title: Dietary β-glucan improved growth performance, Vibrio counts, haematological parameters and stress resistance of pompano fish, Trachinotus ovatus Linnaeus, 1758.
abstract: 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 (R(2) = 98.53%), 0.120% at day 28 (R(2) = 78.55%), 0.115% at day 42 (R(2) = 62.21%) and 0.090% at day 56 (R(2) = 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% (R(2) = 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.
authors.affiliation: Vietnam Academy of Science and Technology, Institute of Oceanography, 01 Cau Da, Nha Trang, Viet Nam. Electronic address: dohuuhoang2002@yahoo.com.
authors.forename: Hoang
authors.initials: H
authors.lastname: Do Huu
authors.affiliation: Vietnam Academy of Science and Technology, Institute of Oceanography, 01 Cau Da, Nha Trang, Viet Nam.
authors.forename: Huynh Minh
authors.initials: HM
authors.lastname: Sang
authors.affiliation: Vietnam Academy of Science and Technology, Institute of Oceanography, 01 Cau Da, Nha Trang, Viet Nam.
authors.forename: Nguyen Thi
authors.initials: NT
authors.lastname: Thanh Thuy
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004032:Diet / Q000662:veterinary*; D005393:Fish Diseases / Q000382:microbiology / Q000517:prevention & control; D007113:Immunity, Innate; D007422:Intestines / Q000382:microbiology; D010473:Perciformes / Q000097:blood / Q000254:growth & development / Q000502:physiology*; D056692:Prebiotics; D011897:Random Allocation; D054712:Salinity; D013312:Stress, Physiological / Q000502:physiology*; D014733:Vibrio / Q000502:physiology; D014735:Vibrio Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D056692:Prebiotics; D047071:beta-Glucans
keywords: Diet requirement; Growth; Haematology; Intestinal Vibrio count; Pompano fish; Stress resistance; Survival; Trachinotus ovatus; β-Glucan