One of the most important problems in aquaculture sector is the reduction in feed costs and production of high-quality feed. The fact that fish meal production is limited and its price is high leads the fish feed producers to use alternative raw materials.

Dr. Gökalp AYDIN
Assocation of Feed Additives Producers, Importers and Distributors
Secretary General 

In years, fish farming in Turkey has become a booming sector as there has been limited fish stock that decreased even more as a result of overhunting and pollution even though Turkey is surrounded on three sides by seas. Increasing population and the increase in per capita income, as well as the fact that fish is a good source of protein from the health point of view, all contributed to the growth of fish farming. The figure speaks for itself. In the last seven years, fish farming in Turkey has grown by 65 percent. In 2017, aquaculture production in the country was 276,502 tons. In the world, annual aquaculture production in sea and inland waters was 80,071,894 tons in 2016.
In the production of aquaculture, there are many factors such as water cleaning, its temperature, pH, cage or pool management that affects the productivity. Among these, the feed affects most the productivity and the cost. Approximately speaking, the feed constitutes seventy percent of the cost of production. So, one of the most important problems for the aquaculture producers is to procure quality and low-cost feed. The main component of the fish feed is the fish meal. However, increasing exchange rate, instability in the production of fishmeal around the world, and the price hike led in the rise the cost of fishmeal. Thus, the fish feed producers have been looking into alternative raw materials that can replace the fishmeal.

The production of aquaculture in Turkey and in the world
Turkey is surrounded on three sides by the sea. Nevertheless, overhunting and pollution decreased the natural fish stock- that’s why only hunting cannot meet the demand for fish and other aqua plants- an important source of protein-taking into consideration of increasing population. This picture is true for the world as well. So, the fish farming has become a booming sector at inland waters and seas in the world and in Turkey. Table 1&2 provides the figure on the aquaculture production in the world and in Turkey.

Table 2 shows that the amount of fisheries by hunting has decreased in the country while the amount of aquaculture has increased. This fact has increased the importance of feed in aquaculture production. Additionally, year-by-year, the increase in the aquaculture production has been in parallel to the increase of aquaculture export. The amount of import and export is provided in Table 3.

In recent years, there has been a significant increase in exports of fisheries. Despite the increase in aquaculture and exports, the annual per capita consumption of fisheries in Turkey is well below the world average. While the average annual aquaculture consumption per capita in the world is 16 kg. and 23 kg. in Europe, the amount for Turkey, which is surrounded by seas on three sides, was avarage 5.5 kg in 2017 (Aydın et al., 2010) (TUIK, 2017).
Moreover, all of the fisheries produced are not for human consumption. Approximately 100,000 tons of aquaculture is processed in fish meal facilities and converted into fish meal and fish oil- the main raw materials of fish feed. Table 4 provides information on the amount of most-produced type of fisheries in Turkey.

Feed Problem
Just like in all other livestock activities, the most important input in aquaculture is the feed. Feed production technology and feeding methods are of course important in the production of aquaculture; however, we will focus more on the input costs in the feed. Approximately speaking, the feed constitutes seventy percent of the cost of production. So, one of the most important problems for the aquaculture producers is to procure quality and low-cost feed. The total amount of produced mixed feed for all animal species in Turkey as of 2017 is 22.5 million tons. Of this amount, 512.726 tons are for fish feed (Table 5).

Generally speaking, the content of the fish feed is fishmeal, fish oil, soybean, and its byproducts, hydrolyzed fish protein, wheat, and its byproducts, corn gluten, yeast, and its byproducts, lecithin, amino acids, vitamins, and minerals. Rationally, the most used raw material is fishmeal and fish oil, and the price of these products is high; so, the cost of fish feed is high which also increases the fish feed.
Forty-fifty percent of the fish feed is fishmeal although its percentage varies according to the type and growth period of fish; however, this percentage decreased to twenty-thirty percent because of the increase in the price of fishmeal. The digest of feed is directly related to the growth and development of fish. The growth of fish fed by two separate rations of the same energy and protein level but different raw materials may be different. The fishmeal is one of the best raw materials considering its protein quality, digestibility, and amino acid balance.
One of the problems that producers usually voice is the increase in the feed conversion ratio (FCR). In this ratio; many factors such as the type of fish and water temperature have influence. Yet, the main problem is the quality of the feed; in other words, the content of raw material and its digestibility in the feed are considered as the main problem. In previous years, the fish is put on the market within eight-to-ten months. Today, this duration is extended to twelve months. The main reason behind this fact is considered as the reduction or even non-existence of fishmeal in the ratio. The producers also said that the non-existence of rehabilitation works has an influence on this reality (Central Union of Fisheries Producers Notes 2018).
Turkey’s fishmeal and fish oil import were is 123 thousand tons and 40 thousand tons in 2017 respectively. The amount paid for fishmeal import was 155 million dollars (TUIK, 2017). The fact that fishmeal and oil are expensive raw materials caused fish feeders to search for alternative raw materials.

