Herp Nutrition Flashcards
Which macronutrient drives reptilian growth?
Protein
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Which reptilian species can and cannot synthesize Vitamin A?
All herbivores appear capable of synthesizing vitamin A
Insectivores & carnivores have poor conversion of beta-carotene (which is what is in a lot of supplements) and need retinyl palmitate from animal sources.
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Proper ratio of Vitamins A: D: E for herp species
100: 10: 1
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What herp species cannot utilize vitamin D?
What form of vitamin D is needed in reptilian supplements?
Iguana & Cyclura spp.
Vitamin D2 (cholecalciferol)
Reptiles can’t convert vitamin D2 (ergocalciferol)
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Which forms of calcium are best absorbed by herp species?
Calcium carbonate - 40%
Calcium citrate - 21%
Calcium lactate - 13%
Calcium gluconate - 9.3%
Calcium glubionate - 6.6%
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Generally, insects are lacking which nutrients?
Poor calcium:phosphorus ratios, no carbohydrates (silkworms excepted)
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Whiich invertebrates are high in fat?
Larval insects have high fat content – mealworms, waxworms, butterworms
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Which invertebrates have better Calcium Phosphorus Ratios?
Cocooning eastern tent moths, stone flies, black soldier flies
Crustaceans – crabs, shrimp, isopods, woodlice
Earthworms, night crawlers
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Which invertebrates are not vitamin A deficient?
False katydids, migratory locusts, termites, silkworms
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the proper composition of an insect gut loading diet?
>8% DM Calcium - >12% kills some inverts
Soaked cotton ball or damp paper towl for water
Dust with calcium supplement (multi-vitamins don’t have enough Ca)
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the benefit of feeding a diversity of insects?
Less deficiencies, better growth
Crickets, waxworms, mealworms, superworms, Dubia roaches often make up the bulk of the diet
Should be supplemented with silkworms, black soldier fly larvae (Phoenix worms), tobacco or tomato horn worms, bean beetles, fruit flies, springtail, and wood lice as well as wild-caught, seasonally available insects such as moths, cicadas, flies, grasshoppers, bees (remove stingers), cockroaches, and crustaceans
Pesticide toxicity from wild insects is rarely an issue
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Genus and toxic agent of the firefly
Photinus - lucibufagin toxicity (cardiotoxin)
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the proper way to thaw vertebrate prey and why?
Thaw and warm completely right before feeding.
Slowly thawing over several hours allows gut bacteria to bloom
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the specific dynamic action of pythons?
Snakes metabolic rate rises dramatically while beginning to digest
Python selectively digest protein first – amino acids provide immediate needs for SDA
Lipids are digested later
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
How do you get hatchling snakes to take thawed prey?
Leave pinkie in cage overnight
Wash pinkie to remove rodent scent – scent with preferred natural prey – lizards, fish
Braining is an optimal stimulus for feeding response
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Issues with feeding fish?
Thiaminases – fish need supplementation of thiamine 25-30 mg/kg of wet fish
- Trout and most freshwater fish do not have thiaminases
Vitamin E – oxidation of fish lipids depletes vitamin E
- Supplement 100 IU of vitamin E/kg of wet fish
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What are the differences between hatchling and adult crocodilian diets?
Hatchlings
- Wild diet - Insects, spiders, crustaceans, fish & amphibians
- Metabolic rates 25 times that of adult
- In captivity – feed gut loaded insects, rodents, and whole fish or shrimp
- Feed 2-3 times per week (about 3-4% of BW/week in wild)
Adults & subadults
- Larger prey items – crustaceans, fish, rodents, rabbits, chickens, pigs, nutria, sheep
- Subadults fed 1-2 times/week, adults once a week to once every other week (0.5 – 1% BW/week)
Issues - lead shot, thiamine/vitamin E for fish eating species
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Which groups of reptiles require UV light?
All herbivores
Iguana & rock iguanas are especially bad at using vitamin D
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the proper composition of an herbivorous reptile diet?
