Ảnh hưởng của vi khuẩn <i>Lactobacillus fermentum</i> đến một số chỉ tiêu miễn dịch và khả năng kháng bệnh của cá chẽm (<i>Lates calcarifer</i>)

Abstract

    The aim of this study is to evaluate - effects of Lactobacillus fermentum supplement in diets on the innate immune response of barramundi (Lates calcarifer). The experiment was designed in 4 treatments with triplicates. The negative control (NT 1): no L. fermentum supplement to the barramundi diet and no S. iniae i.p injection. The positive control (NT 2): no L. fermentum supplement to the barramundi diet and S. iniae i.p injection to the barramundi cavity after 14 days with the dose of 1.9x10⁵ CFU/mL/fish. The treatment 3 (NT 3): L. fermentum supplement to the barramundi diet at 10⁹ CFU/g in feed and no S. iniae i.p injection. The treatment 4 (NT 4): L. fermentum supplement to the barramundi diet at 10⁹ CFU/g in feed for 14 days before

i.p injection to the barramundi with the dose of 1.9x10⁵ CFU S. iniae /mL/fish. Blood samples were colleted on day 1, 14, 21 and 28 for hamatological analysis and the ability of fish serum collected to identify the against of S. iniae. The results showed that the number of red blood cells and total white blood cells of fish in NT 3 and NT 4 on day 14, 21 and 28 were significantly higher than those from NT 1 and NT 2 (p<0.05). Total white blood cells of fish and the antagonistic ability of barramundi serum to S. iniae from NT 4 was significantly higher than those from NT 2 (p<0.05) on day 21. The lysozyme activity of fish in NT 4 was not significantly higher than those in NT 2 treatment (p>0.05) on day 21. On day 28, the survival rate of fish in NT 2 and NT 4 treatments were 23.7% and 52.3%, respectively.

Keywords: Barramundi, immune response, Lactobacillus fermentum.