Complete article

Congenital nutritional myodegeneration in
a Cypriot mouflon (Ovis orientalis ophion)
lamb
P. LOUKOPOULOS1, I. IOANNOU2, N. KASSINIS3, S. GEORGIADOU2, H. PAPASTEPHANOU4,
E. KALDRYMIDOU1, N. D. GIADINIS5*
Pathology Laboratory, School of Veterinary Medicine, Aristotle University of Thessaloniki, GREECE.
Veterinary Services, Nicosia, CYPRUS.
Cyprus Game Fund Service, Limassol, CYPRUS.
4cp. FoodLab Ltd, 25 Polyfonti, 2040 Strovolos, Nicosia, CYPRUS.
5Clinic of Farm Animals, School of Veterinary Medicine, Aristotle University of Thessaloniki, GREECE.
1
2
3
*Corresponding author: [email protected]
SUMMARY
A five days old Cypriot mouflon (Ovis orientalis ophion) lamb was found
dead without premonitory signs in the Platania mouflon enclosure. Necropsy
revealed generalized pale discoloration of skeletal muscles and to a lesser extent of the myocardium. Extensive and severe muscular degeneration and necrosis were evidenced by histology. Liver selenium and vitamin E contents
were 0.23 mg/kg and 21 mg/kg, respectively. Based on the post mortem findings, the diagnosis of white muscle disease was established and was presumptively attributed to vitamin E deficiency by comparison with usual
values obtained in other zoo ruminants. It is the first reported case of white
muscle disease in any mouflon species, and particularly in the wild Cypriot
mouflon that is endangered and under strict surveillance.
Keywords: Endangered species, Cypriot mouflon, congenital form, nutritional myodegeneration, selenium, vitamin
E deficiency.
RÉSUMÉ
Myopathie dégénérative nutritionnelle congénitale d'un jeune mouflon
Chypriote (Ovis orientalis ophion)
Un jeune mouflon chypriote (Ovis orientalis ophion) de 5 jours a été retrouvé
mort, sans signe prémonitoire, dans un enclos pour mouflons de Platania.
L'autopsie a révélé une pâleur généralisée des muscles squelettiques et à un
degré moindre du myocarde. Des lésions musculaires dégénératives et nécrotiques intenses et étendues ont aussi été mises en évidence à l’histologie. Les
concentrations hépatiques de sélénium et de vitamine E ont été respectivement de 0,23 mg/kg et de 21 mg/kg de foie. Le diagnostic de la « maladie du
muscle blanc » a été établi sur la base des observations post-mortem et l’étiologie en serait une carence en vitamine E par comparaison avec les valeurs
usuelles obtenues chez d’autres espèces de ruminants sauvages. Il s’agit donc
du premier cas rapporté de maladie du muscle blanc chez le mouflon, toutes
espèces confondues, et en particulier chez le mouflon chypriote qui est une
espèce menacée et soumise à une surveillance stricte.
Mots clés : Espèces menacées, mouflon chypriote, forme
congénitale, myopathie dégénérative nutritionnelle, sélénium, carence en vitamine E.
Introduction
Nutritional myodegeneration (white muscle disease, WMD)
results from selenium and/or vitamin E deficiency and affects
a wide range of domestic and wild animal species including
sheep, goats, cattle, deer, horses, swine, poultry, rabbits, marsupials, monkeys, laboratory and exotic animals, monkeys and
even fish [8, 12, 15]. It is a degenerative disease of the striated
muscles, without neural involvement. Lesions are probably
initiated following free-radical damage [8, 20]. In ruminants,
two clinical forms of the disease are recognized, the congenital
and the delayed form [8, 12]. The former affects neonatal animals, which are stillborn or weak and usually die soon after
birth, while the latter affects animals older than 3 weeks of
age [12, 15].
The Cypriot mouflon or agrino (Ovis orientalis ophion) is
a wild sheep species endemic and unique to Cyprus. According to historical records, it has been present in the island for
at least 10,000 years and is of Asiatic origin. It is the largest
terrestrial mammal found in Cyprus [14, 21]. It is smaller than
other wild sheep, the male weighing 35-45 kg and the female
25-35 kg; the males bear supracervical horns while the females are hornless. The current mouflon population is estimated to be approximately 3,000 animals. Mouflon inhabit
the Paphos forest, a mountainous area of 620,000 ha in the
North-western part of the Troodos mountain range. Along
with the mouflon of Sardinia and Corsica (Ovis gmelini mussimon) it is the only forest dweller among the Caprinae [6,
14].
