egg-white and Weight-Gain

A trial was conducted to investigate potential interactions between phytase and xylanase enzymes in wheat-based laying diets. Hens (480 ISA-White and 480 ISA-Brown) were distributed into 160 experimental units and fed one of 10 diets containing 75 to 77% wheat from 33 to 64 wk of age with a diet change at 49 wk. Two diets were adequate in P content (0.3 and 0.25% available P in the 2 phases) with or without xylanase (0 or 2,000 U/kg; Avizyme 2300, Danisco Animal Nutrition, Marlborough, Wiltshire, United Kingdom), and 8 diets had reduced P (0.2 and 0.15% available P) with or without xylanase and phytase (0, 300, 500, and 700 ppu/kg; Phyzyme 5000G, Danisco Animal Nutrition). Egg production was higher for ISA-Brown than for ISA-White hens, and ISA-Brown hens were larger. Eggs from ISA-Brown hens had lower albumen height; higher egg, shell, and albumen weights; and lower yolk weight than those from ISA-White hens. Egg production was not affected by the diet. In P-reduced diets without xylanase, phytase significantly increased BW gain in the first period with no change in feed intake or feed efficiency. In P-adequate diets, xylanase increased egg and albumen weight and albumen height. In P-reduced diets with xylanase, increasing levels of phytase increased egg and albumen weight. This trial demonstrated no negative interactions between these enzymes for production traits and no interactions between the diet and strain of hen. These data suggest that poultry producers can use these enzymes individually or together in feed for the Brown and White egg layers used in this study without concern for the strain of hen.

Topics: 6-Phytase; Animal Nutritional Physiological Phenomena; Animals; Chickens; Diet; Egg Shell; Egg White; Egg Yolk; Eggs; Endo-1,4-beta Xylanases; Female; Ovalbumin; Phosphorus; Species Specificity; Triticum; Weight Gain

Feeding a 13% CP diet based on corn and soybean meal and supplemented with methionine to laying hens results in reduced egg weight in comparison with hens fed a corn and soybean meal methionine-supplemented diet containing 16% CP. An experiment was conducted to determine whether the egg weight reduction could be eliminated by supplementing the low-protein diet with additional lysine, methionine, and tryptophan or by adding glycine and glutamic acid to increase the amino nitrogen to a level equivalent to 16% CP. The influence of the dietary treatments on the weight of the major egg components was also determined. In a second experiment, the influence of time of day of feeding the 13 or 16% CP diets on egg weight and egg components was determined. Adding additional amino nitrogen in the form of glycine and glutamic acid or increasing the levels of lysine, methionine, or tryptophan individually or in combination failed to prevent the depression in egg weight of hens fed the lower protein diet. Measurement of egg components demonstrated that the reduction in egg weight was primarily associated with a reduction in albumen content of the egg. Feeding a high-protein diet from 1400 to 0800 h and a low-protein diet from 0800 to 1400 h resulted in egg weight equivalent to that from hens continuously fed the high-protein diet. The lower weight of the albumen in eggs from hens fed a 13% CP diet may be due to a lower availability of amino acids for protein synthesis during the 3- to 4-h period when the ovum is in the magnum.

Topics: Amino Acids; Animals; Chickens; Dietary Proteins; Eating; Egg Shell; Egg White; Egg Yolk; Eggs; Female; Glycine max; Oviposition; Weight Gain; Zea mays