IUCN/SSC Otter Specialist               Otters in Zoos, Aquaria, Rehabilitation, and Wildlife 
                            Group                                                                Sanctuaries Task Force            
                   
                   
                   
                                                 Summary of Nutrition Guidelines for  
                             Otters in Zoos, Aquaria, Rehabilitation, and Wildlife Sanctuaries 
                                       B. Henry, M. Maslanka, K. Heuer, J. Reed-Smith, G. Nidasio, 
                                                                       2012 
                                                                  Published by: 
                        IUCN/SSC Otter Specialist Group, Otters in Zoos, Aquaria, Rehabilitation, and Wildlife 
                                                          Sanctuaries (OZ) Task Force 
                                  http://www.otterspecialistgroup.org/Library/TaskForces/OCT.html 
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                   
                   
                   
                   
                   
                   
                   
                   
                                  Photograph: Spotted-necked otter, Jenna Kocourek, Little Rock Zoo 
                  IUCN/SSC Otter Specialist Group/OZ Task Force/Nutrition 2012 Ver. 2                                       Page 1 
                   
                            IUCN/SSC Otter Specialist               Otters in Zoos, Aquaria, Rehabilitation, and Wildlife 
                            Group                                                                Sanctuaries Task Force            
                   
                  CONTENT 
                   
                   
                          1. OTTER NUTRITION 
                   
                                   1.1 NUTRIENT REQUIREMENTS 
                                   1.2 ENERGY INTAKE AND FOOD AMOUNT 
                                   1.3 CHANGING NUTRIENT REQUIREMENTS 
                   
                          2. DIETS AND FEEDING 
                           
                                   2.1 INGREDIENTS 
                                   2.2 SUPPLEMENTATION 
                                   2.3 SPECIAL CONCERNS  
                                   2.4 FEEDING SCHEDULE 
                                   2.5 SAMPLE DIETS 
                   
                          3. NUTRIENT DESCRIPTION 
                   
                          4. REFERENCES
                  IUCN/SSC Otter Specialist Group/OZ Task Force/Nutrition 2012 Ver. 2                                       Page 2 
                   
                            IUCN/SSC Otter Specialist               Otters in Zoos, Aquaria, Rehabilitation, and Wildlife 
                            Group                                                                Sanctuaries Task Force            
                   
                  1. OTTER NUTRITION 
                       
                      Adequate nutrition is an essential for optimal husbandry. Improper feeding can severely 
                  affect health and well-being of captive animals (Hatt 2000). Improved nutrition has often 
                  positive effects on longevity, disease prevention and resistance, growth and reproduction 
                  (Ratcliffe 1963, Dierenfeld 1997). 
                      A formal nutrition program is recommended to meet the behavioral and nutritional needs 
                  of all animals. Diet formulation criteria should address the otters’ nutritional needs, feeding 
                  ecology, as well as individual and natural histories to ensure that species-specific feeding 
                  patterns and behaviors are stimulated. In specific, diet formulation should account for animal 
                  preferences, body  weight, exercise, physical condition, environmental/seasonal changes, 
                  behavioral considerations, diet item availability, gastrointestinal tract morphology, as well as 
                  the actual nutrient requirements.  
                       
