Kaela schreef: ↑vr 28 jan 2022, 09:44
Ik weet niet beter dan dat haren en veren zonlicht naar de huis transporteren en voor de aanmaak van vitamine d zorgen. Anders zou het gros van de wilde dieren een zwaar vitamine d tekort hebben.
Vogels hebben alleen blote voetjes, de rest is allemaal veer. Elke vogelspecialist adviseert om je huiskamervogel regelmatig bloot te stellen aan zonlicht. Dan hoef je je direct geen zorgen meer te maken om vitamine D.
My two cents: met honden die dagelijks uitgelaten worden zou ik me niet zo rap zorgen maken. Natuurlijk moet er (zeker in de winter) een deel via voeding komen. Maar de zon, die is echt een belangrijke factor.
Maar kunnen honden dan zelf vit D maken? Ik heb niet alle links van Lizzy gelezen maar hier staat:
https://onlinelibrary.wiley.com/doi/ful ... /jpn.13259
Dogs and cats, unlike other mammals such as sheep, cattle, horses, pigs, rats and humans, are not able to synthesize vitamin D in the skin through sun exposure (How, Hazewinkel, & Mol, 1994; Morris, 1999). Therefore, these species are dependent on the dietary intake of vitamin D. This can be explained by the evolutionary adaptation of these animals, as cats are considered strict carnivores and dogs carni-omnivores adapted to the consumption of prey animals. These prey animals store vitamin D in the liver, so if liver is consumed regularly, vitamin D deficiency is not expected. If, for a long period, no prey is consumed, dogs and cats can use their vitamin D stores, because it is a fat-soluble vitamin therefore the body can store it. Due to this evolutionary adaptation, carnivores are also considered more resistant to vitamin D poisoning than omnivorous animals, due to their adaptation to ingestion of large amounts (Morris, 2002a). In other species, cutaneous biosynthesis of vitamin D occurs through the conversion of 7-dihydrocholesterol to cholecalciferol (vitamin D3) when the skin is exposed to ultraviolet B rays. Dogs and cats however have a low ability to perform this synthesis as a result of the high activity of the enzyme 7-dihydrocholesterol-Δ7-reductase, which converts 7-dehydrocholesterol into cholesterol, reducing concentrations of this vitamin D precursor in the skin and preventing its conversion to cholecalciferol (How et al., 1994; Morris, 1999).