Substitution of crystalline L-lysine with L-lysine enriched fermentation broth in feed and effect on the performance of broiler chicks

L-lysine is a limiting amino acid in cereal grains and a certain amount is essentially required to supplement the feed for optimum growth of poultry and pigs. The study was conducted to test performance of commercial broiler chicks fed on a feed supplemented with indigenously produced crude form of L-lysine (fermentation broth). A mutant of local strain of Corynebacterium glutamicum was used as source bacterium for lysine production on cane molasses based production medium. A total of 2500 one-day-old broiler chicks (mixed sex) were allocated at random to five dietary treatments (500 chicks/treatment). Basal diet provided 8 g total lysine/kg feed (group A). Groups B and C (positive control) were supplemented with 2 and 3 g crystalline lysine-HCl/kg feed respectively, whereas groups D and E were supplemented with lysine enriched fermentation supernatant to provide similar amount of lysine to that of groups B and C. Least significant difference test revealed highly significant (P <0.001) effect of two levels of fermentation product or crystalline lysine (HCl) on broiler performance. Significant improvement(P <0.05) in feed conversion ratio (FCR) was observed in treatment groups. Linear regression analysis (R-2 values) revealed linear response of increasing lysine levels on growth and FCR from both lysine sources. Comparative analysis of antibody titres and histology of viscera revealed no toxic effect of the treatment. The results are suggestive of equal bioavailability, safety and efficacy of the test product in comparison to purified crystalline L-lysine (HCl).