The effect of feeding canola meal on concentrations of plasma amino acids.

An initial meta-analysis on isonitrogenous experiments where a protein source was replaced by canola meal (CM) showed that CM feeding increased yields of milk and milk protein and apparent N efficiency. The objective of the current study was to determine if these responses were related to increased changes in plasma AA concentrations. Although only half of the experiments of the initial meta-analysis reported concentrations of plasma AA and could be used in the current meta-analysis, lactational responses to CM feeding were similar to those reported previously. In the current meta-analysis, CM feeding increased plasma concentrations of total AA, total essential AA (EAA) and all individual EAA, but decreased concentrations of blood and milk urea-N. The current meta-analysis suggests that CM feeding increased the absorption of EAA, which would be responsible for the increased milk protein secretion and the increased apparent N efficiency.