International Journal of Veterinary Research

fa The effect of feeding with hydroalcoholic extract of Spirulina platensis on the growth and immune responses of Rainbow trout (Oncorhynchus mykiss) fry تخصصي Special پژوهشي Research Rainbow trout (Oncorhynchus mykiss) is the most economically important farmed species in Iran, whose intensive culture is associated with various stresses and makes the fish susceptible to various diseases. Using natural immune stimulants is one of the most effective ways to boost immunity and prevent diseases in fish. Spirulina platensis contains protein, vitamins, minerals, essential amino acids, fatty acids and antioxidant pigments such as beta-carotenoid and is considered as a growth stimulant, probiotic and immune system booster in aquatic animals. The present study was conducted in order to investigate the effect of hydroalcoholic extract of spirulina platensis algae on growth and immune responses of rainbow trout (O. mykiss) fry. A completely randomized experimental design was developed with five test groups including commercial diet as control along with 2, 4, 6 and 8% hydroalcoholic extract of spirulina algae each containing three replicates. two thousand and four hundred rainbow trout with average initial weight of 20±0.5 g were assigned to 20 experimental rectangular polyethylene pools (v= 0.3m3). the adaptation and expriment periods were 15 and 60 days, respectively. Biometry performed once every 20 days. Rainbow trout fed by 8% S. platensis (treatment 5) showed a significant difference in percentage of the condition factor (1.16±0.01), Growth Rate (0.41±0.02), Specific Growth Rate (0.38±0.015), Lysozyme Activity (2.77±0.12 mgL-1) and the survival to oxygen depletion (62.96±1.85), temperature (57.40±4.89) and salinity stresses (74.07±1.85) with the other groups (p<0.05). Adding 8% S. platensis hydroalcoholic extract as a food supplement was found to be improved the growth, and immune responses performance in rainbow trout fry.   Spirulina platensis, rainbow trout, growth index, immune response 55 72 http://injvr.com/browse.php?a_code=A-10-1-14&slc_lang=fa&sid=1 R. Nahavandi 1003194753284600410 1003194753284600410 Yes Animal Science Research Institute of Iran (ASRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. A. Nekuiefard 1003194753284600411 1003194753284600411 No National Artemia Research Center, Iranian Fisheries Science Research Institute, Agricultural Reseach, Education and Extension Organization, Urmia, Iran. M. Seidgar 1003194753284600412 1003194753284600412 No National Artemia Research Center, Iranian Fisheries Science Research Institute, Agricultural Reseach, Education and Extension Organization, Urmia, Iran.