Protein-restricted diet balanced for lysine, methionine, threonine, and tryptophan for nursery pigs elicits subsequent compensatory growth and has long term effects on protein metabolism and organ development

Compensatory growth that can enhance the growth rate of animals and has been used commonly in production. However, the underlying mechanism is largely unknown, and the long-term effects of early protein restriction (PR) on pigs mostly remain unclear. This study aimed to investigate the long-term effects of early dietary protein restriction maintaining levels of lysine, methionine, threonine, and tryptophan on protein absorption and metabolism in pigs during the grower phase. Sixty-four weaning piglets (10.0 ± 0.73 kg) were divided into two groups: a control (NP, 200 g/kg crude protein, CP) and a protein-restricted group (RP, 140 g/kg CP). After a 30-day PR, both groups were offered the same diets ad libitum for another 74 days. PR to day 30 inhibited the growth of pigs but tended to enhance growth rate (P = 0.076) and significantly improved feed: gain in the period 70−104 days. PR significantly decreased (P