Obesity in Reptiles | Vetlexicon
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Obesity

ISSN 2398-2985


Introduction

  • Obesity is defined as abnormal or excessive fat accumulation that may impair health. The British Small Animal Veterinary Association have a 1-9 body condition score scale for dogs and cats. BCS of 8 & 9 are considered obese with at least 30% excess weight. 
  • The BSAVA Statement on obesity: ‘In companion animals, obesity has a significant adverse effect on health and welfare including associations with various additional and often concurrent conditions or diseases, reduced life expectancy, functional impairment and poor quality of life.
  • Cause: overfeeding (too much and/or too often), excessive fat content in the diet, lack of opportunity to exercise. Less commonly caused by hormonal imbalances.
  • Signs: excessive fat under skin and intra-abdominal/intra-coelomic, lethargy, possibly impaired mobility, co-morbidities, eg heart disease.
  • Diagnosis: physical examination, visual inspection/body condition scoring (BCS).
  • Treatment: modify diet, reduce high calorie foods, increase exercise, provide environmental enrichment.
  • Prognosis: varies according to presence of comorbidities - can be associated with hepatic lipidosis. Good with owner engagement.
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Presenting signs

  • Obesity.
  • Fat deposits may be visible or palpable.
  • Lethargy.
  • Reduced inclination to move around.
  • Co-morbidities such as heart disease Heart disease, pododermatitis, hepatic lipidosis Hepatic lipidosis.

Acute presentation

  • Usually a chronic condition.
  • Acute signs are rare.
  • Animals may be presented as part of a routine check-up, but often are suffering from co-morbidities before being presented to the clinic.

Geographic incidence

  • Worldwide in captive reptiles.

Age predisposition

  • More common in adult reptiles.
  • There is no direct correlation with age but as mobility decreases with age, then obesity can become more prevalent.

Gender predisposition

  • Female reptiles may be predisposed obesity if not breeding normally.
  • Reptiles are rarely routinely neutered.

Seasonal predisposition

  • Reptile species that hibernate may lay down fat for energy provision during the winter. The liver is a major fat resource in Chelonia for example.

Breed/Species predisposition

  • Obesity is commonly a result of overfeeding in conjunction with reduced energy expenditure. This is a common problem in snakes, a species that is often kept in suboptimal conditions without the ability to stretch its entire body all at once.
  • Certain species are more prone to obesity than others:
    • Pythons , boas , vipers, tegu lizards , monitors and other heavy-bodied lizards, crocodiles, snapping turtles, and alligator snappers tend to be sedentary.
    • Most of these species are opportunistic ambush feeders and relatively inactive.
  • Obesity is less likely in active reptiles, such as garter snakes , racers, many elapids, anoles , and many aquatic and semi-aquatic turtles .
  • Many reptiles are prone to storing fat in their coelomic cavities in fat pads; they also store lipids in the liver which can lead to hepatic lipidosis Hepatic lipidosis.
  • Females may utilize stored fat for folliculogenesis.
  • Bearded dragons Bearded dragons and snakes are the most common reptile species affected by obesity in the UK.

Cost considerations

  • Minimal, however obesity can require veterinary input to formulate a healthy diet with follow up appointments to monitor response.

Special risks of co-morbidity of obesity and inappropriate diet

Pathogenesis

Etiology

  • Energy intake is significantly higher than energy expenditure.
  • Obese reptiles store fat in deposits located in coelomic, subcutaneous, and parenchymatous sites.
  • Fatty infiltration of organs may occur.
  • Lack of exercise, especially that necessary for food procurement, is a likely factor in obese patients.
  • Hormonal imbalances (rare).
  • Chronic obesity will lead to insulin resistance and predispose the animal to development of diabetes mellitus.

Predisposing factors

General

  • Inappropriate or excessive food provision.
  • Sedentary nature, ie species-specific.
  • Insufficient environmental enrichment to stimulate activity.
  • Insufficient physical space for active movement.

