Effects of two kinds of dissolved copper on growth and immune function of Litopenaeus vannamei

Abstract:

Litopenaeus vannamei was used as main experiment object. Chronic enrichment was used to determine the effect of copper in different concentrations or dissolved forms during 56 days on immune active substances in Litopenaeus vannamei. The experiments were divided into five groups:one control group without Cu addition, two groups of different dosage of complexing Cu group and Cu addition group with which matched the complex Cu group released Cu. The LC6911 type corrosion-resistant alloy Cu was used as a complex Cu source, using 0.15 m² copper plate/m³ and 0.3 m² copper plate/m³ respectively, and the other two groups added matched amount CuSO₄·5H₂O as Cu²⁺ source. The following conclusions were drawn:(1) In the water of non-cultured, the experiments used LC6911 type corrosion-resistant alloy Cu tiled with 2 m³ aquarium barrel bottom. The total Cu released by copper plate was directly proportional to those area. (2) Immune proteins CP, POX,MT activities improved under two concentration gradients in experimental group, which was significantly higher than control group (P<0.05). (3) The enzyme activity of LZM in shrimp hemolymph was found in the experimental group of two different dissolved states. The results showed significant differences among control group and others at the end of the experiment (P<0.05). There was no significant difference between the two types of dissolved Cu and the different additive levels. And there was no significant difference in the LZM activity between the experimental group and the control group in gill tissue either (P>0.05). But the activity of LZM in Cu²⁺ group decreased significantly (P<0.05).(4)The long-term growth data showed that the growth effect of the experimental groups was not significantly better than that of control group, and the growth effect of the 0.15 m²Cu-plate/M3 group was the best. The enhancement of the immune activity and growth of Litopenaeus vannamei by complexing Cu in water is more prominent than Cu²⁺, meanwhile, using 0.3 m² copper plate/m³ in seawater has lower long-term toxicity effects on Litopenaeus vannamei's immune system.