Growth performance and the pattern of glycolytic enzymes in the blood plasma were assessed during experimental Sarcocystis cruzi infection (1 x 10(5) sporocysts per calf) in six calves; five calves served as noninfected controls. At slaughter (68 or 88 days post infection), carcass weight, dressing percentages and several parameters of meat quality (pH, color brightness, rigor, water absorbing capacity, water binding capacity) were recorded. Moreover, enzyme activities were measured in muscle homogenates. Weight gain was significantly impaired by the infection. Activities of lactate dehydrogenase (LDH) and aldolase (ALD) significantly increased in the blood plasma of the infected calves during the chronic stage of the disease, while glucose-6-phosphate dehydrogenase (G6PDH) and isocitrate dehydrogenase (ICDH) were not significantly altered. This was accompanied by a significant decrease of enzyme activities in the Musculus longissimus dorsi (LDH, ALD), in the diaphragmatic musculature (ALD, G6PDH) and in the heart (LDH, ALD). Activities of LDH, ALD, ICDH and G6PDH were visualized by enzyme histochemistry within the developing sarcosporidial cysts. However, isoenzymes of parasite origin could not be demonstrated by agar-gel electrophoresis of muscle homogenates or blood plasma. It is concluded that sarcocystiosis of even moderate severity alters the performance of calves but not meat quality. Leakage of glycolytic enzymes from the affected muscles is the probable cause of increased plasma enzyme activities. Although these enzymes are also synthesized by the parasite, the contribution of parasite-derived enzymes to the observed changes of enzyme patterns remains in question.

Coccidia were isolated from a commercial broiler farm with a history of suspected drug resistance. The sensitivity profiles of the Eimeria spp. isolates against the anticoccidial drugs nicarbazin (NIC), narasin (NAR), halofuginone (HAL), salinomycin (SAL), meticlorpindol plus methylbenzoquate (MET), and monensin (MON) at the recommended dose levels were followed in three battery trials (B1, B2, B3) corresponding to a field study over three periods of commercial broiler keeping (F1, F2, F3). Shuttle programs were performed in F1 (NIC/MON) and in F2 (MET/MON) while only SAL was used in F3. Eimeria acervulina and E. tenella were isolated from indicator birds in F1 while only E. acervulina could be found during F2 and F3. In trial B1 the isolate from F1 was identified as resistant against HAL and partly resistant against NIC and MON, the two drugs that were used in F1. Following the replacement of NIC in the starter feed by MET the respective isolate from F2 showed no resistance against ionophores (trial B2) while partial resistance against HAL was still present. Since SAL was the most efficient drug in B1 and B2 only this drug was applied in F3. Apart from a resistance against HAL no resistance against any of the other tested anticoccidials was found in the isolate from F3. SAL controlled coccidiosis efficiently in the field and best productivity was recorded in F3. This study shows that battery trials have a good predictive value in respect to the efficacy of anticoccidials under the conditions of commercial broiler production.

The effects of mild Sarcocystis miescheriana infection on blood enzymes and body weight were compared in stress-sensitive (halothane positive) and in stress-insensitive (halothane negative) pigs. Ten halothane-positive pigs (Group A) and ten halothane-negative pigs (Group C) with a mean body weight of 36 kg were each inoculated orally with 50 000 sporocysts of S. miescheriana. Twelve halothane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Five days before infection (a.i.) and 58 days post infection (p.i.) all pigs were myostress challenged (creatine kinase test). During the whole period of the experiment (3 weeks a.i. to 13 weeks p.i.) body weights were determined and blood samples taken at weekly intervals. Creatine kinase (CK), aspartate aminotransferase (ASAT) and Sarcocystis antibody titres were determined. The infection induced slighly elevated temperatures (max. 42.8°C) and transient reduced food intake during the 2nd and 3rd week p.i. The CK values of the infected pigs in Groups A and C increased from Day 28 p.i. onwards, and were significantly higher than those of the pigs of the non-infected controls (Days 35–77 p.i.). The ASAT values of the infected groups (A and C) increased from Day 21 p.i. onwards, and were significantly higher than those of the non-infected controls from Days 28–77 p.i. The myostress injection at 5 days a.i. (1st CK test) resulted in significantly higher CK and ASAT values in stress-sensitive pigs. The myostress injection at 58 days p.i. (2nd CK test) induced significantly increased plasma enzyme activities in the infected pigs of both the halothane-positive and halothane-negative groups. The mean body weight of the infected pigs was significantly lower than of the non-infected controls (Days 42–84 p.i.).

