| A detailed review of studying status on nutritional physiology of abalone, and advances of studies on metabolism of vitamin BS was undertaken. A series of experiments were conducted to elucidate some mechanisms of vitamin BS on the metabolism of nutrient in abalone, Haliotis discus hannai Ino. The interactions of pyridoxine (PN) and thiamin with nutrient (lipid, carbohydrate and protein) metabolism and the effects of PN on the immune system in abalone were investigated. The current studies include the followings: (1) The effects pyridoxine on the growth, serum cholesterol and triglyceride, fatty acid of total lipids and polar lipids in muscle and hepatopancreas from abalone, H. discus hannai. (2) The effects of thiamine on serum glucose and transketolase, tissue glucogen and hormone (insulin, glucagon, growth hormone and cortisol) in abalone, H. discus hannai. (3) The interaction of dietary pyridoxine and protein on the growth, aminotransferase activity and protein metabolism in abalone, H. discus hannai. (4) The effects of pyridoxine on the growth, the cellular and humoral immune responses in abalone, H. discus hannai. The results are summarized as follows.(1) A feeding experiment was conducted to investigate the effects of dietary pyridoxine (PN) on the lipid metabolism of abalone, Haliotis discus hannai Ino. Four semi-purified diets were formulated to contain 0, 40, 800 mg PN kg"1 or 80mg kg"1 of 4-deoxypyridoxine (4-DPD, PN antagonist). Each diet was fed to three replicate groups of abalone (initial weight 65.83 0.17g; initial shell length 78.04 0.26mm) in a recirculation system for 90 days. The results showed that daily increment in shell length (DISL) in abalone significantly elevated with dietary PN supplementation (P<0.05). Weight gain ratio (WGR) and hepatosomatic index (HSI) in abalone fed the PN-free diet or the one with 4-DPD (P<0.05) were slightly reduced with no significant differences among dietary treatments (P>0.05). The serum cholesterol concentration was significantly increased (P<0.05) in abalone fed the PN-free diet (55.35 mg ml-1) or the one with 4-DPD (57.99 mg ml-1), while the serum triglycerideconcentration in abalone fed 4-DPD, the PN-free diet, or 800 mg PN kg"1 was all significantly decreased (PO.05). Dietary PN significantly influenced the fatty acid pattern in the tissues of abalone. The deficient PN resulted in the increased 18:2n-6 and the reduced 20:4n-6 in total lipids or polar lipids of muscle and hepatopancreas (PO.05). The increased 18:3n-3 and reduced 20:5n-3 and 22:5n-3 were also observed in hepatopancreas lipid of abalone fed the PN-free diet or the one with 4-DPD (PO.05). There were no significant differences in lipid and fatty acid compositions between abalone fed 40 mg PN kg-1 and those fed 800 mg PN kg-1 (P>0.05) except for the serum triglyceride. These results suggest that pyridoxine deficiency in diets resulted in abnormal lipid metabolism, and inhibited the desaturation and elongation of C18 fatty acids in tissues. The dietary level of 40 mg PN kg"]is needed for H. discus hannai, to maintain normal lipid metabolism.(2) A 90-day feeding experiment was conducted in a recirculation water system to investigate the effects of thiamine on the growth and carbohydrate metabolism in abalone, H. discus hannai. Triplicate groups of adult abalone (mean weight 58.76+ O.lOg; mean shell length 74.6 + 0.41mm) were fed to satiation one of three semi-purified diets (TO: 0 mg kg'1, T60: 60 mg kg'1, T1200: 1200 mg kg'1) or the control diet (L. japonicd). The results showed that the thiamine-free diet produced the significantly decreased DISL and HSI (PO.05), but dietary thiamine had no significant effects on WGR and hepatopancreas weight (P>0.05). The activity of transketolase in serum significantly elevated with dietary thiamine supplementation (PO.05). Serum glucose was independent of dietary treatments (P>0.05). However, the hepatopancreas glucogen in abalone fed the thiamine-free diet was significantly higher than those fed other diets (PO.05), and the muscle glucogen, was...
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