Influence of oral administration of estradiol-17? and testosterone on growth, digestion, food conversion and metabolism in the underyearling red sea bream, Chrysophrys major

Woo, Norman Y.S.; Chung, A.; Ng, Tzi Bun

doi:10.1007/bf00004504

Cited by 44 publications

(14 citation statements)

References 60 publications

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“…Some authors such as Woo et al (1993) and Ahmad et al (2002) supported the present results. The increase in body weight gain may be attributed to that androgen steroids enhance the release of growth hormone from the pituitary somatotrophs of fish and/or induce the feed digestion and absorption rate, causing increase in body weight (Khalil et al, 2011).…”

Section: -Percentage Of Sex Reversed Fishsupporting

confidence: 89%

Comparative study for the production of the male Nile tilapia between inter-specific hybridization and hormonal sex reversal

Al-Hakim

Hessen

Rizkalla³

et al. 2013

Egypt. J. of Aquatic Biolo. and Fish.

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ABSRRACTTilapia fry were produced by hybridization of males of blue tilapia (Oreochromis aureus) with females of Nile tilapia (O. niloticus) and by sex reversal using oral administration of 3 doses (60, 80 and 100 mg/kg diet) of the androgen 17 α-methyltestosterone (MT) for 28 days. Fry were fattening in earthen ponds for 210 days.All treatment groups that received androgen MT (T 3 , T 4 and T 5 ) showed sex reversal with a significantly higher males proportion than females as compared to the control (T 2 ) and hybrid (T 1 ) groups. The treatment group that received 60 mg MT (T 3 ) exhibited the best growth performance parameters (average weight gain, average daily gain and specific growth rate) and feed utilization parameters (feed conversion ratio, protein efficiency ratio, protein production value and energy utilization). The highest percentage of body crude protein; ether extract and ash were detected in T 3 group. With regard to human food safety, tilapias that treated with MT (T 3 , T 4 and T 5 ) rapidly excrete ingested hormone and MT levels falling to lower concentrations than that in both hybrid (T 1 ) and control (T 2 ) groups.

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Section: -Percentage Of Sex Reversed Fishsupporting

confidence: 89%

Comparative study for the production of the male Nile tilapia between inter-specific hybridization and hormonal sex reversal

Al-Hakim

Hessen

Rizkalla³

et al. 2013

Egypt. J. of Aquatic Biolo. and Fish.

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“…carotenoids (Blas et al, 2006), possibly through direct effects of testosterone on lipoproteins or digestive enzymes, which regulate carotenoid availability (e.g. Woo et al, 1993;McGraw et al, 2006). Unfortunately, we did not measure circulating testosterone levels in the blood.…”

Section: Effects Of Egg Treatmentmentioning

confidence: 99%

Sex-specific effects of prenatal testosterone on nestling plasma antioxidant capacity in the zebra finch

Tobler

Sandell

2009

Journal of Experimental Biology

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SUMMARYTrans-generational transfer of non-genetic, maternal resources such as hormones can have a substantial influence on offspring phenotype in many vertebrate species. In birds, maternal androgens enhance both growth and competitive behaviour, but also suppress the immune system. It has been hypothesised that high levels of egg androgens could also influence the prooxidant-antioxidant balance through their positive effect on growth and metabolism. We tested this hypothesis in the zebra finch (Taeniopygia guttata). Eggs were injected with testosterone dissolved in sesame oil or sesame oil only (control). We subsequently assessed the effect of the egg hormone manipulation on nestling growth and nestling plasma total antioxidant capacity (TAC). Growth rates of zebra finch nestlings were not significantly affected by egg hormone treatment. However, male offspring hatched from eggs with experimentally elevated testosterone had reduced plasma TAC at 10 days of age compared with male offspring hatching from control eggs. At the age of 34 days, males had similar plasma TAC irrespective of egg treatment. No effects of egg testosterone manipulation on nestling plasma TAC were found in females. Our results demonstrate that embryonic exposure to elevated levels of testosterone modulates chick antioxidant status, but this seems to be independent of chick growth. Sex-specific effects of prenatal testosterone on plasma TAC of zebra finch nestlings may have important consequences for sex allocation.

