Effects Of Several Feed Additives On Growth Performance,immune Response And Intestinal Health Of Litopenaeus Vannamei Fed Diets With Fish Meal Partially Replaced By Soybean Meal

This study was conducted to evaluate the effects of probiotics,tributyrin and glutamine dipeptide complex and fructooligosaccharide on growth performance,immune response and intestinal health of Litopenaeus vannamei fed diets with fish meal partially replaced by soybean meal.1.Effects of probiotics on growth performance,immune response and intestinal health of Litopenaeus vannamei fed diets with fish meal partially replaced by soybean meal720 shrimps were randomly allocated into six groups with three replicates per group and 40shrimps per replicate.Shrimps were fed high fish meal diet?C0:containing 50%fish meal?,low fish meal diet?C:containing 25%fish meal?or the low fish meal diet supplemented respectively with 1.0×10⁸ CFU g^-1Bacillus pumilus SE5?T1?,Psychrobacter sp.SE6?T2?,Enterococcus faecium MM4?T3?or Bacillus claussi DE5?T4?for six weeks.Compared with group C0,lower weight gain rate?WGR?and special growth rate?SGR?and higher feed conversation rate?FCR?were observed in group C,but the differences were not significant.Hemolymph alkaline phosphatase?AKP?and acid phosphatase?ACP?activities of group C decreased significantly?P<0.05?,while superoxide dismutase?SOD?activities showed no significant difference compared with group C0.Compared with group C0,hepatopancreas protease activity in group C decreased significantly?P<0.05?,while lipase and amylase activities showed no significant difference,midgut wall thickness increased significantly while foldings height decreased significantly?P<0.05?.Compared with group C,WGR,SGR and FCR were not significantly affected in all probiotic treatments,hemolymph AKP and ACP activities in the treatments T1 and T3 increased significantly?P<0.05?,hepatopancreas protease and amylase activities increased significantly in the treatments T1 and T4?P<0.05?,while hepatopancreas GOT,GPT activities and malondialdehyde?MDA?levels showed no significant difference in all groups.Compared with group C,midgut wall thickness decreased significantly in all probiotic groups,intestinal foldings height increased significantly in the treatments T1 and T3?P<0.05?,while decreased significantly in the treatment T2?P<0.05?and no significant difference was observed in the treatment T4.It indicated that Bacillus pumilus SE5?T1?,Enterococcus faecium MM4?T3?and Bacillus claussi DE5?T4?play a certain role in improving immune response and intestinal health of Litopenaeus vannamei fed diets with fish meal partially replaced by soybean meal.2.Effects of tributyrin and glutamine dipeptide complex on growth performance,immune response and intestinal health of Litopenaeus vannamei480 shrimps were randomly divided into four groups with three replicates per group and 40shrimps per replicate,the dietary tributyrin and glutamine dipeptide complex levels of the four diets were 0?C:control group,containg 25%fish meal?,0.25%?T1?,0.5%?T2?and 1.0%?T3?.Compared with group C,survival rate?SR?elevated significantly in all treatments?P<0.05?,while WGR and SGR of treatment T3 increased by 33.1%and 55.4%,respectively.The FCR of treatment T3 was significantly lower than the control?P<0.05?.Hemolymph AKP and ACP activities in the treatment T3 increased significantly?P<0.05?,while SOD activities in all treatments showed no significant difference compared with the group C.Compared with group C,hepatopancreas protease,amylase and lipase activities of treatment T3 increased significantly?P<0.05?,while hepatopancreas MDA content of treatment T3 decreased significantly?P<0.05?,hepatopancreas GOT and GPT activities showed no significant difference in the treatment T3 but decreased significantly in the treatment T2?P<0.05?.Compared with group C,midgut wall thickness decreased significantly in all treatments?P<0.05?,and significantly increased intestinal foldings height was observed in the treatments T2 and T3?P<0.05?.The results of PCR-DGGE showed:compared with the control group,uncultured