Use of chick embryos for prediction of embryotoxic effects of mycotoxins in mammals]

Embryotoxic effects of 25 mycotoxins were investigated in two-, three- and four-day chick embryos; the results were evaluated on the eighth day of development. The embryotoxicity ranged from 0.0001 to 0.1 microgram per embryo in T-2 toxin, aflatoxin B1, G1, B2 and M1, cytochalasin E, ochratoxin A and PR-toxin; from 0.1 to 1.0 microgram per embryo in sterigmatocystin, aflatoxin G2, vomitoxin (4deoxynivalenol), patulin, rubratoxin B, secalonic acid D, mycophenolic acid, and from 1.0 to 100 micrograms per embryo in penicillic acid, cyclopiazonic acid, tenuazonic acid, citrinine, brevianamide A, zearalenone, fusaric acid, griseofulvin, kojic acid and 8-methoxypsolaren. Acute cardiotoxic effects were observed in PR-toxin, patulin, rubratoxin B, penicillic acid, citrinine and zearalenone. Teratogenic effects with a spectrum of different embryonal malformations occurred in T-2 toxin, ochratoxin A, PR-toxin, patulin, secalonic acid D, mycophenolic acid and citrinine. The embryotoxic effects demonstrated in chick embryos correlated with the well-know literary data on mammals. Considering the different chemical composition and biological effects of mycotoxins, we suppose that the embryotoxicity test of chick embryos will also be suitable for testing other biologically active substances in the environment.     

Sarcocystosis in lambs]

We studied the problems of sarcocystosis of lambs in regard to the transfer of antibodies over ewes to lambs. Antibodies in the blood serum of 26 ewes found out by help of indirect immunofluorescent reaction (NFR) varied within the range from 640 to 5120 titres, while in six cases their level was higher than in blood. In none of new-born lambs there were proved antibodies to the sarcocystosis before the drinking of colostrum but three days later we already detected antibodies in the dilution 1:4 to 1:128. Then we studied the titre dynamics of antibodies in weaned lambs. In the age of 10-18 weeks we proved only low titres of antibodies, from the 20th to the 24th weeks the titres gradually increased and from the 26th to the 30th weeks the level of antibodies increased significantly (5120 titres) with its maximum on about the 28th week. Animals had no clinic symptoms of disease. In the other part of the work we examined the muscular substance of 342 lambs, killed in the slaughter house, by a digestive method and we carried out the blood serologic examination (NFR). Microcysts were found out in 35.67% of lambs while macrocysts were so in none of them. Specific antibodies of sarcocystosis were detected in 94.44% of young animals. A high discrepancy of the both methods (61.69%) in young animals is a result of a significant antibody reaction at still undeveloped muscular cysts.     

Pathologic changes in the lungs of deer spontaneously infected with nematodes from the Protostrongylidae family]

Lungs of 30 animals of the red deer (Cervus elaphus hippelaphus) attacked by parasitic helminths were submitted to a histological examination, and the changes which were caused by the nematodes of Protostrongylidae family were estimated. The lungworm Varestrongylus sagittatus (Mueller, 1891) creates hatching tubercles of a dark-red or yellow-green and even ochre colour. The lobular catarrhal bronchopneumonia is a histological correlate. In hatching tubercles there are located adult nematodes, ova of 46 x 27 microns and larvae of the 1st stage. For the infection of the Elaphostrongylus cervi nematodes (Cameron, 1931), the typical changes are those of the character of disseminated interstitial pneumonia. In the pulmonary tissue affected in such a way, there are numerous haemorrhages often visible microscopically. In the capillaries of interalveolar septa there are ova of E. cervi that reach up to 83 microns in dependence on the degree of their development and in alveoli there are larvae of the 1st stage. Adults do not occur in lungs.     

The effect of temperature and relative humidity on survival of eggs of the cestode, Monieza expansa (Rudolphi, 1810)]

The survival of Moniezia expansa eggs in the droppings of lambs was investigated at various temperatures in laboratory conditions and on test plots outdoors. The optimum temperature of the livability of M. expansa eggs in laboratory conditions is 5 degrees C; at this temperature 10% of oncospheres survived after 161 days. At the temperatures of 10, 25, 35 degrees C the oncospheres survived 105, 28, 46 days respectively, at -12 degrees C it was 28 days. It was for 21 and 35 days that on the test grassy plots the eggs of M. expansa survived in the droppings of lambs in the summer months of July and August at the average air temperatures of 15.7-18.2 degrees C and relative humidity of 67.7-74.3%. In autumn in September and October, at the average temperatures of 5.8-14.6 degrees C and relative humidity of 65.3-76.7% the oncospheres survived for 49 to 91 days. The M. expansa eggs in the droppings of lambs were able to survive on the test plot. The living oncospheres were demonstrated for 119 days from November 1987 to March 1988, and for 175 days till May by means of experimental infection of intermediate hosts.     

