Feed Nutrition Requirements for Rainbow Trout Fry and Fingerling Farming

Based on the nutritional needs of rainbow trout as well as the raw material supply and cost conditions in developing countries, the United Nations Development Programme and the Food and Agriculture Organization proposed the following rainbow trout nutrition recommendations: the minimum protein requirement for rainbow trout fry and fingerlings is 36%; the calcium requirement is 1.0%-1.5%; the available phosphorus requirement is 0.5%-0.8%; the minimum lysine requirement is 2.0%; the minimum methionine and cystine requirement is 1.2%; the minimum digestible energy requirement is 1506.24 kJ/100 g; the minimum vitamin A requirement is 600,000 IU; the minimum vitamin D requirement is 100,000 IU; the minimum vitamin E requirement is 6,000 IU; the minimum vitamin K requirement is 1.2 g; the minimum vitamin C requirement is 24.0 g; the minimum vitamin B1 requirement is 2.4 g; the minimum vitamin B2 requirement is 2.4 g; the minimum pantothenic acid requirement is 6.0 g; the minimum niacin requirement is 12.0 g; the minimum vitamin B6 requirement is 2.4 g; the minimum biotin requirement is 0.024 g; the minimum folic acid requirement is 0.6 g; the minimum choline chloride requirement is 54.0 g; the minimum vitamin B12 requirement is 2.4 g; the mineral iron requirement is 5.0 g/100 kg; the mineral zinc requirement is 3.0 g/100 kg; the mineral manganese requirement is 2.0 g/100 kg; the mineral phosphorus requirement is 10.0 mg/100 kg; the mineral cobalt requirement is 1.0 mg/100 kg; the mineral selenium requirement is 10.0 mg/100 kg.

After the feed ingredients are mixed according to the nutritional requirements, they are processed into pellets with a diameter of 4-8 mm for feeding. When the water temperature is above 3°C, feeding must be carried out every day. At suitable temperatures, feed two to three times a day, with a daily feeding amount of 1%-3% of the fish body weight. It is best to feed until they are about 80% full. Overfeeding will cause poor growth in rainbow trout and may even lead to the occurrence of disease.