Crude Glycerin and Energy Density of Diets for Growing, Pre-Lay and Pre-Peak Backcob Brown Egg-Laying Hens
Avellaneda, YAriza-Nieto, CAfanador-Téllez, G
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 (p 0.05), gained less body weight (p 0.05) and recorded lower feed conversion (p 0.05). Besides, a positive linear effect (p 0.05) 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 (p 0.05) and laid lighter eggs (p 0.05). Furthermore, a positive linear effect (p 0.05) 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 (p 0.05) 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.(AU)
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