Drew: Use of Canola, Pea, and Soy fractions in Aquafeeds

Date: July 2009
Term: 3 years
Status: Completed
Researcher(s): Murray D. Drew, Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon
SaskCanola Investment: $39,266
Total Project Cost: n/a
Funding Partners: n/a

Project Summary

Pea meal and pea and canola protein concentrates provide a significant advantage over soybean meal in salmonid diets according to research at the University of Saskatchewan. Compared to soybean meal that shows negative effects at inclusion rates greater than 20%, pea meal and pea and canola meal concentrates do not have any negative effects on fish growth at levels up to 30% of the diet or nutrient digestibility at levels of up to 40%.

Researchers have compared various plant proteins as possible replacements for fish meal in aquaculture diets. Soybeans are the principle source of protein used for various terrestrial farm animal diets and, therefore assumed to have good potential for replacing fish meal in salmonid diets. However, a host of studies have reported that inclusion rates of greater than 20-30% soybean meal result in decreased weight gains and increased conversion rates. These effects have been attributed to the presence of anti-nutritional factors (AFNs) in soybean meal. The AFNs are lower in soybean protein concentrates and isolates, but are cost prohibitive ($1500-3000 per tonne). Therefore, researchers began looking to other plant proteins such as field pea and canola as alternatives.

The overall objective of the project was to determine the effect of inclusion rates of soybean meal (SBM), soybean protein concentrate (SPC), pea meal (PM), pea protein concentrate (PPC), canola meal (CM) and canola protein concentrate (CPC) on nutrient digestibility and growth performance of rainbow trout. Nutrient analyses were conducted on the six ingredients used in the project, including nutrient composition and anti-nutritional factors.

Digestibility Experiments

Two nutrient digestibility experiments were conducted as part of the project. The first experiment used a standard 30% inclusion rate to determine the digestibility of all ingredients to be used in diet formulations, including corn gluten meal (CGM), canola meal (CM), canola protein concentrate (CPC), pea meal (PM), pea protein concentrate (PPC), soybean meal (SBM), soy protein concentrate (SPC), fish meal and wheat. The chemical composition and Apparent Digestibility Coefficients (ADC) of the test ingredients are shown in the following tables.

The second experiment determined the effect of feeding 0, 10, 20, 30 or 40% inclusion rates of wheat, corn gluten meal (CGM), soybean meal (SBM), pea protein concentrate (PPC), canola protein concentrate (CPC) on nutrient digestibility in rainbow trout. The results showed that soybean meal has significant negative effects on energy and dry matter digestibility and should be limited in diets fed to rainbow trout. Wheat also has significant negative effects on energy and dry matter digestibility in rainbow trout and should be used at the minimum level that provides adequate pellet durability. However, canola protein concentrate and pea protein concentrate do not negatively affect dry matter, energy or protein digestibility in rainbow trout at inclusion levels up to 40%, supporting their use to replace fish meal.

Growth Performance Study

Based on the results of the digestibility experiments indicating that pea and canola might have a significant advantage over soybeans, researchers conducted a growth study. The objective of the growth study was to determine the effect of feeding pea, canola or soy products as meals or protein concentrates at graded levels up to 30% of the diet to determine the effect on growth performance of rainbow trout.

The growth performance study results show that the inclusion rates of soybean meal, soy protein concentrate and canola meal should be limited in diets fed to rainbow trout. The results also show that pea meal, pea protein concentrate and canola protein concentrate do not negatively impact the growth of rainbow trout at levels up to 30% in the diet.

The overall conclusion is that pea and canola products do have a significant advantage over soybeans in salmonid diets. Pea meal, pea protein concentrate and canola protein concentrate do not negatively impact the growth of rainbow trout at levels up to 30% in the diet, or nutrient digestibility at levels of up to 40%. Therefore, the opportunity exists to markedly increase the use of these products in aquafeed in Canada and internationally.

Table 4. Chemical composition of test ingredients (DM basis)

Table 5. Apparent digestibility coefficient (ADC) of test ingredients (DM basis)

Scientific Publications

Stephanie A. Nilson, Andrew G. Van Kessel, Janet E. Hill, Murray D. Drew, 2010. Effect of dietary inclusion rate of canola products on the growth performance of rainbow trout, Oncorhynchus mykiss. Proceedings of the International Symposium on Fish Nutrition and Feeding. June 1-4, 2010. Qingdao, China.

Full Report PDF: Use of Canola, Pea, and Soy fractions in Aquafeeds