Haemophilus somnus-induced interference with bovine neutrophil functions

The effect of Haemophilus somnus on bovine polymorphonuclear leukocyte (PMN) function was examined in vitro with whole cells and fractions extracted from the surface of this bacterium. The ability of PMNs to iodinate protein and ingest Staphylococcus aureus was significantly inhibited in the presence of live cells, heat-killed whole cells or supernatant fluid from heat-killed cells, but not in the presence of washed, heat-killed cells. None of the fractions inhibited nitroblue tetrazolium (NBT) reduction by PMNs. The PMN inhibitory factors were further characterized. The material that inhibited S. aureus ingestion was found to be a heat-stable cell surface material of greater than 300 000 MW. The fraction inhibiting iodination of protein was found to be less than 10 000 MW.     

Corticosteroid-induced suppression of in vitro lymphocyte proliferation in four captive rhinoceros species.

Captive African black rhinoceroses (Diceros bicornis) are unusually susceptible to several diseases not commonly observed in any of the other three rhinoceros species maintained in captivity. The potential role of corticosteroids (either endogenously produced or exogenously administered) in the development of these sometimes fatal diseases has been questioned. In this study, the suppressive effects of two therapeutic corticosteroids (dexamethasone and hydrocortisone) on in vitro lymphocyte proliferation was examined in four rhinoceros species, including the Sumatran rhinoceros (Dicerorhinus sumatrensis, n = 3), Indian rhinoceros (Rhinoceros unicornis, n = 4), African black rhinoceros (n = 10), and African white rhinoceros (Ceratotherium simum, n = 5). Three blood samples collected from each rhinoceros 1 mo to 1 yr apart provided replicates for the study. Both dexamethasone and hydrocortisone suppressed (P < 0.05) lymphocyte proliferation stimulated by B-cell mitogens (pokeweed and lipopolysaccharide) and T-cell mitogens (phytohemagglutinin and concanavalin A). Suppressive effects of the glucocorticoids differed (P < 0.05) depending on the mitogen used to stimulate the lymphocytes. Overall, dexamethasone was a more potent suppressor of cell proliferation when compared with hydrocortisone (P < 0.05). However, black rhinoceros cell proliferation in response to any of the four mitogens was never completely suppressed, even in cultures containing the highest steroid concentration tested (10(-3) M). The effect of the two corticosteroids differed slightly among the rhinoceros species and subspecies tested, but there was no evidence that eastern or southern black rhinoceros lymphocytes were more sensitive to the suppressive effects of corticosteroids than the other rhinoceros species.     

Recombinant porcine somatotropin: an immunotoxicology study.

The present study was designed to determine the effect of recombinant porcine somatotropin (rpST; 5, 15, or 25 mg.pig-1.d-1 for 57 d) on a variety of immune function variables. We observed no significant effect of rpST treatment on the gross pathology of the pigs, histopathology of the immune system organs, total and differential white blood cell counts, lymphocyte blastogenic response to mitogens, or the neutrophil functions of chemotaxis, ingestion, reduction of cytochrome C, iodination, and antibody-dependent cell-mediated cytotoxicity. Those variables that were significantly affected by rpST treatment include a decreased hemoglobin and packed red blood cell volume (at some time points for all three rpST dosages), a decrease in plasma protein level at the 25-mg dose, a small increase in neutrophil random migration (at all three rpST dosages), and a decrease in IgG antibody response to tetanus toxoid at 15 d after immunization (but not at d 8, 22, or 29). Additionally, rpST treatment was associated with a decreased rate of BW gain (at 15-mg dose), increased liver and kidney weights (at all three dosage levels), and an increased incidence of renal tubular cytoplasmic vacuolation of minor severity. There were no observed differences in the overall health of the pigs due to rpST treatment, based on clinical observations as well as determination of antibody titer to, and isolation of, common swine pathogens. Therefore, there was no evidence that the observed influence of rpST treatment on immune function would be clinically relevant.     

Traumatic reticulitis in cattle: a review of 60 fatal cases

Sixty fatal cases of traumatic reticulitis in cattle were reviewed. Fifty-nine cases were caused by fragments of wire. A nail perforated the reticulum of 1 animal. Common clinical signs included decreased milk production, anorexia, fever, and weight loss. Abnormal or muffled heart sounds associated with pericarditis and epicarditis was the most common sequela, occurring in 40 cases. Fibrous adhesions found at necropsy in all cases suggest that initial clinical signs are difficult to recognize and in most cases it takes weeks to months for abnormalities to be observed.     

Comparison of liver cytology and biopsy diagnoses in dogs and cats: 56 cases

Abstract: The results of liver cytology and corresponding biopsy specimens submitted to the Pathology Department at Angell Memorial Animal Hospital during 1998 were retrospectively reviewed to objectively assess the diagnostic value of liver cytology. A "corresponding" biopsy was defined as a biopsy specimen obtained within 1 day of the cytology specimen. Fifty-six cases were reviewed, including 25 from dogs and 31 from cats. Results were in complete agreement in 34 cases, in partial agreement in 11 cases, and in disagreement in 11 cases. Agreement occurred most often in cases of fatty change (10 cases) and neoplasia (7 cases of lymphoma and 3 cases of epithelial tumor). Disagreement was most common in cases of hepatitis (6 cases) in which inflammation was not seen in cytologic specimens. Other causes for disagreement included fibrosis (2 cases), and 1 case each of amyloidosis, hemangiosarcoma, and lymphoma. Three cytologic specimens were considered suggestive of hepatitis because of leukocytosis in the background, although clinicians were advised to compare cytologic observation to CBC results. Cytologic evaluation of the liver was useful for determining disease processes, especially when disease distribution was diffuse.     

Influence of the dietary ratio between sulphur containing amino acids and lysine on performance of growing-finishing pigs fed diets with various lysine concentrations.

This study was conducted to determine the optimal ratio between sulphur containing amino acids and lysine in diets for growing-finishing pigs. Therefore, a total of five trials was carried out in which growing-finishing pigs (live weight range between 53 and 105 kg) were fed diets with various concentrations of lysine (0.62, 0.70 and 0.78%) and various ratios between sulphur containing amino acids to lysine. The diets contained 12.9 MJ ME per kg and 13.5% CP; the ratio between sulphur containing amino acids to lysine was adjusted by individual supplementation of the diets with DL-methionine. Increasing dietary levels of lysine from 0.62 to 0.78% continuously increased daily body weight gains and improved feed conversion efficiency as well as carcass characteristics. There was no significant interaction between the dietary lysine supply and the ratio between sulphur containing amino acids to lysine on animal performance parameters. This means that the effect of the ratio of sulphur containing amino acids to lysine was similar for various dietary lysine concentrations. The optimum ratio between sulphur containing amino acids to lysine according to quadratic regression analysis was 0.60, for both, growth and feed conversion. Reducing the ratio between sulphur containing amino acids to lysine from 0.59 to 0.53 and 0.47 reduced body weight by 3 and 12%, resp., and elevated the feed conversion ratio by 2 and 12%, resp. An increase of the ratio between sulphur containing amino acids to lysine from 0.59 to 0.65 failed to increase the animal performance. In contrast to animal performance parameters, optimum carcass characteristics (eye muscle area, fat area above eye muscle, meat-fat ratio and lean percentage) were achieved already at a ratio of sulphur containing amino acids to lysine of 0.53.