Small Ruminant Research 116 (2014) 176–182 Contents lists available at ScienceDirect Small Ruminant Research jou rnal h om epa ge: www.elsevier.com/locate/smallrumres Long-term betacarotene supplementation positively affects serum triiodothyronine concentrations around puberty onset in female goats C.A. Meza-Herrera a,∗,1 , J.M. Reyes-Avila a , M. Tena-Sempere b , F.G. Veliz-Deras c , U. Macias-Cruz d , R. Rodriguez-Martinez c , G. Arellano-Rodriguez c a Universidad Autónoma Chapingo - Unidad Regional Universitaria de Zonas Áridas, A.P. No. 8, Bermejillo, Durango 35230, Mexico b Universidad de Córdoba, Instituto Maimonides de Investigaciones Biomédicas (IMIBIC) and CIBER Fisiopatologia de la Obestidad y Nutrición, Córdoba 14004, Spain c Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila 27054, Mexico d Universidad Autónoma de Baja California, ICA, Mexicali, BCN, Mexico a r t i c l e i n f o Article history: Received 25 May 2013 Received in revised form 12 October 2013 Accepted 16 October 2013 Available online 1 November 2013 Keywords: Goats Betacarotene Puberty Progesterone Triiodothyronine a b s t r a c t The effect of betacarotene (BC) supplementation on serum triiodothyronine (T3) levels over time in prepubertal goats was evaluated. Goats (n = 17; 3 months old; 7/8 Saanen-Alpine; 26 ◦ NL) were randomly assigned to one of the following two groups: 1) the betacarotene group, supplemented daily with 50 mg of BC (n = 9; live weight [LW]: 17.3 ± 1.0 kg; body condition score [BCS]: 3.34 ± 0.12), or 2) the control group (CC; n = 8; LW: 16.1 ± 1.0 kg; BCS = 3.17 ± 0.12). The initial mean LW (16.7 ± 1.0 kg) and BCS (3.31 ± 0.12) were similar (p > 0.05) in both groups. Whereas BC supplementation did not affect the onset of puberty (215.7 vs. 226.7 ± 6.6 days; p > 0.05) for the BC and CC, respectively, increases in serum T3 during the second half of the experiment were observed in the BC supplementation group (p < 0.05). As the LW and serum T3 levels increased, the natural photoperiod decreased, revealing a negative correlation (p < 0.05) between the variables; the observed values were r = -0.94 for LW and photoperiod and r = -0.41 for T3 and photoperiod. Long-term BC supplementation was not associated with a precocious onset or an increased percentage of goats reaching puberty. Long-term BC supplementation positively affected the release pat- tern of triiodothyronine over time, suggesting a potential role of BC as a thyroid-activating molecule; these results might possess clinical significance. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The activation of reproductive function in peripuber- tal stages and the cyclicity of reproductive capacity in adult stages are critical to the survival of a species, ∗ Corresponding author at: Galeana 585 Poniente, Colonia Centro, Lerdo, Durango 35150, Mexico. Tel.: +52 871 455 2691; fax: +52 871 455 2691. E-mail addresses: cmeza2020@hotmail.com, cmeza2000@gmail.com (C.A. Meza-Herrera). 1 http://www.researchgate.net/meza-herrera. and physiological homeostasis dictates the optimal con- ditions for reproductive success; any disturbance of this balance might affect the function of the gonadotropin releasing hormone (GnRH) neurons (Meza-Herrera, 2008, 2012; Meza-Herrera and Tena-Sempere, 2012). This transit toward complete activation of the hypothalamic- hypophyseal-gonadal (HHG) axis could be compromised by different disruptors, such as signals dictated by stress, nutritional imbalance, body weight decreases and neuro- logical alterations, which, in addition to the photoperiod, might directly influence the HHG axis through modifica- tions of the GnRH secretion pattern (Scaramuzzi et al., 0921-4488/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.smallrumres.2013.10.017