BACKGROUND: The immunostimulating effect of Aloe vera in mammals has been documented, but few works were done on effect of A. vera on fish health and immune responses. OBJECTIVES: In this study the effect of oral administration of A. vera on growth indices, hematological parameters and immune responses of rainbow trout were investigated. METHODS: One thousand five hundred rainbow trout fingerling (20 ± 2 g, Mean ± SD) were divided into five groups, each in triplicate, in farm scale. Group 1 were adopted as control and fed with non-supplemented feed, groups 2 to 5 were fed with diet supplemented by 0.05%, 0.1%, 0.2% and 0.5% A. vera extract respectivly for 60 days. Growth indices (SGR, FCR, PWG, FER, PER and CF) calculated in day 30 and 60. Blood samples were taken in day 60 and hematological parameters including: PCV, Hb, RBC, WBC, MCH, MCV, MCHC as well as immunological parameters including: Lysozyme and serum bactericidal activity, serum total protein and globulin were compared among the groups. RESULTS: Results showed that all calculated growth indices (except CF) and all mentioned immunological parameters were significantly increased in fish fed with 0.1% and 0.2% A. vera supplemented food (G3 and G4) compare to control group (P < 0.05). Hematological parameters, HB, RBC, WBC and PCV showed a significant enhancement in G3 and G4 compare to control (P<0.05), but MCV, MCH and MCHC showed no significant changes (P > 0.05). CONCLUSIONS: It can be concluded that oral administration of 0.1% and 0. 2% A. vera crud extract in food (G3 and G4) can improved growth indices, stimulate non-specific immune responces and affect some hematological parameters positively in rainbow trout.

Background: Diabetes is a metabolic disease that is associated with hyperglycemia and infertility. Previous studies indicate that aloe vera may positively affect the blood glucose and fertility. Objective: the present study was carried out to evaluate effect of aloe vera on serum oxidant/antioxidant activity and reproductive hormones following experimental diabetes. Methods: sixty adults male wistar rats were divided to 5 groups. control group(A) was kept without treatment. Group(E) only received aloe vera gel(400 mg/kg-orally). Experimental diabete mellitus was induced in 3 groups of rats by streptozotocin( 65 mg/kg-Ip). One diabetic group was kept without treatment(B). Another diabetic group received aloe vera gel(400 mg/kg-orally)(C) and another received insulin(10 units)(D). Aloe vera gel and insulin was administration for 30 days then, the rats were anesthetized and blood collected. The amount of malondialdehid(MDA), anti oxidant activity(AOA), glutathion peroxidase activity(GPX), thiol protein(TSH), testosterone, LH and FSH was determined in serum. Results: level of testosterone was significantly decreased while amount of MDA, TSH, GPX and AOA was significantly increased in non-treated diabetic rats. Aloe vera increased antioxidant defense. Conclusions: Aloe vera improves antioxidant activity and reduces diabetic complications. Key words: Diabetes, Aloe vera, Anti oxidant, pituitary – sexual hormones, rat.