Study effect of Macrogard on efficacy of Anti-streptococcus iniae vaccine and some haematological and growth parameters in rainbow trout (Oncorhynchus mykiss)

The purpose of this study was to evaluate the effect of orally administered β-glucan (Macrogard) (1 g/kg food/day for 45 days) and Streptococcus vaccines on growth and hematological parameters (including hematocrit، hemoglobin، MCV، MCH، MCHC and total red and white blood cells) of rainbow trout. Treatments of control، vaccine، vaccines to Macrogard and Macrogard were examined in a 45 days period. Vaccination was performed once using the immersion. The results showed that the fish growth and FCR in Macrogard treatment significant effect compared to control (p<0. 05). Significant increase observed with total numbers of white blood cells in vaccine treatment and Macrogard plus vaccine compared to control. (p<0. 05). The white cell differential and lymphocyte counts showed significant difference in Macrogard، vaccine and vaccine plus Macrogard treatments in comparison with control (p<0. 05). The result of survival of fish challenged with Streptococcus iniae via bath route was 46. 75%، while those for vaccine treatment، Macrogard plus vaccine and Macrogard were 68. 18، 83. 95 and 50. 91%، respectively. The results of this study showed that supplement of Macrogard has positive effect on growth and viability of rainbow trout and can enhance efficacy of anti- streptococcus iniae vaccine.