The species’ health is closely monitored by the Game Fund
Service in collaboration with the Department of Cyprus Veterinary Services. Under Cypriot legislation, it is a strictly protected species and has been included in Annex II/IV of 92/43
EU Habitats Directive, as a European priority species. It is
also referred as endangered under the International Union for
the Conservation of Nature 1996 Red list [18]. All deaths observed in recent years are recorded and its population status
monitored. Furthermore, the Cypriot mouflon is one of the
symbols of Cyprus, even featuring on the Cyprus Euro coin,
Revue Méd. Vét., 2012, 163, 8-9, 402-404
CONGENITAL NUTRITIONAL MYODEGENERATION IN A CYPRIOT MOUFLON
403
a fact that may indeed help its survival. On the other hand, it
can also be threatened by likely transmission of infectious
agents from domestic ruminants in shared pastures. To date,
there is little information on its physiology and pathology,
whether free-ranging or semi-enclosed.
adult males and one female mouflon sheep. The adults were
free-ranging in a 2.7 hectare area and were additionally provided with alfalfa hay ad libitum and concentrate mixture notcontaining extra vitamins, macro- or micro- minerals, while
the aforementioned lamb was suckling.
To date white muscle disease has not been diagnosed in Cypriot mouflon or other mouflon species. This short paper describes a case of congenital white muscle disease in a Cypriot
mouflon lamb and its clinical and pathological findings.
POST MORTEM AND LABORATORY FINDINGS
Clinical Case
CASE HISTORY
A five days old mouflon lamb was found suddenly dead in
the Platania mouflon enclosure in Cyprus. No signs of disease
were observed prior to death. The enclosure also contained 3
Necropsy revealed a generalized pale discolouration of skeletal muscles (figure 1), and myocardium. Histopathological
examination showed severe and extensive myodegeneration
and necrosis of the skeletal muscles, as well as extensive mineral deposition (figures 2a and 2b); degeneration was also
observed in the myocardium, albeit to a markedly lesser degree and extent. Based on the above, the diagnosis of white
muscle disease was established. Liver selenium and liver vitamin E contents (determined by fluorometry) were 0.23 mg/kg
and 21 mg/kg of liver weight, respectively.
Discussion
White muscle disease in the Cypriot mouflon lamb was
diagnosed based on the observed gross and histological lesions. Findings similar to the ones described here have been
described for white muscle disease in other ruminant species,
in Greece and other countries. Sudden death can be attributed
to heart failure, a condition that also seems to be common in
other WMD cases in ruminants [9, 15].
FIGURE 1: Necropsy of a 5 days old Cypriot mouflon lamb, suddenly
dead, showing generalized and severe pale discolouration of skeletal
muscles (arrows).
To date, most reported cases of WMD in young animals of
various ruminant species, such as calves, lambs, kids and deer
calves have mainly been attributed to selenium deficiency or
combined selenium and vitamin E deficiency [1, 4, 15, 17].
However, a smaller number of WMD cases in lambs and zoo
ruminants have been attributed solely to vitamin E deficiency
[3, 5, 9, 10, 13, 19].
FIGURE 2: Severe and extensive muscular degeneration (yellow arrows) and necrosis (blue arrows) (a., Bar: 100 μm) as well as mineral
deposition (light and dark mauve areas) (b., Bar: 50 μm) in a 5 days old Cypriot mouflon lamb, suddenly dead. Haematoxylineosin.
Revue Méd. Vét., 2012, 163, 8-9, 402-404
404
In the present case WMD can be presumptively attributed
solely to vitamin E deficiency. Reference values for selenium
and vitamin E are not currently available for the Cypriot mouflon
or other mouflon species. However, although knowledge
based on sheep or other ruminants cannot necessarily be extrapolated for the Cypriot mouflon, the liver selenium value
obtained falls within the usual values measured in various
other ruminant species [11, 17] and may therefore be presumed
to be normal. On the contrary, the liver vitamin E concentration
measured was lower than the reported usual values for lambs
[5]. However, the vitamin E content in liver measured in the
reported case was not as low as in lambs with clinically manifested vitamin E deficiency [5]. This could indicate increased
requirements for vitamin E in the Cypriot mouflon. A similar
condition occurs in other ruminant zoo species, such as Bovidae (antelopes), Cervidae (deer species), Elephantidae and
Rhinocerotidae [2]. Firmer conclusions, however, cannot be
drawn at this stage due to the lack of reference values for healthy
free-ranging and semi-enclosed Cypriot mouflon. The findings
may not be surprising given that the disease is well described
in domestic sheep; however, as stated above, the mouflon is a
wild sheep species, little is known about its pathology, and
there is no information regarding its nutritional needs when
semi-enclosed.
Apart from expanding on comparative aspects of ruminant
pathology, this report is, to our knowledge, one of the few reports of disease concerning the Cypriot mouflon [7]. In endangered animals, diseases may constitute the single greatest
threat to the species’ survival [16]. The survival of the species
will in part depend on the maintenance of the population in
good health, whether free-ranging or enclosed. Recognition
of the conditions affecting the Cypriot mouflon, such as the
one described here, is a necessary step in the design, implementation and, ultimately, the success of health monitoring
strategies.
As a conclusion, congenital white muscle disease can cause
sudden death in neonatal Cypriot mouflon lambs. The diagnosis is based on the gross and histological findings that are
similar to the ones described in WMD in other species while
the disease may be attributed to vitamin E deficiency. Recognition of the conditions affecting the Cypriot mouflon, such
as the one described here, is a necessary step in the design,
implementation and, ultimately, the success of health monitoring strategies.
Acknowledgement
The authors thank Dr Marie Savina-Rolland for her helpful
editorial input.
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