Study On The Mechanism Of Tilapia With CO-Treatment

Tilapia is one of the most important commercial fish species in South China, with delicious&delicate taste, and nutrient-rich. On the background of the technique of Carbon Monoxide (CO) for Tilapia euthanasia, The aim of this paper was to reveal the transmission of CO from water to fish blood, and to the muscle, along with the changes of tilapia’s physiological and the colour of fillets, in order to further improve the processing of tilapia, endow with good quality of Tilapia products to provide the theory basis. The results are shown as follow:1.Carbon monoxide for tilapia euthanasia:the transmission of CO Quantitative determination of carbon monoxide contents of the water,blood and muscle in the process of Tilapia euthanasia was finished by dual—wavelength spectrophotometry, in order to study the transfer process of carbon monoxide. Which, the CO levels of blood and muscle were expressed in the percentage of carboxy-hemoglobin (HbCO) and carboxy-myoglobin (MbCO), respectively.In the early stage of tilapia euthanasia, CO content of the water was in slow growth, the HbCO level quickly increased in more than90%after a few minutes, but the MbCO content in tilapia muscle was slow growth during this stage. When the process of tilapia euthanasia was carried to medium stage, there has been a turning point, the CO content of the water went up fast, the level of HbCO in tilapia’s blood made no obvious change, while the content of MbCO in tilapia’s muscle began skyrocketing. Most of the tilapia lapsed into a coma in the latter part of the CO-treatment. CO level of the water sample increased steadily, the content of HbCO in the blood of tilapia stayed at the same level and the MbCO in the muscle of tilapia increased, but at a low rate. In general, tilapia’s respiration run through the transmission of CO in the whole process.2. The changes of physiological and fillet’s colour during tilapia euthanasia:In the CO-treatment, quality of the tilapia products under the influence of carbon monoxide was analyzed on the basis of behavioural analysis of tilapia,ECG analysis of tilapia,and Colour analysis of tilapia fillet. Tilapia leaded to strong stress response after contacted with carbon monoxide, such increased swimming activity, rapid ventilation of operculum and more restlessness, and a fast heartbeat, disorder ECG also indirectly reflected this response.In the late stage of CO-treatment, tilapia in the pool was almost stunned by carbon monoxide, but still had heartbeat, this could provided the follow-up blooding process with sufficient time. And obvious increase of tilapia fillet’s a*value and C*value after CO-treatment revealed that improvement of tilapia fillet’s color by CO-treatment was very remarkable. Therefore,carbon monoxide can endue tilapia fillet with bright redness, which greatly improved the quality of the fish products. 3.Study on the soak treating of tilapia fillet by carbon monoxide solution:Research on the effects of tilapia fillets in different carbon monoxide solutions was finished, by controlling the concentration of ammonia water, soaking temperature and soaking time, in order to determine optimal condition of the soak treating by carbon monoxide solution. The results showed that: Soaked tilapia fillet in carbon monoxide could also improve its color.The optimal condition was that controlling the ammonia concentration of3.5%,soaking temperature of0℃and soaking time of20min,and could obtain the satisfactory product of tilapia fillet.According to compare euthanasia,controlled atmosphere, immersion on the influence of tilapia fillets,using CO euthanasia makes tilapia fillets with the lowest carbon monoxide content in the aspect of quality, and have satisfactory effects of color and layers in the aspect of colour.Meanwhile,the process also makes tilapia fillets avoid secondary contamination to ensure the fresh quality.Conclusively,tilapia euthanasia is better than the other two.