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“…With regard to the hypothesis that testosterone increases the absorption efficiency of ingested carotenoids, we did not find any difference between treatments in the length of the digestive tract (Table 3), a trait showing considerable phenotypic plasticity in galliforms (39). Carotenoid absorption, however, could also be enhanced through increases in plasma lipoproteins or changes in the activity of digestive enzymes, all of which are affected by testosterone (40)(41)(42).…”

Section: H13mentioning

confidence: 99%

Testosterone increases bioavailability of carotenoids: Insights into the honesty of sexual signaling

Blas

Pérez‐Rodríguez

Bortolotti

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

194

159

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Androgens and carotenoids play a fundamental role in the expression of secondary sex traits in animals that communicate information on individual quality. In birds, androgens regulate song, aggression, and a variety of sexual ornaments and displays, whereas carotenoids are responsible for the red, yellow, and orange colors of the integument. Parallel, but independent, research lines suggest that the evolutionary stability of each signaling system stems from tradeoffs with immune function: androgens can be immunosuppressive, and carotenoids diverted to coloration prevent their use as immunostimulants. Despite strong similarities in the patterns of sex, age and seasonal variation, social function, and proximate control, there has been little success at integrating potential links between the two signaling systems. These parallel patterns led us to hypothesize that testosterone increases the bioavailability of circulating carotenoids. To test this hypothesis, we manipulated testosterone levels of red-legged partridges Alectoris rufa while monitoring carotenoids, color, and immune function. Testosterone treatment increased the concentration of carotenoids in plasma and liver by >20%. Plasma carotenoids were in turn responsible for individual differences in coloration and immune response. Our results provide experimental evidence for a link between testosterone levels and immunoenhancing carotenoids that (i) reconciles conflicting evidence for the immunosuppressive nature of androgens, (ii) provides physiological grounds for a connection between two of the main signaling systems in animals, (iii) explains how these signaling systems can be evolutionary stable and honest, and (iv) may explain the high prevalence of sexual dimorphism in carotenoid-based coloration in animals.honest signaling ͉ immune function ͉ immunocompetence handicap hypothesis ͉ coloration P arallel, but independent, lines of research indicate that both androgens and carotenoids play a major role in the development and expression of honest signals of individual quality among vertebrates, relevant in sexual and social contexts (1-14). In birds, androgens control song, aggression, and a variety of sexual ornaments and displays (1-4), and carotenoids are bright red and yellow pigments of showy integument (6-12). In addition to signaling functions, testosterone regulates male sexual maturation and sperm production (15), and carotenoids have antioxidant and immunoenhancing activity (8,9,12,16,17). Signaling theory posits that the stability of traits conveying information on individual quality relies on the costs associated with signal production (18, 19), which prevent cheating in poor-quality individuals (they are ''honest'' signals) (19). Following this reasoning, the immunocompetence handicap hypothesis (ICHH) (20) posits that the honesty of androgen-dependent sexual traits relies on the immunosuppressive action of testosterone (21,22). Recent studies emphasize that carotenoid allocation to color displays imply diversion away from the immune and deto...

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Influence of oral administration of estradiol-17? and testosterone on growth, digestion, food conversion and metabolism in the underyearling red sea bream, Chrysophrys major

Cited by 44 publications

References 60 publications

Comparative study for the production of the male Nile tilapia between inter-specific hybridization and hormonal sex reversal

Comparative study for the production of the male Nile tilapia between inter-specific hybridization and hormonal sex reversal

Sex-specific effects of prenatal testosterone on nestling plasma antioxidant capacity in the zebra finch

Testosterone increases bioavailability of carotenoids: Insights into the honesty of sexual signaling

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