The objective of this study was to investigate whether
valine (Val) supplementation in a reduced
protein (RP) diet regulates growth performance associated with the changes in plasma
amino acids (AAs) profile, metabolism, endocrine, and neural system in piglets. Piglets or piglets with a
catheter in the precaval vein were randomly assigned to two treatments, including two RP diets with standardized ileal digestible (
SID) Val:
Lysine (Lys) ratio of 0.45 and 0.65, respectively. The results indicated that piglets in the higher
Val:Lys ratio treatment had higher average daily feed intake (ADFI) ( P < 0.001), average daily gain (ADG) ( P = 0.001), feed conversion ratio (FCR) ( P = 0.004), lower plasma
urea nitrogen ( P = 0.032), expression of gastric
cholecystokinin (CCK), and hypothalamic
pro-opiomelanocortin (
POMC). Plasma AAs profiles including postprandial plasma essential AAs (EAAs) profile and in serum, muscle, and liver involved in metabolism of AAs and
fatty acids were significantly different between two treatments. In conclusion, Val influenced growth performance associated with metabolism of AAs and
fatty acids and both endocrine and neural system in piglets.