Broiler chicks fed low-calcium diets. 2. Increased sensitivity to copper toxicity

Area of Science:

• Animal Nutrition
• Toxicology
• Poultry Science

Background:

• Copper is an essential trace element for poultry, but excess intake can lead to toxicity.
• Dietary factors, such as calcium and phytate, can influence nutrient bioavailability and toxicity.
• Understanding these interactions is crucial for optimizing broiler diets and preventing adverse effects.

Purpose of the Study:

• To investigate the impact of dietary calcium levels on copper toxicity in young broiler chicks.
• To compare the sensitivity to copper toxicity between different diet types (casein-gelatin vs. corn-soybean meal).
• To determine the role of phytic acid in exacerbating copper toxicity.

Main Methods:

• Broiler chicks were fed diets varying in calcium content (deficient, marginal, adequate).
• Different basal diets (casein-gelatin and corn-soybean meal) were used, with and without phytic acid.
• Growth performance and liver copper concentrations were measured.
• Intestinal and biliary copper content were analyzed to assess absorption and excretion.

Main Results:

• Chicks fed diets deficient or marginal in calcium exhibited increased sensitivity to copper toxicity.
• Reduced growth rate and elevated liver copper concentrations were observed under low calcium conditions.
• The casein-gelatin diet induced greater sensitivity to copper toxicity compared to the corn-soybean meal diet.
• Phytic acid addition to the casein-gelatin diet further enhanced copper toxicity.
• Copper absorption appeared to be the primary mechanism influenced by calcium, not excretion.

Conclusions:

• Dietary calcium significantly modulates copper toxicity in broiler chicks, with deficiency exacerbating the effects.
• Diet composition, including phytate content, influences copper toxicity.
• Calcium's effect on copper toxicity is primarily mediated through intestinal absorption, highlighting the importance of dietary mineral balance.