Tilapia, which has the advantages of good resistance against the environment and disease, rapid growth, and being suitable for high-density cultivation, is one of the most common and important farmed fish species in the world and Taiwan. Moreover, as both its meat and scales can be used, it has high added value. The Fisheries Research Institute of COA has successfully developed a formula feed that can improve the hypothermia tolerance of tilapia, which increases its survival rate in low temperature environments by more than twice, and reduces the losses to aquaculture fishermen caused by cold-snap damage. Moreover, whole-fish utilization technology has also been fully developed and promoted in the industry.
Taiwan is in the subtropical zone. In winter, when the temperature drops to 10℃ or below due to intense continental cold air masses or cold waves, the Central Weather Bureau will issue low temperature special reports. During this time, the temperature will be lower in open areas outside the city and along the coast, which may easily induce a large number of farmed fish to experience frostbite and even freeze to death. To solve this issue, in addition to improving aquaculture management strategies, the Fisheries Research Institute has attempted to strengthen the tolerance of tilapia to low temperatures by adjusting feed nutrition. The formula feed developed in this study was supplemented with vitamins and suitable oils to enhance tilapia’s environmental resistance. After eight weeks of feeding, the experimental test at low temperatures (9-10℃ for six hours) showed that the survival rate of tilapia was increased by over two times.
According to the Fisheries Research Institute, in addition to being an important component of fish cell membranes, fat is the most energetic nutrient element, which can economize protein and improve the feed protein utilization rate. This kind of feed both enhances the cold resistance of tilapia and increases the content of polyunsaturated fatty acids in the tilapia flesh, hence increasing the nutritional value of tilapia products.
The Fisheries Research Institute emphasizes that in the future, it will focus more on continuous research on the diversity of fat and oil sources, as well as the effectiveness of feeding schedules. It will also strengthen the nutritional foundation for and breeding management of the overall winter cold tolerance of tilapia, thus, avoiding losses caused by cold-snap damage and ensuring the benefits of fishermen.
Figure. Feeding Tilapia with Cold Resistant Formula Feed Improved Low Temperature Tolerance of Tilapia. The Control Group on the Left and the Experimental Group on the Right.