In standard formulations of broiler diets, lysine is frequently a limiting amino acid and its dietary supplementation is a common practice keeping in view the negative effects of lysine deficiency on growth and feed intake [1]. The conventional form in which lysine is supplemented in broiler diet is lysine hydrochloride (L-lysine.HCl) which contains 78% available lysine. L-lysine sulfate is an alternative to L-lysine.HCl and contains 52% available lysine.
Common feed ingredients vary both in their aminoacid composition and their digestibility/bioavailability(Mosenthin and Radenmacher, 2003), which is sometimes reflected as growth response. Certain amino acids suchas lysine, threonine, methionine, cystine, and tryptophan are susceptible to damage or binding to other substancessuch as carbohydrates (Maillard or browning reaction)during processing, which can render these complexes un-available for protein metabolism. Synthetic amino acidsare expected to be 100% utilized. The dried, crystallineL-Lysine HCl has been reported to have about 78.5% freelysine (Schutte and Pack, 1994).L-Lysine sulfate is pro-duced using a similar fermentation process to the one for L-lysine HCl. However, the dried biomass is maintainedin the sulfate form (product has 15% sulfate).
In conclusion, the bioavailability of lysine in lysine sulfate in promoting growth in broilers is not different fromthe lysine supplemented asL-lysine HCl, and could there-fore be used as a source of lysine in practical poultrydiets.
Difference between L-Lysine Sulphate & L-Lysine HCL
The present investigations revealed that L-lysine sulfate may be a better option as a source of supplemental lysine for broilers. Dietary supplementation of L-lysine sulfate may result in higher intake of available phosphorus, total lysine, and other amino acids and may enhance nutrient metabolizability. Increased utilization efficiency of dietary protein and higher body protein accretion were observed when L-lysine sulfate was supplemented in diet and as a consequence live weight gain and feed conversion efficiency may also be improved with L-lysine sulfate. The study finally concluded that the retained bacterial cell mass may exert a value addition effect to L-lysine sulfate and makes it a superior source of supplemental lysine for broiler chickens.