UROLITH PREVALENCE AND RISK FACTORS IN ASIAN SMALL-CLAWED OTTERS ( AONYX CINEREUS)

Uroliths (urinary stones) are routinely found in both domestic and exotic animals kept under human care. In zoos, Asian small-clawed otters (ASCOs, Aonyx cinereus) have been identified as being particularly prone to this disease. Risk factors are thought to be nutritional; however, recommendations contradict each other, depending on which physiological model was used. Our study aimed to determine the prevalence of uroliths in ASCOs under human care and to evaluate which feeding patterns and nutrients may be linked to their occurrence. Questionnaires were sent to zoos holding ASCOs in North America (AZA), Europe (EAZA), and Japan and Southeast Asia (Asia) asking about diets and medical histories of all ASCOs alive or dead within the last 10 yr. A risk-factor style binary logistic regression was conducted on these data. A total of 94 questionnaires were received; however, only 56 were usable (15.6% return rate), representing 161 otter cases. AZA had the significantly highest incidence of kidney stones (62.8%), followed by EAZA (12.9%) and Asia (9.4%). Age and calcium were risk factors, whereas crude protein and sodium were protective. Therefore, calcium may need to be controlled within their diet. A diet high in fish and crustaceans may be beneficial and is consistent with wild ASCO diets. The feline model may be the best choice out of other models; however, many factors cannot be compared with ASCO, such as urinary pH.