Comparisons of single moist pellet and mainly-raw-fish moist pellet on the growth, feed efficiency, and protein digestibility of yellowtail in low temperature period

摘要

In order to investigate the growth performance of formula feed(mash type) on the growth, feed efficiency, and protein digestibility of yellowtail, Seriola quinqueradiata, in low temperature period, the fish were reared on three different diets, 1) a single moist pellet diet (SMP), 2) a protease-treated single-moist-pellet fish meal (E-SMP), and 3) a mainly-raw-fish moist pellet diet (RF-MP) for 130 days from October to February. Growth, feed efficiency, and protein efficiency ratio were the highest in fish fed RF-MP; E-SMP gave higher values than SMP. Although pepsin-like and trypsin-like activities were the lowest in fish fed RF-MP, protein digestibility was the highest in fish fed RF-MP, and it was slightly higher in fish fed E-SMP than SMP. These results indicated that the growth performance of the fish fed the formula feed was lower than that fed RF-MP in low temperature period. This was thought that lower water tempareture directly decreased protein digestibility of formula feed although fish increased their digestive enzyme activities to adopt the formula feed.