Prediction models for basal endogenous losses of crude protein and amino acids in pigs.

Objective: The objectives were to validate a previously published equation for estimating basal endogenous losses (BEL) of crude protein (CP) in pigs fed nitrogen-free diets and to develop prediction equations for BEL of CP and amino acids (AA).

Methods: A total of 139 observations from 123 experiments in 117 papers that determined the BEL of CP and AA in pigs were collected. For the validation of the previous equation for the BEL of CP, 94 observations that were not used for developing the previous equation were used. All observations were used to develop novel equations for estimating BEL of CP in pigs based on the initial body weight (IBW).

Results: The validation study indicated that the slope for BEL of CP, representing a linear bias, was less than zero (-0.56; standard error [SE] = 0.130; p<0.001). The intercept for BEL of CP, representing a mean bias, was less than zero (-3.21; SE = 0.488; p<0.001). The models for estimating BEL of CP (g/kg dry matter intake) in pigs fed a nitrogen-free diet were developed: 20.36-0.077×IBW with R2 = 0.11 and p<0.001 and 20.80×e(-0.00475×IBW) with R2 = 0.12 and p<0.001. Novel linear models for estimating BEL of AA were developed using BEL of CP as the independent variable.

Conclusion: The accuracy of the previous equation for estimating BEL of CP in pigs has been improved by reflecting additional data from recent publications. In the novel linear models for estimating BEL of AA of pigs, BEL of CP was used as an independent variable.