Diet, nutrition and haematology of Dasyurid marsupials

Abstract

This thesis examines aspects of the biology of six Dasyurid species, which are a family of insectivorous and/or carnivorous Australian marsupials. In particular diet, nutrition and haematology were studied. Diet and nutrition were studied to obtain information on diet choice by translocated animals and diet digestibility in captive animals. Haematology was studied in captivity as it is associated with clinical health and is influenced by nutrition. The six species used for the study were part of captive colonies housed at the University of Western Sydney, the University of Sydney, Alice Springs Desert Park, Australian Ecosystems Foundation Inc., and Featherdale Wildlife Park. The broad aim of the study was to aid current wildlife management practices and future conservation efforts (such as reintroduction and translocation programs) for these six species and other marsupial species in Australia. Examination of the diet of a population of translocated red-tailed phascogales (Phascogale calura) at Alice Springs Desert Park showed that they are primarily insectivorous with 92.6% of all scats containing arthropods. They are also opportunistic predators within the park, consuming birds (51.6%), small mammals (33.3%) and on occasion reptiles, and plant material (27.4%). A seasonal variation in diet was found between spring and summer, due to a larger portion of birds present in the diet in spring. The red-tailed phascogales were able to exploit a number of prey types and it is therefore likely that they would survive a 'hard' translocation into the wild provided the site chosen has an adequate food supply. Investigation of the gastrointestinal tract of the kultarr (Antechinomys laniger) shows that on gross examination it is simple with no differentiation between the small and large intestine, and lacked a caecum. Mean gross length of the kultarr digestive tract was 165.2 ± 32.1 mm. Microscopically, the tissues appeared healthy with cell types similar to other mammals. Rate of passage through the kultarr digestive tract was rapid, measuring 1.6 ± 0.2 h and mean retention time 3.9 ± 1.2 h. The rapid transit time was consistent for an animal of equivalent body mass, dietary preference and gastrointestinal tract morphology. Study of nutrition in red-tailed phascogales and kultarrs showed apparent digestibility values were above 81% for dry matter, energy, protein and lipids on a number of captive fed diets. No significant difference was found between phascogales and kultarrs when maintained on the same diet for apparent digestibility of dry matter, energy, protein and lipids. Maintenance energy requirements were determined to be 954 kJ kg0.75 d-1 for the red-tailed phascogale and 695 kJ kg0.75 d-1 for the kultarr. Digestion studies undertaken on stripe-faced dunnarts (Sminthopsis macroura) and fat-tailed dunnarts (Sminthopsis crassicaudata) showed that depending on the diet, the digestible energy intake of the stripe-faced dunnart ranged from 359 to 816 kJ kg -0.75 d-1 and digestible intake ranged from 542 to 990 kJ kg -0.75 d-1 for the fat-tailed dunnarts. Both dunnart species had varied absorption of minerals with higher values observed for Na, P and K compared to the other minerals studied. The morphology of the gastrointestinal tracts of both dunnart species were simple and consisted of a unilocular stomach and relatively uniform intestine, like that of the kultarr. The length of the intestine of the stripe-faced dunnart ranged from 84 to 129 mm and that of the fat-tailed dunnart 78 to 131 mm. Fat-tailed dunnarts need to consume more nutrients per unit of body mass for maintenance in captivity compared with stripe-faced dunnarts. Studying digestibility in a larger Dasyurid species, the eastern quoll (Dasyurus viverrinus), showed they had high apparent digestibility values for dry matter, gross energy, protein and lipids (>84%). There was a significant difference in apparent digestibility of dry matter, gross energy and protein between the two diets provided: kangaroo mince and chicken necks. Analysis of blood parameters in the eastern and spotted-tailed quoll provided new data for blood chemistry and differential white cell values. For many of the parameters, blood chemistry results were comparable to other marsupials and no significant differences bilirubin, glucose, creatinine and sodium levels in the eastern quoll. Generally higher levels for these parameters were observed in summer; however, in autumn (southern hemisphere) sodium levels were significantly higher. Eastern quolls one year of age and under had significantly (P

Date of Award	2012
Original language	English