Revista Brasileira de Zootecnia
On-line version ISSN 1806-9290
BRAZ, Nádia de Melo et al. Fiber in growth ration and its effects on performance of laying hens during the growing and laying phases. R. Bras. Zootec. [online]. 2011, vol.40, n.12, pp. 2744-2753. ISSN 1806-9290. http://dx.doi.org/10.1590/S1516-35982011001200019.
The experiment was conducted to evaluate the effects of levels of neutral detergent fiber (NDF) of diets offered to the pullets between the 7th and 17th weeks of age on performance, development of the digestive and reproductive systems, as well as the effects on sexual maturity, performance and egg quality in laying phase, which was assessed until the 35th week. A total of 1,296 pullets were distributed in a completely randomized design in a 3 × 2 factorial arrangement with four replicates of 54 birds. The levels of 14.5, 16.5 and 18.5% NDF in light and semi-heavy birds were tested. At the end of the growth phase, the birds were transferred to the laying house, keeping the same experimental design, consisting of 14 birds per plot. There was no interaction between levels of NDF and the lines on the variables. In the growth phase, increasing the level of NDF reduced the weight gain and final weight, decreased feed conversion and increased the weight of the intestines. In the laying period, the levels of NDF did not affect significantly performance, the constituents or quality of eggs. In the growth phase, the semi-heavy birds had higher feed intake, weight gain and final weight, feed conversion, bigger weight of gizzard and lower weight of liver and ovary. In the laying period, the light birds were more precocious, had lower weight and egg mass, lower feed conversion, eggs with more yolk, less albumen, higher specific gravity and lower Haugh units. Regardless of lines, the increased level of NDF in diets for growth can influence the growth performance of pullets, resulting in fewer birds without heavy influence on sexual maturity, performance or egg quality in the laying phase.
Keywords : egg quality; NDF; organ weight; semi-heavy and light laying hens.