Assistant Laboratory Animal Technician (ALAT) Practice Exam

Which vitamin cannot be synthesized by non-human primates (NHPs) or guinea pigs?

1. Vitamin D

2. Vitamin B12

3. Vitamin A

4. Vitamin C

The correct answer is: Vitamin C

Non-human primates and guinea pigs are unable to synthesize vitamin C due to a genetic mutation that affects the enzyme needed for its production, specifically L-gulono-gamma-lactone oxidase. This deficiency means that they must obtain vitamin C through their diet, as it is an essential nutrient in preventing scurvy and supporting various biological functions such as collagen synthesis, antioxidant activity, and immune function. Other species, including humans, also rely on dietary sources for vitamin C since they share this inability to synthesize it, making this vitamin unique in its necessity for these animals. In contrast, vitamin D can be synthesized in the skin through exposure to sunlight, while both vitamin B12 and vitamin A can be derived from dietary sources or precursors, allowing some species, including many non-human primates, to meet their needs without solely depending on their diets.