Main research question/goal
In the feed preparation process, leftover active components can contaminate consequent batches (“cross contamination”). To what degree is such cross contamination important for the transfer of these compounds into poultry products such as meat and eggs? Based on already known data and data obtained from the RESPOUL project, is it possible to construct a mathematical model that predicts whether (and to what degree) a veterinary drug or additive will be present in eggs or chicken meat in the event this active component was present at an undesired concentration in the chicken feed?Research approach
First, a database of chemical compounds with several physicochemical and pharmacokinetic properties is constructed. After a literature search (what experiments have already been conducted in this research area?), we conduct in vivo animal trials with both laying hens and broilers. After a 10-day (laying hens) or 14-day preparation period in which the animals receive blank feed, the animals receive experimental feed that contains a certain concentration of an active component. Afterwards, the animals are fed blank feed again during a 16-day depletion period. Based on the results obtained in the animal trials, the transfer of a molecule from the feed into several poultry matrices (muscle, liver and egg) can be determined. In addition, we look for a correlation between the residue concentrations measured and certain physicochemical and pharmacokinetic parameters. Finally, we construct a predictive mathematical model for the prediction of the transfer of a molecule into egg matrices.Relevance/Valorisation
In general, it can be stated that – depending on the active component – transfer occurs from veterinary drugs/feed additives from the feed into eggs, chicken meat and liver. The degree to which transfer occurs from the feed into animal derived products depends on the amount of the component present in the feed and the affinity of the component for each of the products. In some cases, this may lead to concentrations higher than the legally allowed concentrations. Generalizations or predictions concerning the transfer and distribution across the tissues are not possible. Mostly, a higher transfer is observed for liver compared to meat. For egg, we notice that the distribution between the yolk and the egg white cannot be predicted, but that this distribution determines the time during which the active component can be detected in the egg. For the construction of the mathematical model, some equations result from the experiments, but these need to be refined and are not yet applicable in practice. The feed industry has already made a concerted effort to avoid cross contamination, for example by adding the active component at the end of the production process, thereby avoiding contamination of the production lines. Contamination during transport or on the farm is harder to exclude.
CER - Centre d'Economie Rurale - Département Santés