Aquaculture has become more important to satisfy worldwide needs for fish as capture fisheries production continues to decrease. In Asia, especially in Indonesia, the aquaculture industry has been steadily increasing as a result of high demand. Aquaculture production in Indonesia had an average increase of 19.1% from 2011 to 2015, with total production of 16.6 million tonnes in 2015. The fish feed industry has also been continuously growing to support the development of aquaculture industry. It was estimated that in 2015 feed usage for main Indonesia’s cultured commodities reached 8.9 million tonnes.

As aquaculture production expands more feed is needed. Increased demand for commercial fish feed raises a number of issues related to the availability of feed raw materials, notably that some key ingredients are mainly imported. For instance, approximately 70% of fishmeal is imported, and global fishmeal supplies are increasingly scarce and expensive. This increases the price of feed and reduces the profit margin for farmers.

One of the Indonesian government's efforts to provide solutions for the feed problem is the launch of a “self-sufficient fish feed” (GERPARI) programme. The programme aims to reduce the dependence on imported raw materials, especially fishmeal, by using locally available ingredients for feed. The use of local ingredients is expected to produce good quality fish feed fish at a low price in order to improve farmer profit margin and the sustainability of the aquaculture industry. Locally available raw materials that are used are discussed below.

Soybean meal is the most common plant ingredient used in aquaculture feed because it is abundant in PUFAs (linoleic and oleic acids), but has a low n-3 PUFA content. It also has several anti-nutritional substances, but these can be removed by heating processes. Studies have reported that soybean meal can replace fishmeal from 20% to 40% in fish diets.

Palm kernel meal is one of the fishmeal substitute ingredients. It is locally abundant due to the high number of palm processing mills in Indonesia and Malaysia. Crude protein content in palm kernel meal is only around 14.90%. However, research shows that after being fermented with Aspergillus niger the protein content can reach 25.06%, while fermentation with Trichoderma koningii increases the protein content up to 32%. Studies have indicated that palm kernel meal can replace up to 20% of fishmeal in feeds.

Copra meal is a waste by-product from extraction of coconut oil. This material contains approximately 22% crude protein, has a high degree of protein digestibility and is reported not to contain anti-nutritional substances. However, it is deficient in all the essential amino acids needed by fish. A study reported that although copra meal has fairly high crude fibre content, its utilisation can reach 43% in feed of baronang (Siganus sp.).

Rice bran, wheat and maize are by-product materials from the production of rice, wheat and corn industries that can be used as a source of carbohydrates. These ingredients contain 12-15% crude protein, 60% starch and vitamins (B, E). Studies have suggested fermentation using Rhizopus oligosporus can improve the nutritional content of these materials. However, incorporation of rice, wheat and maize in the fish diets is limited to 10-20%.

Duckweed (Lemna sp and Azolla sp) have protein content on a dry weight of 23% - 45% protein with a complete composition of amino acids and high concentration of trace minerals. Therefore, it can be used directly as fish food without processing. A study has suggested that Lemna sp. can reduce the use of commercial feed up to 25% without affecting growth and survival rate in tilapia culture.

Turi (Sesbania grandiflora) is a small fast growing tropical tree. Turi leaf flour is reported to have approximately 27% crude protein. However, it contains anti-nutritional factors that significantly affect fish growth. Freshwater pomfret growth studies have suggested 10% inclusion level of fermented turi leaf flour in the diets.

Animal by-products consisting poultry meal, bone and meat meal and blood meal have a potential as an alternative replacement of fishmeal. It contains high protein content that ranges approximately from 45% to 50%. Unlike plant based proteins, these protein sources do not have anti-nutritional substances, but are low in essential amino acids required by fish. However, studies suggested that bone and meat meal can replace fish meal up to 50% in cultured Pangasius, whilst in tilapia the replacement can be up to 35%.

Shrimp head meal is obtained as a by-product of shrimp processing plants. It contains a high protein content of 53% and is normally utilised as an ingredient in shrimp feed. Studies have shown that shrimp head meal can be included into L. vannamei diets up to 18%, but only 3% in P. monodon diets. Whilst, growth experiments on Pangasius have shown that shrimp head meal can replace fishmeal by as much as 30%.

Fishmeal is derived from tuna, trevally and reef fish processing wastes or aquaculture processing wastes such as tilapia and catfish by-products. These ingredients have similar nutrient value to imported fishmeal. However, control is needed especially in terms of freshness and feasibility of using these processing wastes. Preventing microbial contamination must be carefully done. This local fishmeal has been widely used, but is always lacking in supply, especially in remote areas.

The materials described above are now used as fishmeal replacements in fish diets to varying degrees. However, intensive research on nutritional requirements and ingredients used in species-specific diets should be conducted. Feed formulations from a combination of two or more these locally available ingredients might produce better and efficient fish diets.

Another way to reduce the dependence on fishmeal is to culture low trophic level species. Herbivorous or omnivorous species have lower requirements for protein content in the diet, therefore fishmeal inclusion can be reduced in their diet formulations. For instance, farming carp and tilapia in paddy field, milkfish and shrimp in ponds.

One of the government's actions to reduce dependence on fishmeal and to equalize the distribution of fish feed is promoting home-made fish feed based on locally available raw materials. For a country that has a large area such as Indonesia, many farmers have difficulties to obtain fish feed due to their remote location. The price of fish feed in these areas is extremely expensive. Therefore, home-made feed production using locally available ingredients is one of the appropriate steps to resolve the issue. 

To sum up, three main solutions are provided to create a cost effective fish feed: 

• Reduce fishmeal level in fish diets by using locally available ingredients.
• Culture low trophic level species.
• Promote home-made fish feed based on locally available ingredients.