Yeast is a high-quality feed ingredient with a protein content of 50 to 55 per cent and a favourable amino acid composition. But yeast as a protein ingredient cannot compete with the low cost of plant proteins, such as soy.
Foods of Norway researchers have performed several experiments with yeast in diets for Atlantic salmon. The results show that fish fed yeast have a high feed intake and growth rate, as well as high feed efficiency. The nutritional value still needs to be optimized, which is an important research area in the centre.
Through these experiments with salmon, researchers have found that certain strains of yeast have positive health effects such as reducing inflammation in the gut, increasing protection against pathogens and stimulating a series of immune responses in the fish. Yeast also has beneficial health effects for fish in sensitive periods, such as during their transfer to seawater. Findings such as these are highly relevant for the salmon industry, which experiences high losses during this period.
Yeast has also been tested as a protein source in diets for piglets during the stressful time of weaning. The piglets ate and grew well, and the yeast-based feed reduced post-weaning diarrhoea, amongst several other positive effects.