Nutrient Composition of Locally Available Browses Consumed by Matschie’s Tree Kangaroos (Dendrolagus matchiei) in Six North American Zoological Facilities

Abstract

Locally collected browses (n=17 spp.) consumed by Matschie’s tree kangaroos (Dendrolagus matschiei) in 6 North American zoological institutions were analyzed for comparison with native plants eaten by this species in Papua New Guinea to evaluate dietary suitability. Primary nutrients including crude protein and fat, fiber, starch, non-fiber carbohydrates, and ash were determined using standard analytical methods for forages. Macrominerals calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na) and sulfur (S), as well as trace elements copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn) were quantified in leaf (n=18), flower (n=1), twig (n=9) and bark (n=6) samples. Tannin content was estimated through the bovine serum albumin methodology. On a dry matter basis (DMB) , foods averaged (± SD) moderate protein (12 ± 5%) and soluble carbohydrate (27 ± 12%) content, along with low starch (1 ± 1%) and crude fat (3 ± 2%) values, and moderate to high values in fiber fractions (neutral detergent fiber 49 ± 15%, acid detergent fiber 33 ± 13%, lignin 11 ± 5%). Macromineral concentrations (Ca 2.2 ± 1.6%, P 0.2 ± 0.1%, Mg 0.3 ± 0.2%, K 1.5 ± 0.6%, Na 0.03 ± 0.04%, S 1.2 ± 1%) and select trace minerals were within anticipated ranges (Cu 11 ± 5 mg/kg, Mo 1 ± 1 mg/kg and Zn 33 ± 18 mg/kg); exceptions Fe (122 ± 11 mg/kg) and Mn (51 ± 81 mg/kg) were considered on the high end of dietary adequacy for most herbivores. Leaves differed significantly from woody parts for all proximate nutrients, as well as K, S, Fe, and tannin content. Consumed in a 50:50 DMB ratio, locally available browses provide similar nutrient profiles as plants eaten by free-living tree kangaroos. Combined data provide information useful in establishing nutrient targets for dietary development, leading to improved health, welfare, and feeding management of tree kangaroo populations under human care.