Enhanced survival and immunity in β-glucan or sodium alginate or thyroxin stimulated fry of bluefin bream, Sparidentax hasta

• Published in: Animal feed science and technology 2022-08, Vol.290, p.115344, Article 115344
• Main Authors: Azad, I.S., Al-Gharabally, H., El-Dakour, S.
• Format: Article
• Language: English
• Subjects: Challenge; Fry; Immunostimulant; Larvae; Survival; Vaccine
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2022.115344

Bluefin bream (Sparidentax hasta) fry were immunostimulated using β-glucan (BG) or sodium alginate (SA) or thyroxine sodium (Eltroxin™, T4) at 45 mg, 3 g and 0.01 mg per litre, respectively. The fry were stocked @ 15 fry per litre in each one-ton tank under a triplicated random design. The tanks were supplied with filtered aerated seawater. The best enhancement in growth and survival (12.91 ± 3.48%) of fry until 14 dps was with T4 treatment while, BG was better than T4 at 21 dps. Immune parameters suggest a superior performance of the immunostimulated fry in their phagocyte response, lysozyme activity, hemagglutinin, and bacterial agglutinin levels. Expression of IgM, IL-1β and Mx genes were upregulated with T4 and BG treatments at all the three samplings. All the treatments were subjected to a bath challenge test using live Proteus vulgaris (107 colony forming unit (CFU ml−1)). Survival response was the best in fry stimulated with SA and T4 (92% and 88% respectively) followed by BG-stimulated fry (75%). Vaccine efficacy was also improved in immunostimulated fry (60 dph) when treated with BG and T4 with a memory factor (MF) of 1.87 and 1.25, respectively. [Display omitted] •The best enhancement in growth and survival of bluefin bream larvae until 14 dps was with T4 (0.01 mg/l) treatment.•BG (45 mg/l) better than T4 at 21 dps. IgM, IL-1β and Mx genes were upregulated with T4 and BG.•Best survival of challenged fish was with SA and T4.