Herp Nutrition Flashcards

Question

What is the relationship between UV light and vitamin D? What wavelengths are necessary?

Answer 1

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

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

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

Answer 6

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

Answer 7

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

Answer 8

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

Answer 9

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

Answer 10

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

Answer 11

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

Answer 12

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

Answer 13

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

Answer 14

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

Answer 15

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

Answer 16

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

Answer 17

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

Answer 18

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

Answer 19

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

Answer 20

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

Answer 21

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

Answer 22

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