Effet de l’aliment artificiel et du zooplancton sur la flore intestinale bactérienne chez la carpe (Cyprinus carpio)

La digestion et l’absorption des aliments chez le poisson sont facilitées tout au long de son tractus digestif par des sécrétions de substances et l’activité des micro-organismes contenus dans son tube digestif. Cyprinus carpio en particulier entretient des relations avec sa flore bactérienne intestinale dont la composition peut être influencée par le type d’aliment ingéré. A cet effet, un essai été mené de Mars à Juin 2020 à la station aquacole de l’Université de Dschang avec pour objectif général de contribuer à l’amélioration de la production piscicole à travers une meilleure connaissance de l’effet de l’aliment sur la flore bactérienne intestinale de Cyprinus carpio. Il a été effectué sur un effectif de 405 carpes communes nourris au zooplancton et à l’aliment artificiel. Des échantillons du contenu de l’intestin ont été prélevés sur 54 poissons et ont été soumis à des cultures bactériennes pour l’identification des genres de bactéries. Les résultats relatifs à l’identification des Firmicutes et Protéobactéries présents dans l’intestin des poissons en fonction du type d’aliment montrent que sept genres de bactéries à savoir Lactobacillus, Staphylococcus, Streptococcus (Firmicutes), Salmonella, Shigella, Klebsiella et Escherichia (protéobactéries) ont été présents. En ce qui concerne l’évaluation des effets du type d’aliment sur l’état de bactéries utiles et pathogènes de la flore intestinale les résultats montrent que quatre étaient pathogènes (Staphylococcus, Streptococcus, Salmonella, Shigella) et trois étaient utiles (Klebsiella, Escherichia et Lactobacillus) pour les poissons. Les résultats relatifs aux abondances des genres de bactérie montrent que les genres Lactobacillus, Klebsiella, Streptococcus et Salmonella sont plus abondants dans l’intestin des carpes qui ont été nourri au zooplancton et à l’association zooplancton et aliment artificiel. Des abondances relatives identiques de 27,78% ont été obtenues pour les genres Staphylococcus, Shigella, Escherichia et Streptococcus dans l’intestin des carpes ayant reçu l’aliment artificiel uniquement. Elles sont supérieures à celles des poissons qui ont reçu le zooplancton uniquement. Les tests de la corrélation effectués entre les caractéristiques de croissances et les caractéristiques de la microflore intestinale de la carpe commune ont révélés que le gain moyen quotidien (0,19 g/j), le gain de poids (2,60 g) et le taux de croissance spécifique (1,94%), sont plus élevées chez les poissons qui ont reçu l’aliment artificiel associé au zooplancton et les plus faible chez ceux qui ont reçu l’aliment artificiel uniquement respectivement pour des valeurs de 0,17 g/j ; 2,44 g et 1,87%. Les bactéries du genre Shigella chez les carpes nourris uniquement au zooplancton ont eu des effets statiquement significatifs sur leur gain de poids et leur gain moyen quotidien. Il ressort de cette étude que le type d’aliment influence la composition bactérienne dans l’intestin des carpes et par conséquent sa croissance. Au vue de ces résultats, il est idéal d’utiliser le zooplancton dans l’aliment pour poisson

Life cycle assessment of Co-culture of Clarias gariepinus and Oreochromis niloticus in the whedos of Ouémé delta in Benin

The development of the fish farming with regard to environmental sustainability is nowadays a serious alternative to satisfy the needs of the population in quality animal protein and to reduce imports in Benin. In this study we assessed the environmental impacts of co-culture of Clarias gariepinus and Oreochromis niloticus systems in the whedos of Ouémé delta in Benin. Life Cycle Analysis (LCA) which is a systemic method that assesses all potential environmental impacts of global and regional product, service, company or process has been used according to the CML baseline 2000 method. However, that method was adapted for fish farming system. The estimation of nitrogen (N) and phosphorus (P) wastes in production systems (T1: imported feed, T2: local feed and T3: mixed feed), was performed according to the nutritional balance method; and calculation of impact categories was conducted with environmental analysis software, SimaPro ® 8.0.5.13.  For all the environmental impact category considered (non-renewable energy, climate change, eutrophication, freshwater ecotoxicity, terrestrial ecotoxicity and potential acidification), the T1 system recorded the lowest values of impacts compared to T2 and T3. Except the eutrophication dominated by the production process, the feed production process is the major contributor of other impact categories. To optimize fish productivity and sustainability of fish farming, the T1 system would be advisable. Keywords: Life Cycle Assessment, happa, Ouémé, fish farming, whedo

