본 연구는 치어기 잉어에 있어서 어분 (fish meal, FM) 대체단백질원으로서 lysine 부산물 (lysine cell mass, LCM)이 사료내 이용 가능성과 대체 수준을 결정하기 위해 수행하였다. 실험사료의 조단백질 함량은 38%, 가용에너지는 15.2kJ/g (protein, carbohydrate and lipid: 16.7, 16.7 and 31.7 kJ/g)으로 동일하게 맞추어 실험사료를 제조하였으며, 사료의 조성을 요약하면 다음과 같다: LCM_0, 100% FM; LCM_20 80% FM+20% LCM; LCM_40, 60% FM+40% LCM; LCM_60 40% FM+60% LCM; LCM_100 100% LCM; LCM_20ℓ, 80% FM+20% LCM+0.07% Lysine; LCM_40ℓ, 60% FM+40% LCM+0.14% Lysine; LCM_60ℓ, 40% FM+60% LCM+0.22% Lysine; LCM_100ℓ, 100% LCM+0.35% Lysine. 6주 동안의 실험 결과, 증체율, 사료효율, 일간성장률, 간중량지수 및 단백질전환효율에 있어서 LCM_0와 비교하여 LCM_20는 유의적인 차이가 없는 반면에 (P>0.05), LCM_40, LCM_60 및 LCM_100, LCM_40ℓ, LCM_60ℓ 및 LCM_100ℓ는 유의적으로 낮게 나타났다 (P<0.05). LCM_0와 LCM_20ℓ은 증체율, 일간성장률, 간중량지수 및 단백질 전환효율에 있어서는 유의적인 차이를 보이지 않는 반면에 (P>0.05), 사료효율에 있어서는 LCM_0에 비해 LCM_20ℓ이 유의적으로 낮게 나타났다 (P<0.05). 헤마토그리트과 비만도는 모든 사료구에서 유의적인 차이가 없었다 (P>0.05). 따라서, 치어기 잉어에 있어서 lysine 부산물은 어분단백질의 20%까지 대체 가능하며, lysine 부산물에 결핍된 필수아미노산인 lysine을 첨가한 사료구애서는 첨가 효과가 나타나지 않았다.

This experiment was conducted to evaluate the lysine cell mass (LCM) as a dietary fish meal (FM) protein replacer in juvenile Israeli carp, Cyprinus carpio. Fishmeal, a major animal protein source in the control diet, was replaced by LCM on the protein equivalent base. Fish averaging 1.7±0.1 g (Mean±SD) fed one of nine diets containing isonitrogenous and isocaloric basis of 38% crude protein and 15.2 kJ available energy/g diet: control, 100% FM; LCM_20 80% FM+20% LCM; LCM_40, 60% FM+40% LCM; LCM_60, 40% FM+60% LCM; LCM_100 100% LCM; LCM_20ℓ, 80% FM+20% LCM+0.07% Lysine; LCM_40ℓ, 60% FM+40% LCM+0.14% Lysine; LCM_60ℓ, 40% FM+60% LCM+0.22% Lysine; LCM_100ℓ, 100% LCM+0.35% Lysine. After 6 weeks of feeding trial, there was no significant difference in weight gain (WG), feed efficiency (FE), protein efficiency ratio (PER) and specific growth rate (SGR) among fish fed control and LCM_20 (P>0.05), while fish fed LCM_40, LCM_60, LCM_100, LCM_40ℓ, LCM_60ℓ and LCM_100ℓ diets had a significantly lower WG, FE, PER and SGR than did fish fed control diet (P<0.05). There was no significant difference in WG, PER and SGR among fish fed control and LCM_20ℓ diets (P>0.05), while fish fed LCM_20ℓ had a significantly lower FE than did fish fed control diet (P<0.05). No significant difference was observed in hematocrit and condition factor among fish fed nine diets (P>0.05). Therefore, these results indicated that LCM could replace FM up to 20% and dietary synthetic lysine supplementation did not show any positive growth effects in juvenile Israeli carp.