In developing countries, advanced aquaculture techniques are still at the embryonic stage. This study was carried out from January to December 2021 in the ponds of the West Cameroon Region and at the Ichthyology and Applied Hydrobiology Research Unit of the University of Dschang with the aim of contributing to a better understanding of species richness and distribution of phytoplankton populations in fertilised ponds. For this purpose, a total of fifteen (15) ponds including 03 in Bamendou (fertilised with cow dung), four in Batié (two fertilised with pig manure and two with wheat bran), one in Dschang (fertilised with chicken manure), four in Fokoué (two fertilised with pig manure and two unfertilised), and three in Foumbot (fertilised with cow dung), were assessed. These ponds were chosen based on the availability of fish farmers and the type of fertiliser administered. Together with water physicochemical properties measurement, phytoplankton sampling was done between 6 a.m. and 8 a.m. on a monthly basis. The results showed that phytoplankton species and genera richness was higher in unfertilised ponds in Fokoué ponds and in animal feed enriched ponds in Batié, respectively. However, the highest family richness was obtained in Dschang receiving chicken manure with a percentage of 88.8% of the total family richness. The species Microcystis aeroginosa exhibited the highest species frequency (57%) out of all the species recorded in the ponds of Batié fertilised with pig manure. The lowest Shannon-Weaver diversity indices and Piélou evenness indices were recorded in the Fokoué ponds independent of the type of fertiliser, and in the Dschang ponds receiving chicken manure. The outputs of this work are better proposals for the production of phytophagous or bulldozer fish, such as carp, in relation to the site and the type of fertilisers in the Western highlands agroecological zone of Cameroon in particular and the world in general.

The aim of this study was to contribute to the improvement of knowledge on the growth of endogenous catfish of Cameroon Clarias jaensis to develop the standards of his breeding. For this purpose, 396 fingerlings (36.7 ± 10.1 g) were divided into four comparable group with three replications. Four experimental rations containing 3000, 3100, 3200 and 3300 Kcal/kg of metabolize energy were distributed in these group at 5% of ichtyobiomasse. Except the feed intake and survival rate, other growth characteristics were comparable (P>0.05) between rations. The higher feed intake and the lowest consumption index were recorded with the ration containing 3000 Kcal/kg. The weight (95.10 ± 8.14 g), total length (23.77 ± 1.15 cm), weight gain (58.70 ± 9.49g), average daily gain (1.01 ± 0.16 g), specific growth rate (1.66 ± 0.26%) and K factor (0.71 ± 0.05) were higher with the ration containing the lowest level of energy. This reveals that Clarias jaensis fingerlings requires less energy for growth compared to other catfish like Clarias gariepinus. In view of the above and given the cost of manufacturing the food, the ration containing 3000 kcal/kg would be agro economically sustainable although the search for the optimal level of energy remains.

The aim was to contribute to the valorization of the alternative sources of animal protein. More specifically, it was question to evaluate the effect of substitution of the fish meal by the maggot meal on the survival, growth performances and food production cost of Clarias jaensis. To this end, 120 fingerlings were divided in four groups (T0, T1, T2 and T3) repeated 3 times and receiving 0, 50, 75 and 100% of maggot meal. The fish were fed to 5% of ichtyo biomass for 3 months. The treatments did not have any significant effect on survival, FC, SL, LW, WG, ADG and SGR (P>0.05). However, the values of the LW (145.12±20.72), WG (104.12±20.72g), ADG (1.16±0.23g) and SGR (1.39±0.14) were higher with T2. The CI (1.46±0.04) of this same treatment were weaker and the condition factor K (1.19±0.22) was higher as compared to other treatment (P<0.05). However, the lowest value of the cost of feed consumption and feed production was recorded with the T2 ration (75% of maggots meal) and highest with the control ration T0 (0% of maggots meal) (P<0.05). This study revealed that incorporation of the maggot meal in feed increases the growth performances of Clarias jaensis fingerlings.

