ORIGINAL ARTICLE In ovo carbohydrate supplementation modulates growth and immunity-related genes in broiler chickens S. K. Bhanja, A. Goel, N. Pandey, M. Mehra, S. Majumdar and A. B. Mandal Central Avian Research Institute, Izatnagar, UP, India Summary A study was undertaken to investigate the role of in ovo administrated carbohydrates on the expression pattern of growth and immune-related genes. In ovo injections (n = 400) were carried out on the 14th day of incubation into the yolk sac/amnion of the broiler chicken embryos. Expression of growth-related genes: chicken growth hormone (cGH), insulin-like growth factor-I & II (IGF-I & II) and mucin were studied in hepatic and jejunum tis- sues of late-term embryo and early post-hatch chicks. Expression of candidate immune genes: Interleukin-2, 6, 10 and 12 (IL-2, IL-6, IL-10 and IL-12), Tumour necrosis factor-alpha (TNF-a) and Interferon gamma (IFN-c) were studied in peripheral blood monocyte cells of in ovo-injected and control birds following antigenic stimula- tion with sheep RBC (SRBC) or mitogen concanavalin A (Con-A). Glucose injection significantly increased the expression of IGF-II gene during embryonic period and both cGH and IGF-II in early post-hatch period, while ribose-injected chicks had higher expression of IGF-II gene during embryonic stage. Enhanced mucin gene expression was also observed in fructose-injected chicks during embryonic age. Glucose-injected chicks had higher expression of IL-6 or IL-10, while those injected with fructose or ribose had higher expression of IL-2, IL- 12 and IFN gamma. It is concluded that in ovo supplementation of carbohydrates might help in improving the growth of late-term embryos and chicks. In ovo glucose could modulate humoral-related immunity, while fruc- tose or ribose might help in improving the cellular immunity in broiler chickens. Keywords in ovo injection, carbohydrates, gene expression, growth and immunity, broiler chickens Correspondence Dr. S. K. Bhanja, Principal Scientist, PHM Section, Central Avian Research Institute, Bareilly 243122, (Uttar Pradesh) India. Tel.: 91-9359105979; Fax: 91-5812301321; E-mail: subratcari@gmail.com Received: 12 July 2013; accepted: 27 March 2014 Introduction During pre- and early post-hatch period, the chicks utilize their energy reserves to meet high demand for carbohydrates. As the amount of carbohydrates in the egg is very low, gluconeogenesis from protein is the source of glucose for accumulation of glycogen that eventually fuels the hatching activities (Klasing, 1998). When energy status is limited, hatchlings may lose weight and subsequently the development of crit- ical tissues hampered. Moreover, in most of the com- mercial poultry operations, chicks get access to feed several hours after hatching. These limitations may be alleviated by administering refined carbohydrates or amino acids into the amnion or yolk sac at different days of incubation by a noble method called in ovo feeding, thus improving the chick’s liveability and growth (Bhanja et al., 2004b; Uni and Ferket, 2004). The in ovo fed nutrients help in accelerating enteric development in broilers and turkeys for greater digestive and nutrient absorptive capacity during post- hatch period (Uni and Ferket, 2004). It had already been reported that addition of glucose in drinking water suppressed gluconeogenic enzyme activity (Donaldson, 1995), thereby sparing the catabolism of useful proteins and antibodies. Studies conducted at our laboratory also revealed that glucose injection at later stage of embryonic development not only improved the broiler chick weight but also helped in the development of digestive tract (Bhanja et al., 2008a,b). Bhattacharyya et al. (2007) reported that in ovo injection of 1 ml, 10% glucose in turkey eggs on 25th day of incubation increased antisheep red blood cell (SRBC) titre (humoral immunity) and weight of bursa of fabricious at 28 days post-hatch, however, no affect was observed on cell-mediated immune response to PHAP (Phytohaemagglutinin-P). Earlier studies conducted on growth factors revealed that circulating IGF-1 and IGF-2 as well as hepatic IGF-1 mRNA expressions were regulated by Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH 1 DOI: 10.1111/jpn.12193