ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2025 33 take in hens fed diets containing 0.25% digestible tryptophan compared to hens fed diets formulated with 0.10% digestible tryptophan. In addition, these authors observed the effect of tryptophan on egg quality and the regression analysis revealed that the level of digestible tryptophan of 0.22% in the diet promotes better shell quality; thickness and density, corresponding to the digestible tryptophan: digestible lysine ratio equal to 27.5%. The increase in egg production through L-tryptophan supplementation in the diet of laying hens must be related to the effect of tryptophan in improving gonadotropin release as well as improving protein availability (Dong et al., 2010). According to Russell & Harms (1999) tryptophan levels below 0.13% cause a reduction in egg production and body weight in laying hens. In addition, special attention must be given to diets formulated with ingredients that have a high concentration of long-chain neutral amino acids, such as isoleucine, valine and leucine, phenylalanine, tyrosine, since these amino acids influence the requirement of tryptophan (Peganova & Eder, 2002). According to Boa Ventura (2013), tryptophan is the second limiting amino acid, followed by threonine, in complex diets for commercial laying hens, formulated with animal products, which are rich in long-chain neutral amino acids. L-tryptophan supplementation in the diet of laying hens is positively related to behavior, reducing aggression, feather pecking and cannibalism; performance parameters, improving feed consumption, egg production and quality; the antioxidant capacity, maximizing antioxidant activity at the cellular and enzymatic level; the balance of the intestinal microbiota, reducing the presence of pathogenic microorganisms. Digestible tryptophan levels up to 0.22% and digestible Trp:Lys ratio up to 27.5% have been effective in increasing egg production and improving egg quality, based on the results obtained by Katthak & Helmbrecht (2019). References are available upon request. Best Synergy in Your Anticoccidial Program Brand Page
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