Objectif : La pisciculture en étang se caractérise par une grande diversité de pratiques piscicoles des plus extensives aux plus intensives en passant par la pratique semi-intensive basée sur la fertilisation. Ainsi, le présent travail portant sur la culture du phytoplancton a été initié en vue de contribuer à l’amélioration de la production de poisson en étangs fertilisés à travers une meilleure gestion des fertilisants. Méthodologie et résultats : L’essai a été conduit dans 9 étangs en dérivation de même superficie (5,7 x 5,7 m) et de profondeur 1 m à la station aquacole de la Ferme d’Application et de Recherche (F.A.R) de l’Université de Dschang. Un filet de 1,5 mm d’ouverture de maille a été fixé sur le tuyau d’alimentation de chaque étang en vue d’éviter l’intrusion des poissons venant de la retenue. Chacun des traitements constitués de 0 ; 800 et 1000 kg/ha de lisier a été appliqué dans 3 étangs de façon aléatoire. Les résultats ont montré que la richesse des espèces ainsi que des genres phytoplanctoniques a diminué avec l’apport du lisier, soit la valeur 164 espèces enregistrées dans les étangs non fertilisés contre 124 dans le traitement à la dose de 800 kg/ha de lisier. Les Cyanophytes et Bacillariophytes ont été le plus abondant dans les étangs non fertilisés alors que les Euglenophytes et les Pyrrophytes ont été dominant dans les étangs fertilisés à la dose de 1000 kg. La densité phytoplanctonique a augmenté avec l’accroissement de la quantité de lisier en étang. Conclusion et application : La dose de lisier de porc a influencé significativement la richesse et la densité phytoplanctonique en étang. En somme la dose 1000kg peut déjà être utilisée sous réserve de rechercher la dose optimale de production phytoplanctonique en étang au regard de l’évolution progressive de la densité phytoplanctonique avec l’augmentation de la dose. Ces données vont permettre à améliorer l’élevage des espèces de poisson phytophage notamment les carpes en étang. Mots clés : Fertilisation, lisier de porc, taxon, phytoplancton. Nana et al., J. Appl. Biosci. 2020 Effet comparé de la dose de lisier de porc utilisé comme fertilisant en étang sur la richesse et la distribution des taxons phytoplanctoniques 15631 Comparative effect of the dose of pig manure used as pond fertilizer on the richness and distribution of phytoplankton taxa ABSTRACT Objective : Pond pisciculture is characterized by a wide variety of fish farming practices, from the most extensive to the most intensive, including semi-intensive practices based on fertilization. Thus, the present work on phytoplankton culture was initiated to contribute to the improvement of fish production in fertilized ponds through better fertilizer management. Methodology and results: The trial was conducted in 9 diversion ponds of the same area (5.7 x 5.7 m) and depth 1 m at the aquaculture station of the Ferme d'Application et de Recherche (F.A.R) of the University of Dschang. A 1.5 mm mesh size net was attached to the inlet pipe of each pond to prevent fish intrusion from the reservoir. Each of the treatments consisting of 0 ; 800 and 1000 kg/ha of manure was applied in 3 ponds at random. The results showed that the species and genus richness of phytoplankton decreased with manure application, with 164 species recorded in the unfertilized ponds compared to 124 in the 800 kg/ha manure treatment. Cyanophytes and Bacillariophytes were most abundant in unfertilized ponds while Euglenophytes and Pyrrophytes were dominant in ponds fertilized at the 1000 kg rate. Phytoplankton density increased with increasing amount of manure in the pond. Conclusion and application : The rate of pig manure significantly influenced the phytoplankton richness and density in the pond. In sum, the 1000kg rate can already be used if the optimal rate of phytoplankton production in ponds is sought in view of the progressive evolution of phytoplankton density with increasing rate. These results should contribute to the production of phytophagous fish, in particular the Carp in pond. Keywords : Fertilization, pig manure, taxon, phytoplankton.

In order to contribute to the improvement of aquaculture production, reproductive parameters of three populations of Oreochromis niloticus of Cameroon were studied between March and May 2019 at the research station of Foumban. At this effect, a total of 81 parents (27 males and 51 females with respective weight 124 ± 6g and 144 ± 5​​g) coming from three hydrogeographicals origins (Niger, Sanaga and IRAD Station) were randomly distributed in triplicate in nine concrete tanks of a m² each with a sex ratio of one male for two females (1♂/2♀). Throughout the test, six females carrying eggs in the oral cavity were collected in each population and 45 days after the start of the trial, all the offspring were collected and the adults sacrificed. At the end of experiment, the IRAD population presented highest significant values (p ≤ 0.05) regardless of the performances considered. The values of the gonado-somatic and the gonado-metric characteristics significantly lower (p ≤ 0.05) were obtained in Niger population (GSR = 0.04 ± 0.02, GSI = 0.05 ± 0.03 and GMR=0.19 ± 0.08;GMI= 0.24±0.07). Considering sex, males presented the lowest significant values (p ≤ 0.05) for all the characteristics studied (GSR = 0.04±0.01, GSI = 0.04±0.01 and GMR= 0.23±0.08;GMI= 0.29±0.09).