The effect of various combinations of Eggshell 49® and reduced phosphorus plus phytase on egg specific gravity and egg white in laying hens
Balander, R., Klunzinger, M.W. and Tempelman, R. (1999) The effect of various combinations of Eggshell 49® and reduced phosphorus plus phytase on egg specific gravity and egg white in laying hens. Poultry Science, 78 (Sup. 1). p. 52.
Thirteen hundred and sixty eight commercial laying hens which had just been molted after 55 weeks of production were divided into 6 groups of 228. The treatments (diets) were as follows: (1) Control feed, no additives; (2) control feed with Eggshell 49 (2 pounds/ton) added at the start of the post molt lay; (3) control feed with Eggshell 49 (2 pounds/ton) added 8 weeks after the start of the post molt lay; (4) the control diet, but with a 40% reduction in available P and 2 pounds of phytase/ton; (5) diet 4, but with Eggshell 49 (2 pounds/ton) added at the start of the post molt lay; (5) diet 4, but with Eggshell 49 (2 pounds/ton) added 8 weeks after the start of the post molt lay. Eggshell 49 (ES 49) is an ”organic” mineral feed supplement from Alltech Biotechnology. Each treatment was divided into 4 reps of 57 birds (4 tier stair step cage system). Egg production was recorded daily. One flat of 30 eggs was collected from each rep each week and tested for specific gravity (SG) (720 eggs) and each egg was individually weighed. The post molt lay period was 21 weeks. Data were analyzed by week. The only clear trend was that specific gravity significantly decreased in all treatments from week 1 to week 21. Treatments 4, 5, and 6 (low P + phytase) had numerically higher SG values for 15 of the 21 weeks, however, only occasionally would the treatment with the highest SG be significantly different. Over the course of the 21 weeks, treatment 4 had the highest overall SG followed by treatments 5, 3, 6, 1 and 2. Weeks 14 - 17, Treatment 3 had the highest overall SG values, while treatment 1 had the lowest, however it was significantly different only 3 of those weeks. For 17 of the 21 weeks, treatments 4, 5 and 6 had eggs with heavier weights and the difference was often significant between the treatment with the highest weight (varied from week to week) and the weight of the eggs from treatments 1, 2 and 3. Diets with lower P + phytase generally had heavier weights (with or without ES 49) than diets with normal P levels.
|Publisher:||Poultry Science Association|
|Copyright:||1999 Poultry Science Association|
|Notes:||Abstract Only as seen in Poultry Science v.78 Supplement 1 Pp. 52|
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