-The experiment was conducted to evaluate the effects of limestone particle size and the use of artificial light for laying hens in the second laying cycle. We used 240 Hisex White laying hens at 82 weeks of age in a completely randomized design in a 5 × 2 factorial arrangement, resulting in 10 treatments with 4 replicates of 6 birds. The variables were the five particle sizes obtained by increasing the proportion of thick limestone (0, 25, 50, 75 and 100%) compared with thin limestone and two lighting programs: with and without artificial light. Limestone particle size and light did not affect performance or egg quality. However, there were changes in bird feeding schedule throughout the day as a response to the lighting program. Bone quality, density and mineral content of the tibia were not affected by the treatments, but limestone particle size had a quadratic effect of on bone deformity and strength, obtaining maximum inclusion points with 63% and 59% of thick limestone, respectively. The use of large particles of limestone in the diet and the use of a lighting program does not influence the performance and quality of the eggs of laying hens in the second production cycle, but the use of a proportion of 63.3 g of average particle size (0.60 mm) replacing the fine limestone (0.23 mm) per 100 g of total limestone added to the diet improves bone quality in these birds.

ABSTRACT. Current experiment evaluated the effects of inclusion of leucaena leaf hay (LLH) on the performance and nutrient digestibility of diets for laying hens during the growth phase (14-18 weeks). Ninety pullets (Rhode Island Red and New Hampshire) were distributed in a completely randomized design with three treatments (0%, 5% and 10% inclusion of LLH) and five replicates, with six birds. Feed intake (g bird -1 day -1 ), weight gain (g bird -1 day -1 ), feed conversion (kg kg -1 ), metabolizable energy intake (kcal bird -1 day -1 ), intake of crude protein (g bird -1 day -1 ), coefficients of dry matter (CDDM) and gross energy (CDCE), nitrogen digestibility (CDN), apparent metabolizable energy (AME) and apparent metabolizable energy corrected for nitrogen (AMEn) were evaluated. The inclusion of LLH did not statistically influence CDN, AME and AMEn of diet. However, this inclusion significantly affected CDDM and CDCE, resulting in lower CDDM and CDCE with inclusion of 10%. Whereas the use of nutrients by chicks fed on diets with the inclusion of LLH allowed the same amount of metabolizable energy, inclusion of up to 10% of LLH diet during the growth phase (14-19 weeks) of laying hens (Rhode Island Red and New Hampshire) may be recommended.Keywords: alternative food, poultry, fiber, leucaena, nutrition.Inclusão de feno da folha de leucena na ração de poedeiras na fase de crescimento RESUMO. O experimento avaliou os efeitos da inclusão do feno da folha de leucena (FFL) sobre o desempenho e digestibilidade dos nutrientes das rações para poedeiras em crescimento (14 a 18 semanas de idade). Utilizaram-se 90 frangas (Rhode Island Red e New Hampshire), distribuídas em delineamento inteiramente casualisado com três tratamentos (0%, 5% e 10% de inclusão do FFL) e cinco repetições de seis aves. Avaliou-se o consumo de ração (g ave -1 dia -1 ), o ganho de peso (g ave -1 dia -1 ), a conversão alimentar (kg kg -1 ), a ingestão de energia metabolizável (kcal ave -1 dia -1 ), a ingestão de proteína bruta (g ave -1 dia -1 ) e os coeficientes de digestibilidade da matéria seca (CDMS), da energia bruta (CDEB), do nitrogênio (CDN), energia metabolizável aparente (EMA) e energia metabolizável aparente corrigida para nitrogênio (EMAn). A inclusão de FFL não influenciou estatisticamente CDN, EMA e EMAn da ração. Entretanto, influenciou significativamente os CDMS e CDEB, resultando em menor CDMS e CDEB com inclusão de 10%. Considerando que o aproveitamento dos nutrientes da ração pelas aves alimentadas com a inclusão do FFL possibilitou o mesmo valor de energia metabolizável pode-se recomendar a inclusão de até 10% do FFL na ração de crescimento (14 a 19 semanas de idade) para poedeiras (Rhode Island Red e New Hampshire).Palavras-chave: alimento alternativo, aves, fibra, leucena, nutrição.