Gut Microbiota-Derived Metabolite Signature in Suckling and Weaned Piglets.

The gut microbiota plays a key role in intestinal development at the suckling-to-weaning transition. The objective of this study was to analyze the production of metabolites by the gut microbiota in suckling and weaned piglets. We studied piglets raised in two separate maternity farms and weaned at postnatal day 21 in the same farm. The fecal metabolome (1H nuclear magnetic resonance) and the microbiota composition (16S rRNA gene amplicon sequencing) and its predicted functions (PICRUSt2) were analyzed in the same piglets during the suckling period (postnatal day 13) and 2 days after weaning (postnatal day 23). The relative concentrations of the bacterial metabolites methylamine, dimethylamine, cadaverine, tyramine, putrescine, 5-aminovalerate, succinate, and 3-(4-hydroxyphenylpropionate) were higher during the suckling period than after weaning. In contrast, the relative concentrations of the short-chain fatty acids acetate and propionate were higher after weaning than during the suckling period. The maternity of origin of piglets also influenced the level of some bacterial metabolites (propionate and isobutyrate). The fecal metabolome signatures observed in suckling and weaned piglets were associated with specific microbiota-predicted functionalities, structure, and diversity. Gut microbiota-derived metabolites, which are differentially abundant between suckling and weaned piglets (e.g., short-chain fatty acids and biogenic amines), are known to regulate gut health. Thus, identification of metabolome signatures in suckling and weaned piglets paves the way for the development of health-promoting nutritional strategies, targeting the production of bacterial metabolites in early life.

Genetic relationships between feed efficiency and gut microbiome in pig lines selected for residual feed intake.

This study aimed to evaluate the genetic relationship between faecal microbial composition and five feed efficiency (FE) and production traits, residual feed intake (RFI), feed conversion ratio (FCR), daily feed intake (DFI), average daily gain (ADG) and backfat thickness (BFT). A total of 588 samples from two experimental pig lines developed by divergent selection for RFI were sequenced for the 16 rRNA hypervariable V3-V4 region. The 75 genera with less than 20% zero values (97% of the counts) and two α-diversity indexes were analysed. Line comparison of the microbiota traits and estimations of heritability (h2 ) and genetic correlations (rg ) were analysed. A non-metric multidimensional scaling showed line differences between genera. The α-diversity indexes were higher in the LRFI line than in the HRFI line (p < .01), with h2 estimates of 0.19 ± 0.08 (Shannon) and 0.12 ± 0.06 (Simpson). Forty-eight genera had a significant h2 (>0.125). The rg of the α-diversities indexes with production traits were negative. Some rg of genera belonging to the Lachnospiraceae, Ruminococcaceae, Prevotellaceae, Lactobacillaceae, Streptococcaceae, Rikenellaceae and Desulfovibrionaceae families significantly differed from zero (p < .05) with FE traits, RFI (3), DFI (7) and BFT (11). These results suggest that a sizable part of the variability of the gut microbial community is under genetic control and has genetic relationships with FE, including diversity indicators. It offers promising perspectives for selection for feed efficiency using gut microbiome composition in pigs.

Calcium-rich dairy matrix protects better than mineral calcium against colonic luminal haem-induced alterations in male rats.

The haemoglobin content in meat is consistently associated with an increased risk of colorectal cancer, whereas calcium may play a role as a chemopreventive agent. Using rodent models, calcium salts have been shown to prevent the promotion of haem-induced and red meat-induced colorectal carcinogenesis by limiting the bioavailability of the gut luminal haem iron. Therefore, this study aimed to compare impacts of dietary calcium provided as calcium salts or dairy matrix on gut homoeostasis perturbations by high haeminic or non-haeminic iron intakes. A 3-week intervention study was conducted using Fischer 344 rats. Compared to the ferric citrate-enriched diet, the haemoglobin-enriched diet led to increased faecal, mucosal, and urinary lipoperoxidation-related biomarkers, resulting from higher gut luminal haem iron bioavailability. This redox imbalance was associated to a dysbiosis of faecal microbiota. The addition of calcium to haemoglobin-enriched diets limited haem iron bioavailability and counteracted redox imbalance, with improved preventive efficacy when calcium was provided in dairy matrix. Data integration revealed correlations between haem-induced lipoperoxidation products and bacterial communities belonging to Peptococcaceae, Eubacterium coprostanoligenes group, and Bifidobacteriaceae. This integrated approach provides evidence of the benefits of dairy matrix as a dietary calcium vehicle to counteract the deleterious side-effects of meat consumption.

Maternal heme-enriched diet promotes a gut pro-oxidative status associated with microbiota alteration, gut leakiness and glucose intolerance in mice offspring.

Maternal environment, including nutrition and microbiota, plays a critical role in determining offspring's risk of chronic diseases such as diabetes later in life. Heme iron requirement is amplified during pregnancy and lactation, while excessive dietary heme iron intake, compared to non-heme iron, has shown to trigger acute oxidative stress in the gut resulting from reactive aldehyde formation in conjunction with microbiota reshape. Given the immaturity of the antioxidant defense system in early life, we investigated the extent to which a maternal diet enriched with heme iron may have a lasting impact on gut homeostasis and glucose metabolism in 60-day-old C3H/HeN mice offspring. As hypothesized, the form of iron added to the maternal diet differentially governed the offspring's microbiota establishment despite identical fecal iron status in the offspring. Importantly, despite female offspring was unaffected, oxidative stress markers were however higher in the gut of male offspring from heme enriched-fed mothers, and were accompanied by increases in fecal lipocalin-2, intestinal para-cellular permeability and TNF-α expression. In addition, male mice displayed blood glucose intolerance resulting from impaired insulin secretion following oral glucose challenge. Using an integrated approach including an aldehydomic analysis, this male-specific phenotype was further characterized and revealed close covariations between unidentified putative reactive aldehydes and bacterial communities belonging to Bacteroidales and Lachnospirales orders. Our work highlights how the form of dietary iron in the maternal diet can dictate the oxidative status in gut offspring in a sex-dependent manner, and how a gut microbiota-driven oxidative challenge in early life can be associated with gut barrier defects and glucose metabolism disorders that may be predictive of diabetes development.