N. Gjorgovska, K. Filev, V. Pavlova and V. Levkov

Emir. J. Food Agric. 2014. 26 (9): 822-827 / doi: 10.9755/ejfa.v26i9.17535 / http://www.ejfa.info/

Abstract

The soy isoflavones are phytoestrogens with the same structure as the estrogen hormones of the animals, but with weaker activity. According to some authors, they influenced the growth and the body weight of small chicken. Because of this we conducted a study to establish the effect of isoflavones on the growth performances and the body weight of the light strain chicken, from hatching to 20 weeks of age. To get an answer to this aim, investigation has been made in a rearing farm. The feed in different periods was enriched with 40.88% isoflavone additive in the amount of 300, 600, 1200 and 1800 mg /kg feed. From the obtained results of the investigation it is concluded that soy isoflavones offered in different concentrations in the feed mixtures decreased the body weight of the pullets at all different ages during the experiment. The results of this investigation suggested that isoflavones supplemented to the diets did not influence the skeletal exterior indexes (Long-leggedness, Stockiness and Massiveness) of the ISA brown pullets.

Key words: Chicken, Exterior, Isoflavones, Pullets