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The objective of this study was to calibrate the mechanistic component of a mathematical model estimating in real-time the individual lysine requirements of growing (from 25 to 55 kg body weight, BW) and finishing (from 70 to 100 kg BW) pigs. Four experimental diets were mixed daily at different proportions to provide each pig with a diet containing 60, 70, 80, 90, 100 or 110% of the estimated lysine requirements while maintaining adequate levels of all other nutrients. Sixty pigs were assigned to treatments at 25 kg BW (group 25-55) and 60 others at 70 kg BW (group 70-100). Pigs were housed in groups of 60, but fed individually.
In the 25-55 pig group, the level of lysine did not affect feed intake, but in the 70-100 group it was 5% higher in pigs fed 10% below the requirements. Average daily gain (ADG) and protein deposition (PD) increased linearly (P < 0.001) with the level of dietary lysine. In the first group, however, maximal ADG (1.00 kg/d) and PD (174 g/d) were observed in animals fed according to their requirements (100%). For the second group, maximal ADG (1.19 kg/d) and PD (185 g/d) did not appear to have been reached with diets providing 110% of estimated lysine requirements.
The factorial method used in this study to estimate the dynamic lysine requirements of individual pigs seems appropriate for pigs fed between 25 to 55 kg BW, but it appears to underestimate the requirements of heavier pigs.
G.H.Zhang, C. Pomar, J. Pomar, J. R.E. del Castillo. L’alimentation de précision chez le porc charcutier : estimation des niveaux dynamiques de lysine digestible nécessaires à la maximisation du gain de poids. 2012. Journées Recherche Porcine, 44, 171-176.