A total of 320 13-weeks-old pullets were weighed and randomly allocated to treatments comprised by four levels of crude glycerin (0, 3, 6 or 9%) and two levels of ME (metabolizable energy, difference of 100 kcal/kg) in the diets growing (14 to 17 weeks of age), pre-lay and pre-peak (low: 2750, 2800 and 2750 kcal/kg and high: 2850, 2900 and 2850 kcal/kg, respectively). During the study, body weight was registered until 30 weeks of age, feed intake, egg weight and egg-production for each repetition and for individual hens were measured every week. The information was analyzed through a completely randomized design with a 4x2 factorial arrangement. During the growing phase, hens that received low energy diets consumed more feed (p0.05), gained less body weight (p0.05) and recorded lower feed conversion (p0.05). Besides, a positive linear effect (p0.05) was observed when including glycerin on feed conversion and weight gain. During the initial egg-laying phase, hens fed low-energy diets consumed more feed (p0.05) and laid lighter eggs (p0.05). Furthermore, a positive linear effect (p0.05) of including crude glycerin on egg yield and feed intake was observed. After the egg-laying peak, the hens of high energy groups consumed 1.6 g/d less feed (p0.05) and lay 0.9% less eggs, also, it a quadratic effect of inclusion of glycerin on laying-eggs was observed. In conclusion, the use of high energy diets decrease feed intake, increase egg weight until peak, but decrease the percentage of eggs post-peak; glycerin used in diets increases feed intake and improves egg-laying rate in different ways during the laying phase.
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