A unique effort is being co-ordinated in Manchester, to save a rare amphibian in Costa Rica. John Courteney-Smith of Arcadia Reptile reports on this global scheme, which involves a range of key partner organisations and supporters.
The D3 Cycle Explained
We at Arcadia Reptile are passionate in our belief that through continued education and scientific research, we can improve the health and wellbeing of captive reptiles all over the world.
It is safe to say that we as an industry can no longer label reptiles as simply, “Forest or Desert”, we know far more about reptiles and their complicated relationship with the sun than ever before. There are key indicators in every wild animal that will help you find and maintain the correct “life support systems”.
Reptiles rely on heat, light, UVA/UVB, food and water to sustain them and further the bloodlines. We as responsible keepers should do all that we can to replicate these wild indicators as closely as current tech allows. At Arcadia Reptile we are proud to offer our customers access to more FREE science and emerging thoughts and tech than any other brand. We’re determined to start our “Revolution In Reptile Care” and as part of our commitment to education, thought it would be good to explain what is referred to as, ‘The D3 cycle’. Arcadia Reptile, Pure Science, Pure Care!
The D3 Cycle is a chemical and hormonal change in the body of an animal, which goes on to produce vitamin D3. This is a biological process that is dependent on many external factors including access to natural light, heat, cool and rest. A good diagram of the various processes can be easily found online, www.uvguide.co.uk is a great source of helpful information and independent scientific data. It is worth noting that although vital to the well being of reptiles, UV exposure plays many more roles in the body than just the D3 cycle. Impacts on sight, breeding and mental well being are all documented and are undergoing continued research.
This amazing process begins when a cholesterol called pro vitamin D(7DHC) is produced in the animal’s skin (it is a natural process in humans too). When this cholesterol is exposed to natural light (including light in the UVB wavelength (290-315nm)), this cholesterol is turned in the skin membrane into pre vitamin D.
After exposure to warmth, this newly manufactured pre vitamin D is converted (in the skin membrane) into vitamin D3. It is essential to have this heating up period alongside UV radiation. Vitamin D3 is then sent out into the blood plasma and is bound with a vitamin D binding protein. This is then carried to the liver where this part of this vitamin is converted to a hormone called calcediol (25-hydroxy vitamin D3).
The blood carries this calcediol all around the body and into the kidneys where some of the hormone is turned into another hormone, called calcetriol. This compound then plays an essential role in calcium metabolism and controls the levels of calcium in the blood. Calcetriol also plays a huge role in the immune system and the cardiovascular system. It has been shown to lower the risk of cancers in the body and skin.
So we can see that exposure to natural sunlight is only the start of this amazing ability in reptiles and humans alike, to turn sunlight into life saving vitamins. This D3 cycle is dependent on the completion of the D3 cycle. If part of the cycle is missed out then the cycle cannot be completed properly. Changes and reactions would also be unable to be completed properly. This would result in an under provision of essential vitamins and hormones, and if supplementation were not used, a calcium crash could happen.
© John Courteney-Smith
Taken from “lighting for crepuscular and understory reptiles by John Courteney-smith”
The use of a solar meter is in our mind a very powerful tool in ensuring that your animals receive the exposure to UVB that they would be exposed to in the wild. The Solar meter 6.2 is a good guide as to the level of UVB and will also show the relative decay of a lamp over time. The solar meter 6.2 can be used more accurately to set a usable photogradient whether you use the full sun or partial shade method of illumination.
All technology has limitations and one limitation with all light meters is that they measure wavelengths from different light sources in different ways. It is for this reason that our advice is to not use a 6.2 when measuring a Mercury vapour lamp or metal halide alone, you will get an artificially low result.
The Arcadia reptile lighting guide contains uw/cm2 recommendations. These guidelines only apply when measured with a 6.2 and using Arcadia Reptile fluorescent lamps. Other forms of lighting may show lower results that is provided in reality.