THE INFLUENCE OF SOME PHYTOBIOTICS ON GROWTH PERFORMANCE AT OREOCHROMIS NILOTICUS REARED IN AN INTENSIVE RECIRCULATING AQUACULTURE SYSTEM

The aim of this research is to evaluate the influence of several phytobiotics on growth performance indicators at Oreochromis niloticus species, reared in an intensive recirculating aquaculture system. During six weeks of experiment, a total number of 180 fish, with an initial average biomass of 125.41 ± 34.33g, were divided randomized in four rearing units. The experimental variants were: V1-control, V2-1% thyme (Thymus vulgaris) / kg feed, V3-1% fenugreek (Trigonela foenum graecum) / kg feed, V4-1% neem (Azadirachta indica) / kg feed. Fish were fed with SOPROFISH pelleted feed, with 38% crude protein. Fish were fed four times per day with a daily ration of 3.4% of fish body weight. During the experiment, the physico-chemical parameters of technological water were situated in normal range for optimal growth. Technological parameters analysed had revealed the following aspects at the end of the experiment: the best value of SGR was recorded in V2 – 1.81 %/day and the lowest was encountered in V1 and V4 case – 1.65 %/day; regarding FCR, the best value was found at V2 - 1.26 g feed/g biomass gain and the lowest was recorded at V1 and V4 – 1.44 g feed/g biomass gain. In conclusion,the research shows that the thyme, in 1% concentration per kg diet, has the best effect on growth performance of Oreochromis niloticus.