Whole Blood Transcriptome Profiling Reveals Positive Effects of Olive Leaves-Supplemented Diet on Cholesterol in Goats

SIMPLE SUMMARY: The aim of this study was to analyze the whole blood transcriptome of lactating goats fed a dietary supplementation with 10% olive leaves, one of the main by-products deriving from the olive oil chain supply. This evaluation was effective in identifying the differential regulation of the gene coding for apolipoprotein B mRNA editing enzyme catalytic subunit 2 (APOBEC2), which showed downregulated in goats that received the dietary supplementation. Taking into account the strong association between plasma apoB and low-density lipoprotein, an evaluation was performed of both blood and milk cholesterol. The obtained data demonstrated a significant lower concentration of circulating cholesterol and cholesterol released into the milk through the mammary gland, demonstrating positive effects of olive leaves feeding on animal welfare and potential health benefits for consumers. ABSTRACT: Agro-industrial by-products represent an important source of compounds credited with high biotechnological potential. In the last decade, considerable interest has developed toward the use of these matrices as dietary supplements in the zootechnical field, paying particular attention to the qualitative aspects associated with animal products. However, less is known about the effect of these matrices on gene expression and thus on animal metabolism. Therefore, the aim of this study was to analyze the whole blood transcriptome of lactating goats fed a dietary supplementation with 10% olive leaves (OL), one of the main by-products deriving from the olive oil chain supply. By applying a false discovery rate (FDR) < 0.05 and a Log2 Fold change (Log2Fc) lower than −0.5 or higher than +0.5, it was possible to identify the differential regulation of gene coding for the apolipoprotein B (apoB) mRNA editing enzyme catalytic subunit 2 (APOBEC2), which showed downregulation in goats that received the dietary supplementation. An evaluation of both blood and milk cholesterol was performed, taking into account the strong association between plasma apoB and low-density lipoprotein (LDL). Results showed significantly lower concentrations of circulating cholesterol and cholesterol released into the milk through the mammary gland, demonstrating positive effects of OL feeding on animal welfare and potential health benefits for consumers.