Wild diets
- Wild tortoises mainly eat grasses or woody plants
- Wild iguanas only eat younger leaves with higher protein contents (>25% DM)
- Wide variety of species eaten – even backyard exhibits cannot replicate that
Simulating those diets in the wild
- Greens, vegetables, and fruits will be unlikely to replicate
- Most grasses & hays meet requirements, some low in Ca
- Clover & alfalfa higher in Ca & Protein
Commercial diets appear better than greens, fruits, or vegetables
Switching over to commercial diets
- Less frequently
- Hay should be good quality, cut short, and misted or briefly soaked
- Greens can be mixed in with hay
- Pellets can be mixed with greens as well
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Which plants are too high in oxalates for proper herp diets?
Spinach, beet greens, sorrels, purslane – oxalate: Ca ratios >2
- Oxalates bind Ca reducing the absorbable Ca
- Not good sources of calcium as they would appear
Prickly pear, collards, chard, dandelions, kale, turnip greens, brussel sprouts, parsley
- Oxlate: Ca ratios less than 2 – good sources of calcium
Ruminants & humans have a bacteria – Oxalobacter formigenes – that metabolizes oxalic acid – reptiles may have this as well
Oxalates in diet do not lead to Ca oxalate stones – urate stones are the most common
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What plants are toxic to reptiles?
Rarely an issue in tortoises – they eat several species of toxic plants
Exceptions
- rhododendrons (Rhododendron spp., grayanotoxins cause flaccid paresis)
- oleanders (Nerium oleander)
- chinaberry trees (Melia azedarach)
- tree tobacco (Nicotiana glauca)
- toadstools (Agaricomycetes)
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the preferred diet of the 7 species of sea turtle?
In captivity, all can be maintained on a carnivorous diet (fish & shellfish)
- Leatherbacks – gelatinovores – jellyfish, tunicates, sea squirts
- Hawksbills – sponges, corals, tunicates, shrimp, squid
- Ridleys – crab fish, jellyfish, shrimp, molluscs, Olive ridleys also eat algae (omnivores)
- Loggerheads – crabs (horseshoes especially) and mollusks
- Flatbacks – omnivores (fish, crabs, molluscs, algae)
Greens – carnivorous juveniles, sea grasses as adults (especially turtle grass) as well as algae, jellyfish, mollusk eggs and sponges
- feed them calcium rich greens
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the proper nutrition for a debilitated sea turtle?
Start with rehydration & correcting electrolyte imbalances
Tube feeding – stressful, regurgitation common – start with 0.5% BW increase to 3%, tilt animal backwards after feeding
Transition to softer foods (fish fillets, debeaked squid) before whole prey
Parenteral nutrition has also been used
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What biotransformations does Vitamin D undergo?
Which enzymes are critical to this process?
Reptiles require Vitamin D3 (cholecalciferol)
- Either from diet or UVB photochemical production
Hydroxylation in liver produces calcidiol or 25-hydroxyvitamin D
Calcidiol is converted to calcitriol or 1,25-dihydroxyvitamin D in the proximal renal tubules – this is the active form
- This conversion is catalyzed by 1 alpha-hydro which is increased by PTH due to low levels of Ca or increased P
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the relationship between UV light and vitamin D?
What wavelengths are necessary?
Between 280-320 nm – peak vitamin D synthesis between 295-297 nm in mammals
Reptiles that don’t require it
- Snakes – some snakes still have higher calcidiol levels with it (corn snakes over BP) – other snakes do better with it (diamond pythonds, indigo snakes, green snakes)
- Nocturnal geckos - one study suggested they may still rely on photobiosynthesis but are just better at it
UVB supplementation in BEDR alone produced 18 time the calicidiol and 5 times the calcitriol than in BEDR supplemented
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What is the mechanism behind nutritional secondary hyperparathyroidism?
When ionized Ca drops, PTH is released
- Increases Ca resorption from bone, reabsorption from kidneys, absorption from intestines
- Eventually can lead to weakened bones, pathologic fractures, fibrous osteodystrophy & shell softening
- If ionized calcium drops too low – seizures, tetany, and flaccid paralysis
When ionized Ca is high, ultimobranchial bodies produce calcitonin
- Inhibits osteoclasts, reduced tubular reabsorption, negative feedback to reduce PTH secretion
NSHP is usually due to excessive secretion of PTH in response to hypocalcemia
- Secondary to low Ca or Vitamin D3 or excessive P (poor Ca: P ratios)
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What are the clinical signs of metabolic bone disease in herpetological species?