Effect of the Incorporation Level of Ripe Avocado Pulp Powder Persea americana on the Zootechnical Performances of Clarias jaensis Juveniles (Boulanger, 1909)

In order to contribute to the valorization of agricultural by-products in fish feed, the effect of the incorporation level of the ripe avocado pulp powder persea americana on the zootechnical performance of Clarias jaensis Juveniles (Boulanger, 1909), was studied between February and July 2019 in the highland zone of West Cameroon. To attend the aims, 156 juvenile Clarias jaensis (25.82 ± 7.43g) settled in triplicates in floating tanks were fed four iso-protein rations (40% crude protein) corresponding to 0, 8, 12 and 16% incorporation of ripe avocado. Feed were distributed twice daily (8 am and 6 pm) at 5% of the fish biomass for 63 days. The following results were as follows: Survival rate, final mean weight, daily mean weight gain, specific growth rate and condition factor K were higher and non-significant in batches receiving 8% of ripe avocado pulp powder with a lower feed conversion ratio (99,14 ± 0,50% ; 40,22 ± 10,5g; 0,14 ± 0,44 g/d, 0,41 ± 1,07 %g/d; 0,70 ± 0,09 %g/cm3 and 1,87 ± 0,09) and lower with a highest feed conversion ratio at 16% incorporation (93,67 ± 8,47 %; 30,02 ± 8,00g; 0,08 ± 0,22 g/d; 0,28 ± 0,77 % g /d; 0,68 ± 0,15 %g/cm3 and 2,018 ± 017). Body composition varied with the level of pulp meal incorporation, water content was high with 0% (79.14%), and dry matter (23.87%), crude protein (15.35%) and fat (5.23%). It was higher with 16%, while ash was higher (3.45%) in batches fed with 12% incorporation. The feed cost was lower at 8% incorporation (734.89Fcfa/kg of fish produced). The incorporation of 8% avocado pulp meal was found to improve the growth of Clarias jaensis juveniles and reduce the feed cost. Producers can use spoiled avocados as fish feed to reduce production costs, without negative impact on the final product

Performances de reproduction du poisson chat endogène du Cameroun Clarias jaensis (Boulenger, 1909) en milieu contrôlé

Les performances de reproduction de Clarias jaensis ont été évaluées entre mai et octobre 2014 à Batié (Ouest-Cameroun). A cet effet, 30 femelles de poids moyen 199, 52 ± 34,85 g ont été réparties en 5 lots comparables. Chaque lot choisi au hasard a été soumis à l’Hormone Chorionique Gonadotrophine (HCG) aux doses de 3500, 4000 et 4500 Unités Internationales (UI) / kg et aux extraits hypophysaires des mâles et des femelles. Le poids et le diamètre des ovocytes, les taux de fécondation et d’éclosion ont été évalués. Les principaux résultats ont montré que: le poids des ovocytes a été le plus élevé (p < 0, 05) avec l’extrait hypophysaire femelle (39,33±17,08g) ; le diamètre des ovocytes a été comparable entre les traitements. Le taux de fécondation a été le plus élevé pour la dose de 4000 UI / kg de HCG (87, 50 ± 12,45%) suivi de l’extrait hypophysaire femelle (85,08 ± 14,29%). Cependant aucune différence significative (p ˃ 0,05) n’a été obtenue. Le taux d’éclosion a été plus élevé avec l’extrait hypophysaire femelle (19, 38 ± 6,58%). La reproduction artificielle chez Clarias jaensis est possible avec l’hormone HCG à 4000 UI / kg ou des extraits hypophysaires femelles.© 2016 International Formulae Group. All rights reserved.Mots clés: Clarias jaensis, espèce endogène, performances de reproduction, captivité, CamerounEnglish Title:  Reproductive performances of indigenous catfish of Cameroon Clarias jaensis (Boulenger, 1909) in captivityEnglish AbstractIn order to improve local biodiversity and number of fishes in aquaculture in Cameroon, reproductive performances in captivity of Clarias jaensis have been studied between Mai and October 2014 in Batié (West Cameroon). In fact, 30 females with 199, 52 ± 34, 85 g were divided randomly into five comparable treatments. Each was submitted to a Human Chorionic Gonatropin Hormon at 3500, 4000 and 4500 Internationals Units (UI) / kg of body weight, males and female’s pituitary extracts. The main results obtained were: The oocyte weight was significantly higher (p < 0, 05) with females’ pituitary extracts (39, 33 ± 17,08g), the oocyte diameter mean was comparable within the treatments. The higher fecundity rate was obtained with the Human Chorionic Gonadotropin Hormon at 4000 UI / kg of body weight (85, 08 ± 14, 29%). However, no significant differences (p ˃ 0, 05) were found. The hatching rate was significantly higher (p < 0, 05) with the pituitary extracts of females (19, 38 ± 6, 58%). Clarias jaensis can be reproduced artificially using Human Chorionic Gonadotropin Hormon at 4000 UI / kg of body weight or female’s pituitary extracts.© 2016 International Formulae Group. All rights reserved.Keywords: Clarias jaensis, reproductive performances, indigenous species, captivity, Cameroo

