Effects Of Several Additives On Growth Performance, Serum Non-Specific Immunity And Disease Resistance Of White Shrimp (Litopenaeus Vannamei)

Exp.1Effects of supplemental Azomite in diets on growth, immunefunction and disease resistance of white shrimp (Litopenaeusvannamei)A6-week feeding trial was conducted to study the effect of supplemented Azomite,a natural mineral of volcanic ash and ancient marine deposits, in diet on growthperformance, digestive enzyme activities, serum non-specific immune and diseaseresistance of white shrimp (Litopenaeus vannamei). Graded levels of0%(controlgroup),0.2%,0.4%,0.6%,0.8%Azomite were supplemented in basal diet to obtain5diets. Each diet was randomly fed to four cages of shrimp with initial average weight4.55±0.15g in20cages (2.5m×1.2m×1m). Compared with control group, weightgains of shrimp fed with0.2%and0.4%Azomite diets were increased by13.98%and10.01%(P<0.05), respectively; and protein efficiency ratios were increased by10.38%and8.28%(P<0.05), whereas feed conversion rate decreased by0.11and0.09(P<0.05). There were no significant difference in the contents of muscle moisture,ash, crude fat and crude protein among treatments (P>0.05). In the respect of serumnon-specific immunity, superoxide dismutase activity was increased by0.2%Azomiteaddition, and alkaline phosphatase activity was increased by0.4%and0.6%Azomiteaddition (P<0.05). Shrimp fed with diets supplemented with0.2%-0.8%Azomite hadsignificantly higher activities of lysozyme and phenoloxidase than those of control group (P<0.05). There was no difference in serum MDA among groups (P>0.05). Inthe respect of digestive enzymes, activities of stomach protease and hepatopancreaslipase of0.2%and0.4%Azomite groups, and hepatopancreas protease activity of0.2%Azomite group were significantly higher than those of control group (P<0.05).In the trial of hypoxia stress, the initial lethal time, half lethal time and complete lethaltime of shrimp were all lageed by the addition of0.2%、0.4%and0.6%Azomitecompared with control group. The cumulative mortality rate of0.4%Azomite groupwas significantly lower than that of control group after the injection of Vibrioalginolyticus in the muscle of shrimp. Results above showed that the addition ofAzomite in diet may improve the growth performance, digestive enzyme activities,serum nonspecific immune and disease resistance ability of white shrimp. The properdose ofAzomite in diet is suggested to be0.2%-0.4%for white shrimp.Exp.2Effects of polysaccharides, oligosaccharides and protease ongrowth performance, digestive enzyme activities and serumnonspecific immune of white shrimp (Litopenaeus vannamei).A6-week feeding trial was conducted to study the effect of supplementationpolysaccharides, oligosaccharides and protease in diet on growth performance, serumnonspecific immune and digestive enzyme activities of white shrimp (Litopenaeusvannamei). Graded levels of0.0%(control group),0.2%β-glucan,0.05%astragaluspolysaccharides,0.4%mannan oligosaccharides and175mg/kg protease PT wassupplemented to diet. Each diet was randomly fed to four cages of white shrimp withinitial average weight4.55±0.08g in20cages（2.5m×1.2m×1m）. Compared withcontrol group, weight gain rate (WGR) of shrimp fed with0.2%β-glucan,0.4%mannan oligosaccharides and175mg/kg protease PT were increased by16.19%,12.78%,11.25%(P<0.05), protein efficiency ratio were increased by8.67%,8.32%,8.04%(P<0.05); whereas feed conversion rate (FCR) were decreased by0.10,0.09,0.09(P<0.05). There were no significant difference in the contents of muscle moisture,ash, crude fat and crude protein among treatments (P>0.05). In the respect of serumnonspecific immunity, phenoloxidase were significantly increased by all additivesgroup compared with control group (P<0.05), but no differences was found in thecontent of MDA among groups（P>0.05）. Shrimp fed with diet adding0.4%mannanoligosaccharides had a significantly higher lysozyme and alkaline phosphatase activity,meanwhile activities of superoxide dismutase by supplementation0.2%β-glucan and0.4%mannan oligosaccharides were enhanced compared with control group (P<0.05). In the respect of digestive enzymes activities, the hepatopancreas protease by adding0.05%astragalus polysaccharides and175mg/kg protease PT, intestine protease by175mg/kg protease PT, stomach protease by0.2%β-glucan and0.4%mannanoligosaccharides, hepatopancreas lipase by0.2%β-glucan,0.4%mannanoligosaccharides and175mg/kg protease PT were all significantly increased comparedwith control group (P<0.05). Results above showed that the addition of0.2%β-glucanand0.4%mannan oligosaccharides in diet could improve the growth performance,serum nonspecific immune and digestive enzyme activities; addition of175kg/kgcould improve the weight gain rate and digestive enzyme activites; addition of0.05%astragalus polysaccharides had no influence in weight growth rate, serum nonspecificimmune and digestive enzyme activities.Exp.3Effects of mixtures of β-glucan, mannan oligosaccharides, orcitric acid, Azomite on growth performance, serum nonspecificimmune and disease resistance of white shrimp (Litopenaeusvannamei).A6-week feeding trial was conducted to study the effect of supplementationcompound β-gluan, mannan oligosaccharides, citric acid and Azomite in diet ongrowth performance, serum nonspecific immune and digestive enzyme activities ofwhite shrimp (Litopenaeus vannamei). Graded levels of0.0%(control group, F0),0.4%mannan oligosaccharides+0.4%Azomite (F1),0.4%mannan oligosaccharides+0.3%citric acid (F2),0.2%β-glucan+0.3%citric acid (F3),0.2%β-glucan+0.4%Azomite (F4) was supplemented to diet. Each diet was randomly fed to fourcages of white shrimp with initial average weight4.55±0.08g in20cages（2.5m×1.2m×1m）. Compared with control group, weight gain rate (WGR) of F1, F4were increased by16.24%、13.61%(P<0.05), whereas feed conversion rate (FCR)were decreased by0.11,0.09. There were no significant difference in the contents ofmuscle moisture, ash, crude fat and crude protein among treatments (P>0.05). In therespect of serum nonspecific immunity, phenoloxidase were significantly increased byall additives group compared with control group (P<0.05). Activites of lysozyme withF1were significantly enhanced (P<0.05), while content of MDA were significantlydecreased (P<0.05). Shrimp of F1and F2had a significantly higher alkalinephosphatase activity, meanwhile activities of superoxide dismutase by F1and F4wereenhanced compared with control group (P<0.05). In the respect of digestive enzymes, activities of hepatopancreas protease, intestine protease, stomach protease andhepatopancreas lipase with F1and F4were significantly higher (P<0.05). In the trialof hypoxia stress, the initial lethal time, half lethal time and complete lethal time ofshrimp were lageed by all composite additives. The cumulative mortality rate of alladditives group was significantly lower than that of control group after the injection ofV.alginolyticus in the body of shrimp (P<0.05). Results above showed that theaddition of0.4%mannan oligosaccharides+0.4%Azomite,0.2%β-glucan+0.4%Azomite in diet could improve the growth performance, serum nonspecific immune,digestive enzyme activities and disease resistance ability; addition of0.4%mannanoligosaccharides+0.3%citric acid,0.2%-glucan+0.3%citric acid could improve theability to resist V.alginolyticus and low oxygen of white shrimp.