| An experiment was conducted to study the effect of vitamin E(VE)and selenium(Se)on the phyiology and biochemistry in cobia(Rahycentron canadum)juveniles by adding different amount of VE and Se in the diets.The cobia juveniles were reared in a shrimp breeding workshop of Guangxi fishery institute located in Qisha,Fangcheng City,Guangxi.1800 cobia juveniles(with initial average body weight about 3 g)from age 26 to 29 d,after 21 d‘'s acclimation,then selected 1155 health juveniles of the same size(with initial average body length about 11cm,with initial average body weight about 9 g).The juveniles were randomly assigned to seven dietary treatments,(n = 3)parallel tanks,there were 21 tanks and each tank had fifty-five fish.The juveniles were fed for 12 weeks from June 15 to 6th September,2009,using one control diet(D-0,do not add the VE and Se)and six treatment diets(D1 to D-6,the VE added as follows:100,80,60,40,20,0 IU/kg of dry diet,of Se added in turn was 0,0.2,0.4,0.6,0.8,1.0 mg/kg of dry diet).The filtered seawater temperature was pH 7.8?8.5,salinity 6.0?29.0‰ and 28.0?32.0? compressed air drive the water.Their round fish,muscle,liver,serum,heart,brain and kidney were taken respectively at week 0,6,12 for freezing in liquid nitrogen,and then stored at-80 ? for analyzing later.Measuring of the nutritional,physiological and biochemical indicators show:(1)With different amount and ratio of VE and Se added,the growth of cobia juveniles was significantly different(P<0.05),and the growth of D-6 was the best,the respectively addition of VE and Se were,0 IU/kg,1.0 mg/kg dry diet.(2)With VE and Se added,no significant difference was found in the survival of cobia juveniles(P>0.05).(3)With VE and Se added,the biochemical ingredients in cobia juveniles from high to low as follows:water>crude protein>crude fat.There was no change about the moisture of round fish at 0,6 weeks,while a significant reduction at 12 weeks,there was also no significant difference between each experimental diet and control diet at 6 and 12 weeks(P>0.05);There was no significant difference between experimental diet and control diet on the crude protein of round fish at 6 and 12 weeks(P>0.05);The crude fat of round fish of both experimental diet and control diet at 6 and 12 weeks was higher than 0 weeks(P<0.05),while there was no significant difference between experimental diet and control diet(P>0.05).(4)Monounsaturated fatty acids(MUFAs)amount in muscle,liver,serum,heart,brain and kidney of cobia juveniles from high to low as follows:C18:ln-9>C20:ln-9,n-3 highly unsaturated fatty acids(n-3 HUFAs):DHA>EPA.The EPA amount of experimental diet in the muscle was lower than the control diet at 6 weeks(P<0.05);while the EPA amount of experimental diet in the muscle was higher than the control diet at 12 weeks(P<0.05).At 6 and 12 weeks,the n-3/n-6 in the liver of experimental diet and the control diet at 6 and 12 weeks was significantly higher than 0 weeks(P<0.05),D-5 was the highest of the PUFAs amount and D-4 was the highest of the n-3 HUFAs amount in the liver.At 6 and 12 weeks,D-5 was the highest of the EPA,PUFAs and n-3 HUFAs amount in the serum.The EPA,PUFAs and n-3 HUFAs amount in the heart of experimental diet and the control diet at 6 and 12 weeks was significantly higher than 0 weeks(P<0.05),while the SFAs and MUFAs amount and the n-3/n-6 in the heart of experimental diet and the control diet at 6 and 12 weeks was significantly lower than 0 weeks(P<0.05),D-1 was the highest of the SFAs amount in the heart.The DHA,PUFAs and n-3 HUFAs amount and the n-3/n-6 in the brain of experimental diet and the control diet at 6 and 12 weeks was significantly higher than 0 weeks(P<0.05),while the EPA and MUFAs amount in the brain of experimental diet and the control diet at 6 and 12 weeks was significantly lower than 0 weeks(P<0.05),D-2 was the highest of the EPA amount and D-3 was the highest of the DHA amount as well with D-1 was the highest of the n-3 HUFAs amount in the brain.The EPA and DHA amount and the n-3/n-6 in the kidney of experimental diet and the control diet at 6 and 12 weeks was significantly higher than 0 weeks(P<0.05),while the SFAs amount in the kidney of experimental diet and the control diet at 6 and 12 weeks was significantly lower than 0 weeks(P<0.05),D-1 was the highest of the SFAs amount and D-5 was the highest of the DHA,PUFAs and n-3 HUFAs amount in the kidney.(5)With different amount and ratio of VE and Se added,the antioxidant capacity and MDA amount of muscle,liver,serum,heart,brain and kidney in cobia juveniles at 6 and 12 weeks wasn't correlated.(6)With different amount and ratio of VE and Se added,the RNA/DNA ratio and weight in the muscle,liver,serum,heart,brain and kidney of cobia juveniles at 6 and 12 weeks was proportionally correlated,therefore,the RNA/DNA ratio can be used as one of the indicators reflect the growth rate of fish. |
PDF Full Text Request