New Insights on Reducing Dietary Amino Acids for Pullets


A recent study reveals that it may be feasible to reduce the dietary amino acid intake for pullets, potentially lowering costs and improving sustainability in poultry farming. This research is especially significant as modern pullets are bred to mature quickly, be highly efficient during egg production, and remain productive longer than those from previous generations. However, it raises the question: Is the industry meeting their protein needs adequately?

Traditionally, research has focused more on the amino acid requirements of laying hens during egg production, with less emphasis on pullets. Jo Ann Chew, a PhD student at the University of Alberta, highlighted this issue at the 2024 International Poultry Science Forum. In collaboration with Dr. Laura Star from Schothorst Feed Research and Aeres University of Applied Sciences, Chew aimed to determine the amino acid needs of pullets before they reach maturity.

“Understanding these requirements is crucial because pullets have a shorter growth period to reach optimal body weight and condition for egg production,” Chew explained. The study used a dose-response approach with a bent-stick model to determine these needs.

Methodology and Findings

The study involved 64 Bovans Brown and 64 Babcock White pullets from 0 to 30 weeks of age. Each bird had a radio-frequency identification tag, allowing precise feed allocation and data collection on body weight and feed intake. The research provided six isocaloric diets, and due to feeder limitations, birds were split into two groups. One group received 60%, 80%, and 100% of recommended amino acid levels, while the other group received 70%, 90%, and 110%.

Initially, all birds were given a 100% amino acid diet for the first two weeks to adapt to the feeding system. The specific dietary treatments began at two weeks and continued through 17 weeks. Photo stimulation was introduced at 17 weeks, and all birds received uniform pre-lay and layer diets from 18 weeks onward.

Key Results

The findings suggested that pullets might need less dietary lysine than current guidelines recommend. For example, the Bovans Brown pullets required 1.11% digestible lysine at five weeks of age, compared to the breeder guide’s 0.95%. For Babcock White pullets, the requirement was 0.74%, slightly above the breeder’s recommendation of 0.72%.

By 17 weeks, body weight was similar across all treatment groups. The Bovans Brown pullets needed 23.57 grams of cumulative digestible lysine, translating to 0.39% of their diet if following breeder standards, which is significantly lower than the current recommendation of 0.75%.

Implications and Future Research

Chew emphasized that while the study suggests a potential to reduce amino acid levels, the reduction should not be as dramatic as the model indicates. Lowering dietary amino acids can benefit producers by reducing feed costs and decreasing nitrogen excretion, thereby enhancing sustainability. However, further studies are needed to confirm that such reductions do not compromise egg quality and production.

“The results indicate that pullet amino acid needs are lower than current breeder guidelines suggest. Under normal conditions, there is no benefit to exceeding these levels during the pullet phase,” Chew concluded. “It is important to ensure that pullets grow well and transition smoothly into egg production while maintaining overall health and performance.”

This study opens the door to re-evaluating poultry feeding practices, potentially leading to more efficient and sustainable production methods without sacrificing bird health or productivity.