mycotoxicosis in horses

8/14/2019 Mycotoxicosis in Horses

1/26

Mycotoxicosis inHorses: A Worldwide

Concern. Its solutionDr.Kedar Karki


2/26

Background

Mycotoxins are toxic chemical compounds producedby some fungi as a defence system when they arethreatened. Horses are highly exposed tomycotoxins due to the variety of feedstuffs included

in their ration. Mycotoxicosis severity depends onduration of exposure, number of mycotoxins inpresence, housing conditions and health status ofthe horses. Mycotoxicosis may lead to

immunosuppression, reduction of the athleticperformances, cancers, and sudden death.


3/26

Background

Horse stalls contain high quantity of forages,

concentrates or bedding materials from cereals,

they are the ideal place for fungal growth and so

mycotoxins presence. Unfortunately, diagnosis isdifficult because clinical signs may be associated

with bacterial disease or unexplained behavioural

changes. However, preventive solutions do exist to

avoid mycotoxicosis; using modified clay is one ofthese solutions.


4/26

I- Mould growth, mycotoxinformation When moulds are threatened, they can

produce mycotoxins as a defence system.Therefore, the formation of mycotoxins is not

only favoured by the amount of moulds, butalso by the measurements taken to reducethem. Changes in temperature and humidity,use of fungicides generate a stress on the

moulds and can increase the amount ofmycotoxins.


5/26

I- Mould growth, mycotoxinformation The presence of mycotoxins is not easy to

demonstrate; they are not evenly spread and

therefore a negative test may not be reliable.

As the mycotoxins remain, even after themoulds have gone, the use of a mould

inhibitor in storage maybe much too late to

prevent mycotoxin formation and will notneutralize those that are already there.


6/26

II- Mycotoxicosis in theequine world Horses are selective grazers and normally

graze some areas like a golf green while

leaving other areas (roughs) long and

defecating in them. In most cases, poisonousplants can be present in horse pastures and

the horses will not touch them unless there is

nothing else to eat (5).


7/26

II- Mycotoxicosis in theequine world This intensive grazing on specific grasses involves a

symbiosis between the intensive grazed grassesand a fungus in order to grow and to survive. Thefungi are called endotoxins and they induce a lack of

palatability and toxicity for the horses at everyphysiological stage. Those endotoxins are part ofthe mycotoxins family which are not only restrictedto grains. Table 1 describes which mycotoxins maybe found according to the feedstuff. Pasturegrasses, hay, straw and stubble can all support thegrowth of various fungi (4).


8/26

II- Mycotoxicosis in theequine world Moulds tend to develop in isolated pockets ("hot

spots) in the stored commodities. After having beenconsumed by animals, there is no more evidence oftheir existence. Consequently, accurate concentration

of mycotoxins in the feed is difficult to determine dueto this heterogeneous concentration. From theirbedding material to the ryegrass they graze, horsesare daily exposed to mycotoxins. Moreover, equinesare simple stomach herbivores and they are

considered as more sensitive than the ruminants tomycotoxicosis because nutrient absorption occursprior to fermentative digestion (3).


9/26


10/26

II- Mycotoxicosis in theequine world Mycotoxins problem requires a different

approach in equines if compared to otherfarm animals. These other species are bred

for meat and/or milk yield and have arelatively short lifetime while in most cases,the horse is bred for athletic performance,conformation, temperament, beauty and/or

durability (1).


11/26

II- Mycotoxicosis in theequine world Although the effects of mycotoxins on horses are not well

documented in scientific literature, in field situations, apparentmycotoxin problems appear to be significant (3) all over the world(USA, Argentina, Brazil, South Africa, Egypt, Europe, China,New-Zealand). Indeed, mycotoxins have been implicated in a

variety of health problems described in figure 1. Many effects ofhigh concentrations of mycotoxins are well known: likeleukoencephalomalacia (ELEM) and colic for instance. At verylow contamination levels however, mycotoxins already affect theimmunologic and digestive systems, as well as the reproductivetract.


12/26

II- Mycotoxicosis in theequine world ELEM is a disease known since 1850 in the

USA and characterised by a suddenapparition of multifocal nervous troubles

leading rapidly to death within 10 to 24 hours(2). In every case, symptoms (successiveexcitation and torpor) are linked to thedistribution of a mouldy feed (mainly corn and

its by-products) at winter time during whichration is complemented with grains andconcentrates.


13/26

II- Mycotoxicosis in theequine world This pathology is due to the presence of

fumonisins which is an endophyte fungi

colonizing the plants without any visual sign,

but intoxication may be detected by an initialphase of unpalatable ration and depression.

While late-gestation mares are known to be

very sensitive to the ergot alkaloids (5),leukoencephalomalacia has no predisposition

on age, sex or breed (2)


14/26

Figure 1:Mycotoxins andtheir effect on horses.


15/26

Review of World wide

Epidemiology of Syndrome In 1995, 38 horses died to moldy corn

poisoning in Kentucky and Virginia (U.S.A).

From 1995-2004, 75 horses affected byneurological disorder in Norway due tofeeding of moldy silage

Purdue Indiana,(U.S.A.)1/6 horse died due tomoldy corn poisoning from1997-2004


16/26


Epidemiology of Syndrome

Southern Brazil (spring of 1996)

3 males and 1 female; died (3 to 4 years old

thoroughbred horses)

native grass supplemented with 2 kg of

corn/horse/day.


