This experiment subject studied the appropriate manganese supplementation amount for rex rabbits from 3 months of age to slaughter and growth,and the effects of manganese on production performance,fur quality,digestive metabolism,serum biochemical indexes,lipid metabolism and bone development of growing rex rabbits were studied.In this study,200 3-month-old rax rabbits with similar physical conditions were randomly divided into five groups(A,B,C,D,E),with 40 replicates in each group.They were fed an experimental diet with manganese supplementation levels of 0,5,10,20,40 mg/kg(in the form of manganese sulfate),respectively.Pre-experiment for 7 days.Seven days before the end of breeding,8 animals from each group were selected and transferred to metabolic cages for metabolic experiments.The test results are as follows:1.The manganese supplementation level of dietary manganese has no effect on the average daily feed intake(ADFI)and terminal weight(FBW)of growing rex rabbits(P>0.05),and has an average daily gain(ADG)and feed weight ratio(F/G)had a significant effect(P<0.05).When the dietary manganese supplementation level was 20 mg/kg,the average daily gain(ADG)of the rex rabbit reached the highest value;when the dietary manganese supplementation level was 40 mg/kg,the rex-rabbit feed weight ratio(F/G)reached a minimum.After adding manganese to the feed,the slaughter performance and fur of the rex rabbits had no effect compared with the control group(P>0.05).Manganese addition level can increase the bone hardness of growing rex rabbits(P<0.05)and reached a maximum when the dietary manganese addition level was 20 mg/kg.The dietary manganese supplementation level had a significant effect on the thymus index of rex rabbits(P<0.05),which significantly increased its value.The dietary manganese supplementation levels significantly increased the IGM content in the serum and significantly suppressed the IGA content in the serum(P<0.05).Dietary manganese addition levels significantly affected urine nitrogen,deposited nitrogen,nitrogen use efficiency,and nitrogen biological titer(P<0.05),and when the manganese addition amount in the diet was 20 mg/kg,urine nitrogen reached a minimum,While sedimentary nitrogen,nitrogen use efficiency,and biological nitrogen titer achieved maximum values.Dietary manganese addition levels had no effect on apparent digestibility of dry matter,crude protein,crude fat,crude fiber,calcium and phosphorus(P>0.05),and dietary manganese addition levels had a significant effect on apparent digestibility of manganese(P<0.05).As the amount of manganese added to the diet increased,the apparent digestibility of manganese decreased first and then increased,reaching a maximum when the amount of manganese added to the diet was 20 mg/kg.2.Based on the above test indicators,we selected a test group with a dietary manganese addition level of 0 mg / kg as the control group and a dietary supplementation level of 20 mg / kg as the manganese treatment group.Mechanisms of metabolism.The manganese treatment group significantly reduced the weight of scapular and perigastric fat in growing rex rabbits(P <0.05).Compared with the control group,the manganese-treated group significantly reduced triglyceride levels in rex rabbit serum(P <0.05).Manganese-treated group significantly reduced the expression of FAS and ACC genes in adipose tissue,while increasing the expression of CPT1 gene(P <0.05).Manganese treatment group can also significantly increase the expression of PPARα and PPARγ genes in liver tissues(P <0.05).In summary,the addition of manganese in the diet can promote fat oxidation and decomposition,inhibit fat synthesis and reduce fat deposition in rex rabbits.3.The dietary manganese addition level can significantly increase the rigidity of the bone,and reached a maximum when the dietary manganese addition amount was 20 mg/kg(P<0.05).Dietary manganese supplementation can increase the expression of OPG gene in skeletal tissue,and RANKL/OPG decreased significantly with the increase of dietary manganese addition(P<0.05).Based on the results of the above tests,the appropriate manganese addition level for feeding rex rabbits from 3 months of age to slaughter is 20 mg/kg(the measured value of manganese in this group of diets is 33.19 mg/kg).