Requirement of Digestible Sulfur Amino Acids in Laying Hens Fed Sorghum- and Soybean Meal-Based Diets

Abstract

Two experiments were done to evaluate the effect of increasing levels of dietary digestible methionine (Met) and Met:cysteine (Met:Cys) ratio on the productivity of Hy-Line W-36 laying hens fed sorghum-and soybean meal-based diets. In Exp. 1, 160 hens from 68 to 75 weeks of age were assigned to four dietary levels of digestible Met (0.20 0.24, 0.28 and 0.32%). The digestible total sulfur amino acids:Lysine (TSAA:Lys) ratios were: 62, 68, 76 and 84%. In Exp. 2, 192 hens from 76-83 weeks of age were assigned to four dietary digestible Met:Cys ratios (160, 116.7, 85.7 and 62.5%). The digestible TSAA:Lys ratio was kept constant across diets (80%). Results were subjected to ANOVA and linear regression analyses. In Exp. 1, optimal egg production, egg mass, and feed efficiency responses were observed at 0.30 and 0.50% of dietary digestible Met and TSAA, respectively (quadratic effect, p<0.05). Live performance was maximized with digestible Met and TSAA in takes of 288 and 478 mg/hen/d, respectively. In Exp. 2, optimal egg production and feed efficiency responses were observed at 151 and 150% of dietary digestible Met:Cys ratios, respectively (quadratic effect, p<0.05). The digestible Met, Cys and TSAA intake to maximize egg production and feed efficiency were 313, 207 and 510 mg/hen/d, respectively. The requirements for sulfur AA in Hy-Line W-36 hens from 68 to 83 weeks of age fed sorghum-and soybean meal-based diets fell inside the range of the requirements previously estimated in hens fed corn-soybean meal based diets.

Effect of incremental levels of dietary total sulfur amino acids on performance of white leghorn laying hens fed diets containing guar (Cyamopsis tetragonoloba) meal

“…A similar observation was also made by Gomez and Angeles. 39 Increasing the concentrations of TSAA to an optimum level was able to compensate only 50% of the decrease in EP or FCR or FE, whereas EW could not be improved with TSAA supplementation and, hence, mechanisms other than a reduced availability of these amino acids might be involved in the inhibitory effect of GM on EP, EW or FCR in laying chickens. Although concentrations of Ile and Val were lower than the recommended levels in the groups fed GM, the group with TSAA 6.84 g kg −1 within the GM cluster had concentrations of Ile and Val nearer to the recommended levels, although this group had a much lower EP than the control group (without GM) containing a similar level (6.84 g kg −1 ) of TSAA.…”

“…Although data on the effect of GM inclusion on amino acid requirement could not be traced, studies conducted by Rhone‐Poulenc showed that, if tannin from sorghum is higher than 5.0 g kg −1 in the diet, amino acid digestibility is reduced, which may alter requirements. A similar observation was also made by Gomez and Angeles …”

Standardized ileal digestible methionine and cysteine requirement for laying hens

“…In the study of Gomez and Angeles (2016) the effect of the ratio of digestible MET : digestible CYS at a constant digestible M+C concentration (0.52%) was investigated. The digestible MET and CYS levels both varied from 0.20 -0.32%.…”

“…14). and egg mass (g/d/hen) based on the data of Gomez and Angeles (2016). Using the quadratic broken-line model as described in the M&M section of this document optimal dig.…”

“…Based on the data of Gomez and Angeles (2016) it seems that that increasing the digestible CYS percentage (while keeping the total SID-M+C constant) might reduce optimal performance at a constant dietary M+C supply or might increase the total digestible M+C requirement. It therefore seems logical to also set a requirement for SID-MET next to a SID-M+C requirement.…”