Effects of functional amino acid blend dietary supplementation with different feeding regimens on growth performance and protein utilization in weaned pigs

A study was conducted to investigate the effects of functional amino acid (AA) blend dietary supplementation with different feeding regimens on growth performance and protein utilization in weaned pigs. Pigs were fed either a standard (STD) diet or a supplemental (SUP) diet, which included an additional AA blend in the STD diet. Ninety-six piglets (6.51 +/- 0.34 kg) were randomly assigned to one of four feeding regimens: a STD diet throughout the experiment, or a SUP diet for phase I (SUP7), until phase II (SUP21), or until phase III (SUP35). During phase I, pigs fed an SUP diet exhibited a greater (P < 0.05) average daily gain and gain-to-feed ratio (G:F) than those fed the STD diet. Pigs in the SUP35 group had a higher (P < 0.05) G:F than those in the SUP7 group. Pigs in the SUP21 and SUP35 groups had greater (P < 0.05) digestibility of N than those in the SUP7 group. Pigs in the SUP35 group had upregulated (P < 0.05) mRNA encoding mammalian targets of rapamycin and cationic AA transporter1 in longissimus dorsi than those in the SUP21 group. Feeding the SUP diet throughout the 5-week nursery phase is recommended to achieve optimal growth performance and protein metabolism.