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  • Author or Editor: Donald E. Corrier x
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Summary

A skin test to assess T-cell mediated delayed hypersensitivity (dh) and cutaneous basophil hypersensitivity (cbh) was evaluated in the interdigital skin of young chickens. Three-day-old chickens were sensitized with Mycobacterium tuberculosis, and the dh reaction was elicited in the interdigital skin in 10-, 17-, 24-, and 31-day-old chickens by intradermal injection of tuberculin. Cutaneous basophil hypersensitivity was elicited in the interdigital skin of 10- and 14-day-old chickens by a single intradermal injection of phytohemagglutinin-P (200 μg). The effect of immunosuppression on the results of interdigital skin test for dh and for cbh was evaluated in chickens that were treated with dexamethasone daily for 4 days before testing.

The dh reaction, as indicated by a significant (P < 0.01) increase in the mean interdigital skin thickness, was detectable in 10-day-old chickens and was consistently evident in 17-, 24-, and 31-day-old chickens. The dh response in the interdigital skin of 24-day-old chickens was comparable with that elicited in the standard wattle test. The cbh reaction, as indicted by a significant increase (P < 0.005) in skin thickness, was evident in the interdigital skin of 10- and 14-day-old chickens. Treatment with dexamethasone significantly decreased (P < 0.01) the dh and cbh reactions. Results of the study indicated that the interdigital skin test may be used to evaluate normal and suppressed cell-mediated dh and cbh reactions in chickens as young as 10 and 14 days old.

Free access
in American Journal of Veterinary Research

SUMMARY

Effects of dietary aflatoxin (af) and T-2 toxin, singly and in combination, were evaluated in growing crossbred (Yorkshire × Landrace × Hampshire) pigs. The experimental design consisted of 4 treatment groups of 6 barrows each fed diets containing 0 mg of af and T-2/kg of feed (controls; group 1), 2.5 mg of af/kg of feed (group 2), 10 mg of T-2/kg of feed (group 3), or 2.5 mg of af plus 10 mg of T-2/kg of feed (af + T-2; group 4) ad libitum for 28 days (7 to 11 weeks of age). Production performance, and serum biochemical, and hematologic evaluations were made weekly. Body weight and body weight gain were depressed by all toxin treatments, but the effect of af and T-2 toxin in combination was less than additive. Liver and kidney weights, as a percentage of body weight, were increased by af treatment, and heart weight, as a percentage of body weight, was increased by T-2 treatment. Treatment with T-2 toxin induced necrotizing contact dermatitis on the snout, buccal commissures, and prepuce. Consumption of af resulted in increased serum activities of alkaline phosphatase, aspartate transaminase, cholinesterase, and γ-glutamyltransferase, and decreased serum concentrations of urea nitrogen, cholesterol, albumin, total protein, calcium, potassium, magnesium, and phosphorus. Consumption of T-2 toxin resulted in increased serum triglyceride concentration and decreased serum iron concentration. Treatment with af induced lower serum unsaturated iron-binding capacity and high rbc count, pcv, hemoglobin concentration, wbc count, and prothrombin time. Treatment with T-2 toxin induced microcytic hypochromic anemia, increased numbers of circulating metarubricytes and decreased absolute numbers of lymphocytes. Hepatocellular lesions in barrows of the af and the af plus T-2 groups (2 and 4, respectively) were compatible with aflatoxicosis. When fed in combination, each toxin appeared to have a sparing action on certain effects of the other, and the responses elicited were either additive or less than additive.

Free access
in American Journal of Veterinary Research

Summary

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, γ-glutamyltransferase, alkaline phosphatase, mean cell volume, hematocrit, and hemoglobin values, as well as lymphoblastogenesis and phagocytosis, and increased serum creatinine 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.

Free access
in American Journal of Veterinary Research

SUMMARY

Inclusion of lactose in the diets of chickens has been determined to reduce cecal colonization with Salmonella typhimurium. We hypothesized, therefore, that dietary lactose may be a practical means for reducing the prevalence of Salmonella contamination of chicken products. Because some strains of Salmonella are atypical and ferment lactose, we investigated the effects of dietary lactose on cecal colonization with lactose-fermenting S typhimurium. Broiler chicks were inoculated intracloacally with Lac+ S typhimurium selected for resistance to novobiocin and rifampicin. The chicks also were inoculated orally with certain anaerobes that do not effectively inhibit colonization by S typhimurium, but do appear essential for lactose mediated inhibition of cecal colonization. Control chicks were not given dietary lactose, and chicks in the experimental group were fed a diet containing 7% lactose. Enumeration of Lac+ S typhimurium in cecal contents revealed dietary lactose to be effective at controlling this organism. Control was correlated with changes in cecal pH and increases in undissociated volatile fatty acids, especially propionic acid.

Free access
in American Journal of Veterinary Research