References of "Mélard, Charles"
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See detailElevated amh Gene Expression in the Brain of Male Tilapia (Oreochromis niloticus) during Testis Differentiation
Poonlaphdecha, S.; Soler, P.; Sheng-Hui, H. et al

in Sexual Development (2011), 5(1), 33-47

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See detailDoes domestication process affect stress response in juvenile Eurasian perch Perca fluviatilis ?
Douxfils, Jessica; Mandiki, S. N. M.; Marotte, Grégory et al

in Comparative Biochemistry and Physiology. A : Comparative Physiology (2011), 159

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See detailPhysiological and proteomic evidences that domestication process differentially modulates the immune status of juvenile Eurasian perch (Perca fluviatilis) under chronic confinement stress.
Douxfils, J.; Mathieu, Cédric; Mandiki, S. N. et al

in Fish & Shellfish Immunology (2011), 159(1), 92-9

The current study aimed to evaluate the influence of domestication process on the stress response and subsequent immune modulation in Eurasian perch juveniles (Perca fluviatilis) submitted to chronic ... [more ▼]

The current study aimed to evaluate the influence of domestication process on the stress response and subsequent immune modulation in Eurasian perch juveniles (Perca fluviatilis) submitted to chronic confinement. Briefly, F1 and F4 generations were confined into small-size tanks and sampled 7 and 55 days after stocking. Cortisol and glucose levels as well as lysozyme activity and immunoglobulin level were evaluated in the serum. Spleen Somatic Index and spleen ROS production were also measured. A proteomic analysis was performed on serum sampled on day 7. Finally, both generations were genetically characterized using a microsatellite approach. Globally, results revealed that chronic confinement did not elicit a typical stress response but resulted in a prolonged immune stimulation. Proteomic results suggested that domestication process influenced the immune status of perch submitted to chronic confinement as the F1 confined fish displayed lower abundance of C3 complement component, transferrin and Apolipoprotein E. Microsatellite data showed a strong genetic drift as well as reduced genetic diversity, allelic number and heterozygosity along with domestication process. The present work is the first to report that fish under domestication can develop an immune response, assessed by a combined approach, following recurrent challenges imposed by captive environment despite a reduced genetic variation. [less ▲]

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See detailEffect of Chronic confinement stress on growth, survival, blood cortisol and glucose of perch (Perca fluviatilis)
Rougeot, Carole ULg; Tomson, Thomas; Vandecan, Michaël et al

Poster (2011)

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See detailEffect of partial or total replacement of forage fish by a dry diet on the quality of reproduction in pikeperch, Sander lucioperca
Wang, Neil; Mandiki, S. N. M.; Henrotte, Emilie et al

in Aquaculture Research (2009), 40(3), 376-383

The aim of this preliminary study was to evaluate the influence of different feeding regimes on the quality of reproduction in pikeperch. Three diets were tested: forage fish (FF), a commercial dry feed ... [more ▼]

The aim of this preliminary study was to evaluate the influence of different feeding regimes on the quality of reproduction in pikeperch. Three diets were tested: forage fish (FF), a commercial dry feed (DD) and a mix of both (FD). The diets were given to fish throughout a complete reproductive cycle. During the spawning season, couples were injected with human chorionic gonadotropin (hCG) and let to spawn on nests. Proportion of running males, spawning and hatching success and larval quality (weight, length, body protein, total lipid, fatty acid and lipid class compositions and resistances to osmotic shock and starvation stress tests at hatching) were evaluated. The proportion of running male was lower in the DD group than in the FF and FD groups (54% for DD against 76-89% for FF and FD). In addition, 25%, 62.5% and 75% of injected couples gave spawning that hatched in DD, FF and FD groups respectively. Larval quality parameters were not significantly different between treatments. The results indicate that overall quality of reproduction was higher in FF and FD treatments than in DD. It suggests that the dry feed used was not totally adequate for pikeperch reproduction. Relations between breeder reproductive performances and the feed compositions are discussed. [less ▲]

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See detailOvarian steroidogenesis inhibition by constant photothermal conditions is caused by a lack of gonadotropin stimulation in Eurasian perch
Milla, S.; Mandiki, S. N. M.; Hubermont, P. et al

in General and Comparative Endocrinology (2009), 163(3), 242-250

In fish, the reasons for the inhibition of reproduction by constant photothermal conditions of rearing are far from clear. In an in vivo experiment, two groups of females reared under natural (4-28 ... [more ▼]

In fish, the reasons for the inhibition of reproduction by constant photothermal conditions of rearing are far from clear. In an in vivo experiment, two groups of females reared under natural (4-28 degrees C) or constant photothermal conditions (20-22 degrees C, photoperiod 12/12) were investigated for gonad development, sex-steroids (testosterone-T, 17-beta-estradiol-E2 and 11 Keto-Testosterone-11KT) dynamics and brain aromatase activity in January, February and March. Two days before each sampling date, a group of females reared under constant conditions was injected with HCG (Human Chorionic Gonadotropin: 100 Ul/kg) and evaluated for the same parameters. In addition, in vitro ovarian steroidogenesis capacity for each female was determined with or without stimulation by HCG and/or IGF-1 (insulin-like Growth Factor-1). The results indicate that vitellogenesis stage is the limit ovarian stage never reached in females submitted to constant photothermal conditions. This was associated with gonadogenesis delay and low levels of circulating sex-steroids (T, E2 and 11KT). Nevertheless, HCG injections partly counteracted the plasma steroid deprivation, indicating that ovaries from fish reared under constant photothermal conditions suffer from a lack of gonadotropin stimulation, maybe caused by plasma LH suppression. Such finding was confirmed by the in vitro ovary incubation test. HCG and IGF-1 treatments induced broad testosterone and 17-beta-estradiol elevations and the exposure to constant photothermal conditions, in some cases, decreased that response to HCG. In conclusion, we show that the inhibition of reproductive cycle in Eurasian perch females by constant photothermal conditions of rearing may be related to lower sex-steroid levels and to an inhibition of ovarian regulation by gonadotropins (at least LH), probably stopping gonadogenesis before vitellogenesis stage. (C) 2009 Elsevier Inc. All rights reserved. [less ▲]

