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The silver catfish Schilbe intermedius (Ruppell, 1832) is single-spawning species spread in Africa and may reach 50 cm in length. Since there are no studies on the artificial reproduction of S. intermedius, the aim of the present study was to induce for the first time spawning by hormonal injection and to determine the reproductive parameters for this species. Artificial induction was carried out by the injection of Ovaprim (0.5 ml kg− 1) to males and females. Different eggs measurements were carried out by micrometer. Egg stripping was carried out ten hours after hormone injection at 27.17 ± 0.22 °C (mean ± standard deviation) with mean spawning rate 58.15 ± 2.88 %. Relative fecundity was 613.25 ± 71.83 oocytes/g with mean diameters 0.94 ± 0.10 mm and 1.11 ± 0.06 mm, respectively, before and after eggs fertilization. Fecundity and hatching rates ranged, respectively, from 60.30 to 68.02 % and 56.11–60.96 %. Egg hatching occurred about 22 or 28 h after fertilization at 26.02 °C, and the larvae average length was 1.24 ± 0.14 mm. Yolk sac resorption occurred 48 h after hatching and larvae acquired their morphological structures in about 72 h after hatching. This information will be important in improving the artificial reproduction protocols of S. intermedius in controlled breeding programs.

Ethno-ichthyological knowledge can improve fisheries management. This study covers interactions between ecological, morphological, and sociocultural aspects pertaining to the fish of the Tovè River, which is located in the largest fishing area in the Republic of Benin (Ouémé Valley), West Africa. In particular, data were collected on fishing methods and techniques, fishing equipment, and ichthyofauna by noting vernacular names followed by identification traits, taste and dietary value, medicinal use, and related knowledge of different species. Through data related to names given locally to fish, this paper highlights the manner in which physical or behavioral traits are coded in terminology. Most of these species have a high market value, either because they are considered to be delicacies and/or for their medicinal uses. The results suggest that ethno-ichthyological information can successfully be applied to improve fish conservation and fisheries management.

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. The treatments consisted of manure of rabbits fed with: manufactured diet (T1), improved diet with Ipomea aquatic (T2), improved diet with Elaeis guineensis (T3), and improved diet with Panicum maximum (T4). 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. After the mineralization process, the best manure which released more nutrients was T4 with measured proportions of N-NO2 −, N-NO3 −, N-NH3, P-PO4 3−, Ca2+, Mg2+, 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 T4 and T2, respectively. The principal component analysis showed a positive correlation between P-PO4 3−, Ca2+, Mg2+, MES, conductivity, and salinity during mineralization. Manure from rabbits fed by an improved diet with P. maximum (T4) was recommended for agro-piscicultural production system.

Chloroscombrus chrysurus (Linnaeus 1766) is one of the most abundant species of Carangidae family occurring in the nearshore waters of Benin. To ascertain the exploitation level of this fishery resource, some demographic parameters of the species were studied for management and conservation measures. 605 specimens were collected randomly from commercial catches from August to November 2014. Morphometric, meristic and weight data were analyzed using SPSS software and the ELEFAN I routine from FiSAT. The population of C. chrysurus was not heterogeneous with a sex-ratio of 1.4:1 (p < 0.05; χ² = 312.485) and masculinity and femininity rates were 58.31% and 41.69% respectively. Length frequencies showed low percentage of small sized individuals and independent distribution of sex (r = 0.16, p < 0.05). The monthly variations of the gonad-somatic index (GSI) and the condition factor (Kc) showed a decreasing trend over the review period and corresponding probably to the period of gametes emission. von Bertalanffy growth parameters estimated were L ∞ = 28.35 cm, K = 0.49 year -1 , t 0 = -0.33 year and φ’ = 2.59. Total mortality, natural mortality and fishing mortality are 1.39, 1.17 and 0.22 respectively. The exploitation rate (E = 0.16) showed that the resource was underexploited implying that the purse seine is not a danger for this species.

Objectifs: Cette etude vise a evaluer les effets de la densite de mise en charge des alevins de Parachanna obscura eleves en captivite sur leurs performances zootechniques et leur production. Methodologie et resultats: Les densites de 10, 15, 20 et 25 alevins / dm 3 d’eau ont ete testees sur les alevins de P. obscura de poids moyen initial 9,6 g nourris au Coppens pendant huit semaines. Chaque densite a ete testee en triplicat. Les resultats obtenus montrent que la densite de mise en charge n’a pas eu d’effet significatif sur le taux de survie qui a ete de 100% pour tous les traitements appliques. Cependant, les parametres de croissance et d’utilisation des aliments ont significativement varie en fonction des traitements (P < 0,05). Le taux de croissance specifique, l’efficacite alimentaire et la production les plus eleves ont ete obtenus avec la densite de 25 alevins / dm 3 d’eau. Conclusion et application: Les alevins de P. obscura sont tres resistants et peuvent etre stockes a une densite optimale de 25 alevins / dm 3 d’eau afin d’augmenter la production et la rentabilite technique et economique des entreprises aquacoles. Mots cles: Parachanna obscura , alevins, densite, performances zootechniques, production English Title: Effect of stocking density on zootechnical performances and production of Parachanna obscura fingerlings reared in captivity English Abstract Objective: The aim of this study is to evaluate the effects of stocking density on zootechnical performances and production of P. obscura fingerlings reared in captivity. Methodology and results: Four stocking densities (10, 15, 20 and 25 fingerlings / dm 3 ) were tested on P. obscura fingerlings during 8 weeks. Fish with initial body weight 9.6 g were feeding with Coppens. Each treatment was assigned in triplicate. Results showed that in all treatments, survival rate were 100% and were not significantly affected by stocking density. However, growth and feed utilization parameters were significantly influenced by stocking density (P

To completely replace the fish meal by a mixture of earthworm and maggot meals, experimental diets were tested during 42 days on Clarias gariepinus fingerlings. Five isoproteic and isoenergetic diets (40 % crude protein and 17.9 ± 0.3 kJ g−1) including the control diet (D1) based on fish meal, were formulated. All these diets satisfied the essential amino acids requirements of C. gariepinus fingerlings. These diets were tested on triplicate groups of 50 fishes (initial body weight: 3 ± 0.1 g) bred in tank (0.5 m3). The approximate ratios 2:5; 1:4; 1:12 and 0:1 between the earthworm meal and the maggot meal were used, respectively, to formulate four diets D2, D3, D4 and D5 without fish meal. After the feeding period, significant differences (P

