Effects of dopamine agonists and antagonists on egg laying hens

The aim of the present study is to test the effects ofdecreasing or increasing the rate of secretion of prol~qt+h onegg production in hens whose egg production declines b~low permissible profitable production. For this purpose agonists.and antagonist of the dopaminergic system were used ort th~that dopamine is considered in hens as a prolactin i~libitqry factor.Fifty hens 63 weeks old were 0 bt ained from the GelL~:Pli - Foul try C’ompan’1. Their egg yield began to decline to abouli ’I tl ~I~”’--They were devided into 5 groups of 10 birds each. ’l’he f:Lt’dt g..i’l)t,q.) was kept as control and fed the basal ration. ’I’b e se c ond 1:;~1”olq) was given a ration containing Brornocriptine. ’l’he thi:pd g:j.”cH.tp received Lisuride in the basal roffeIed a ration containing L-dopa and the fifth groration in which Reserpine was added Daily food intake and daily egg production were r~bbrdet1jIggs were individually weighed. ’l’he chemical components ofen eggs were determined weekly.At the end of 5 weeks)hens were weighed, staughtered aIdle weights of the ovaries, reproductive tracts, thyrold~ n~d.tu i taries were determined. Maximal diameter of the 1o!’gn/J!;11ic1e was measured. Serum FSH, LH and prolractin ot’ hal-lElre measured by radioimmunoassay method. ’I’he c o nt e nt e of [PUll ~and prolactin of the pituitaries of hens were aasayed by