Effects of Dietary Supplementation at Nile tilapia with Thymus vulgaris, Trigonela foenum graecum and Azadirachta indica on Welfare Status

Abstract

At fish, the evaluation of hematological profile is an important step in monitoring the welfare status. The aim of this research was to determine the influence of dietary supplementation with some phytobiotics on hematological profile, some biochemical indices of blood and on the immune response at Oreochromis niloticus reared in a recirculating aquaculture system. The experimental variants were organized as follows: V1-control, V2-1% thyme, V3-1% fenugreek and V4-1% neem. Blood analysis, glucose and total protein were carried out by methods commonly used in fish hematology. Lysozyme activity was measured by a turbiometric assay and cortisol was determined by an immunoenzymatic assay. At the end of the experiment was observed that the phytobiotics administration has led to significant changes (p˂0.05) in case of erythrocytes number (p=0.002) and relative number of monocytes (%) (p=0.045). Comparing final results with the value obtained at the beginning of the experiment were noted significant differences (p˂0.05) in case of erythrocytes number (p=0.037), PVC (p=0.001), MCHC (p=0.000), glucose (p=0.035), monocytes (%) (p=0.042). The best value were registered in V2 and V3 variant. The concentration of cortisol was lower in variants in which the dietary were supplemented with phytobiotics compared to the control variant. The neem (V4) administration led to intensifying the lysozyme activity than other experimental variants. In conclusion, we demonstrated that the dietary supplementation especially with thyme and fenugreek, but also with neem has improved the physiological status at Oreochromis niloticus species.