Purpose Rising demand of fish generates various pressures on aquatic ecosystems, causing its deterioration and the loss of its biodiversity. With the aim of a better management and fish production in a salubrious environment, this study proposes the utilization of organic fertilizers from rabbit manure. Methods The treatments consisted of manure of rabbits fed with: manufactured diet (T 1 ), improved diet with Ipomea aquatic (T 2 ), improved diet with Elaeis guineensis (T 3 ), and improved diet with Panicum maximum (T 4 ). Indeed, experimental design was a completely randomized block design with three replications. 6 g in 10 L of water from the different manures from each diet was followed during 50 days. Various nutrients were measured. Results After the mineralization process, the best manure which released more nutrients was T 4 with measured proportions of N-NO 2 -, N-NO 3 -, N-NH 3 , P-PO 4 3-, Ca 2? , Mg 2? , K ? , and suspended matter being 0.06 ± 0.0, 0.38 ± 0.1, 0.85 ± 0.1, 8.27 ± 0.9, 12.11 ± 0.8, 4.47 ± 0.3, 3.02 ± 0.2, and 140.78 ± 18.6 mg/L, respectively. The highest content of phosphorus and nitrogen was recorded in T 4 and T 2 , respectively. The principal component analysis showed a positive correlation between P-PO 4 3-, Ca 2? , Mg 2? , MES, conductivity, and salinity during mineralization.Conclusion Manure from rabbits fed by an improved diet with P. maximum (T 4 ) was recommended for agro-piscicultural production system.
A reliable characterization of cladocerans' growth kinetic on their substrates is crucial for the estimation of their biochemical conversion rate in pond models. Although many studies reported cladocerans' growth inhibitions by high chlorophyceae contents, their growth kinetics had continued to be described in many pond system models by Monod-type kinetic, which describes growth saturation by high substrate contents, but fails to explain the disappearance of cladocerans observed during chlorophyceae's bloom periods. This study aimed to develop a methodology and assess whether growth-inhibition-type models used to describe microbial growth kinetics can be applicable to cladocerans. Experiments were carried out using Daphnia pulex populations and Scenedesmus sp. First, biomass of D. pulex was measured through digital image processing (DIP) during growth experiments. Then, three candidate models (i.e., Andrews, Edward and Haldane models), along with the Monod model, were fitted to the observed data and compared. The results showed that the DIP technique provided reliable results for estimating the biomass of D. pulex. Our findings show that the candidate growth inhibition-type models satisfactorily described D. pulex's growth kinetic (86% variance accounted for). Scenesdemus sp. were not strong inhibitors of the growth of D. pulex (high inhibition constant and low half-saturation constant found).
Les systèmes intégrés de production constituent l'une des voies essentielles pour une agriculture durable. Cette étude a pour but d'évaluer l'effet d'une alimentation à base de Azolla filiculoïdes, Elaeis guineensis, Ipomoea aquatica et Panicum maximum sur les performances zootechniques des lapins et le potentiel nutritif des crottes de lapins qui en résultent sur l'aquaculture. Pour ce faire, trente-six (36) lapereaux sevrés de trois (3) semaines d'âge et pesant en moyenne 70,08 ± 0,04g chacun, ont été utilisés pour l'expérimentation. Ces lapereaux ont été répartis en quatre (4) lots de trois (3) lapereaux chacun, disposés dans des cages. Le lot 1 a reçu l'aliment conventionnel VETO SA vendu sur le marché béninois (cet aliment est désigné ici R 0), les lots 2, 3 et 4 ont reçu respectivement un régime complété avec Ipomea aquatica R 1 (Ia), Elaeis guineensis (feuille) R 2 (Eg), et Panicum maximum R 3 (Pm). Des toiles de moustiquaires ont été suspendues en dessous des cages pour recueillir les crottes. Les lapereaux nourris au régime complété avec Panicum maximum ont eu un gain moyen journalier de 76,19 ± 8,24 g/j contre 61,90 ± 8,21 g/j pour R 0 et R 2 (Eg) et 54,76 ± 14,86 g/j pour R 1 (Ia) par cage. Le régime complété au Panicum maximum donne de bonnes performances zootechniques et constitue un atout économique pour les cuniculteurs. Les ratios N/P/K des crottes observés respectivement pour R 3 (Pm), R 2 (Eg), R 1 (Ia)
RESUME Objectif : La présente étude vise à évaluer la pollution fécale des eaux usées de Cotonou, ville la plus peuplée du Bénin. Méthodologie et Résultats : Trois stations correspondant au point de rejet de trois collecteurs ont été échantillonnées durant une période de 11 mois allant de Janvier à Novembre 2013. La température, le pH, la conductivité électrique et la teneur en oxygène dissous ont été mesurés in situ. Le dénombrement des bactéries indicatrices de contamination fécale a été réalisé par la méthode d'ensemencement par incorporation en milieu nutritif spécifique. Les charges enregistrées pour les différentes bactéries dénombrées ont été hors normes et atteignent respectivement 4,32.10 6 , 1,30.10 7 , 4,30.10 6 et 7,90.10 4 UFC/100ml pour Escherichia coli, les coliformes totaux, les streptocoques fécaux et les anaérobies sulfito-réducteurs. Les valeurs notées pour les paramètres physico-chimiques ont été aussi irrégulières par rapport aux normes de rejet mais favorables pour la plupart au bon développement des microorganismes. Conclusions et application : Les eaux résiduaires étudiées sont considérablement chargées en germes fécaux. Ceci indique une importante contamination fécale, source potentielle d'épidémie. Leur épuration est donc nécessaire avant leur rejet dans l'environnement afin de lever la menace qu'elles constituent pour la santé publique.
