title: Effects of dietary pyridoxine on immune responses in abalone, Haliotis discus hannai Ino.
abstract: A feeding experiment was conducted to investigate the effects of dietary pyridoxine (PN) on the immune responses of abalone, Haliotis discus hannai Ino. Purified diets supplemented with 0, 40, 800 mg PN kg(-1) or 80 mg kg(-1) of 4-deoxypyridoxine (PN antagonist) were fed to adult abalone (initial weight 45.77 +/- 0.25 g; initial shell length 68.02 +/- 0.78 mm) for 90 days. The air-dried brown kelp, Laminaria japonica, was used as a control diet. Each diet was fed to three replicate groups of abalone in a recirculation system using a completely randomised design. The results showed that weight gain ratio (WGR) of the abalone generally increased with the level of dietary PN supplementation though no significant differences were found among the treatments (P > 0.05). Phagocytic and phenoloxidase activities were significantly higher in abalone fed diets supplemented with 800 mg PN kg(-1) than those fed the PN-free diet or the one with 4-deoxypyridoxine (P < 0.05). Agglutination titre and respiratory burst activity were significantly higher in abalone fed diets supplemented with 40 mg PN kg(-1) than those fed the PN-free diet or the one with 4-deoxypyridoxine (P < 0.05). There were no significant differences in immunological characteristics between the abalone fed the diet containing 40 mg PN kg(-1) and those fed the diet containing 800 mg PN kg(-1) (P > 0.05). L. japonica resulted in significantly lower agglutination titre, respiratory burst and phagocytic activities than the artificial diets supplemented with 40 or 800 mg PN kg(-1) (P < 0.05). Total haemocyte count (THC), serum protein concentration, and the activities of lysozyme and acid phosphatase were not significantly affected by the dietary treatments (P > 0.05). These results demonstrate that dietary deficiency of pyridoxine suppresses the immune functions in H. discus hannai, and further investigations are needed to optimise the dietary level of this vitamin for maintaining the best immune responses in abalone.
authors.affiliation: The Key Laboratory of Mariculture (Education Ministry of China), Ocean University of China, Qingdao.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Kangsen
authors.initials: K
authors.lastname: Mai
authors.forename: Wenbing
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Liufu
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Beiping
authors.initials: B
authors.lastname: Tan
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000371:Agglutination; D000704:Analysis of Variance; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D001772:Blood Cell Count; D001798:Blood Proteins; D001835:Body Weight; D002681:China; D004032:Diet; D004305:Dose-Response Relationship, Drug; D007111:Immunity, Cellular / Q000187:drug effects*; D008974:Mollusca / Q000276:immunology*; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects; D011736:Pyridoxine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016897:Respiratory Burst / Q000187:drug effects
chemical_list: D001798:Blood Proteins; C004675:4-deoxypyridoxine; D014442:Monophenol Monooxygenase; D000135:Acid Phosphatase; D011736:Pyridoxine