Influence of the administration of dried calf thymus or calf thymus extract on performance and immunity of broilers

ABSTRACT

The effect of administration of dried calf thymus [DCT] or calf thymus extract [CTE] with protein concentration 6 mg/ml was studied using 4 groups of one-day old Cobb chicks. The first group was fed on a diet contained 1% [DCT], the second group received orally 1.5 ml/bird [CTE], the birds in the third group received 0.3 ml/bird [CTE] by i.p. injection, while the fourth group was the control one. The treatments were administered daily for 20 days starting from the second day of the study. Production performance and immune parameters used were body weight, body gain feed consumption, feed efficiency, total and differential leukocytic count, total serum proteins, albumin, globulins, relative weights of thymus, bursa and spleen,% of active phagocytes in the peripheral blood, phagocytic index, HI antibody titer against NDV as well as wattle dermal testing using oil adjuvant killed NDV vaccine. Results showed that treated groups had significantly higher body weights and gain as well as better feed efficiency. The injected group had higher total leukocytic count, serum globulins and% of active phagocytes. The relative weights of bursa and thymus were significantly higher in the [DCT] group only. The obtained results augment the supposition of presence of growth factor[s] in calf thymus extract and its [their] possible involvement in modulating immunity in broilers