Prenatal tolbutamide treatment alters plasma glucose and insulin concentrations and negatively affects the postnatal performance of chickens L. Franssens a , J. Lesuisse a , Y. Wang a , B. De Ketelaere b , E. Willems a , A. Koppenol a, c , X. Guo d , J. Buyse a, * , E. Decuypere a , N. Everaert a, e a Laboratory of Livestock Physiology, Department of Biosystems, KU Leuven, Leuven 3001, Belgium b Division of MeBioS, Department of Biosystems, KU Leuven, Leuven 3001, Belgium c Animal Sciences Unit, Instituut voor Landbouw- en Visserijonderzoek, Melle 9090, Belgium d College of Animal Science and Technology, Jiangxi Agricultural University, Jiangxi 330045, China e Animal Science Unit, Gembloux Agro-Bio Tech, University of Liège, Gembloux 5030, Belgium article info Article history: Received 20 June 2014 Received in revised form 19 January 2015 Accepted 19 January 2015 Keywords: Embryonic injections Hypoglycemia Feed intake Body weight Insulin tolerance test abstract To examine the relationship of insulin and glucose, broiler embryos were subjected to acute or prolonged hypoglycemia during the late embryonic phase by, respectively, injecting once (at embryonic day [ED] 16 or 17) or on 3 consecutive days (ED 16,17, and 18) with tolbutamide (80 mg/g embryo weight), a substance that stimulates insulin secretion from the pancreas. After 1 tolbutamide injection, a prolonged (32 h) decrease of plasma glucose and a profound acute increase in plasma insulin were observed. The 3 consecutive tolbutamide injections induced hypoglycemia for 4 days (from ED 16 to ED 19). The postnatal performance after 3 consecutive tolbutamide injections in broiler embryos was also investigated. Body weight was lower in tolbutamide-treated chickens from hatch to 42 d compared with sham (P ¼ 0.001) and control (P < 0.001) chickens. Feed intake was lower in the tolbutamide group from hatch to 42 d as compared with sham (P ¼ 0.007) and control (P ¼ 0.017) animals. In addition, at 42 d, plasma glucose concentrations, after an insulin injection challenge (50 mg/kg body weight), were higher in tolbutamide-treated chickens compared with the sham and the control group as were their basal glucose levels (P value of group effect <0.001). In conclusion, tolbutamide treatment during the late embryonic development in broilers resulted in prolonged hypoglycemia in this period and negatively influenced the posthatch performance. Ó 2015 Elsevier Inc. All rights reserved. 1. Introduction In vertebrates, glucose is an essential fuel for most cells, and the transport and utilization of this substrate by these cells contribute to body glucose homeostasis in which in- sulin plays an important role. Interestingly, avian species have blood glucose levels that are twice as high as those commonly observed in mammals [1]. In addition, they have a poor responsiveness to insulin in adult life, despite the presence of normal insulin concentrations (2.02 ng/mL) [2] and the presence of a functionally conserved insulin signaling pathway [3]. In contrast to rats, the expression of some genes of the insulin signaling pathway in muscle and adipose tissue of broiler chickens did not change under experimental conditions (feed deprivation, insulin immune neutralization, and injection of exogenous insulin) [4–10]. Moreover, the major insulin-responsive glucose transporter (GLUT) 4 gene is absent in broiler chickens both during the * Corresponding author. Tel.: þ32 16 328525. E-mail address: johan.buyse@biw.kuleuven.be (J. Buyse). Contents lists available at ScienceDirect Domestic Animal Endocrinology journal homepage: www.domesticanimalendo.com 0739-7240/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.domaniend.2015.01.004 Domestic Animal Endocrinology 52 (2015) 35–42