Proximate, vitamins A and E, and mineral composition of free‐ranging cotton mice (Peromyscus gossypinus) from St. Catherines Island, Georgia

Abstract

Although rodents are an integral part of numerous carnivore diets, there is little published information regarding nutrient composition in free-ranging mice for comparison with laboratory-reared prey. Cotton mice (Peromyscus gossypinus, n ¼ 6) were captured on St. Catherines Island, Georgia, and analyzed for water, ash, protein, and fat content (proximate constituents), as well as minerals and the fatsoluble vitamins A and E. The overall body composition (mean7SD: 65.8%71.9% water, 10.9%72.2% ash, 56.4%74.1% protein, and 27.2%73.9% fat) was similar to published values for adult laboratory mice (Mus domesticus). The macro-(Ca, K, Mg, Na, and P) and trace (Cu, Fe, Mn, and Zn) mineral levels were also similar to previously reported values for laboratory mice, and in general met or exceeded the established nutrient requirements for domestic carnivores. Vitamin E ranged from 77 to 170 IU/kg dry matter (DM) in these mice-again, similar to values previously quantified in laboratory mice. However, the vitamin A concentrations (21,94776,893 IU/kg DM) in the free-ranging mice were consistently and substantially lower than values reported for whole laboratory mice. To our knowledge, this is the first quantification of vitamin A in free-ranging mice used as prey by carnivores. While other nutrients measured were similar between captive-reared and free-ranging mice, the current data suggest the need for further investigation of vitamin A nutrition in the development of optimal diets for carnivores in captivity.

Environmental and prey‐based factors underpinning variability in prairie dogs eaten by black‐footed ferrets

“…In any case, both species appear to contain adequate vitamin E as food for ferrets compared to estimated dietary requirements of mink or domestic carnivores (~30 IU/kg DM for maintenance and 80 IU/kg DM for reproduction; National Research Council 1982, 2006). While prairie dog values were similar to those measured in free‐ranging cotton mice (Thomas et al 2004) and within ranges reported for medium‐sized prey species such as rats or rabbits, these vitamin E levels measured are markedly higher than vitamin E concentrations reported in domestically reared small prey rodents (mice, hamsters; Dierenfeld et al 2002). Prey sourcing therefore requires careful consideration for captive carnivore diet formulation.…”

“…Without knowledge of this component's contribution, interpretation of vitamin A intake by ferrets outside of the breeding season based on prairie dog carcass composition alone would be misleading. Very few values for vitamin A content in whole rodent prey are found in the literature (Douglas et al 1994, Clum et al 1996, Dierenfeld et al 2002; captive-reared rodents consistently demonstrated high and widely varying levels of this nutrient, especially compared to values measured in free-range cotton mice (Peromyscus gossypinus; Thomas et al 2004). The detection of vitamin A in some stomach samples was unexpected as plants contain no preformed vitamin A but rather carotenoid precursors utilized by herbivores to convert into active forms in the intestinal tract.…”