EFFECT OF DIETARY PROTEIN LEVELS ON GROWTH HORMONE (GH) LEVELS AND GROWTH RATE OF OREOCHROMIS NILOTICUS

EFFECT OF DIETARY PROTEIN LEVELS ON GROWTH HORMONE
(GH) LEVELS AND GROWTH RATE OF OREOCHROMIS NILOTICUS
BY
ABDALLA, A. EI-SHEBLY
National Institute ojOceanography andfisheries
ABSTRACT
Fingerlings Nile tilapia, Oreochromis niloticus (average weight of21.8
gmlfish) were raised in glass aquaria for 80 days under controlled
laboratory conditions. GH and growth rate of Oreochromis niloticus fed
on 2 diets of different protein levels (15 % and 25 %) were studied in
comparison with the control (without feeding). The results showed an
increase in growth rate and GH in Oreochromis niloticus with increasing
protein levels and a decrease in un-ftd one. Amounts ofprotein andfat in
Oreochromis niloticus muscles were studied. It was found that the amounts
of protein and lipid in muscles varied directly with the percentage of
protein in food. The highest growth hormone levels were obtained with 25
% protein diet and the lowest were recorded in the control one (without
feeding).