The purpose of the study is to evaluate the effect of different animal product wastes and plant compost on survival and growth of earthworm (Eisenia fetida). The study is realized in a vermibin for a duration of 90 days. The initial physico-chemical parameters (pH, humidity, ash, organic matter, carbon, nitrogen, phosphorus and C:N ratio) were determined in each waste of the different substrates before the study. Six waste products (pig, poultry, rabbit, cattle, sheep and vegetal compost) in triplicate (6 × 3) were used for earthworm production. In each 12-l content vermibin, 2 kg of substrate and 30 g of mature earthworms were sown. Each month, the growth control was realized by earthworms harvest and weighing. The earthworms were put back in substrate in vermibin and 500 g of substrate were completed. The pH was measured every week. The physico-chemical parameters (pH, ash, organic matter, carbon, phosphorus, nitrogen and C:N ratio) varied (P pig > rabbit > poultry > sheep > compost vegetable. The animal wastes (cow, sheep, pig, rabbit and poultry) and vegetable compost can be used to produce the earthworm. But the growth and produce depend on the biochemical quality of the substrates and the availability and facility for using a nutritive element.

The present study was conducted to compare the nutritive value of animal protein sources such as maggot meal (MM), earthworm meal (EM), termite meal (TM) and chicken viscera meal (CM) for fish feeding. Amino acids composition was determined in triplicate by HPLC method. These sources were rich in crude protein (54.30-71.8%), crude fat (10.7-18.7%) and crude fibre (5.7-9.7%). The total amino acid ranged from 18.8 to 57.19 g/100 g of crude protein and the percentages of essential amino acids were 61.58% (MM), 46.21% (EM), 32.02% (TM) and 45.72% (CM). CM was the richest in total acid amino acid (Aspartic acid and Glutamic acid) than other protein sources whereas basic amino acid (Histidine, Lysine and Arginine) was higher in MM than others. Leucine has the most concentrated amino acid in MM, EM and CM whereas there is phenylalanine in TM. Predicted protein efficiency ratio (P-PER 1 and P-PER 2 ) values were (2.16, 2.14) MM, (0.68, 0.67) EM, (0.79, 0.27) TM, and (1.20, 1.13) CM respectively; isoelectric point (pI) ranged from 1.10 to 3.65; chemical index (ICh) values were: (1.07) MM, (0.24) EM, (0.11) TM and (0.61) CM. Consequently, the results showed that MM was better at 76.47%, CM in 17.64% while TM was better at 5.88%. Based on these, maggot, earthworm and chicken viscera would be recommended as alternative protein sources to fish meal, especially maggot for fish feeding.

The domestication of new species in aquaculture, strongly contributed to the promotion of the aquaculture in the recent years. Fish need lipids, energy, protein vitamins and minerals in their feed for to insure growth, reproduction, and other physiological functions. Several studies have been made on P. obscura in sight of its domestication. Dietary protein requirement, dietary lipid requirement and dietary carbohydrate requirement of P. obscura were previously studied. The aim of this study is to make a bibliographical on the nutrient requirements of the African snakehead fish ( P. obscura ) in order to promote P. obscura rearing. Protein requirements of P. obscura larvae are between 45 and 55.5% whereas for fingerlings are 42.5 and 53.5% of the diet. The optimal carbohydrate requirement of P. obscura fingerlings is 12% of diet and maximum crude lipid is 7% of the diet.

Density is one of the important factors to be considered in frogs rearing. The current study aims to evaluate the effect of this parameter on the survival and growth of Hoplobatrachus occipitalis tadpoles in circular plastic ponds (Diameter: 24 cm; volume: 60 L) for 24 days. Four stocking densities (5, 10, 15 and 20 tadpoles/L), respectively represented by D 1 , D 2 , D 3 , and D 4 were tested on tadpoles (initial mean weight 0.283 ± 0.031 g) in triplicate. Tadpoles were daily fed at 6% of biomass every hour from 8 a.m to 6 p.m on Coppens fish feed. At the end of experiment, parameters such as final biomass (9.386 ± 0.240 to 23.750 ± 0.601 g), specific growth rate (1.960 ± 0.326 to 4.220 ± 0.255%/d-1), daily weight gain (0.022 ± 0.021 to 0.735 ± 0.026 g/d), survival rate (30.388 ± 1.734 to 86.333 ± 3.333%) and feed conversion rate (1.436 ± 0.023 to 2.185 ± 0.218) showed the lowest values in the highest stocking densities. The final biomass, specific growth rate, daily weight gain and survival rate recorded in D 1 tadpoles were significantly higher ( p ˂0.05) compared to the other lots. Thus the optimal stocking density is 5 tadpoles/L to ensure a good growth of H. occipitalis tadpoles in circular ponds.

Parachanna obscura is a fish that has a good economic value and is an important performance for aquaculture. By identifying the optimum stocking density and frequency of feeding, farmers can successfully decrease the feed charge and increase growth performance. The aim of our study is to define optimum frequency of feeding of P. obscura fingerlings reared controlled condition. Therefore the experiment was conducted during three months. The fingerlings of P. obscura were fed one of four schedules at 3% of body weight. The initial weight body was 13.27±0.07 g. At the end of this study, the results prove that survival rates were 100% and were not significantly affected by the frequency of feeding ( p ˃0.05). Growth performances varied significantly with treatments ( p

Artificial reproduction of fishes requires knowledge of their sexual dimorphism. African snakehead, Parachanna obscura , sexual dimorphism determination is difficult trough urogenital orifice examination. The aim of this study was to determine the sexual dimorphism of P. obscura using the parameters such as morphometric parameters, meristic parameters, weight-length relationship and condition factor. For the study, 30 specimens of P. obscura were collected from a swamp in Sakete a southeastern district of Benin. The fish weighed between 117 g and 251 g and their length were between 24.40 cm and 32.20 cm. At the end of this study, the different fins ray number were not significantly different (P>0.05). There was no significant difference among male and female fish (P>0.05) in total length, standard length, head length, snout length, snout width, head circumference and body circumference. Tail length had a significantly difference between male and female (P

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 (T 1 = 300 g/m 3 , T 2 = 600 g/m 3 , T 3 = 900 g/m 3 , T 4 = 1200 g/m 3 , T 5 = 1500 g/m 3 , T 0 = 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 T 1 , T 2 , T 3 , T 4 and T 5 . Optimal conditions of zooplankton production through phytoplankton are obtained with doses in T 2 and T 4 which present the best specific growth rate. The daily production through the highest phytoplankton biomass (chlorophyll-a) has been obtained with dose in T 5 . 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.