Long-term administration of the mycotoxin, ochratoxin A in chickens and the residues in the meat and animal feed]

A feeding trial was performed with chick broilers (cockerels). The feed with an addition of 850 micrograms ochratoxin A (OA) per kg was administered for six weeks. The feeding of the chicks stopped twelve hours before slaughter (in keeping with slaughter technology for chicks). Blood, liver and kidney samples were taken. At the end of trial the level of OA residues in the samples did not exceed 5 micrograms per kg. In other trials the dynamics of OA residues in the blood plasma of chicks was investigated after i.v. implantation at an amount of 2 and 20 micrograms per chick (1.5 kg lw.). An open two-compartment model was used to estimate toxicokinetic parameters. The half-time of elimination (t1/2(beta)) was about 3.3 hours. The high total clearance (CL) of 34.2 ml/min/kg lw. and apparent distribution volume (Vd(area)) of 9.8 l/kg lw. demonstrate rapid distribution to the tissues and rapid OA elimination. The results document that neither at a long-term intake of feed contaminated to the level of 850 micrograms OA per kg will the present hygienic limits of residues for foods be exceeded (5 and 20 micrograms per kg) if the principles of correct slaughter technology are observed. The blood of chicks used as feed is not an important source of OA in this case.     

Dissemination and survival of endoparasite embryos in the environment]

Pig farms with the annual capacity from five to 20 thousand head represent one of the crucial fields of agriculture influencing the environment in the CSFR. Daily production of large amounts of liquid excrements (150-300 m3), as a result of high concentrations of animals, poses not only technical but also sanitary problems closely related to the animal and man's health. In a long-term (267 days) field study the authors followed the development and survival of eggs of the model helminth Ascaris suum, contamination of the environment with the propagative stages of pig enteronematodes and possibility of their devitalization in a mechanico-chemico-biological waste-water treatment plant. Eggs of A. suum placed in the soil to the depth of 10 to 60 cm in November (1987) did not develop in winter months. Their development continued in spring months--at soil temperatures of 8.6 degrees C (at 5 cm depth) or 8.9 degrees C (at 20 cm depth). The embryonated eggs were found out at the beginning of the 20th decade of the experiment (May, 1988). The most positive samples on the investigated pig farm were found out in the vicinity of the central reservoir for waste water, showing the presence of both unembryonated and embryonated eggs of A. suum and Trichuris suis, with sporadic occurrence of Oesophagostomum dentatum L3 larvae. As demonstrated by our results, the tested waste-water treatment system complies only with the requirements of water management--with respect to the absence of the endoparasite propagative stages in the treated water.(ABSTRACT TRUNCATED AT 250 WORDS)     

Botulism in birds living in an aquatic environment in Nové Mlyny in the Breclav District

Epizootic of wild water birds caused by the toxin Clostridium botulinum of C type occurred in extensive shallow artificial lakes of the Nové Mlyny dam system from May to October 1988 and later on from February to early April 1989. In total more than 3,000 dead or dying birds of 44 species were found, the following orders were prevailing: Anseriformes (56%), Lariformes (33%), Charadriiformes (6%) and Ralliformes (4%). Botulotoxin was detected at high concentrations in sarcophagic fly larvae of Calliphora vomitoria and Lucilia sericata which were collected in bird cadavers, but it was not found in different components of the aquatic environment (water, submersed vegetation, phytoplankton, zooplankton, Gastropoda, Crustacea, Oligochaeta, larvae of Odonata, Chironomidae and Ceratopogonidae). Future development of the epizootic situation in the Nové Mlyny artificial lakes will depend on the water level and meterological conditions in the critical period (May to September).     

Comparison of different media for the isolation of small ruminant strains of Mycobacterium paratuberculosis

Two different egg based media, with and without the incorporation of sodium pyruvate, were used to isolate M. paratuberculosis from sheep, goat and cattle samples obtained at our laboratory for two years. Both media were adequate for bovine material, with a slightly improved isolation rate for Herrold's egg yolk medium incorporating sodium pyruvate; however, most of the small ruminant strains grew only on L?wenstein-Jensen medium without sodium pyruvate. Those results point out the need to use different media when working with small ruminant samples and provide further evidence for the existence of different varieties of M. paratuberculosis causing paratuberculosis in cattle and in small ruminants.     

Pathogenesis of experimental combined infections with Isospora suis and rotavirus in conventional and gnotobiotic piglets

51 gnotobiotic and 63 conventional, one-, or two-days-old piglets were divided into five groups and infected orally either with Isospora suis or rotavirus alone, or with both agents simultaneously or successively with alternative sequences and various intervals. 15 gnotobiotic and 10 conventional piglets served as controls. The development of small intestinal lesions after infection with I. suis was biphasic. The dominant alteration resulting from rotavirus infection was villus atrophy, considerably more pronounced and extensive in gnotobiotic than in conventional piglets. Synergistic action of I. suis and rotavirus was manifested both clinically, and morphologically. This action culminated at the time of the actual, or presumed development of merogony of I. suis, i.e. on DPI 3 to 5. The action develops only if the intestinal epithelium is damaged functionally and morphologically by a preceding rotavirus infection. It is concluded that the synergistic action is based on a competition of rotavirus and I. suis for mature, enzymatically active absorptive cells.     

Avascular necrosis of the femoral heads in a red panda (Ailurus fulgens fulgens): possible Legg-Calve-Perthes disease.

A 17-mo-old captive-born female red panda (Ailurus fulgens fulgens) presented with a sudden onset of lameness in its left hind leg was diagnosed radiographically as having possible severe, bilateral Legg-Calve-Perthes disease with fracture of the great trochanter of the left femur. Surgical repair of the fracture was performed using pins and a tension band wire through a lateral approach to the hip. This is the first case reported at Madrid Zoo-Aquarium, where 63 individuals have been bred over 15 yr.