Specific

  • Feeding prey items or feed with increased fat content.
  • Female reptiles undergoing seasonal cycles of lipogenesis in preparation for folliculogenesis that do not have the opportunity to breed.
  • Housed in cages with reduced exercise facilities.
  • Steroid treatment for insulinoma and lymphoma can lead to weight gain.
  • Some reptile species have strategies to sit and wait for food, eg pythons, so have small energy expenditure in natural conditions; they eat less frequently.

Pathophysiology

  • Obese reptiles store fat in deposits located in coelomic, subcutaneous, and parenchymatous sites. Fatty infiltration of organs may occur. This contributes to poor mobility which can lead to conditions such as osteoarthritis, pododermatitis.
  • Lack of exercise, especially that necessary for food procurement, is a likely factor in obese patients, along with overfeeding or feeding a diet too high in fat.
  • Obesity is likely to negatively affect quality of life with impairment of movement (and potentially thermoregulation) and stress to, eg the cardiovascular and musculoskeletal systems. Obesity can be a factor in dystocia. Fat deposits may also act as space-occupying masses.
  • Obesity may contribute to shorter lifespans.
  • Obesity may also predispose to hepatic lipidosis Hepatic lipidosis: a pathological increase in accumulation of triglycerides in hepatocytes which negatively affects hepatic function.
  • Species prone to stress-induced anorexia seem to be especially vulnerable to hepatic lipidosis.
  • Obesity can cause or exacerbate heart disease:
    • Excessive fat affects the heart as cholesterol is laid down in blood vessels, including the coronary vessels.
    • High blood pressure can also lead to cardiac disease.

Timecourse

  • Variable; usually prolonged over weeks to months.

Epidemiology

  • Usually affects individuals, although dietary and husbandry errors may lead to group susceptibility in collections.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Mans C & Braun J (2014) Update on common nutritional disorders of captive reptiles. Vet Clin Exotic Anim Pract 17 (3), 369-395 PubMed.
  • Divers S J & Cooper J E (2000) Reptile hepatic lipidosis. Semin Avian Exotic Pet Med (3), 153-164 JExoticPetMed.

Other sources of information

  • Heard D (2019) Crocodilians. In: BSAVA Manual of Reptiles. 3rd edn. Ed: Girling S & Raiti P. BSAVA, UK. pp 447.
  • Raftery A (2019) Clinical Examination. In: BSAVA Manual of Reptiles. 3rd edn. Ed: Girling S & Raiti P. BSAVA, UK. pp 95.
  • Rendle M (2019) Nutrition. In: BSAVA Manual of Reptiles. 3rd edn. Eds: Girling S & Raiti P. BSAVA, UK. pp 49-69.
  • Kischinovsky M, Raftery A & Sawmy S (2018) Husbandry and Nutrition. In: Reptile Medicine and Surgery in Clinical Practice. Eds: Doneley R, Monks D, Johnson R & Carmel B. Wiley-Blackwell, UK. pp 45-60.
  • Donoghue S (2006) Nutrition. In: Reptile Medicine and Surgery. 2nd edn. Ed: Mader D R. Elsevier, USA. pp 251-298.
  • Calvert I (2004) Nutrition. In: BSAVA Manual of Reptiles. 2nd edn. Eds: Girling S J & Raiti P. BSAVA, UK. pp 18-39.
  • McArthur S & Barrows M (2004) Nutrition. In: Medicine and Surgery of Tortoises and Turtles. Eds: McArthur S, Wilkinson R & Meyer J. Blackwell Publishing, UK. pp 82-83.
  • McArthur S (2004) Problem Solving Approach to Common Diseases of Terrestrial and Semi-Aquatic Chelonians - Hepatic Lipidosis. In: Medicine and Surgery of Tortoises and Turtles. Eds: McArthur S, Wilkinson R & Meyer J. Blackwell Publishing, UK. pp 333-335.
  • Divers S J (1999) Reptilian Liver and Gastrointestinal Testing. In: Laboratory Medicine, Avian and Exotic Pets. Ed: Fudge A M. Saunders, USA. pp 205-209.

Organisation(s)

  • British Small Animal Veterinary Association (BSAVA) Obesity Position Statement. Website: www.bsava.com.