Lesser African threadfin (Galeoides decadactylus) is a nutritious marine fish, popular and widely used for drying-fermentation. The present work aims to evaluate the nutritional and microbiological quality of dried-fermented Lesser African Threadfin, currently used in food preparing in southern Benin. Four major sites of drying-fermentation fishes in southern Benin were investigated and dried-fermented Lesser African Threadfin was collected for quality control. Results indicated that the dried-fermented fishes were good sources of nutriments with a moisture content ranging from 44.62% ± 0.68% to 55.33% ± 0.23%. Proteins contents are ranged from 15.26% ± 0.32% to 22.95% ± 0.71%. All samples analyzed were rich in minerals such as magnesium, phosphorus, iron, with a higher content of calcium (1.23% ± 0.52% - 1.69% ± 0.38%). Statistical analyses showed significant difference (p 0.05) between samples analyzed. Microbiological analyses revealed that the total flora count of samples ranged from 1.4 × 102 to 8.0 × 104 ufc/g. The enumeration of total coliforms and fecal coliforms indicated that samples were contaminated with enteric bacteria. The spores of anaerobic sulfite reducer’s and Staphylococcus aureus counts were less than 10 cfu/g with an absence of Salmonella spp. Based on results from the present study, microbiological standards must be put in place during the process of dried-fermented fishes. Then, it’s advisable that relevant quality control unit should be reactivated to assess the quality of ready-to-eat food, and particularly the fermented fishes in other to protect consumer’s health.

Un releve parasitaire a ete realise en 2016 afin de mieux comprendre la presence, la repartition et la diversite de la faune parasitaire chez les especes piscicoles commerciales, Clarias gariepinus et Oreochromis niloticus provenant des whedos du delta superieur de l'Oueme au sud du Benin. L’echantillonnage a ete realise dans les trois communes du haut delta de l’Oueme (Bonou, Ouinhi, Zagnanado). Trente whedos artificiels ont ete selectionnes a raison de dix par commune. Un total de 757 poissons (417 C. gariepinus et 340 Oreochromis niloticus ) ont ete collectes durant les deux periodes de crue et de decrue du fleuve Oueme et ont ete examines pour des parasites en utilisant des techniques parasitologiques de routine. Onze (11) taxons parasites ont ete observes chez les deux especes hotes : 6 taxons sont presents chez Oreochromis niloticus et 7 chez Clarias gariepinus . Deux taxons, Clinostomum sp. et Gryporhynchidae, sont observes chez les deux especes hotes. La parasitofaune de O. niloticus est dominee par des taxons a transmission par stade libre, tandis que les parasites a transmission par stade libre et les parasites a transmission trophique sont egalement representes chez C. gariepinus . Les branchies sont tres faiblement parasitees, mais fortement par des monogenes. L'intestin est fortement parasite, principalement par les nematodes et les trematodes. En general, l'occurrence et la diversite des parasites chez ces especes de poissons mettent en evidence la probabilite d'une resurgence de pathologies dans les systemes aquacoles etudies. Ceci appelle a une sensibilisation des agriculteurs, des pisciculteurs, des fournisseurs de services et des chercheurs pour une meilleure gestion de la sante des poissons. © 2019 International Formulae Group. All rights reserved Mots cles: Metazoaires parasites, Clarias gariepinus , Oreochromis niloticus , Whedos, Sud Benin English Title: Metazoan parasite fauna of Clarias gariepinus (Clariidae) and Oreochromis niloticus (Cichlidae), two fishes from whedos around the upper delta of Oueme river in southern Benin English Abstract An intensive parasite survey was conducted in 2016 to get more information the occurrence of parasite fauna, its distribution and diversity in the commercial cultured fish species, Clarias gariepinus and Oreochromis niloticus , from whedos of Oueme upper delta in south Benin. Sampling was carried out in the three communes of the upper delta of Oueme (Bonou, Ouinhi, Zagnanado). Thirty artificial whedos were selected at the rate of ten per commune. A total of 757 fish (417 C. gariepinus and 340 O. niloticus) were collected during flood and recession periods of Oueme river and were examined for parasites using routine parasitological technics.The survey yielded 11 parasite taxon: 6 from Oreochromis niloticus and seven from Clarias gariepinus . Two taxon, Clinostomum sp. and Gryporhynchidae, were both parasites of the two fish hosts. O. niloticus was dominated by free-living stage-transmitted parasites, whereas both trophically and free-living stage-transmitted parasites were represented in C. gariepinus in relatively high intensities. Gills were generally less parasitized, but heavily by monogeneans. The gut was highly parasitized principally by nematodes and trematodes. Generally, the occurrence and diversity of parasites in these fish species highlight the likelihood of disease outbreak in the proposed aquaculture systems. This calls up to raise awareness in fish health management among potential farmers, service providers and researchers. © 2019 International Formulae Group. All rights reserved Keywords: Metazoan parasites, Clarias gariepinus , Oreochromis niloticus , Whedos, southern Benin

Two 90-day experiments were conducted in the same period in tanks and in earthen ponds to study the effects of culture systems on growth and fatty acid (FA) of Nile tilapia (Oreochromis niloticus L.) fingerlings (mean weight: 16.3 g) fed Azolla, as partial replacement for fish meal (FM). Diets were isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g-1) containing 0% (A0), 10% (A10), 20% (A20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM) respectively. Diet A0, without AM, acted as a control. In both experiments, fish growth decreased as AM level increased in diets (P P 30-A50). Interestingly, those fish were rich in eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). Consequently, the n-3/n-6 values decreased in tanks, whereas an increasing trend was found in ponds, and values were significantly higher in ponds than in tanks (0.35 - 0.53 vs. 0.08 - 0.17). The results suggest raising Nile tilapia with Azolladiets in ponds to improve growth and produce fish with a better FA composition, for the wellbeing of consumers.

