Effects Of Dietary Pantothenic Acid Level On Growth Performance,Antioxidant Indices And Lipid Metabolism Of Honey Bee(Apis Mellifera L.)

With the substitute for pollen more and more widely used during the season lacks of nectar,the problem to make balance and scientific bees fodder has to be solved urgently.Considering the honey bee’s natural feed rich in pantothenic acid(PA),the addition of PA to allocation of nutrients in the diet of honey bees is essential.Therefore,it is great significance to explore the nutritional function of pantothenic acid in honeybee and the appropriate level of PA in artificial diet.Exp.1 Research of the appropriate dietary pantothenic acid levels for Apis mellifera ligustica larvae.A total of 1800 one-day-old larvae were randomly assigned to 5 groups with 3 plicates per group and 120 larvae per replicate.Larvae were fed with experimental diet with the following pantothenic acid levels: 0.92 mg/g,1.22 mg/g,1.52 mg/g,1.82 mg/g,2.12 mg/g,until pupation.Sample in 5th and 7th day respectively and measure the body weight,body composition,haemolymph biochemical indices,antioxidant function and the mRNA expression involved with CoA synthesis,then calculate the pupation rate and eclosion rate.The results show that: 1)Dietary pantothenic acid levels could significantly increased the eclosion rate(P<0.05);the fresh and dry body weight increased firstly and decreased subsequently(P<0.05),max in 1.82 mg/g,meanwhile significantly increased the EE(P<0.05);2)With the development of dietary PA,the TP,TCHO,HDL,and LDL content of 5-day-old larvae decreased firstly and increased subsequently(P<0.05),the minimum in 1.82,1.82,1.22,1.52 mg/g respectively.3)The T-AOC of larvae had been significantly increased with the development of dietary PA,as well as the SOD of 5-day-old larvae(P<0.05);4)Dietary PA levels significantly influenced the gene expression of PANK4 and PACDC of 5-day-old worker bee larvae(P<0.05),and both of them reached the maximum in 1.82 mg/g.Considering dry weight of 5-day-old larvae and eclosion rate to fitting curve,the appropriate dietary PA levels for Apis mellifera ligustica larvae were 1.85 mg/g~2.01 mg/g.Exp.2 Research of the appropriate dietary PA levels for adult Apis mellifera ligustica worker bee.The new bees in the bee box were randomly divided into 7 groups,each group had 3 replicates,and were fed with the artificial diet of PA with a level of 0 mg/kg,9.8 mg/kg,19.6 mg/kg,39.2 mg/kg,78.4 mg/kg,147.0 mg/kg,261.30 mg/kg.During the feeding period,the bees were observed every day and the dead bees were removed in time,replaced the diet every day,sample at 3,6,9 days old,detect the bee feed intake,body composition,hemolymph biochemical,antioxidant activity,fatty acid metabolism and gene expression indexin of midgut,fatty acid composition of bee body.The results show that: 1)The content of crude fat was significantly affected by the addition of PA in the diet(P<0.05).The content of crude fat decreased with the increase of the level of PA.2)Compared with the control group,PA add group of 6 days old and 9 days old bee body SOD and AOC were significantly increased(P<0.05),meanwhile MDA of 9 day-old reduced(P<0.05);3)TCHO content of 6 and 9 days of age in the hemolymph had been affected significantly(P<0.05),reduced the content of TG in haemolymph 3,6,9 days old(P<0.05);the content of LDL in the hemolymph at 6 days old increased firstly and decreased secondly.4)Compared with the blank control group,the groups of PA supplementation significantly affect the content of monounsaturated fatty acid in the 3 days old(P<0.05),and the content of polyunsaturated fatty acids in the body was significantly lower than other control group in the 9 days old(P<0.05).5)With the increase of the level of PA,the lipase activity in the midgut of 3,6 and 9 days old showed a trend of increasing first and decreasing second,and reached the maxt at 39.2,9.8 and 39.2 mg/kg,respectively.6)Compared with the control group,the 39.2 mg/kg group expression of ACC gene in the midgut at the age of 6 days old was significantly lower(P<0.05),and had no significant difference among the other groups at 6 days old(P>0.05);gene expression of FAS in the midgut shows the trends of increased firstly and decreased secondly.Considering antioxidant activities of adult Apis mellifera ligustica worker bee to curve fitting,the appropriate dietary PA levels for Apis mellifera ligustica adult were 84 mg/kg~123 mg/kg.In conclusion,the addition of PA in the diet can promote fat metabolism,enhance the body’s antioxidant capacity.The appropriate dietary PA levels for Apis mellifera ligustica larvae were 1.85~2.01 mg/g,meanwhile 84 mg/kg~123 mg/kg for adult Apis mellifera ligustica worker bee.