Kiyoshi ABE2), Etsuro KUWAHARA3), Junichi YAMADA3) Kensaku ITO3) 1) Gifu Prefectural Poultry Breeding Station, Seki-shi, 501-32 2) Mie Prefectural Agricultural Technical Center, Ichishi-gun, Ureshino-cho, 515-22 3) Shizuoka Prefectural Poultry Experiment Station, Kakegawashi, 436-02 Several reports1-9) have been available on the value of microbial proteins as feedstuffs. According to these reports, the crude protein contents of such materials of microbial origin range from 50 to 56% for methanol-utilizing, ethanol-utilizing and brewers yeasts, and over 70% for methanol-utilizing bacteria1). It was demonstrated that the protein value of these materials were increased to 80 or more by the addition of DL-methionine2), and these materials had a high energy value and featured high phosphorus-availability1). However, microbial proteins are deficient in Ca1), Se3) and methionine5), while sulfur-containing amino acids such as methionine and cystine have been shown to be the first-limiting amino acids2,6). ABBEY et al, and D'MELLO have each conducted a series of experiments with amino acids added to methanol-utilizing bacteria7-9). The results of these investigations suggested the utility of microbial proteins as protein sources in poultry feeds. These proteins have not been utilized as feedstuffs in Japan. It is necessary to study the nutritive values and safety of these proteins to chickens, and the palatability and safety to man of the eggs and meat from the birds so fed. The values of these new feed materials, and the effects on the health of chickens and their offsprings, were examined by YOSHIDA et al. using hydrocarbon-utilizing yeasts10-14). Further experiments by the same group formed the basis for a standardised protocol for the evaluation of new protein sources. This has been repeated in the present series of experiments which investigated the possibility of exploiting protein from methanol-utilizing bacteria (SCP), as a feed using the same techniques employed with experiments made to test hydrocarbon yeasts (YOSHIDA et al. 15,16)). The study consisted of a lifetime (212-week) feeding trial, a three-generation feeding trial (One generation is 68 weeks), and a 6-generation feeding trial (One generation is 36 weeks), together with a total of 23 hatchability tests. The study encompassed investigations
