Growth and Feeding Responses of Male versus Female Yellow Perch (Perca flavescens) Treated with Estradiol-17β

Abstract

In yellow perch (Perca flavescens) (initially 13–16 g total weight) fed to satiation (3.0–3.5% of body weight per day), estradiol-17β (E2) at 15 μg/g diet stimulated weight gain and food consumption of both sexes but did not influence food conversion efficiency (FCE), as measured by weight gain of fish per weight of food consumed. Females fed to satiation gained more weight, consumed more food, and had higher FCE than males. In perch fed a restricted ration (1.2% of body weight per day), the differences between the sexes in weight gain were reduced and due entirely to differences in FCE, and weight gain was not improved by E2. Spatial segregation or integration of the sexes had no influence on sex-related growth patterns in perch fed either the satiation or restricted ration. Carcass composition of perch treated for 84 d with E2 at 2, 20, or 50 μg/g diet did not differ from that of controls. These data indicate that (1) estrogens promote growth in yellow perch by stimulating food consumption, (2) female perch outgrow males because of both greater food consumption and higher FCE, and (3) growth differences between the sexes are not a consequence of intersexual competition for food.

Cannibalism in cultured Eurasian perch, Perca fluviatilis (Actinopterygii: Perciformes: Percidae)—Implication of maternal influence, kinship, and sex ratio of progenies

“…The absence of significant sexrelated effect on the growth of Eurasian perch is in agreement with previous studies on the American yellow perch (Malison et al 1988) and the Eurasian perch (Babiak et al 2004). Stejskal et al (2009) found that the significance differences in body weight between all-female and mixedsex stocks of perch began at age 144 days, when fish were over 13 g. The sexual growth dimorphism in perch probably appears markedly when sexual maturation reduces somatic growth.…”

Neither male gonadal androgens nor female reproductive costs drive development of sexual size dimorphism in lizards

“…Effects on growth of female gonadal hormones have rarely been tested in squamate reptiles (but see Lerner and Mason, 2001) [for evidence in other vertebrates, see Malison et al (Malison et al, 1988) or Govoni et al (Govoni et al, 2008)], which precludes evaluating whether estrogens or progestins may affect female growth in the opposite direction in female-versus male-larger lizard species [see Cutler (Cutler, 1997) for support for the role of low levels of estrogens in regulation of growth in humans]. Testing this hypothesis will require further experimental work focused specifically on hormonal manipulations in females of male-larger and female-larger species.…”

Modeling sources of variation for growth and predatory demand of Lake Erie walleye (<I>Stizostedion vitreum</I>), 1986-1995

“…Factors influencing sexual dimorphism have been investigated for a closely related percid, yellow perch, in which estrogenic compounds stimulate female growth, whereas androgenic compounds retard male growth rates (Malison et al 1985(Malison et al , 1988. For both sexes, these changes in growth rate were related to maturation.…”