Lethargy, weakness, anorexia, decreased appetite, lack of growth, sprawl, inability to raise body during ambulation, pathologic fracutres, paresis, paralysis, flattened ribs, bowed longbones, pliable jaws
Iguanas – bloat, osteodystrophy
Chameleons – weakened grip, bowed or fractured long bones, scoliosis of parietalal crest, tail weakness
Tortoises – soft or deformed shells, inability to lift shell when walking, splayed legs, decreased appetite
- Neonate shell pliability disappears between 6-18 months
- Chelonians don’t develop osteodystrophy, they just poorly calcify the shell
- Tortoises that aren’t eating carry a poor prognosis
- Plastron can also be flexible
- Medial nails are excessively worn, lateral nails are overgrown due to walking on heels
Box turtles – marginal cutes curl dorsally, rhamphotheca may curve more like a parrots beak, cloacal/phallic prolapses more common
Crocodilians – weak, sluggish, ataxic, upper jaw can bend upwards, scoliosis etc, teeth may be translucent or diaphanous (glassy) or fall out
Amphibians – abnormal posture & locomotion, anasarca, vertebral or mandibular deformity, fractures, no calcium in endo-lymphatic sacs
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
How do you diagnose NSHP in reptiles?
40-50% of bone mineralization must be lost before it is visualized radiographically
Total and ionized Ca tends to be within normal limits
Mammalian PTH assays do not appear to be accurate – this would be definitive if it worked
Calcidiol values are more easily assessed
Best way to measure bone density is with CT or dual-energy x-ray absorptiometry
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
How do you treat NSHP in reptiles?
Patients with tetany should receive 100 mg/kg Ca gluconate slowly IV or IM q6h until tetany resolves
Orally
- Easiest with calcium rich syrups – but these have the lowest availability
- Ca glubionate – 21 mg/mL elemental calcium
- Ca gluconate is 24 mg/mL elemental calcium
- Crushing a tums tablet will provide the granular calcium which is most effective – can still be syringe or tube fed if combined with water
UVB supplementation
Calcitonin
- Salmon calcitonin – 50 IU/kg IM – repeat in 1 week if normocalcemic or 1 week after starting Ca supplementation
- Also thought to have an analgesic effect on skeletal pain
- Some studies showed rapid increases in Ca, others showed little change – more studies needed
- Do not give if patient is hypocalcemic
Fractures – External coaptation
Spinal trauma - treatment takes months – revaluate at 1, 2, 4, and 8 weeks until weight is improving and patient is recovering
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What prognostic indicators exist for NSHP in herps?
Multiple deficiencies are harder to recover from (vitamin A)
Lizards and crocodilians respond better than chelonians
Chronic worse than acute
Several months of daily treatment is needed (investment on owner’s part)
Decreasing radiopacity & hypocalcemia worsen prognosis
Anorexic, pathologically soft-shelled chelonians – poor prognosis – typically die
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What are the various forms of Vitamin A?
Retinol – alcohol form
Retinal – aldehyde form
- Combines with opsin to form rhodopsin – light-absorbing molecule for vision
Retinoic acid – acid group
- Hormone like growth factor for epithelial cell differentiation
- Deficiency results in hyperkeratosis (thickening of stratum corneum with excess keratin) and squamous metaplasia (transformation of specialized epithelium into keratinizing stratified squamous epithelium)
- Affects respiratory, ocular, endocrine, GI, & genitourinary systems
Precursors
- Beta carotenes & other carotenoids from plants
- Herbivores and omnivores are apparently good at converting carotenoids into retinol
- Cane toads and tomato frogs cannot convert beta carotene to retinol
- Tomato frogs can use other carotenoids but not beta carotene
- Retinyl palmitate from animals
- Converted to retinol in small intestine
- 80-90% of vitamin A is stored in the liver in this form
Multivitamin supplements
- About a third use beta-carotene instead of retinyl acetate or retinyl palmitate
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What are the clinical signs of Vitamin A deficiency?
