Effects of puerarin on growth performance, serum biochemical indices and liver fat deposition of grass carp

<bold>Objective</bold> This study aims to investigate the effects of puerarin on growth performance，serum biochemical indexes and liver fat deposition，thus providing a scientific basis for the development of functional feed additives to reduce fat accumulation of grass carp. <bold>Method</bold> A total of 360 healthy grass carp with initial body weight of（46.30±0.40）g were randomly divided into 4 groups（3 replicates in each group and 30 fish in each replicate）.Fishes in the control group were fed a basal diet，and the experimental groups were fed the basal diet supplemented with 200，400 and 800 mg/kg puerarin，respectively.The experiment period was 65 days.Growth performance，basic composition of whole fish，serum biochemical indexes，oil red staining and H&amp;E staining sections with genes related to fat metabolism of liver tissues of grass carp were detected respectively after the aquaculture experiment. <bold>Result</bold> （1）Compared with the control group，adding 200 mg/kg puerarin to the diet significantly increased the final body weight（FBW），weight gain rate（WGR）and specific growth rate（SGR） of grass carp（<italic>P</italic>&lt;0.05）；（2）Compared with the control group，adding 400 mg/kg puerarin to the diet significantly reduced the contents of TG，TC，HDL-C and LDL-C in serum of grass carp，while adding 800 mg/kg puerarin to the diet significantly reduced the contents TC and HDL-C in serum（<italic>P</italic>&lt;0.05）；（3）Compared with the control group，adding 400 mg/kg and 800 mg/kg puerarin to the diet significantly reduced the lipid droplet levels in the liver（<italic>P</italic>&lt;0.05），there was no obvious cell damage or nuclear shift in the liver tissue of grass carp.（4）Compared with the control group，adding 200 mg/kg puerarin to the diet only reduced the expression of <italic>fas</italic> in the liver of grass carp，adding 400 mg/kg puerarin to the diet significantly reduced the expression levels of <italic>fas</italic> and <italic>acc1</italic> mRNA，and adding 800 mg/kg puerarin to the diet significantly reduced the expression of <italic>fas</italic>，acc1 and <italic>scd-1</italic>（<italic>P</italic>&lt;0.05）. <bold>Conclusion</bold> Diet with adding Low-dose（200 mg/kg） puerarin could improve the growth performance of grass carp；Diets with adding medium to high-dose（400-800 mg/kg）puerarin could reduce liver fat deposition levels by inhibiting the expression of fat synthesis genes，effectively enhancing the lipid health of grass carp.