Effects Of Exogenous Nitric Oxide On Tilapia

Based on the research of the treatments of tilapia with the exogenous NO (nitric oxide) and it’s process optimization, the tilapias were anesthetized with saturated NO solution when slaughtered, and the tilapia fillets were treated with NO solution and NO gas. This article has studied the effect of the exogenous NO on animal welfare of tilapia and the quality of tilapia fillets, such as the color, rigor index, pH, drop loss and TVB-N values.When were anesthetized with saturated NO solution, tilapias were surgically anesthetized after20min treatment and performed peacefully during the process. At5min, the swimming activity reduced. At10min, equilibrium loss with efforts to right. At15min, tilapias reached deep narcosis. And at20min, tilapias were surgically anesthetized.Both the red and white muscle of the three kinds of tilapia fillets, the fillets from the saturated NO solution anesthetized tilapia, the NO solution treated tilapia fillets and the NO gas treated tilapia fillets, had a brighter red color than those of the control, and had a significant increase in redness (a*values). The a*values of the red muscle of the three tilapia fillets increased from2.25to4.48,8.15,4.05, respectively, and the white muscle from-4.27to-3.78,-1.93,-2.99, respectively. During the15d storage, these a*values all kept in stability. Treatment with the exogenous NO leaded to a higher tenderness of the fillets and prolonged the pre-rigor period. The pre-rigor period of the three tilapia fillets had been prolonged for7h,2h,2h, and the maximum rigor index had been reduced for5%,33%,33%, respectively. After the exogenous NO treatment, pHs of the three tilapia fillets had reduced, while drop loss increased. Moreover, tilapia fillets with the exogenous NO treatment had no negative effect on the TVB-N values. The final pHs of the three tilapia fillets are5.85,6.82and6.80. Drop loss of the NO solution treated and NO gas treated tilapia were higher than the control. And the three TVB-N values were as similar with the control, all near the20mg/100g at day15. The results suggested that treatment with the exogenous NO could be an effective method to improve the animal welfare of tilapias and quality of tilapia fillets.