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Effects of stocking density on growth and non‐specific immune responses in juvenile soft‐shelled turtle, Pelodiscus sinensis
Author(s) -
Chen Xinran,
Niu Cuijuan,
Pu Lijun
Publication year - 2007
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2007.01813.x
Subject(s) - biology , stocking , immune system , juvenile , turtle (robot) , zoology , immunity , immunology , fishery , ecology
To investigate the influence of stocking density on the growth and non‐specific immune responses of juvenile soft‐shelled turtle, Pelodiscus sinensis , three groups of turtles (initial body weight 74.2±12.2 g) were reared in 80 cm (L) × 40 cm (W) × 30 cm (H) tanks for 35 days at three stocking densities (StD), which were 1 individuals (ind.) tank −1 (3.13 ind m −2 ) for D1, 4 ind. tank −1 (12.5 ind m −2 ) for D2 and 6 ind. tank −1 (18.75 ind m −2 ) for D3 respectively. D1 was the control group. Turtles were weighted individually at the beginning and at the end of the trial. At the end of the rearing trial, non‐specific immune parameters were determined. The results showed that the heterophil:lymphocyte ratio (HLR) increased and the total plasma protein decreased with increasing StD, suggesting a stress response. Specific growth rate (SGR) significantly decreased with increasing StD. Non‐specific immune indicators such as blood cell phagocytic activity, serum haemolytic activity and serum bacteriolytic activity increased clearly at a higher StD, indicating a pattern of immunoenhancement. The results indicated that at StDs of 4 and 6 ind. tank −1 , non‐specific immune responses were not suppressed compared with the control, but were inversely enhanced at the cost of growth reduction. A possible energy‐based trade‐off between growth and constitutive immunity may exist in soft‐shelled turtles.