Fish, carotenoid and CR

[Guest guest]

Hi All

For background, " Astaxanthin, a naturally occurring carotenoid pigment, is a

powerful biological antioxidant. Astaxanthin exhibits strong free radical

scavenging

activity and protects against lipid peroxidation and oxidative damage of

LDL-cholesterol, cell membranes, cells, and tissues. "

The carotenoid metabolite, idoxanthin, is found in alga that fatty fish consume

and

may consequently have in their tissues.

Would this be a model for factors affecting carotenoid use in our food and

selves?

Aas, G.H., Bjerkeng, B., Hatlen, B. & Storebakken, T. (1997) Idoxanthin, a major

carotenoid in the flesh of Arctic charr (Salvelinus alpinus) fed diets

containing

astaxanthin. Aquaculture 150:135-142.

Now, a paper that is not pdf-available seems to examine how CR and temperature

affect astaxanthin uptake into blood and conversion into the metabolite,

idoxanthin.

See:

Ytrestoyl T, Struksnaes G, Koppe W, Bjerkeng B.

Effects of temperature and feed intake on astaxanthin digestibility and

metabolism

in Atlantic salmon, Salmo salar.

Comp Biochem Physiol B Biochem Mol Biol. 2005 Oct 18; [Epub ahead of print]

PMID: 16242366

The effects of feed intake, growth rate and temperature (8 and 12 degrees C) on

apparent digestibility coefficients (ADC), blood uptake of individual

astaxanthin

E/Z isomers and metabolism of astaxanthin

(3,3'-dihydroxy-beta,beta-carotene-4,4'-dione) were determined in Atlantic

salmon.

Accumulation of idoxanthin (3,4,3'-trihydroxy-beta,beta-carotene-4-one) in

plasma

was used to indicate metabolic transformation of astaxanthin. Quadruplicate

groups

of fish were subjected to three different treatments; one treatment was kept at

12

degrees C and fed to satiation. Another treatment kept at 12 degrees C was

pair-fed

with fish fed to satiation at 8 degrees C, resulting in a restricted feeding

regime

for the former treatment. After 2 months of feeding, the fish were fed a single

meal

containing ballotini glass beads to determine individual feed intake and

Y(2)O(3) as

an inert marker to determine ADCs. The faeces samples were pooled into 6

categories

according to individual meal size (range 0.2-1.5% of body weight) and the ADCs

for

different meal sizes were determined. ADCs of astaxanthin ranged from 20% to 60%

but

were not significantly correlated with meal size. However, fish kept at 12

degrees C

had approximately 10% higher ADC than fish kept at 8 degrees C (p=0.032). Growth

rate and plasma astaxanthin concentration were higher at higher temperature and

higher ration. Plasma concentration of idoxanthin was not affected by

temperature or

by meal size. The incidence of fin erosion and non-feeding individuals was

significantly higher among fish fed a restricted ration indicating more

aggressive

interactions. Fish with visible fin damage had a tendency for having higher

idoxanthin content in plasma than fish without noticeable fin damage. It is

concluded that temperature but not individual meal size affect ADC of

astaxanthin,

whereas both influence plasma astaxanthin levels and may therefore affect the

efficiency of astaxanthin utilization.

Al Pater, PhD; email: old542000@...

__________________________________

- PC Magazine Editors' Choice 2005

http://mail.