The part of the diagnosis laboratory in the mastership of aquaculture of marine animals

Les particularités et la diversité des maladies affectant les pœcilu- thermes marins impliquent la compétence de pathologistes spécialisés dis posant des moyens techniques d’un laboratoire de diagnostic. L’anamnèse, les symptômes et les lésions peuvent parfois permettre de suspecter le rôle de certains bio-agresseurs ou de facteurs liés à l’environnement ou à l’alimentation. Les étiologies bactériennes et parasitaires, parce qu’elles per mettent souvent la mise en œuvre immédiate de thérapeutiques efficaces, seront cependant systématiquement recherchées.The particularities and the diversity of the diseases affecting the marine pcecilotherms involve the ability of specialized pathologists disposing of the technical means of a diagnosis laboratory. Anamnesis, symptoms and lesions can sometimes allow to suspect of the part of some bioagressors or environmental and dietary factors. Bacterial and parasitic aetiologies, because they often allow the immediate use of effective therapeutics, will be however systematically looked for

Crustacés et Helminthes parasites de l'Albacore (Thunnus albacares) du Golfe de Guinée - note préliminaire

This note presents the results of a current study on the parasitism of the yellowfin Thunnus albacares in the Gulf of Guinea: a list of encountered crustaceans and helminths, remarks concerned with localisations, frequencies and intensities of the infestations is given. A hypothesis on the existence of three ecological stocks corresponding to three great fishing areas of the Gulf is suggested

Les helminthes parasites des thons tropicaux

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Visceral myxobacteriosis in the rainbow trout, Salmo­Gairdneri R. : a new clinicat form of the Cytophaga psychrophila cold water disease

Une forme nouvelle de la myxobactériose d’eau froide est apparue en France au cours de ces dernières années chez les alevins et les trui- telles arc-en-ciel. L’agent responsable est Cytophaga psychrophila, qui ne sévissait jusqu’ici qu’en Amérique du Nord chez les salmonidés juvéniles, provoquant surtout des lésions ulcératives cutanées. En France, au contraire, les lésions causées par la bactérie sont essentiellement viscé rales. L’infection clinique est observée en saison froide, et assez souvent associée à d’autres pathologies. Le diagnostic repose essentiellement sur la mise en évidence et la caractérisation de la bactérie responsable. La maladie a été transmise expérimentalement et les essais en laboratoire ont montré l’efficacité thérapeutique du chloramphénicol et de l’oxytétra- cycline.A new form of the cold water myxobacteriosis in rainbow trout fry and Engerlings appeared in France during the last years. So far, the aetiological agent has been Cytophaga psychrophila, a myxobacteria occuring on juveniles of salmonids of North America and mostly inducing cutaneous ulcerative lesions. On the opposite, lesions observed in France have essentially been detected on internal organs. The clinical infection is prevalent during the cold season and is often associated with other pathogens. Diagnosis is mainly made on isolation and characterization of aetiological bacteria. The disease was experimentally transmitted. Trials in laboratory have also demonstrated the therapeutic efficiency of chloram phenicol and Oxytetracycline

Does dietary tocopherol level affect fatty acid metabolism in fish?

Fish are a rich source of the n-3 polyunsaturated fatty acids (PUFA), particularly the highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic (DHA; 22:6n-3) acids, which are vital constituents for cell membrane structure and function, but which are also highly susceptible to attack by oxygen and other organic radicals. Resultant damage to PUFA in membrane phospholipids can have serious consequences for cell membrane structure and function, with potential pathological effects on cells and tissues. Physiological antioxidant protection involves both endogenous components, such as free radical scavenging enzymes, and exogenous dietary micronutrients including tocopherols and tocotrienols, the vitamin E-type compounds, widely regarded as the primary lipid soluble antioxidants. The antioxidant activities of tocopherols are imparted by their ability to donate their phenolic hydrogen atoms to lipid (fatty acid) free radicals resulting in the stabilisation of the latter and the termination of the lipid peroxidation chain reaction. However, tocopherols can also prevent PUFA peroxidation by acting as quenchers of singlet oxygen. Recent studies on marine fish have shown correlations between dietary and tissue PUFA/tocopherol ratios and incidence of lipid peroxidation as indicated by the levels of TBARS and isoprostanes. These studies also showed that feeding diets containing oxidised oil significantly affected the activities of liver antioxidant defence enzymes and that dietary tocopherol partially attenuated these effects. However, there is evidence that dietary tocopherols can affect fatty acid metabolism in other ways. An increase in membrane PUFA was observed in rats deficient in vitamin E. This was suggested to be due to over production of PUFA arising from increased activity of the desaturation/elongation mechanisms responsible for the synthesis of PUFA. Consistent with this, increased desaturation of 18:3n-3 and 20:5n-3 in hepatocytes from salmon fed diets deficient in tocopherol and/or astaxanthin has been observed. Although the mechanism is unclear, tocopherols may influence biosynthesis of n-3PUFA through alteration of cellular oxidation potential or “peroxide tone”

Oncophora melanocephala (Rud, 1819) n. comb., N\ue9matode Camallanidae, parasite du Thon Albacore Neothunnus albacares

Volume: 42Start Page: 984End Page: 98

Oncophora albacarensis n. sp. (N\ue9matode, Camallanidae) parasite du thon Albacore Thunnus albacares

Volume: 96Start Page: 1329End Page: 133

Phyllodistomum thunni n. sp. (Trematoda, Gorgoderidae). Tr\ue9matode parasite du Thon albacore Thunnus albacares

Volume: 166Start Page: 1041End Page: 104

Deux esp\ue8ces du genre Philometra (Nematoda, Dracunculoidea) parasites de Thons

Volume: 8Start Page: 769End Page: 77