GLIDERS AND POSSUMS
Sugar gliders (Petaurus breviceps) are most extensively researched and provide a reasonable model for other glider species and possums. Current recommendations for pet sugar gliders focus on preventing metabolic bone disease, obesity and dental disease by feeding properly balanced diets with a commercial product such as artificial nectars with a calcium to phosphorus ratio between 1:1 and 2:1 and 1500 IU∕kg vitamin D3 on a dry matter basis (Ardente et al.
2024; McDermott 2024). Dietary iron overload should also be considered for glider species (Dierenfeld et al. 2006).Daily protein intake for sugar gliders is 10-20% of the diet (roughly 150-200 mg crude protein) which is similar to findings in free-ranging populations (Ball et al. 2009; Dierenfeld and Whitehouse-Tedd 2018). Honey possums (Tarsipes rostratus) lack gastric chief cells, affecting protein hydrolysis, yet their protein synthesis rate is comparable to omnivorous brush-tailed possums (Trichosu- rus spp.) at a rate of 7.7 g kg-0.75 d-1 and 8.5 g kg-0.75 d-1 respectively (Bradshaw and Bradshaw 2009; 2012).
Basal metabolic rates of gliders and possums are generally lower than the standard eutherian BMR (Table 14.2), except for the honey possum which is nearly 60% higher (Bradshaw and Bradshaw 2012). Gliders and possums are prone to obesity, potentially linked to high cholesterol and stress, particularly in Leadbeater’s possums (Gymnobelideus Ieadbeateri) (Steventon et al. 2023). Maintaining balanced diets that account for lower BMRs and nutrient requirements is crucial to prevent metabolic diseases and obesity (Ardente et al. 2024; McDermott 2024).
Artificial nectars are often high in simple sugars and contribute to obesity and dental disease. Narrow-toed feather-tailed gliders (Acrobates pygmaeus) are prone to lipid keratopathy (corneal cholesterol deposits) that may be associated with a diet high in simple sugars (Herrmann et al. 2013; Johnson 2021).
Diets rich in protein and soluble fibre may help mitigate these risks. Some species show potential for fermenting gums due to a large caecum but the digestive abilities of gliders and possums, specifically regarding soluble fibre, remain uncertain (Solden et al. 2015) (Fig. 14.4).The greater glider (Petauroides volans), eastern ringtailed possum (Pseudocheirus peregrines) and common brush-tailed possum (Trichosurus vulpecula) are all foli- vores consuming primarily Eucalyptus leaves and can balance nutritional quality of the leaves against potential costs, such as PSMs (Jensen et al. 2015; Shiffman et al. 2017). However, studies of the western ring-tailed possum (Pseudocheirus occidentalis) indicate folivorous possums may consume a greater diversity of plant species (Mathie- son et al. 2020). This flexibility may improve feeding in managed care and allow free-ranging possums to inhabit a broader range, as climate change threatens their natural habitats (de la Fuente and Williams 2023).
Folivorous species, particularly eastern ring-tailed possums, are prone to dysbiosis and bloating when fed diets high in simple sugars (Tyndale-Biscoe 2005; Chapter 38). Since coprophagy or caecotrophy are naturally practiced in these species, transfaunation is likely an effective means to re-establish microbiome balance (Table 14.3). Omnivorous gliders such as the yellow-bellied glider (Petaurus australis) may be consuming Eucalyptus sap v. foliage yet are still choosing species high in available nitrogen and low in PSMs (Wallis and Goldin- gay 2014). A comparison of these species may indicate those that consume Eucalyptus spp. have a microbiome more like koalas than other possums and gliders (Shiff- man et al. 2017). Regular provision of appropriate native browse and flowers may also increase foraging, benefit- ting long-term welfare (Herrmann et al. 2013).
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