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Administration of ochratoxin A and T-2 toxin to growing swine.
1994
Harvey R.B. | Kubena L.F. | Elissalde M.H. | Rottinghaus G.E. | Corrier D.E.
Effects of dietary ochratoxin A (OA) and T-2 toxin, fed singly and in combination, were evaluated in growing crossbred pigs. Thirty-six barrows (3 replicates of 3 for each of 4 treatment groups, mean body weight, 18.0 kg) were fed: 0 mg of OA and 0 mg of T-2/kg of feed (control); 2.5 mg of OA/kg of feed; 8.0 mg of T-2/kg of feed; or 2.5 mg of OA plus 8.0 mg of T-2/kg of feed for 30 days. Production performance, serum biochemical, hematologic, immunologic, and pathologic evaluations were made. Body weight and body weight gain were decreased by all toxin treatments, but the combination toxin treatment reduced weight gain more than did either of the toxins administered singly and could be considered additive. Liver weight was decreased by combination treatment, whereas kidney weight was increased by OA treatment. Ochratoxin decreased serum cholesterol, inorganic phosphorus, and alkaline phosphatase values; reduced mean cell volume, hemoglobin concentration, and macrophage phagocytosis; and increased creatinine and total protein values. Consumption of T-2 toxin reduced hemoglobin and serum alkaline phosphatase values. The combination treatment decreased serum cholesterol, gamma-glutamyltransferase, alkaline phosphatase, mean cell volume, hematocrit, and hemoglobin values, as well as lymphoblastogenesis and phagocytosis, and increased serum nine concentration. We concluded that OA and T-2, singly or in combination, can affect clinical performance, serum biochemical, hematologic, and immunologic values, and organ weights of growing barrows. Although some analytes were affected more by the combination than by either toxin alone, the interactions could best be described as additive, not synergistic.
Afficher plus [+] Moins [-]Intranasal administration of Pasteurella multocida toxin in a challenge-exposure model used to induce subclinical signs of atrophic rhinitis in pigs.
1994
Diemen P.M. van | Jong M.F. de | Vries Reilingh G. de | Hel P. van der | Schrama J.W.
A challenge-exposure model was developed for dose-dependent induction of subclinical (moderate) atrophic rhinitis (AR) in conventionally raised Dutch Landrace and Large White pigs, about 4 weeks old. Under favorable climatic and housing conditions, pigs were intranasally challenge-exposed with Pasteurella multocida-derived toxin (Pm-T) 3 days after pretreatment by inoculation with 1% acetic acid. Pigs were challenge-exposed with 1 of the following Pm-T doses: 0 (control), 5, 13, 20, or 40 microgram of Pm-T/ml of phosphate-buffered saline solution (PBSS), 0.5 ml/ nostril/d on 3 consecutive days. Five weeks after challenge exposure, subclinical moderate) AR status was defined as intermediate conchal atrophy (grade 2 for ventral conchae on a 0 to 4 scale and grade 1 or 2 for dorsal conchae on a 0 to 3 scale, respectively) and perceptible difference in change in brachygnathia superior (CBS) between control and challenge-exposed pigs between the beginning and end of the study. All Pm-T-exposed pigs had nasal damage that was dose-dependent. The higher Pm-T doses resulted in higher ventral conchae atrophy and dorsal conchae atrophy scores. The CBS increased with applied Pm-T dose, resulting in significant (P < 0.05) differences between controls (3.88 mm) and the 13-, 20-, and 40-microgram Pm-T-treated groups (7.77, 6.58, and 7.98 mm, respectively). In response to the applied dose, weight gain per week for Pm-T-exposed pigs was lower than that of controls after week 3 (P < 0.01). Difference from controls was 32, 54, 52, and 96 g/d/pig for 5-, 13-, 20-, and 40-microgram Pm-T-treated groups respectively, in the last 2 weeks. For Dutch Landrace and Large White pigs, intranasally administered Pm-T mimicked the pathogenic effect of in vivo infection with toxigenic Pm strains. The optimal model to induce subclinical AR appeared to be 13 microgram of Pm-T/ml (0.5 ml/nostril/d) on 3 consecutive days.
