Disease Control In Aquaculture Research Articles

Anti-infectious immune effectors in marine invertebrates: potential tools for disease control in larviculture

The aquaculture of molluscs and crustaceans is an economical activity that is threatened by the repeated appearance of new diseases, non-infectious and infectious, which affect cultured species. Difficulties in controlling diseases in marine aquaculture come mainly from the differences in susceptibility of the animals according to their developmental stage (from larvae to adults) and from the diversity of pathogens that affect them. Among the causative agents encountered in marine aquaculture, viral and bacterial problems as well as fungal diseases dominate the larval production. Methods have been proposed for the control of disease in aquaculture, such as the use of probiotic bacteria, immunostimulants or the improvement of the larval quality via the nutrition, and zootechnical progress has been made. So far, antibiotics have been intensively used as preventive and curative measures, but such practices are now questioned because regular use of these chemical products has led to the appearance of drug-resistant bacteria and can also have harmful effects on the environment. In this context, alternative treatments as well as animal health monitoring have to be established as preventive measures. In the long term, the most effective way for sustainable aquaculture production will certainly rely upon the production of animals selected for increased resistance to disease, but until now, few papers can be found on this topic for marine invertebrates. Today, immune criteria as enhancement of non-specific defence responses are being considered. Investigation of the innate immune systems of molluscs and crustaceans may give new insights into the management and control of diseases in aquaculture. In particular, antimicrobial peptides present various application possibilities by their use as therapeutic agents, as tools for monitoring the health status of cultured animals, and by the use of encoding genes as selection markers for improving resistance to infections.

Applications and needs of fish and shellfish cell culture for disease control in aquaculture

This review focuses on the application of cellculture and in vitro methods to addresssome of the key elements identified asstrategies for integrated health management inaquaculture, including the standardization andvalidation of diagnostic methods, thedevelopment of new safe therapeutants, and theimplementation of effective disease controlmethodologies. It is expected that anylong-term rise in seafood production willdepend on the future progress of aquaculture.However, the development of aquaculture faces anumber of problems, of which diseases –particularly the emergence of new pathogens –represent serious risks for the production ofaquatic animals, but also for the health offish farmers and of the consumers ofaquaculture products. The complex interactionsunderlying disease outbreak and progression maybe better studied using in vitro modelsthat use cell/tissue culture methods andexperimental systems, in which the interactionsbetween aggressors and the host can bedissected. Researchers have developed invitro assays for fish toxicological,pathological, and immunological studies, as thein vitro assays allow higher control ofthe conditions of the experiments. Thecombination of cell/tissue cultures and invitro assays reduces also the variability ofthe in vivo responses, which are due tothe unavoidable effects of stress and ofenvironmental influences, and to the disparategenetic backgrounds of farmed fish andshellfish species.

Review of disease control in aquaculture in the Republic of South Africa

The disease control measures in respect of domestic and wildlife aquatic species in the Republic of South Africa (RSA) are shared between two Directorates in the Department of Agriculture. The Directorate of Animal Health is responsible for disease control measures in respect of Salmonidae, while the Directorate of Plant and Quality Control regulates the introduction of exotic and unwanted aquatic species into the RSA. The activities and interests of commercial aquaculture are coordinated through the South African Aquaculture Organization and a national coordinating committee under the control of the national Department of Agriculture. Four diseases of trout are notifiable under the terms of the Animal Diseases Act (Act 35 of 1984), namely viral haemorrhagic septicaemia, infectious pancreatic necrosis, infectious haematopoietic necrosis and bacterial kidney disease. The zoosanitary measures in respect of these diseases require State intervention after detection of occurrence. Sampling procedures for the diagnosis of diseases, maintenance of the disease-free status of trout farms accredited for export purposes and requirements for the import of ova are based on the standards recommended in the International Aquatic Animal Health Code of the Office International des Epizooties. Zoosanitary control of other aquatic species not related to aquaculture--especially ornamental fish--may be unnecessary. An embargo, through existing legislation on the importation of unwanted species, has been the only means of protecting inland species. The author concludes by evaluating the need for, and the feasibility of, additional legislation for the zoosanitary control of other aquatic species.