| Iron and zinc are two kinds of indispensable trace elements of fish. Iron and zinc supplement of Carassius auratus gibelio in the practical diets were researched in the study.Experiment I: A feeding trial was conducted to determine the dietary iron supplement of Carassius auratus gibelo with FeSO4·7H2O as the iron source. Levels of iron 100,200,300,400,500 mg·kg-1 were supplied in the practical diets. The five kinds of experimental diets were fed to Carassius auratus gibelio in triplicate aquaria for 54 days. The results showed that:(1)The specific growth rate of weight and length(WSGR, LSGR)and protein efficiency (PE)reached the maximum at 300 mg·kg-1 iron supplement to the praticial diets(the total content of Fe was 1150.78 mg·kg-1 in diet).The regression curve about WSGR was y=-4.7×10-6x2+ 2.83×10-3x +0.22, R2=0.88.When the dietary iron supplement was 301.68 mg·kg-1, WSGR was the largest.(2) No significant difference were obtained for the activitites of SOD, GPT and hemoglobin content of whole blood in all groups (P>0.05), but hemoglobin content increased with increasing dietary iron supplement. The lysozyme (LSZ) activities in phlegm and serum were significant differences (P<0.05), which of the group supplied with 300 mg·kg-1 (total iron feed was 1150.78 mg·kg-1) was highest among the trial groups.(3) The concentrations of iron, copper, manganese and zinc were measured in 14 organs and the results showed that the concentrations of iron in the spleen was maximum, occupied 16.14% of the total contents. Copper in the hepatopancreas, heart and kidneys was the main storage sites, accounting for 14.96%, 14.44%, 12.15% of the total copper contents of the corresponding organs respectively. Manganese in vertebra, spleen, and kidney was the highest, accounting for 11.91%, 11.50%, 11.12% respectively. Zinc in the intestine was the highest, accounting for 22.28%.(4)The results of correlation analysis on the content of the four elements in each organ and different concentration of dietary iron supplement showed that, the ratio of the supplement of iron element represented significant positively correlations with the contents of iron in the kidney and fin, (R=0.91,0.90)(P<0.05); the content of copper in the skull (R=0.88)(P<0.05); the content of manganese in the operculum(R=0.91)(P<0.05)and the content of zinc in the spleen(R=0.93)(P<0.05),but represented significant negatively correlations with the content of copper in the liver(R=-0.88)(P<0.05).Experiment II: A feeding trial was conducted to determine the dietary zinc supplement of Carassius auratus gibelo with ZnSO4·7H2O as the zinc source. Levels of Zinc 60,90, 120,150,180 mg·kg-1 were supplied in the praticial diets. The experimental diets were fed to Carassius auratus gibelio in triplicate aquaria for 54 days. The results showed that:(1) Significant differences appeared to the effects on the growth index, including weight gain,specific growth rate of weight and length(WSGR,LSLR),feed coefficient,PE of Carassius auratus gibelio between each trail group which was supplied with different Fe levels(P<0.05).The regression curve about WSGR was Y = -3×10-5X2 +7.72×10-3X + 223.31×10-3,R2 = 0.701. The supplement of zinc on the basis of maximum WSGR was 128.67 mg·kg-1.(2)The SOD activity in the serum of 120 mg·kg-1 was significantly higher than 180 mg·kg-1(P<0.05), there was no significant difference on CuZn-SOD activity in serum and hepatopancreas in the diets(P>0.05), and the maximum of CuZn-SOD activity was 120 mg·kg-1.The lysozyme activity in phlegm and serum in 120 mg·kg-1 were maximum and the GPT activity in the serum was the minimum, but the corresponding GPT activity in the hepatopancreas was maximum. There was no significant difference of hemoglobin content as the dietary zinc supplement increased (P>0.05).(3)The maximum content of iron, copper, manganese and zinc in the organs were mainly located in the spleen (iron, 15.07%), hepatopancreas (copper, 15.50%) and the heart(copper, 14.80%), spine (manganese, 11.89%), intestine (zinc, 22.29%), respectively.(4) The results of correlation analysis on the content of the four elements in each organ and different concentration of dietary zinc supplement showed that, the ratio of the supplement of Zn element represented significant positively correlations with the content of Cu in the intestine(R=0.94)(P<0.05); represented positively correlations with the content of Zn in the muscle, intestine and ovary, iron in the heart and spleen, were positive(R=0.87, 0.87, 0.86, 0.77, 0.75 respectively)(P>0.05); but represented significant negatively correlations with the content of manganese in the fin(R= -0.97) (P< 0.01)The optimum supplement of iron and zinc in the practical diets were 301.68 mg·kg-1 and 128.67 mg?kg-1, respectively. |
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