alpha proteobacterium clone XME33 and Vibrio sp.KVD-HL31disappeared in the intestinal of the groups T1,T2 and T3.Vibrio alginolyticus strain also disappeared in the intestinal of the group T3,while Vibrio sp.PID37₁07 disappeared in the intestinal of the group T1 but appared in the groups T2 and T3.It indicated that 1.0%tributyrin and glutamine dipeptide complex could significantly improve the growth performance,immune response and intestinal health of Litopenaeus vannamei.3.Effects of several feed additives on growth performance,immune response and intestinal health of Litopenaeus vannamei fed diets with fish meal partially replaced by soybea n meal1080 shrimps were randomly divided into nine groups with three replicates per group and40 shrimps per replicate,including high fish meal group?C0:containing 25%fish meal?,low fish meal group?C:containing 12.5%fish meal?and seven experimental groups.The seven experimental diets were formulated by adding 0.1%FOS?T1?,0.2%FOS?T2?,0.4%FOS?T3?,1.0%tributyrin and glutamine dipeptide complex?T4?,0.1%FOS+1.0%tributyrin and glutamine dipeptide complex?T5?,0.2%FOS+1.0%tributyrin and glutamine dipeptide complex?T6?,0.4%FOS+1.0%tributyrin and glutamine dipeptide complex?T7?in low fish meal diet,respectively.WGR,SGR and SR of group C decreased significantly?P<0.05?,and FCR increased significantly compared with group C0?P<0.05?.Compared with group C0,hemolymph SOD activity of group C elevated significantly,while ACP and AKP activities showed no significant difference,hepatopancreas protease and amylase activities decreased significantly?P<0.05?,while lipase activities showed no significant difference,hepatopancreas MDA content elevated significantly,while GOT and GPT activities showed no significant difference?P<0.05?,midgut wall thickness increased significantly while intestinal foldings height decreased significantly?P<0.05?.Compared with group C,WGR and SGR of shrimps fed diets T3,T4,T5,T6 and T7 increased significantly?P<0.05?,FCR in groups T3,T4,T6 and T7 decreased significantly?P<0.05?,while SR was no significant difference in all treatments.Except for groups T3 and T7,hemolymph SOD activities decreased significantly in other groups?P<0.05?,AKP and ACP activities in the treatments T3,T4,T5 and T6 elevated significantly?P<0.05?compared with group C.Compared with group C,hepatopancreas protease activities in treatments T4 and T7 and lipase activities in the treatments T3 and T7 increased significantly?P<0.05?,while amylase activities showed no significant difference in all groups,hepatopancreas MDA content in the groups T2 and T6 decreased significantly?P<0.05?,while GOT and GPT activities showed no significant difference in all groups.Compared with group C,midgut wall thickness decreased significantly in all treatments?P<0.05?,and significant increased intestinal foldings height was observed in the treatments T2,T3,T4,T6 and T7?P<0.05?.Compared with single adding groups with the same FOS supplemental level,WGR,SR,hemolymph AKP activity,hepatopancreas protease activity and intestinal foldings height in the combined treatment T6 increased significantly?P<0.05?.In addition,compared with the group T4,hepatopancreas MDA content and midgut wall thickness in the treatment T6 decreased significantly?P<0.05?.The results of PCR-DGGE showed:compared with the control group,Roseobacter sp.SYOP1,Schlegelella sp.KB1a and Endophytic bacterium SV753 disappeared in the intestinal of group C,while Vibrio alginolyticus strain G27 appeared.Compared with the control group Vibrio campbellii strain:JCM 1054 and Vibrio sp.1B12?2008?appeared in the intestinal of groups T1 and T2 and then disappeared in the group T3.Vibrio sp.KVD-HV32 and Vibriothe sp.KVD-HL31disappeared in the intestinal of groups T4,T5,T6 and T7,and Ruegeria marina strain ZH17 appeared in the group T6.The results showed that 0.4%FOS?T3?and 0.2%FOS+1.0%tributyrin and glutamine dipeptide complex?T6?could improve the growth performance,immune response and intestinal health of Litopenaeus vannamei fed diets with fish meal partially replaced by soybean meal.