ESTIMATION TEST OF GASEOUS EMISSIONS FROM FISHPONDS WITH CONTRASTED INPUTS

Daily operations in fishponds induce gas emissions, mainly of carbon dioxide (CO2 ), oxygen (O2 ), ammonia (NH3 ), methane (CH4 ), nitrous oxide (N2O) and nitrogen (N2 ). Estimating the effect of management practices on ammonia and greenhouse gas emissions is a new challenge for the sustainable development of fish farming and increased productivity of fishponds. Experiments were performed on eight fishponds at the aquaculture experimental platform of the University of Dschang, Cameroon. Gases were collected using a small static chamber floating on the pond surface for 24 hours. Results show that CO2 gradients related to fish densities in the fishponds and to organic inputs. CH4 emissions measured in the ponds related to higher oxygen levels in the water due to higher photosynthesis and a large deposit of dead plankton on the bottom. NH3 and N2O gradients were significantly correlated, while no correlation was detected between NH3 and CO2 . It is assumed that higher N input (urea) or higher fish population (higher N exc retion) induced higher NH 3 emissions and higher N turn-over, inducing limited N2O emissions and nitrite accumulation below toxic levels. Further work in cont rolled conditions could provide more reliable emission measurements and confirm the observed trend

Life cycle assessment of integrated fish pond aquaculture of household farms in sub-Saharan Africa

National audienc

Effect of the Incorporation Level of Ripe Avocado Pulp Powder Persea americana on the Zootechnical Performances of Clarias jaensis Juveniles (Boulanger, 1909)

<p>In order to contribute to the valorization of agricultural by-products in fish feed, the effect of the incorporation level of the ripe avocado pulp powder <i>persea americana </i>on the zootechnical performance of <i>Clarias jaensis </i>Juveniles (Boulanger, 1909), was studied between February and July 2019 in the highland zone of West Cameroon. To attend the aims, 156 juvenile <i>Clarias jaensis (</i>25.82 ± 7.43g) settled in triplicates in floating tanks were fed four iso-protein rations (40% crude protein) corresponding to 0, 8, 12 and 16% incorporation of ripe avocado<i>. </i>Feed were distributed twice daily (8 am and 6 pm) at 5% of the fish biomass for 63 days. The following results were as follows: Survival rate, final mean weight, daily mean weight gain, specific growth rate and condition factor K were higher and non-significant in batches receiving 8% of ripe avocado pulp powder with a lower feed conversion ratio (99,14 ± 0,50% ; 40,22 ± 10,5g; 0,14 ± 0,44 g/d, 0,41 ± 1,07 %g/d; 0,70 ± 0,09 %g/cm3 and 1,87 ± 0,09) and lower with a highest feed conversion ratio at 16% incorporation (93,67 ± 8,47 %; 30,02 ± 8,00g; 0,08 ± 0,22 g/d; 0,28 ± 0,77 % g /d; 0,68 ± 0,15 %g/cm3 and 2,018 ± 017). Body composition varied with the level of pulp meal incorporation, water content was high with 0% (79.14%), and dry matter (23.87%), crude protein (15.35%) and fat (5.23%). It was higher with 16%, while ash was higher (3.45%) in batches fed with 12% incorporation. The feed cost was lower at 8% incorporation (734.89Fcfa/kg of fish produced). The incorporation of 8% avocado pulp meal was found to improve the growth of <i>Clarias jaensis </i>juveniles and reduce the feed cost. Producers can use spoiled avocados as fish feed to reduce production costs, without negative impact on the final product.</p&gt