Abstract:

In order to explore the effects of breeding space sizes on the growth, nutrition, and immunity of Procambarus clarkii, and provide theoretical guidance for the development of industrial aquaculture of P. clarkii, an experiment of P. clarkii cultivation was conducted in an indoor circulating water aquaculture system. Four types of individual breeding spaces were set up in this experiment, including sizes of 15 cm×15 cm, 15 cm×20 cm, 15 cm×25 cm and 15 cm×30 cm (referred to as S₁, S₂, S₃ and S₄ group), respectively. The experiment lasted for 56 days. In terms of growth performance, the final body weight (20.57 g), weight gain rate (305.18%), and specific growth rate (2.56%/d) of the S₁ group were significantly lower than those of the other groups (P<0.05), and the abdominal meat rate of the S₁ group (12.13%) was significantly higher than that of the S₃ group (P<0.05), and there was no significant difference in the survival rate among all groups. In terms of nutritional performance, with the increase of breeding space, the muscle water content in each group showed a trend of first increasing and then decreasing, reaching the highest level of 79.54% in group S₂. The crude ash content showed a gradually increasing trend, with the S₄ group having the highest content at 9.37%. There was no significant change in crude protein and crude fat content. The amylase activity in the intestines of each group showed an overall decreasing trend, with the S₂ group having the highest activity at 31.34 U/(g·prot) and the S₄ group having the lowest activity at 21.91 U/(g·prot). The lipase showed a trend of first decreasing and then increasing, with the S1 group having the highest value at 8.51 U/(g·prot) and the S₃ group having the lowest value at 4.96 U/(g·prot). Trypsin showed an increasing trend, with the S₄ group being the highest at 220.53 U/(g·prot) and the S₁ group being the lowest at 23.97 U/(g·prot). In terms of immune indicators, with the increase of breeding space, the activity of superoxide dismutase, acid phosphatase and alkaline phosphatase in the hemolymph of each group showed a trend of first increasing and then decreasing. Among them, the activities of superoxide dismutase and alkaline phosphatase were the highest in the S₂ group, at 31.34 and 362.10 U/(g·prot), respectively. The activity of acid phosphatase was the highest in the S₃ group, at 96.72 U/(g·prot). The content of malondialdehyde showed a trend of first decreasing and then increasing, with the lowest level in the S₃ group at 2.83 nmol/(g·prot). In summary, under the monoculture mode, the size of the breeding space will have an impact on the growth and physiological and biochemical status of P. clarkii. Overall, when the single breeding space is set at a size of 15 cm×20 cm to 15 cm×25 cm, P. clarkii can exhibit good growth, nutrition, and immune performance.

Key words: Procambarus clarkii, breeding space, growth, nutrition, immunity