Go with your gut: Digestibility and digestive function of two arid-zone Australian murids, Pseudomys australis and Notomys alexis.

Spinifex hopping-mice (Notomys alexis) and plains mice (Pseudomys australis) are able to successfully occupy arid zones of Australia. We studied the digestive parameters and energy assimilation of captive spinifex hopping-mice and plains mice. The experiment consisted of six diets fed to the animals for periods of 12days per food type. On a dry matter basis, the plains mice consumed between 2.5 and 7.2% and the hopping-mice between 5.8 and 9.3% of their body mass in food per day. The body mass of the spinifex hopping-mice increased significantly on the sunflower seed diet, while body mass did not change significantly for the plains mice on any diet. Apparent digestibility of macronutrients was similar in the hopping-mice and plains mice when maintained on the same diet, however digestibility of total micronutrients differed. Maintenance energy requirements for the plains mice were 529kJkg-0.75d-1 and spinifex hopping-mice 550kJkg-0.75d-1. Spinifex hopping-mice and plains mice are able to exploit a range of food items and efficiently digest macronutrients, to ensure they meet their nutritional needs, an ability they require in the variable arid environment. The information gained in this study increases the paucity of information on Australian native murids, specifically their digestive function and energy requirements, and will aid captive murid management. The study will allow future expansion into field studies, to aid the conservation of wild rodent diets and nutrition of arid zone murids.

Dead mouse hopping: Tyzzer's disease in spinifex hopping-mice (Notomys alexis).

Tyzzer's disease is caused by Clostridium piliformes and affects a wide range of domestic and wildlife species. Non-descript signs, if any, and a short incubation period make Tyzzer's disease difficult to diagnose and treat before death occurs. Here we describe an unexpected outbreak of Tyzzer's disease in a colony of native Australian spinifex hopping-mice (Notomys alexis). In this study captive hopping-mice were used in a nutrition trial (n=11), and others were housed in close proximity (n=4). During the nutrition trial, two hopping-mice exhibited signs of lethargy and diarrhoea, and were removed from the trial but died soon after. Other hopping-mice exhibited limited clinical signs of ill-health, prior to their death. In total four animals were found dead, and another seven were euthanised, to prevent a potential disease outbreak. Tyzzer's disease was confirmed post-mortem using histopathology silver stain to detect the bacilli-shaped bacteria (C. piliformes) in liver tissue of two hopping-mice. After Tyzzer's disease was confirmed enhanced infection control measures were implemented. Enhanced control measures included the use of metal containers for food and water, sick animals were fed and cleaned last, 5% sodium hypochlorite was used as the cleaning agent, stricter hand washing protocols and a change of gloves between feeding animals, and strict limits on persons entering the facility. Control measures for this disease should include euthanasia of any animals suspected to be infected, complete disinfection of all enclosures and associated equipment using sodium hypochlorite. Molecular methods could be employed to ensure complete removal of bacterial spores prior to new animals being moved into enclosures where affected animals were housed. Tyzzer's disease is a fast spreading disease which can cause detrimental effects to captive colonies and their environment. Captive colonies subjected to stress are at risk of Tyzzer's disease. Appropriate quarantine procedures, close montoring and quick action in response to signs of illness will ensure Tyzzer's disease outbreaks do not occur.

Haematology and serum biochemistry in captive Australian native murids: black-footed tree-rat (Mesembriomys gouldii) and greater stick-nest rat (Leporillus conditor).

The black-footed tree-rat (Mesembriomys gouldii) and greater stick-nest rat (Leporillus conditor) are near threatened and vulnerable native Australian murids. There is a paucity of health and welfare knowledge for these species and native murids in general. In this paper we aimed to address this deficiency in knowledge by describing some key haematological and blood biochemistry parameters for these species. Haematology and blood biochemistry data were obtained from clinical histories of the two murid species held in captivity at Taronga Zoological Park, Mosman, Australia. The data were analysed to establish confidence intervals for each parameter available and leukocyte morphology described. White blood cell counts were higher in females than males. Both species also had high neutrophil:lymphocyte ratios (tree-rat ratios were almost even). Haematocrit was higher in male stick-nest rats than females. Differential leukocyte counts and leukocyte morphology was consistent with previous descriptions in other murids and between individuals. Blood biochemistry values were unremarkable except for the high level of globulin in stick-nest rats. The values provided in the study will add to the knowledge of health data for murids in captivity and aid captive and natural management of Australian native murids.