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Abstract
With the increasing availability and use of purified nutrients such as amino acids, vitamins and minerals in poultry diets, the overall composition of these diets is becoming more uniform and defined. While this can decrease diet cost and nutrient excesses, it can also lead to the discovery that nutrients once considered as not required actually have a requirement, and that nutrients with established requirements may have higher requirements than previously thought for optimal performance. This phenomenon is especially true with trace element requirements. In the current research the potential for the supplementation of poultry diets with rare earth elements to improve egg production in hens was investigated as was the potential that organic sources of selenium could better alleviate heat stress than an inorganic source of selenium. AZOMITE® is a hydrated sodium calcium aluminosilicate containing macro and trace minerals and rare earth elements. Laying hens were fed a control diet or this diet supplemented with 0.25% Azomite from 54 through 98 weeks of age, and broiler breeder hens were fed a control diet or this diet supplemented with 0.25% Azomite from 21 weeks of age through 65 weeks of age. Heaqt stressed laying hens were fed a layer diet supplemented with equal levels of selenium derived from either sodium selenite (inorganic source), Sel-Plex® (organic source) or Selisseo® (organic source) from 42 through 71 weeks of age. In laying hens total marketable eggs, and in broiler breeder hens total settable eggs were increased (P < 0.05) with the dietary inclusion of Azomite by 8 and 9 eggs per hen, respectively. Marketable egg production was significantly (P < 0.05) greater (5 eggs per bird) for the hens fed Selisseo® relative to those fed sodium selenite, while marketable egg production in hens fed Sel-Plex® did not differ from the other 2 treatments. The results indicate that providing rare earth elements may be beneficial to egg production in hens and that feeding Selisseo® can lessen the detrimental effects of heat stress on laying hens.