23 research outputs found
Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Cameroon
This report is an output of the project âDetermination of high-potential aquaculture development areas and impact in Africa and Asiaâ. This monograph is the case study for Cameroon. Written in three parts, it describes the historical background, practices, stakeholder profiles, production levels, economic and institutional environment, policy issues, and prospects for aquaculture in the country. First, it documents the history and current status of the aquaculture in the country. Second, it assesses the technologies and approaches that either succeeded or failed to foster aquaculture development and discusses why. Third, it identifies the key reasons for aquaculture adoption
Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Cameroon
This report is an output of the project ÎDetermination of high-potential aquaculture development areas and impact in Africa and Asiaö. This monograph is the case study for Cameroon. Written in three parts, it describes the historical background, practices, stakeholder profiles, production levels, economic and institutional environment, policy issues, and prospects for aquaculture in the country. First, it documents the history and current status of the aquaculture in the country. Second, it assesses the technologies and approaches that either succeeded or failed to foster aquaculture development and discusses why. Third, it identifies the key reasons for aquaculture adoption.Freshwater aquaculture, Policies, Economic analysis, Marketing, Trade, Research, Fishery industry, Cameroon,
Effets comparĂ©s des doses de lâhormone 17-alpha-methyltestosterone et du milieu dâĂ©levage sur les taux de masculinisation, de survie et de croissance des larves du tilapia Oreochromis niloticus en zone dâaltitude camerounaise
Lâun des principaux obstacles au dĂ©veloppement de lâaquaculture au Cameroun est le manque dâapprovisionnement en alevins et juvĂ©niles en quantitĂ© suffisante lorsque le besoin se pose. Lâobjectif est de dĂ©terminer quelles sont les voies dâamĂ©lioration de la pisciculture en Ă©tang et en Ă©closerie dans le cadre du dĂ©veloppement durable des productions halieutiques au Cameroun. A cet effet, une Ă©tude a Ă©tĂ© rĂ©alisĂ©e Ă BatiĂ© dans la rĂ©gion de lâOuest du Cameroun afin de rechercher la dose optimale de lâhormone 17-alpha-methyltestosterone (17--MT) et lâeffet du milieu sur les taux de masculinisation et les performances zootechniques des alevins du tilapia Oreochromis niloticus. Ainsi, 3 mĂąles et 9 femelles matures de poids moyens individuels respectifs de 250 g et de 200 g sortant dâune phase de repos sexuel ont Ă©tĂ© mis en reproduction dans un bac bĂ©tonnĂ© en Ă©closerie. Deux semaines aprĂšs, une pĂȘche de contrĂŽle a rĂ©vĂ©lĂ© la prĂ©sence de larves dans la cavitĂ© buccale des femelles. Ces larves ont Ă©tĂ© extraites et rĂ©parties dans 9 bassins de 50 litres chacun installĂ©s en Ă©closerie Ă eau contrĂŽlĂ©e et dans 9 happas de 1,8 mÂł installĂ©s dans des Ă©tangs Ă eau non contrĂŽlĂ©e. Les bassins contenaient chacun 220 larves et recevaient en triplicata trois aliments expĂ©rimentaux contenant chacun respectivement 50, 55 et 60 mg de lâhormone 17--MT/kg dâaliment. La mĂȘme procĂ©dure a Ă©tĂ© faite en Ă©tang. AprĂšs 31 jours dâĂ©levage, la ration Ă base de 55 mg de 17--MT/kg dâaliment a prĂ©sentĂ© significativement (p < 0,05) les meilleurs rĂ©sultats et lâĂ©closerie le meilleur milieu dâĂ©levage. Les interactions doses dâhormone et milieu dâĂ©levage ont montrĂ© que lâhormone a contribuĂ© respectivement Ă 60,75 ; 76,25 et 54,23% de masculinisation, le gain moyen quotidien et le taux de croissance spĂ©cifique. Le milieu dâĂ©levage a participĂ© respectivement Ă 92,29 ; 56,16 et 77,25% sur la survie, le quotient nutritif et le facteur de condition. Ces rĂ©sultats suggĂšrent de prĂ©coniser lâaliment Ă 55 mg de 17--MT et lâĂ©closerie pour une meilleure production du tilapia Ă 100% mĂąles ayant une bonne potentialitĂ© de production.Mots clĂ©s : Alevins, Ă©closerie, Ă©tang, tilapia, hormone