Short tongue syndrome in amphibians
- Replacement of mucus producing epithelium with squamous metaplasia makes tongue less sticky
- Recognized in bufonids, dendrobatids, hylids (tree frogs), ranids (true frogs), and rhacophorids (foam nesting frogs)
- VAD also produces changes in skin, conjunctiva, GI, genitourinary tracts leading to poor reproductive success, reduced tadpole survival, & immune dysfunction
Reptile VAD
- Ocular Changes
- Keratin builds up in lacrimal, salivary, & mucous grands - squamous metaplasia
- Decreased conjunctival goblet cells & lacrimal production produced dry eye
- Emydid turtles & leopard geckos – lacrimal glands block & swell closing the palpebral fissure
- LG also have periocular glands that fill with solid debris and decreased tear production resulting in keratitis, corneal ulceration, & scarring/blindness
- Chameleons – blepharospasm, thick mucus, thickened palpebral margins, poor aim & prehension (similar to STS)
- Systemic changes
- Insectivorous lizards – difficulty catching prey, recurrent hemipenal plugs, dysecdysis, dull coloration (chameleons), stomatitis (leopard geckos)
- Crocodilians – brown dorsal lingual nodules, renal & visceral gout due to renal tubular squamous metaplasia
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
How do you diagnose hypovitaminosis A?
Mostly clinical signs & history
Difficulty – multiple forms measured, vitamin A degrades with light, high temps, & autolysis
Plasma VA concentrations do not represent whole body status
Liver levels are best indication of whole status – biopsy or post-mortem examination
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
How do you treat hypovitaminosis A in herps?
Reptiles
- 0.1 mL of Vitamin A (500,000 IU VA Palmitate/mL) and Vitamin D (100,000 IU/mL) SC
- Works for 50 g to 1 kg reptiles without toxicity
- Repeated in 2 weeks
- Oral A&D solution (100,000 IU VAP/mL & 10,000 IU VD/mL)
- Dosed at 66 IU/gram – repeated in 7 days
- Appears the parenteral drug is less toxic administered orally
- Remove cellular debris
Amphibians
- Smaller size requires diluted formulation
- Aquasol A – topical treatment 50 IU every other day worked better than dusting
- Can be diluted 1: 10
- Feeding a whole pinkie may help as well
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What are the clinical signs of hypervitaminosis A?
Signs – blisters or bullae from around neck and extremities – sloughing of epidermis by 14 days
- Separation of stratum corneum from stratum germinativum, subcorneal acantholysis (loss of desmosomes), intercellular edema, thickening of the skin
Documented in Hermann’s tortoises at 100,000-400,000 IU/kg IM water-soluble doses but not fat-soluble at same dose
- Water soluble vitamin A is resorbed more quickly and accumulates faster in liver – has higher potential for toxicity and should be avoided
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
How do you treat hypervitaminosis A in reptiles?
