A new study published by the journal Springer found distinct physiological differences of vitamin D synthesis in three New Zealand species: the kiwi, the tuatara and the sea lion.
Similar to humans, animals must rely on sun exposure or the diet to achieve healthy vitamin D status. A study back in 2015 analyzed the diet of a large, flightless parrot called the kakapo, and found that their main food source, rimu berries, provided these birds up to 18,000 IU per day! A recent study conducted by researchers from New Zealand aimed to discover the physiological differences between vitamin D synthesis in the skin of three very different species of animals.
The researchers included 19 kiwis, a nocturnal, flightless bird, 16 tuataras, a large sun-basking reptile and 10 sea lions. They collected blood and skin samples from all the species and measured UVB exposure in areas these animals were commonly found.
This is what the researchers discovered:
- There was no significant relationship (p = 0.084) between UVB exposure and plasma 25(OH)D3 concentration in kiwi.
- There was no significant relationship (p = 0.186)between UVB exposure and plasma 25(OH)D3 concentrations in the tuatara.
- The sea lion’s’ skin produced vitamin D concentrations that were two times higher than the kiwi and tuatara (see table below).
Vitamin D concentrations after sun exposure.
|Species||Vit D3 (μg/g) at 0 hour UVB||Vit D3 (μg/g) after 8 hour UBV|
The researchers concluded:
“The results from this study show that all three species studied retained the ability to use both dietary and dermal sources of Vitamin D, although there was interspecies variation in the magnitude of dermal synthesis.”
Kale, M. et al. Interspecies differences in plasma concentrations of 25-hydroxyvitamin D3 and dermal Vitamin D synthesis of kiwi (Apteryx mantelli), tuatara (Sphenodon punctatus), and New Zealand sea lions (Phocarctos hookeri). Springer, 2017.