Effects of isoflavones on testicular weight and testosterone secretion in ISA Brown roosters

Abstract

Isoflavones are phytoestrogens which have estrogen-like activity in animals and humans. Because of this characteristic influence, the aim of this investigation was to examine the effect of genistein and daidzein on testicular weight and testosterone secretion in ISA Brown roosters. Genistein and daidzein as non-steroid phytoestrogens were added in large amounts to the feed of roosters. Soy isoflavones were added to rooster diets in amounts of 0, 300, 600, 1200 and 1800 mg/kg of feed. At the end of the 37th week no significant differences were found between the groups in testicular weight (P>0.05) and testosterone secretion (P>0.05) measured in the blood of birds. Blood testosterone concentration was significantly higher in younger (20-week-old) roosters than in 37-weekold roosters (P<0.01). Genistein and daidzein present in the feed did not influence the weight of testes and no significant differences were found. Further studies are required to investigate the effect of isoflavones on other androgenic characteristics.

Effects of dietary soy isoflavones on growth, antioxidant status, immune response and resistance of juvenile grass carp ( Ctenopharyngodon idella ) to Aeromonas hydrophila challenge

“…Isoflavones are well known to exert several oestrogen-like biological effects on animals because of the similarity of their structure to the natural oestrogen structure (Gjorgovska & Filev, 2013). In mammals, many studies have shown that isoflavones have a broad range of regulatory effects, such as antitumour effects, antioxidant effects and immune system regulation (Masilamani, Wei, & Sampson, 2012).…”

Effects of soy isoflavones on intake, body weight, sex hormones, antioxidant performance, and semen quality in Xinong Saanen goats

“…In our study we did not observe any changes in testosterone concentration as a result of SI supplementation. Other studies also reported no effects of SI on testosterone concentrations in roosters (Gjorgovska and Filev 2013) and rabbits (Yousef et al 2003;Yousef et al 2004). A seasonal variation in reproductive performance can be observed in goats, which accompanied the changes in hormone secretion.…”