DĂ©termination des caractĂ©ristiques de maturitĂ© sexuelle du Cyprinus carpio en zone dâaltitude Camerounaise
LâĂąge, la taille et le poids de maturitĂ© sexuelle ont Ă©tĂ© Ă©tudiĂ©s sur 200 Cyprinus carpio Ă partir de 3 mois dâĂąge en grossissement dans un Ă©tang Ă BatiĂ© (climat Soudano-guinĂ©en, Ouest-Cameroun). Lâabattage et la dissection de 20 spĂ©cimens choisis au hasard tous les deux mois ont Ă©tĂ© rĂ©alisĂ©s sur une pĂ©riode de 19 mois. Au terme de ce travail, il est apparu que lâĂąge de reconnaissance du sexe des gonades du Cyprinus carpio est de 5 mois. LâĂąge de maturitĂ© sexuelle des mĂąles est de 11 mois au poids de 189,65±4,0 g Ă la longueur totale de 24,35±1,8 cm tandis quâil est de 13 mois pour les femelles au poids de 187,16 ± 30,4g Ă la longueur totale de 25,1±1,8 cm.Mots clĂ©s: Age, taille, poids, maturitĂ© sexuelle
Effet de la couleur, du diamĂštre et du stade ovocytaire sur les performances de la reproduction induite deCyprinus carpio en zone soudano-guinĂ©enne dâaltitude
Une Ă©tude sur lâeffet de la couleur, du diamĂštre et du stade ovocytaire sur la fĂ©conditĂ© relative, les taux de fĂ©condation et dâĂ©closion des femelles de Cyprinus carpio en reproduction induite a Ă©tĂ© rĂ©alisĂ©e en zone soudano-guinĂ©enne des hautes terres de lâOuest-Cameroun. Pour la couleur, le diamĂštre et le stade ovocytaire, deux modalitĂ©s ont Ă©tĂ© respectivement utilisĂ©s : ovocyte blanc, ovocyte jaune ; ovocyte jaune de diamĂštre supĂ©rieur Ă 1,2 mm, ovocyte jaune de diamĂštre infĂ©rieur Ă 1,2 mm ; ovocytes jaunes au stade II et ovocytes jaunes au stade III. Pour chaque modalitĂ©, quatre reproductions induites ont Ă©tĂ© rĂ©alisĂ©e. A cet effet, 72 jeunes gĂ©niteurs jamais reproduits dont 48 mĂąles et 24 femelles ont Ă©tĂ© utilisĂ©s. Les reproductions induites ont Ă©tĂ© rĂ©alisĂ©es dans deux Ă©tangs en dĂ©rivation clĂŽturĂ©s en bambou de superficie respective 150 et 170 mÂČ. La ponte a Ă©tĂ© induite en injectant les femelles Ă lâovaprim et les mĂąles au HCG. Au terme de ce travail, il est apparu que le diamĂštre et la couleur ovocytaire influencent la fĂ©conditĂ© relative, les taux de fĂ©condation et dâĂ©closion en reproduction induite. La fĂ©conditĂ© relative des femelles aux ovocytes jaunes a Ă©tĂ© significativement supĂ©rieurs (p<0,05) Ă celle des femelles aux ovocytes blancs (93995,29±165,51 contre 18206,19±162,72) et les taux de fĂ©condation et dâĂ©closion des ovocytes jaunes ont Ă©tĂ© significativement plus Ă©levĂ©s que ceux des ovocytes blancs (61,50±11,70% contre 0,00% et 52,00% contre 0,00%). Les femelles aux ovocytes jaunes de diamĂštre supĂ©rieur Ă 1,2 mm ont une fĂ©conditĂ© relative significativement supĂ©rieur (p<0,05) Ă celle des femelles aux ovocytes jaunes de diamĂštre infĂ©rieur Ă 1,2 mm (114306,20±1022,69 contre 45269±9948,28) et les taux de fĂ©condation et dâĂ©closion ont Ă©tĂ© comparables. Aucune diffĂ©rence significative nâa Ă©tĂ© dĂ©celĂ©e pour la fĂ©conditĂ© relative, les taux de fĂ©condation et dâĂ©closion des ovocytes au stade II et III.Mots clĂ©s : Cyprinus carpio, ovocyte, reproduction induite, fĂ©conditĂ©, taux de fĂ©condation et dâĂ©closion
L'alimentation du tilapia Oreochromis niloticus en etang
*INRA, Station d'Hydrobiologie, Nutrition des Poissons,Saint Pee sur Nivelle (FRA) Diffusion du document : INRA, Station d'Hydrobiologie, Nutrition des Poissons,Saint Pee sur Nivelle (FRA) DiplĂŽme : Dr. Ing
Evaluation of the suitability of various dry and moist feeds for rearing larvae of the catfish, Heterobranchus longifilis (Teleostei, Clariidae)
