Konan et al. J. Appl. Biosci. 2013. Caractérisation de la reproduction de Thysochromis ansorgii dan la foret des marais, Cote d'Ivoire 5716Reproductive characteristics of Thysochromis ansorgii (Pisces, Cichlidae) in the Tanoe-Ehy swamp forest (Côte d'Ivoire) Abstract: Objectives: The study investigates the reproductive traits of Thysochromis ansorgii (Boulenger, 1901) in the Tanoe-Ehy swamp forest (Côte d'Ivoire) which is characterized by acute seasonal variations of some environmental variables. Methodology and results: Fish capture, using fyke nets and fish traps, and environmental variable (temperature, dissolved oxygen, and water depth) measurements as well were done monthly from March 2012 through February 2013. Sex ratio for all fishes (1:0.9) was slightly in favour of female and size at first maturity was 68.5 and 80.9 mm SL for females and males respectively. The main breeding seasons determined (April-July and October-December) coincided with the rainy seasons (or sampling site flooded seasons) in which females produced more oocyts comparatively to the dry months. Conclusion and application of results: This study showed that temperature, dissolved oxygen and hydrological conditions have direct impact on both length of breeding period and the amount of oocyts produced by females. These data help suggest a closure of T. ansorgii capture by fishermen during April-June period in order to allow the majority of mature fishes to reproduce. In addition, the choice of fish capture gears (mainly gillnets) might refer to the maturity size determined for T. ansorgii.

No abstract

L'étude avait pour but d'évaluer les effets de l'incorporation des graines torréfiées de niébé dans l'alimentation de la poule locale en ponte, sur ses performances zootechniques et économique. Six coqs et soixante poules de race locale de 7,5 mois d'âge ont été répartis en six lots, par tirage aléatoire. Deux régimes alimentaires aux mêmes contraintes nutritionnelles dont un témoin et un régime expérimental comportant 8% de graines torréfiées de niébé ont été préparés. La ponte, les caractéristiques des oeufs, les consommations et les mortalités sont suivies hebdomadairement pendant 24 semaines. L'éclosion des oeufs a été suivie durant 03 semaines. La marge brute induite par chaque régime a été évaluée à la fin de l'essai. Au terme de l'étude, les taux de ponte, d'éclosions et l'indice de consommation ont été respectivement de 30,52%, 58,70% et 8,37% pour le régime expérimental, contre 29,67%, 53,81% et 8,52% pour le témoin. Les marges brutes ont été de 4807,82 FCFA pour le régime expérimental et de 4818,89 FCFA pour le témoin. Cependant, aucune différence significative n'est observée entre les paramètres mesurés (P>0,05). Ceci suggère que les graines torréfiées de niébé peuvent être incorporées dans l'alimentation des poules locales en ponte, comme source de protéines.

Influence de la salinité sur la structure des branchies et l'ultrastructure des ionocytes chez le tilapia provenant d'un estuaire hypersalé (Sénégal).

The present study was carried out to study the preferred prey in the larval and post-larval stages of Heterobranchus lonsifilis. Two hundred and forty larvae and fry of H. longifilis aged 2 to 23 days were stored in aquariums of 8 liters, fasted for 24 hours at the end of which they were fed to satiety with freshly collected zooplankton from fishponds. The day after feeding, the fish were euthanized and stored for stomach contents examination. The results showed that the zooplanktonic population density of the station ponds was 1356.73 individuals / L. This stand is composed of Cladocerans (455.85 individuals /l), nauplii (289.11 individuals / l), Rotifers (255.47 individuals / l), Copepodites (182.21 individuals / l) and Copepods adults (174.07 individuals /l). Furthermore, examination of stomach contents showed that adult Copepods were the most frequent and abundant prey category in stomach contents in terms of frequency of occurrence (66.7%) and numerical percentage (48.25%). In addition, these preys (adult copepods) constituted the preferred zooplankton prey in larvae and post-larvae of H. longifilis with an electivity index (E) equal to +0.5. Apart from the first size classes in which no prey has been observed in the stomach contents, the food preferences of H. longifilis larvae and fry do not vary with the size of the individuals. This study showed that adult copepods were the preferred zooplankton prey of H. longifilis larvae and fry.