Sex inversion in domestic chicken (Gallus gallus domesticus) by letrozole and tamoxifen

Trukhina, A. V.; Лукина, Н. А.; Wackerov-Kouzova, N. D.; Nekrasova, A. A.; Smirnov, A. F.

doi:10.1134/s1990519x14030122

Cited by 8 publications

(7 citation statements)

References 30 publications

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“…Sex reversal was also obtained in the European pond turtle ( Emys orbicularis ) after their thermo-sensitive period by application of letrozole [ 73 ]. Sex inversion was also observed in G. gallus by application of letrozole and tamoxifen [ 74 ]. Deng and co-workers [ 75 ] showed that letrozole also inhibited the development of bone and medullary osteogenesis in prelay pullets by inhibiting the synthesis of oestrogen and its receptor.…”

Section: Resultsmentioning

confidence: 99%

Modelling inhibition of avian aromatase by azole pesticides

Saxena¹,

Devillers²,

Bhunia

et al. 2015

SAR and QSAR in Environmental Research

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The potential effects of pesticides and their metabolites on the endocrine system are of major concern to wildlife and human health. In this context, the azole pesticides have earned special attention due to their cytochrome P450 aromatase inhibition potential. Cytochrome P450 aromatase (CYP19) catalyses the conversion of androstenedione and testosterone into oestrone and oestradiol, respectively. Thus, aromatase modulates the oestrogenic balance essential not only for females, but also for male physiology, including gonadal function. Its inhibition affects reproductive organs, fertility and sexual behaviour in humans and wildlife species. Several studies have shown that azole pesticides are able to inhibit human and fish aromatases but the information on birds is lacking. Consequently, it appeared to be of interest to estimate the aromatase inhibition of azoles in three different avian species, namely Gallus gallus, Coturnix coturnix japonica and Taeniopygia guttata. In the absence of the crystal structure of the aromatase enzyme in these bird species, homology models for the individual avian species were constructed using the crystal structure of human aromatase (hAr) (pdb: 3EQM) that showed high sequence similarity for G. gallus (82.0%), T. guttata (81.9%) and C. japonica (81.2%). A homology model with Oncorhynchus mykiss (81.9%) was also designed for comparison purpose. The homology-modelled aromatase for each avian and fish species and crystal structure of human aromatase were selected for docking 46 structurally diverse azoles and related compounds. We showed that the docking behaviour of the chemicals on the different aromatases was broadly the same. We also demonstrated that there was an acceptable level of correlation between the binding score values and the available aromatase inhibition data. This means that the homology models derived on bird and fish species can be used to approximate the potential inhibitory effects of azoles on their aromatase.

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Section: Resultsmentioning

confidence: 99%

Modelling inhibition of avian aromatase by azole pesticides

Saxena¹,

Devillers²,

Bhunia

et al. 2015

SAR and QSAR in Environmental Research

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“…In the contrast, the administration of high doses of TAM caused blockage of oestrogen receptors leading to a progressive decrease in the laying of eggs before their complete cessation [ 8 ]. TAM‘s impact at different ages has been studied, either by ova inoculation to estimate its influence on sex determination as a modulator for oestrogen receptors [ 9 , 10 , 11 , 12 ] or hatch day [ 9 ] or even older ages to assess its impact on hormonal profile and reproductive system [ 6 , 13 , 14 ]. Additionally, the various administration techniques of Tamoxifen were studied: in-ovo inoculation [ 9 ], per os in gelatine capsules [ 15 ] and intra muscular injection as well as the use of different preparation doses, e.g., 0.5; 1.0; 5.0; 10.0 or even 25 mg/kg body weight.…”

Section: Introductionmentioning

confidence: 99%

Impact of Oral Supplementation of Different Levels of Tamoxifen on Productive and Reproductive Efficiencies and Carcass Traits of Avian48 and Arbor Acres Broilers