Afficher plus [+] Moins [-]Restriction endonuclease analysis of a porcine isolate of bovine herpesvirus type I.
1994
Varady E. | Tuboly T. | Derbyshire J.B.
Persistence of immunity to toxoplasmosis in pigs vaccinated with a nonpersistent strain of Toxoplasma gondii
1994
Dubey, J.P. | Baker, D.G. | Davis, S.W. | Urban, J.F. Jr | Shen, S.K.
Persistence of the vaccine RH strain of Toxoplasma gondii was studied by bioassay and histologically in 14 pigs. Pigs were euthanatized 2, 4, 7, 8, 14, 15, 21, 29, 36, 42, 52, 57, and 76 days after IM inoculation with 100,000 T gondii tachyzoites. Viable T gondii tachyzoites derived from the RH strain were isolated by bioassay in mice inoculated with tissues of pigs euthanatized up to 14 days after vaccination. Except for fever, pigs vaccinated IM with the RH strain remained clinically normal. Two other pigs inoculated IV with 100,000 T gondii tachyzoites of the RH strain became ill, and 1 pig was comatose by 4 days after inoculation. These findings indicate that route of inoculation may influence the response of pigs to T gondii. To evaluate protective immunity in pigs vaccinated with the RH strain, 16 age-matched pigs were allotted to 4 groups (A-D) of 4 pigs each. Eight pigs (groups A and C) were vaccinated IM with 100,000 RH strain tachyzoites and 8 pigs (groups B and D) were nonvaccinated controls. Pigs of groups A and C were challenge-inoculated orally with a lethal dose of T gondii oocysts (100,000 oocysts) 81 days after vaccination, pigs of groups B and D were inoculated similarly 220 days after vaccination. The concentration of T gondii at 3 days after challenge inoculation of pigs vaccinated 81 days earlier was reduced 100,000-fold in mesenteric lymph nodes, compared with that in a nonvaccinated pig euthanatized at 3 days after challenge inoculation. Another nonvaccinated pig became comatose and had to be euthanatized at 7 days after challenge inoculation, numerous tachyzoites were in its mesenteric lymph nodes, intestines, and liver. The vaccinated pigs generally remained clinically after challenge inoculation with oocysts. Toxoplasma gondii was not isolated by bioassays from tissues of 5 of 8 vaccinated pigs, but was recovered from all nonvaccinated pigs. Results indicate that protective immunity persisted in pigs for at least 7 months after vaccination with the nonpersistent RH strain of T gondii.
Afficher plus [+] Moins [-]Use of polymerase chain reaction to detect porcine parvovirus associated with swine embryos
1994
Gradil, C.M. | Harding, M.J. | Lewis, K.
The role of porcine parvovirus (PPV) in inducing reproductive failure in swine has been extensively documented. However, information is not available as to the risk of ppv transmission by embryo transfer. Using the polymerase chain reaction (PCR) technique, PPV-specific DNA was detected in association with 4-day-old porcine embryos incubated in vitro in the presence of NADL-8 strain of PPV, despite attempts to rid the embryos of virus by either washing or treatment with pronase or trypsin. The presence of PPV in embryos collected from acutely infected swine was not detected by PCR, although PPV DNA was detected in the proximal portion of the reproductive tract during the early stages of infection. Viral-specific nucleic acid was not detected in embryos transferred from infected donors to seronegative recipients and retrieved and assayed on the 15th and 32nd days of gestation. Results of the use of PCR to detect PPV associated with swine female reproductive tract and embryos ascribe minimal risk to the transmission of PPV to seronegative recipients through embryo transfer.
Afficher plus [+] Moins [-]Effect of mimicking prepartum concentration of estradiol-17 beta on the inflammatory response to endotoxin in gilts
1994
Magnusson, U. | Holst, H. | Kindahl, H. | Karlsson, A.
