Avian Exotics

What questions are asked when feeding captive birds?

1. What is consumed by the bird?

2. Are supplements provided?

3. How is food presented?

4. What is offered and how often (daily/weekly)?

5. Does the bird have a favorite food?

What are the required percentages of water, protein, lipid content, and calcium for psittacines?

• Water- 2.4%

• Protein- 10-15%

• Lipid- 4-5%

• Calcium- 0.5%

What is the recommended diet for passerines (granivorous)?

• 50% ½ seed and ½ pellets

• 50% vegetables> fruits

• Dried insects as treats

• Carotenoids for feather colour

State the drinking mechanism, recommended diet, and which type of columbiformes (granivores) require higher nutrient content?

• Drink via suction

• Commercial avian crumble or pellets, Seed and legumes, small quantity of diced vegetables and insects

• High requirement for racing pigeons or laying females

What parameters are used to assess nutritional status of exotic birds?

• Weight

• BCS; keel and pectoral muscle mass

• Skin and subcutaneous tissue for fat deposit

• Feather quality and colour, presence of stress bars on feather shaft

List the diet for companion birds

• Seed based mixes

• Formulated diets

• Pulse mixes

• Fresh produce

What issues are associated with traditional seed based mixes?

• >20% High fat content (Obesity, Atherosclerosis, Hepatic lipidosis, lipomas)

• Chronic malnutrition 

• Fungal contamination possible (mycotoxins)

• Inappropriate Ca/P, iron, copper, manganese, iodine (Hypocalcemia, Iodine deficiency) 

• Low vitamin A, C, D3, B (Hypovitaminosis A)

• Low protein and amino acids (Plumage colour abnormalities, dry skin/hyperketatosis)

What are some disadvantages of formulated diet?

• Cost, difficulties with transitioning, lack of variety, decreased forage opportunities

What are the constituents for pulse mixes?

• Mix of beans (mung, soy, black-eye, chickpeas) soaked for 24hrs to allow sprouting.

What advantages and disadvantages of pulse mixes?

• Pros: Increase digestibility

• Cons: High carbs, low calcium, Increase change of microbial contamination

What is a recommended diet for psittacines?

• 75% formulated pellets

• 15-25% produce; more veggies than fruits

• <5% healthy human food

• 1-2 nuts per day as treats

Possible recommendations converting to pellet diets

• Gradual transition: 20-25% increments over 1-2 weeks at a time

• Try various shapes, sizes, and colour pellets

• Monitor weight and fecal output throughout

How often is molting and what can occur in malnourished birds?

Once a year
malnutrition → dull friable feathers → feather destructive behavior

What are the contributing factors to obesity in companion birds?

• Reduced energy requirement in captivity

• Selective feeding and inappropriate diet

What species of birds are commonly affected by obesity?

• Budgies, cockatiels, cockatoos, amazon, african grey

What are some clinical signs associated with hypovitaminosis A in birds?

• Squamous cell metaplasia

• Blunted choanal papillae

• Oral plaque

• Pododermatitis

• Uropygial gland impaction

• Renal failure, air sac hyperinflation, recurrent URI

What are some physical signs of vitamin A deficiency?

• Dry and flaky skin

• Beaks and toenails grow rapidly but deformed

• Abnormal feather colouration; amazon parrot

• Brittle and friable feathers

Sources of vitamin A for birds

Spinach, Cod liver oil (2-3 times a week), pumpkin, mango, egg yolk

What clinical signs are seen in calcium deficient birds?

• Reproductive disease

• Seizures, tetany, cardiac arrhythmias

• Impaired bone development

Which species of bird are susceptible to hypocalcemia?

• African grey with hypocalcemic seizures

• Cockatiels and lovebirds with egg binding

State the three causes of Ca deficiency

• Too little Ca

• Too little active Vitamin D

• Too much P

Calcium metabolism is regulated by?

Vitamin D, parathyroid hormone, calcitonin

What are some clinical signs of nutritional secondary hyperparathyroidism?

Juvenile osteodystrophy, seizures, fractures, poor reproductive performances

What is the predisposing factor for hepatic lipidosis?

