When Salmonella typhimurium and Clostridium perfringens were tested in conventional chickens, larger numbers of S typhimurium and C perfringens adhered to Eimeria tenella-infected ceca than to uninfected ceca. In germ-free chickens, S typhimurium and C perfringens adhered to the E tenella-infected cecal mucosa more than to the uninfected cecal mucosa, but fewer Bacteroides vulgatus and Bifidobacterium thermophilum adhered to the E tenella-infected ceca than to the uninfected ceca. Many bacteria adhered to the lesions caused by E tenella as observed by scanning electron microscopy. On the basis of our findings, we suggest that infection with E tenella upsets the balance of competitive adherence of bacteria, allowing more colonization of S typhimurium and C perfringens.

Atracurium besylate, a nondepolarizing neuromuscular blocking agent, was administered to 24 isoflurane-anesthetized domestic chickens. Birds were randomly assigned to 4 groups, and atracurium was administered at dosage of 0.15, 0.25, 0.35 or 0.45 mg/kg of body weight. The time of onset of twitch depression, the amount of maximal twitch depression, and the duration of muscular relaxation were recorded. After return to control twitch height, atracurium was further administered to achieve > 75% twitch depression. When twitch depression reached 75% during noninduced recovery, 0.5 mg of edrophonium/kg was administered to reverse the muscle relaxation. Throughout the experimental period, cardiovascular, arterial blood gas, and acid-base variables were monitored. The effective dosage of atracurium to result in 95% twitch depression in 50% of birds, (ED95/9595) was calculated, using probit analysis, to be 0.25 mg/kg, whereas the ED95/95 the dosage of atracurium to result in 95% twitch depression in 95% of birds, was calculated by probit analysis to be 0.46 mg/kg. The total duration of action at dosage of 0.25 mg/kg was 34.5 +/- 5.8 minutes; at the highest dosage (0.45 mg/kg), total duration increased to 47.8 +/- 10.3 minutes. The return to control twitch height was greatly hastened by administration of edrophonium. Small, but statistically significant changes in heart rate and systolic blood pressure, were associated with administration of atracurium and edrophonium. These changes would not be clinically relevant. In this study, atracurium was found to be safe and reliable for induction of muscle relaxation in isoflurane anesthetized chickens.

The B1 strain of Newcastle disease virus (NDV-B1), which is nonpathogenic for newly hatched chickens, killed embryos when it was used to inoculate chicken eggs at embryonation day 18. Treatment of NDV-B1 with an alkylating agent, ethylmethane sulfonate (EMS) markedly reduced the pathogenicity of the virus for 18-day-old chicken embryos. Eggs inoculated with the modified virus (NDV-B1-EMS) hatched, and the virus was isolated from lungs and spleen of 1-day-old chickens. The hatched chickens developed antibody to NDV and were protected against challenge exposure (at 4 weeks of age) with a highly virulent GB-Texas strain of NDV. Presence of maternal antibody to NDV in embryonating eggs did not influence the protective ability of NDV-B1-EMS, which also induced protective immunity when administered to 4-week-old chickens. The 50% protective dose of NDV-B1-EMS in maternal antibody-negative and -positive embryos was calculated to be 10.77 and 17.70 embryo 50% lethal doses, respectively. Results of the study indicated that NDV-B1-EMS may be used as an embryo vaccine to protect chickens against Newcastle disease.

The effects of 3 experimental diets that varied only in the source of dietary protein (ie, poultry, cereal, red meat) were compared in Basenjis (n = 8) with immunoproliferative enteropathy and healthy Beagles (n = 8). Significant differences in fecal character, serum IgA concentration, and intestinal digestive and absorptive function were not induced by the different sources of dietary protein. The results of this study do not support a causal role for dietary protein source in the pathogenesis of immunoproliferative enteropathy of Basenjis.

The protective effects of egg yolk powder prepared from hens vaccinated with heat-extracted antigens from K99-piliated enterotoxigenic Escherichia Coli (ETEC) strain 431 were evaluated in a colostrum-fed calf model of ETEC-induced diarrhea caused by a heterologous strain (B44). The antibody powder was obtained by spray-drying the water-soluble protein fraction of egg yolks after removing the lipid and fatty components by precipitation with hydroxypropylmethylcellulose phthalate. A total of 16 colostrum-fed calves were studied to determine whether the orally administered antibody powder would prevent fatal bovine colibacillosis caused by a virulent ETEC strain. Clinical response of individual calves was monitored and evaluated in the context of these variables: fecal consistency score, intestinal colonization, weight loss, and mortality. Control calves that were treated with vehicle (milk with egg yolk powder from nonimmunized hens) had severe diarrhea and dehydration and died within 72 hours after infection was manifested. In contrast, calves fed milk containing egg yolk powder with antipili agglutinin titers of 1:800 and 1:1,600 had transient diarrhea, 100% survival, and good body weight gain during the course of the study. Results indicate that the orally administered egg yolk powder protected against ETEC-induced diarrhea in neonatal calves and that the protective components may have been the antibodies raised by vaccination of chickens against ETEC.