Dietary zinc oxide nanoparticles alter tissue-specific shifts in fatty acid and amino acid profiles but do not affect meat quality or targeted rumen bacteria in Haemonchus contortus-infected lambs.

This study evaluated the effects of dietary zinc oxide nanoparticles (ZnONPs; 99 mg/kg concentrate) on tissue fatty acid and amino acid profiles, zinc concentrations in meat and liver, meat quality, and selected rumen bacterial taxa in lambs experimentally infected with Haemonchus contortus. Twenty-four lambs were assigned in a factorial design based on infection status and ZnONP supplementation and fed experimental diets for 40 days. ZnONPs induced tissue- and infection-dependent changes in selected fatty acids and amino acids, particularly in rumen fluid, serum, liver, and adipose tissue, whereas muscle composition and physicochemical meat quality remained largely unchanged. ZnONPs did not increase total zinc concentrations in meat or liver tissues. Targeted qPCR revealed only small taxon-specific differences, without broad modulation of the targeted rumen bacterial populations. Overall, ZnONPs altered selected fatty acid and amino acid profiles across tissues without substantially affecting meat quality, tissue zinc concentration, or targeted rumen bacteria.