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Bacterial debris in the gastrointestinal tract (GIT) are continuously being produced by the microbiota present upon bacterial division and death. One of the most abundant components in bacterial debris are peptidoglycans (PGN), a structural cell wall component in gram- positive and negative bacteria. The objective of this work was to investigate if addition of a novel microbial muramidase (Muramidase 007; MUR) that hydrolyzes PGN, would reduce PGN adhesion to porcine intestinal cells in-vitro and hydrolyze PGN in the GIT of swine. Adhesion efficacy of intact and MUR hydrolyzed fluorescein-isothiocyanate (FITC)-labelled PGN were compared using fluorescence-microscopy (3 wells/condition). Catalytic performance of MUR on intact FITC-labelled PGN adhered to intestinal cells were also tested. In-vivo MUR-supplementation at 50,000 LSU/kg diet to gestating and lactating sows and/or their subsequent offspring for 42-d post-weaning was investigated. Mass-spectroscopy was used to quantify soluble and total muramic acid, which is only found in PGN, in the ileal and cecal digesta (8 piglets/treatment) to calculate percentage soluble-PGN. Cell-culture data were analyzed using GraphPad-Prism 8.0 and in-vivo data using mixed-models in JMP 14.0. MUR hydrolyzed PGN adhered 10x less to the IPEC-J2 cell line culture compared to intact-PGN (P< 0.05). In addition, data show that MUR hydrolyzed PGN attached to cell surfaces by 2x, as attached PGN were also reduced by 50% following MUR incubation (P< 0.05). Offering sows MUR-diets had no carryover effect on the percentage soluble PGN in their piglets’ digesta, and there were no interactions observed for sow x piglet x tract neither (P >0.05). Percentage soluble-PGN increased in piglets fed MUR compared to control-piglets (47.18 vs. 29.84% SEM:1.624; P< 0.001) and was higher in cecal digesta compared to ileal digesta (49.91 vs. 27.11%; SEM:1.634; P< 0.001), irrespective of MUR-supplementation. These results suggest that MUR may reduce PGN adhesion to intestinal cells and may hydrolyze PGN found in the GIT.

As previous studies have demonstrated a link between the porcine intestinal microbiome and feed efficiency (FE), microbiota manipulation may offer a means of improving FE in pigs. A fecal microbiota transplantation procedure (FMTp), using fecal extracts from highly feed-efficient pigs, was performed in pregnant sows (n = 11), with a control group (n = 11) receiving no FMTp. At weaning, offspring were allocated, within sow treatment, to (i) control (n = 67; no dietary supplement) or (ii) inulin (n = 65; 6-week dietary inulin supplementation) treatments. The sow FMTp, alone or in combination with inulin supplementation in offspring, reduced offspring body weight by 8.1 to 10.6 kg at ∼140 days of age, but there was no effect on feed intake. It resulted in better FE, greater bacterial diversity, and higher relative abundances of potentially beneficial bacterial taxa (Fibrobacter and Prevotella) in offspring. Due to the FMTp and/or inulin supplementation, relative abundances of potential pathogens (Chlamydia and Treponema) in the ileum and cecal concentrations of butyric acid were significantly lower. The maternal FMTp led to a greater number of jejunal goblet cells in offspring. Inulin supplementation alone did not affect growth or FE but upregulated duodenal genes linked to glucose and volatile fatty acid homeostasis and increased the mean platelet volume but reduced ileal propionic acid concentrations, granulocyte counts, and serum urea concentrations. Overall, the FMTp in pregnant sows, with or without dietary inulin supplementation in offspring, beneficially modulated offspring intestinal microbiota (albeit mostly low-relative-abundance taxa) and associated physiological parameters. Although FE was improved, the detrimental effect on growth limits the application of this FMTp-inulin strategy in commercial pig production. IMPORTANCE As previous research suggests a link between microbiota and FE, modulation of the intestinal microbiome may be effective in improving FE in pigs. The FMTp in gestating sows, alone or in combination with postweaning dietary inulin supplementation in offspring, achieved improvements in FE and resulted in a higher relative abundance of intestinal bacteria associated with fiber degradation and a lower relative abundance of potential pathogens. However, there was a detrimental effect on growth, although this may not be wholly attributable to microbiota transplantation, as antibiotic and other interventions were also part of the FMT regimen. Therefore, further work with additional control groups is needed to disentangle the effects of each component of the FMTp in order to develop a regimen with practical applications in pig production. Additional research based on findings from this study may also identify specific dietary supplements for the promotion/maintenance of the microbiota transferred via the maternal FMTp, thereby optimizing pig growth and FE.

