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The objective of this experiment was to assess the influence of some phytobiotics on growth performance of stellate sturgeon (A. stellatus). There were two experimental variants: V1–thyme and V2–seabuckthorn. The fish used in this experiment were one year and four months old, with an initial mean weight of 122.78±31.60 g/fish (V1), respectively 121.21±32.54 g/fish (V2). The phytobiotics used, thyme (Thymus vulgaris) and seabuckthorn (Hippophae rhamnoides), have been embedded in fodder, by using gelatin, having a concentration of 2%/ kg fodder. Alterna Storioni feed-48% crude protein was used. The water quality parameters during the experiment were within normal limits for an optimum growth of experimental fish. At the end of the experiment significant differences (p0.05). Highest individual growth rate value (105.90 g) was recorded in V2 case and the lowest value (98.45 g) in case of V1. As a conclusion, it can be said that the two types of phytobiotics (thyme, seabuckthorn), administered in a concentration of 2%/kg fodder, have influenced the growth performance of stellate sturgeons.

Addition of natural additives (prebiotics, probiotics, phytobiotics) in fish feed is a benefic method because it leads to improved growth performance of fish reared in intensive production systems. Sea buckthorn is one of the most commonly phytobiotics used in aquaculture because of its antioxidant, antimicrobial, immunostimulant, anti-stress, cytoprotective, liver and tissue regeneration properties. Sea buckthorn berries are rich in vitamins (B, C, E and K), flavonoids, carotenoids, tocopherols and many volatile compounds. In this context the aim of this study was to evaluate the effects of dietary vitamin E (500 mg/kg diet) and sea buckthorn on growth performance and survival of the A. stellatus juveniles reared in a recirculating aquaculture system. The experiment took place in the recirculating pilot system of “Dunărea de Jos” University of Galaţi. In order to emphasize the influence of the above mentioned immunostimulants on sevruga fingerlings with different genetic background, four experimental groups from different genitors (V1: ♀2 Danube x ♂1 Aquaculture, V2: ♀1 Danube x ♂1 Danube, V3: ♀1 Danube x ♂2 Aquaculture and V4: ♀2 Danube x ♂2 Danube) have been used. At the end of the experiment no significant differences (p>0.05) were observed in terms of final mean weight, individual growth rate, SGR, FCR, PER, between the sevruga fingerlings obtained from wild genitors, comparing with those obtained from aquaculture genitors.