The effects of various dry and moist diets on water quality, feeding behaviour, mortality and growth of the African catfish (Heterobranchus longifilis) larvae were investigated in a twelve day feeding trial. Five food types and one reference diet were tested in duplicate: Beef liver (BL), beef brain (BB), beef liver and beef brain (BL & BB), toasted soya beanmeal (SB), SB and tilapia fish meal (FM). The reference diet consisted of decapsulated Artemia cysts (AC). One group of larvae received no food (NF) and was included to determine their survival under starvation. The larvae were fed in excess of their requirements, 6 times during the daytime at 2-hour intervals, from the onset of exogenous feeding,which occurred 56-62 hours after hatching.Water quality did not undergo any degradations likely to induce fish kills. The final mean length (16.7 mm) and weight (38.5 mg), growth rate (3.06 mg.d-1), specific growth rate (31.4 %.d-1), condition factor (0.83) and survival rate (91.4 %) of fish fed decapsulated Artemia cysts were significantly higher than those of fish fed other diets (P less than 0.05). The dry diets based on soya and fish meal led to significantly lower growth and survival rates in comparison to the moist diets based on beef liver and beef brain.The results also indicated that the moist diet based on the mixture of beef liver and beef brain produced the highest specific growth rate (19.04 %.d-1) and survival (68 %) compared to other dry and moist diets. It was observed that larvae in starving conditions increased in length up to 5 days of age, and 7% survived at the end of the trial
Effect of Feeding Frequency on the Growth of Tilapia (Oreochromis niloticus) in Earthen Ponds
Duplicate groups of Nile tilapia fingerlings (30.9 g) were fed at three different frequencies, i. e. 2, 3 and 6 meals a day, in six 400 m2 earthen ponds. Fish stocked at 22.4 g/m2 (about 60 ind./are) was thus fed an experimental diet containing 25 % protein from vegetal origin. The feed was daily distributed, by hand, at equal time intervals between 8 a. m. and 3 p. m. After fifteen weeks trials, significantly (p <0.05) best growth was obtained in the 6 times a day treatment (daily growth rate 1.3 g/day as compared to 0.9 g/day for each of the two other treatments). It could be noticed that increase in the feeding frequency was associated with increase in growth rate and decrease in FGR (from 1.6 to 1.3). In term of fish production, there was an estimated extra tilapia production of 8.7 kg/are/year with the 6 times a day frequency, comparatively to the two other treatments. In an environment where labour is not actually limiting, the study suggests that Nile tilapia in production ponds should be fed six times a day
Nitrogen and energy utilization by Oreochromis mossambicus fingerlings fed diets containing graded levels of brewery draff
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Evaluation of practical diets with three levels of protein and lipids for juvenile Hemichromis fasciatus Peters (Teleostei, Cichlidae)
Three experimental diets, containing 29, 37 and 44% protein levels, with respectively 20.0, 20.6 and 21 kJ/g crude energy contents were prepared and their effect on growth and feed utilisation were evaluated for juveniles (1.2 g) of Hemichromis fasciatus, a cichlid commonly used as âpoliceâ fish in tilapia ponds of sub-saharian countries. The significantly highest growth (SGR=1.90) and protein retention efficiency (PRE=35.3%) were obtained in outdoor rearing structures with the 29% protein diet. However, no significant difference was found for feed conversion ratio and energy retention efficiency. Most of the parameters tended to decrease with increasing dietary protein and lipid level. As a consequence, although adults of Hemichromis seem to depend essentially on tilapia fry for their feeding, the present study suggests that adietary protein close to 29% with a P / E ratio of about 15 mg protein per kJ energy is better for H. fasciatus juveniles than higher levels. This trend meets what is observed with some other cichlids as the Nile tilapia. A design using lower ranges of dietary protein and lipid needs to be investigated.Key words: Hemichromis, protein diets, fish feeding, Cameroo