Responses of laying hens to a low‐protein diet supplemented with essential amino acids, l‐glutamic acid and/or intact protein

1. Three sequential experiments, each lasting 8 weeks, were carried out on 576 singly‐caged light hybrids.

2. In experiment 1 egg production was 84% using a conventional control diet, 61% with a basal low‐protein diet, and 79% with the basal diet supplemented with 10 essential amino acids + L‐glutamic acid (GA).

3. In experiment 2 supplementation with lysine and methionine (L + M) alone increased egg production significantly from 54 to 72%, compared with 83% with the conventional diet.

4. In experiment 3 egg production was 55% with the basal diet, 71% with the basal diet + L + M, 75% with a diet containing 141 g protein/kg + L + M, and 73% with the conventional diet.

5. In all three experiments supplementation with GA alone either gave no significant response or a depression in production.

6. Daily intakes of 1.24 g nitrogen as non‐essential amino acids and 13 to 14 g total crude protein per bird resulted in good egg production. Supplementation of the basal diet with L + M resulted in a daily intake of 413 mg methionine/bird day which was considered adequate, and a daily intake of 710 mg lysine which was considered slightly inadequate.

Notes

Present address: Swift Canadian Co. Ltd, 2 Eva Road, PO Box 505, Etobicoke, Ontario M9C 4V5, Canada.

Present address: Unilever Research Laboratory, Colworth House, Sharnbrook, Bedford MK44 1LQ, England.