Postruminal supply of amino acids enhances ghrelin secretion and lipid metabolism in feed-deprived sheep.

Single amino acids (AA) feeding is gaining more attention for their functional roles beyond nutritional needs. This study aimed to describe the endocrine and metabolic responses to a single AA administration (at 10% of MP for maintenance) in 48 hr fasted sheep (n = 4) receiving, over continued 4 hr, a duodenal infusate of saline (control), glutamate (Glu), glutamine (Gln), lysine HCl (Lys), threonine (Thr), or valine (Val) in a 4 by 6 Youden square design with weekly intervals. Blood samples were collected at 0, 15, 30, 60, 120, 180, and 240 min relative to the infusion onset, and plasma AA, glucose, β-hydroxybutyric acid (BHBA), nonesterified fatty acids (NEFA), ghrelin, insulin, glucagon, and insulin-like growth factor 1 (IGF-1) concentrations were measured.

Beef extract supplementation increases leg muscle mass and modifies skeletal muscle fiber types in rats.

The objective of this research was to investigate the effects of beef extract on fat metabolism, muscle mass and muscle fiber types in rats. We also investigated the synergetic effect of endurance exercise. Twenty-four male rats weighing about 270 g were assigned to two diets containing 0 or 6% beef extract (BE).

S-myotrophin promotes the hypertrophy of skeletal muscle of mice in vivo.

S-myotrophin is a newly discovered muscle growth factor. Effects of crude S-myotrophin injection on the growth and morphology of skeletal muscle of normal, ScN and mdx mice were investigated in the present study. Total dose of crude S-myotrophin was 100 microg (100 microg protein/ml x 50 microl x 20 times).