Diets high in saturated fats

State the diagnosis for hepatic lipidosis

• Coelomic palpation, imaging

• Serum liver enzymes, bile acids

• Liver biopsy

What are the possible treatments for hepatic lipidosis?

Hepatoprotectives (milk thistle)

Diet changes

Supportive care

State the condition, species affected, lesions, diagnosis and treatment

1. Lipoma; benign proliferation of lipocytes

2. Budgies

3. Subcutis of the sternum and abdomen

4. FNA and cytology

5. Correct diet and exercise, iodine supplements to increase metabolism of fatty tissues, surgical removal

What are some risk factors associated with atherosclerosis in birds?

• High energy, high fat diet

• Dyslipidemia

• Species predilection 

• Female >30 yrs

• Low physical activity

What are some clinical signs associated with atherosclerosis?

• Cardiac dysfunction, hypertension

State the condition, species affected, clinical signs, diagnosis, treatment/therapy

1. Iodine deficiency (goiter)

2. Budgies on all seed diet

3. Cervical swelling, voice changes, dyspnea, regurgitation

4. History, physical examination

5. Oral iodine supplementation, lugol’s iodine in water, pink iodine blocks

Scales on the plantar surface of feet indicate?

Biotin deficiency

What are associated with stress bars?

• Methionine and Hypovitaminosis D deficiency

Feather pecking is due to a deficiency in?

Sulphur containing amino acids; methionine and cysteine 

What can cause splayed legs?

• Excess Vitamin A and E

• Cu and Manganese deficiency 

Seizures, ascending paralysis and opisthotonos are caused by?

Thiamine deficiency

Pododermatitis and bumblefoot are caused by?

• Hypovitamin A

• Biotin 

• Excess fat

What parameters are evaluated in bird feces?

• Colour

• Volume

• Consistency 

• Undigested food

What diagnostic tests are done in feces (fresh sample)?

• Fecal float

• Direct wet mount

• Gram stain

• Acid fast stain

• Culture and sensitivity 

• EM

• PCR for enteric viruses

What diagnostic tests are done in the oral cavity or crop?

• Direct wet mount

• Gram stain

• Cytology

• Culture and sensitivity

• PCR

What are the predisposing factors for sour crop/ crop stasis?

• Food fed at the wrong temperature or consistency

• Not allowing the crop to empty between feedings

• Poor hygiene

• Incorrect incubation temperature

• Humidity

• Concurrent disease

What diseases cause plaques in the UGIT?

• Poxvirus

• Trichomoniasis

• Vitamin A deficiency

• Candidiasis

• Capillariasis

• Bacterial stomatitis

• Mucosal papillomatosis

• Neoplasia

Candidiasis is common in?

Young immunosuppressed lorikeets on antibiotics and high on sugar nectar

What lesions are common with candidiasis?

White oral plaque with caseous exudate

What are the species affected, organs involved, and etiological agent of trichomoniasis?

• Pigeons, raptors, budgies 

• White caseous plaque in oral cavity, crop, esophagus, proventriculus

• Trichomonas gallinae

Avian gastric yeast is caused by and state the characteristics

Macrorhabdus ornithogaster

Large cigar shaped

What are the organs affected and clinical signs of avian gastric yeast?

• Proliferate at proventriculus isthmus and ventriculus

• Chronic weight loss (going light)

• Apathy

• Whole seed fecal passage 

Macrorhabdus ornithogaster affects which species of birds?

• Psittacines (canary, toucan, zebra finch)

• Passerines (budgies)

• Columbiformes (pigeons)

• Galliformes (broiler, turkey)

What are used to treat Macrorhabdus ornithogaster?

• Oral amphotericin B for 10 days

• Fluconazole

What bacteria cause enteritis and septicemia in psittacines?

Enterococcus hirae

What cause yellowish diarrhea and enteritis in psittacines, passerines and waterfowl?

Campylobacter jejuni

What does Clostridium perfringens cause in psittacines and ostriches? 

Necrotic enteritis and foul smelling feces

Clostridium tertium cause what in cockatoos?

Megacolon and foul diarrhea

Clostridium species can cause

Lymphoplasmacytic inflammatory reaction in colon

What can be used to treat Clostridium?

Metronidazole and Clindamycin

What can be used to treat Isospora canaria and serini?