The African bonytongue, Heterotis niloticus (Pisces: Osteoglossidae), is an omnivore foraging mainly on aquatic insects, microcrustacea, seeds and detritus. We examined the diet breadth and the trophic plasticity behavior of this species (1461 specimens) in the S? River and Lake Hlan water system located in the southern Benin (West Africa). Overall, the mean diet breadths of the two populations of Heterotis from both habitats were not significantly (p ≥ 0.05) different and were not associated with seasons. However, in Lake Hlan, mean diet breadths tended to increase with size (r = 0.81) and gut length (r = 0.82) indicating that bonytongues ingest a broader range of food resources as they grow. In both habitats, the positive correlation of both standard length (Log SL) and gut length (Log GL) with the volumetric proportions of detritus and with the volumetric proportions of seeds suggests that the consumption of these two food resources increased with the size of Heterotis and with the development of the digestive tract. Likewise, the negative correlation of both (Log SL) and (Log GL) with the volumetric proportions of aquatic insects and with the volumetric proportions of microcrustacea suggests that the consumption of these two food categories decreased as the size and the gut length of Heterotis increased. The differences in the consumption of microcrustacea (13.77% in Lake Hlan versus 2.63% in S? River) and mollusks (0.73% in Lake Hlan versus 4.91% in S? River) evidenced that Heterotis shifts his trophic structure according to resource availlability in the habitat. This foraging behavior suggests a degree of trophic plasticity in Heterotis. The specialized morphological structure of Heterotis, mainly the presence of a relatively high number of gill rakers (42 - 94 rakers on the first branchial arch) during its whole life, allowing sieving of zooplankton and other microcrustacea, and the presence of the gizzard favored this trophic plasticity. The broader diet breadth coupled with the trophic plasticity behavior is probably an advantage because it enables Heterotis not only to colonize and to adapt to unstable and changing aquatic habitats, but also to invade and to well-establish in various ecosystems, such as freshwater lakes, swamps, inundated plains, streams, rivers and fish farming ponds. As a result, the wider diet breadths and the trophic plasticity behavior depicted are useful eco-ethological tool for the conservation and the aquaculture development of H. niloticus.

Different pig dung doses were used to fertilize medium production of freshwater benthic macroinvertebrates in order to test the fertilization effect and determine the optimal dose. In fact, the experiment was carried out in triplicate, for 42 days in plastic buckets. These buckets were grouped in seven treatments (T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and T 7 ) which were fertilized (respective doses of 5%, 10%, 15%, 25%, 50%, 75% and 100% with pig dung in relation to the total substrate volume) and a control (T 0 ) which was not fertilized (0% of pig dung). Each bucket was seeded in benthic macroinvertebrates with an initial density of 9 individual/dm 3 (D 0 ). The results revealed that the utilization of pig dung improved the water chemical properties in the production medium as well as the macroinvertebrates density (p < 0.05). The optimal production of the latter was obtained with the dose of pig dung applied to treatment T 5 (50%), that is 150 g of dry dejections per dm 3 of substrate (150 g/dm 3 ) with a total average density of 742 ± 569 individual/dm 3 . The treatment T 5 (50%) constitutes then the dry pig dung optimal dose to be recommended for benthic macroinvertebrates production. © 2016 International Formulae Group. All rights reserved. Keywords: Fertilization, macroinvertebrates, optimal dose, pig dung, production

Objectif : L’objectif de la presente etude est d’evaluer la precision et l’exactitude des donnees sur les indicateurs des pecheries artisanales maritimes togolaises en vue de leur utilisation en connaissance de cause. Methodologie et resulta : La collecte et le traitement des donnees primaires sur les variables de ces pecheries (effort de peche, captures, CPUE, etc.) s’effectuent depuis 1999 suivant un programme d’enquetes utilisant un logiciel. Les deux elements sont connus sous le nom de "ARTFISH". Les donnees secondaires mensuelles de variabilite generees a l’aide d’ARTFISH (niveaux d’exactitude, coefficients de variation et coefficients d’activite pirogue) et stockees de 1999 a 2012 dans une base a la Direction des peches du Togo (DPA) sont extraites a 38,55% par echantillonnage et evaluees a partir des tests statistiques et de l’analyse en composantes principales (ACP). Les resultats obtenus montrent que les estimations de l’effort de peche et des captures sont respectivement exactes a 96,94% et 85,71% et precises a 95,92% et 57,14% et ; celles de la CPUE sont precises a 72,45%. Les forts coefficients de variation qui se situent entre 16,65 et 36,90% s’expliqueraient par l’heterogeneite observee souvent dans les debarquements des captures. Le coefficient d’activite pirogue variant de 29,53 a 70,09% depasse 100% de juillet a decembre surtout sur le site « Port de peche» et les pecheries de la senne tournante. Conclusion et application des resultats : Il est retenu que les estimations de l’effort de peche, des captures, de la CPUE, etc. des pecheries artisanales maritimes du Togo sont fiables au moins a 57,14% des echantillons. Toutefois, les forts coefficients de variation estimes a 42,86% des echantillons et attribuables a l’heterogeneite des debarquements des captures, montreraient la rarete des ressources halieutiques des eaux togolaises. Ainsi, les estimations des indicateurs des pecheries artisanales maritimes du Togo peuvent-elles etre utilisees sans trop de restrictions. Mots cles : Togo, pecheries artisanales maritimes, ARTFISH, estimations, donnees, precision, exactitude.

Parachanna obscura is the most common African Channidae. Various studies are being conducted on its biology and ecology. It lives in fresh water in quiet and muddy areas. It has accessory respiratory organs allowing it to live in hypoxic environment. It has a varied diet and feeds on fish, remains of fish, insects, other invertebrates and plant detritus. It is a species with iteroparous asynchronous oogenesis which breeds throughout the year but much more during and just after the flood. It size at first maturity is 24.5 cm. Eggs and larvae of P. obscura are yellow and guarded by one or both parents. Hardiness, rapid growth, high tasty flesh and commercial value of this species represent significant aquaculture potentiality. Natural stocks of P. obscura are overexploited and are not sufficient to met local demands. Its extensive farming system has already started in some African countries. Successful farming of this species in intensive systems and semi—intensive can help not only to preserve and enhance natural stocks of P. obscura but also to continuously produce fingerlings remediation technologies for direct human consumption.