Ten halothane-positive pigs (stress sensitive, group A) and ten halothane-negative pigs (stress insensitive, Group C) with a mean body weight of 36 kg were each inoculated orally with 50 000 sporocysts of Sarcocystis meischeriana. Twelve halothane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Thirteen weeks post infection (p.i.) the lean:fat ratios of the pigs of the infected groups A and C were lower (A 1:041 ± 0.09; C, 1:0.50 ± 0.10) than those of the pigs non-infected groups B and D B, 1:0.50 ± 0.08; D, 1:0.55 ± 0.08). The back-fat thickness, the fat thickness ‘A’ and the fat thickness ‘B’ were thinner in infected pigs than in non-infected pigs. The difference in Lendenstärkespeckquotient (Loin Fat Thickness Quotient) (LSQ) between infected and non-infected pigs was not statistically significant. The values of the water-holding capacity were lower in infected pigs than in non-infected pigs, the difference being statistically significant only in the halothane-negative groups (C, 0.45 ± 0.02; D, 0.48 ± 0.04). The water-absorbing capacity was significantly higher in the infected groups (A, 5.92 ± 0.02; B, 2/26 ± 3/99%; C, 8.96 ± 2.90%; D, 4.97 ± 2.51%). In conclusion, it can be said that there was a slight tendency towards a better carcass quality and a better water-binding capacity in infected pigs, although this was combined with reduced growth rates.

Ten halothane-positive pigs (Group A) and ten halothane-negative pigs (Group C) were each infected per os by 50,000 sporocysts of Sarcocystis miescheriana when they had reached a mean body weight of 36 kg. Twelve halothane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Thirteen weeks p.i. (post infection), the pigs were slaughtered and the carcass weights and the number of cystozoites in several muscles were determined. In addition, 11 parameters of meat quality were measured in Musculus longissimus dorsi (M.l.d.) and Musculus semimembranosus (M.s.): pH and temperature 30 min and 24 h p.m. (post mortem), electrical conductance 45 min, 60 min and 24 h p.m., colour brightness (FOP) and rigor values 30 min and 24 h p.m. Additionally, the AMP, ADP, ATP and lactate contents were determined in samples from the M.l.d. The mean carcass weights of the infected pigs (A: 79.9 +/- 6.9 kg; C: 76.3 +/- 11.6 kg) were lower than those of the pigs of the non-infected groups (B: 85.7 +/- 8.0 kg; D: 87.5 +/- 7.0 kg). The pH values at 24 h p.m. were significantly higher in the M.l.d. of infected pigs than in M.l.d. of non-infected pigs. Electrical conductance in the M.s. at 45 min p.m. was significantly higher in the halothane-negative infected pigs, but at 24 h p.m., the mean values of electrical conductance in the M.s. of the pigs of both infected groups were significantly lower than in the control groups. FOP values at 30 min p.m. were raised in the M.l.d. of the halothane-negative infected pigs, but at 24 h p.m., differences between infected and non-infected pigs could no longer be found. Mean rigor values were higher in the pigs of the infected groups at 24 h p.m., but the difference from the non-infected groups was not statistically significant. AMP was reduced only in the meat of halothane-positive infected pigs, while lactate was reduced in both infected groups. Using conventional methods for the determination of meat quality, the hypothesis of impaired meat quality in Sarcocystis-infected pigs could not be confirmed. The meat quality parameters investigated were, in part, better in infected pigs than in non-infected controls.

