Study On Feed Performance Of Tongue Sole(Cynoglossus Semilaevis Gunther) And Southern Flounder(Paralichthys Lethostigma)

The production performance of two feeds of Tongue Sole(Cynoglossus semilaevis Gunther)and Southern Flounder(Paralichthys Lethostigma) were assessed in this paper. Using the hard-pellet feed(43.46%protein) produced by Chilean company in control, the feeding rate, growth rate, feed conversion,quality of body shape, bio-chemical composition of the body and immune capacity etc.of juvenile Tongue Sole were determined and the economic and social benefits were analyzed brought by culture, as feeding power-form feed with low protein content(38.37%). Using frozen fresh fish as control, the effect to biological-evaluation indicators, quality of body shape and digestive morphology, the economic and social benefits were evaluated as feeding power-form feed. The main results were as follows:1. The specific growth rate of test group was significantly higher than control group and was 1.54 times for control group. The feeding rate of test group was 57% lower than that of the control group.2. There were significant effects to the feed conversion, feed conversion efficiency and protein efficient rate in different feeds. The feed conversion of test group was about one-fifth of control group, feed conversion rate and protein efficiency rate were 2.69 times and 3.01 times for control group.3. There were no significant differences in full-length, body thickness and fatness of Tongue Sole between two groups except body-length. The nutritional composition of the feeds didn't cause significant impact to the body moisture, protein and ash content of Tongue Sole, the fat content of control group was significantly higher than the test group.4. The phagocytic activity of leukocytes and serum lysozyme activity of control group were lower than test group but not significantly.5. The feed cost was reduced by 8.87 yuan using test feed than control feed when producing 500g Tongue Sole, it also reduced the pressure of culture environment .6. The feeding rate and feed conversion of Southern Flounder in the test group were significantly lower in average by 45% and 79% respectively than control group, the specific growth rate and weight gain in the test group were significantly higher in average by 87% and 68.5% respectively than control group.7. The body thick, height and fatness of Southern Flounder in test group were significantly higher than control group except full-length at the end of the first phase.At the end of second stage, above indicators of the Southern Flounder in two groups were no significant differences but the test group slightly higher.8. The length of digestive tract, thickness of stomach wall, intestinal length and thickness of Southern Flounder in test group were significantly higher than control group, offal situation was better than control group.9. Producing 500g Southern Flounder the test group could save five yuan compared with the control group, reducing the use of fresh raw fish was conducive to the protection of the environment.Based on the above findings and combined with other studies, we can get conclusions below:1. The feed with 38.37% protein level can meet the growing need of juvenile Tongue Sole, promote growth and weight gain effectively, lower feed conversion and maintain a high level of protein and feed utilization. 43.46% protein level would reduce the growth effects and protein efficiency.2. The fatness and body nutritional composition are close between two groups of juvenile Tongue Sole, the test group is longer and thiner, the control group is thicker. These are attributed to the nutrient composition and content of the feeds.3. From the perspective of nutritional immunology, the test group has higher level of immune ability. It shows the balance of vitamin and nutritional additives may be superior in test feed to the control feed.4. The feed cost of the test feed is far lower and the negative impact on the environment is also less than control group. From the dual perspective of economic and social benefits, the test feed is more suitable for the breeding of Tongue Sole.5. Compared with fresh fish, the test diet can significantly increase the growth rate of juvenile Southern Flounder, shorten the breeding cycle, lower feed conversion and reduce the cost of cultivation.6. The close of the shape indexes indicates the nutritional value of the two diets is consistent. The shape of the Southern Flounder in test groups can achieve the same level of culturing with fresh fish.7. The juvenile Southern Flounder can adapted to the feed through changing the initiative shape of digestive tract, it is beneficial for the absorption and utilization of nutrients.8. Using the test feed to breed juvenile Southern Flounder can save feed costs effectively, reduce nitrogen and phosphorus pollution to the environment and protect marine fisheries resources. It is conducive to the sustainable development of aquaculture industry.