Effects Of Different Storage Methods On Fish Meal And The Assessment Of Culture Efficiency

The present study were conducted to investigate the effects of different storage methods on fish meal.Litopenaeus vannamei and Epinephelus coioides were taken as the research objects to assess the culture efficiency.The results are presented as follows:1.This experiment was conducted to study the effects of different storage methods(temperature,addition of antioxidant(ethoxyquin,EQ)and storage time)on fish meal freshness.Nineteen groups were formulated by using two-factor experimental design with three storage times(45 d,90 d and 135 d,respectively)and different antioxidant levels(0,300 and 800 mg/kg,respectively)under the condition of room temperature(RT)and 4 oC respectively,fresh fish meal as the control,and investigated the variation of volatile basic nitrogen(VBN),histamine(HA),acid value(AV)and thiobarbituric acid(T BA).The results showed that VBN,AV and TBA of fish meal showed a rising trend with the storage time extended.Under the same storage time,AV and TBA of 4 oC group were lower than those in room temperature group.HA increased at the beginning storage sta ge,then decreased in the later storage period.The supplement of antioxidant benefits to maintain the quality of fish meal.Multiple indexes are needed to comprehensively evaluate the quality of fish meal.2.This experiment was conducted to study the effects of different storage conditions fish meal on growth and physiological effect of Litopenaeus vannamei.Nineteen groups were formulated by using two-factor experimental design with three storage times(45 d,90 d and 135 d,respectively)and different a ntioxidant levels(0,300 and 800 mg/kg,respectively)under the condition of room temperature(RT)and 4 oC respectively,fresh fish meal as the control.A total of 2 280 juvenile Litopenaeus vannamei with an initial body weight of(0.40±0.02 g)were randomly distributed into 19 groups with 3 replicates per group and 40 shrimps per replicate.The experiment lasted for 8 weeks.Specific growth rate(SGR),feed conversion rate(FCR)and protein efficiency ratio(PER)were significantly affected by the interaction of storage time and antioxidant levels(P<0.05),under the condition of 4 oC.The group of 0 mg/kg antioxidant levels in 45 d storage time group had the highest SGR,PER and the lowest FCR.The group of 800 mg/kg antioxidant levels in 135 d storage time group had the highest PER and the lowest FCR.SGR,FCR and PER were significantly affected by the storage time(P<0.05),under the condition of room temperature.The 45 d storage time group had the highest SGR,PER and the lowest FCR.The total antioxid ant capacity(T-AOC)and the activities of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-Px)in hepatopancreas were significantly affected by storage time,antioxidant levels and the interaction of storage time and antioxidant levels(P<0.05).The activitie of TRS and TRS mRN A expression in hepatopancreas were significantly affected by storage time,antioxidant levels and the interaction of storage time and antioxidant levels(P<0.05).Under the condition of this experiment,fish meal stored in different conditions had different freshness.The fish meal freshness could have significant effects on growth,serum biochemical indices and antioxygenic property in Litopenaeus vannamei.With the WGR as evaluation index,the 45 d group stored in a short time is better for the growth of Litopenaeus vannamei.under the condition of 4 oC,high antioxidant level was not beneficial to the growth of Litopenaeus vannamei when fish meal stored for a short time.Under the condition of room tempera ture,storge time was the primary factor of culture efficiency of Litopenaeus vannamei.Litopenaeus vannamei can against poor freshness of fish meal by improving antioxygenic property.3.This experiment was conducted to study the effects of different storage conditions fish meal on growth and physiological effect of Epinephelus coioides.N ineteen groups were formulated by using two-factor experimental design with three storage times(45 d,90 d and 135 d,respectively)and different antioxidant levels(0,300 and 800 mg/kg,respectively)under the condition of room temperature(RT)and 4 oC respectively,fresh fish meal as the control.A total of 1 596 juvenile Epinephelus coioides with an initial body weight of(18.75±0.05 g)were randomly distributed into 19 groups with 3 replicates per group and 28 fish per replicate.The experiment lasted for 8 weeks.The results showed that storage time,storage status and the interaction of storage time and storage status had no significant effects on survival rate(SGR),feed conversion rate(FCR)and protein efficiency ratio(PER)(P>0.05).Weight gain rate(WGR)and specific growth rate(SGR)were significantly affected by storage time(P<0.05)under the condition of room temperature.The WGR and SGR in 45 d group we re significantly higher than 135 d group(P<0.05).Condition factor(CF),viscerosomatic index(VSI)and hepatosomatic index(HSI)were significantly affected by storage time and antioxidant levels(P<0.05)under the condition of 4 oC.The total antioxidant capacity(T-AOC)and the activities of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-Px)in liver were significantly affected by storage time,antioxidant levels and the interaction of storage time and antioxidant levels(P<0.05).The activitie of TRS and TRS mRNA expression in liver were significantly affected by storage time,antioxidant levels and the interaction of storage time and antioxidant levels(P<0.05).Under the condition of this experiment,under the condition of room temperature,storge time was the primary factor of culture efficiency of Epinephelus coioides.Epinephelus coioides can against poor freshness of fish meal by improving antioxygenic property.