Master of Science (MS)


School of Animal Science

Document Type



Feeding laying hens or broiler breeder hens organic sources of trace minerals can improve egg quality, especially as related to shell quality. The objectives of this research were to evaluate the effect of increasing laying hen dietary zinc (Zn) levels on the content of Zn and other minerals in eggs (boron (Bo), iron (Fe), and calcium (Ca)), and to evaluate the effect of feeding increasing Zn, manganese (Mn) and copper (Cu) levels from inorganic (ITM) and organic (OTM) sources on egg quality and yolk content of Zn, Mn, and Cu. In the first experiment, a total of 64 (48 weeks of age) commercial hens (Hy-Line W-36) were allotted to one of four treatments diets on day 0. There were four replicates with four hens per replicate. The dietary treatments were: 1) corn-soybean meal (C-SBM) with no added Zn (25 mg/kg total Zn from feeding ingredients), 2) C-SBM with 50 mg/kg added Zn, 3) C-SBM with 100 mg/kg added Zn, and 4) C-SBM with 150 added mg/kg Zn. The inorganic source of Zn was ZnSO4. The trial lasted 30 days. In the second trial, 600 Hy-Line W-36 hens at 26 weeks of age were used. Hens were allotted to one of five treatment diets on day 0 of the trial. A total of 10 replicates with 12 hens per replicate were used. The dietary treatments were: 1) Control - no supplementation of Zn, Mn, or Cu, 2) Zn, Mn, and Cu supplemented at 80-90-8 mg/kg from ITM, 3) Zn, Mn, and Cu supplemented at 80-90-8 mg/kg from ITM+OTM, 4) Zn, Mn, and Cu supplemented at 160-175-16 mg/kg from ITM, and 5) Zn, Mn, and Cu supplemented at 160-175-16 mg/kg from ITM+OTM. The trial lasted 84 days. The response criteria were egg weight, specific gravity, egg shell thickness, egg shell weight, albumen height, yolk height and width, Haugh units, yolk index, feed intake and feed conversion. Data were collected on three consecutive days at the end of each 28 day period. On the second day of each three day collection period, three yolks per replicate were collected and stored for analysis of Zn, Mn, and Cu content. In the first experiment, hens fed more than 100 mg/kg added Zn had reduced egg production and egg mass. Zinc content in the egg yolk was increased 23% with 150 mg/kg added Zn. In the second experiment there was no effect (P>0.05) of dietary treatment on egg production. During the first 28 day collection period, yolk Zn and Mn were highest (P<0.01) for hens fed the 160-175-16 mg/kg from ITM+OTM. In the third 28 day collection period, albumen height was highest (P<0.05) in eggs laid by hens fed the control diet and similar for hens fed all other treatment diets. Egg weight and egg mass were not affected by increasing dietary inclusion of Zn, Mn, and Cu. Feed intake was improved for the first 28 day collection period. Egg/kg of feed was increased when hens were fed the 80-90-8 mg/kg from ITM+OTM. Thus, Zn content of the egg yolk may be increased by the inclusion of ITM+OTM at rates above their requirement in layer diets.



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Release the entire work immediately for access worldwide.

Committee Chair

Lavergne, Theresia