Animal Feed Science and Technology 186 (2013) 125–129 Contents lists available at ScienceDirect Animal Feed Science and Technology journal homepage: www.elsevier.com/locate/anifeedsci Short communication Effect of copper nanoparticles on metabolic rate and development of chicken embryos L. Pineda a,1 , E. Sawosz b , K.P. Vadalasetty a , A. Chwalibog a,∗ a Department of Veterinary Clinical and Animal Sciences, Copenhagen University, Groennegaardsvej 7, DK-1870 Frederiksberg C, Denmark b Department of Animal Nutrition and Feed Science, Warsaw University of Life Sciences, Ciszewskiego 8, 02-786 Warsaw, Poland a r t i c l e i n f o Article history: Received 28 May 2013 Received in revised form 27 August 2013 Accepted 30 August 2013 Keywords: Chicken Growth promoter Metabolic rate Immunoglobulin Gene expression a b s t r a c t The objective of the study was to investigate the effects of an in ovo injection of CuNano and the timing of injection on metabolic rate (O 2 consumption and heat production, HP) and development of layer hatchlings. On day 1 of incubation, 192 fertile eggs from 29- week-old Lohmann breeder strain chickens were distributed into four groups that were administered colloidal CuNano on: day 1 and/or 10. Gaseous exchange was measured in an open-air-circuit respiration unit, and HP was calculated for 16- and 19-day-old embryos. Yolk free body weight (YFBW) at 24 h after hatching and the relative organ weights were used as a measure of hatchling development. In ovo injection of CuNano on different days during incubation significantly decreased O 2 consumption and HP compared with the con- trol group. The residual yolk sac weight in the treated groups was significantly higher than in the control group (P<0.0001), indicating that CuNano injection reduced lipid oxidation, which could be associated with the lower O 2 consumption (P=0.001). Accordingly, the organ weights (intestine, heart, liver) relative to YFBW were also lower in embryos injected with CuNano (all; P<0.05). Interestingly, the difference in metabolic rate and organ weights between treatments was not reflected in YFBW (P>0.05). Furthermore, the plasma con- centrations of IgM and IgG and the mRNA expression of NF-kB and TNF- were not affected (both; P>0.05), indicating the absence of inflammatory modulation by CuNano. These pre- liminary results demonstrated that CuNano, regardless of the day of injection, altered the metabolic rate of embryos and depressed the development of organs; however, it did not affect YFBW, immunoglobulin concentrations and the expression of immuno-related genes. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Copper is an essential trace mineral that is involved in various physiological and biochemical processes, i.e., foetal and early postnatal development, proper nerve function, connective tissue and bone development, and inflammatory processes, as well as being a constituent of several enzyme systems (ECDC, 2003). It has been shown that Cu supplementation, ca. 125 mg/kg, improves the performance of broilers and layers (Leeson, 2009; Karimi et al., 2011). However, only a small Abbreviations: CO2, carbon dioxide; CuNano, copper nanoparticles; HP, heat production; IgG, immunoglobulin G; IgM, immunoglobulin M; NF-kB, nuclear factor kappa-light-chain enhancer of activated B cells; O2, oxygen; TNF-, tumour necrosis factor alpha; YFBW, yolk-free body weight; YS, yolk-sac. ∗ Corresponding author. Tel.: +45 35333044; fax: +45 35333020. E-mail address: ach@sund.ku.dk (A. Chwalibog). 1 Permanent address: Institute of Agriculture Systems and Technology, Pampanga Agricultural College, Magalang, 2011 Pampanga, Philippines. 0377-8401/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.anifeedsci.2013.08.012