Open AccessEffects of dietary cortisol administration on sex ratios in dwarf gouramis and rosy barbs
Author(s) -
Ramee Shane W.,
Lipscomb Taylor N.,
DiMaggio Matthew A.
Publication year - 2020
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/jwas.12720
Subject(s) - biology , endocrinology , sexual differentiation , medicine , development of the gonads , corticosterone , aquaculture , sex reversal , genotype , hormone , genetics , gene , gonad , fish <actinopterygii> , fishery
Sexual differentiation in teleosts is based on diverse and complex combinations of genetic and environmental factors. Environmental conditions during early development can alter gonadal differentiation leading to sex reversal, where the individual's genotypic and phenotypic sexes are opposite. In many species, the mechanism of environmental sex reversal has been linked to the stress axis and fluctuations in cortisol. This mechanism could be utilized to manipulate sex ratios in ornamental aquaculture, where the males of sexually dichromic species are often more economically valuable due to their brighter coloration. Dietary cortisol administration was used as a proxy for environmental stress to evaluate the effects on gonadal differentiation in two ornamental species, rosy barb, Pethia conchonius and dwarf gourami, Trichogaster lalius . Three experiments were run with each species to assess the following: (a) postprandial cortisol levels following dietary administration, (b) the effect of dietary cortisol concentration on sex ratios, and (c) the effect of developmental timing of cortisol feed administration on sex ratios. Whole‐body cortisol enzyme‐linked immunosorbent assays confirmed that cortisol feed did cause increased cortisol levels. However, despite cortisol feed being administered during the putative gonadal differentiation period, no effect was observed in the final sex ratios for any of the treatments evaluated.