Application of soy protein concentrate instead of fish meal in aquaculture

Martec is a farm located in Costa Rica with advanced equipment and good water environment. Martec Industries is one of the largest fish processing companies in Central America and the first company to raise snappers commercially. At present, the company’s business scope includes hatching snapper eggs to sales of adult fish. Martec Industries is committed to finding the best quality resources to replace fishmeal and fish oil, and use this as an important raw material for snapper feed.

According to the data, in a recent experiment of the company, there are data confirming that the protein content of soy protein concentrate in the feed products that partially replace fish meal and fish oil can reach 55.37%, and the protein content of soybean anti-nutritional factors and trypsin inhibitors The content is lower than the industry standard.

Preliminary preparations for the experiment

The experiment lasted for 75 days and was carried out at Martec’s cage farm in Costa Rica. The farm is located in Paquera, Puntaranas province, near Isla Cedro. The main purpose of the farm is broodstock breeding and other experimental research involving the nutrition and reproduction technology of adult fish.

The experiment uses three different types of feed as test samples:

Sample 1, a feed using soy protein concentrate as a raw material, with a crude protein content of 50%, a fat content of 13%, and a total content of 26.4%;

Sample 2, the local produced feed has similar nutritional composition to sample one;

Sample 3, some kind of feed sample from Japan.

The experiment is divided into 12 units, each of which is an experiment box with a size of 1.3 cubic meters. All the experiment boxes are placed in two culture cages with sufficient water exchange. The seabream fish used in the experiment came from the hatchery of Martec Company. The larvae in the hatchery weighed 2.39g per tail, and the stocking density was 170 per box. During the process, the cage of the experiment box was cleaned every 10 to 12 days.

Finally, the sample used for statistical experiment data is 240 fish, which come from the above-mentioned 12 different experimental units, and the unit weight of each fish is determined separately during the sampling process.


Related data and results

The experiment uses four methods to feed the fish, each method is carried out randomly. Statistics show that 60% of the time is fed 4 times a day; 17% are fed three times a day; 11% are fed once or twice a day; 12% are fed no feeds a day. The environmental parameters of the water body where the cages are located are stable, with an average temperature of 27.6±0.45°C and a dissolved oxygen level of 5.38±0.94mg/L.

At the end of the experiment, the data of each group of samples are as follows:

Body weight, the average sea bream fed with sample 1 was 43.63 g, the average sea bream fed with sample 2 was 43.88 g, and the average sea bream fed with sample 3 was 45.82 g;

The survival rate is 90.2%, 98.0%, 87.6%, respectively; the biomass is 5.58kg, 6.10kg, 5.57kg per cubic meter;

The body weight growth rate was 17.2 times, 17.3 times, and 18.1 times, respectively; the feed conversion rate was 1.39, 1.32, and 1.39, respectively.


Analysis and discussion

Obviously, the measured parameters are not significantly different among the three sample groups. This result proves that when there are cost constraints, the use of soy protein concentrate can be effectively used as one of the raw materials for snapper feed, thereby partially replacing fish meal and fish oil.

Earlier in 2012, experts proposed that conventional soybean meal in snapper feed can replace up to 20% of fish meal. In this experiment, it was also proved that feed containing soy protein concentrate and traditional feed had similar effects on sea bream. Therefore, soy protein concentrate in snapper feed can be used as a substitute for fish meal, just like soybean meal, without any impact on the growth of fish.