Effects of dietary protein and energy on growth, feed conversion efficiency and body composition of Tilapia aurea.
The optimum dietary protein to energy (P:E) ratio for rapid and efficient gain of juvenile Tilapia aurea was shown to fall with increasing size of fish. The optimum concentration of protein and energy also fell with growth. A diet providing roughly 56% protein at 4,600 kcal/kg digestible energy (gross energy adjusted for indigestible fiber) with a P:E ratio of 123 mg potential/kcal produced highest gains of fry (2.5 g). Larger fish (7.5 g) grew most rapidly when fed a 34% protein, 3,200 kcal/kg diet with a P:E ratio of 108. Apparent feed conversion (grams of feed offered/grams of fish weight gain) was superior on diets having lower P:E ratios and was best on the 34% protein, 3,200 kcal/kg diet. Linear regression analysis indicated highly significant differences in average fish weight, condition [10(5) x weight (g)/total length (mm)3], and feed conversion efficiency attributable to changes in either protein or energy concentration. Significant interaction between protein and energy was also demonstrated. Condition and level of carcass fat were high on all diets which produced good growth rates and were inversely related to P:E ratio. Moisture and ash were inversely related to carcass fat. No trend was established for carcass protein.
D000818:Animals; D001823:Body Composition; D001834:Body Water / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000494:pharmacology*; D002149:Energy Intake; D005399:Fishes / Q000502:physiology*; D006128:Growth; D050356:Lipid Metabolism; D011506:Proteins / Q000378:metabolism
D004044:Dietary Proteins; D011506:Proteins