| In this paper,the frequency and feeding level of paralichthys olivaceus are discussed on the effects of artificially bred paralichthys olivaceus on its growth,intestinal structure,digestive enzyme activity and immuno-related enzyme activity.The main research contents are as follows:1.Effect of feeding frequency on paralichthys olivaceus growth,intestines and enzyme activity.Under water-farming conditions,paralichthys olivaceus(average initial weight is(298.26±10.83 g),with an average initial body length of(29.35 ±3.72 cm)studies were conducted on the amount of feeding,growth,digestive enzyme activity,antioxidant enzyme activity and intestinal tissue structure under different feeding frequency,with the aim of exploring the optimal feeding frequency of paralichthys olivaceus.The experiment set up 3 control groups,the experiment lasted 60 days.The results showed that the daily intake in T3 was significantly larger than that of T2 and T4 groups(P<0.05),and there was no significant difference in specific growth rate and survival rate in T2 and T3,and both were significantly higher than that in T4(specific growth rate: P<0.05,survival rate: P<0.01),there was a significant difference in weight gain between T3(P<0.05),hydrogen peroxide enzymes(CAT),total superoxide dismutase(T-SOD)and lipase(LPS)in T2 and T3,but significantly higher than in T4(CAT,LPS: P<0.01,T-SOD: P<0.05);There was a significant difference in 3 groups of gastro proteinase(PPS)(P<0.05),T3,T2,T4 decreased in turn,and T4 had a decrease in intestinal wall thickness,Longitudinal muscular thickness and Goblet cell were significantly lower than between T2 and T3 groups(P<0.01),but there was no significant difference between T2 and T3;Combined with the results of research and the actual aquaculture,under the conditions of flow aquaculture,the most suitable feeding frequency in the process of paralichthys olivaceus cultivation is 3 times a day.2.Effects of different feeding levels on paralichthys olivaceus growth and enzyme activity.The paralichthys olivaceus with an average initial weight of(308.71 ±7.61)g and an average initial body length of(31.21±0.82)cm were studied for effects on its growth,digestive enzyme activity and immuno-related enzyme activity(daily feeding was 0.5 %,1 %,2 %,3 %,and 4 % of body mass).The experiment was carried out in the flow aquaculture system and lasted for 60 days.The experimental results showed that the feeding level had a significant effect on the weight gain rate(WGR),specific growth rate(SGR),survival rate(SR)and feed coefficient(FCR)of paralichthys olivaceus(P<0.05).There were significant differences in weight gain rates between A.5,A1 and A2(P<0.05),and there was no significant difference in weight gain between A3 and A4,but they were significantly higher than A.5 and lower than A1 and A2.There was no significant difference in feeding rates between A.5,A1 and A2,and no significant differences between A3 and A4,but they were significantly lower than the other three groups(P<0.05).There was no significant difference in specific growth rates between A1,A2 and A3,no difference between A.5 and A4,but they were significantly lower than the other three groups(P<0.05).There was no significant difference in feed coefficients between A.5,A1 and A2,and no significant differences between A3 and A4,but significantly higher than the other three groups(P<0.05).There was no difference in survival rates between A.5,A1 and A2,and no differences between A3 and A4,but they were significantly lower than the other three groups(P<0.05).Feeding levels have significant effects on Lipase,Pepsase,Trypsin,Lysozyme,Hydrogen Peroxide Enzyme(CAT),and Total Superoxide Dismutase(TSOD).Intestinal lipase activity in A.5 was significantly higher than the others,and in A4 lipase activity was significantly lower than the others(P<0.05).There were significant differences in pepsase activity between A.5,A1 and A2(P<0.05)and decreased in turn,and there was no significant difference in pepsase activity between A3 and A4(P>0.05),and were significantly lower than the others.There was a significant decrease in trypsin activity among A1,A3 and A4,and were significantly lower than in A.5 and A2(P<0.05),and there was no significant difference in trypsin activity between A.5 and A2(P>0.05).There was no significant difference in lysozyme activity between A.5 and A1(P>0.05),decrease in lysozyme activity in A4,A3,and A2.There was no significant difference in hydrogen peroxide activity between the A1 and A2 groups(P>0.05),and the hydrogen peroxide activity of A4 was significantly higher than A3(P<0.05);A2 and A3 were significantly higher than the others.There was no significant difference in hyperoxide dismutase activity between A2 and A3,and the activity of superoxide dismutase decreased in A4,A1 and A.5,and the difference among A4,A1 and A.5 was significant(P<0.05). |
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