The Effects Of Dietary Oligomeric Proanthocyanidins Supplementation On The Growth And Oxidative Stress Of Juvenile GIFT Tilapia (Oreochromis Niloticus)

Two trials were conducted to study the effects of oligomeric proanthocyanidins?OPC?on the growth performance,the activities of digestive enzymes,serum biochemical indexes and oxidative stress of GIFT strain Nile tilapia?Oreochromis niloticus?.The growth promotion effect and optimal level of dietary OPC supplementation were investigated.The alleviatation effect of dietary OPC supplementation on GIFT tilapia exposed to dietary cadmium was evaluated.The results of our study might provide a new way for the development of anti-stress additive.1.Effects of OPC on the growth,serum biochemical indexes and hepatopancreas antioxidant ability and body composition of GIFT tilapiaThree hundred GIFT tilapias with an average body weight of?8.25±0.07?g were randomly divided into 5 groups with 4 replicates per group and 15 fish per replicate.Fish were fed 5experimental diets containing different levels of GPC,which were 0?control group?,200,400,600 and 800 mg/kg for 49 days,respectively.The results were showed as following:FBW,WGR,SGR and DFI were significantly increased by OPC supplementation?P<0.05?,FCR was significantly reduced by OPC supplementation?P<0.05?,there were no significant difference among all OPC supplemental groups?P>0.05?.The SR and FR were not significantly different among all treatment groups?P>0.05?.The activities of protease and lipase in intestinal tract were significantly increased by supplementing OPC?P<0.05?,there were no significant difference among all OPC supplemental groups?P>0.05?.The activities of GPT and GOT were significantly affected by supplementing OPC,the lowest value of GPT appeared in 200 mg/kg OPC supplemental group,the lowest value of GOT appeared in 400 mg/kg OPC supplemental group.The content of ALB was significantly increased by supplementing OPC?P<0.05?,there was no significant difference among all OPC supplemental groups?P>0.05?.The levels of TC and LDL-C?except 200mg/kg OPC group?were significantly decreased by supplementing OPC?P<0.05?.The level of TG was significantly decreased and the level of HDL-C was significantly increased by supplementing OPC?P<0.05?,there were no significant difference among all OPC supplemental groups?P>0.05?.The activity of lysozymes were significantly elevated by supplementing OPC?P<0.05?.The level of T-AOC and the activity of CAT were significantly increased by supplementing OPC?P<0.05?.The activity of GSH-Px in 600 mg/kg and 800mg/kg GPC supplemental groups was significantly higher than that in other groups?P<0.05?.The activity of SOD and the content of MDA were significantly affected by supplementing OPC?P<0.05?,the highest value of SOD appeared in 200 mg/kg OPC supplemental group,the lowest value of MDA appeared in 400 mg/kg supplemental OPC group.The content of body protein was increased and the content of body fat was decreased by supplementing OPC?P<0.05?,the content of body moisture and ash were not significantly different among all treatment groups?P>0.05?.It is concluded that OPC could effectively improve growth performance,improve serum biochemical indexes,reduce the content of body fat,improve the content of body protein and improve antioxidant capacity of the GIFT tilapia's hepatopancreas.The optimum dietary OPC supplemental level is 200 mg/kg under this experimental condition.2.Effects of OPC supplemention on oxidative stress in hepatopancreas and intestinal tract of GIFT tilapia exposed to dietary Cd stressTwo hundred and forty GIFT tilapias were randomly divided into four treatment groups with four replicates in each group and 15 fish in each replicate.The four treatment groups were control group?the basal diet?,Cd group?the basal diet+100 mg/kg Cd?,Cd+OPC group I?the basal diet+100 mg/kg Cd+400 mg/kg OPC?and Cd+OPC group II?the basal diet+100 mg/kg Cd+800 mg/kg OPC?,respectively.The trial period was 49 days.With OPC supplemention in diets of GIFT tilapias exposed to dietary Cd stress,the FBW,WGR,SGR and DFI were significantly increased,and the FCR was significantly decreased?P<0.05?.The FR,HIS and SR were not significantly affected.The activities of protease and lipase in intestinal tract were significantly improved,and the activitiy of amylase was not significantly affected by OPC supplemention.The levels of BUN,TC?only Cd+OPC group II?,TG and LDL-C were significantly lowered?P<0.05?,the activities of GOT and GPT were significantly decreased.The level of HDL-C?only Cd+OPC group II?and the contents of VC and VE were significantly increased by OPC supplemention?P<0.05?.The content of hepatopancreas metallothionein was significantly increased by OPC supplemention.The contents of ROS,H₂O₂,NO and MDA were significantly decreased,and the activities of SOD,CAT and GSH-Px?except hepatopancreas Cd+OPC group I?were significantly increased by OPC supplemention?P<0.05?.The levels of T-AOC and GSH,ASA and AHA were significantly increased by OPC supplemention?P<0.05?.All the indexes of above-mentioned were not significantly different between control group and the OPC supplemental groups?P>0.05?.The results indicated that OPC could alleviate the oxidative stress,and improve the serum biochemical indexes and the growth performance of GIFT tilapia exposed to oxidative stress induced by dietary Cd.In conclusion,the optimal OPC level in GIFT tilapia diet could promot its growth and alleviate the oxidative stress induced by dietary Cd.