Water, seed and bait are the basic conditions for fishery production. In order to obtain better breeding results and reduce the cost of fish farming, attention should be paid to the following issues when feeding: The shape, structure, and specifications of the feed are important for the fish to receive or reject certain foods. The size of feed pellets not only affects palatability, but also affects digestibility. Therefore, the size of the pellet feed should be selected to be suitable for fish swallowing at each growth stage. Fish is large and the feed is too small. Fish do not easily feed and sink to the bottom of the pond. On the contrary, the feed pellets fed by small fishes are very large, which is not conducive to fish swallowing and losing water. This kind of feed has a low utilization rate. Rainbow trout feed, fry of 12 grams or less, according to their individual size can be selected 0.3 ~ 2.2 mm pellet feed; 12 ~ 60 g of fish can be selected from 2.2 to 3.2 mm tablets The granules with a diameter and length of 3. 4 mm are fed; individual individuals between 60 and 195 g can choose 3.5 to 4.5 mm in diameter and 4 to 5 mm in length for feeding; individuals above 195 g are bred. Particle size 5 mm, length 6 to 8 mm pellets. 2. The level of dissolved oxygen in water has a great influence on the fish's food intake, digestion and absorption after food intake and fish growth. The dissolved oxygen in the water is low, the appetite of the fish is poor, and the digestion and absorption rate of the feed after eating is low, the growth rate is slow, and the feed coefficient is high. When rainbow trout exceeds 9 mg/L of dissolved oxygen, metabolism is strong, growth is good, and feed utilization rate is high. Below 5 mg/l, respiratory rate increases. Below 4.3 mg/L, floating heads appear and no food is consumed. Therefore, when feeding, attention should be paid to changes in dissolved oxygen in the water. The dissolved oxygen in the water is low, the fish floats, and do not feed. Dissolve oxygen in the water before feeding. In rainbow trout feeding, hypoxia generally occurs in the rear fishpond in series, and the stocking density of the rear fish pond should be noted. It should be smaller than the density of the fish pond in front. In addition, sewage should be discharged in time to maintain good water quality. 3. Pay attention to changes in water temperature. Rainbow trout living water temperature 0-25 °C, optimal growth D water temperature 16 ~ 18 °C, below 8 °C or above 20 °C, loss of appetite, slow growth D slow, more than 24 °C to stop feeding. In the actual production, the conditional Party D, the temperature of the well pumping water in the high temperature season, the temperature of the hot spring water in winter, and the temperature D of the pool water are maintained at 16 to 18°C, which can greatly increase the growth rate of the rainbow trout and the utilization rate of the feed. 4. Intraspecific activities limit the feeding of rainbow trout. The adverse effects of specifications and invasiveness on feeding are common in rainbow trout farms. The aggressive fish in the cultured population (a D is a big fish) will affect the appetite or food intake of the fish, thereby affecting its growth. Only when the big fish are full, they can only eat. Increasing the number of feedings or evenly spreading the feed r helps feed the small fish. In addition, rainbow trout species have uneven growth and are screened once a month. Different specifications are selected and fed separately to facilitate their growth and improve feed utilization. 5. The amount of daily feeding should be appropriate. When the feeding amount is too low, the fish is in a state of semi-starvation, and the growth is slow. When the amount of feed is too high, not only the feed utilization rate is low, but also the water quality is deteriorated and diseases are caused. The appropriate feed rate is the guarantee of the fastest growth rate of fish and the highest feed conversion efficiency. The daily feeding amount was expressed as feeding rate, ie, the dry weight of the feed was calculated as the percentage (%) of the weight of the fed fish. Different feed quality, different stages of fish growth, different water temperatures, feeding rates are different. When the protein content of rainbow trout juvenile granules is 45%, feed at a water temperature of 14°C with 3.7%, and feed at 4.3% at 16°C; when the protein content of granules is 40%, 14°C When feeding was calculated at 1.8%, it was fed at 2.1% at 16°C to meet the nutritional requirements for normal growth of rainbow trout. In rainbow trout farming, its weight will increase, and according to the weight gain situation, the amount of feed will be adjusted timely. The fish breeding stage carries out 3 measurements per month and adjusts the amount of feeding 3 times; the adult fish stage adjusts the feeding amount every 15 days. 6. Feeding should be timed and the number of feedings should be appropriate. Regular feeding will enable the fish to maintain a certain number of satiety daily, and their growth, assimilation efficiency and feed conversion rate will remain at a high level. Too many feedings cause incomplete digestion and reduce feed utilization. When the number of feedings is too small, the amount of each feeding is inevitably large and the feed loss is severe. Higher feed nutritional value may be less appropriate, and lower nutritional value may be more appropriate. When the water temperature and dissolved oxygen are high, it may be more appropriate, but otherwise it may be less or stop feeding. Rainbow trout fry stage feeding 4 to 3 times, 3 to 2 fish stage, adult and broodstock 2 times. Feeding twice a day, preferably in the morning 9 to 10 o'clock in the afternoon, 16 to 17 o'clock; did not feed three times a day, in the morning 8 to 9 o'clock, 12 to 13 o'clock noon, 17 to 18 o'clock in the afternoon; day feeding 4 Secondly, 4 feedings can be evenly set between 8 and 18 hours. 7. When feeding, pay attention to feeding speed, be patient and careful, pay attention to methods. When feeding, every time you cast a word, you should feed the feed into the water bit by bit with a certain frequency, and do not put the feed into the water at one time. This will cause feed loss. The research on rainbow trout found that the food intake was large at the beginning of feeding, and then quickly decreased to a halt. Therefore, the duration of each feeding of rainbow trout should not be too long or too short, too long feeds will sink into the bottom of the water, and the feed utilization rate is low; for most fishes, it is not yet up to 80% full. The duration of each feeding of rainbow trout should be 15 to 20 minutes. Deteriorated feed should not be fed.
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