EFFECTS OF RAFFINOSE ON GROWTH PERFORMANCE, IMMUNITY, STRESS|RESPONSE AND SURVIVAL OF JAPANESE SEABASS(LATEOLABRAX|JAPONICUS)CHALLENGED WITH AEROMONAS HYDROPHILA

A 16w growth trial was conducted to study the effects of raffinose on growth performance, non-specific immunity,stress response and survival of Japanese seabass (Lateolabrax japonicus) challenged with pathogenic bacteria,Aeromonas hydrophila in a recirculation system. Five experimental diets with 0, 200, 400, 800 and 2000 mg/kg of raffinosesupplements were prepared, and named as R0, R200, R400, R800 and R2000, respectively. Each diet was fed totriplicates groups of Japanese seabass (initial body weight: average of 3g), with 30 fish in each tank. At the end of trial,fish were weighed and serum sample were collected. Besides, a 30s air-exposure stress test and a challenge test with A.hydrophila were carried out.Survival and feed intake of fish did not show significant difference among all groups (P0.05). Weight gain rate(WGR) of R800 group was significantly higher than that of control, R400 and R2000 groups (P0.05). FeedConversion Ratio (FCR.) and protein efficiency rate (PER) of R800 treatment were significantly lower and higher thanR400 treatment, respectively (P0.05). Condition factor (CF) of control, R200 and R2000 treatments were significantlyhigher than R400 and R800 treatments (P0.05). There were no difference on serum lysozyme, superoxide dismutaseand malondialdehyde (P0.05), and glucose and cortisol level of serum after 30s air stress were no difference (P0.05), either. However, accumulative survival of control group significantly lower than that of groups with various levelof raffinose after being challenged by Aeromonas hydrophila (P0.05). 800mg/kg of raffinose was recommended touse in diet of Japanese sea bass.