Feeding alfalfa silage inoculated with feruloyl esterase-producing Limosilactobacillus reuteri to lactating dairy goats is associated with better hepatic antioxidant capacity.

Feruloyl esterase produced by certain microorganisms can help to break down plant fiber. We investigated the effects of inoculating feruloyl esterase-producing lactic acid bacteria in alfalfa silage on production performance and blood and liver markers of inflammation and oxidative stress in lactating dairy goats. Alfalfa was ensiled for 1 mo without an additive (control; CON), with Limosilactobacillus reuteri YM13 without feruloyl esterase activity (YM13), or with a feruloyl esterase-producing L. reuteri A4-2 (A4-2). Forty-two dairy goats (53 ± 4 DIM; 37.2 ± 2.3 kg BW) were randomly assigned to 1 of the 3 dietary treatments (n = 14/treatment) and fed during 60 d. Silage and composite samples (concentrate + silage) were taken weekly. Jugular vein blood samples were taken on d 20, 40, and 60 before the morning feeding. Dairy goats were milked twice per day, and milk samples were taken on d 58 to 60. Five dairy goats from each group were slaughtered at the end of the experiment, and liver tissue samples were collected for real-time quantitative PCR (RT-qPCR) assay. Serum antioxidant activity on d 20, 40, and 60, and production data were analyzed with PROC MIXED (SPSS 21.0, SPSS Inc., Chicago, IL). Biochemical indicators in silage and composite feed; serum cytokine, immunoglobulin, and biochemical indicators; and liver RT-qPCR data in samples harvested on d 60 were analyzed using one-way ANOVA (SPSS 21.0, SPSS Inc., Chicago, IL). Compared with CON and YM13, inoculating with L. reuteri A4-2 led to lower silage pH and NDF assayed with a heat-stable amylase and expressed inclusive of residual ash but greater concentrations of lactic acid and ferulic acid, as well as activities of superoxide dismutase, catalase, glutathione peroxidase, and total antioxidant capacity. Feeding A4-2 inoculated alfalfa silage did not alter DMI, milk yield, or feed efficiency. Dairy goats fed A4-2 had greater serum total antioxidant activity and lower proinflammatory cytokine concentrations at 60 d. Furthermore, we also observed greater total protein, albumin, and IgM, and lower alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase in serum in response to feeding A4-2. Compared with CON and YM13, overall mRNA abundance of the NFE2 like bZIP transcription factor 2 (NFE2L2) target genes HMOX1, NQO1, SOD2, CAT, GPX1, GPX2, and GSR was greater in the liver of goats fed A4-2. In contrast, relative to CON and YM13 groups, feeding A4-2 resulted in an overall downregulation of KEAP1 and the NF-κB signaling pathway-related genes NFKB1, RELA, NOX4, TNF, and IFNG. Overall, feruloyl esterase-producing lactic acid bacteria used as silage inoculant can confer potential health benefits without affecting production performance. Further studies to determine the specific mechanisms controlling these responses are warranted.