How Se and C affect Fish Health

John Emil HalverSchool 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• Fe3+ -->Fe2+• Cu2+ -->Cu1+• Se4+ --> Se2+• 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.

Selenium4 to Selenium2

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 formsCompound Name Reactions

L-Ascorbic acid C1 Heat. O2, oxidized cpds, metals

L-Ascorbyl-2-sulfate C2S Strong acid to C1

L-Ascorgyl-2-phosphate C2MP Acid, base, phosphatases

L-Ascorbyl-2-triphosphate C2-TP Acid, base, phosphatases

L-Ascorbyl-2-glycoside C2G Acid, base

Dehydro Ascorbic Acid DHC Reduced to C1, oxidized easily

L-Ascorbyl-6-phosphate C6P Heat, O2, oxidized cpds

L-Ascorbyl-palmitate CP Heat, 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

QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

Salmon scurvy can be cured by feeding any of Vitamers C

(50 day exposure test)

Hatchery site Groups tested* % Survival

A 6 71

B 9 54

C 6 41

D 6 21

E 6 80

F 8 90**

G 4 68

H 6 58

J 3 94***

K 3 96***

* Each group contained 200 to 300 fish

** Spring water source with hi Se and CU

*** Fed diet H440 with C, Se, and E supplements

(Source: USFWS reports Marrowstone Field Station, 1992

Table 1 Salmon Seawater Survival

Disaster at sea

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

The DiStressed Fish 1

Glutathione Peroxidase Activity (uM/mg protein)

hatchery smolts, Lower Granite Dam13-May 5.15 + .7 14-May 6.11 + .119-May 16.44 + 4 20-May 27.93 + 4

hatchery smolts, Bonneville Dam

GTPX Rises with stress

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

Tissue Selenium Loss in Hatchery Chinook After 30 Hour Barge Transport

01234

1 2Mic

rogr

am/g

ram

Loading Site Discharge Site

1) Lower Granite Dam on Snake River, Washington2) Seaward of Bonneville Dam on Columbia RiverUnited States Army Corps Engineer Study, 2001

Dr. Halver speaking at Pecs, Hungary

Dietary Needs (mg/kg dry diet) No Deficiency Normal Growth

Stress

Se 0.25-0.45 1-2 7-8

C 10-15 200-300 1000

Zn 25-40 50-60 ???

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