Iodine toxicity in large white turkey breeder hens

Area of Science:

• Animal Science
• Poultry Nutrition
• Reproductive Biology

Background:

• Iodine is an essential trace element vital for thyroid hormone synthesis, impacting metabolism and reproduction in poultry.
• Determining the precise dietary iodine requirements for breeder hens is critical to balance reproductive performance with potential toxicity.

Purpose of the Study:

• To ascertain the appropriate dietary iodine level for Large White turkey breeder hens during a 20-week laying cycle.
• To evaluate the reproductive effects and identify toxicity thresholds of supplemental iodine in turkey breeder diets.

Main Methods:

• Turkey breeder hens were fed a basal diet supplemented with varying levels of iodine (7, 35, or 350 ppm).
• Reproductive parameters including hatchability, egg weight, egg production, and eggshell water vapor conductance were monitored.
• Embryonic mortality patterns were analyzed across different incubation stages.

Main Results:

• A basal diet containing 7 ppm iodine supported satisfactory hatchability in Large White turkey eggs.
• Supplementation with 35 or 350 ppm iodine significantly reduced hatchability (P <= .05), indicating toxic effects.
• The 350 ppm iodine level also negatively impacted egg weight, egg production, and eggshell water vapor conductance (P <= .05).

Conclusions:

• Dietary iodine levels of 35 or 350 ppm are toxic to Large White turkey breeder hens, impairing reproductive success.
• Iodine toxicity primarily affects embryos during early incubation and the pipping stage.
• The recommended dietary iodine level for optimal reproduction in these birds should be carefully managed to avoid adverse effects.