The Beaker: January 2014

Researchers at the University of Saskatchewan have recently completed a series of experiments investigating feeding pea to poultry.

Pea production is increasing in Western Canada and while the pea (Pisum sativum L.) is mainly produced as human food, there is the potential for surplus and feed grade pea to be used in poultry feed based on availability and price.

But how does pea perform for poultry?

 “The nutrient profile of pea is suitable for most poultry production, but it is not used to its potential because of incomplete and variable poultry nutrient data,” states PhD candidate Salaheddin Ebsim in his doctoral thesis.

In his study, entitled Establishing the Nutritional Value of Pea as Affected by Feed Processing and Pea Cultivar for Poultry, Ebsim and his supervisor, Dr. Hank Classen, were curious to clarify the nutritional value of pea in poultry diets to maximize its utilization and possibly reduce the cost of poultry production.  

“The nutritional evaluation of pea for poultry has been mostly investigated elsewhere, but under local conditions these data are not sufficient for accurate feed formulation,” writes Ebsim, noting that different pea cultivars and growing conditions may also affect the nutrient composition and availability of pea for poultry.

Starch is the main source of energy in poultry feed, and while pea seed has high starch content, the starch is different from that found in cereal grain. Pea starch is less accessible to digestive enzymes in the small intestine, making it digest slowly. In humans, this has been shown to be a good thing, but research on chickens is rare.

As Ebsim explains in his thesis, “The slowly digestible nature of pea starch has been suggested to have a unique nutritional value for poultry with evidence that the presence of slow degraded starch reduces the amino acid requirements of broilers and that a mixture of rapidly and slowly degraded starch improves broiler productivity in contrast to diets containing only rapidly digested starch.”

The three overall objectives of the research included studying the effect of various feed processing on nutrient digestibility of pea; the effect of the interaction between locally grown pea cultivar and feed processing on pea nutrient digestibility; and the impact of feeding pea to laying hens, broiler breeder hens and broilers.

Ebsim found that fine grinding and pelleting improved both pea energy and protein utilization and that this effect was much more pronounced than for classical feeds like barley, corn, and wheat cereal grains. Of note, all cultivars reacted to processing in the same way.

Using laboratory and animal testing, Ebsim further demonstrated that pea cultivar had an important impact on both the rate and extent of starch digestion and that these improvements resulted in differences in broiler performance. This suggests that cultivar selection has the potential to improve the nutritional value of pea for poultry and possibly other animals as well.  

The third objective of the thesis involved feeding pea to various classes of poultry at relatively high levels. In both broiler and laying hen trials, Ebsim found little evidence that the effect of amino acid intake on bird performance depended on the level of slow digested starch from pea. However, in all chicken classes, the production response of birds fed pea was higher than expected based on their digestible nutrient content. The reason for this response still requires clarification.

Some of Ebsim’s most interesting research came from feeding pea to broiler breeders during the brooding and rearing period. In feed restricted broiler breeders, feeding pea reduced the postprandial blood glucose level and altered bird metabolism in a way that may reduce bird hunger. Broiler breeders are most often fed every other day during the brooding and rearing period and feed nutrients are stored for a short period of time after feeding (approximately 24 hours) as fat in the liver, and then utilized until the hens are fed again. In some cases, the liver nearly doubles in weight and then returns to its initial weight during this period. When birds were fed pea, liver weight increases were less than for birds fed a more conventional diet. This research suggests that feeding pea to broiler breeders may have beneficial metabolic effects, but research is required to confirm this.

Ebsim sees increased potential to include feeds such as peas to meet future production requirements. “The use of new grain or pulse cultivars with higher nutritional value will also see increased interest, particularly those that grow well in a wide range of environments,” he states. “Pea is a good candidate for further development in this regard as it can be grown in most of places in the world.”

The research received scholarship support from the University of Tripoli, Libya, as well as support from the Saskatchewan Pulse Growers and the staff and students at the Poultry Centre, University of Saskatchewan.

This new regular series of articles is part of the communications plan of the Poultry Welfare Centre. For more information, visit the Canadian Virtual Centre for Poultry Welfare at http://poultrywelfarecentre.ca/