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Factors affecting variation in nutrient availability of feed ingredients for broiler chickens Open Access


Other title
Apparent metabolizable energy
Type of item
Degree grantor
University of Alberta
Author or creator
Yegani, Mojtaba
Supervisor and department
Korver, Doug (Department of Agricultural, Food, and Nutritional Science, University of Alberta)
Examining committee member and department
Scott, Tom (Department of Animal and Poultry Science, University of Saskatchewan)
Vasanthan, Thava (Department of Agricultural, Food and Nutritional Science, University of Alberta)
Oba, Masahito (Department of Agricultural, Food and Nutritional Science,, University of Alberta)
Swift, Marylou (Alberta Agriculture and Rural Development, Lacombe, Alberta)
Zijlstra, Ruurd (Department of Agricultural, Food and Nutritional Science, University of Alberta)
Department of Agricultural, Food, and Nutritional Science

Date accepted
Graduation date
Doctor of Philosophy
Degree level
Nutritive values of feedstuffs used in broiler chicken rations vary. It is important to not only reduce these variations through approaches such as using exogenous enzymes, but also to predict them accurately and rapidly. These efforts can result in formulating more balanced diets, thus allowing optimal animal performance. Corn, wheat, barley, and field pea samples were evaluated in several in vivo studies to better understand variations in their nutritive values. Several commercial enzyme products were used to determine their effects on reducing variations in energy and amino acid digestibility of corn-, wheat-, or triticale-soy diets. The effectiveness of an in vitro digestibility technique in predicting variations in AME value of wheat and triticale samples was also examined. The in vivo studies showed variations in availability of nutrients of feedstuffs. However, the extent of these variations was not the same and corn samples were less variable compared to others. Inclusion of enzymes (xylanase; xylanase, amylase, and protease; xylanase and β-glucanase) in corn-soy diets had transient effects on apparent ileal digestible energy and digestibility of crude protein and amino acid of some of the diets, although enzyme treatments had no effects on performance variables. Supplementing wheat- and triticale-soy diets with a mixture of xylanase, amylase, and protease increased the AME value of wheat and triticale samples, however, the enzyme product had small impact on reducing variations in AME value among the samples. Measuring physical characteristics did not accurately predict nutritive values of feedstuffs. Chemical characteristics were, to some extent, more relevant. The in vitro digestibility method accurately predicted AME of tested wheat and triticale samples. Addition of several chemical characteristics values into the equation increased the accuracy of prediction of the AME. However, the in vitro method was not able to predict response of a mixture of xylanase, amylase, and protease on the in vivo AME of wheat and triticale samples. Variations existed in nutritive values of wheat, barley and field pea samples. The in vitro digestibility technique can be an important step in further developments with respect to evaluation of the quality of wheat samples for broiler chickens.
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