effects of different levels of aloe vera l.extract on growth performance, hemato-immunological indices of cyprinus carpio l.

this study was conducted to determine the effects of administration of different concentration of aloe vera crud extract (ace) as a food supplement on growth performance, immune response and disease resistance against aeromonas hydrophila (chester) infection in cyprinus carpio. 360 juvenile c.carpio were randomly divided into four equal groups in triplicates. groups 1 to 4 were fed by basal food supplemented with zero, 0.1, 0.5 and 1% ace respectively, for 60 days. at the end of the experimental period growth performance indices including: specificgrowth rate (sgr), food conversion rate (fcr), food efficacy rate (fer) and percentage weight-gain (pwg) were evaluated. blood samples were taken from each treatment and haematological parameters including: red blood cells (rbc) & white blood cell(wbc) count, differential count, hemoglobin (hb), hematocrit (hct), mean corpuscular volume (mcv), mean corpuscular hemoglobin (mch) and the mean corpuscular hemoglobin concentration (mchc) as well as immunological parameters including: lysozyme activity, serum bactericidal activity, alternative complement activity, respiratory burst activity, serum total protein and globulin were evaluated. finally challenge with aeromonas hydrophila was performed and commutative mortality was calculated. results showed significant improve in growth indices of groups 3 and 4 (p<0.05). pcv and mcv, as well as most of the immune parameters including, lysozyme activity, complement activity, respiratory burst activity and serum bactericidal activity were significantly (p<0.05) higher in groups 3 and 4. in addition the rate of challenge mortality was significantly lower in the 0.5 and 1% ace treated fishes than other groups (p<0.05). in conclusion supplementation of food with 0.5 and 1% ace has immunostimulating, growth stimulation effects, as well as resistance against bacterial infection in c.carpio.