Preferred treatments
- Similar to full thickness burns – address hypovolemia & infection
- Clean site with gentle flushing – initially dilute chlorhexidine then sterile saline
- Silver dressings and hydrogels appear more effective than SSD which is typically used
- Vitamin E appears to prevent some of the side effects of hypervitaminosis A
- Taurine may also help as it conjugates retinoids allowing them to be excreted in bile
Prognosis & prevention
- Avoid use of injectable vitamin A in herbivores
- Widespread epidermal soughing is a guarded prognosis
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss hepatic lipidosis in reptiles
Squamates use coelomic fat for storage, chelonians tend to use hepatic storage (or the prefemoral fossa)
Normal fat stores used for hibernation, estivation, or fasting
- Those mechanisms become disrupted in hepatic lipidosis
Shortage of dietary glucose or free fatty acids causes hormonal changes and sympathetic activity resulting in decreased insulin release
- This promotes peripheral lipolysis and release of free fatty acids which get taken up in liver
- Protein shortage or deficiencies in certain amino acids (methionine, arginine, carnitine) prevent the formation of very low-density lipoprotein so triglycerides accumulate in the liver
Clinical signs
- Sudden onset lethargy and anorexia
- History of large amounts of fruit or fatty larvae
- Advanced cases – flaccid, edematous, weak, anemic, hypoabluminemic, hypocalcemic, hepatic encephalopathy, hypercholesterolemia, hypertriglyceridemia
- Enlarged liver – lateral liver silhouette in lizards should be less than half the dorsoventral coelomic space
Diagnosis
- Triglycerides are often higher but not always liver enzymes
- Biopsy is definitive – pale, swollen edges, ooze grease on cut surface, float in formalin
Treatment – long term nutritional support for chelonians until eating on own (weeks to months)
- Smaller more frequent feedings are better than larger less frequent feedings
- Carnivore critical care diets tend to be too high in fat
Prognosis & Prevention
- Guarded for patients still eating, guarded to poor for those not eating
- Prevention is better – good diets are key
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss pyramidal shell growth in chelonians
Greater pyramiding in sulcatas with drier conditions – higher protein had a minor impact
Nocturnal heat exposure also lead to increased PSG
Increased growth rates lead to more PSG
Higher bone density is seen in affected tortoises
Prevent with better nutrition, humid retreats for growing tortoises, and allowing a night-time temperature drop
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
What vitamin B deficiencies do reptiles get?
How are they diagnosed and treated?
Thiamine Deficiency
- Thiamine destroyed by thiaminases – not inactivated by freezing, only boiling or cooking
- Thiamine isn’t stored since its water soluble and deficiencies develop quickly resulting in necrotizing encephalopathy (no gross lesions)
- Clinical signs – listlessness, poor righting reflexes, crocodilians floating with jaws open, anorexia, poor striking response in snakes, tremors, seizures, dysphagia
- Tx – dietary supplement (25 mg/kg in fish for 3-7 days) or vitamin b injections (100 mg/kg IM)
Biotin Deficiency
- Results from feeding raw unfertilized eggs exclusively
- Raw eggs contain avidin which is a tetrameric biotin binding protein which is denatured by cooking
- Clinical signs include muscle tremors and generalized weakness
- Egg-eating species – helodermatids, varanids, teids, Dasypeltis snakes
- Treat with multi-B injection
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss the effects of vitamin E & selenium deficiency in reptiles including any effects on wild populations
Steatitis, fat inflammation – yellow fat disease – occurs in carnivores fed diets high in polyunsaturated or rancid fat or low in tocopherols or selenium
Both vitamin E and selenium are antioxidants that protect against toxic effects of rancid fat
Saponified fats cause inflammation
Inadequate levels also cause muscles to degenerate
Widespread mortality of Nile crocodiles was noted in Kruger in 2005 possibly due to introduction of invasive silver carp high in polyunsaturated fatty acids
Clinical signs – large saponified fat deposits in tail render it unable to move, muscle degermation
Diagnosis typically on necropsy
No way to reverse saponification
Vitamin E (100 IU/kg fish or 1 IU/kg/day for reptile) and selenium supplementation prevents signs
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss reptilian geophagy
Free-ranging & captive tortoises, lizards, and crocodilian may consume stones, soil, or sand
- Mojave Desert tortoises eat calcium carbonate stones
- Crocodilians ingest them and they stay in stomach – either for ballast or grinding
60% of free-ranging desert tortoises have stones in GI tract