The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.

This study is carried out to characterize the CHU-MEL effluents discharged into the Cotonou lagoon to assess the potential hazards of these releases for this ecosystem. To achieve this goal, the effluents collected at the end of the spillways have been analyzed. The results obtained from the physicochemical and microbiological analysis made it possible to assess the quality of the effluents. The pH, temperature and conductivity measured in-situ are, on average, 6.65, 30.3 °C and 763 μS/Cm. The average contents of dissolved oxygen, nitrite, nitrate, ammonium and Nitrogen Total Kjedhal (NTK) are respectively 1.92 mg/L, 0.06 mg/L, 7.75 mg/L, 18.45 mg/L and 28.78 mg/L. The Biochemical Oxygen Demand (BOD5) ranges from 38 mg/L to 53 mg/L, the Chemical Oxygen Demand (COD) from 97 mg/L to 274 mg/L, suspended solids (SS) belonging between 47 mg/L-398 mg/L and total phosphorus going from 0.37 mg/L to 13.02 mg/L. The microbiological parameters (total coliforms, faecal coliforms, E. coli , fecal streptococci and anaerobic sulphite reducers’ spores) are generally out of the standard values. These effluents present therefor risks for the fauna and the flora of the Cotonou’s lagoon and it is well indicated to assess them through ecotoxicity tests. © 2018 International Formulae Group. All rights reserved. Keywords: Hospital effluents, physicochemical parameters, microbiological parameters, pollution

Hoplobatrachus occipitalis is a frog belonging to Dicroglossidae family, the most spread in West Africa. This study aimed at performing to bibliographic synthesis on biology and ecology of this species in order to assess its potential in aquaculture. It lives along banks, rocky reservoirs and earthen ponds and prefers savannah areas. It feeds on coleopterans, caterpillars, spiders, vegetal fragments, fishes, crabs, ants, grasshoppers, locusts, dragonflies, frogs, mollusks, lizards, mice, butterflies, wasps and diptera larvae. The growth of H. occipitalis depend on the temperature and pH of the medium. A pH range 6.2 and 7 and temperature equal or upper, than 28 °C are suitable for its growth. H. occipitalis is an oviparous species. Its first sexual maturity height is 124.5 mm for females and 95 mm for males and it often reproduces during rainy season. The rapid growth, resistance and high nutritional quality of this species are some of its important potentialities for aquaculture. Natural reserves of H. occipitalis are overexploited and therefore no more able to satisfy the populations demand. A successful breeding of this species can help not only to preserve and strengthen the natural reserves but to produce regularly bulbous crowfoot for human consumption. Keywords : Hoplobatrachus occipitalis , biology, ecology, aquaculture potentialities.

Les systemes integres de production constituent l’une des voies essentielles pour une agriculture durable. Cette etude a pour but d’evaluer l’effet d’une alimentation a base de Azolla filiculoides , Elaeis guineensis , Ipomoea aquatica et Panicum maximum sur les performances zootechniques des lapins et le potentiel nutritif des crottes de lapins qui en resultent sur l’aquaculture. Pour ce faire, trente-six (36) lapereaux sevres de trois (3) semaines d’âge et pesant en moyenne 70,08 ± 0,04g chacun, ont ete utilises pour l’experimentation. Ces lapereaux ont ete repartis en quatre (4) lots de trois (3) lapereaux chacun, disposes dans des cages. Le lot 1 a recu l’aliment conventionnel VETO SA vendu sur le marche beninois (cet aliment est designe ici R 0 ), les lots 2, 3 et 4 ont recu respectivement un regime complete avec Ipomea aquatica R 1 (Ia), Elaeis guineensis (feuille) R 2 (Eg), et Panicum maximum R 3 (Pm). Des toiles de moustiquaires ont ete suspendues en dessous des cages pour recueillir les crottes. Les lapereaux nourris au regime complete 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 regime complete au Panicum maximum donne de bonnes performances zootechniques et constitue un atout economique pour les cuniculteurs. Les ratios N/P/K des crottes observes respectivement pour R 3 (Pm), R 2 (Eg), R 1 (Ia) et R 0 sont 18/2/1, 18/1/1, 8/1/1 et 7/1/1. Le meilleur ratio des macroelements fertilisants pour la production aquacole durable est celui obtenu avec le regime R 3 (Pm) (avec N/P = 15), mais le ratio N/P etait entre 10/1 et 20/1 pour les traitements R 0 , R 1 , et R 2 . © 2017 International Formulae Group. All rights reserved. Mots Cles: Performances zootechniques, crottes de lapin, macroelements fertilisants, aquaculture English Title: Feeding of rabbits ( Oryctolagus cuniculus L.) based on Azolla filiculoides , Elaeis guineensis , Ipomoea aquatica and Panicum maximum : Effect on rabbit growth and nutritive potential of the resulting rabbit dung for aquaculture English Abstract Integrated production systems are one of the essential pathways for sustainable agriculture. This study aims to evaluate the effects of feeding source based on Azolla filiculoides , Elaeis guineensis , Ipomoea aquatica et Panicum maximum on zootechnical performances of rabbit and the nutritive potential of the obtained rabbit manure on aquaculture. For this purpose, thirty-six (36) young rabbits of three (3) weeks old and weighing on average 70.08 ± 0.04g each, were used. They were shared into four (4) groups of three (3) rabbits each, placed in cages. Group 1 received the conventional food VETO SA sold on the Beninese market (this food is designated R 0 here), groups 2, 3 and 4 respectively received a diet supplemented with Ipomea aquatica R 1 (Ia), Elaeis guineensis (leaf) R 2 (Eg), and Panicum maximum R 3 (Pm). Mosquito nets were hung below the cages to collect the droppings (manures). Rabbits fed with the diet supplemented with Panicum maximum had an average daily gain of 76.19 ± 8.24 g/d against 61.90 ± 8.21 g/d for R 0 and R 2 (Eg) and 54.76 ± 14, 86 g/d for R 1 (Ia) per cage. The diet supplemented with Panicum maximum gives good zootechnical performances and constitutes an economic asset for rabbit farmers. N/P/K ratios of the observed droppings for R 3 (Pm), R 2 (Eg), R 1 (Ia) and R 0 are respectively 18/2/1, 18/1/1, 8/1/1 and 7/1/1. The best ratio of fertilizing macroelements for sustainable aquaculture production is that obtained with rabbit manures from the R 3 diet (Pm) (with N/P = 15), but the N/P ratio was between 10/1 and 20/1 for the R 0 treatments, R 1 and R 2 . © 2017 International Formulae Group. All rights reserved. Keywords: Zootechnical performance, rabbit droppings, fertilizing macroelements, aquaculture

