. The effect of L-glutamate supplementation of male goats upon the variables body weight (BW), body condition score (BCS), scrotal circumference (SC) and serum levels of insulin-like growth factor-1 (IGF-1) under a natural increased photoperiod was evaluated. The study was carried out at the Southern Goat Research Unit (URUZA-UACh, 25° NL, 103° WL, 1,117 m) during March. Alpine bucks (n=6, 24 months. BW=49.83±0.33 kg), received free access to a basal diet of alfalfa hay (14% CP; 1.14Mcal kg-1 NEm) and corn silage (8.1% CP; 1.62 Mcal kg-1 NEm). Bucks were randomly assigned to one experimental group: i). L-glutamate group (GLUT n=3; PV = 50.3±0.33 kg, CC= 3.25±0.11 units) and ii). Control group (CONT, n=3; PV = PV=49.3±0.33 kg, 3.40±0.04 units). While BW (49.83±0.33 kg), BCS (3.20±0.11 units) and SC (24.21±0.77 cm) did not differ (P>0.05) between treatments, both the serum IGF-1 level concentration (408.44 vs 309.00 mL-1) as well as the secretion pattern of IGF-1 across time differed (Pd”0.05) between treatments, favoring to the GLUT supplemented bucks. Glutamate supplementation positively affected the synthesis and secretion pattern of IGF-1 under a photic scheme considered as inhibitory of reproductive function. The last could be both of biologic and economic significance particularly in goat production systems under semi-extensive and intensive conditions using genetic groups with a high upgraded level towards seasonal-dairy breeds.

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