Pathology of benzalkonium chloride toxicity and its effect on body weight gain in broiler birds.

Four groups comprising 16 broiler birds each were given benzalkonium chloride (BC) at 100, 300, 500 and 700 ppm in drinking water for 40 days and one group of 16 birds (control) was kept on plain water. Clinical signs in higher dose groups were respiratory distress, drooling of saliva, difficulty in deglutition, inappetence, apathy, lethargy and loss of body weight. Better body weight gain was recorded in 100 ppm dose rate. At 300 ppm, no significant body weight variation was recorded, whereas, at 500 and 700 ppm dose rates, significantly poor body weight gain was recorded. Major pathological changes were seen in 500 and 700 ppm groups, which exhibited formation of yellow diphtheritic plaques in the buccal cavity, swollen and pale commissures of beak and shortening of tongue. Minute necrotic and ulcerative foci were seen in oesophagus and crop. Hyperplastic and hypertrophic alterations were seen in mucosa of the upper digestive tract. Crop of 300 ppm group revealed formation of well developed epithelial nest with pseudoepitheliomatous hyperplasia at the margin of the lesion. Serum alanine transaminase, urea and uric acid in 500 and 700 ppm groups were elevated whereas no significant variations were observed in the 100 and 300 ppm groups. BC could enhance performance of broiler birds at 100 ppm dose rate. It should not be used beyond 300 ppm.

Exclusión competitiva entre Salmonella enteriditis y Salmonella gallinarum en pollito de 1 día de edad infectados simultáneamente o consecutivamente / Competitive exclusion between Salmonella enteritidis and Salmonella gallinarium in one day-old broiler chicken challenged consecutive-or simultaneously

Se evaluó la inducción a la resistencia de desafíos consecutivos o simultáneos entre Salmonella enteritidis (SE) y Salmonella gallinarum (SG). En los experimentos con desafíos consecutivos, siempre se observó que la primera variedad de Salmonella administrada, predominó casi exclusivamante en la invasión del hígado, bazo y tonsilas cecales. Cuando se administraron simultáneamente ya sea al día uno o dos, ambas variedades fueron recuperadas del hígado, bazo y tonsilas cecales. Estos resultados indican que aun cuando las aves son susceptibles a ambas infecciones de Salmonella sp (24 horas), éstas pueden ser refractarias a un segundo desafío con otra variedad, y que si ocurriera una exposición simultánea, son posibles las infecciones mixtas. Los resultados obtenidos en el presente estudio confirman y extienden informes previos de la rápida inducción a la resistencia a desafíos consecutivos con diferentes variedades de Salmonella