Arquivo Brasileiro de Medicina Veterinária e Zootecnia
Print version ISSN 0102-0935
GERALDO, A.; BERTECHINI, A.G.; FASSANI, E.J. and RODRIGUES, P.B.. Digestible methionine plus cystine levels in diets for laying hens at the production peak. Arq. Bras. Med. Vet. Zootec. [online]. 2010, vol.62, n.5, pp. 1216-1224. ISSN 0102-0935. http://dx.doi.org/10.1590/S0102-09352010000500026.
An experiment was conduct using 360 laying hens to evaluate the dietary levels of digestible sulfur amino acids (DSAA) on performance and egg quality of hens from 25 to 41 weeks of age. Five experimental diets were formulated containing 0.578, 0.636, 0.694, 0.752, and 0.810% of DSAA and one additional diet using the recommend level. Each treatment was replicated five times with 12 birds per replicate during four evaluation periods of 28 days each. The best results for egg production, feed conversion, egg mass yield, and viable eggs were obtained by birds that consumed 729, 751, 801, and 730 DSAA mg/day, respectively. Feed intake, weight gain, percentage of yolk, and lipid yolk linearly increased with increasing levels of DSAA. A linear increase in the percentage of yolk and a linear decrease on the percentage of shell weight, Haugh unit, and specific weight were observed with increasing levels of DSAA for eggs stored during seven days. It is concluded that for the best production and egg quality, a consumption of 752 mg of DSAA or 864 mg of total sulfur amino acid per bird per day is required.
Keywords : layer; digestible amino acids; egg quality; performance.