| Growth performance, feed utilization, body composition, hemolymph biochemical, enzymeactivity and fatty acid compositions were evaluated to determine the requirements of thedietary phosphatidylcholine, cholesterol and n-3HUFA(n-3high unsaturated fatty acid) atdifferent growth stages of Litopenaeus vannamei.The brief summarys are as follows:1. Six diets contenting phosphatidylcholine0%,0.17%,0.51%,0.68%,1.02%and1.36%were confected using formulated with red fish meal, dehulled soybean meal andpeanut meal as the protein source, and fish oil and corn oil as the fat source. Two8-weekfeeding trials were conducted to determine dietary phosphatidylcholine requirments ofwhite shrimp with initial body weight0.70±0.00g (juvenile) and4.25±0.00g (subadult)using these diets. The results showed that dietary phosphatidylcholine level had significanteffect on WG, SGR, FCR and HSI (P<0.05), but had no significant effect on SR of whiteshrimp (P>0.05).Significant differences were found in body composition (P<0.05) ofwhite shrimp except moisture, whole body protein and crude ash (P>0.05). The crude fatof juvenile shrimp had no significant change (P>0.05), but subadult shrimp had increasedsignificantly (P<0.05). The CHOL, TG and LDL along with the phosphatidylcholine offeed showed a downward trend after the first rise, the content of HDL rised increasedgradually. The experiment results showed that the proportion of phosphatidylcholine in thefeeds significantly influenced the serum AST and ALT. The proportion ofphosphatedylcholine in the feeds significantly improved the liver glutathione-S-transferaseactivity, reduced the content of liver malondialdehyde. The content of phosphatidylcholinein the feeds significantly improved lactate gill filament Na+/K+-ATPase enzyme of juvenileshrimp (P<0.05), but subadult shrimp were not infulenced (P>0.05). The content ofphosphatidylcholine in the feeds significantly improved the content of liver EPA, HUFAand n-3HUFA (P<0.05), but the content of linoleic acid had been reduced (P<0.05). Abroken line equation for weight growth showed that the optimum dietaryphosphatidylcholine requirement was determined to be1.03%and0.65%separately forLitopenaeus vannamei in size of0.70g and4.25g.2. Six diets contenting cholesterol0.63%(FM),0.73%(0.05%C),0.81%(0.1%C),0.92%(0.2%C),1.22%(0.4%C) and1.79%(0.8%C) were confected using formulated withred fish meal, dehulled soybean meal and peanut meal as the protein source, fish oil, cornoil and soybean lecithin as the fat source. In addition, two levels of phytosterol supplements0.05%(0.05P) and0.8%(0.8%P) were evaluated. Two8-week feeding trialswere conductd to determine dietary cholesterol requirments of white shrimp with initialbody weight0.61±0.00g (juvenile) and4.25±0.00g (subadult) using these diets. The resultsshowed that dietary cholesterol level had significant effect on WG, SGR and FCR(P<0.05),but had no significant effect on SR and HSI of juvenile white shrimp (P>0.05).The WG,SGR,FCR, SR and HSI of subadult shrimp had no significant effect(P>0.05), but0.05%Cand0.1%C groups had good growth and lower FCR. Significant differences were found inbody composition of juvenile white shrimp except crude protein, crude fat and crude ash(P>0.05), but moisture had significant differences (P<0.05). The moisture, crude proteinand crude ash of subadult shrimp had no significant differences (P>0.05), but crude fat hadincreased significantly (P<0.05),0.05%C and0.1%C groups were significantly higher thanFM group (P<0.05). CHOL, HDL, LDL and liver CHOL significantly associated with thecontent of dietary cholesterol but triglyceride had no significant difference (P>0.05). Theexperiment results showed that the proportion of cholesterol in the feeds significantlyinfluenced the serum AST and ALT (P<0.05). The supplementation of the diets withphytosterols had improved Litopenaeus vannamei WG, therefore, it can partly replacecholesterol. Therefore, a broken line equation for weight growth showed that the optimumdietary cholesterol requirement was determined to be0.85%for Litopenaeus vannamei insize of0.61g. The dietary cholesterol of Litopenaeus vannamei in size of4.25g don’t needto add..3. Seven diets contenting n-3HUFA0.16%,0.48%,0.74%,1.39%,2.39%,2.92%and3.44%were confected using formulated with white fish meal, dehulled soybean meal andpeanut meal as the protein source, and fish oil, corn oil and soybean lecithin as the fatsource. Three8-week feeding trials were conducted to determine dietary n-3HUFArequirements of white shrimp with initial body weight0.50±0.00g (juvenile),4.25±0.00g(subadult) and8.50±0.01g (adult) using these diets. The results showed that dietaryn-3HUFA level had significant effected on WG, SGR and FCR (P<0.05), but had nosignificant effect on SR and HSI(P>0.05). WG and SGR of0.74%and1.39%groups ofjuvenile shrimp had no significant differences (P>0.05), but they were significantly higherthan the others group (P<0.05). FCR of0.74%group appeared minimum value. WG andSGR of0.74%group of subadult shrimp were significantly higher than the control group,0.48%group and3.44%group (P<0.05), but had no significant differences to the othersgroup (P>0.05). WG and SGR of0.74%and0.48%groups of adult shrimp had nosignificant differences, but they were significantly higher than the others group (P<0.05). and crude ash (P>0.05), but crude protein of juvenile shrimp and crude fat of subadult hadsignificant differences (P<0.05). CHOL, HDL and LDL had significant differences(P<0.05), but TG had no significant change (P>0.05). The n-3HUFA content in the feedhad significant effected to the serum polyphend oxidase and malic dehydrogenase,alkalinephosphatase,superoxide dismutase,Na+/K+-ATPase in grills enzymatic activity. The fattyacid composition of tissue had significantly associated with the fatty acid composition offeed. The content of n-3HUFA in the feeds significantly improved the content of tissueEPA, DHA and ARA (P<0.05), reduced the content of tissue PUFA and tail musclesaturated fatty acid (P<0.05). Three broken line equations for weight growth showed thatthe optimum dietary n-3HUFA requirements were determined to be0.89%,0.90%and0.51%separately for Litopenaeus vannamei in size of0.50g,4.25g and8.50g. |
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