Zinc improves meat quality by modulating lipid metabolism in necrotic enteritis challenged broilers

The objective of this study was to investigate the effect of dietary zinc from different sources on meat quality and lipid metabolism in broilers challenged with necrotic enteritis (NE). 432 one day-old commercial Arbor Acres (AA) male broilers were randomly divided into six treatments with six replicates of 12 chicks each according to a 3 × 2 design of dietary zinc (basal diet, 60 mg/kg zinc glycinate and 60 mg/kg zinc sulfate) * NE challenge (control or NE). The results showed that a negative effect of NE challenge on growth performance as reflected in higher feed conversion ratios (FCR) and lower survival rate. Zinc glycinate increased leg muscle proportion, and also improved carcass proportions under NE challenge. Both sources of zinc had an improved effect on meat quality under NE challenge, with zinc sulfate significantly reducing pectoral muscle cooking loss and zinc glycinate increasing pectoral muscle shear force. Both sources of zinc significantly down-regulated the yellowness value b* of the pectoral muscle compared to the zinc-free treatment. The NE challenge increased the pH of pectoral muscle 45 min and 24 h after slaughter. The NE challenge resulted in an upregulation of thiobarbituric acid reactive substances (TBARS) of pectoral muscle after 24 hours storage, and both sources of zinc significantly decreased TBARS after five days storage. The non-targeted metabolomic result showed that zinc glycinate affected fatty acid biosynthesis pathways, and the NE challenge also up-regulated a fatty acid synthesis pathway, down-regulated a fatty acid oxidation pathway and significantly affected unsaturated fatty acid biosynthesis pathways. These results confirm the negative effects of the NE challenge on meat quality in broilers, with NE exacerbating lipid peroxidation and affecting fatty acid composition in the pectoral muscle. Moreover, zinc glycinate raised the proportion of dihomo-α-linolenic acid in the pectoral muscle. We conclude that both the NE challenge and zinc supplementation affect meat quality by influencing lipid metabolism in broilers to modulate lipid peroxidation and fatty acid composition.