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Master Thesis

Analyse histologique des gonades, du foie, du rein et de l’état physiologique du tilapia du Nil Oreochromis niloticus exposé aux pesticides agricoles dans les retenues d’eau du Nord-Bénin

Abstract : Current agricultural practices in the Beninese cotton basin located at north-east of the country involve the heavy use of pesticides which constitute the major pollutants in this area. The present study carried out in the rainy season, used the histology of organs, the morpho-physiological indices and the growth parameters as complementary biomarkers to evaluate the health status of Oreochromis niloticus caught directly in open water, raised in pens and in “happas” installed in two water reservoirs of northern Benin. This is Songhaï water reservoir, reference site situated outside the cotton basin and Batran water reservoir located in the town which consumes the most agricultural pesticides in Benin. The histological results show that the gonads, liver and kidney of Oreochromis niloticus collected at Batran are most affected by alterations which are in most regressive. Regardless of the water reservoir and sex, all the six stages of development are present in the gonads. The pesticide cocktail effect in the Batran reservoir seems to be androgenic i.e. this complex mixture of pesticides retards the maturation of oocytes and accelerates the sperm one. The liver and testis are the Oreochromis niloticus organs most altered. The general health of fish sampled in Batran water reservoir is dangerously affected more compared to those from reference site, similarly, male fish are the most affected. Whatever the month, fish caught directly in open water of Songhaï reservoir have the gonadosomatic index (GSI), the hepato-somatic index (HSI) and the condition index (K) significantly higher compared to those from Batran water reservoir ( p <0.05 for the females). In the same reservoir, whatever the sex, the values of biometric indices are higher in “happas” comparatively to pens. All the biometric indices of fish caught in pens at Songhaï water reservoir are higher than those caught in pens at Batran; only IHS and K for females show a significant difference (p <0.05). In “happas”, biometric indices of fish caught at Songhaï are also higher than those collected at Batran water reservoir with a significant difference between K for the females (p <0.05). Regardless of the water reservoir, the average weight gain (WG), the individual average daily gain (ADG) and specific growth rate (SGR) are significantly higher in happas (p <0.05). Compared to the Batran water reservoir, the fish raised in Songhaï water reservoir show the best growth parameters (p <0.05).
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https://dumas.ccsd.cnrs.fr/dumas-02878839
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Submitted on : Tuesday, June 23, 2020 - 12:32:45 PM
Last modification on : Friday, October 23, 2020 - 4:41:15 PM
Long-term archiving on: : Thursday, September 24, 2020 - 4:46:46 PM

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Rodrigue Pelebe. Analyse histologique des gonades, du foie, du rein et de l’état physiologique du tilapia du Nil Oreochromis niloticus exposé aux pesticides agricoles dans les retenues d’eau du Nord-Bénin. Biologie animale. 2016. ⟨dumas-02878839⟩

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