Study On The Keep-alive Technology Without Water Of Tilapia Anesthetized By Carbon Dioxide

Tilapia is resistant to low temperature.Tilapia is mainly concentrated in guangdong,guangxi,fujian,hainan provinces.In the demestic,fresh tilapia is the main sales mode.In ordor to meet the demand of consumers for freash water,the transportation of fresh tilapia is piticularly important.At present,tilapia is mainly kept alive with water in our country.But transportation with water exists shortcomings,such as poor loading capacity,high cost,low survival rate. Keep-alive transport without water does not exist the above problem. Anesthesia can reduce the metabolic rate of fish and decrease the demand of people for oxygen.And it can improve the survival rate of fish.Compared with other narcotics,carbon dioxide does not remain in fish.Fish treated by carbon dioxide can be sold in the market at once.Carbon dioxide will not cause harm to humans and the environment.Based on the above background,tilapia was anesthetized by carbon dioxide which is safe and effect.Then tilapia under anesthetic was kept alive without water.The main essential nutrients,blood biochemical perameters,the flavor components of muscle were measured.Then we can learn the effect of keeping alive without water on the main essential nutrients,blood biochemical perameters,the flavor components of tilapia.The main contents and conclusions were as follows: 1. The anesthesia effect of carbon dioxide on tilapiaThis research studied the anesthesia influence of carbon dioxide on tilapia.The experimental results showed that anesthesia time gradually decreased from 570±53s to 169±30s and the recovery time increased from 180±20s to 860±36s with the increase of carbon dioxide concentration from 0.41mg/L to 1.13mg/L.The recovery time of tilapia gradually increased and the recovery rate was 100% with the bath time varied from 4min to 16 min. The anesthesia time of tilapia presented upgrade firstly than descending latter with the temperature of the anesthesia rose from 10℃ to 30℃.Within the above experimental range,tilapia clould reache deep anesthesia.Carbon dioxide is an effective anesthetic which can be used to for anesthesia of fish. 2. Study on the keep-alive technology without water of tilapia anaesthetized by carbon dioxideThis paper studied the effect of the concentrations of carbon dioxide,the temperature of keeing alive,aerobic mode,bath time on survival time and survival rate of tilapia which was kept alive without water.And the concentrations of carbon dioxide,the temperature of keeing alive were selected as three factors,then on the basis orthogonal experiment was made.The experimental results showed that the order of influence on the effect of keeping alive was the concentrations of carbon dioxide> the temperature of keeing alive> bath time.The optimal keep-alive conditions were as follows:the concentration of carbon dioxide is 0.6mg/L,the temperature of keeing alive is 20℃,bath time is 7 min. The survival rate of tilapiia was largest at the above condition.The survival rate of tilapia anaesthetized by carbon dioxide during keeping alive without water for 5 hours was 100%. 3. The variation of blood biochemical indicators in the blood of tilapia anesthetized by carbon dioxide during keeping alive without waterThis research measured the change of blood biochemical indexes of tilapia which was kept alive for 0h,1h,2h,3h,4h,5h. This paper studied the effect of keeping alive without water on the blood biochemical indicators. The content of Cr,BUN,LD and the activity of LDH,GOT,GPT was significantly higher than group B when tilapia was kept alive for 1h,2h,3h,4h,5h.The activity of LDH,GOT,GPT and the content of LD,Cr,BUN of group A was respectively 5.3 times,1.9 times, 4.8 times,once,5.7 times as many as group B when tilapia was kept for 5 hours.4. The variation of the main nutritional components and taste components in the muscle of tilapia anaesthetized by carbon dioxide during keeping alive without waterThe variation of the main nutritional components in the muscle of tilapia anaesthetized by carbon dioxide was kept alive without water(group A) and which was kept alive with water(group B)was studied.The results reflected that tilapia was kept alive for 5 hours.There was no significant difference in the content of crude protein and crude fat between group A and group B.The content of glycogen of group A was 5.96% higher than that of group B. The content of lactic acid of group A was 3.04% lower than that of group B.The variable quantity of the main nutritional components of group A is lower than that of group B.Keeping alive without water was more conductive to maintain the main nutritional components in the muscle of tilapia.The variation of the taste components in the muscle of tilapia anesthetized by carbon dioxide was kept alive without water(group A) and which was kept alive with water(group B)was studied.The results suggested that tilapia was kept alive for 5 hours.The ATP degradation rate of group A was higher than that of group B,and the content of IMP which can enhance the flavor of group A was 50.3% higher than that of group B,the content of Hx with bitter taste of group A was 2.4 times lower than that of group B.There was no significant difference in HxR content between group A and B(<5%). There was no obvious difference in total free amin acid between group A and B. The succinic acid content of group A was 25% higher than that of group B.The Cl-、Mg2+、Ca2+、PO43-、 K+、Na+ content of group A was respectively 26.8%、17.6%、19.6%、18.7%、12.8%、4% higher than that of group B.The losses of inorganic ions of group A were lower than those of group B.The taste components in the muscle of tilapia during keeping alive without water were significantly better than those during keeping alive with water.