Imagine feeding diets that improve a broiler’s feed efficiency and help
it fend off disease, all while reducing the need for commonly used
antimicrobials.
Imagine feeding diets that improve a broiler’s feed efficiency and help it fend off disease, all while reducing the need for commonly used antimicrobials. Drs. Bogdan Slominski and Gregory Blank at the University of Manitoba have discovered that a certain class of enzymes may one day help poultry producers do just that.
Common poultry diets based on corn, soybean, wheat and other plant ingredients have a number of components that are poorly digested. These “indigestibles” can make digesta in the gut thick (viscous), and can serve as a substrate for a number of harmful bacteria and other organisms that, if left unchecked, can flourish and increase the risk of disease. Drs. Bogdan Slominski and Gregory Blank are looking at the potential of a new generation of carbohydrase enzymes to break these materials down into components that: 1) are easier to digest; 2) may promote the proliferation of beneficial bacteria in the gut; and 3) may help protect poultry from Clostridium perfringens (the causative organism of necrotic enteritis (NE)).
The researchers first showed that the enzymes can breakdown soybean meal, canola meal and flax, and can decrease the viscosity of flax-based products. Early animal tests showed that when birds were fed diets without antibiotics or coccidiostats, enzyme supplementation resulted in a small increase in feed efficiency. The enzymes also slightly reduced the number of certain deleterious bacteria (Enterbacteriacea and coliforms) in the small intestine and increased the ratio of lactic acid bacteria to E. coli in the gut (it is thought that the products of enzyme activity increase acidity in the gut, making conditions more suitable to beneficial bacteria such as lactobacilli and thereby allowing them to out-compete other, deleterious bacteria such as E. coli).
More significant results were seen when birds were exposed to a strain of C. perfringens known to cause NE in commercial poultry. In this experiment, birds were fed either corn or wheat-based diets that did not contain antibiotics or coccidiostats. The addition of enzymes to the feed increased body weight of birds fed either diet at Day 40 (2.57 vs. 2.51 kg, P<0.01), decreased overall feed conversion ratio (FCR; 1.78 vs. 1.83, P<0.01), and, in those consuming wheat-based diets, reduced digesta viscosity. When the birds were challenged with C. perfringens, enzyme supplementation helped them maintain their optimal growth by improving average daily gain (59.5 vs. 56.9 g, P<0.05) in those consuming corn-based diets and FCR (1.83 vs. 1.90, P<0.05) in those consuming wheat-based diets.
In another study, birds were fed a wheat/barley/soybean/canola meal diet with or without added flaxseed (no antibiotic or coccidiostat). Addition of flaxseed reduced growth performance, but the enzymes could largely reverse these negative effects. Challenge with C. perfringens at 14 days of age initially impaired weight gain and FCR. However, during the grower phase (Days 21-37), challenged birds compensated by increasing their feed intake compared to unchallenged birds. Enzymes improved FCR during this compensatory period. Over the entire trial (0-37 days), pathogen challenge impaired FCR of birds consuming the non-flaxseed diets (1.88 vs. 1.82, P<0.05), whereas FCR improved in birds fed the flaxseed-containing diets (1.96 vs. 2.03, P<0.05). Enzyme addition significantly improved FCR of the challenged birds in both dietary groups. Neither diet nor addition of enzymes affected the incidence of lesions from NE. The enzymes did not significantly reduce mortality in the challenged birds.
The results of this research suggest that the enzymes can somewhat mitigate the negative effects of C. perfringens challenge, especially when feeding wheat-based diets. The enzymes can increase the nutritive value of diets containing flaxseed and can improve post-challenge compensatory growth in birds fed these diets.
Funding for this project was provided by CPRC, Canadian Bio-Systems Inc. and Manitoba’s Agri-Food Research and Development Initiative. It is part of a broad research program supported by CPRC and aimed at a better understanding of microbial populations in the avian gut. Researchers across Canada and abroad are working to better understand how the antimicrobials commonly used in the poultry industry really work, what populations of gut microbes are most affected by them, and what alternatives are there to their use. The results from Drs. Slominski and Blank described above contribute to the overall program and may lead to strategies to maintain broiler chicken performance with reduced need for antibiotic growth promoters.
For more details on any CPRC activities, please contact Gord Speksnijder at The Canadian Poultry Research Council, 483 Arkell Rd., R.R. #2, Guelph, Ont., N1H 6H8, phone: 289-251-2990, fax: 519-837-3584, e-mail: info@cp-rc.ca, or visit us at www.cp-rc.ca.
The membership of the CPRC consists of the Chicken Farmers of Canada, Canadian Hatching Egg Producers, Turkey Farmers of Canada, Egg Farmers of Canada and the Canadian Poultry and Egg Processors’ Council. CPRC’s mission is to address its members’ needs, which may also include societal concerns, through dynamic leadership in the creation and implementation of programs for poultry research in Canada.
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