GHENT UNIVERSITY FACULTY OF VETERINARY MEDICINE Academic year 2016 – 2017 NUTRITION OF CAPTIVE AMPHIBIANS by Justin KEULEN Promoters: Dr. Arturo Munoz Literature Review Professor Geert Janssens as part of the Master’s Dissertation © 2017 Justin Keulen ! ! This thesis contains confidential information proprietary to the Universiteit Gent or third parties. It is strictly forbidden to publish, cite or make public in any way this thesis or any part thereof without the express written permission by the Universiteit Gent. Under no circumstance this thesis may be communicated to or put at the disposal of third parties. Photocopying or duplicating it in any other way is strictly prohibited. Disregarding the confidential nature of this thesis may cause irremediable damage to the Universiteit Gent. ! GHENT UNIVERSITY FACULTY OF VETERINARY MEDICINE Academic year 2016 – 2017 NUTRITION OF CAPTIVE AMPHIBIANS by Justin KEULEN Promoters: Dr. Arturo Munoz Literature Review Professor Geert Janssens as part of the Master’s Dissertation © 2017 Justin Keulen ! TABLE OF CONTENT SUMMARY ........................................................................................................................................................ 1 SAMENVATTING .............................................................................................................................................. 2 INTRODUCTION ............................................................................................................................................... 3 LITERARY REVIEW .......................................................................................................................................... 4 1 Nutrient content of feed ........................................................................................................................... 4 1.1 Vitamins ........................................................................................................................................... 4 1.1.1 Vitamin A ................................................................................................................................... 4 1.1.2 Vitamin B ................................................................................................................................... 5 1.1.3 Vitamin D ................................................................................................................................... 6 1.1.4 Other vitamins ............................................................................................................................ 6 1.2 Minerals ........................................................................................................................................... 7 1.2.1 Calcium ...................................................................................................................................... 7 1.2.2 Phosphorus ................................................................................................................................ 7 1.2.3 Other trace elements ................................................................................................................. 7 1.3 Pigments .......................................................................................................................................... 8 1.4 Protein .............................................................................................................................................. 9 1.5 Fat .................................................................................................................................................... 9 1.6 Carbohydrates ................................................................................................................................. 9 1.7 Fiber ............................................................................................................................................... 10 1.8 Probiotics ....................................................................................................................................... 10 2 Effects of nutrition on health and reproduction ..................................................................................... 10 2.1 Health ............................................................................................................................................. 10 2.1.1 Metabolism .............................................................................................................................. 10 2.1.2 Integument ............................................................................................................................... 11 2.1.3 Immune system ....................................................................................................................... 11 2.1.4 Pathologies .............................................................................................................................. 11 2.2 Reproduction .................................................................................................................................. 14 3 Means of feeding and supplementing ................................................................................................... 16 3.1 Feeding .......................................................................................................................................... 16 3.1.1 Invertebrate prey ...................................................................................................................... 16 3.1.2 Vertebrate prey ........................................................................................................................ 17 3.2 Supplementing ............................................................................................................................... 18 3.2.1 Dusting ..................................................................................................................................... 18 3.2.2 Gut-loading .............................................................................................................................. 18 4 Other husbandry related factors ........................................................................................................... 18 4.1 Water ............................................................................................................................................. 18 4.2 Enrichment ..................................................................................................................................... 18 4.3 Ultraviolet (UV) ............................................................................................................................... 19 4.4 Other lightning factors .................................................................................................................... 19 4.5 Temperature .................................................................................................................................. 19 4.6 Disease .......................................................................................................................................... 19 4.7 Toxicities ........................................................................................................................................ 20 DISCUSSION .................................................................................................................................................. 21 REFERENCES ................................................................................................................................................ 24 APPENDIX ...................................................................................................................................................... 30 ! SUMMARY A lot of species in the diverse amphibian class are threatened by different causes. Habitat loss, pollution and disease are some of the processes that cause amphibian declines. In order to reinsure the survival of these endangered amphibian species, captive breeding colonies are maintained. The husbandry of amphibians has however some difficulties. Next to the environmental factors, nutrition is also important in keeping captive amphibians healthy. The content of the diet can have an important impact on amphibian health. Deficiencies and excesses of certain nutrients can cause different disorders that impair amphibian welfare. Vitamin A, vitamin D3 and calcium contents are for example important to prevent lingual squamous metaplasia and metabolic bone disease; two of the most occurring pathologies in captive amphibians. There are however other nutrients important to provide optimal nutrition. Protein is for example important to provide energy and facilitate reproduction. Reproduction is a process that is influential through nutrition. The fecundity should be as high as possible to sustain captive breeding programs by producing offspring. There is however a paucity of information regarding amphibian reproduction; more studies should be executed to determine the effects of certain nutrients. The circumstances of feeding determine more or less the ingestion of food. Time of feeding, size of prey and the environment can play a role in the feeding process. In captivity one should mimic the situation to the wild to provide the best feeding conditions. Overall amphibian nutrition is a difficult subject; amphibians are vulnerable and requirements are mostly unknown;