Study On The Keep-alive Transportation Technology For Bream

In this paper,the effects of fish water quality ratio,water temperature,MS-222,clove oil and CO₂ anaesthetic on the survival transport of bream were studied.In order to find out the technical parameters suitable for water transportation of bream,extend the transportation time of bream and improve the survival rate of bream,so as to reduce the loss of bream transportation and obtain the maximum economic benefit as much as possible.The main research contents and results are as follows:The preservation effect of bream in different concentrations of MS-222 anesthetic solution on the survival rate was studied,including the changes in behavior and respiratory rate during different anesthesia and recovery processes,and in different concentration of MS-222?40,60,80,100 mg/L?,different water temperature?2,7,15and 20??,quality of different fish-water ratio?2,1,1,1,1,3,1:5?bream fish survival.The results showed that the longest survival time and the highest survival rate were obtained when the concentration of anesthetic solution was 60 mg/L,the temperature of water was 7?and the ratio of fish to water was 1:3.With the extension of the keep-alive time,the content of ammonia nitrogen,microorganism and pH in the water index showed an upward trend,while the dissolved oxygen decreased.The glycogen and pH in the muscle decreased,and the content of lactic acid increased in the fish index.Lactic dehydrogenase,aspertate aminotransferase,blood glucose,urea and creatinine were significantly increased in the blood index?P<0.05?,but the change were smaller than those of the control group.Studies have shown that the anesthetic MS-222could be used properly to prolong the survival time and improve the survival rate of the bream.The effect of clove oil on the live transportation of bream was studied in this paper.Based on the single factor experiment,the optimum condition of preserving transportation was determined by orthogonal experiment,and the changes and effects of water quality indicators and fish biochemical indicators in live transportation were detected and analyzed.The results showed that the optimum conditions for preservation and transportation were the anesthetic solution concentration of 15 mg/L,water temperature of 9?and fish-water ratio of 1:3.The survival time was up to 50 h and the fish survival rate was 100%.In water body indexes,there was no significant change in pH and dissolved oxygen.The ammonia nitrogen in the anesthesia group increased from0.05 mg/L to 4.03 mg/L within 48 h.The microorganisms in the water increased significantly within 24 h.The increase of ammonia nitrogen and the growth of microorganisms would affect the survival of fish.In the biochemical indexes of fish body,the glycogen content in muscles of anesthesia group decreased significantly within 24 h.The content of lactic acid increased significantly and then decreased,and the pH decreased first and then increased,indicating that the glycogen consumption produced lactic acid in the transportation of alive fish.Among the blood indexes of fish body,AST activity,LDH activity,urea and creatinine?CREA?increased after 12 h,and then increased significantly within 36 h?P<0.05?,and then decreased in the anaesthetic group.The results showed that the metabolic level of liver and kidney tissue was affected by the prolongation of survival time.The effect of CO₂ on the live transportation of bream was studied in this paper.The concentration of CO₂ anesthetic solution?0,60,120,180,240 mg/L?;water temperature?4,9,15,20,25°C?and fish water quality ratio?2:1,1:1,1:3,1:5?based on the single factor test,three factors of fish water quality ratio,water temperature and anesthetic concentration were determined to optimize the survival time of the bream,and the changes and effects of water quality indicators and fish biochemical indicators in live transportation were detected and analyzed.The results showed that the optimum conditions for preservation and transportation were the anesthetic solution concentration of 90 mg/L,water temperature of 9?and fish-water ratio of 1:3.The survival time was up to 46 h and the fish survival rate was 100%.In water body indexes,there was no significant change in pH and dissolved oxygen.The ammonia nitrogen in the anesthesia group increased from 0.07 mg/L to 4.79 mg/L within 48 h.The microorganisms in the water increased significantly within 24 h.The increase of ammonia nitrogen and the growth of microorganisms would affect the survival of fish.In the biochemical indexes of fish body,the glycogen content in muscles of anesthesia group decreased significantly within 24 h.The content of lactic acid increased significantly and then decreased,and the pH decreased first and then increased.Among the blood indicators of fish body,AST activity,LDH activity,urea and CREA increased after 12 h,and blood glucose?GLU?increased significantly in the anesthetic group?P<0.05?.