If reptile is not eating or defecating but a complete obstruction is not identified, aggressive rehydration, enemas, or stomach tubing with water or mineral oil may help
Don’t house reptiles on sand or gravel
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss the diagnosis and treatment of goiter in tortoises
Enlargement of thyroid gland to compensate for iodine deficiency
- Toxic goiter – enlargement with alteration in thyroid function
- Nontoxic goiter – not inflammatory or neoplastic or with alteration in thyroid function
Commonly misdiagnosed in giant tortoises – thymic hyperplasia
Dietary goiter very rare in reptiles
- Caused by brassica species in other animals
- Excess dietary nitrates from fertilized grasses & hay, hydroponic vegetables, & iodine intoxication – have also been noted to predispose animals to goiter
Potassium iodide 1 mg/kg PO daily reduced size of thyroid on ultrasound in a Greek tortoise
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss corneal lipidosis & xanthomatosis in herp species
Corneal arcus is a lipid storage disease in anurans
- Reported in hylid frogs – Cuban tree frogs, White’s tree frogs
- Females overrepresented
- Perilimbal white crystalline foci that become denser as they progress centrally
- Prognosis is poor for amphibian as many become blind and there is no treatment – lesions do not regress with better diet
Xanthomatosis is the deposition of cholesterol granulomas (more common in lizards)
- Folliculogenesis, hypercholesterolemia, nutrition, genetics or trauma may be involved
- Found in brain, viscera (liver), peripheral nerves, coelomic surfaces
- Prognosis is poor for lizards with neurological signs (brain) but coelomic xanthomas may be resectable
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss the various types and management of herp dehydration
Clinical signs more difficult to estimate in reptiles
- Limited skin turgor
- Dehydration greater than 8-10% still results in loss of moisture in retro-orbital fat pads causing sunken eyes
Types of dehydration
- Hypertonic – reptiles that aren’t drinking, are hibernating, have renal damage, or hyperthermia
- Isotonic – same amount of water and sodium is lost – hemorrhage, diarrhea, anorexia, vomiting
- Hypotonic – more sodium than water lost – prolonged anorexia & undernutrition
Maintenance fluid requirements range from 10-30 mL/kg/day
Rehydration – maintenance plus 25-33% of fluid deficit/day
- Rehydration rates of 3x maintenance or greater may cause fluid overload
Fluid types
- Warmed balanced – LRS, Norm-R, Plasmatlye-A commonly used
- D5W recommended in cases with profound water deficiency & hypernatremia
- Dextrose should generally not be given SC – 5% or less solutions have been used in human medicine
Administration – PO, SC, IV, IO – intracoelomic not recommended
- Shallow chin deep water will encourage drinking
- Enteral fluids at 5-10 mL/kg q8-24h via stomach tube may help with dehydration
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss the refeeding of a debilitate herp
Refeeding Syndrome
- During prolonged fasting (>4-5 days in cats, >2-5 days in humans, not known in reptiles) – body depletes intracellular K, Ca, P, Mg, and thiamine to maintain circulating levels
- Refeeding causes blood glucose to rise driving insulin release which drives glucose and K into cells which results in hypokalemia, hypophosphatemia, & hypomagnesemia
- These alterations lead to cellular dysfunction, cardiac arrhythmias/arrest, hemolysis, pulmonary edema, convulsions, & coma
Debilitated Reptile Care
- Start with rehydration and water-soluble vitamins for 2-5 days
- Limit nutritional intake to 10-25% of calculated requirements – increase slowly over several days
- Severe hypophosphatemia (> 30% drop from baseline) is an early indicator of refeeding
- Additional supplementation of K, P, and Mg may be indicated
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
Discuss the various ways to assist feed debilitated reptiles
Stomach volume - start at 5 mL/kg/feeding - may be able to go up to 10
Stomach Tubing
- Oral speculums – softer is better to avoid dental or mandibular trauma
- Catheter tip connection of red rubber tube, or vet wrapped 3 mL syringe cases
- Lizards - Insert speculum, guide lubricated pre-measured tube through the opening
- Snakes do not require speculums – keep head elevated, occlude the esophagus as you withdraw the tube, milking food material down to stomach may prevent regurgitation
- Chelonians – placing esophagostomy tube is preferable
Esophagostomy Tube
- Soft silicone tubes better tolerated than red rubber tubes – 14-24 Fr typically used
- Check with radiographs, flush tubes after each feeding, cap when not in use
- If regurgitation occurs, check tube placement, ensure adequate temperature, or reduce feedings
- Can unblock tubes with cola
Reference: Mader 2019, Chapters 27, 84, 122 - Nutrition, Nutritional Diseases, Nutritional Therapy