Description du sujet. Déterminer les conditions optimales d’utilisation des effluents de brasserie en production de phytoplancton. Objectifs. Déterminer le potentiel nutritif, les conditions d’utilisation et la dépollution réalisée suite à l’utilisation d’effluents de brasserie en aquaculture. Méthode. Le surnageant a été analysé. Ensuite, cinq traitements ont été ensemencés de Scenedesmus quadricauda et suivis (biomasses et paramètres physico-chimiques) pendant 27 jours. Finalement, les taux d’abattements des charges polluantes initiales ont été déterminés. Résultats. Le surnageant n’est pas conforme à la norme béninoise, mais présente un potentiel nutritif élevé. La non-neutralisation du pH, initialement acide, occasionne un démarrage tardif de la croissance algale. Le traitement à 10 % présente la production maximale et d’importants abattements de charges polluantes. Conclusions. Dans un contexte où il n’y a pas de station d’épuration fonctionnelle, il serait intéressant d’envisager un partenariat gagnant-gagnant entre les brasseries et les pisciculteurs. Les conditions optimales d’utilisation incluent une dose optimale et une neutralisation préalable du pH.
Due to costs of setting up and operating electrical stirring systems to keep algae in suspension and exposed to light, cultivation of monospecific algae is poorly expanded in developping countries. However, some algal species such as Arthrospira platensis, are equipped with gaseous vesicles that allow them to stay afloat and increase their exposure to light. In this study, we investigated in an unstirred outdoor environment, its growth kinetic and purifying performance in a brewery effluent-based media. Batch cultures were carried out in three experimental treatments and evolution of physicochemical and growth parameters were monitored. Then its contribution to depollution was determined. Results show that optimal conditions for producing A. platensis include the culture tank transparency, the effluent dilution (i.e. 10%), and the culture media amendment with sodium bicarbonate and sodium nitrate. The average productivity recorded reached 0.55 g DW·L−1·d−1 during the exponential growth phase, while preserving culture from contamination. COD and total Nitrogen concentrations were reduced for 32.5% and 64.91%. Such results open up prospects for low-cost production of certain algae, in transparent and relatively high barrels, thus breaking, the classic barriers related to shallow basin depth and mechanical agitation traditionally considered as critical to the success of algal production.
In order to determine the optimal dose of rabbit manure for plurispecific production of fresh water zooplankton in controlled area, the effects of six different doses of dry rabbit manure (T1 = 300 g/m 3 , T2 = 600 g/m 3 , T3 = 900 g/m 3 , T4 = 1200 g/m 3 , T5 = 1500 g/m 3 , T0 = 0g/m 3 ) on physico-chemical and biological parameters of areas were monitored for 27 days in cultures realized in plastic buckets of 80 L capacity each. Manures are from rabbits fed with diet previously revealed favorable to their growth, and is made of 2% of dried cassava, 30% of maize bran, 10% of palmist cake, 10% of soya cake, 5% of cotton cake, 2% of shell, 10% of malt, 5% of beer yeast, 10% of Panicum maximum and 1% of salt. Six days after fertilization, buckets were seeded with zooplankton by 26 individuals per liter (ind/L). Results obtained show that the supply of rabbit manure has improved chemical properties and microalgae production (phytoplankton) with treatments T1, T2, T3, T4 and T5. Optimal conditions of zooplankton production through phytoplankton are obtained with doses in T2 and T4 which present the best specific growth rate. The daily production through the highest phytoplankton biomass (chlorophyll-a) has been obtained with dose in T5. Thus, doses 600 g/m 3 and 1200 g/m 3 of rabbit manure may be considered optimal for a plurispecific production of fresh water zooplankton. It was noted that Rotifers were predominant in abundance in almost the different culture areas.Keywords Rabbit manure; Optimal dose; Zooplankton; Plurispecific production BackgroundThe natural feed appreciated by fish larvae is essentially made of zooplankton and artificial dry feed are not always appropriated to this premature stage (Arimoro, 2005). Consequently, zooplankton such as cladocerans, copepods and rotifers are used for larval rearing by many researchers in controlled area (Awaïss et al., 1992). Artemia (live food) is the most used for certain marine species whose hatching, development and growth were realized in pond (Agadjihouèdé et al., 2011). Nevertheless, it remains less effective in fresh water fish larvae. Artemia as larvae food is inaccessible to rural fish farmers (Fiogbe et al., 2003). Indeed, its use doesn't always give good zootechnical performances to fresh water fishes. Zooplankton production in controlled area is carried out in many studies, by the way of phytoplankton production using different types of fertilizer (chemical, organic genuine vegetal or animal) (Adande et al., 2015). Chemical fertilizers (minerals) are the former used for phytoplankton production for the purpose of zooplankton production (Boyd et al., 2008) while organic fertilizers genuine vegetal or animal are the second used (Dalme et al., 2011). Between these two categories of fertilizer, the first type is dangerous to the environment and also expensive while the second type is less expensive and does not present any risk for the environment (Agadjihouèdé et al., 2011;Adande et al., 2017). These findings justify nowadays the easy use of organic...
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