The nutritive value of yeast protein: comparison of the supplementary values of yeast protein and casein for maize protein in the nutrition of the pig

Abstract

Since Osborne & Mendel [1919] found that rats thrived when given a diet containing brewer's yeast as sole source of protein, many investigators have further studied the nutritive value of yeast protein. Plimmer, Rosedale, Raymond & Lowndes [1934], in experiments on chickens, and Mitchell [1924a] in experiments on rats, found that yeast protein, when it is the sole source of nitrogen in the diet, is intermediate in nutritive value between the high value animal proteins and the poorer vegetable proteins; Thomas [1909; 1910], from some experiments carried out on himself, had earlier come to a similar conclusion. Of particular interest are the experiments of Kon & Markuze [1931]; they showed that yeast protein supplements white bread protein in the nutriti'on of the rat. Trials of the value of yeast as a protein concentrate for the feeding of stock animals have all shown it to possess high nutritive-value. For milk production dried brewer's yeast is as good as linseed cake [Barton, Ness & Crampton, 1926], or ground nut cake [Kieferle & Dusch, 1932] or soyabean meal [Biinger, 1934]. In experiments summarized by Bunger [1939] dried cultired yeast (Torula utilis) was found to be but little inferior to fish meal for fattening pigs, when fed with some cereal and potatoes or other root crop. Many other workers have found brewer's yeast,to be a good protein concentrate for pigs. The available information on the value of yeast for egg production and chicken rearing is less accurate but dried yeast appears to be about equal in value to dried skimmed milk. The present experiments were designed to find the value of yeast protein as a supplement for cereal protein. The pig was the experimental animal chosen and maize the cereal. Comparison was made with the value of casein as a supplement for the proteins of whole maize. METHODS The 24 pigs used were of the Large White breed from the pedigree herd of the Agricultural Research Council Field Station, Compton. From the time of weaning until the young pigs attained about 20 kg. body weight they were given a commercial pig feed. They were then divided into eight groups of three pigs each, according to the diets they were to receive. For practical reasons it was not found possible to put all the animals on experiment at the same time; 15 animals were first procured and divided to make up groups 1, 2, 4, 6 and 7; later six pigs were received and these comprised groups 5 and 8; finally, three additional pigs were allocated to group 3. The sex, age at the beginning of the experiment and litter number of all the pigs are included in Table 3. Each group was housed separately in a large loose box which opened into a large uncovered yard. Both box and yard had sloping floors, and, as it was considered unwise to use bedding which the animals might eat, wooden boards were provided on which the animals could lie. The pigs had access to fresh water. The individual method of feeding was employed, the animals being fed to the extent of their appetites morning and evening. To prevent scattering, th...

Nutrition of the bacon pig XV. The relative supplemental value of the proteins in dried brewers' yeast and in white-fish meal

“…It appeared in some instances that just before vomiting started there was excessive salivation, and possibly the vomiting may have been caused by choking from this excess saliva. It is significant to note that similar symptoms were observed by Macrae et al (1942) in their work on fodder yeast already referred to. They state that 'pig 2034 (5% yeast), pig 2168 (10% yeast) and pig 2080 (15 % yeast), were each observed to vomit on one occasion shortly after feeding, while pig 2167 (10 % yeast) vomited on two occasions.These animals may have vomited at other times.'…”

“…Comments on Tables 7 and 8. The white-fish meal Macrae et al (1942) concluded that yeast proteins were not inferior to casein in supplementing the proteins in maize meal, and the results of the present trial confirm the high biological value, when yeast is incorporated in a barley meal-fine bran diet, for young pigs.…”

“…Some continental authorities believe, however, that only 50 % of the normal supply of protein in the diet of young pigs can be supplied in the form of dried yeast without impairing the rate of live-weight gain. Macrae, El-Sadr & Sellers (1942) investigated the value of yeast in comparison with casein for supplementing a maize-rich cereal ration when fed to bacon pigs. Macrae was led to the choice of maize meal as the major cereal ingredient of the diet by the fact that maize proteins, particularly zein, are considered to have a low biological value even among the cereals.…”

Effect of Cyberlindnera jadinii yeast as a protein source on intestinal microbiota and butyrate levels in post-weaning piglets

“…Sustainable protein alternatives are needed to reduce the dependency on soy and other conventional proteins as ingredients in the feed for animal husbandry. As early as in the 1940’s, researchers pursued the idea of replacing a substantial fraction of protein in animal feed with proteins from yeast derivatives [ 2 , 3 ]. It soon became apparent that the lack of cost efficient methods for large scale yeast production would limit the use of yeast proteins [ 3 ].…”

Section D. The Nutritional Value of Milk and Milk Products

“…A marked supplementary effect of casein on the biological value of maize proteins for young growing pigs has been reported by Macrae et al (259).…”