Antimicrobial agents in aquaculture: Practice, needs and issues

Abstract

Aquaculture is a fast-growing food production sector and the need for antimicrobial agents varies markedly between countries. Intensification of aquaculture has led to the promotion of conditions that favour the use of a wide range of chemicals, including antibiotics, pesticides, hormones, anaesthetics and various pigments. The quantities used and the usage patterns also vary between countries and individual aquaculture operations. However, the market for aquaculture antimicrobials is small and the approval process for new compounds is expensive. Antibiotics can be used in fish to effectively treat bacterial diseases but are not for growth promotion as in other food-producing industries. Antifoulants that contain biocides and pesticides used for treatment of certain parasites are also used in aquaculture operations. The provision of increased selection pressure leading to antibiotic resistance can occur by overuse or misuse in human medicine, livestock, agriculture, horticulture and aquaculture. There are virtually no antimicrobial agents available for treatment of molluscan or crus tacean diseases and alternative control measures are therefore required. Alternatives to the use of antimicrobial agents include good husbandry, adequate feed composition, vaccines, biological control and movement restrictions through legislation. Further research is required in areas such as vaccine development, immunostimulants and the use of probiotics.