Serum nutritional profiles of free-ranging Alouatta caraya in northern Argentina:: Lipoproteins; amino acids; vitamins a, d, and e; carotenoids; and minerals

Quantifying circulating nutrient concentrations in sera of free-ranging subjects will help to establish a basis from which we can evaluate the nutritional status and needs of the captive population. We collected serum samples from 26 free-ranging black-and-gold howlers (Alouatta caraya) in San Cayetano forest in northern Argentina. We analyzed them for concentrations of lipoproteins; amino acids; vitamins A, D, and E; carotenoids; and minerals. There are a few significant differences between sexes in concentrations of high-density lipoprotein cholesterol, certain amino acids, vitamin E, lutein + zeaxanthin, and copper. Most nutritional parameters are similar to the ones measured in free-ranging Mexican mantled howlers (Alouatta palliata mexicana) and in captive New World primates (NWPs). Carotenoid, vitamin D, and phosphorus concentrations are the exceptions. Carotenoid concentrations are higher in free-ranging Alouatta caraya than reported for other free-ranging and captive species. Vitamin D concentrations are 14 times greater in the free-ranging black-and-gold howlers than in captive NWPs. Phosphorus concentrations are also higher than expected and higher than typically occur in captive primates, leading to a 1:1.6 calcium:phosphorus ratio. Because we based our study on a small number of free-ranging howlers, additional samples from different regions and throughout the year would better define desirable nutritional parameters for captive howlers.