The effect of dietary protein level and total sulfur amino acid:lysine ratio on egg production parameters and egg yield in Hy-Line W-98 hens.
A 3 x 3 treatment arrangement varying in dietary protein and TSAA:Lys was used to evaluate the effect of low-protein diets fed to Hy-Line W-98 laying hens. Phase I was 20 to 43 wk of age with 18.9, 17.0, and 14.4 g of protein/hen per day and 0.97, 0.85, and 0.82 TSAA:Lys, whereas phase II was 44 to 63 wk of age with 16.3, 14.6, and 13.8 g of protein/hen per day and 0.92, 0.82, and 0.72 TSAA:Lys. Egg production and feed consumption decreased from 83.7 to 82.2% and 98.8 to 95.6 g, respectively. Feed efficiency improved from 1.680 to 1.645 g of feed/g of egg mass with decreasing dietary protein. Body weight gain was similar for hens fed high or medium protein diets. In phase II, hens consuming 13.8 g of protein/day had significantly reduced egg weight compared with hens consuming 14.6 or 16.3 g of protein/day. Wet and dry albumen percentage, albumen solids, and albumen and yolk protein percentages were significantly decreased with feeding low-protein diets. Yolk protein percentage was increased from 14.85 to 15.11% when decreasing the ratio from 0.97 to 0.82. Hens consuming a low-protein diet produced eggs with the lowest specific gravity. An interaction was observed for protein retention during phase I, feeding 14.4 g of protein/day or a ratio of 0.97 improved protein retention by 9 and 16%, respectively. Overall, hens consuming 16.3 or 14.6 g of protein/hen per day performed similar to hens consuming 18.9 and 17.0 g of protein/hen per day during P1 and P2, respectively. Also, hens consuming diets containing 0.97 and 0.92 TSAA:Lys produced eggs with improved shell quality as compared with other ratios during P1 and P2, respectively.
Novak
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Department of Animal Sciences, University of Nebraska, Lincoln 68583, USA.
Yakout
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Scheideler
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D000603:Amino Acids, Sulfur / Q000032:analysis / Q000494:pharmacology*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004032:Diet / Q000662:veterinary*; D004044:Dietary Proteins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004531:Eggs; D005247:Feeding Behavior; D005260:Female; D008239:Lysine / Q000032:analysis / Q000494:pharmacology*; D010058:Oviposition / Q000187:drug effects*
D000603:Amino Acids, Sulfur; D004044:Dietary Proteins; D008239:Lysine