| For recent several decades, the industry of shrimp culture has been developing rapidly in the world. Litopenaeus vannamei, as one of the top three excellent breeds which has the top output in the world, has made dominant contribution. However, the increase of dimensions, and the bigger density of Litopenaeus vannamei culture has caused many problems, such as the burst of disease, environment pollution, low economic benefit. According to the reality of different areas, ecological polyculture system is used to reduce disease and increase benefit.Integrated Multi-Trophic Aquaculture, which means, fed organisms (fish), organisms that extract either dissolved inorganic nutrients (seaweeds) or particulate organic matter (shellfish) are cultured together according to theory of ecological balance. The diversity and stability of IMTA ecosystem are better than that of monoculture system in improving water environment and increasing economic benefit.Under the theory "Integrated Multi-Trophic Aquaculture "(IMTA), Litopenaeus vannamei’and other different trophic level species, such as fish, Hyriopsis cumingii, Ipomoea aquatica Forsk and so on were cultured together to study the effect in the experiment to provide references for the low carbon and efficient shrimp culture system. There are three experimental groups(A,B,C) and one control group(D)in the experiment, every group has three repeats which were done in12outside cemented ponds (16m2). Litopenaeus vannamei, Ipomoea aquatica Forsk, Hyriopsis cumingii and Ietalurus punetaus were cultured in group A. Misgurnus anguillicaudatus took the place of Ietalurus punetaus in group B and Oreochromis spp was the substitution in group C, the same as group A for the others. litopenaeus vannamei is the only species in group D. The experiment lasted80days. Water quality indexes were tested, including TAN, NO2--N, NO3--N, TN, TP, Chl-a, TSS, COD and shrimps were taken as samples to measure the length and weight regularly. Nutrition constituent,such as moisture, crude protein, crude fat and collagen were analyzed after the experiment.The result showed that the average concentration of TAN in group A,B,C has reduced3.2%,8.1%,0.8%(P>0.05)than that of control group D, which is1.17mg/L. The average concentration of nitrite in group A,B,C has reduced10.2%,12.6%,4.8%(P>0.05) than that of group D, which is0.157mg/L. In the later stage, the concentration of TAN in group A,B,C has reduced12.1%,11.8%,5.9%(P>0.05) than that of control group D, which is1.83mg/L. The average concentration of nitrite in group A,B,C has reduced8.9%,10.0%,3.3%(P>0.05) than that of group D, which is0.615mg/L.As to the growth rate and survival rate of shrimp, there was no significant difference in the medium stage (P>0.05). But in the later stage, the weight gain rate of group B increased50.42%compared to group D; and the survival rate of group B reached80.18%, which was higher than that of other groups. There was no significant difference in nutrition constituent of shrimp, which means, the IMTA polyculture can’t influence the quality of shrimp.The result showed that the polyculture is better in improving pond environment, in favor of the growth and increasing the survival rate of shrimp than shrimp monoculture system, which can get better results. Mixing Misgurnus anguillicaudatus is better for shrimp. |