• Trimethoprim sulfa drugs

• Amprolium

• Toltrazuril

Why is liver disease hard to detect early in birds?

• A large percentage of liver tissue must be affected before clinical signs appear.

• Birds on poor diets often already have reduced hepatic functional mass.

• The liver’s ability to regenerate can mask early disease.

What history factors increase suspicion of hepatic disease in birds?

• Dietary issues (poor diet, high fat, low protein)

• Toxins (e.g., aflatoxins)

• Medications or supplements

• New animals (infectious risk)

• Obesity

• Duration & severity of illness

Key clinical signs of liver disease in birds

• Anorexia

• Lethargy

• Weight loss or obesity

• Coelomic distension ± ascites

• Dyspnea (enlarged liver compresses air sacs)

• Integumentary changes:
  • Overgrown beak/nails
  • Poor feather quality
  • Darkened feather pigment

• GI signs: PU, diarrhea, regurgitation

• Neurologic signs (hepatic encephalopathy)

Why is icterus not seen in birds with liver disease?

Birds excrete biliverdin, not bilirubin.
Thus green/yellow urates or feces occur instead of jaundice.
Biliverdinuria can occur with hepatic disease OR hemolysis.

What causes abnormal bleeding in birds with liver disease?

Liver dysfunction → coagulopathies, leading to:

• Bruising

• Melena or fresh blood in droppings

Physical exam findings of avian hepatic disease

• Hepatomegaly, especially on the right side

• Coelomic distension ± fluid wave (ascites)

• Dyspnea due to mass effect

• Poor feathers, abnormal keratin growth

• Weakness, depression

Diagnostic tests for avian liver disease

• CBC: anemia, inflammation

• Biochemistry: AST, cholesterol, bile acids, lipids, proteins

• Radiographs: hepatomegaly, coelomic fluid

• Ultrasound-guided FNA

• Coelomic fluid analysis

• Liver biopsy: gold standard

• Coelioscopy: direct visualization + sample

Medical management — general support for liver disease

• Fluid therapy

• Maintain POTZ (temperature)

• Oxygen supplementation if needed

• Correct negative energy balance

• Gavage feeding or tube feeding if necessary

Dietary management for hepatic disease in birds

• High-quality, easily digestible proteins & fats

• Low carbohydrates

• High fiber

• Ensure adequate caloric intake

• Reverse catabolic state

Supplements used in avian liver disease

• Vitamins B, E, K

• Essential amino acids

• Essential fatty acids

• SAMe (S-adenosyl-methionine):
  • Methionine/carnitine precursor
  • Anti-oxidative, stabilizes hepatocyte membranes

• Silymarin (milk thistle): antioxidant

• Denamarin® = SAMe + Silybin

Species most affected by iron storage disease

• Toucans

• Toucanettes

• Aracari

• Mynah birds

• Birds of paradise
  (Not all softbills are affected.)

Organs commonly affected in iron storage disease

• Liver

• Spleen

• Heart

Excess iron accumulates as hemosiderin in hepatocytes + macrophages.

Causes of iron storage disease

Multifactorial:

• Dietary excess

• Genetic predisposition

• Environmental factors
  Often a combination.

Histological appearance of iron storage disease

• Hepatocytes and macrophages heavily loaded with brown pigment

• Pigment stains positive with Prussian Blue (iron-specific stain)

Clinical signs of iron storage disease

• Lethargy

• Anorexia

• Ascites

• Biliverdinuria

• Severe hepatic enlargement or cirrhosis

Diagnostics for iron storage disease

• Signalment + signs

• CBC (often high Hct: 60–80%)

• Biochemistry (↑ AST, ↑ bile acids)

• Radiographs or ultrasound

• Endoscopy

• Liver biopsy with Prussian blue staining (definitive)
  Serum iron + TIBC not useful.

