Glicerina bruta na alimentação de frangos de corte em diferentes idades

Abstract

This study was accomplished with the objective of determine the chemical composition, the energy values and evaluate the inclusion of crude glycerin (CG) on the performance, blood parameters, carcass characteristics and quality of broiler bed. For that two metabolism trials were accomplished, where in both birds were distributed in a completely randomized design with a reference diet (0% CG) and three test diets (substitution 5, 10 and 15% of the RR per CG), totaling four treatments with five replicates, ten birds per experimental unit in the first trial and five birds in the second. In the first trial 200 male Cobb-500 broiler chicks (11-to-21 days old) were used. In the second trial, 100 male Cobb-500 broiler chicks (31-to-41 days old) were used. The trial period lasted ten days, five days of adaptation and five days of collect. Subsequently the samples of feces were dried in forced-air oven at 55°C, subjected to analysis of dry matter (DM), gross energy (GE) and nitrogen. After, the energy values by Matterson method and the Adeola were determined. The chemical composition of CG was 90.3% DM, 88.1% glycerol, 0.20% crude protein, 3,591 kcal kg-1 of GE, 3.76% methanol, 5.3% of raw mineral oil, 0.98% sodium, 0.03% potassium in the natural matter. The mean values of apparent metabolizable energy (AME), AME corrected for nitrogen balance (AMEn), metabolization coefficient of EB (CMAGE) and corrected for nitrogen balance (CMAGEn) CG, in natural matter, for the phase from 11 to 21 days by Matterson method were 2,408 kcal kg-1, 2,397 kcal kg-1, 67.06% and 66.74%, respectively. In the phase 31 to 41 days of age, were 2,479 kcal kg-1, 2,452 kcal kg-1, 69.02% and 62.24%, respectively. According to Adeola method, AMEn value estimated was 2,505 kg-1 kcal for the trial I and 2,431 kcal kg-1 for test II. In trial of performance the birds were distributed in a completely randomized design. Six treatments (GB inclusion levels: 0, 1, 3, 5, 7 and 9%) were used in the initial phase, eight replicates and 22 birds per experimental unit. In the growth phase each treatment used in the initial phase was dismembered in two treatments. For evaluation of blood parameters at 21 and 42 days old, four birds each were fasted for 6 hours, for blood brachial puncture. At 42 days old, four birds per treatment were slaughtered to determine carcass yield, breast, thigh, drumstick, wing, back, liver, gizzard and abdominal fat, determination of carcass composition and evaluation of meat quality. The inclusion of 5, 7 and 9 GB% resulted in a higher weight average end (WAE) and weight gain (WG) compared to the control at the stage of 1 to 21 days of age. The group that received CG total period (1-42 days) showed higher WAE and WG, and lower feed intake and feed conversion compared with the group receiving only CG up to 21 days old. By F test, differences were observed for cholesterol and ALT, and the group that received dietary CG to 21 showed the highest concentration compared to birds that received up to 42 days. From 1 to 21 days of age and total period (1 to 42 days), the crude glycerin can be included in the diets of broiler chickens to the level of 9%