Dietary β-glucan improved growth performance, Vibrio counts, haematological parameters and stress resistance of pompano fish, Trachinotus ovatus Linnaeus, 1758

• Published in: Fish & shellfish immunology 2016-07, Vol.54, p.402-410
• Main Authors: Do Huu, Hoang, Sang, Huynh Minh, Thanh Thuy, Nguyen Thi
• Format: Article
• Language: English
• Subjects: Animal Feed - analysis; Animals; beta-Glucans - metabolism; Diet - veterinary; Diet requirement; Fish Diseases - microbiology; Fish Diseases - prevention & control; Growth; Haematology; Immunity, Innate; Intestinal Vibrio count; Intestines - microbiology; Marine; Ovatus; Perciformes - blood; Perciformes - growth & development; Perciformes - physiology; Pompano fish; Prebiotics; Random Allocation; Salinity; Stress resistance; Stress, Physiological - physiology; Survival; Trachinotus ovatus; Vibrio; Vibrio - physiology; Vibrio Infections - microbiology; Vibrio Infections - prevention & control; Vibrio Infections - veterinary; β-Glucan
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2016.03.161

This study evaluated effects of graded levels of dietary β-glucan (0, 0.5, 1, 2 and 4 g kg−1) on growth performance, haematological parameters, intestinal Vibrio counts, dose requirement and salinity stress resistance in pompano fish Trachinotus ovatus (6.45 g ± 0.06 (SEM)). After 8-weeks of diet feeding, growth was significantly higher in fish fed diets with 0.10% β-glucan compared to fish fed control diet (no β-glucan). Survival increased significantly in fish fed 0.05 and 0.10% β-glucan compared to control diet. There were significant increases in red blood cells (in 0.20% β-glucan diet), in total leukocytes (in 0.05–0.20% β-glucan diet), in both lymphocyte and monocyte count in fish fed 0.10%–0.40% β-glucan diet. However, dietary β-glucan did not affect neutrophil, eosinophil and basophil counts. Intestinal Vibrio counts were reduced in fish fed any level of β-glucan compared to control. In addition, dietary β-glucan levels highly correlated with growth, survival, intestinal Vibrio counts and haematological index. Optimal β-glucan levels for maximal growth of fish were predicted to be 0.122% at day 21 (R2 = 98.53%), 0.120% at day 28 (R2 = 78.55%), 0.115% at day 42 (R2 = 62.21%) and 0.090% at day 56 (R2 = 75.18%), showing a decreasing β-glucan requirement with increasing fish size. Furthermore, optimal β-glucan levels for maximal haematological parameters based on lymphocyte count, was estimated to be 0.120% (R2 = 98.53%) at day 56. Also, fish fed 0.05%–0.20% β-glucan showed better resistance against salinity stress. In conclusion, β-glucan supplementation is effective for improving growth, intestinal Vibrio counts and boosted stress resistance of the pompano fish, T. ovatus. •Dietary b-glucan improved growth, survival, reduced Vibrio and boosted stress tolerance of pompano fish, Trachinotus ovatus.•Growth was higher in fish fed 0.10% β-glucan.•Stress resistance was higher in fish fed 0.05 – 0.20% β-glucan.•Supplementation of 0.05 – 0.10% β-glucan is recommended.