Amino acid and protein supplementation of chick diets containing single cell protein sources¹

Rowett Research Institute Reprint No. 638.

Synopsis

Six samples of yeasts grown commercially on hydrocarbon oil, two bacterial protein preparations and a distillery yeast were compared in chick growth experiments of the total protein efficiency type. Various combinations of amino acids were incorporated and evaluations were also made of mixtures of the single‐cell protein sources with conventional protein foods.

When combined with cereals only, the nutritive value of the single‐cell protein sources was not influenced by amino acid supplementation to the extent expected but in the presence of a proportion of a conventional protein supplement such as fish, groundnut, soyabean or sunflower seed meal satisfactory responses were obtained. With methionine addition yeast could replace to advantage half of the total fish meal in a fish meal‐cereal diet, and two‐thirds replacement gave growth equivalent to that obtained with the all‐fish meal diet. Considerable improvements were achieved also by partially replacing each of the other types of concentrate by single‐cell protein sources.

No explanation is available at present for the failure of amino acid supplementation to improve the yeast‐cereal diets. Increasing the level of vitamins did not produce a significant effect.

Notes

Rowett Research Institute Reprint No. 638.