Section 71
Chapter 70,637

Performance and Nitrogen Output in Young Broilers Fed Diets Containing different Plant By-Products and Formulated with Predetermined Ileal Digestible Amino Acid Values

Szczurek, W.

Annals of Animal Science 10(3): 285-298


ISSN/ISBN: 2300-8733
Accession: 070636288

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The aim of this study was to determine the potential for improvements in chicken growth performance and carcass traits, and reduction of N exerction via droppings by formulating diets on standardized ileal digestible amino acid (SID AA) basis. The experimental diets included 10 (starter, 1-14 day) and 15% (grower, 15-28 day) of one of 4 by-products: cold-pressed rapeseed cake (RSC1), cake from flaked/conditioned seeds (RSC2), solvent-extracted rapeseed meal (RSM) or maize distillers dried grains with solubles (DDGS), as a partial replacement for soybean meal and wheat in the control diets. The digestible AA contents of the feeds were calculated using the standardized ileal digestibility (SID) coefficients determined previously with 14-day-old birds. Diets of experimental treatments were formulated and optimized in tow versions, based on a total (T) or digestible (D) levels of Lys, Met, Cys and Thr in feed components. Feeding the T version of experimental diets had in general a significant adverse impact on chicken growth and slaughter performances in comparison with the control birds. Independently of the by-product type, mean weight gains (BWG), feed conversion ratio (FCR), and efficiency of performance index (EPI) values of chickens fed diets formulated on SID AA basis were superior to those fed diets based on a total AA. A tendency for lower daily amount of N exereted, and the significant decrease in relative N output were found on diets balanced with SID AA. Birds responded to the dietary formulation on a SID AA by increasing breast muscle (BM) yield, crude protein content of BM, and lowering abdominal fat percentage. With the exception of FCR for DDGS diet, starting chickens fed diets balanced with SID AA had growth performance similar to the control birds. Relative to the control diet, balancing digestible AA contents compensated for about half of the negative influence of total AA formulation on BWG during the grower period (DDGS and RSM diets), and on BM yield (RSC1, RSC2 and RSM diets).

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