title: Bioavailability of lysine in Maillard browned protein as determined by plasma lysine response in rainbow trout (Salmo gairdneri).
abstract: The bioavailability of lysine in Maillard browned protein was investigated by plasma lysine response in rainbow trout (Salmo gairdneri). The concentrations of free lysine in the plasma were measured after feeding control and browned protein diets supplemented with graded levels of lysine. Bioavailability of lysine was estimated based on the amounts of supplemental lysine in the diets that resulted in rapid increases in plasma lysine. An approximately 80% loss in bioavailable lysine content was determined by this method in a fish protein isolate subjected to the Maillard browning reaction under mild conditions (40 d incubation at 37 degrees C). The nutritional damage to lysine determined by plasma lysine response was similar to that estimated in vitro by enzymatic hydrolysis and fluorodinitrobenzene reagent, but was underestimated by acid hydrolysis and trinitrobenzene sulfonic acid reagent. Rainbow trout are similar to other animals in their inability to utilize the deoxyketosyl (Amadori) compound of lysine formed in early Maillard reaction, and in their plasma response to dietary levels of essential amino acids.
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D004044:Dietary Proteins / Q000378:metabolism*; D006358:Hot Temperature; D008239:Lysine / Q000097:blood / Q000378:metabolism*; D009753:Nutritive Value; D014337:Trout
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D008239:Lysine