ARTICLE FEED & ADDITIVE MAGAZINE December 2023 71 Prior to infection, no birds were infected with Salmonella. Post-infection, 63% and 38% of the birds in the NC group were infected at day 21 and day 35, respectively. The number of Salmonella positive samples was reduced by half at both time points for the animals from the NQ group. From the birds that were positive at day 21, one part naturally recovered from the infection (“previously positive”). The recovery rate is similar in both treatment group (~60%). From the birds positive at day 35, a part was already positive at day 21 and a part turned positive between day 21 and day 35 (“new positive”). The NQ group had much less ‘new positive’ than the NC group, which indicates a stronger support against Salmonella, not only shortly after the infection but during the whole production cycle. Overall, there were fewer birds ever infected with Salmonella for the NQ group (33% total infection rate vs 75%) and, at day 35, there were much fewer positive birds in the NQ group than in the control (16% vs 38%). In parallel, scientists measured the immune response via the concentration of Salmonella IgA in blood. Prior to infection, the base level of IgA was around 15ng/ml in both treatment groups. At day 21, the blood IgA concentration increased to about 40 ng/ml in the NC group, showing the immune response of the birds to the Salmonella infection. Birds from the NQ group had 11% more blood IgA at day 21 than birds from the NC group, which indicates a better immune response. Finally, scientists measured the impact of both treatments on performance. The birds from the NQ group had a 1-point Figure 1. Double-Encapsulation Technology
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