76 Compensatory growth following lysine restriction in grow-finish pigs: literature review and analysis

Abstract

Abstract A literature review on compensatory growth induced by lysine restriction in grow-finish pigs was conducted. First, a database was developed to standardize comparisons across the peer-reviewed literature and characterize the occurrence of compensatory growth. Publications had to include: pigs with minimum initial weight of 15 kg; a group of “non-restricted pigs” not subjected to a restriction period; a group of “restricted pigs” subjected to a restriction period induced by decreasing lysine alone, lysine and other amino acids, or crude protein in diets; a recovery period following the restriction period in which the same diet was fed to restricted and non-restricted pigs; and ad libitum feed consumption. The database included 14 publications and 57 comparisons expressed as relative differences between restricted pigs and non-restricted pigs. The database analysis categorized compensatory growth into complete, incomplete, and no compensatory growth, and characterized the patterns of restriction and recovery in each category (Table 1). The data analysis supports that compensatory growth induced by lysine restriction in grow-finish pigs occurs. The degree of lysine restriction as well as restriction and recovery duration seem critical in explaining differences between complete and incomplete compensatory growth. Also, inadequate lysine level in the recovery period seems to be associated with incomplete or no compensatory growth. Compensatory growth is more likely if: degree of lysine restriction is between 10 to 30%; lysine restriction is induced before pigs reach their maximum protein deposition; duration of lysine restriction is short and duration of recovery period is long; and lysine level in the recovery period is close to or above the estimated requirements.