Effects of red beet (Beta vulgaris Var. cruenta) meal in diets on growth performance, body composition and digestive enzyme activity of rainbow trout (Oncorhynchus mykiss)

In this thesis study, the effects of dietary inclusion of red beet meal at high or low fish meal diets on rainbow trout growth performance, colouring, enzyme activities in immune and digestive system have been investigated. With this aim, four different feed (High Fish Meal-HFM, Low Fish Meal-LFM, High Fish Meal and 8% red beet meal-HFM-R, Low Fish Meal and 8% red beet meal-LFM-R) were formulated and fish were fed the diet during 45 days. At the end of the study, the final mean weights (FMW) and specific growth rate (SGR) of fish fed with HFM diet were higher than those of all groups (P<0.05). FMW and SGR values of fish fed with LFM and LFM-R diets were similar (P>0.05), and these groups grew better than LFM-R group. The LFM group had the highest fee conversion ratio (FCR) value and was found to be higher than the LFM-R group and lower than the HFM-R group. The protein efficiency ratio (PER) of the LFM and LFM-R groups was found to be significantly lower than the other groups (P<0.05). The respiratory burst was not affected in any experimental groups (P>0.05). Myeloperoxidase was significantly increased in group HFM, HFM-R, LFM-R and LFM respectively (P<0.05). Lysozyme was significantly elevated in group HFM and LFM-R respectively. No differences observed in groups LFM and HFM-R. Pepsin activity was highest in HFM and HFM-B compared to LFM and LFM-R (P<0.05). Trypsin was only increased in LFM compared to other experimental groups (P<0.05). Amylase was determined highest in HFM and LFM groups compared to others. This results suggest that HFM has better result compared to others and red beet meal addition to the fish diet has no positive effects in terms of growth performance and body composition.