engleski

Growth and body composition of common carp (Cyprinus carpio L.) maintained under aphagic thermal conditions: response to porcine somatotropin therapy

In carp (Cyprinus carpio), the preferred optimal temperatures for growth lie between 30 and 32oC and a variety of studies have determined that growth in this species is retard with decreasing temperature until, at <10oC, aphagia ensues. Under such "aphagic thermal conditions" carp may lose weight, even though provided with feed adequate enough to support growth. Several authors have suggested a positive correlation between growth hormone (GH) secretion and temperature. Thus, the loss of appetite in carp maintained at suboptimal temperatures may due to reduced activity and/or synthesis of endogenous GH. By deduction, replacement therapy of carp with an exogenous source of GH might stimulate appetite and growth during winter temperatures. Accordingly , the present study was undertaken to determine whether exogenous porcine (p) GH therapy could maintain or accelerate growth of carp held at temperatures bordering on their aphagic thermal position (11.9+-0.9oC). Carp (n=20/group) were treated with saline (0.9%) or pGH at doses of 1, 2 or 4 ug/g/wk. Treatments wre given by intraperitoneal injection. Observations were made over an 8-week period. All fish showed positive growth throughout the study. Relative to other treatment groups, only carp injected with 4 ug pGH/g/wk showed significant (P<0.05) growth acceleration. All fish injected with pGH showed significantly (P<0.05) reduced body lipid levels when compared with saline-injected carp.

carp ; growth ; porcine somatotropin ; therapy

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