                       
                  1.1 NUTRIENT REQUIREMENTS 
                       
                      Metabolic studies examining the exact nutrient requirements have not been done for any 
                  otter species. Conducting these metabolic studies, which require collection of feces, urine, and 
                  blood samples under laboratory conditions, to assess nutrient requirements for wild species are 
                  difficult. For this reason, target nutritional values for otters are based on several sources and 
                  use domestic and other small carnivore pelt producing species as models.  
                      The cat is typically used to establish nutrient guidelines for carnivorous animals. The 
                  National Research Council (NRC 2006), Association of American Feed Control Officials (AAFCO 
                  1994), and Waltham Center for Pet Nutrition (Earle & Smith 1993) have provided 
                  recommendations for cats. A limited amount of information is provided by the NRC publication 
                  for mink and foxes (1982), which represents the requirements of another mustelid species. In 
                  addition, target nutrient values for one of the species in question has been reported elsewhere 
                  (Maslanka and Crissey 1998). Table 1 lists dietary nutrient ranges for otters, based on a variety 
                  of sources. 
                      The mink as a model animal for otters was tested with Lutra lutra and showed a lower 
                  digestive efficiency and faster passage times for the otter (Ruff 2007) –suggesting use of the 
                  higher amounts of given ranges for mink should be used for otters. 
                      Another method of assessing nutrient requirements is to consider natural feeding ecology. 
                  Presuming the unproven assumption of diet optimality in free-ranging animals, as the optimal 
                  foraging theory suggests, appropriate approximate nutrient requirements can be derived by 
                  analyzing in-situ diets (Dierenfeld 1994, Krebs et al. 1978). Insight into problematic nutrient 
                  ranges in ex-situ nutrition (in zoos etc.) can be found through comparing the ex-situ with in-situ 
                  nutrient ranges. 
                  IUCN/SSC Otter Specialist Group/OZ Task Force/Nutrition 2012 Ver. 2                                       Page 3 
                   
                            IUCN/SSC Otter Specialist               Otters in Zoos, Aquaria, Rehabilitation, and Wildlife 
                            Group                                                                Sanctuaries Task Force            
                   
                  Table 1: Target nutrient ranges for otter species (dry matter basis). 
                   
                   Nutrient                                                                    Otters1 
                   Protein (%)                                                               19.7-32.5 
                                                                                                     2a
                   Fat (%)                                                                    9.0-30  
                   Linoleic Acid (%)                                                          0.5-0.55 
                   Vitamin A (IU/g)                                                           2.44-10 
                   Vitamin D (IU/g)                                                           0.25-1.0 
                   Vitamin E (mg/kg)                                                           27-120 
                                                                                                     1b
                   Thiamin (mg/kg)                                                            1.0-5.6  
                   Riboflavin (mg/kg)                                                         1.6-4.25 
                   Pantothenic acid (mg/kg)                                                    5.0-8.0 
                   Niacin (mg/kg)                                                              9.6-60 
                   Pyridoxine (mg/kg)                                                          1.6-4.0 
                   Folacin (mg/kg)                                                             0.2-1.3 
                   Biotin (mg/kg)                                                            0.07-0.12 
                   Vitamin B  (mg/kg)                                                        0.02-0.035 
                             12
                                                                                                      1c
                   Calcium (%)                                                               0.29-1.0  
                                                                                                      1c
                   Phosphorus (%)                                                            0.26-0.8  
                   Potassium (%)                                                               0.4-0.6 
                   Sodium (%)                                                                 0.05-0.4 
                   Magnesium (%)                                                             0.03-0.08 
                   Iron (mg/kg)                                                                80-114 
                   Zinc (mg/kg)                                                                50-94 
                   Copper (mg/kg)                                                              5.0-8.8 
                   Iodine (mg/kg)                                                             0.35-2.2 
                   Selenium (mg/kg)                                                            0.1-0.4 
                  1 Cat NRC (2006), Legrand-Defretin & Munday (1993), Cat AAFCO (1994); Maslanka & Crissey, 1999; Mink NRC 
                  (1982); Fox NRC (1982) (for mink and fox NRC protein is range of growth and maintenance, vitamins are for 
                  growth, and minerals for growth and maintenance).  
                  1a
                    Lewington (2002) indicated that lactation demand on female mink (Mustela) may require up to 45.7% CP on a 
                  dry matter basis (based on a calculated 83% protein digestibility). 
                  1b
                   Blomqvist (2001) has indicated that wolverines (Gulo gulo) may have a higher requirement for thiamin than other 
                  mustelids. 
                  1c
                    Authors of this chapter would caution feeding diets with 0.29% calcium and 0.26% phosphorus as the Cat NRC 
                  2006 suggests. 
                  IUCN/SSC Otter Specialist Group/OZ Task Force/Nutrition 2012 Ver. 2                                       Page 4