Fish Farming

[Raven]

Aquaculture Research Information Sheet: Nutrition Research
One of the main factors limiting the expansion of aquaculture is the development of nutritionally adequate, cost-effective diets. Feed and feeding can contribute up to 70% of total operating costs for fish and prawn farms. The protein source of choice for most aquaculture diets is fishmeal yet this ingredient is only produced in very small quantities in Australia. Global production of fishmeal is static or declining yet demand, especially for aquaculture, is increasing rapidly. This has led to price escalation.

Replacement of fishmeal is a major international research priority. In Australia we have abundant supplies of agricultural proteins, including vegetable and animal meals, and we have been very successful at utilising these ingredients to produce very cheap, cost-effective diets for pigs and poultry. At NSW Fisheries we have now developed high-performance diets without fishmeal for the freshwater native silver perch. Research with snapper is also underway and low fishmeal diets have been successful at a laboratory scale. Collaborative research with other species, eg. barramundi, prawns and salmon has also been successful.

Research is continuing to evaluate and improve alternative ingredients to fishmeal. Some of the most promising ingredients include high protein, low-ash meatmeals, poultry-offal meal, de-hulled lupins and modified wheat gluten products. Oilseeds and other grains are also valuable ingredients. Further processing of some ingredients such as fine grinding and the removal of husks or cooking can increase the use of Australian agricultural ingredients. Defining nutritional requirements is also an important priority. Research in this area on protein requirements at different energy contents has been successfully completed for silver perch and snapper. Work on defining requirements for essential fatty acids has also been completed for silver perch. Requirements must be met for rapid growth and oversupplying essential nutrients is expensive and can increase problems with water quality.