July 1, 2008

Study finds half of fishmeal in cod feed can be replaced by soymeal

A Norwegian study has found that up to half the fishmeal content in cod feed can be replaced by plant protein without any negative impact.

The study was conducted by Ann-Cecilie Hansen from the National Institute of Nutrition and Seafood Research (NIFES). Hansen is a PhD student at the University of Bergen.

In one of her studies, cod weighing 140 grammes were fed feed with mixtures of soy meal, soyprotein concentrate, corn gluten and wheat gluten. The inclusion levels of the raw materials differed.

Raw materials like soymeal, wheat gluten and soy protein concentrate appeared to have the most positive effect on the cod's growth and health, said Hansen.

In a new trial, different protein mixtures of these raw materials was made. Fishmeal was replaced by plant proteins from 0 to 100 percent. The feed was given to cod of about 1.6 kilogrammes.

It was shown that replacement levels up to 50 percent had no negative effect on the growth or the health of the cod. Growth and feed utilisation was reduced by replacing over 50 percent of fish meal with plant meal.

However, replacement levels just over 50 percent is unlikely to affect the cod negatively provided that amino acids, vitamins and minerals common in fishmeal but in short supply in plant protein is added to the feed, the study said.

At the 100 percent replacement level, intestinal changes which resembles inflammatory conditions was observed in cod.

Hansen was awarded for her presentation of her two feeding trials at the "International Symposium on Fish Nutrition and Feeding" (ISFNF), held in Brazil, Florianopolis, June 2-5, 2008.