| Abstract;In order to progress dietary yeast utilization for red sea bream, Pagrus major, dried eighteen yeasts were prepared for preference and rearing tests. The fish weighing 6.4-10 g on initial mean body weights were fed diets including 30% of each yeast to apparent satiation for 7 days. Endomyces lindneri, Rhodotorula rubra and Galactomyces ressii promoted, but Trichosporon cutaneum, Hansenula anomala and Torulopsis candida suppressed the feeding activity of the fish. Saccharomyces cerevisiae, Hansenula silvicola, Kluyveromyces marxianus, Hyphopichia burtonii, Rhodotorula glutinis, Saccharomyces lypolitica, Debaryomyces membranaefaciens, Schizosaccharomyces pombe, Torulopsis aeria, Pichia kluyveri and Saccharomyces ludwigii did not affect on the feeding activity as compared with brown fish meal. The fish weighing 5.0 g on an initial mean body weight were fed diets including 0, 20, and 40% R. rubra as a yeast protein (YP) for 42 days. No significant differences among dietary YP treatments were found in survival, final carcass proximate composition, and gastral organ weight. Daily feed intake, enteral organ weight, and aerobic microbial count of whole gut showed increasing trends with an increase in dietary YP. Otherwise, weight gain, feed efficiency (FE), protein efficiency ratio (PER), apparent protein and fat retentions, and hepato-somatic index, all appeared decreasing trends with an increase in dietary YP. Although, FE and PER of 20 and 40% YP diet groups were lower than 0% YP diet groups. These results suggest that red sea bream appear various degrees of palatability for dietary yeasts and that yeasts are probably available dietary proteins for fish diet. (author abst.) |
