배합사료내 농수산부산물의 해조류 대체에 따른 까막전복 치패의 성장과 체조성에 관한 연구

Abstract

Macroalgae (MA) is one of the highest and expensive components in formulating abalone (Haliotis spp.) feed. Therefore, looking for an alternative source for MA is of great interest for scientists worldwide. A couple of the experiments was performed to evaluate substitutability of residues of citrus juice product (RCJP) and different parts (stem, sporophyll, root and the combined stem, sporophyll and root) of Undaria pinnatifida for MA in abalone feeds. In the experiment 1, dietary substitution effect of Saccharina japonica with residues of citrus juice production (RCJP) on the growth and body composition of abalone (H. discus) subjected to air exposure was determined. A total of 1,260 abalone was randomly distributed into 18 net cages (seventy abalone per cage). Five formulated diets were prepared. The control (RCJP0) diet included 20% S. japonica. Twenty five, fifty, seventy five, and one hundred percent of S. japonica were substituted with the same amount of RCJP, referred to as the RCJP25, RCJP50, RCJP75, and RCJP100 diets, respectively. Finally, dry S. japonica was prepared to compare the formulated diets on growth performance of abalone. Each diet was randomly assigned to triplicate groups of abalone. Abalone was daily fed to satiety with little leftover for 16 weeks. After the 16-week feeding trial, abalone was subjected to air exposure stressor for 20 h, and then survival was monitored for the next 120 h. All formulated diets achieved significantly greater weight gain and specific growth rate (SGR) than those of abalone fed the S. japonica. Weight gain and SGR of abalone linearly improved with the increased substitution levels of S. japonica with RCJP in feeds. The greatest weight gain and SGR were obtained in abalone fed the RCJP100 diet. The shell growth and soft body weight of abalone also linearly increased with dietary substitution levels of S. japonica with RCJP. The chemical composition of the soft body of abalone was not affected by the experimental diets. Survival of abalone fed all formulated diets, except for the RCJP0 diet was significantly higher than that of abalone fed the S. japonica at the end of the 120-h post observation. S. japonica could be completely (100%) replaced with RCJP in formulated diet for abalone. The greatest growth performance was obtained in abalone fed the RCJP100 diet. In the experiment 2, substitution effect of different parts of U. pinnatifida in diets on the growth and chemical composition of juvenile abalone (H. discus) was determined. A total of 1,050 juvenile abalones was randomly distributed into 15 plastic container. Five formulated diets were prepared. The control diets (Con) included 15% U. pinnatifida powder. The stem, sporophyll and root of U. pinnatifida, and their combination were included instead of U. pinnatifida powder in the Con diet, referred to as the Stem, Sporophyll, Root, and CSSR diets, respectively. Each diet was assigned to triplicate groups of abalone, and fed to abalone once a day to satiety with little leftover for 16 weeks. Weight gain and SGR of abalone fed the Con diet were significantly greater than those of abalone fed all other (Stem, Sporophyll, Root and CSSR) diets. Shell length of abalone fed the Con diet was significantly longer than that of abalone fed the Stem and Sporophyll, but not significantly different from that of abalone fed the Root and CSSR diets. Shell width and height and the soft body, and the ratio of soft body weight to total weight of abalone tended to agree with growth rate. The chemical composition of the soft body of abalone was not affected by the experimental diets. Growth performance (weight gain and SGR) of abalone fed the Con diet was greater than that of abalone fed all other diets indicated that substitutability of different parts of U. pinnatifida, such as stem, sporophyll and root of U. pinnatifida and their combination for U. pinnatifida powder in abalone feed was very limited. In conclusion, 100% S. japonica could be replaced with RCJP in abalone (H. discus) feed in the experiment 1, but substitutability of different parts of U. pinnatifida for U. pinnatifida powder in the experiment 2 seemed to be very limited.