Use of Fresh Plant Materials in Feeding and Management of Captive Animals Should be Science-Based
Abstract
Over the past 25 years, there has been an increased use of fresh plant materials in captive animal management. These plant materials, including leaves, branches, flowers, and fruits in various stages of development, may serve as primary nutrient sources or as supplements to the diet, or they may be used as sources of environmental enrichment, providing perching sites, manipulable objects, or enclosure plantings that increase the natural appearance of exhibits.8,11
Most institutions employ the use of indigenous plant species collected from various sources in the facility’s immediate surroundings. Other institutions have combined these sources with plants identified in a target animal species’ home range, or documented the natural diet, and cultivated those plants for routine harvesting and use.
Many animal species (e.g., koalas) cannot be maintained in captivity without adequate quantities of appropriate (i.e., species, stage of development) browse plants.18 Other animals demonstrate positive objective responses to inclusion of browse plants as a significant component of the daily ration (e.g., giant eland, giant pandas).4,12
Captive-born animals do not have the same experiences as wild animals in food selection and avoidance of potentially hazardous material.11 The presumption that naïve animals are innately capable of recognizing nutrient concentrations or toxicants within a food source (nutritional wisdom) is not supported by evidence.10,17
As a consequence, with the increased use of plants in animal diets, our industry has reported an increased incidence of morbidity and mortality associated with inappropriate or incompatible pairings of animals with plants.1-3,6,7,9,13,15,16,19
The use of fresh plant materials in animal diets brings with it inherent risks that are not present with (or are different than) commercially available foods. The perceived benefits of using fresh plant materials should be evaluated against those risks. Personnel making the decisions to include fresh plant materials in an animal care program must fully understand and assume those risks and bear the burden of those decisions. These staff members must have an intimate understanding of the interactions between both the plants and the animals consuming them. They would not seek out that expertise from producers of commercial produce or harvested forages (e.g., hays), nor should they look for those decisions to be made by the “producers” of these browse materials.
Animal-care personnel, preferably those with strong backgrounds in the sciences of animal nutrition and plant physiology, should scrutinize these browse plants with all the safeguards (and more) used to evaluate any food item used for feeding captive wildlife.5,14 Plant species, stage of growth, growing conditions, exposure of this plant or plants in the vicinity to pesticides, herbicides, or environmental pollutants, and handling of the materials post-harvest are just a few of the issues that should be evaluated before plant materials are approved for use with the targeted animal species.
As with any other aspect of captive animal care, diets, including the use of plant materials for any purpose, require continued scrutiny and daily management. Appropriate diets are the foundation of proper animal care, and it is unethical to acquire and exhibit wild animals without the supervision of scientifically trained and qualified personnel making critical management decisions that ultimately affect animal health and welfare.
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