1. Investigación

The infectious bursal disease (IBD) virus is one of the most resistant and prevalent virus worldwide in the poultry industry, being vaccination the main tool to control the disease. For this reason, consistent and uniform immunization of broiler flocks against IBD is necessary to avoid the disease spreading. The aim of this study was to apply and assess an epidemiologic mapping tool focused on the immunization by in ovo single broiler vaccination using an immune complex IBD vaccine. With this regard, 7,576 serum samples were collected from 603 broiler flocks raised in 354 Spanish farms. To do so, blood samples were randomly collected from birds with ages between 35 to 51 d, and the serum was analyzed by ELISA. The results obtained from this study suggested a high uniform immunization against IBDV and a protective immunization between 35 and 51 d of age, with mean titer values ranging between 6,331 and 7,426. In addition, seroprevalence titer data of this large-scale monitoring study fitted a polynomial equation with a R2 value of 0.77, helping to explain and predict the humoral response to IBD vaccination. This seroprevalence map was applied to broiler production and was based on business intelligence tool that incorporates newly developed mapping tool to cover the need of having real-time information of humoral response to IBD vaccination and could be an effective tool for veterinary services to control and prevent IBD.

The therapeutic use of bacteriophages is recognized as a viable method to control Salmonella. Microencapsulation of phages in oral dosage forms may protect phages from inherent challenges of the gastrointestinal tract in chickens. Therefore, the main objective of this study was to assess the survival of Salmonella BP FGS011 (non-encapsulated and microencapsulated) through the gastrointestinal tract under in vitro as well as in vivo conditions after oral administration to 1-day-old chicks. To this end, the phage FGS011 was encapsulated in two different pH-responsive formulations with polymers Eudragit® L100, and Eudragit® S100 using the process of spray drying. Phages encapsulated in either of the two formulations were able to survive exposure to the proventriculus-gizzard in vitro conditions whereas free phages did not. Moreover, phages formulated in polymer Eudragit® S100 would be better suited to deliver phage to the caeca in chickens. In the in vivo assay, no statistically significant differences were observed in the phage concentrations across the gastrointestinal tract for either the free phage or the encapsulated phage given to chicks. This suggested that the pH of the proventriculus/gizzard in young chicks is not sufficiently acidic to cause differential phage titre reductions, thereby allowing free phage survival in vivo.