GROWTH PERFORMANCE, NON-SPECIFIC IMMUN AND ANTIOXIDANT RESPONSE OF JUVENILE TILAPIA OREOCROMIS SP. FEEDING ON BREWER’S YEAST SACCHAROMYCES CEREVISIAE SUPPLEMENTED DIET

Abstract

A triplicate experiment was conducted to evaluate the effect of the diet suplemented with brewer's yeast on
the growth performance and imune response of nila tilapia Oreocromis sp. Five isonitrogenous (30% crude
protein) and isocaloric diets were used in this experiments. As a control, the diet 1 were formulated without any
suplementation of glucan and brewer’s yeast; while those diets 2-5 were suplemented with either 0.3% glucan,
3.5% brewer’s yeast, 17.5% brewer’s yeast, and 35% brewer’s yeast respectively. One hundred fish with an
initial body weight of 2.4±0.10g were cultured in 2x1x1x1m3 of floating net cages. The fish were fed on the
diets at satiation for 6 weeks. At the end of feeding experiment, 20 fish from each net cage were trasferred in to
35x35x40 cm3 of aquarium to perform a challenge test with patogen bacteria Streptococcus agalctiae. Results
showed that fish fed on control, 0.3% glucan and 3.5% brewer’s yeast supplemented diets significanly had higer
growth rate, feed conversion ratio, and protein retention than others. It was also found that superoxide dismutase
(SOD) activity of fish was increased when feeding on the diets suplemented with glucan and brewer’s yeast. On
the other hand, glutathione peroxidase (GPx) activity decresed and lipid peroxidation increased in the group of
fish on the diets suplemented with 17.5% and 35% of brewer’s yeast. While, the group of fish in 0.3% glucan
and 3.5% brewer’s yeast treatment had higer number of total erythrocytes hemoglobin, hematocrite, leukocyte,
monocyte as well as phagocytic and lysozyme activities. The fish survival after 12 days challenge test was
significantly higer in 0.3% glucan and 3.5% brewer’s yeast teratment. Thus feeding on the diets suplemented
with glucan and 3.5% berewer’s yeast could increase the immune response of tilapia by increasing non-specific
response of fish phathogen.