The effect of frequency of feeding on the response by growing pigs to supplements of free lysine.

1. Six experiments, involving a total of 320 pigs, were conducted to examine the response of growing pigs to diets supplemented with free lysine when fed either once daily or in six equal portions at intervals of 3 h. The effect of dry or wet feeding on the response to free lysine was examined in Expt nos. 4 and 5. The assumption of linear lysine response over the range of lysine supplementation was examined in Expt no. 6. 2. A significant (P less than 0.01) interaction between lysine supplementation and frequency of feeding occurred for growth rate and food conversion ratio. Growth responses to the supplements of free lysine with once daily feeding were only 67% of that achieved with frequent feeding. 3. Wet feeding had no effect on the growth responses to free lysine supplements. 4. The lysine response was linear over the range of lysine supplementation examined. 5. The implication of these results to the interpretation of experiments examining the lysine requirements of pigs are discussed.