Wheat amino acid digestibility differed across pullet ages

What the study found: The study found that standardized ileal amino acid digestibility (the proportion of amino acids digested and absorbed before the end of the small intestine) varied among 10 wheat samples and could be predicted from wheat chemical properties. The authors report that prediction equations were developed for pullets during both brooding and growing periods.
Why the authors say this matters: The authors state that wheat is a major alternative to corn in layer diets, and that better assessment and prediction models for amino acid digestibility could support more precise feed formulation. They conclude that these equations may provide a rapid and accurate way to evaluate the amino acid nutritional value of wheat in pullets.
What the researchers tested: The researchers evaluated physical properties, conventional nutritional components, amino acid profiles, and standardized ileal amino acid digestibility of 10 wheat samples from different sources. They fed the samples to Jingfen No. 8 pullets during brooding (days 28-31) and growing (days 92-95), using 11 dietary groups, including a nitrogen-free diet and test diets with wheat as the sole amino acid source.
What worked and what didn't: The chemical components of the wheat samples varied considerably, with coefficients of variation above 10% for ether extract, crude fiber, neutral detergent fiber, calcium, and total phosphorus. The standardized ileal digestibility values of the 15 analyzed amino acids differed significantly among the 10 wheat samples, and the best-fitting prediction differed by period: the serine equation had the best fit during brooding (R² = 0.869), while four equations in the growing period had R² values above 0.80.
What to keep in mind: The abstract does not describe limitations beyond noting that the assessment and predictive models had not been fully established before this study. The summary is limited to the 10 wheat samples, the Jingfen No. 8 pullets tested, and the brooding and growing periods studied.

Key points

• Standardized ileal amino acid digestibility differed significantly among 10 wheat samples.
• Chemical properties of wheat were linked to digestibility during both brooding and growing periods.
• The best brooding-period model was the serine equation, with R² = 0.869.
• Four growing-period prediction equations had R² values above 0.80.
• The study used Jingfen No. 8 pullets and tested both a nitrogen-free diet and wheat-based test diets.