Journal of The School of Marine Science and Technology,Vol.2 No.3
Histological Observations of Intestinal Degeneration of Defatted Soybean
Meal Diet and Supplemental Effect of Soybean Lecithin for Fingerling
Rainbow Trout, Oncorhynchus mykiss
Nobuhiro SUZUKI and Takeshi YAMAMOTO
Abstract
The feasibility of defatted soybean meal (SBM) based non-fish meal diets for fingerling rainbow trout
Oncorhynhcus mykiss was investigated.A control diet composed mainly of fish meal and non-fish meal diet composed
mainly of SBM and SBM supplemented with 3% of commercial soybean lecithin were fed to the rainbow trout
(10.4±0.2g in Body weight)for10weeks at water temperature of16±1°C.Essential amino acids were supplemented
to the non-fish meal diets to attain the levels of the fish meal diet. The fish meal diet showed the best growth and
protein utilization and lecithin supplementation had no positive effect on the growth and protein utilization.Although
intestine of fish fed the SBM diet showed fatty degeneration, intestine of fish fed the SBM supplemented with 3%
of commercial soybean lecithin showed no fatty degeneration.These results suggest that supplementation of lecithin
at 3% to the SBM based non-fish meal diet is effective to improve digestion and absorption of fatty substance as
polar lipids.