The onset of puberty of Pelibuey male hair sheep is not delayed by the short term consumption of Morus alba or Hibiscus rosa-sinensis foliage

Abstract

The present trial evaluated the effect of phytoestrogens consumed from Mulberry (Morus alba) or Hibiscus (Hibiscus rosa-sinensis) foliage, on the onset of puberty of Pelibuey male lambs. The design of the study aimed at identifying possible acute changes on the onset of puberty. Eighteen male lambs were used (107±9 days of age, 16±3cm scrotal circumference (SC), 3.4±0.1 body condition score (BCS) and 17±1kg bodyweight (BW)). At weaning, the lambs were distributed in three groups (n=6 each): (i) Control group (balanced feed based on grains+star grass), (ii) Mulberry Group (Mulberry foliage+balanced feed) and (iii) Hibiscus Group (Hibiscus foliage+balanced feed). BW, SC and body condition score (BCS) were determined every 14 days. An estrogenized adult female was used to attempt the collection of semen samples from the males two times per week. The onset of puberty was determined as the presence of sperm showing progressive movement in the ejaculate. From then, semen collections continued in the males (once a week) until the first normal ejaculate was obtained. The nutritional value of the foliages, as well as the content of total phenols, total tannins and condensed tannins, was determined. The phytoestrogen content (Equol, 4′7-dimetoxyisoflavone, Genistein, Rutin and Ononin) was determined from the methanolic extract of both plants. Total dry matter consumptions were similar between the Control and Mulberry groups and both were higher than the Hibiscus group (P<0.05). The total consumption of phytoestrogens and tannins was similar in the Mulberry and the Hibiscus group. The short-term consumption of phytoestrogens from Mulberry or Hibiscus foliage failed to delay the onset of puberty. The mean age at the onset of puberty was similar in the three groups (146 days in the control and Mulberry groups and 154 days in the Hibiscus group; P>0.05). The mean age at the first normal ejaculate was also similar between groups (167 days for Mulberry and Hibiscus groups and 169 days in the control group; P>0.05). The BW (Control: 21.6±3.1; Mulberry: 20.7±1.9; Hibiscus: 19.8±2.8kg), the BCS and the SC were similar between groups at the onset of puberty. The present trial showed that a short exposure to M. Alba or H. rosa-sinensis foliage through diet did not influence the onset of puberty of Pelibuey male lambs.