ISSUE FOCUS FEED & ADDITIVE MAGAZINE August 2023 29 defence mechanisms in the bird’s intestinal tract can complement good biosecurity, farm management and health practices3. Many potential interventions have been shown to work well under controlled research conditions, but how well do they perform when used in “real world” field conditions, such as those on a poultry farm? To help answer this question, Selko researchers conducted a study to evaluate the effect of two feed additive blends in field conditions. The efficacy of these blends against Salmonella prevalence in broilers was previously demonstrated under controlled conditions4. The field study took place in Brazil, a global powerhouse poultry producer and exporter, with a goal to demonstrate that multi-functional feed additive blends can reduce Salmonella incidence in broiler flocks, when used in actual field conditions. The study included 30 broiler producers from a Brazilian poultry integrator, managing a total of 39 farm locations and 86 houses. Historically, all farms used a blend of organic acids and essential oils in the feed at 1 kg/ton. An average Salmonella prevalence (assessed by collecting boot swab samples around day 21 of each cycle) of 22.7% was observed across all farms during 3 to 4 production cycles. Farms were then allocated to one of four treatments (according to a pre-determined Salmonella prevalence) and monitored during another 3 consecutive cycles. Control farms (PC – positive control) continued to use the feed additive blend (organic acids + essential oils, 1 kg/ton) without a water additive. Water farms (W) continued to use the feed additive blend in combination with a buffered organic acid blend in the Water (Selko®-pH at 0.1%). Feed farms (F) switched to a multi-functional blend of selected organic acids and ß-1-4 mannobiose (Fysal® Fit-4 at 3 kg/ton) in feed only. Water + Feed (W+F) farms switched to a combination of Selko®-pH and Fysal® Fit-4 (at the same inclusion levels as aforementioned). No other management changes were implemented. Results: The prevalence of Salmonella was different for the various treatment groups in the pre-trial phase. Farms that were later allocated to treatments W and W+F showed the highest prevalence pre-trial whereas farms allocated to treatment PC showed the lowest pre-trial Salmonella prevalence (Table 1). There was a statistically significant (P<0.05) reduction in overall Salmonella prevalence for the trial cycles observed for treatments W (-31.5%), F (-14.7%) and W+F (-16.5%), in comparison to their respective pre-trial prevalence. Overall, the groups including W and/or F reduced 20.9% the prevalence of Salmonella (Table 1). Curiously, the reduction of Salmonella prevalence for the combined W+F treatment was not as marked as compared to the indiTreatment Farms Houses Flocks Prevalence, % Pre-trial Flocks Prevalence, % Difference pvalue Trial PC W F W+F 18 4 11 6 41 9 23 13 156 36 81 48 16.4 38.9 21.7 39.6 116 27 65 39 8.6 7.4 7.0 23.1 -7.8% -31.5% -14.7% -16.5% 0.09 0.001 0.003 0.03 Table 1. Numbers of farms, houses and flocks included in the study as well as Salmonella prevalence for the pre-trial and trial periods PC (positive control – blend of organic acids and essential oils in feed at 1kg/ton), W (as PC plus buffered organic acid blend in the water [Selko®-pH at 0.1%]), F (multi-functional blend of selected organic acids and ß-1-4 mannobiose [Fysal® Fit-4 at 3 kg/ton] in feed only), W+F (combination of Selko®-pH and Fysal® Fit-4 [at the same inclusion levels as aforementioned]).
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