Aflatoxicosis

Poultry aflatoxicosis

1. Avian mycotoxicoses
DrJenyK John

2. INTRODUCTION
•Mycotoxicosisis a disease caused by a toxic fungal metabolite known
as mycotoxin
•Fungal growth is required for mycotoxinproduction in grain
•Aflatoxicosis, ochratoxicosisand trichothecenemycotoxicosisare the
most commonly seen mycotoxicosisin poultry

3. Aflatoxicosis
•Most prevalent and economically the most important mycotoxinlikely
to be consumed by poultry
•Aflatoxinare highly toxic and carcinogenic mycotoxinsproduced by
A. flavus, A. parasiticusandPenicilliumpubertum
•Found in maize, ground nuts, cotton seed, millet, sorghum and other
feed grains
•Toxin is produced in warm (30ºC-35ºC) high humidity conditions-
common in tropics and subtropics
•Handling or storage of grains in these conditions anywhere would
stimulate aflatoxinproduction

4. Aflatoxicosis
•Aflatoxincontain aflatoxinsB1, B2, G1 and G2
•AflatoxinB1 usually in the highest concentration and is also the most
toxic
•Aflatoxinis stable once produced and is not destroyed during normal
milling and storage
•Young poultry are more sensitive to aflatoxinthan are adults
•Ducks being 10 times more sensitive than chickens and turkeys
intermediate between the two

5. Pathogenesis
•Afteringestion,aflatoxinB1undergobiotransformationintonumerous
highlyreactivemetabolites
•MetabolitesbindtoDNAandRNA,reduceproteinsynthesisand
decreasedcellmediatedimmunityandtoalesserextenthumoral
immunity
•Metabolicalterationsleadtoliver,kidneyandspleenenlargementand
bursal,thymicandtesticularatropy

6. Pathology
•Yellow discoloration of the liver, with multifocal hemorrhage
•Livers are enlarged, friable and develop white foci as lipid content
increases
Microscopic lesions
•Clear vacuoles in the cytoplasm of hepatocytes, karyomegalyand
prominent nucleoli, proliferation of bile ducts and fibrosis
•Extramedullaryhaematopoiesisin the liver which is in response to a
toxin induced anaemia

7. Pathology
•Produce immunosuppression and is associated with increased
susceptibility to infectious diseases and vaccination failure
•Toxic to B lymphocyte-cell mediated immunity are also decreased
•IS partly due to atropyof BOF, thymus and spleen
•Causes anemia-Young birds more susceptible
•Damages coagulation by interfering with several coagulation factors
mainly prothrombin
•Petechial hemorrhages are due to decreased clotting factor synthesis
and increased capillary fragility

8. Pathology
•In Leghorn chickens, aflatoxinblocks ova maturation and reduces feed
efficiency and egg production
•Hatchability is more sensitive than egg production
•Aflatoxinimpairs egg production
•Egg size, yolk weight and yolk as per cent of total egg size are
decreased
•Aflatoxinis rapidly excreted in the bile and urine and does not
accumulate or persist in body tissues-explain the rapid recovery of
egg production and hatchability after cessation of toxin ingestion

9. Pathology
•Aflatoxindecreases total serum protein, lipoprotein, cholesterol,
triglycerides, uric acid, calcium, P, iron, copper and zinc

10. Clinical signs
•Doesnotcause mortality directly although high levels (> 10.0 ppm)
may be lethal
•Decreased growth and poor feed conversion (> 1.0 ppm)
•Marked decrease in resistance to infections
•Failure of normal pigmentation and increased bruising (> 0.5 ppm)
•Decreased egg production and hatchability of eggs is reduced (>
2.0ppm)
•Breeder males testicular weights and sperm counts are reduced

11. Ochratoxicosis
•Less common but is more lethal
•Most toxic mycotoxinsof poultry
•Nephrotoxic metabolites are produced mainly by P veridicatumand A
ochraceouson different grains and feedstuffs
•Name ochratoxinis derived from A.ochraceus
•A,B,C and D
•OchratoxinA is the most common and most toxic
•Ochratoxinproducing fungus also produce citrinintoxic to poultry

12. •OchratoxinA occurs in maize, most small grains and in animal feeds
•It form readily in poultry feed under conditions of high temperature
and moisture
•OchratoxinA-main toxin
•Young chickens are most sensitive abdducks are 7 times more
sensitive to ochratoxinthan chicken
•Acute ochratoxicosisinduces mortality due to acute renal failure

13. Pathogenesis
•OchratoxinAinhibitsproteinsynthesis,produceacuteproximal
tubularepithelialnecrosisinthekidneysandinhibitsnormalrenaluric
acidexcretion

14. Pathology
GrosslesionsinacutelethalochratoxinAmycotoxicosis:palloroftheliver,
pancreasandkidneys
•Affectedkidneysarewhitetotan(yellowishbrown),swollen,hardandhave
whiteuratesdepositsintheureter
•Ifdamageisenoughtocauserenalfailurethenthereisdehydration,
hyperuricemiaanduratedepositsonkidneys,heart,pericardium,liverand
spleen
Microscopiclesion:acutetubularnecrosischaracterizedbyproteinaceousand
uratecasts,heterophilinfiltrationandfocalnecrosisoftubularepithelium
Mildtomoderatefattychangeandglycogendepositioninhepatocytes
resultinginyellowenlargedlivers

15. Pathology
SubacuteochratoxinAmycotoxicosis:
characterizedbyincreasedweightofliverandkidneyanddecreased
weightoflymphoidorgans
Microscopiclesionsinkidneyincludehyperplasiaoftubularepithelium
andinterstitialinflammation
Liver:fattychangeinhepatocytes,associatedwithanincreasein
glycogencontentofliverandskeletalmuscle
Chronicochratoxicosis:
Causesreducedrenalfunction

16. Clinical signs
•Depressed, dehydrated and polyuric(>4.0 ppm) and die in acute renal
failure
•Survivors become stunted are poorly feathered and have ncreased
clotting time, anemia and immunosuppression (>0.6 ppm)
•Loss of pigmentation and reduced weight gain, also decrease in egg
production and hatchability (>4.0 ppm)

17. Trichothecenemycotoxicosis
•Fairly common in poultry, but does not usually cause mortality
•It cause reduced feed intake, decreased growth and
immunosuppression
•Produced by many species of Fusarium, Stachybotrysetc
•Occur in wheat, maize and other grains
•It produce maximum toxin in cold (<20°C), moist condition
•80 chemically related trichothecenemycotoxinsbut 4 most known: T-
2, HydroxyT-2, Diacetoxyscirpenoland Deoxynivalenol.

18. Clinical signs
•Chickens develop ulcers at the commissures of the mouth, on the
hard palate near the beak and on the dorsal surface of the tongue
•Ulcerative stomatitis leads to decreased feed intake, reduced weight
gain
•Poor feathering, become anemic

19. Thank you