Interest in the role of intestinal microbiota in determining FE in pigs has increased in recent years. However, it is not known if the same FE-associated bacteria are found across different rearing environments. In this study, geographic location and intestinal sampling site had a greater influence on the pig gut microbiome than FE. This presents challenges when aiming to identify consistent reliable microbial biomarkers for FE. Nonetheless, seven FE-associated microbial taxa were common across two geographic locations and/or two batches within one location, and these indicated a potentially “healthier” and metabolically more capable microbiota in more-feed-efficient pigs. These taxa could potentially be employed as biomarkers for FE, although bacterial consortia, rather than individual taxa, may be more likely to predict FE. They may also merit consideration for use as probiotics or could be targeted by dietary means as a strategy for improving FE in pigs in the future., Optimal feed efficiency (FE) in pigs is important for economic and environmental reasons. Previous research identified FE-associated bacterial taxa within the intestinal microbiota of growing pigs. This study investigated whether FE-associated bacteria and selected FE-associated physiological traits were consistent across geographic locations (Republic of Ireland [ROI] [two batches of pigs, ROI1 and ROI2], Northern Ireland [NI], and Austria [AT]), where differences in genetic, dietary, and management factors were minimized. Pigs (n = 369) were ranked, within litter, on divergence in residual feed intake (RFI), and 100 extremes were selected (50 with high RFI and 50 with low RFI) across geographic locations for intestinal microbiota analysis using 16S rRNA amplicon sequencing and examination of FE-associated physiological parameters. Microbial diversity varied by geographic location and intestinal sampling site but not by RFI rank, except in ROI2, where more-feed-efficient pigs had greater ileal and cecal diversity. Although none of the 188 RFI-associated taxonomic differences found were common to all locations/batches, Lentisphaerae, Ruminococcaceae, RF16, Mucispirillum, Methanobrevibacter, and two uncultured genera were more abundant within the fecal or cecal microbiota of low-RFI pigs in two geographic locations and/or in both ROI batches. These are major contributors to carbohydrate metabolism, which was reflected in functional predictions. Fecal volatile fatty acids and salivary cortisol were the only physiological parameters that differed between RFI ranks. Despite controlling genetics, diet specification, dietary phases, and management practices in each rearing environment, the rearing environment, encompassing maternal influence, herd health status, as well as other factors, appears to impact intestinal microbiota more than FE. IMPORTANCE Interest in the role of intestinal microbiota in determining FE in pigs has increased in recent years. However, it is not known if the same FE-associated bacteria are found across different rearing environments. In this study, geographic location and intestinal sampling site had a greater influence on the pig gut microbiome than FE. This presents challenges when aiming to identify consistent reliable microbial biomarkers for FE. Nonetheless, seven FE-associated microbial taxa were common across two geographic locations and/or two batches within one location, and these indicated a potentially “healthier” and metabolically more capable microbiota in more-feed-efficient pigs. These taxa could potentially be employed as biomarkers for FE, although bacterial consortia, rather than individual taxa, may be more likely to predict FE. They may also merit consideration for use as probiotics or could be targeted by dietary means as a strategy for improving FE in pigs in the future.

The use of rapeseed meal (RSM) and wheat distillers dried grains with solubles (wDDGS) in pig diets is increasingand dietary supplementation with exogenous enzymes has been suggested as means of improving feed efficiencyin pigs. The objective of this experiment was to examine the effect of phytase (Phy), a xylanase andβ-glucanasecomplex (XB), protease (Prot) and their various combinations when included in a wDDGS- and RSM-based dietfed to grower-finisher pigs. As the P- and Ca- sparing effect of Phy is well proven, the objective was to examinethe additional effects of Phy beyond its P- and Ca-sparing effects. A total of 144 pigs with an initial live weight of40.1 ± 2.0 kg were assigned to 8 treatments with 9 pens (4 female and 5 male pens) per treatment and 2females or 2 males per pen. The basal diet was formulated to contain 96 and 200 g/kg of RSM and wDDGS,respectively. The basal diet was supplemented with Phy (0 or 100 mg/kg), XB (0 or 100 mg/kg), and Prot (0 or200 mg/kg) in a 2 × 2 × 2 factorial arrangement of treatments. Experimental diets were fed for 76 d. Averagedaily gain (ADG) and average daily feed intake (ADFI) were recorded, and gain to feed (G:F) was calculated.Carcass quality variables were measured at slaughter and the left forelimb of pigs fed the unsupplemented, thePhy supplemented and the Phy + Prot supplemented diets were removed to determine bone mineral density inthe third metacarpal. The inclusion of Phy, XB and Prot in the diets increased in vitro ileal digestibility of drymatter and organic matter (P< 0.05). A tendency towards a 3-way interaction among Phy, XB and Prot wasobserved for ADG (P= 0.06) and G:F (P= 0.06). The 2-way interactions and main effects did not reveal anyimprovement for any variable measured in vivo in response to dietary enzyme supplementation. Bone mineraldensity was not different for pigs fed the unsupplemented, the Phy supplemented and the Phy + Prot supple-mented diets. In conclusion, the in vitro ileal digestibility improvements observed were not always reflected inimprovements in pig growth, feed efficiency or both. The efficacy of Phy was not reduced when supplemented incombination with Prot, as ADG, G:F, carcass quality and bone mineralization were unchanged. info:eu-repo/semantics/acceptedVersion