The effect of mimicking prepartum concentration of estradiol-17 beta on the inflammatory response to endotoxin in gilts was studied. The study was performed in a split-litter design and comprised 5 pairs of littermates. A catheter was inserted into the jugular vein 2 days prior to the start of the study. In each pair, 1 littermate was treated IM with 2.5 mg of estradiol-17 beta/75 kg of body weight, and the other littermate was given peanut oil IM as a control. The day after treatment, all gilts were challenge-exposed with a Salmonella typhimurium-derived endotoxin (1 microgram/kg, IV) and the inflammatory response to challenge exposure was monitored. There was no effect of estradiol treatment on the transient clinical signs of endotoxemia or on the increase in rectal temperature. The increase in blood concentrations of prostaglandin F2 alpha, metabolite and cortisol after endotoxin challenge exposure was not affected by estradiol. Decrease in number of circulating blood mononuclear cells and polymorphonuclear leukocytes was not changed by estradiol treatment. Taken together, mimicking prepartum concentration of estradiol did not affect either the magnitude or the kinetics of the inflammatory response to endotoxin in gilts. Relevance of these findings to development of endotoxin-mediated diseases, such as the postpartum agalactia syndrome, needs further study.
Afficher plus [+] Moins [-]Lymphocyte proliferation responses of pigs inoculated with transmissible gastroenteritis virus or porcine respiratory coronavirus
1994
Brim, T.A. | VanCott, J.L. | Lunney, J.K. | Saif, L.J.
Cell-mediated immunity was evaluated in intestinal, respiratory, and systemic lymphoid tissues of pigs exposed when 11 days old to virulent transmissible gastroenteritis virus (TGEV), attenuated TGEV, or porcine respiratory coronavirus (PRCV), 3 antigenically related porcine coronaviruses with distinct enteric and respiratory tissue tropisms. Mononuclear cells were prepared from mesenteric lymph nodes (MLN), bronchial lymph nodes (BLN), and spleens of pigs and tested for virus-specific responses by use of lymphocyte proliferation assays. Vigorous MLN and BLN proliferation responses to virulent TGEV and PRCV, respectively, at postinoculation days 8 to 24 were strongly associated with prior detection of TGEV in rectal swab samples and PRCV in nasal swab samples. Gastrointestinal disease and intestinal virus replication, assessed on the basis of rectal virus shedding, were almost exclusively found in the virulent TGEV-inoculated pigs, even though virulent TGEV and a high dose of attenuated TGEV elicited the highest proliferation responses in MLN. Pigs exposed to PRCV or attenuated TGEV did not have clinical signs of disease, and only 1 pig given a high dose of attenuated TGEV shed virus in feces. Porcine respiratory coronavirus replicated in the respiratory tract after either oronasal or aerosol inoculation of virus and induced strong BLN, but not MLN, proliferation responses. A high dose of attenuated TGEV (4 X 10(8) plaque-forming units) was more effective than a lower dose of attenuated TGEV (7 X 10(6) plaque-forming units) in eliciting significant lymphocyte proliferation in MLN and BLN. Cellular immune function, assessed on the basis of mitogen-induced proliferation of lymphocytes, was comparable for all 3 sources of lymphocytes and was not adversely affected by exposure to any of the pigs. The tissue tropism of TGEV and PRCV was associated with induction of virus-specific cell-mediated immune responses, as evidenced by substantial lymphocyte proliferation responses in MLN and BLN, mucosa-associated lymph nodes adjacent to the primary sites of virus replication. The failure of PRCV strain ISU-1 to replicate in the intestinal tract correlated with poor virus-specific cellular immune responses in MLN.
Afficher plus [+] Moins [-]Administration of ochratoxin A and T-2 toxin to growing swine
1994
Harvey, R.B. | Kubena, L.F. | Elissalde, M.H. | Rottinghaus, G.E. | Corrier, D.E.
