Abstract
In order to investigate the effects of phosphorus and iron levels in the diets containing fish meal as only protein source on the growth, feed conversion, body composition and blood characteristics of juvenile Korean rockfish, either graded monobasic potassium phosphate (MPP) of 1% (MPP-1), 2% (MPP-2), 3% (MPP-3) and 4% (MPP-4), or Fe-citrate (FC) of 0.022% (FC-1), 0.044% (FC-2), 0.066% (FC-3) and 0.088% (FC-4) was added to fish meal-based diet (MMP-0 or FC-0), respectively. Duplicate groups of 40 fish weighing 7g were fed the diets for 21 weeks. Weight gain, feed efficiency and nutrient retention of fish fed diets with different MPP levels were not significantly different (P>0.05). Lipid content of whole body decreased with an increase in dietary MMP (P<0.05). No significant differences were found in the Ht, Hb, total protein, or total glucose in serum among diets containing different MMP levels (P>0.05). Weight gain of fish fed the FC-0, FC-1 adn FC-3 diets was significantly higher than that of FC-4 diet (P>0.05), whereas feed efficiency, nutrient retention, hematological values (Ht, Hb, total protein, and total glucose), and whole body composition were not affected by dietary FC levels (P>0.05). The present results revealed that phosphate or iron supplementation to the diet containing 65% fish meal for juvenile Koran rockfish was not necessary.
어분이 65% 첨가된 사료에 P와 Fe의 보충 효과를 조사하기 위해 인산염($KH_2PO_4$)을 0%, 1%, 2%, 3% 및 4% 첨가한 사료와 철 (Fe-citrate)을 0.022%, 0.044%, 0.066% 및 0.088% 첨가한 실험사료를 설계, 제조하여 조피볼락 치어 (평균 체중 7 g)를 각 수조 ($100\ell$)에 40마리씩 2반복으로 수용하여 각각 21주간 사육실험하였다. 사육실험 결과, 증체율, 사료효율, 영양소축적율, 혈액성상 사료의 P 첨가량에 따른 유의적인 차이가 인정되지 않았다(P>0.05). 조지방의 경우는 사료의 P 함량이 높을수록 감소하여 유의적으로 낮은 값을 보였다(P<0.05). Fe 보충효과 실험에서, 증체율, 사료효율, 영양소축적율, 혈액성상 및 전어체의 일반성분은 Fe를 보충하여도 개선되지 않았으며, 성장률은 오히려 Fe 첨가량이 높은 실험구에서 저하되는 현상을 보였다. 따라서 조피볼락 사료에 어분이 65% 배합될 경우에는 별도의 P와 Fe 첨가는 필요 없을 것으로 판단된다.
