Wageningen updates the nearly twenty-year-old amino acid requirements of laying hens

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Wageningen updates the nearly twenty-year-old amino acid requirements of laying hens

Gepubliceerd op
3 november 2015

Wageningen UR Livestock Research conducted a meta-analysis study to update the amino acid requirements of laying hens. The study provides amino acid requirements, both on an apparent faecal digestible and on a standardised ileal digestible basis. Apparent faecal digestible requirements of the amino acids lysine, threonine and tryptophan increased by 17%, 9%, and 22%, respectively, whereas the requirement of methionine + cysteine only slightly increased (+3%) as compared to the current CVB requirements. The current requirements are based on a study published in 1996.

NRC requirements (1994) are frequently used in literature as a public reference for limiting amino acid (AA) requirements of laying hens. These values, however, are expressed on the basis of total AA intake, whereas the feed industry prefers to work with requirements expressed on an apparent faecal (AFD) or standardised ileal (SID) digestible basis. Therefore, values for AA requirements (lysine, methionine + cysteine, threonine and tryptophan) of laying hens were updated, both on a AFD and SID basis.

A meta-analysis was performed on peer reviewed dose-response studies. Studies had to meet a set of criteria before including them into evaluation. Nutrient composition of diets were recalculated by using table values of CVB (2011). Responses were fitted by use of the Wood equation, resulting in curves that predicted rate of lay, egg weight, egg mass and FCR in dependence of AA intake. The derived AA requirements are provided for realizing 95% of the maximal response on rate of lay, egg mass and FCR.

These AA requirements, and the ratio of the limiting amino acids to Lys on AFD and SID basis are summarized in the tables below.

Apparent Faecal Digestible (AFD) amino acid intake levels (mg/d) for realizing 95% of maximal response to rate of lay, egg mass and FCR, as well as the amino acid ratios relative to lysine
Basis AFD requirement (g/d) AFD requirement (relative to Lys)
Parameter Rate of lay (%) Egg mass (g/d) FCR Rate of lay (%) Egg mass (g/d) FCR
Lysine 810 820 825 100 100 100
Met+Cys 650 670 675 80 82 82
Threonine 485 500 575 60 61 70
Tryptophan 158 158 186 20 19 23

Standardized Ileal Digestible (SID) amino acid intake levels (mg/d) for realizing 95% of maximal response to rate of lay, egg mass and FCR, as well as the amino acid ratios relative to lysine
Basis SID requirement (g/d) SID requirement (relative to Lys)
Parameter Rate of lay (%) Egg mass (g/d) FCR Rate of lay (%) Egg mass (g/d) FCR
Lysine 850 855 855 100 100 100
Met+Cys 650 670 675 76 78 79
Threonine 520 530 590 61 62 69
Tryptophan 155 156 180 18 18 21