M. A. Nematollahi - Department of Fisheries, Faculty Natural Resources, University of Tehran, Chamran St., P. O. Box: ‎‎۳۱۵۸۵-۴۳۱۴, Karaj, Islamic Republic of Iran.‎
H. de Van Pelt - Animal Breeding and Genomics Center, Wageningen Institute of Animal Sciences (WIAS), Wageningen ‎University, PO Box: ۳۳۸, ۶۷۰۰ AH Wageningen, The Netherlands.‎
H. Komen - Animal Breeding and Genomics Center, Wageningen Institute of Animal Sciences (WIAS), Wageningen ‎University, PO Box: ۳۳۸, ۶۷۰۰ AH Wageningen, The Netherlands.‎

The aim of this study was to analyze the stress response during ۳ hours net confinement stress and recovery period of ۲۲ hours in normal (STD) and in ۱۷α-hydroxylase deficient common carp (E۵). Fish were raised for ۶ months and sampled at T۰ (control, unstressed), ۵ minutes, ۲۰ minutes, ۱ hour and ۳ hours of exposure to net confinement, and after ۱ hour, ۴ hours, and ۲۲ hours of recovery. At every sampling time, blood was collected to determine cortisol, corticosterone, glucose, lactate and free fatty acids (FFA) levels (۵ fish per strain). Fish and head kidney were weighed before and after dissection, respectively, to determine head kidney somatic Index (HKSI). Morphometric analysis of head kidney tissues indicated that the head kidney somatic index was significantly higher in E۵ fish (۰.۰۷۶±۰.۰۲۱) compared with STD fish (۰.۰۴۵±۰.۰۱۵). Also, significant differences in cortisol and corticosterone as well as in glucose, lactate and FFA values were observed between the two strains of E۵ and STD. Moreover, the pattern of changes of glucose and FFA during stress and afterward indicated a significant difference compared to the T۰. Results support the conclusion that the reduced capacity of ill fish to produce cortisol is caused by a deficiency in ۱۷α-hydroxylase activity. A reduced cortisol output leads to increased stimulation of adrenals by adrenocorticotropic Hormone (ACTH), resulting in increased outputs of corticosterone.

Congenital interrenal hyperplasia, Corticosterone, Cortisol. ‎