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Citrus peel is a natural source of antioxidants and the use of its natural extracts to improve the quality of fish is increasing. The effect of orange peel extract on the chemical and sensory properties of Huso huso fillet when refrigerated (4±1 °C) was investigated. In this study, fish fillets with aqueous solutions of ethanolic extract of orange peel (w / w 5%) or (5 ml of extract in 100 ml of solvent), orange peel extract (w / w 6%) and orange peel extract (w / w 7%) were tested as natural preservatives for 30 minutes. Control samples were immersed in distilled water for 30 minutes. Control and treated samples were packed with ethanolic extract of orange peel and stored for 15 days. Samples are then taken at regular intervals for chemical properties of pH, free fatty acid (FFA), peroxide (PV), thiobarbituric acid (TBA), total volatile nitrogen bases (TVB-N) and sensory evaluation (texture, color, odor and acceptance) were studied. Analysis of the results of chemical tests and sensory evaluation showed that orange peel extract maintains good quality characteristics and increases the shelf life of fish samples during storage at refrigerator temperature. 7% orange peel extract and then 6% and 5% orange peel extract significantly (P <0.01) delayed the oxidation and hydrolysis of fat in the samples that treated with the Orange peel extract.

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In this study, the effectiveness of 4 killed VNN vaccines along with three types of adjuvants was evaluated by both immersion and injection methods. About 540 fish weighing 7-10 g of ozone (Acipenser stellatus Pallas 1771) were considered. Vaccination was performed in two stages one month apart, and one month after the second recurrence, exposure to the acute live virus was performed. During this period, the mortality rate of immersion and injection groups was 12.9% and 19.8%, respectively, compared to 100% mortality in the control group. Blood sampling was performed to assess immune factors (superoxide dismutase, lysozyme) in four stages before the first vaccination in the adaptation period, after the first vaccination, after the second vaccination one month and after exposure to live virus Acute was performed to identify changes before and after exposure to the virus. The results of the present study showed that immunization vaccination in the vaccinated group with the vaccine containing IMS 1312 SEPPIC adjuvant significantly higher levels of superoxide dismutase 1745 IU / MI (p<0.05) and lysozyme 40.6 (p<0.05). Compared to other groups, which proves its better efficacy compared to other vaccines. Therefore, a vaccine killed with 75% IMS 1312 SEPPIC adjuvant can be recommended for vaccination against VNN.