Protection against enzootic pneumonia of pigs: intraperitoneal inoculation with live LKR strain of Mycoplasma hyopneumoniae

Pigs obtained from a mycoplasma-free piggery were randomised into 4 groups of 9. Groups 1 and 2 were injected by the intraperitoneal route with liquid culture of the LKR strain of Mycoplasma hyopneumoniae. Group 1 was injected once and group 2 twice. Group 3 was made up of pigs inoculated by the intranasal route with the virulent Beaufort strain of M. hyopneumoniae; they served as the source of infection for the challenge. Group 4 were uninfected, uninjected controls. Six weeks after the last injection, groups from 1 to 4 were placed in contact. Seven of the pigs in the 1-dose group and 6 in the 2-dose group were free of lesions at necropsy 6 weeks after challenge. Of the two pigs with lesions in the 1-dose group one had only a small lesion but the other had extensive lesions; it had not shown an antibody response after injection of culture. The lesions in the 3 pigs in the 2-dose group were all small. All 9 control pigs had lesions which varied from medium to large in size. The difference in the incidence of pneumonia between the injected and control groups was significant (P less than 0.05) and the proportion of severely affected pigs in the vaccinated groups was significantly lower (P greater than 0.01). There was no difference between those given one dose of vaccine and those receiving 2 doses.     

Anatomical and cellular responses of Pinus monticola stem tissues to invasion by Cronartium ribicola

White pine blister rust (Cronartium ribicola) causes extensive damage to white pines and their associated ecosystems across North America. The anatomical and cellular characteristics of C. ribicola colonization in Pinus monticola branch and stem tissues were studied as a basis for understanding host tree reactions that may be related to resistance. Samples examined showed typical fusiform swelling and some had produced aecia. The reaction of phloem and xylem tissues was compared with non-infected tissue using light and electron microscopy. Cortical parenchyma and phloem polyphenolic parenchyma cells underwent mitotic division, cell swelling, and ca sixfold greater accumulation of phenolic compounds in colonized vs. control stems. In the cortex and secondary phloem, haustoria were common in parenchymatous cells, and hyphae were abundant in the intercellular spaces, but cell death was rare, unless aecia had ruptured the stem cortex. Hyphae were also common in xylem rays, tracheids and between tracheids. Disease-induced changes in the cambial zone included development of cambium-derived xylem traumatic resin ducts. Results demonstrate that diverse host defence responses were activated in the bark of apparently susceptible trees, but lack of mechanical damage by C. ribicola to the phenol-containing host cells and the resin duct system allowed extensive colonization and development of aecia despite elicitation of these stem defences. Interactions between P. monticola and C. ribicola are discussed and compared with other conifer–fungus pathosystems.     

Methyl jasmonate induces changes mimicking anatomical defenses in diverse members of the Pinaceae

Conifers have defenses such as the production of phenolic compounds and resins that can be induced by bark beetles and other invading organisms, but the signaling agents involved are unknown. The anatomical effects of methyl jasmonate (MJ), a potent inducer of certain plant defenses, were compared with wounding of the bark of 12-15-year-old trees of five conifer species. Wounding in all species resulted in tissue necrosis and wound periderm development immediately around the wound site. One cm from the wound, swelling of phloem polyphenolic parenchyma cells and phenolic accumulation were observed in Pseudotsuga menziesii (Mirb.) Franco, Picea pungens Engelman, Larix occidentalis Nutt. and Pinus monticola Douglas ex D. Don, but not in Taxus brevifolia Nutt. Traumatic resin ducts were formed in response to wounding in three species of Pinaceae, but not in P. monticola, which formed irregular clusters of cells rather than ducts. Taxus brevifolia did not form resin ducts in response to either wounding or MJ treatment. In the Pinaceae species studied, surface application of 100 mM MJ caused similar anatomical changes to those observed in response to wounding, including phenolic accumulation, cell swelling and traumatic resin duct formation, but it did not induce a wound periderm. Traumatic resin ducts differed in size among the study species, ranging from small in L. occidentalis to very large in P. menziesii. In P. menziesii, P. pungens and L. occidentalis, traumatic resin ducts were more abundant after MJ treatment than after wounding. We conclude that the octadecanoid pathway is likely involved in defense responses in stems of the Pinaceae, but not necessarily in other taxa.     

