Nitrogen balance during compensatory growth when changing the levels of dietary lysine from deficiency to sufficiency in growing pigs

Abstract

Two experiments were conducted to elucidate the nitrogen (N) balance of pigs exhibiting compensatory growth when changing the dietary lysine levels from deficiency to sufficiency. Experiment 1 elucidated whether pigs exhibited compensatory growth with dietary lysine sufficiency. Twenty 6-week-old males were assigned to one of two treatments: control and LC (lysine and control). Control pigs were fed a control diet throughout the 24-day experimental period, whereas LC pigs were fed a low lysine diet until day 21 of the experiment, followed by the control diet until the end of experiment. The dietary lysine sufficiency treatment induced an 80% increase in the growth rate of LC pigs (P < 0.05). Experiment 2 focused on the N balance of pigs that exhibited compensatory growth with dietary lysine sufficiency. Eighteen 6-week-old males were assigned to one of three treatments: control, LC, and LL (low lysine). LL pigs were fed a low lysine diet throughout the 24-day experimental period. Pigs that exhibited compensatory growth with dietary lysine sufficiency tended to retain a higher amount of N than control pigs (P = 0.10). These finding suggest that the compensatory growth induced in pigs by dietary lysine sufficiency was partly attributable to a higher level of N retention.

Mechanism of Compensatory Growth with Changing Levels of Dietary Lysine from Deficient to Sufficient in Pigs

“…We prepared two diets: a control diet with 1.15% lysine and a low-lysine diet in with 0.73% lysine (Ishida et al 2012). The diets were iso-protein and iso-energetic, meaning both diets had the same concentrations of all essential amino acids except lysine and met the nutritional requirements (NRC, 1998).…”

“…In this paper, we describe the results of our first study on compensatory growth induced by lysine in pigs (Ishida et al 2012). We then describe our studies using a rat model (Ishida et al 2011) and an in vitro model with cultured skeletal muscle cells (Ishida et al 2013) to elucidate the mechanisms of compensatory growth after restriction-realimentation with lysine alone.…”

Compensatory Growth of C2C12 Myotubes Induced by the Combined Effect of Lysine Sufficiency and Modulation of IGF-I and Glucocorticoid Levels

“…We have reported that changing from a lysine-deficient diet to a lysine-sufficient diet induced compensatory growth in rats and pigs. 2,3) These studies demonstrated for the first time that changing dietary levels of a single essential amino acid from deficient to sufficient induced compensatory growth in growing animals.…”

“…2,3) It has been reported that ad libitum feeding after restriction feeding increased plasma IGF-I concentrations to the control levels in young bulls and pigs. 4,5) IGF-I stimulates hypertrophy in myotube and skeletal muscle, [6][7][8] but the role of IGF-I during compensatory growth remains unclear.…”

“…The concentrations of IGF-I and Dex in the negative control medium were based on the serum hormone concentrations of pigs and rats as determined by our previous in vivo studies and a previous in vitro study. 2,3,12) After 18 h of incubation, the control medium was replaced with the same fresh medium (positive control, PC). The negative control medium was replaced with each of the following media: the same fresh medium (negative control, NC), the low-lysine medium containing 100 ng/mL of IGF-I and 1.0 mM Dex (IGF-I (þ) and Dex (À)), DMEM containing 50 ng/mL of IGF-I and 1.5 mM Dex (Lys (þ)), and the control medium (Lys (þ), IGF-I (þ), and Dex (À)).…”