Alternative Raw Materials
Soybean and soybean products:
As an alternative to fishmeal, soybean and its products are mostly used because of their rich protein content. However, in practice, soybean meal cannot replace for the fish meal.
Single cell protein:
The single cell protein obtained from yeast or bacteria. It has been reported that single cell protein substitution in the level of five-to-ten percent instead of soy in the ratio does not make a statistical difference on growth performance and feed treatment in trout (Hardy et al. 2018). In another survey, it was stated that single cell proteins obtained from bacteria could be substituted up to 27 percent instead of fish flour in rainbow trout, and no difference in growth performance was observed (Truid et al. 2006).

In order to have the desired development in fish, it should be fed with Omega-3-rich fish oils. Since the fish oils are as expensive as fishmeal, alternatively, algae meals rich in Omega-3 fatty acids are used. Algae meals are rich in terms of Omega-3 fatty acids. It has been reported that the addition of a small number of algae (< ten percent) to fish feeds has a positive effect on development and feed treatment (Norambuena et al. 2015). Although the protein value of algae is generally high, this ratio varies according to its species. In its growth phase, microalgae usually contain thirty-to-forty percent protein, ten-to-twenty percent lipid, and five-to-fifteen percent carbohydrate in dry matter (Özçiçek et al. 2017). There may be algae with low values. So, there is a need for selection of suitable species for fish feed and further research in this area.

Animal by-products (meat- bone flour, chicken meal, feather meal):
Because of the in-breeding prohibition of the Ministry of Agriculture and Forestry in 2017, the prices of chicken meal decreased. Chicken flour is mostly used in the feeds of domestic animals such as cats and dogs, but it is also used in fish feeds at five-to-ten percent.

Insect protein:
Insects are a protein-rich source that can be used as both animal feed and human food. Insects with a rich nutrient content can be considered as a low-cost protein source in poultry and fish feeds. The protein value of insect meals varies between forty to sixty percent on average and has a rich content of essential amino acids than soybean meal. The methionine value is lower compared to fish meal. Insects are very good energy sources because of their oil content. Nowadays, protein sources such as soybean meal and fish meal are expensive, and animal protein sources such as fish meal are limited. That’s why; insect protein is seen as an alternative protein source, which can substitute their place. The amino acid compositions of some insects and fish meal are given in Table 6.

With the European Union’s 24 May 2017 dated and 2017/893 numbered regulation, the processed proteins obtained from insects were allowed to be used as feed in aquaculture under certain conditions. While insect protein is used in aquaculture in developed countries such as Europe, America and Canada, insect proteins are still not allowed to be used in aquaculture in Turkey (Aydın G., 2017).

Aquaculture has become a growing sector in Turkey as well as in the world. The most important problems in this sector are the feed costs and difficulty in supplying high-quality feed. The fact that fish meal production is limited and its price is high leads the fish feed producers to use alternative raw materials. Different products are used in this regard, but in order to achieve optimum yield and sustainability in aquaculture, more research and development studies in the feed are required.

– AAS S. TRUID, HATLEN B., HELLAND B., TERJESEN B., MCKELLEP A., HELLAND S. (2006). Effects of diets containing a bacterial protein meal on growth and feed utilisation in rainbow trout. https://www.sciencedirect.com/science/article/abs/pii/S0044848606005278

– AYDIN G. (2017). Böcek Proteini. Yem Sanayicileri Birliği, Yem Magazin Dergisi. Haziran 2017, sayı 79

– AYDIN H., DILEK K.M., AYDIN K. (2011). Trends in Fish and Fishery Products Consumption in Turkey. Turkish Journal of Fisheries and Aquatic Sciences 11:499-506 (2011)

-HARDY W.R ., PATRO B., BAXLEY C., MARX C., FEINBERG L. (2018) Partial replacement of soybean meal with Methylobacterium extorquens single-cell protein in feeds for rainbow trout.

– JOSEFIAK D, ENGBERG MR (2015). Insects as Poultry Feed. 20th European Simposium on Poultry Nutrition. 24-27 August 2015. Prague, Czech Republic

-NURAMBUENA F., HERMON K., SKRZYPCZYK V., EMERY J., SHARON Y., BEARD A., TURCHINI G. (2015). Algae in Fish Feed: Performances and Fatty Acid Metabolism in Juvenile Atlantic Salmon. https://www.researchgate.net/publication/275215135

– ÖZÇİÇEK E., CAN E., YILMAZ K., CAN Ş., (2017). Akuakültürde Sürdürülebilir Besin Kaynağı Olarak Mikroalglerin Kullanımı. Ege Journal of Fisheries and Aquatic Sciences, 34(3): 347-354 (2017)

– Su Ürünleri Yetiştiricileri Merkez Birliği Notları 2018. Ankara

– TUİK, 2017. www.tuik.gov.tr

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