17/26


Epidemiology of Syndrome

Brazil (1994)

41/58 died

caused by fumonisin concentration lowerthan 10 ppm.

Oaxaca, Mexico (1998) donkeys died showing a neurological

syndrome,


18/26


Epidemiology of Syndrome Iran (2003),

Equine Leukoencephalomalacia

Spain(1988)leukoencephalomalacia (eaten corn with a pinkishfungal growth)

The fumonisins were discovered in 1988 followingthe 1970 outbreak ofEquineLeukoencephalomalacia in South Africa.


19/26


Epidemiology of Syndrome North Carolina (1989)

white-tailed deer

Leukoencephalomalacia

moldy field corn (Fusarium moniliforme)

Moldy corn poisoning in mule Nepal 31mule

of 900 herd died in 2006


20/26

Post-mortem examination

Post-mortem examination Severe congestion of liver, lung, spleen,

heart, Serosangqinus fluid in thoracic cavity. Hemorrhage in stomach mucosa.

Preliminary cause of sudden death wassuspected for moldy grain poisoning.


21/26

Laboratory Investigation: Results

Penicillium, Aspergillus, Candida sppon

mycological media (CVL).

60-110 CFU/gm Penicillium colonies

recorded in feed samples.

(Department of Food Tech and Quality Control

Kathmandu)


22/26

Unacceptably High Fungal Levels Identified

in Horse Feeds

Common fungus

(Aspergillus, Fusarium, and Penicillium)

Equine feed(proposed limit of 104 cfu per gram).


23/26

III- Classical preventive

measures againstmycotoxicosis

Until now, no treatment does exist for this mycotoxicosis.Therefore prevention stays the best solution by:

Adopt good cultural practises. Use a mould inhibitor. Remove the contaminated raw material, or incorporate it in low

dose in the final ration. Remove the horse from the infected pasture. Incorporate a mycotoxin inactivator with a large scale of

efficiency either in preventive or in curative situation withdemonstrated reliability even at low dosage.

As prevention is the best way to beat mycotoxins, a dailyincorporation of the mycotoxin deactivator is recommended toguarantee the prevention of detrimental effects of mycotoxins.

Simultaneous use of liquid toxin binder liketoxolivum,hepatocare,immunocare, are beneficial too


24/26

Treatment and Control Measure

advised Advised for proper drying of grain

before feeding.

Commercial toxin binders, (Varishta,Toxicurb) @ 1kg/tone of grain for15days along with Liver tonic,

(Hepatocare,bioliv), Immunomodulaters,(immunocare), Promin,Vitamin Bcomplex).


25/26

Conclusion

Raw materials contamination is unavoidable under certainenvironmental conditions and, due to its housing conditions andits feeding behaviour; horses must face to a long-term expositionto multicontaminated feed. Acute mycotoxicosis is easily todiagnose but often lethal; the main problem of mycotoxins is thattheir toxicity synergism and their detrimental impacts start at very

low levels. Prevention is the solution to avoid horses death! Toreduce the detrimental impact of mycotoxicosis, solutions doexist and the inclusion of a mycotoxin inactivator with a largespectrum of efficacy as MT.X+ appears to be the best and themost reliable protection for animal health and productivity.


26/26

Sources:

1) Kyle E. NEWMAN. 2006. Effects of mycotoxins in the equine what we know and what we do notknow. The World Mycotoxin Forum, the fourth conference November 6-8, 2006, Cincinnati, Ohio, USA.

(2) J.D. BAILLY, I. RAYMOND, P. LE BARS, Y. GUYOMARD, J. ABADIE, J. LE BARS, P. GUERRE, M.DELVERDIER et V. BURGAT. 1996. Leucoencphalomalacie des quids Cas rapports au CNITV.Revue Md. Vt. 1996, 147, 11, 787-796.

(3) M.B. GENTER, W.M. HAGLER, J.A. HANSEN, B.A. MOWREY, F.T. JONES, M.H. POORE, and L.W.WHITLOW. Effects of mycotoxins on horse health and productivity.http://www.ces.ncsu.edu/gaston/Agriculture/mycotoxins/mycohorse.html, consulted the 10/10/2007.

(4) B. WRIGHT. 2005. Molds, mycotoxins and their effect on horses.http://www.omafra.gov.on.ca/english/livestock/horses/facts/info_mycotoxin.htm, consulted the 03/04/2007.

(5) B. WRIGHT. 2004. Common plant poisonings of horses and their investigation.http://www.omafra.gov.on.ca/english/livestock/horses/facts/info_plantpois.htm, consulted the 10/10/2007.

(6) R. HAVENAAR and H. DEMAIS. 2006. Efficacy of sequestrant / chelator Amadite, in the binding ofmycotoxins during transit through a dynamic gastrointestinal model (TIM) simulating the GI conditions ofpigs. The World Mycotoxin Forum, the fourth conference November 6-8, 2006, Cincinnati, Ohio, USA.

(7) B.H.N. PHUC. 2007. Effects of inclusion MT.X+ in the diet on performances of sows. University ofAgriculture and Forestry, Thuduc, Ho Chi Minh City. Vietnam.

mycotoxicosis in horses

Documents