How Se and C affect Fish Health John Emil Halver School of Aquatic & Fishery Sciences University of Washington; Seattle, WA.

C FUNCTIONS IN FISH HEALTH Hydroxylation of procollagen Hydroxylation of tryptophan Intracellular reducing agent Hydroxylation of steriods Erythrocyte maturation Rapid wound repair Serum iron binding Resistance to Vibrio Mixed function oxidases Enhanced phagocytic index Resistance to Edwardsiella Enhanced antibody production A-C-E-Se axis

Ascorbate roles in metabolism PROLINE --> HYDROXYPROLINE TRYPTOPHAN --> SERATONIN TYROSINE --> NOREPINEPHRINE OSTEOBLASTS --> WOUND REPAIR VASO-HUMORAL --> BLOOD FLOW TOXICANTS -->MIXED Fn OXIDASES STEROIDS -->STEROLS Fe >Fe 2 + Cu >Cu 1 + Se > Se 2 + CHOLESTEROL -> BILE ACIDS

Proline to Hydroxyproline The amino acid proline is hydroxylated through the reducing action of ascorbic acid in the presence of ferrric ion to form hydroxyproline, which is polymerized to form the fiberous structure of tissue membranes.

Tryptophan to Seratonin Ascorbic acid provides the reducing agent to convert tryptophan to the hormone seratonin.

Tyrosine to Norepinephrine Ascorbic acid also provides the reducing factor to convert tyrosine to the hormone norepinephrine.

Osteoblasts in Wound repair Osteoblasts are the first cells formed in tissue wound repair, and cellular restructure. Ascorbic acid is involved in the synthesis of hydroxyproline amino acid that is a major component of the cellular membrane.

Vaso-humoral structure and Blood flow The elastic characteristics of the vascular system are determined by the hydroxyproline constituants, which are dependent upon ascorbate reserves during formation of the fiberous tissues.

Toxicants and Mixed Function Oxidases The first tissue reaction to toxicants is hydroxylation of the chemical compounds involved. The mixed function oxidases require ascorbate in the oxidation-reduction process involved.

Steroids and Sterols The conversion of steroids to sterols involves ascorbic acid in the hydroxylation in the oxidation reduction process involved.

Ferric to Ferrous ions Ascorbic acid is a reducing agent for the conversion of ferric to ferrous ions.

Cuppric to cupprus ions Ascorbic acid acts as a reducing agent to change copper state in compounds involved in intermediary metabolism.

Selenium 4 to Selenium 2 Ascorbic acid acts as the major intracellular reducing agent to reduce selenium to an active state for glutathione peroxidase reduction of lipid peroxides to alcohols.

Cholesterol to Bile acids The conversion of cholesterol to bile acids occurs with ascorbate involved in the oxidation-reduction processes.

Stability of C forms CompoundNameReactions L-Ascorbic acidC1Heat. O2, oxidized cpds, metals L-Ascorbyl-2-sulfateC2SStrong acid to C1 L-Ascorgyl-2-phosphateC2MPAcid, base, phosphatases L-Ascorbyl-2-triphosphateC2-TPAcid, base, phosphatases L-Ascorbyl-2-glycosideC2GAcid, base Dehydro Ascorbic AcidDHCReduced to C1, oxidized easily L-Ascorbyl-6-phosphateC6PHeat, O2, oxidized cpds L-Ascorbyl-palmitateCPHeat, O2, oxidized cpds Food stability: C2S> C2TP> C2MP> C2G> C6P> CP> DHC> C1 The stability of various forms of ascorbate vary. Many of these compounds require enzymatic conversion to the active ascorbic acid or C1 reduced condition.

3 Cs and a stranger HPLC analysis of tissues indicate 3 recognized ascorbate derivatives, and a peak lying between ascorbate-2-sulphate and ascorbate-2- monophosphate.

C reduces Vibrio mortality 1 gram of C/kg feed dramatically reduces mortality from Vibrio disease in trout.

Many Cs can cure scurvy Salmon scurvy can be cured by feeding any of Vitamers C

Disaster at sea Salmon smolts on low Se and C diets die when converted to sea water environment.

The DiStressed Fish 1

GTPX Rises with stress Salmon smolts confined and barged 30 hrs showed stress and GTPX synthesis.

Dr. Halver speaking at Pecs, Hungary

Dietary Needs (mg/kg dry diet) No DeficiencyNormal Growth Stress Se C Zn ??? Stress increases the dietary needs for Se & C in GTPX, and probably also for Cu & Zn that are involved in SOD structures.

Dr. John Emil Halver