Can pigs detect multiple amino acid deficiencies and correct them by consuming diets with different amino acids in a multiple choice-feeding setting?

Pigs are capable to repair a single amino-acid (AA) deficiency by eating higher quantities of an AA-adequate diet in a choice-feeding setting. To investigate the ability of pigs to detect and repair multiple AA deficiencies at a time, 96 pigs (n=48 pairs) were observed for 4 weeks (from 5 weeks of age) on an experimental farm. Pigs had ad libitum access to: a low protein (LP) AA-supplemented diet (+control), a LP deficient in Thr, Trp, and Val diet (-control), the two previously mentioned diets (two-choice), and the -control and three diets with sufficient Thr, Trp, Val respectively (four-choice) for three weeks (phase 1). On week four (phase 2), the AA concentration of the choice treatment diets was increased. Average daily feed intake (ADFI) and average daily gain (ADG) were recorded twice a week. In phase 1, there was no treatment effect on ADFI and ADG. In phase 2, the +control had higher ADFI compared to the -control, with the choice treatments in between, and the +control and the two-choice had higher ADG compared to the –control, with the four-choice in between. In the 2-choice, ADFI of the -control was higher than the +control for both phases. In the 4-choice, ADFI of the -control and Trp-supplemented diet was higher compared to the Thr- and Val-supplemented in phase 1, and in phase 2 the ADFI of the Trp-supplemented diet was the highest. In conclusion, pigs can detect multiple AA deficiencies and repair them by consuming AA-supplemented diet in a multiple choice-feeding setting.