Standardized amino acids digestibility of wheat distillers dried grains with solubles in force-fed roosters

COZANNET, Pierre; PRIMOT, Yvan; GADY, Cecile; METAYER, Jean-Paul; LESSIRE, Michel; SKIBA, Fabien; NOBLET, Jean

Standardized amino acids digestibility of wheat distillers dried grains with solubles in force-fed roosters

2011

In recent years, policies encouraging the production of ethanol from maize or wheat have stimulated an increased production of distillers dried grains with solubles (DDGS) whose nutritional value for poultry is poorly described, especially for wheat DDGS. Seventeen wheat DDGS samples were obtained from 7 plants in Europe from June to September 2007. Each sample was analysed for chemical composition and 10 representative samples were measured for amino acids (AA) content and their standardized digestibility (SDD) in caecectomized roosters. Lightness score (L) of each DDGS was also measured. Results indicated a rather stable crude protein (CP; N x 6.25) content (327 to 392 g/kg DM; average: 364 g/kg DM) but the AA profile was rather variable between samples. Lysine (lys) was the most affected AA with contents ranging between 0.83 and 3.01 g/100g CP. In addition, only 0.76 of total lys were free if estimated by the fluoro dinitro benzene procedure and 0.85 of total lys were free if estimated by the furosine procedure. The SDD of lys was also highly variable (-0.04 to 0.71) with the lowest values observed for DDGS samples with a low lys content in CP; these latter samples had also a high occurrence of Maillard reactions and low L values (< 50). Consequently, both lys content in CP (r = 0.63) and SDD of lys (r = 0.64) values were positively related with L. Our data indicate that lys SDD can be accurately predicted from lys content in CP according to a quadratic (R² = 0.94) or a linear-plateau model (R²= 0.90; breakpoint for 1.9 g/100g lysine in CP and a 68% plateau SDD value).

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