Younis

Aboelnour

Swelum

et al. 2020

Animals

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This research was aimed at estimating the effect of oral supplementation of Tamoxifen on productive efficiency, carcass characteristics, hormonal profile and gonadal structure of two broiler breeds. One hundred and eighty chicks of each breed of Avian48 and Arbor Acres were divided into three groups: control group; TAM10 group, supplied with 10 mg Tamoxifen/kg of body weight at 3, 5, 7 and 9 days of life; and TAM20 group, supplied at the same intervals with 20 mg Tamoxifen/kg of body weight. Both levels of Tamoxifen improved productive performance at early ages, but Arbor Acres produced better results with TAM20 levels than TAM10, while Avian48 breeds reacted adversely. On the contrary, Tamoxifen supplementation significantly decreased feed intake and feed conversion (after the first two weeks of life) compared to control with a higher level of decrease reported for TAM20 treatments than TAM10 and for Arbor Acres compared to Avian48 breed. Carcass traits were not affected significantly with Tamoxifen supplementation compared to control although Arbor Acres responded better to TAM20 and Avian48 for TAM10. With regard to the effect of Tamoxifen (TAM) on sex hormones, it could be concluded that TAM10 treatments showed a stimulating effect on the level of such hormones as compared with the TAM20 group with the most favourable results being clearly detectable in 42-day-old birds although both concentrations of Tamoxifen did not differ significantly from control. However, treatment of broiler chickens with Tamoxifen in different doses caused a gradual decrease in follicle production rate and eventually led to an increase of the atretic follicles in different stages of atresia. Finally, we can conclude that Tamoxifen supplementation can improve performance and carcass efficiency of broilers without changing the hormonal profile, however much research is required to estimate the best concentration required for each breed.

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“…Injection of tamoxifen on the first day of egg incubation led to the results described for the later periods of egg incubation (on the fourth day) and less significant than with letrozole [16]. There was a slight (1.5 times) hypertrophy of both testes in males.…”

Section: Resultsmentioning

confidence: 74%

“…According to our data, the effect of letrozole as an aromatase inhibitor is clearly evident when its injections are carried out into the eggs at the first day of incubation. There is inversion of sex (female to male) in almost 100% of cases (Table 1), whereas for the usual way of microinjection at 3 -4 day of egg incubation phenomenon is less pronounced [16] [17]. Earlier it was noted that in birds the expression of aromatase is observed only on day 5 of embryonic development; on day 2 there are other enzymes involved in the synthesis of precursors of sex hormones [18].…”

Section: Discussionmentioning

confidence: 95%

Experimental Sex Inversion of Chicken Embryos at Aromatase Inhibition, Estrogen Receptor Modulation, DNA Demethylation and Progesterone Treatment

Trukhina¹,

Лукина²,

Smirnov³

2016

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The work was carried out by microinjections of an aromatase inhibitor letrozole, an estrogen receptor modulator tamoxifen in incubated eggs Gallus g. domesticus, the first day of incubation. It also used 5-azacytidine (5-AC) at the same time. Injection of progesterone was carried out before the onset of meiosis prophase 1 on 16 h of incubation. Morphologically and histologically and by PCR, sex of the 17-day embryos was controlled. According to information received microinjection of letrozole caused almost a 100% inversion of genetic males to females, which is manifested in the morphology of the gonads. In other experiments, sex reversal is not revealed. The results are obtained in this study, and the data suggest that the presence of gonadogenesis in female chickens makes earlier emergence of aromatase in the beginning of incubation, than that according to the classical scheme of sex determination in birds. Presumably this kind of synthesis is triggered by some W-chromosomal factors. It failed to detect the phenomenon of gender inversion-the transformation of males into females after exposure to demethylating agent 5-AC that casts doubt on the participation of male hypermethylated (MHM)-RNA-segment in regulating the activity of sex determining genes.

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Sex inversion in domestic chicken (Gallus gallus domesticus) by letrozole and tamoxifen

Cited by 8 publications

References 30 publications

Modelling inhibition of avian aromatase by azole pesticides

Modelling inhibition of avian aromatase by azole pesticides

Impact of Oral Supplementation of Different Levels of Tamoxifen on Productive and Reproductive Efficiencies and Carcass Traits of Avian48 and Arbor Acres Broilers

Experimental Sex Inversion of Chicken Embryos at Aromatase Inhibition, Estrogen Receptor Modulation, DNA Demethylation and Progesterone Treatment

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