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See detailSexual dimorphism in two pure cichlid species, Oreochromis niloticus and Sarotherodon melanotheron, and their intergeneric hybrids
Toguyeni, A.; Fauconneau, B.; Mélard, Charles ULg et al

in African Journal of Aquatic Science (2009), 34

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See detailGenetic Improvement of Growth in perch production: domestication, sex control, hybridization and strain selection.
Rougeot, Carole ULg; Mélard, Charles ULg

in Proceedings of the internationl workshop on Percid Fsih Culture (2008)

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See detailChapter6 : Genetic Improvement of Growth
Rougeot, Carole ULg; Mélard, Charles ULg

in Farming Of Eurasian perch. Volume 1: Juvenile production. (2008)

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See detailEffect of high temperature during embryogenesis on the sex differentiation process in the Nile tilapia, Oreochromis niloticus.
Rougeot, Carole ULg; Prignon, Christian ULg; Ngouana Kengne, Cyrille Valence et al

in Aquaculture (2008), 276

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See detailEarly sex reversal during the embryonic development in the Nile tilapia
Rougeot, Carole ULg; Kanfitine, Samane, Yadja; Prignon, Christian ULg et al

in Cybium (2008), 32(2), 104-105

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See detailEffect of sexual genotype on the reproductive biology of the Nile tilapia, O.niloticus.
Rougeot, Carole ULg; Badiane, A. A.; Prignon, Christian ULg et al

Poster (2007, June)

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See detailSex steroid dynamics during embryogenesis and sexual differentiation in Eurasian perch, Perca fluviatilis
Rougeot, Carole ULg; Krim, A.; Mandiki, S. N. et al

in Theriogenology (2007), 67(5), 1046-1052

It is widely accepted that sex steroid hormones play an important and a specific role during the process of sex differentiation in fish. In order to describe the role of the three main sex steroid ... [more ▼]

It is widely accepted that sex steroid hormones play an important and a specific role during the process of sex differentiation in fish. In order to describe the role of the three main sex steroid hormones (testosterone--T, 17beta-estradiol--E2 and 11keto-testosterone--11KT) during embryogenesis and sex differentiation in Eurasian perch, Perca fluviatilis, eggs, larvae and juveniles originating from two mixed-sex and two all-female progenies were regularly sampled from fertilization to hatching (D0) and from hatching to day 70 post-hatching (D70). Just after spawning, a significant amount of sex steroids [T (1634.2pgg(-1)), E2 (554.4pgg(-1)) and 11KT (1513.2pgg(-1))] was measured in non-fertilised eggs suggesting a maternal transmission of these steroids. From D2 to D70 post-hatching, E2 levels were significantly higher in mixed-sex progenies (median: 725.7pgg(-1)) than in all-female progenies (156.2pgg(-1)) and significantly increased after the onset of the histological differentiation of the gonad in both progenies (D35). Levels of 11KT were significantly higher in mixed-sex (median: 431.5pgg(-1)) than in all-female progenies (below the limit of assay detection) and significantly increased at D35 in all-female progenies (median value: 343.2pgg(-1)). Mean 11KT to E2 ratio was six-fold higher in mixed-sex progenies (1.35) than in all-female progenies (0.24). The data suggest that the 11-oxygenated androgen (11KT) plays a major role in the male differentiation process, and that sex differentiation in Eurasian perch is probably determined by the 11KT to E2 ratio. [less ▲]

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See detailStudy of sex ratio in progeny of a complex Oreochromis hybrid, the Florida red tilapia
Desprez, D.; Briand, C.; Hoareau, M. C. et al

in Aquaculture (2006), 251(2-4), 231-237

This paper reports a study on the progeny sex-ratio distribution in the Florida red tilapia. This hybrid originated as a cross between O. mossambicus male and O. urolepis hornorum female, which was then ... [more ▼]

This paper reports a study on the progeny sex-ratio distribution in the Florida red tilapia. This hybrid originated as a cross between O. mossambicus male and O. urolepis hornorum female, which was then crossed with 0. niloticus and 0. aureus in order to improve its growth rate and its resistance to low temperature. We have studied the sex-ratio of I I I progenies from 46 females and 12 males, where the male percentage varied between 5% to 89%. The analysis of distribution showed three groups characterised by a mean male percentage of 26.7 +/- 9.81; 50.0 +/- 8.9 and 70.3 +/- 5.5%. The stability of sex ratios in repeated single pair matings and the parental influence on progeny sex ratios obtained are in agreement with a polygenic basis of sex determination in this complex hybrid. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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