The effect of microbial protein on the physiological state and tissue distribution of macro- and microelements in Nile Tilapia (Oreochromis niloticus)

In the context of the dynamic development of aquaculture, optimizing diets and maintaining fish health are of paramount importance. This work is devoted to the study of the effect of the protein-mineral feed additive DREAMFID® on the physiological status of fingerlings of the Nile tilapia (Oreochromis niloticus) and the dynamics of accumulation and resorption of key trace elements in their tissues and organs. The experimental mixed feed with DREAMFID® was characterized by an increased protein content (64.3 %) and a reduced fat level (8.9 %) compared with the control sample. Trace element analysis revealed a significant increase in the concentrations of copper (299 mg/kg) and potassium (7290 mg/kg) in the experimental group, while in the control feed the values were 11.3 mg/kg and 4480 mg/kg, respectively. In fish treated with DREAMFID®, stable blood glucose levels were observed, ranging from 4–5.7 mmol/l, which corresponds to the optimal range (5.0–6.0 mmol/l). Analysis of the leukogram revealed an increase in rod-shaped neutrophils (12.9 %) and monocytes (8 %) in control individuals, which may indicate the development of inflammatory processes. In the group receiving DREAMFID®, these indicators were within the normal range. The study of the dynamics of macro- and microelements in tissues and organs demonstrated general trends, however, specific differences due to different composition of diets were also recorded. The results of the study confirm the effectiveness of using the feed additive DREAMFID® to improve the physiological state of the Nile tilapia and increase its productive characteristics.