Kohlosoma in turkeys: time matters

The flagellated protozoan parasite Cochlosoma anatis is a widespread pathogen of turkeys in the eastern United States. Infection usually results in herd heterogeneity, atrophy of lymphoid tissues, diarrhea and depression with high morbidity and relatively low herd mortality. it is assumed that the reason for the heterogeneity of the affected herds is the individual response to the infection.

Justin Lowry, a graduate student at North Carolina State University, and colleagues at North Carolina State University and the University of Georgia conducted a study to understand the impact of infection time on poult growth and uniformity. The results of the study were presented at the International Poultry Science Forum 2023.

In the study, 200 day-old poults were evenly housed in 20 isolation cages (10 per cage), 5 cages for each treatment: 0-, 7-, and 14-day challenge with uninfected controls, Lowry said.

He explained that during challenge, each bird was gavaged with approximately 500,000 C. anatis cells, except for the uninfected group, and then grown to 28 days of age. Individual body weight was recorded throughout the trial on days 0, 14, 21 and 28, and feed intake was measured on day 28.

In addition, on day 28, 2 birds per cage were orally gavaged with 4 mg/kg FITC-d and bled one hour later to evaluate intestinal permeability by blood FITC-d concentration. According to him, SAS 9.4 was used in the analysis of all data with a statistically significant p value <0.05.

Lowry noted that this study showed increased mortality associated with earlier infection, as evidenced by significantly higher mortality throughout the study among chickens infected on day 0 and day 7 compared to the uninfected group and the group infected on day 14. (P = 0.0007).

Body weight gain between all groups showed significantly lower values ​​in chickens infected on day 0 compared to those infected on days 7 and 14, with all infected poults gaining significantly lower than uninfected poults ( P = 0.0008), Lowry said. He added that there was a trend towards less uniformity associated with earlier infection times (P = 0.0648).

Overall, feed conversion rates and intestinal permeability did not change significantly in either treatment group, Lowry said.

The researchers concluded that the timing of C. anatis infection in turkey poults appears to have a major impact on growth performance. Additionally, the timing of infection may also be a contributing factor to heterogeneity in addition to individual disease effects, as growth appears to stop shortly after infection begins.