Feed efficiency (FE) is critical in pig production for both economic and environmental reasons. As the intestinal microbiota plays an important role in energy harvest, it is likely to influence FE. Therefore, our aim was to characterize the intestinal microbiota of pigs ranked as low, medium, and high residual feed intake ([RFI] a metric for FE), where genetic, nutritional, and management effects were minimized, to explore a possible link between the intestinal microbiota and FE. Eighty-one pigs were ranked according to RFI between weaning and day 126 postweaning, and 32 were selected as the extremes in RFI (12 low, 10 medium, and 10 high). Intestinal microbiota diversity, composition, and predicted functionality were assessed by 16S rRNA gene sequencing. Although no differences in microbial diversity were found, some RFI-associated compositional differences were revealed, principally among members of Firmicutes , predominantly in feces at slaughter (albeit mainly for low-abundance taxa). In particular, microbes associated with a leaner and healthier host (e.g., Christensenellaceae , Oscillibacter , and Cellulosilyticum ) were enriched in low RFI (more feed-efficient) pigs. Differences were also observed in the ileum of low RFI pigs; most notably, Nocardiaceae ( Rhodococcus ) were less abundant. Predictive functional analysis suggested improved metabolic capabilities in these animals, especially within the ileal microbiota. Higher ileal isobutyric acid concentrations were also found in low RFI pigs. Overall, the differences observed within the intestinal microbiota of low RFI pigs compared with that of their high RFI counterparts, albeit relatively subtle, suggest a possible link between the intestinal microbiota and FE in pigs. IMPORTANCE This study is one of the first to show that differences in intestinal microbiota composition, albeit subtle, may partly explain improved feed efficiency (FE) in low residual feed intake (RFI) pigs. One of the main findings is that, although microbial diversity did not differ among animals of varying FE, specific intestinal microbes could potentially be linked with porcine FE. However, as the factors impacting FE are still not fully understood, intestinal microbiota composition may not be a major factor determining differences in FE. Nonetheless, this work has provided a potential set of microbial biomarkers for FE in pigs. Although culturability could be a limiting factor and intervention studies are required, these taxa could potentially be targeted in the future to manipulate the intestinal microbiome so as to improve FE in pigs. If successful, this has the potential to reduce both production costs and the environmental impact of pig production.

peer-reviewed Controversial information is available regarding the feed efficiency-related variation in intestinal size, structure and functionality in pigs. The present objective was therefore to investigate the differences in visceral organ size, intestinal morphology, mucosal enzyme activity, intestinal integrity and related gene expression in low and high RFI pigs which were reared at three different geographical locations (Austria, AT; Northern Ireland, NI; Republic of Ireland, ROI) using similar protocols. Pigs (n = 369) were ranked for their RFI between days 42 and 91 postweaning and low and high RFI pigs (n = 16 from AT, n = 24 from NI, and n = 60 from ROI) were selected. Pigs were sacrificed and sampled on ~day 110 of life. In general, RFI-related variation in intestinal size, structure and function was small. Some energy saving mechanisms and enhanced digestive and absorptive capacity were indicated in low versus high RFI pigs by shorter crypts, higher duodenal lactase and maltase activity and greater mucosal permeability (P < 0.05), but differences were mainly seen in pigs from AT and to a lesser degree in pigs from ROI. Additionally, low RFI pigs from AT had more goblet cells in duodenum but fewer in jejunum compared to high RFI pigs (P < 0.05). Together with the lower expression of TLR4 and TNFA in low versus high RFI pigs from AT and ROI (P < 0.05), these results might indicate differences in the innate immune response between low and high RFI pigs. Results demonstrated that the variation in the size of visceral organs and intestinal structure and functionality was greater between geographic location (local environmental factors) than between RFI ranks of pigs. In conclusion, present results support previous findings that the intestinal size, structure and functionality do not significantly contribute to variation in RFI of pigs. This project (ECO-FCE) has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 311794.