魚類における食じ脂質の栄養価 ＸＶＩ コイ用飼料におけるエネルギー源としての炭水化物と脂質

Abstract

Feeding experiments were conducted in order to compare the availability of carbohydrate with that of lipid as dietary energy sources for carp. The fish were fed various diets containing different amounts of carbohydrate and lipid at a fixed protein level of 32%. The results showed that carp utilize effectively both carbohydrate and lipid as dietary energy sources. The enrichment of the digestible energy (DE) content from 320-460 kcal/100g diet by the addition of lipid at levels of 5% to 15% to diets resulted in no improvement in growth, feed conversion, or the value for NPU. The digestibility of protein and carbohydrate was as high as 95% and 85%, respectively, regardless of the contents of carbohydrate, lipid, and energy in the diets. The lower the lipid content or the higher the carbohydrate content in the diets, the higher the retention rate of lipid was obtained. It has thus been shown that both carbohydrate and lipid have good food value for carp as dietary energy sources. The growth and the value for NPU were not affected by the DE contents, even enriched by using carbohydrates or lipids, when the dietary protein levels remained around 32%.