engleski

Competitive exclusion against Salmonella enterica subspecies enterica serovar Enteritidis infection in chickens

Altogether 250 newly hatched broiler chickens allocated to two groups were used and two replicate trials were carried out. The chicks were dosed by gavage with commercial competitive exclusion (CE) product (trial groups) or with 0.5 ml of physiological saline (controls) at day 0, day 1 and day 5. On day 2, eight birds per tier were challenged by oral gavage with 0.5 ml of an approximate 107 organism/ml dilution of S. Enteritidis phage type 9a and were used as seeders. On the fifth day after challenge, and at 14 and 21 days of age, 12 chicks from each group were selected and Salmonellae were counted in their caecae. On days 14 and 21, the proportion of infected animals was significantly lower (p < 0.05) in the group treated with CE product than in the challenge controls. One half of the treated animals remained infected on day 14, and only one-quarter a week later. In the control group, the proportion of infected animals reached 21/24 and 17/24 on days 14 and 21, respectively. There was no significant difference (p>0.1) among treated groups regarding the spleen colonization observed on days 14 and 21. On day 14, the number of chickens with infected spleen was 4/24 in challenge control and 9/24 in the treated group. On day 21, this proportion was 4/24 and 3/24, respectively. Commercial competitive exclusion product provided a significant protective effect against pathogenic S. Enteritidis PT 9a used for challenge.

S. Enteritidis; competitive exclusion; chicken; salmonellosis

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