(Stability of Low-Inclusion Levels of Nano and Organic Trace Minerals during Long Feed Storage Periods in Relation to Apparent Nutrient Digestibility)

This study was conducted to evaluate the effects of feed storage period on the stability of different forms of zinc (Zn) and manganese (Mn) in relation to the apparent digestibility of nutrients in laying hens. Two digestibility trials were performed. In each trial, a total of 18 Lohmann LSL Classic hens were randomly allotted to three treatments (six replicates per treatment; one bird per replicate). The first trial was conducted immediately after diet preparation, whereas the second trial was carried out after 16 weeks of feed storage. Hens in the first treatment were fed the recommended commercial levels of inorganic Zn and Mn for laying hens (60 mg/kg Zn and 100 mg/kg Mn), while hens in the second and third treatments received only 50% of these levels, supplied either in organic form or as nanoparticles. The results showed that the dietary forms or levels of Zn and Mn did not significantly affect the digestibility of dry matter, ether extract, ash, or crude protein (P > 0.05). However, the reduced inclusion levels of the organic or nanoparticle forms negatively affected Zn (P < 0.01) and Mn (P < 0.05) digestibility. Feed storage for 16 weeks negatively affected the digestibility of dry matter (P < 0.05) and ether extract (P < 0.01) but did not influence ash or crude protein digestibility (P > 0.05). In addition, no significant interaction was observed between mineral form and feed storage period for any of the nutrient digestibility parameters (P > 0.05).