Response of laying hens to methionine + cystine intake by dilution technique

Abstract

-The objective of this study was to measure the response of Dekalb White laying hens to different intakes of digestible methionine + cystine (met+cys) to optimise their performance. Two hundred eighty-eight Dekalb White laying hens, ranging in age from 33 to 48 weeks, were used in the study. The birds were randomly allocated into eight treatment (levels of met+cys and the control treatment) groups with six replicates of six hens per unit. The experimental diets consisted of seven increasing levels of met+cys (1.37, 2.75, 4.14, 5.51, 6.89, 7.92 and 8.95 g kg −1 ) and were prepared using a dilution technique. A control treatment was used to confirm that the limiting response was due to met+cys intake. Egg production, feed intake, egg weight, egg mass and feed conversion per mass were measured. The data were analysed with repeated measures and regression analyses using Broken Line and Quadratic models, as well as using the combination of both models. The different met+cys intakes influenced the studied variables; all the variables except feed conversion per mass were significantly different between the periods and levels. The digestible met+cys intakes based on the association of the Broken Line and Quadratic models to optimise the birds' response to egg mass are 671 mg/bird d for 33 to 36 weeks, 728 mg/bird d for 37 to 40 weeks, 743 mg/bird d for 41 to 44 weeks, and 770 mg/bird d for 45 to 48 weeks.

Arginine requirement for egg production in Japanese quail

“…This specificity is clear when comparing the feed conversion value of the lowest level among laying birds, which for Japanese quails was 20.02 g/g, for broiler breeder hens, it was 4.94 g/g ( Silva et al., 2015b ), and for commercial laying hens, it was 4.71 g/g ( Silva et al., 2015a ). The value of 17.4 g/g obtained by Bendezu et al. (2015) with commercial laying hens was the approximation closest to that obtained in the present study.…”

“…(2015) with commercial laying hens was the approximation closest to that obtained in the present study. However, Bendezu et al. (2015) used a dilution of 85% at the lowest experimental level, resulting in 3.24% crude protein in the diet, while the crude protein value in the present study was almost double.…”

Dietary levels of methionine plus cystine and chelated copper on the chemical composition of eggs and yolk cholesterol of 49-week-old brown laying hens

“…The response obtained for the variable 'egg weight' in the present study differs from Barbosa et al (1999), who found an increase in Met + Cys levels (0.434 to 0.734%) resulted in an increased egg weight for light laying hens and semi-heavy laying hens. In contrast, Bendezu et al (2015) observed that the increase in Met + Cys content coincided with a lower egg weight for laying hens in the first production cycle. Although different studies provide contrasting results, the level of methionine in laying diets is related to egg weight (Bunchasak & Silapasorn, 2005;Brumano, 2009;Gambaro, 2014).…”

Dietary levels of methionine plus cystine and chelated copper on the chemical composition of eggs and yolk cholesterol of 49-week-old brown laying hens

“…The response obtained for the variable 'egg weight' in the present study differs from Barbosa et al (1999), who found an increase in Met + Cys levels (0.434 to 0.734%) resulted in an increased egg weight for light laying hens and semi-heavy laying hens. In contrast, Bendezu et al (2015) observed that the increase in Met + Cys content coincided with a lower egg weight for laying hens in the first production cycle. Although different studies provide contrasting results, the level of methionine in laying diets is related to egg weight (Bunchasak & Silapasorn, 2005;Brumano, 2009;Gambaro, 2014).…”