Mohammad Hossien khanjani

This study aimed to investigate the effect of β-glucan in rainbow trout's diet on survival, growth performance, haematological, immunity and biochemical parameters. Rainbow trout (Oncorhynchus mykiss) with an average weight of 6.33 ± 0.09 were stocked in 30 fibreglass tanks with a volume of 200 L. Four treatments including control group (0%), 0.05%, 0.1% and 0.2% of β-glucan were considered for 8 weeks. The results showed that the survival and growth performance of rainbow trout in the control group were at the lowest level and showed a significant difference (p < 0.05) with other treatments. The highest percentage of haematocrit (47.9%), white blood cell count and neutrophil percentage (35.2%) was observed in the treatment with 0.2% β-glucan. Also, the highest lysosomal activity (59.7 units’ ml−1), IgM (54.7 mg dl−1), C3 and C4 was obtained in 0.2% β-glucan treatment. Biochemical parameters indicated improvement in treatments fed with 0.1 and 0.2% β-glucan. In conclusion, the present study suggested that 0.2% β-glucan in the diet of rainbow trout improves growth performance, survival, haematological, immunity and biochemical parameters.