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Dynamic estimation of digestible lysine levels to maximize weight gain and protein deposition in two lines of growing-finishing pigs
The objective of this study was to validate the method of estimating real-time lysine (Lys) requirements required for precision feeding systems in which pigs are fed individually with daily tailored diets. One-hundred-forty-seven pigs of two genetic types, namely 75 of a terminal cross and 72 of a maternal cross, were used in two 28-days experimental phases, one beginning at 25.8 ± 2.5 kg live weight and the other at 73.3 ± 5.2 kg live weight. The treatments were randomly assigned to the pigs according to a 2 × 4 factorial design with two genetic lines and four Lys levels (70, 85, 100, and 115% of estimated requirements). Individual pigs’ lysine requirements were estimated daily on the basis of their intake and weight gain (Hauschild et al., 2010). The two genetic lines did not differ significantly in terms of ADG, protein deposition, protein mass, or lipid mass, and therefore, only main factors average values are presented. From 25 to 50 kg live weight, this method underestimated the pigs’ Lys requirements, given that maximum protein deposition and weight gain were achieved at 115% of Lys requirements. In terms of feed efficiency, maximum performance seemed to be achieved at a lower Lys level. From 70 to 100 kg, the method adequately estimated the pigs’ requirements, given that maximum performance was achieved at 100% of Lys requirements. The results of this study show that the method of estimating Lys requirements used for precision feeding slightly underestimates the requirements of pigs from 25 to 50 kg but adequately estimates those of pigs from 70 to 100 kg.
Keywords:
Precision feeding, real-time lysine requirements, growing pigs