Role of carotenes in C.p belly redness

[TJ]

I recall some discussion before about how wild-caught newts have redder or more brightly colored bellies than captive-bred ones, and the role of carotenes in this.

In that connection, I just came across this abstract:

An Ultrastructural and Carotenoid Analysis of the Red Ventrum of the Japanese Newt, Cynops pyrrhogaster
(Kumi Matsui, Junsuke Marunouchi & Masahisa Nakamura)

"The ventral skin of the wild Japanese newt Cynops pyrrhogaster is creamy at metamorphosis, but turns red when mature. The color of the ventral skin of laboratory (lab)-reared newts stays yellow throughout their life. However, the mechanism for the red coloration of this animal still remains unknown. In this study, we have performed ultrastructural and carotenoid analyses of the red ventrum of wild and lab-reared Japanese newts. Using electron microscopy, we observed a number of xanthophores having ring carotenoid vesicles (rcv) and homogenous carotenoid granules (hcg) in the ventral red skin of the wild newt. In the skin, beta-carotene and five other kinds of carotenoids were detected by thin-layer chromatography (TLC). In the ventral yellow skin of lab-reared newts, however, only beta-carotene and three other kinds of carotenoids were found. The total amount of carotenoids in the red skin of the wild adult newt was six times more than that of the yellow skin of the lab-reared newt. Moreover, rcv were more abundant in xanthophores in red skin, but hcg were more abundant in yellow skin. These results, taken together, suggest that the presence of carotenoids in rcv in xanthophores is one of the critical factors for producing the red ventral coloration of the Japanese newt C. pyrrhogaster.

Source: Pigment Cell Research (Volume 15, Issue 4, Page 265,- August 2002)

http://www.blackwell-synergy.com/openurl?genre=article&sid=nlmubmed&issn=0893-5785&date=2002&volume=15&issue=4&spage=265

Anybody with access to the full text of this, please don't hesitate to e-mail it to me

 

[TJ]

carotene = any of several orange or red crystalline hydrocarbon pigments C40H56 that occur in the chromoplasts of plants and in the fatty tissues of plant-eating animals and are convertible to vitamin A

(Merriam-Webster Dictionary)

 

[TJ]

An example of a WC C.p of mine that has evidently feasted on carotene-rich foods can be seen at:

http://www.caudata.org/forum/messages/13/6859.jpg

 

[tara]

Tim
very interesting
I am wondering if the colour can change later in life if the diet changes. I will have to find this article.
Tara

 

[nate]

Very cool Tim, thanks for digging that up. I wonder what they were feeding their animals in the lab, because I'v never had the "yellowing" problem with orientalis or pyrrhogaster.

There are certainly "color foods" available for reptiles and tropical fish. I'm sure they could be easily supplemented into the diet of newts, if one is concerned about their colors. I think I'll try it with my cyanurus, just to see.

Tara, I'd bet their belly colors can change later in life, much like captive flamingos can become pink again if fed carotene.

 

[TJ]

Well, it just so happens that there's a followup report that I found later in the day today:

ZOOLOGICAL SCIENCE
Vol. 20 (2003) , No. 7 pp.855-859

Food Habit of the Juvenile of the Japanese Newt Cynops pyrrhogaster (Kumi Matsui, Koji Mochida and Masahisa Nakamura)

ABSTRACT:

"The previous study showed that the red coloration of the ventral skin of the Japanese newt Cynops pyrrhogaster was associated with the number of carotenoid vesicles and the content of carotenoid in the pigment cell of the skin. To elucidate the mechanism for the red coloration of the skin of the newt, we studied the food habit of the juvenile from the Japanese newt Cynops pyrrhogaster. Sixty-two juveniles were collected in Fukue Island in Nagasaki Prefecture from November 2000 to May 2002 and divided into 2 groups according to the snout-vent length (SVL). Over 400 prey animals were obtained from the juveniles by stomach flushing. In the larger group (SVL>30.0mm), Collembola (45.4%) and Acari (12.6%), which are very common species of soil animals, were the prey animals dominant in number. In the group with the smaller SVL (<29.9mm), Collembola (30.4%) and Acari (25.4%) were in number as well. We also studied the food habit of the Japanese clouded salamander, Hynobius nebulosus. In the salamander, Doratodesmidae (56.5%) and Amphipoda (13%) were the prey animals dominant in number. Our results, taken together, suggest that the Japanese juvenile C. pyrrhogaster does not change its food habit as it grows, and that it eats soil animals common in its habitat. Moreover, the food habit of juvenile C. pyrrhogaster differs from that of H. nebulosus, although the juveniles of both species live in the same area."

The full report, which I think you'll find very, very interesting (as I did

), can be found here:

http://www.jstage.jst.go.jp/article/zsj/20/7/855/_pdf

By the way, I have since obtained the full report: An Ultrastructural and Carotenoid Analysis of the Red Ventrum of the Japanese Newt, Cynops pyrrhogaster (abstract shown in my initial post). But I don't have a link for a Web copy of it to share with you.

(Message edited by TJ on December 03, 2003)

 

[sergé]

Crusteaceans play an important rol in belly coloration. Several people in Euprope have this expericence with raising Triturus species, which also only get nice orange bellies when they are raised with for instance Daphnia or other crustaeceans. It only goes to show that we still tend to use too little variation in food resources. Especialy red or bright orange coloration of bellies is very depended of food resources. Because even in nature you can find animals with yellow or dull orange coloured bellies
Some people have even tried to use powder of red peppers...in Bombina (Fired bellied toads which have the same problems).

 

[paul]

Interesting information which supports what I found.
I think, sheet lice have a comparable effect.
I also feed my juvenile with Thermobia domestica. Those I only feed with Koi fish feed sticks, which has a high level of Carotin.
Paul