Published in Scientific Works. Series C. Veterinary Medicine, Vol. LXXI, Issue 2
Written by Ivona Maria ZĂBAVĂ, Tudor Andrei KACENCO, Nicolae DOJANĂ
The selection process led to changes in the pituitary-ovarian axis control in egg-laying chicken hybrids. This paper investigates the particularities of the control exercised by the pituitary-ovarian axis on reproductive function in Lohmann and Leghorn egg-laying selected hybrids versus the Sussex breed. The blood level of follicle-stimulating hormone (FSH) of the hybrids was higher than that of Sussex hens in the first part of the laying cycle, falling below that of Sussex hens in the second part of the cycle. The concentration of LH showed a peak in all categories of hens, the values in hybrid hens being consistently higher than those of Sussex hens (P<0.05). The analysed hybrids showed particularities of the ovarian endo-secretor response, characterized by a higher oestrogen secretory peak at the beginning of laying and a higher secretory level in hybrids compared to Sussex hens (P<0.05), throughout the laying cycle. Both FSH and LH concentrations were positively correlated with laying frequency, the correlative values being higher for LH. Correlations of laying frequency and ovary weight/body weight ratio were also identified.
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