Accumulation of the Conjugated Linoleic Aacid (CLA) in Tilapia ( Tilapia nilotica) Fed Diets on Various Levels of CLA

CLA (Conjugated linoleic acid) 급이수준에 따른 역돔의 CLA 축적량

Effects of conjugated linoleic acid (CLA), known as an effective anticarcinogen in several animal models, on the tilapia were investigated. The CLA was made from safflower oil by alkaline isomerization method. Isomers in CLA such as cis-9, trans-11 and trans-10, cis-12 occupied over $80\%$, and other isomers was below $20\%$. In experiment, 250 fishes (average weight is 32 g) were divided into 15 fishes per five treatment and triplicate group for 8 weeks: control, $1\%$ CLA, $2.5\%$ CLA, $5.0\%$ CLA, and $10\%$ CLA diets. Daily growth rate and feed coefficiency were measured every week. The most effective diet for the growth rate and feed coefficiency of tilapia was $1.0\%$ CLA diet group. Every two weeks, sampled and determined the contents of CLA in the muscle and liver, After 8 weeks, $1.0\%$ and $10.0\%$ of CLA fed group accumulated the CLA as 41.3 and 180.9 mg/g of fat in their muscle respectively, Also, n-9 and n-3 fatty acid (FA) compositions were almost not changed in the muscle and liver. But n-6 fatty acid was changed according to the contents of fed CLA. The $1.0\%$ CLA fed group was shown the highest contents of n-6 FA and the $10.0\%$ CLA group was shown the lowest contents of n-6 FA.

기능성물질인 CLA를 양어사료에 첨가하여 기존의 어류와는 다른 기능성 역돔 생산을 시도하였다. 사육 8주간 매 2주마다 어체내의 CLA축적도를 측정한 결과 8주 후 $1\%$ CLA 첨가구에서는 41.3 mg/g of fat였으며, $10\%$ CLA 첨가구에서는 180.9mg/g of fat으로 역돔의 정상적인 성장을 고려하지 않는다면 $10\%$의 사료내 첨가도 가능한 것으로 생각된다. 그러나 정상적인 성장을 고려하면 CLA의 적정 첨가량은 $1\%$로 나타났으며, 그 이상의 첨가시에는 성장 저하 현상을 나타내었다. 합성된 CLA는 총 6 종류의 이성체로 구성되어 있었고, 그 중 c9, t11 및 t10, c12 이성체가 $85\sim90\%$를 이루고 있었으며, 첨가된 CLA 함량에 따라 축적되는 양도 달라졌다. 사육 8주 후, 육 및 간 중의 지방산 조성은 n-9, 3 계열은 거의 화를 나타내지 않았으나, n-6계열은 첨가된 CLA의 함량에 따라 육 및 간에 축적되는 양은 $5\sim27\%$로, $1\%$ CLA 첨가구가 가장 높았고, $10\%$ CLA 첨가구가 가장 낮은 함량비를 나타내었다.