ZusammenfassungFünf Ponys wurden mit je 200 000 aus Hunden isolierten Sarkosporidiensporozysten oral infiziert. Die Hunde waren mit zystenhaltiger Muskulatur eines natürlich infizierten Pferdes gefüttert worden. Am 12. Tag p.i. wurde bei einem und vom 20. bis 22. Tag p.i. bei allen Ponys Fieber zwischen 39,8 °C und 40,5 °C beobachtet. Zwischen dem 51. und 70. Tag p. i. erkrankten 3 Ponys mit starken Bewegungsstörungen (Myopathie), Apathie und Freßunlust. Bis zum 63. Tag p. i. stieg die muskelspezifische Creatinkinase bei allen 5 Ponys auf das 4‐ bis 44 fache des maximalen Normalwerts an und blieb mit einigen Schwankungen bis zum 147. Tag p.i. erhöht. Ein Anstieg der Antikörpertiter wurde mit dem ELISA am 7. und mit dem IFAT am 21. Tag p.i. festgestellt. In beiden Tests erreichten die Titer zwischen dem 77. und 98. Tag p. i. Maximalwerte und nahmen danach kontinuierlich ab. Die klinisch manifesten Myopathien werden auf die experimentelle Sarkosporidieninfektionen zurückgeführt. Bei Myopathien kann möglicherweise auch unter natürlichen Bedingungen eine ätiologische Diagnose durch immun‐ und enzymserologische Untersuchungen gestellt werden.SummaryClinical signs, serum‐enzyme activity and the dynamics of antibody titres in horses with experimental sarcosporidial infectionsFive ponies were orally infected each with 200,000 sarcosporidial sporocysts. The sporocysts originated from dogs that had been fed muscles of a naturally infected horse. One pony had fever on day 12 p.i. and all ponies had temperatures between 39.8 and 40.5 °C from day 20 to 22 p.i. Three ponies had motor disturbances, apathy and anorexia between day 51 and 70 p. i. In all ponies the muscle specific creatinekinase reached a four‐to forty‐fourfold increase as compared to normal values by day 63 p. i. and remained at the high level until day 147 p. i. Antibody titres as measured with the ELISA became positive on day 7 p. i. and IFAT titres on day 21 p. i. Maximum values were reached in both tests between day 77 and 98 p. i. Thereafter the titres decreased continually. The observed clinical myopathy is considered to be caused by the experimental sarcosporidial infection. It seems possible to aetiologically diagnose clinical myopathy under natural conditions by means of immunoserological and enzymatic investigations.RésuméClinique, activité enzymatique et formation d'anticorps chez des chevaux infectés expérimentalement avec des sarcosporidiesCinq poneys ont été infectés chacun oralement avec 200 000 sporocystes isolés chez des chiens. Les chiens avaient été nourris avec une musculature contenant des kystes d'un cheval infecté naturellement. Une fièvre entre 39,8° et 40,5 °C a été observée chez un poney 12 jours p. i. Trois poneys sont tombés malades avec de graves troubles de locomotion entre le 51 e et le 70e jour p. i. (myopathie); ils ont également manifesté une apathie et une anorexie. Le créatinkinase musculaire spécifique a augmenté chez les 5 poneys jusqu'au 63e jour p. i. à des valeurs 4 à 44 fois supérieures à la normale et est restée élevée avec quelques variations jusqu'au 147e jour p, i. Une augmentation du titre des anticorps a été établie au 7e jour p.i. avec l'ELISA et au 21e jour p.i. avec le titre des anticorps en fluorescence indirecte. Les titres ont atteint des valeurs maximales dans les deux tests entre le 77 e et le 98e jour p. i. et diminuèrent ensuite continuellement. Les myopathies cliniquement manifestes doivent être attribuées aux infections expérimentales à sarcosporidies. Lors de myopathies, un diagnostic étiologique peut également être posé dans des conditions naturelles par des recherches immunologiques et en sérologie enzymatique.ResumenSobre la clínica, actividad enzimática y anticuerpogénesis en los caballos infestados experimentalmente con sarcosporidiosPor vía oral se infestaron cinco poneys con — cada vez — 200.000 esporocistos que fueron aislados en perros. Los perros fueron alimentados con musculatura que contenía quistes de un caballo infestado naturalrnente. El día 12° p. i. se observó fiebre entre 39,8° y 40,5 °C en un poney y del día 20° hasta el 22° p.i. en todos ellos. Entre los días 51° y 70° p. i. enfermaron 3 poneys con trastornos graves de la locomoción (miopatía), apatía y anorexia. Hasta el día 63° p. i. aurnentó la creatinaquinasa músculo‐específica en todos los 5 poneys hasta 4—44 veces del valor máximo normal, perrnaneciendo incrementada con algunas oscilaciones hasta el día 147° p. i. El aurnento de los títulos de anticuerpos fue comprobado con la ELISA el día 7° p.i. y con la IFAT el día 21° p.i. En ambos tests alcanzaron los títulos valores máximos entre los días 77° y 98° p. i., disminuyendo luego de forma continuativa. Las miopatías clínicamente manifiestas se atribuyen a las infestaciones experimentales con sarcosporidios. Posiblemente también en las rniopatías habidas bajo condiciones naturales se podría establecer un diagnóstico etiológico mediante análisis inmuno y enzimoserológicos.