Double-outlet right ventricle in a 10-month-old Friesian filly

A 10-month-old Friesian filly had a presentation that was consistent with chronic left- and right-sided congestive heart failure. Clinical pathology findings included abnormal haematological and biochemical variables, abnormal blood gas values and increased serum concentration of cardiac troponin I. Echocardiography revealed cardiac chamber dilation and dextropositioning of the aorta. Radiography revealed a generally enlarged heart and pulmonary interstitial infiltration. These findings were supported at necropsy and the diagnosis of double-outlet right ventricle was confirmed. The pathological changes and physiological responses subsequent to double-outlet right ventricle have not previously been described in detail in horses. Clinical progression closely resembles that seen in humans, in whom antemortem diagnosis relies on echocardiography. In horses, complex cardiac disease presents a diagnostic challenge to the clinician. Appropriate therapy must be based on an accurate diagnosis.     

Recovery and Cryopreservation of Epididymal Sperm of Plains Bison (Bison bison bison) as a Model for Salvaging the Genetics of Wood Bison (Bison bison athabascae)

The objective of this study was to optimize recovery and cryopreservation of epididymal sperm from plains bison, as a model for wood bison. In Phase 1, cauda epididymides were recovered from bison (n = 14) immediately after slaughter, minced and incubated in Sp-TALPH buffer for 3 h at 36°C. The resulting sperm suspensions were cryopreserved in Triladyl^®, using a protocol for bovine semen. In Phase 2, epididymal sperm were cryopreserved in either Triladyl^® or Andromed^®. The mean (±SD) estimated number of sperm recovered was 468 ± 207 × 10⁶. There was an increase (p < 0.05) in the proportion of sperm with normal morphology between initial recovery and after extension (52.4 ± 4.6 vs 69.7 ± 2.4%), with a concurrent decrease (p < 0.05) in the proportion of sperm with distal droplets. Median values for progressively motile sperm in post-thaw samples (60%) were lower (p < 0.05) than that after extension or after chilling (70% for both). The mean percentages of viable sperm and of sperm with an intact acrosome were lower (p < 0.05) for frozen-thawed samples (38.7 ± 2.8 and 85.2 ± 1.1) compared with extended (66.2 ± 2.2 and 92.4 ± 0.9) or chilled (63.7 ± 2.5 and 90.0 ± 1.0) samples. Rates of cleavage, morulae and blastocyst production were not significantly different for chilled (70.9, 38.7 and 8.0%) vs post-thaw sperm (73.0, 46.0 and 6.3%). There was no significant difference between extenders for most sperm characteristics. In conclusion, we developed a functional protocol for the recovery and cryopreservation of epididymal sperm from plains bison, which may have implications for the genetic preservation of wood bison.     

In vitro Maturation of Oocytes from Santa Ines Ewes Subjected to Consecutive Sessions of Follicular Aspiration by Laparoscopy

The success of embryo production in vitro depends upon the use of an efficient oocyte retrieval technique, and the best results have been obtained by laparoscopic aspiration. The aim of this study was to evaluate the effect of consecutive sessions of follicular aspiration on the quantity, quality and in vitro maturation competence of oocytes obtained from ewes subjected to hormonal stimulation. Six Santa Ines ewes underwent nine sessions of follicular aspiration by laparoscopy with a 7‐day interval between sessions, totalling 56 aspirations. After 24 h of culture, oocytes were stained and classified according to the stage of nuclear and cytoplasmic maturation. Oocyte retrieval rate was 61.4 ± 2%, resulting in a total of 249 oocytes. No significant variation was observed between sessions (p > 0.05). The average number of oocytes retrieved from each ewe was 6.4 ± 2 per session and 42 ± 4 in total. No significant difference was observed between the frequencies of the different stages of nuclear maturation: 32.72% mature, 40.74% immature and 26.54% degenerated/indeterminate oocytes; however, a significant difference was observed between the frequencies of the different stages of cytoplasmic maturation: 10.7% mature, 73.25% immature and 16.05% degenerated/indeterminate oocytes. No significant difference was observed in nuclear or cytoplasmic maturation between the weeks of procedure. We conclude that after nine consecutive sessions of follicular aspiration, the quantity and quality of retrieved oocytes remained unchanged as well as the levels of nuclear and cytoplasmic maturation obtained, demonstrating the viability of this technique for repetitive follicular aspirations on the same donor.