Effects of dietary energy with iso-protein level on growth and body composition of tilapia

Abstract

Tilapia juveniles (Oreochromis aureus) were fed with three different diets which contained 32% of protein with three different energy levels, 260, 316 and 342 Kcal/100g, respectively. The experiment was conducted in four replicates for each diet for the period of 6 weeks. The results indicated that the mean fish weight, protein efficiency ratio (PER), percentage of protein retained and energy retained and fish fat increased with the increase of energy level in the diets, but the feed conversion ratio (FCR), percentage of fat retained and fish moisture decreased with the increase of energy level in the diets. Increasing the energy level from 260 to 316 and 342 Kcal/100g could have protein sparing effect of 16.2% and 24.6%.以酪蛋白(Casein)為蛋白源調製3種蛋白質含量同樣為32%，而能量分別為260，316及342kcal/100g之飼料來飼育吳郭魚(O. aureus)，為期6週，每種飼料皆進行4個重複試驗。試驗結果顯示平均魚體重、蛋白質效率(Protein Efficiency Ratio, PER)、蛋白質蓄積率、能量蓄積率及魚體脂肪含量均随能量增加而增加；而飼料轉換效率(Feed Conversion Ratio, FCR)、脂肪蓄積率及魚體水分含量则隨能量增加而降低，根據魚體成長及蛋白質蓄積率之結果看來，在飼料蛋白質含量32%時之最適蛋白能量比(P/E ratio)在101mg/kcal左右，將飼料能量增加56及82 kcal/100g，则分別有16.2%及24.6%之蛋白質節約效果。