Optimum level of dietary monocalcium phosphate based on growth and phosphorus excretion of mirror carp, Cyprinus carpio

초록

Triplicate groups of mirror carp were reared with experimental diets containing practical ingredients with graded levels of monocalcium phosphate (MCP: 0, 1, 2, 3, 4, and 5%) for 8 weeks. Seventy carp weighing 18 g fish(-1) were allotted in each tank of 130 1 maintained at 26-28 degrees C. Fish were fed 3 times daily to apparent satiety by hand. The lowest growth was observed in fish fed the basal diet without MCP, in which the available phosphorus (P) was determined to be 0.24%. Fish fed the diet containing 2% of MCP (available P of 0.67%) showed the best performance in weight gain (44 g), feed conversion ratio (1.02) and protein efficiency ratio (2.33). P gain (0.15 g fish(-1)) was constantly maintained regardless of difference in P intake. The best results in terms of P loss (13 g kg(-1) gain) and P retention efficiency (23.4%) were observed in fish fed the diet containing 1% MCP (available P of 0.42%), which were, however, not different(P > 0.05) from those of fish fed the diet containing 2% MCP, On the other hand, fish fed the latter diet excreted the least nitrogen (44 g kg(-1) gain) and showed the highest nitrogen retention efficiency (35.6%). The present results indicate that a dietary level of 0.7% available P will provide for both maximal growth and minimum P loss in juvenile carp. (C) 1998 Elsevier Science B.V.

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