The effects of dietary lysozyme on growth performance and haematological indices of rainbow trout (Oncorhynchus mykiss) fingerling

The present study investigates the effects of dietary lysozyme on growth performance and haematological indices of rainbow trout (Oncorhynchus mykiss) fingerlings. One hundred and twenty Juvenile rainbow trout fish (initial average weight 5.46±0.05 g) were fed on varying levels of dietary lysozyme (0, 0.5, 1 and 1.5 g kg-1) for 8 weeks. Thereafter, growth performance as well as haematological indices including WBC, RBC and Hct were measured. Evaluation of growth performance showed no significant increase in fishes fed on different levels of dietary lysozyme (P>0.05). Also, feeding on dietary lysozyme significantly increased WBC compared control (P<0.05); the highest level was detected in 1.5 g kg-1 treatment. Furthermore, RBC of fish fed 1 or 1.5 g kg-1 lysozyme were significantly higher than other treatments. The same results were noticed in case of Hct which was higher in fish fed treated diet. These results indicated that dietary lysozyme affect haematological parameters rather than growth performance