Thyrotrophic [TSH], thyroxine [T4], triiodothyromine [T3] and some other blood and egg parameters as affected by administration of antiadrenergic agent [reserpine] into Fayoumi laying hens

ABSTRACT

The present study was undertaken to clarify the effect of reserpine on thyroid gl and activity and persistency of egg production besides some other blood and egg parameters at later stages of egg production. Therefore, 50 Fayoumi layers 63 weeks of age were used. The birds were allocated into five equal groups. One kept as control, while the others received different gradient doses of reserpine for nine successive weeks. The results showed that reserpine led to a decrease in serum T4 in all treated groups, while T3 was decreased in two treated groups. TSH was increased in two groups offered reserpine at rate of 3 mg and 6 mg/15 kg feed. Serum cholesterol was increased in three of the treated groups, while total lipids concentration was increased in two of the reserpine treated groups. Reserpine in small doses daily or every other day led to an increase in egg production with a consequent increase in persistency of productivity than that of the controls but it led to a decrease in shell thickness. Thus, it is concluded that reserpine in small doses may modulate the other factors involved in egg production to increase productivity even in slight decrease of thyroid hormones. It is also recommended the use of reserpine in small dose 1.5 mg/15 kg feed day after day to increase egg production for table purposes at the alter stages of flock productivity