The effect of oregano essential oil on Feed Passage Syndrome in broilers: 1. Assessment under field conditions

Feed Passage Syndrome (FPS) is a prevalent condition that includes wet excreta, with undigested feed, and loss of feed efficiency, with multiple predisposing factors involved. Alternatives to antimicrobials, including phytogenics, are being studied to control this process. This study aimed to assess oregano essential oil (OEO) in broilers subjected to a natural field FPS challenge. Four broiler houses (two males; two females) presenting FPS were divided into two groups per house and assigned to a control or OEO-treated group through drinking water for five days. The FPS was characterized by >30% wet droppings, >50% with undigested feed, <5% with desquamated mucosa, >10% birds with enteritis, and 90% with undigested feed in the lower ileum, and flocks clinically positive for dysbacteriosis. After a five-day treatment, OEO-treated birds showed fewer abnormal droppings (P < 0.05), reduced the prevalence of dysbacteriosis (P = 0.0404), and a progressively recovering BW. The OEO treatment showed to influence the Gompertz growth curve parameters (growth rate, P = 0.0165; inflection point, P = 0.0359), potentially reducing the age at the target market weight in 0.8 days. In conclusion, the results indicate that the OEO treatment in drinking water for broilers naturally challenged with the Feed Passage Syndrome may improve excreta characteristics and attenuate the negative impact of the syndrome on the BW.