Calcium Carbonate

In laying hens, a mixture of fine (100 mesh) and coarse (2–4mm) calcium carbonate is often preferred. Fine particles dissolve rapidly for immediate calcium supply, while coarser particles dissolve slowly overnight when hens form eggshells, providing sustained calcium availability aligned with the eggshell formation cycle.

Layer diets require 3.5–4.5% total calcium to support daily eggshell formation (each egg requires ~2g calcium). Calcium carbonate is the primary source, typically contributing 8–12% of the diet by weight to provide the required elemental calcium.

Calcium carbonate can reduce absorption of zinc, manganese, and iron if present in excess due to competition for absorption sites. Balanced calcium supplementation within recommended ranges minimises this antagonism. Calcium-to-phosphorus ratio (typically 2:1) must also be maintained for optimal mineral utilisation.

Yes. Calcium carbonate is used in aquaculture feed as a calcium supplement. Fish absorb calcium from both feed and surrounding water, so supplementation level depends on water hardness and calcium availability in the specific aquaculture system.

Feed-grade calcium carbonate must meet purity requirements including minimum CaCO₃ content (>95%), controlled heavy metal levels (particularly lead and arsenic), consistent particle size distribution, and absence of harmful microbial contamination. Compliance with feed additive regulations is essential.