Digestibilidade de nutrientes de dietas de aves poedeiras na fase de cria alimentadas com aditivo simbiótico

Abstract

The objective was to determine the effect of the use of symbiotic additive on the energy and nutrient utilization of layer feed in the rearing phase. The study was conducted in the laboratory of poultry research (LAPAVE) of the Department of Animal Science of the Federal Rural University of Pernambuco, with a duration of 35 days. A total of 1040 chicks of the Dekalb White strain from 1 to 5 weeks of age were used, distributed in an entirely randomized design with 4 treatments, 10 repetitions with 26 birds each. The treatments were composed of two base diets: the first composed of corn and soybean meal, with no feed additives - RR; the second control diet composed of corn, soybean meal and meat and bone meal, with no feed additives - FCO; to formulate the third diet, 0.05% of the additive Bacitracin Zinc - Bac Zn was added to the FCO diet, and 0.1% of the symbiotic additive - Simb-C was added to the FCO diet for the fourth diet. For nutrient digestibility evaluation, the collection of excreta was performed at the 3rd week of age of the birds, following the protocol of partial collection method, in which 1% of Celite® indicator was introduced in the diets, in order to measure nutrient digestibility. The collection of excreta occurred three consecutive days, preceded by three days of adaptation to the diet with the indicator. The collected excreta were packed in plastic bags and frozen in a freezer to perform the analyses and calculations for determining nutrient digestibility (dry matter and crude protein) and gross and metabolizable energy values of the diets. Thus, three contrasts were generated, consisting of: Contrast 1: RR vs FCO; Contrast 2: FCO vs Bac Zn; Contrast 3: Bac Zn vs Simb-C. The results obtained showed that there were no significant differences between the variables CMAMS, CMAPB, CMAEB, EMA and EMAn in the contrast of the RR vs FCO diets. However, when contrasting the FCO vs. Bac Zn diets, the MCPAB was better in the diet containing the zinc bacitracin additive, which had lower values than the other variables. However, the diet containing FCO showed a better use of CMAEB, EMA and EMAn. When evaluating Bac Zn vs Simb-C no significant differences were observed between MCAPB but for the other variables the symbiotic provided lower values. It can be concluded that the symbiotic additive proved to be a possible substitute for the antibiotic zinc bacitracin in layer feed during rearing.