Treatment of iron storage disease

• Phlebotomy

  • Remove ~1% body weight

  • Often every 2 weeks lifelong

• Chelators:

  • Deferoxamine (SC/IM) — limited success

  • Deferipirone PO 50 mg/kg q8h — effective in poultry/pigeons

• Diet:

  • <80 ppm iron

  • Avoid citrus or foods increasing iron absorption

  • Provide tannins (e.g., tea)

Causes of bacterial hepatitis in birds and exotics

Usually secondary to:

• Sepsis, or

• Spread via enterohepatic circulation

Common organisms:

• Gram negatives

• Mycobacterium avium

• Chlamydia psittaci (birds)

• C. pneumoniae (reptiles)

Diagnostics for bacterial hepatitis

• FNA or liver biopsy

• Cytology & histopathology

• PCR

• Culture

• Blood cultures if septicemia suspected

Species commonly affected by hepatic lipidosis

Birds:

• Amazon parrots

• Cockatoos

• Budgerigars

• Lorikeets
  Reptiles:

• Savannah monitors

• Bearded dragons

• Chameleons

• Monitors
  All reptiles: during hibernation, vitellogenesis, illness.

Causes of hepatic lipidosis

• High-fat, low-protein diet

• Sedentary lifestyle

• Nutrient deficiencies (EFAs, sulfur AAs, vit B & E)

• Low carnitine

• Hereditary factors

• Negative energy balance from comorbidities

Clinical signs of hepatic lipidosis

• Severe depression

• Weakness, flaccid musculature

• Regurgitation, diarrhea

• Hepatomegaly

• Distended coelom

• Biliverdinuria

• Poor body condition

Diagnostics for hepatic lipidosis

• CBC: anemia, inflammation

• Biochemistry: lipemia, ↑ AST, ↑ bile acids, abnormal proteins, ↑ uric acid

• Imaging: radiographs, ultrasound, endoscopy

• FNA or biopsy (definitive)

• Histopathology

Treatment of hepatic lipidosis

• Reverse negative energy balance

• High-quality digestible protein

• Fluid therapy

• SAMe

• Vitamins B & E

• Long-term nutritional correction

What is the purpose of nebulization therapy?

To deliver medications directly to diseased tissues and hydrate airways to improve clearance of exudate and debris.

Common toxins affecting birds?

• PTFE fumes (overheated non-stick cookware)

• Cigarette smoke

• Air fresheners, candles

• Wildfire smoke

• Vitamin A deficiency

What species are affected by avian chlamydiosis (zoonotic)?

Psittacines, turkeys, ducks, pigeons, cage birds, wild birds.

Which genotype of Chlamydia psittaci affects psittacines? 

Genotype A

Transmission route for Avian chlamydiosis/ parrot fever?

Horizontal: primarily inhalation of chlamydia in feces and ingestion

Diagnostic methods for parrot fever?

• Cytology showing intracytoplasmic inclusions (Giemsa/PVK stains)

• PCR (cloacal + orochoanal swabs)

• Culture (yolk sac inoculation)

• IHC

• Indirect immunofluorescence (but false positives possible)

What is used to treat parrot fever?

Doxycycline or azithromycin (intracellular penetration required).

What is used to treat aspergillosis?

Voriconazole

What are tracheal/ air sac mites?

Sternostoma tracheacolum

Which birds are most affected by air sac mites?

Finches and canaries

Clinical signs of air sac mites?

Clicking, wheezing, gasping, coughing, neck stretching.

What is the diagnostic test for tracheal mites?

Tracheal transillumination (wet the feathers).

Transmission route for poxviruses?

• Mosquito vectors

• Skin trauma

• AI in turkeys

• Aerosolized scabs

• Cannibalism

What are the clinical forms of poxviruses?

• Dry pox: scabs on comb, wattle, eyelids.

• Wet pox: diphtheritic yellow plaques in mouth, esophagus, trachea → respiratory distress.

What are the histological hallmarks of poxviruses in exotics?

Bollinger bodies — eosinophilic intracytoplasmic inclusion bodies.

What are some characteristics of the bird brain?

• Lissencephalic — smooth-surfaced; no cortical folding.

• Cortical cells located within the cortex but not on the surface of the telencephalic complex.

• Lack a neocortex; their cerebral cortex is relatively underdeveloped.

What is the corpus striatum responsible for in birds?

Association center — involved in learning, behavior, motor control.

Which non-parrot species have high neuron counts?

Corvids (songbirds): Raven, Rook, Jackdaw, Magpie.