Effects of dietary ochratoxin A (OA) and T-2 toxin, fed singly and in combination, were evaluated in growing crossbred pigs. Thirty-six barrows (3 replicates of 3 for each of 4 treatment groups, mean body weight, 18.0 kg) were fed: 0 mg of OA and 0 mg of T-2/kg of feed (control); 2.5 mg of OA/kg of feed; 8.0 mg of T-2/kg of feed; or 2.5 mg of OA plus 8.0 mg of T-2/kg of feed for 30 days. Production performance, serum biochemical, hematologic, immunologic, and pathologic evaluations were made. Body weight and body weight gain were decreased by all toxin treatments, but the combination toxin treatment reduced weight gain more than did either of the toxins administered singly and could be considered additive. Liver weight was decreased by combination treatment, whereas kidney weight was increased by OA treatment. Ochratoxin decreased serum cholesterol, inorganic phosphorus, and alkaline phosphatase values; reduced mean cell volume, hemoglobin concentration, and macrophage phagocytosis; and increased creatinine and total protein values. Consumption of T-2 toxin reduced hemoglobin and serum alkaline phosphatase values. The combination treatment decreased serum cholesterol, gamma-glutamyltransferase, alkaline phosphatase, mean cell volume, hematocrit, and hemoglobin values, as well as lymphoblastogenesis and phagocytosis, and increased serum nine concentration. We concluded that OA and T-2, singly or in combination, can affect clinical performance, serum biochemical, hematologic, and immunologic values, and organ weights of growing barrows. Although some analytes were affected more by the combination than by either toxin alone, the interactions could best be described as additive, not synergistic.
Afficher plus [+] Moins [-]Evaluation of quantitative acid-base balance and determination of unidentified anions in swine
1994
Frischmeryer, K.J. | Moon, P.F.
Arterial blood samples were collected from 19 anesthetized pigs before and after hemorrhage was induced. Blood gas tensions and concentrations of sodium, potassium, chloride, lactate, and total protein were measured. Results indicated that hydrogen ion (H+) concentration calculated from a specific formula was a biased and imprecise estimate of measured H+ concentration. The bias was 5.45 nEq/L, with limits of agreement from -7.92 to 18.83 nEq/L. Because albumin is the fraction of plasma protein most important in acid-base balance, the agreement between predicted and measured H+ concentration was reevaluated, using an albumin charge estimate and a reference swine albumin-to-globulin ratio. This improved the ability of the formula to predict H+ concentration; the bias decreased to 1.33 nEq/L with limits of agreement from -12.16 to 9.49 nEq/L. The formula and a simplified approach for clinical application were biased and unacceptably imprecise estimators of lactate (L-) concentration. The formula approach underestimated L- concentration by 2.8 (-12.4, 6.7) mEq/L, whereas the simplified method overestimated L- concentration by 5.0 (-3.8, 13.9) mEq/L.
Afficher plus [+] Moins [-]Relation between body temperature and dexmedetomidine-induced minimum alveolar concentration and respiratory changes in isoflurane-anesthetized miniature swine
1994
Vainio, O.M. | Bloor, B.C.
Dexmedetomidine (Dex), an alpha 2-receptor agonist, is the pharmacologically active d-isomer of medetomidine, a compound used as a sedative in veterinary medicine. Isoflurane anesthetic requirement (minimum alveolar concentration; MAC), rectal temperature, and cardiorespiratory variables were studied in chronically instrumented Yucatan miniature swine during DEX (20 micrograms/kg of body weight)-induced changes in body temperature. All studies were performed at room temperature of 22 C. The DEX was given as a 2-minute infusion into the left atrium. Each pig was studied twice. For protocol 1, the core temperature of the pigs was maintained at (mean +/- SD) 38.2 +/- 0.5 C by use of a thermostatically controlled water blanket and a heating lamp. For protocol 2, the core temperature was not externally manipulated and it decreased from 38.2 +/- 0.4 C to 32.2 +/- 1.2 C during the more than 3 hours of the protocol. Control isoflurane MAC was 1.66 +/- 0.2% and was 1.74 +/- 0.3% for protocols 1 and 2, respectively; DEX decreased MAC by 34 and 44%, respectively. For protocol 1, reduction in MAC after DEX administration returned by 50 and 80% at 84 and 138 minutes, respectively. If rectal temperature was not maintained (eg, allowed to decrease), MAC was reduced by 57% at the same time as the return to 80% in the swine with maintained body temperature. Respiratory rate and minute ventilation were significantly higher in swine with maintained temperature. The PaCO2 was lower and, accordingly, pH was higher in these swine. Blood pressure and heart rate were not affected by temperature changes.
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