A total of 120 Pekin ducks were distributed at random into four experimental groups, vaccinated or not against Newcastle disease (ND): G1 (Ulster 2C strain), G2 (B1 strain), G3 (LaSota strain), and G4 (nonvaccinated group). At 60 days of age, all groups were challenged with a pathogenic ND virus (NDV) suspension, and a group of specific pathogen free (SPF) chicks (G5) was also inoculated. Cloacal and tracheal swabs from all birds were collected after six, 14, 20, and 30 days post-challenge for virus isolation. NDV was isolated in 100% of SPF chicks. Pekin ducks from all groups, vaccinated or not, did not show any ND clinical signs, demonstrating that these birds are not susceptible to ND clinical disease. In the control group (G4), the virus was isolated 20 to 30 days after challenge, suggesting their possible NDV carrier state. In the vaccinated groups, no virus was isolated. This demonstrates that vaccination of white Pekin ducks against NDV is important to reduce NDV shedding in the field.

This experiment aimed at evaluating the effects of the interactions between aflatoxin (500 or 250 ppb) and ochratoxin (500 or 250 ppb), and the possible benefits of adding yeast cell wall to prevent the effects of these mycotoxins in broiler chickens. Relative organ weight gain and live performance were evaluated at 21 and 42 days of age. Results indicated that at the levels of mycotoxins included in the experimental diets, ochratoxin reduced feed intake and body weight gain, and aflatoxin only affect feed intake of 21-day-old birds. No interaction was observed between aflatoxin and ochratoxin at the levels used in experimental study. Yeast cell wall did not significantly reduced the deleterious effects of ochratoxins. No significant differences were observed in relative organ weight gain. Yeast cell wall improved feed conversion ratio when birds were fed either contaminated or non-contaminated feeds.

Esse experimento foi realizado com o objetivo de avaliar a ação de produto de exclusão competitiva (EC) sobre os efeitos da ocratoxina A (OA). As aves alimentadas com 2 ppm de OA na dieta reduziram significativamente o consumo de ração e ganho de peso, além de apresentarem pior conversão alimentar quando comparadas às aves não expostas à OA na dieta. O emprego da EC no primeiro dia de vida não minimizou esses efeitos, bem como não afetou os parâmetros zootécnicos estudados. Aves alimentadas com OA apresentaram diminuição nos títulos vacinais contra o vírus da doença de Newcastle, evidenciando-se assim a interferência dessa micotoxina na resposta imune humoral de frangos de corte. De outra forma, a EC não interferiu na resposta imune humoral de frangos de corte vacinados contra a doença de Newcastle. Tanto a AO como a EC não alteraram os dados de altura de vilo, profundidade de cripta e relação vilo:cripta nas aves aos sete dias de idade quando comparados àqueles do grupo controle na mesma idade

This experiment aimed at evaluating the action of competitive exclusion (CE) on the effects of ochratoxin A (OA). Birds fed 2ppm OA in the diet had significant lower feed intake, weight gain, and feed conversion than birds not exposed to OA in the diet. The use of CE on the first day of age did not minimize these effects nor the performance parameters studied. Birds fed OA has lower vaccinal titers of Newcastle disease virus, showing the interference of this mycotoxin on the humoral immune response of broilers. CE did not interfere in the humoral immune response of broilers vaccinated for Newcastle disease. OA and CE did not influence villus height, crypt depth, nor villus:crypt ratio in seven-day-old birds as compared to control broilers of the same age.