In order to assess the effect of increasing levels of dietary soybean meal (SBM) or cottonseed meal (CSM) on growth and body mineral composition of juvenile African catfish, five isonitrogenous (39% crude protein) and isocaloric (13 kJ g, digestible energy) diets containing various levels of soybean meal (SBM30 and SBM60) or cottonseed meal (CSM30 and CSM60) as partial replacement of fish meal (Control) were fed to triplicate groups of 50 fish (initial mean weight: 10.3 g) in each tank (0.9 m). Over an 8-week feeding period, significant differences (P 0.05). However, fish fed SBM- or CSM-based diets have reduced Zn in the fillet than those fed the control diet (P

Two experiments were conducted in order to determine the appropriate age and stocking density of vundu catfish Heterobranchus longifilis at the weaning time. In the first experiment, five triplicate groups of 100 larvae (initial mean weight=3.4 mg) per aquaria were stocked from first feeding [day 3 post-hatch (p.h.)] to day 30 p.h., and then weaned, on days 3 (W3), 5 (W5), 8 (W8) and 14 (W14), and an unweaned group (An). Significant differences were observed in growth, survival, cannibalism, coefficient of weight variation and body composition among larvae weaned at different ages and the control group. The later the larvae were weaned, the better were the growth performances [final mean weight: from 65.1 to 201.1 mg and specific growth rate (SGR): from 11.0 to 15.2% day−1] and the survival (from 36.5% to 74.3%). The experiment with stocking densities of 5, 10, 25 and 50 larvae L−1 showed that increasing the stocking density decreased growth performances and weight variation but improved the survival rate of larvae. The best growth performances (SGR=13.4 and 11.4% day−1) with the lowest survival rates (70.3% and 77.3%) were observed in larvae stocked at densities of 5 and 10 larvae L−1 respectively.

The effects of the use of Azolla filiculoides Lam., as an alternative source of protein, on growth performances and production of Nile tilapia, Oreochromis niloticus, reared in wetland ponds was evaluated. Three isonitrogenous (27% CP) and isocaloric (4019.14 kcal/g) diets A0, A10, and A20 containing three levels of Azolla 0, 10, and 20, respectively, as a partial substitution of fish meal, were fed to three triplicate ponds of male O. niloticus (initial mean weight = 15.5 g). The Azolla-free diet (0% Azolla) served as a control. The growth performances and production are good in all treatments after 90 days of experiment. No significant differences among dietary treatment (P > 0.05) were noticed for daily growth rate (1.15 g/day-1.26 g/day), specific growth rate (2.27-2.35%/day), survival (74.78-77.43%), annual fish production (31.01-32.75 kg/are/year), and feed conversion ratio (1.06-1.13). Thus, similar growth and production performances were observed with fishes fed with A0 and those fed with A20. Therefore, up to 20% of Azolla in the ration of O. niloticus has no negative effect on either growth or production. The cost-benefit analysis showed a considerable reduction in the production costs of one kilogram of fish with increasing Azolla levels in diet, amounting to US$0.09 between A0 and A10 (P > 0.05) and US$0.14 between A0 and A20 (P

Two consecutive experiments were conducted to study the effects of stocking density on growth, food utilization, production and farming profitability of Nile tilapia (Oreochromis niloticus) fingerlings (initial mean weight: 16.2 ± 0.2 g) fed Azolla, as a main component in diet. In experiment 1, fish were hand-fed twice daily with three isonitrogenous (28.5% crude protein) and isocaloric (14.5 kJ g-1) diets A30, A35 and A40 containing 30%, 35% and 40% Azolla, respectively, for 90 days. Diets were formulated by mixing Azolla with locally available by-products. No significant differences were found in growth parameters and production (P>0.05). Total investment cost was significantly higher with A30 (P0.05). In experiment 2, three stocking densities, 1, 3 and 5 m-2, were assigned to three treatments T1, T2 and T3 respectively. Fish were hand-fed twice daily with diet A40. The final mean weight (89.53-115.12 g), the mean weight gain (0.81-1.10 g day-1), the specific growth rate (1.90-2.20% day -1) and the apparent food conversion ratio (1.29-1.58) were affected by stocking density, with significant difference (P-2, compared with the other densities. Stocking density did not affect survival rate (P>0.05). Yield and annual production increased with increasing stocking density, ranging from 7.10 ± 0.90 to 25.01 ± 1.84 kg are-1 and 28.79 ± 3.66 to 101.42 ± 7.48 kg are-1 year-1, respectively, with significant differences between all densities (P-2 produced the same profitability values. On the basis of growth values and economic return, it was concluded that Nile tilapia could be raised at a density of 3 fish m -2 with A40 to improve production and generate profit for nutritional security and poverty alleviation in rural areas. © 2007 Blackwell Publishing Ltd.

African catfish (Clarias gariepinus) (initial body weight: 34.8 ± 4.8 g) and vundu catfish (Heterobranchus longifilis) (initial body weight: 39.1 ± 8.2 g) fingerlings were stocked at densities of 4, 6 or 8 fish m in traditional fish ponds (whedos) constructed in the floodplain of the Oueme River (South Benin, West Africa), for 70 days from March to June 2005. Fish were fed twice a day with 34% crude protein feed formulated with locally available ingredients. The effects of stocking density were evaluated in growth responses, gross production and body composition. Water quality variables were similar (p > 0.05) in all compartments. Temperature and pH were at the optimum level for fish. Dissolved oxygen ranged from 0.9 to 1.2 mg l during the experiment and secchi disc transparency was low ( 0.05). These results are important because they indicate that, as far as growth rate and production are concerned, African catfish is more profitable than vundu catfish for culture at high density in whedo.

