Evaluation of thymic lymphocyte loss of broiler using Digital Analysis of the Lymphoid Depletion System (ADDL)

The thymus is a lymphoid organ and usually evaluated for the degree of lymphocyte loss with subjective histological techniques. This study aimed to adapt and to apply of the digital analysis of the lymphoid depletion system (ADDL) in the thymus in order to obtain a more accurate analysis. Glucocorticoid was used to induce immunosuppression in 55 broilers at 21 days of age; other 15 broilers were the control group. After euthanasia of the broilers, postmortem examination was made. Both thymic chains were collected and six lobes were selected for histological examination of the degree of lymphocyte depletion (scores 1 to 5) and for submission to all stages of processing by the ADDL system. The artificial constructed neural networks (ANN) obtained 94.03% of correct classifications. In conclusion, it was possible to adopt objective criteria to evaluate thymic lymphoid depletion with the ADDL system.