Abstract:
The cell mass of photosynthetic bacteria cultivated on pineapple waste medium (total sugar ca. 100 g/1) under microaerobic-dark condition in 300 lit fermenter was used throughout this study. The cell mass was deep red and contained 82% moisture content. Preliminary feeding trial was investigated in 3-month old fancy carps by replacing the fresh cell of photosynthetic bacteria for 50 and 100% of fish meal in control diet (about 6.8 and 13.6% dry wt. basis). The results showed that the skin pigmentation of fish fed with bacterial cell-substituted diet increased significantly 4 and 2 weeks after culture (at 5% level significant). To investigate the stability in water of bacterial cell-substituted pellet was found 7.5% of alpha starch was optimal for stability in both still and flow water. In addition, optimal temperature for drying pellet was found to be 60 and 70℃ with 4.00 and 3.00 hours incubation respectively. The selected temperatures were the range which least decresed the carotenoid content of the pellet. The feeding experiment in 3-month old fancy carps was found that the pellet substituted with cell mass 6.8 and 10.2% were increased the skin pigmentation of the fish after 6 and 4 weeks cultivation (statistically different 5% level). Studies on shelf life of the bacterial cell-substituted and dried pellet in polyethylene plastic bag showed that the diet could be stored at room temperature for 60 days without any microbial spoilage.