La presente etude s’est interessee a la comparaison des performances zootechniques et economiques des porcs nourris avec des aliments commerciaux et des aliments non conventionnels. Au total, 90 porcelets metis (race locale X Large white) âges de 60 a 90 jours dont 45 mâles castres et 45 femelles, ont ete repartis en 15 lots de 6 animaux, a raison de 3 loges de 6 porcelets par traitement alimentaire. Chaque lot a ete nourri a volonte avec un aliment commercial et quatre aliments contenant differents taux de Azolla, Moringa, son de riz, visceres de poulet Cobb 500 et de poisson Oreochromis niloticus . Une difference significative (P < 0,05) a ete notee entre les gains moyens quotidiens (GMQ). Apres 90 jours d’experimentation, les GMQ etaient de 197g/j pour les porcs du lot a aliment commercial et de 63 a 101g/j pour ceux soumis aux aliments a base de ressources non conventionnelles. Il ressort des calculs economiques que le cout alimentaire (Ca) par kg de gain de poids (GP) etait plus faible pour l’aliment non conventionnel (716 FCFA/kg GP) par rapport a l’aliment commercial (830 FCFA/kg GP). Il est donc possible d’utiliser ces ressources non conventionnelles pour nourrir de facon efficiente des porcs dans un systeme integre d’exploitations familiales tout en rendant l’environnement sain. © 2015 International Formulae Group. All rights reserved. Mots cles: Aliment, performance, porcs, rentabilite economique English Abstract The present study was focused on the comparison of zootechnic and economic performance of pigs nourished with commercial and non-conventional feed. In total, 90 crossbred piglets (Landrace x Large white) aged 60 to 90 days with 45 castrated males and 45 females, were divided into 15 groups of 6 animals at the rate of 3 lodges of 6 piglets per treatment. Each batch was fed ad libitum with commercial feed and four feed containing different levels of Azolla, Moringa, rice bran, chicken Cobb 500 and fish Oreochromis niloticus viscera. A significant difference (P < 0.05) was observed between Average Daily Gain (ADG). After 90 days of experimentation, the ADG were 197 g / day for pigs nourished with commercial feed and 63 to 101 g / day for those subjected to feed made from unconventional resources. It emerges from the economic calculations that the feed cost (Ca) per kg of Weight Gain (WG) was lower for non-conventional feed (716 FCFA / kg WG) than the commercial feed one (830 FCFA / kg WG). It is therefore possible to use these unconventional resources efficiently to feed pigs in an integrated system of family farms while making healthy environment. © 2015 International Formulae Group. All rights reserved. Keywords: Feed, performance, pigs, economic profitability

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).

L’effet de la fertilisation a base des dejections de porc sur la production du zooplancton a ete teste dans des seaux en plastique pendant 21 jours. Les milieux fertilises (T1) et temoins (T0) sont ensemences en phytoplancton puis en zooplancton (52 ind/l). L’echantillonnage du zooplancton est fait tous les sept (07) jours. De meme, les parametres physico-chimiques et trophique (chlorophylle a) ont ete estimes. Les resultats ont montre que les dejections de porc ameliorent les proprietes chimiques (nitrite, nitrate, phosphate) et planctoniques des milieux de production (p < 0,05). Ainsi, les milieux fertilises donnent la meilleure densite maximale zooplanctonique (1071 ind/l) par rapport aux milieux temoins (145 ind/l). La dynamique des peuplements zooplanctoniques indique la dominance des copepodes qui sont les predateurs des rotiferes et des cladoceres. Mots cles : Dejections de porc, fertilisation, production du zooplancton, seau en plastique.

– Population structure of the African bonytongue, Heterotis niloticus, was examined in southern Benin within Lake Hlan and a region of the So River floodplain located approximately 60 km downstream from the lake. Both locations support important fisheries in which Heterotis is the principal target species during the flood period. Ripe adults comprised over 40% of the population in Lake Hlan, whereas only 3.5% of individuals captured from river sites were adults. Monthly averages for the gonadosomatic index and percentages of individuals with mature gonads peaked as water levels increased during the wet season then declined during the peak flood period. Oocyte size frequency distributions from ovaries suggested a potential to produce an additional cohort in the event of nesting disruption. During the peak spawning period (May to August), between 37 and 51 active nests per hectare per month were observed in Lake Hlan. The number of larvae per nest ranged from 3953 to 6125. Lake Hlan bonytongues appear to constitute an important source subpopulation that exports new recruits to river/floodplain areas downstream where intense fisheries harvest mostly juveniles and subadults. Consequently, restriction of harvest of adult bonytongues in Lake Hlan may be essential for sustenance of commercial fishing in downstream reaches of the So River. Resumen 1. La estructura poblacional del osteoglosido africano, Heterotis niloticus, fue estudiada en el Lago Hlan (sudeste de Benin), y en un area de la zona de inundacion del Rio So, localizada a unos 60 Km. del lago, aguas abajo. Ambas localidades mantienen importantes pesquerias, en las cuales H. niloticus es una de las especies mas importantes durante el periodo de inundacion. 2. Los adultos maduros constituyen >40% de la poblacion del Lago Hlan, pero solo el 3.5% de los individuos capturados en el rio fueron adultos. Los promedios mensuales del indice gonado-somatico y los porcentajes de individuos con gonadas maduras aumentaron al incrementar el nivel de las aguas durante el periodo de lluvias, y disminuyeron posteriormente durante el pico del periodo de inundacion. La distribucion de frecuencias de tamanos de los oocitos en los ovarios, sugirio la posibilidad de producir una cohorte adicional en el caso en que halla perturbaciones durante la puesta. Entre 37 a 51 nidos activos por hectarea fueron observados en el Lago Hlan durante el pico de desove (Mayo-Agosto). El numero de larvas por nido vario en el rango 3.953–6.125. 3. Los osteoglosidos del Lago Hlan parecen constituir una importante sub-poblacion ‘fuente’ que exporta nuevos reclutas a las areas bajas del rio y zonas de inundacion donde la intensa actividad pesquera explota principalmente juveniles y sub-adultos. Consecuentemente, restricciones a la cosecha de osteoglosidos adultos en el Lago Hlan puede ser esencial para una pesca comercial sostenible en la parte baja del Rio So.

