Níveis de energia metabolizável e lisina digestível para pintos de corte

Abstract

Two experiments were conducted to evaluate the effects of levels of metabolizable energy (ME) and digestible lysine (LD) in the pre-starter diet on broiler chicks 1-10 days and 8-21 days, about the characteristics of performance and morphometry of the intestinal mucosa of broiler chicks. In the first experiment, the objective was to evaluate the effect of levels of metabolizable energy (ME) and digestible lysine (LD), on the performance of broiler chicks 1-10 days old and intestinal morphometric characteristics. We used 1152 broiler chicks, with an average weight of 55g, distributed in a completely randomized in a 4x4 factorial, four levels of ME (2700, 2825, 2950, and 3075 kcal.kg-1) and four levels of LD (1.080, 1.187 , 1.295 and 1.403%), resulting in 16 treatments with three replications and 24 birds each. The levels of lysine and metabolizable energy acted independently in the performance of broiler chicks in the pre-start, where the energy levels exerted a linear increase (P <0.05) in final weight and weight gain, and effect quadratic (P <0.05) on feed intake and feed conversion. The levels of lysine quadratic effect (P <0.05) on the final weight, weight gain and feed conversion, and increased linearly (P <0.05) on feed intake exerted a quadratic effect. In the variable rate of deposition of protein (TDP) and fat (TDG) was not significantly influenced, however, TDG were affected linearly by increasing levels of lysine. Significant effect between levels of MS and LD on the morphometry of the intestinal mucosa (P <0.05) on the villus height of duodenum, jejunum and villous: crypt ileum. It was observed that for the pre-initial chicks level of digestible lysine for greater weight gain is 1.271% and feed conversion, 1.221%, and the level of metabolizable energy for gain weight and feed conversion is 3075 kcal.kg-1. We observed that the levels of 3075 kcal.kg-1 of 1.403% and LD yielded improved performance and morphology of the intestinal mucosa in birds in the pre-start. In the second experiment the objective was to evaluate the effect of levels of energy and digestible lysine on performance of broiler chicks 8-21 days old (early stage) and morphometry of the intestinal mucosa. We used 864 broiler chicks, with 8 days of age, with an average weight of 125g were randomly distributed in 48 pens in a 4x4 factorial design with four levels of ME (2700, 2825, 2950, and 3075 kcal.kg-1) and four levels of LD (1.080, 1.187, 1.295 and 1.403%) for a total of 16 treatments with three replicates each. The highest level of LD study (1.403%) and the highest levels (3075 kcal.kg-1) provided better results for final weight and weight gain for broilers from 8 to 21 days old. To better feed the indicated level is 3075 kcal.kg-1 to 1.080% digestible lysine. The highest levels (3,075 kcal.kg-1) and LD (1.403%) promoted better rate of protein deposition in the carcass while the higher levels of MS and LD promoted a higher rate of fat deposition in the carcass. The simultaneous increase of metabolizable energy and digestible lysine caused a linear effect (P <0.05) villus height in the duodenum, jejunum and villous: crypt ileum. The lysine levels for best performance of broiler chicks 8-21 days and morphometric characteristics is less than 1.403%. The level of 3075 kcal.kg-1 is sufficient for good performance of the bird