| Summary: | 碩士 === 臺灣大學 === 漁業科學研究所 === 95 === To gather the information for the development of less P loading diets through the combination of alternate protein sources that provide a more available P source for red striped snapper（Lutjanus erythropterus）, two trials on the diets of juvenile snappers with reducing phosphorus (P) loading are studied. This research was conducted to investigate the effects of supplementary inorganic phosphate in mineral mixture. Growth performance, feed efficiency, P concentration of vertebrae were compared between duplicate groups of fish reared with control diet formulated with 60% fish meal. The experimental diets were formulated with non-fish meal（first trial）and low level of fish meal (FM, 10%) （second trial）,and both of these diets contained the low-P ingredients－squid meal (7.5%), lupin meal (20%), corn gluten meal (20%),and rapeseed meal(10%).
In the first trial, Some or all of the compositions－NaH2PO4, KH2PO4, Ca(H2PO4)2 in 5% mineral premixture were eliminated in most of the diets, and some were supplied with graded Ca(H2PO4)2（15, 20, 25, 30%）in 5% mineral premixture, respectively. These diets were fed to juvenile snapper (8.88g) for 42 days. The results showed the optimal phosphorus（P） level of the diet was 1.68-1.88%.
In the second trial, control and experimental diets formulated with animal and vegetative ingredients were fed to juvenile snapper (8.09g) for 56 days. One of the experimental diets was mainly formulated with 60% fish meal, and not added with any mineral; four of those were added with 10% fish meal, and also varied in the amount of phosphate in mineral mixture. The results showed the optimal P level of the diet was 1.78%.
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