The African bonytongue, Heterotis niloticus (Osteoglossidae), is an important fisheries and aquaculture species in West Africa. This species has frequently been characterized either as an omnivore, insectivore or detritivore, the latter, in part, because of its benthic feeding habitats and possession of a gizzard (thick-walled pyloric stomach). We examined diets of two populations of H. niloticus in the So River in southern Benin. A population from the river channel and seasonally flooded marginal plains was dominated by juvenile and subadult size classes. Adults size classes were common in a second population from Lake Hlan, a natural lake in the river floodplain located upstream from the channel study region. Heterotis of all sizes consumed a variety of food resources, ranging from aquatic invertebrates to small seeds. Aquatic invertebrates composed a large proportion of the diets of juveniles, and adults consumed a mixture of aquatic invertebrates, seeds, and detritus. Seasonal dietary variation was observed in both populations, and diet breadth was not significantly different between populations. Aquatic invertebrates remained significant in diets of larger size classes; diets of fish between 100 and 200 mm began to include seeds and detritus, with a marked increase in the volumetric proportion of detritus in diets of fish between 300 and 400 mm in Lake Hlan and between 500 600 mm in the river. Relative gut length was inversely related to body size, which supports the notion that Heterotis is an omnivore and not a specialized detritivore. The thick-walled gizzard of Heterotis, which generally contained sand, probably aids digestion of seed coats. Because Heterotis consume mostly invertebrates and grass seeds in shallow waters of seasonal aquatic habitats and lakes the river floodplain, foraging success and fishery production should be strongly dependent on the annual flood pulse.

Four feeding experiments were conducted to estimate the optimal daily food ration of Eurasian perch at different stages of its development under optimum rearing temperature (23 °C). Mean initial weights of 0.22-, 0.73-, 1.56- and 18.9-g fish, previously habituated to a dry diet, were used in experiments lasting between 14 and 30 days, depending on initial body weight. Daily feeding levels ranged from 2% to 20% of biomass in 0.22-g fish, from 1% to 8% in 0.73-g fish, from 1% to 10% of biomass in 1.56-g fish and from 0.3% to 3% of biomass for 18.9-g fish. Feeding levels significantly affected survival of perch, except in experiment 4 with large juveniles (18.9). In experiments 2 and 3 (with 0.73- and 1.56-g fish, respectively), cannibalism was significantly higher at the lowest feeding level (1% biomass day−1), while starvation seemed to be the major cause of death in experiment 1 with 0.22-g fish. Values of specific growth rate (SGR) plotted against daily food ration allowed the maintenance, optimum and maximum feeding levels to be determined, according to the Brett and Grove's model. Optimum feeding level for Eurasian perch decreased from 7.4% to 5.1%, 4.5% and 2.2% biomass day−1 for fish of 0.22, 0.73, 1.56 and 18.9 g initial body weight, respectively.

In order to eliminate use of fishmeal in aquafeeds, we evaluated the effect of total replacement of fish meal by a mixture of earthworm (Eisenia foetida) and aquatic fern Azolla filiculoides in the diets of Nile tilapia Oreochromis niloticus (Linnaeus, 1758). The experiment was conducted in O. niloticus fingerlings (initial mean weight = 5.6±0.2 g) for a period of 60 days. Five experimental diets isoproteic (30.4±0.6% protein) comprising control diet A0 and four test diets (A1 to A4) without fish meal were formulated. To satisfy essential amino acids requirements in test diets, the ratios 2:1; 1:1; 1:2; 1:5 between A. filiculoides and earthworm meals were used respectively in total replacement of fish meal. The diets were tested in triplicate. On termination of the experiment, the final mean weights in the test diets (10.79 to 11.94 g) were lower than 14.9 g obtained in group fed control diet (p

La presente etude a ete conduite pour apprecier le niveau de pollution des eaux du collecteur de Dantokpa (Cotonou-Benin) par l’evaluation de la diversite phytoplanctonique en relation avec les caracteristiques physico-chimiques afin de faire ressortir le risque de leur rejet sans traitement dans la lagune de Cotonou. L’analyse des eaux usees prelevees au niveau de trois stations a revele des teneurs elevees en orthophosphates et en mineraux azotes (ammonium, nitrate et nitrite), une forte conductivite electrique et un faible taux d’oxygene dissous. Au total, 39 especes phytoplanctoniques ont ete identifiees au microscope et sur la base des cles d’identification. Cette communaute heterogene de phytoplancton se repartit dans 5 embranchements (Chlorophytes, Chrysophytes, Cyanophytes, Euglenophytes et Rhodophytes) et 9 classes dominees par les Cyanophycees et les Diatomophycees. La densite phytoplanctonique a ete elevee avec une moyenne de 25760 cellules/ml. Les parametres etudies temoignent de l’abondance de l’azote, du phosphore et des matieres organiques dans les eaux du collecteur. Il est donc necessaire de les epurer avant leur deversement dans la lagune au risque de provoquer son eutrophisation. Mots cles : phytoplancton, eaux usees, epuration, eutrophisation, Cotonou.

Effects of increasing dietary protein on growth parameters, feed utilization were studied in Parachanna obscura larvae with initial body weight 0.12 ± 0.01 g. The experiment was conducted during 28 days in re-circulating system composed of 15 tanks containing 20 L of water each. 50 larvae were stocked per tank. Five semi - purified isoenergetic experimental diets were formulated with different protein level (35, 45, 50, 55 and 60 g/100 g of diet). Each diet was tested in triplicate. Growth parameters and feed utilization were significantly influenced by dietary protein (P 0.05). Second degree polynomial regression and broken line models were used to analyze the relationships between dietary crude protein and SGR. Based on the results of this study, protein requirements of P. obscura larvae ranged from 45 and 55.5% of the diet.