Metabolomics and Proteomics Characterizing Hepatic Reactions to Dietary Linseed Oil in Duck.

The imbalance in polyunsaturated fatty acid (PUFA) composition in human food is ubiquitous and closely related to obesity and cardiovascular diseases. The development of n-3 PUFA-enriched poultry products is of great significance for optimizing fatty acid composition. This study aimed to improve our understanding of the effects of dietary linseed oil on hepatic metabolism using untargeted metabolomics and 4D label-free proteome analysis. A total of 91 metabolites and 63 proteins showed differences in abundance in duck livers between the high linseed oil and control groups. Pathway analysis revealed that the biosynthesis of unsaturated fatty acids, linoleic acid, glycerophospholipid, and pyrimidine metabolisms were significantly enriched in ducks fed with linseed oil. Meanwhile, dietary linseed oil changed liver fatty acid composition, which was reflected in the increase in the abundance of downstream metabolites, such as α-linolenic acid (ALA; 18:3n-3) as a substrate, including n-3 PUFA and its related glycerophospholipids, and a decrease in downstream n-6 PUFA synthesis using linoleic acid (LA; 18:2n-6) as a substrate. Moreover, the anabolism of PUFA in duck livers showed substrate-dependent effects, and the expression of related proteins in the process of fatty acid anabolism, such as FADS2, LPIN2, and PLA2G4A, were significantly regulated by linseed oil. Collectively, our work highlights the ALA substrate dependence during n-3 PUFA synthesis in duck livers. The present study expands our knowledge of the process products of PUFA metabolism and provides some potential biomarkers for liver health.

Effects of feeding ß-carotene on levels of ß-carotene and vitamin A in blood and tissues of beef cattle and the effects on beef quality.

The effects of feeding ß-carotene (ßC) on levels of ßC and vitamin A (retinol) in blood and tissues, and on beef quality, were evaluated in 120 steers. Each steer received supplementary ßC (at concentrations of 0, 600, 1200, or 1800 mg/day) for 90 days and then received no supplementary ßC for 60 days. ßC significantly increased in blood serum, liver, and subcutaneous and omental fat; linearly increased in the intestine and muscle; and remained unchanged in perirenal fat during supplementation. Differences between treatment groups were eliminated in subcutaneous and omental fat and in the liver by days 120 and 150, respectively, but remained significant at day 150 in blood. Retinol increased significantly in the liver and intestine during supplementation. Intramuscular fat content, meat color, and retinol in blood, muscle, or adipose tissues were not affected. Backfat thickness decreased slightly with increasing ßC supplementation and significantly differed between groups during depletion.