Limestone particle size and Aspergillus niger phytase in the diet of older hens

Abstract

The aim of this experiment was to evaluate the influence of limestone particle size and phytase (F) on performance, physical egg parameters, mineral digestibility and microbial colonisation in the digestive tract in older hens aged 60–71 weeks. One hundred and sixty Lohmann Brown hens were housed in enriched cages. The 2 × 2 factorial experiment included two levels of 3-phytase NATUPHOS® (0 and 350 FTU/kg), two sizes of limestone grain (coarse limestone (CL) and a mix of CL and fine limestone (FL) (1:1)) in mixed feed. All of the diets contained 4.4 g/kg of total phosphorus and 34 g/kg of calcium. Coarse limestone with F addition significantly increased hen-day egg production (p = .018). The phytase supplement at 350 FTU/kg significantly increased shell quality characteristics. Haugh units (p = .039) and albumen index (p = .008) was higher when using the limestone mix, the same applies to yolk index (p = .013). The phytase addition to the mixed feed non-significantly increased calcium and phosphorus digestibility in the ileum by 3.1 and 3.9%, respectively. Intestinal microbiota from each sample did not cluster according to the treatment; however, bacteria belonging to the genera Turicibacter and Lactobacillus occurred with higher frequency in the ileum of hens that were fed mixed feed enriched with phytase. In conclusion, limestone particle size (1 to 2 mm) with F addition at 350 FTU/kg in a wheat-maize-soybean meal-based diet increased egg production while maintaining egg content and eggshell quality in older hens. Ileal microbiota was influenced by F supplementation in the diet.

Keywords

• coarse limestone
• 3-phytase
• egg quality
• digestibility
• microbial colonisation