Improved carp [Cyprinus carpio] diets based on plant protein sources reduce environmental phosphorus loading
2003
Jahan, P. (Tokyo Univ. of Fisheries (Japan)) | Watanabe, T. | Kiron, V. | Satoh, S.
ABSTRACT: As part of on-going efforts to reduce environmental phosphorus (P) and nitrogen (N) loading from culture systems, five experimental diets were formulated containing 5-15% of fish meal (FM) and different levels of soy protein concentrate (10-20%), corn gluten meal (3-5%) and defatted soybean meal (2.0-8.5%). These diets had total P ranging between 1.04 and 1.29% and available P between 0.62 and 0.63%. A FM-based (43%) commercial diet was used as the control and this diet had total P of 1.87% and available P of 0.82%. Waste loading was calculated after feeding the diets to 3.4 g carp for 10 weeks. Feed gain ratios were not significantly different for fish fed control and experimental diets having 10-15% FM, but the protein efficiency ratio was lower for the control group. The rates of P absorption and retention in the experimental diet groups were significantly higher than those of the control group. The lowest N retention was obtained for the control group, although absorption was not markedly different among the treatment groups. Total P and N loading (kg/ton production) produced from the experimental diets ranged from 7.1 to 8.9 and from 36.1 to 41.3, respectively, whereas the corresponding values for the control diet were 15.2 and 48.1.
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