Ki Wook Lee

Effect of the Formulated Diets on Performance and Resistance of Juvenile Abalone [Haliotis discus (Reeve, 1846)] Subjected to Various Stress Conditions

ABSTRACT Performance and stress resistance of juvenile abalone (Haliotis discus) fed formulated diets substituting fish meal (FM) and macroalgae (MA) with soybean meal and rice bran, respectively, was compared with the MA under various stress conditions. Four experimental diets (Standard, FM50, FM50 + MA50, and FM50 + MA100 diets) were prepared in duplicate. The dry MA (Undaria pinnatifida and Laminaria japonica)were also prepared to compare with the effects of formulated diets on the performance of abalone to achieve the industry standard. About 84,000 juvenile abalone were distributed into twelve 5-ton tanks (7,000 abalone per tank). The diets were fed to abalone once a day to satiation. At the end of the 16-wk feeding trial, abalone were subjected to various stress (air exposure, sudden salinity, and temperature changes) conditions and cumulative mortality was monitored. Weight gain and specific growth rate of abalone fed the all formulated diets were higher than the dry MA. The cumulative mortality of abalone fed the MA was higher than that of abalone fed the all formulated diets at the end of observation after sudden salinity and temperature changes. In conclusion, the well-formulated diets produced better growth performance of abalone over the dry MA. Abalone subjected to the various stress conditions after being fed with all formulated diets, except for abalone fed with the Standard, FM50, and FM50 + MA50 diets after air exposure, were more resistant than those fed the MA.

Effects of Dietary Carbohydrate Sources on Growth and Body Composition of Juvenile Abalone (Haliotis discus, Reeve)

ABSTRACT A 16-wk feeding trial was conducted to assess the effects of different types of dietary carbohydrate on growth and body composition of juvenile abalone (Haliotis discus). A total of 1,680 abalone were randomly distributed among 24 containers (70 per container) and fed one of eight diets, including seven experimental diets containing different types of carbohydrates, including dextrin (DT), glucose (GC), corn starch (CS), α-cellulose (CL), maltose (MT), sucrose (SC), and wheat flour (WF), and Undaria to compare effect of experimental diets. Water stability of the diets was measured 12, 24, and 48 h after seawater immersion. Water stability of the diets was different over all periods of time and their significant interaction was also observed. Survival was not significantly affected by diet. Weight gain and specific growth rate were greatest in abalone fed on the CL diet. Shell length, width, height, and soft body weight were greatest in abalone fed the CL diet, followed by the WF, DT, SC, CS, GC, and MT diets and Undaria. Weight gain, specific growth rate, crude protein, and crude lipid contents of the soft body of abalone fed on the experimental diets were greater than those fed on Undaria. This study shows that CL is the most effective carbohydrate source for improving growth of this species of juvenile abalone and practically applicable in formulating abalone feed.

Effect of Dietary Additives on Growth, Feed Utilization, and Body Composition of Juvenile Rockfish Sebastes schlegeli

국내 어류양식 산업은 해양 환경의 급변화와 빈번하게 발생하 는 질병 발생 등으로 인한 대량폐사 때문에 양식 어민들의 경제 적 손실은 아주 심각한 실정이며, 이러한 대량폐사를 감소시키 기 위한 목적의 양어용 사료첨가제 개발은 지속적으로 많은 연 구자들의 관심 대상이 되고 있다(Ji et al., 2007b; Gabor et al., 2010; Bulfon et al., 2015). 그러나 양식중인 어류의 대량폐사를 감소시키기 위한 목적의 사료내 합성항산화제나 합성항생제의 사용은 이들 물질의 어체 내 잔류, 환경오염 및 식품으로서의 안전성 위협 등의 문제를 야 기시킬 수 있기 때문에 유럽의 몇몇 나라에서는 이들의 사용을 전면 금지하고 있으며(Tang et al., 2001), 우리나라에서도 사료 회사에서 양어용 배합사료를 생산할 때에는 합성항생제(동물 용 의약품)를 사용하지 못하도록 법규로 규정하고 있는 실정이 다. 따라서 어류의 양식생산양 증대를 위해서는 이들 합성항산 화제나 합성항생제를 대체할 수 있는 새로운 천연 소재의 식품 으로서도 안전한 사료첨가제의 개발이 지속적으로 이루어져야 한다. 특히 양어용 배합사료내 항생제 대체원으로서 약용 식 물의 적용에 최근 전세계적으로 많은 연구자들의 관심이 모아 지고 있다(Jeney et al., 2009; Gabor et al., 2010; Chakraborty and Hancz, 2011; Harikrishnan et al., 2011). 해산어류용 배합사료내 면역성(내병성) 향상의 목적으로 개발한 천연 소재의 사료첨가제[인도산 약용 식물(Ocimum sanctum와 Withania somnifera의 메탄 추출 농축액), 약용 식 물(Massa medicate, Crataegi fructus, Artemisia capillaries 와 Cnidium officinale) 또는 이들 4종류의 혼합물, 인도산 약 용 식물[Cynodon dactylon, Piper longum, Phyllanthus niruri, 배합사료내 사료첨가제가 조피볼락(Sebastes schlegeli) 치어의 성장, 사료 이용성 및 체조성에 미치는 영향