Effects of in ovo feeding with glycerol for broilers
Another problem that has been observed in current broiler strains is the physiological immaturity of the avian digestive tract in the early days post‐hatching (Uni et al., 2000). Besides limiting the absorption of nutrients required for growth during the first days after hatching, the presence of undigested material in the gastrointestinal tract favours colonization by pathogens (Lan et al., 2005), increasing the incidence of diarrhoea and further compromising animal performance. One way to stimulate early development of the gastrointestinal tract is to ensure the presence of highly digestible nutrients before and immediately after hatching (Noy and Uni, 2010). This has been achieved with the use of pre‐housing nutrition (Careghi et al., 2005) or in ovo feeding (Tako et al., 2004; Grodzik et al., 2013; Yair et al., 2015).
Glycerol, or propane‐1,2,3‐triol, is an organic alcohol compound that is liquid at room temperature (25 °C), hygroscopic, odourless, viscous and has a sweet taste (IUPAC, 1993). Studies evaluating the addition of this compound to the diet of broiler chickens have confirmed an increase in bird performance and carcass yield (Silva et al., 2012). Because glycerol is the main precursor of gluconeogenesis and glycogen synthesis (Sunny and Bequette, 2011), it is assumed that the in ovo feeding of this compound may favour glycogen stores, spare amino acids for muscle growth and stimulate intestinal maturity in broiler chickens. Therefore, the objective of this study was to evaluate the effect of in ovo feeding, which is defined by administration of nutrients in the amnion for the purpose to feed the embryo, with glycerol on the development of broiler chicks after hatching.