Microbial production of skatole in the hind gut of pigs given different diets and its relation to skatole deposition in backfat

Supplementing infant milk formula with a multi-strain synbiotic and osteopontin enhances colonic microbial colonization and modifies jejunal gene expression in lactating piglets

A total of ninety-six weaned piglets were assigned to four dietary treatments in a 2 × 2 design. The treatments included: a standard milk formula (CTR); CTR + probiotics (6.4 × 108 cfu L-1Bifidobacterium longum subsp. infantis CECT 7210 and 1.1 × 108 cfu L-1Lactobacillus rhamnosus NH001) + prebiotics (galacto-oligosaccharides 4.36 g L-1 and human-milk-oligosaccharide 0.54 g L-1) (SYN); CTR + osteopontin (0.43 g L-1) (OPN); and CTR + SYN + OPN (CON). Daily records including feed intake, body weight, and clinical signs, were maintained throughout the 15-day trial. At the end of the study samples from blood, digestive content, and gut tissues were collected to determine serum TNF-α, intestinal fermentative activity (SCFA and ammonia), colonic microbiota (16S rRNA Illumina-MiSeq), histomorphology, and jejunal gene expression (Open-Array). No statistical differences were found in weight gain; however, the animals supplemented with osteopontin exhibited higher feed intake. In terms of clinical signs, synbiotic supplementation led to a shorter duration of diarrhoea episodes. Regarding gut health, the sequenced faecal microbiota revealed better control of potentially dysbiotic bacteria with the CON diet at day 15. In the colon compartment, a significant increase in SCFA concentration, a decrease in ammonia concentration, and a significant decrease in intraepithelial lymphocyte counts were particularly observed in CON animals. The supplemented diets were also associated with modified jejunal gene expression. The synbiotic combination was characterized by the upregulation of genes related to intestinal maturation (ALPI, SI) and nutrient transport (SLC13A1, SLC15A1, SLC5A1, SLC7A8), and the downregulation of genes related to the response to pathogens (GBP1, IDO, TLR4) or the inflammatory response (IDO, IL-1β, TGF-β1). Osteopontin promoted the upregulation of a digestive function gene (GCG). Correlational analysis between the microbiota population and various intestinal environmental factors (SCFA concentration, histology, and gene expression) proposes mechanisms of communication between the gut microbiota and the host. In summary, these results suggest an improvement in the colonic colonization process and a better modulation of the immune response when milk formula is supplemented with the tested synbiotic combined with osteopontin, benefiting from a synergistic effect.

The acute effects of rumen pulse-dosing of hydrogen acceptors during methane inhibition with nitrate or 3-nitrooxypropanol in dairy cows

Dietary methane (CH4) mitigation is in some cases associated with an increased hydrogen (H2) emission. The objective of the present study was to investigate the acute and short-term effects of acceptors for H2 (fumaric acid, acrylic acid or phloroglucinol) supplemented via pulse-dosing to dairy cows fed CH4 mitigating diets (using nitrate or 3-nitrooxypropanol), on gas exchange, rumen gas and VFA composition. For this purpose, 2 individual 4 × 4 Latin square experiments were conducted with 4 periods of 3 d (nitrate supplementation) and 7 d (3-nitrooxypropanol supplementation), respectively. In each study, 4 rumen cannulated Danish Holstein cows were used. Each additive for CH4 mitigation was included in the ad libitum fed diet within the 2 experiments, to which the cows were adapted for at least 14 d. Acceptors for H2 were administered twice daily in equal portions through the rumen fistula immediately after feeding of the individual cow. In Exp. 1 (nitrate), the treatments were CON-1 (no H2-acceptor), FUM-1 (fumaric acid), ACR-1 (acrylic acid) and FUM+ACR-1 (50% FUM-1 + 50% ACR-1). In Exp. 2 (3-nitrooxypropanol), the 3 treatments, CON-2, FUM-2, and ACR-2, were similar to CON-1, FUM-1 and ACR-1 treatments, however the fourth treatment was PHL-2 (phloroglucinol). Gas exchanges were measured in respiration chambers, while samples of rumen liquid and headspace gas were taken in time series relative to feeding and dosing on specific days. Headspace gas was analyzed for gas composition and rumen liquid was analyzed for volatile fatty acid composition and dissolved gas concentrations. Headspace gas composition and dissolved gas concentration were only measured in Exp. 2. Dry matter intake was reduced upon acrylic acid supplementation. There were no significant effects of any treatments in any experiments on H2 emission, except for a decrease in hourly H2 emission rate (g/h) at 1 h after feeding in both experiments. In Exp. 2, H2 headspace proportions increased by ACR-2 supplementation, whereas dissolved concentrations were unaffected. In Exp. 1, cows on ACR-1 increased propionate proportion at 1 h after feeding. In Exp. 2, both FUM-2 and ACR-2 increased rumen propionate proportion in the hours after feeding and dosing. There was no effect on rumen acetate for cows on PHL-2. There was a strong positive correlation between rumen dissolved CH4 and headspace CH4 (r = 0.84), whereas the equivalent correlation was weaker for H2 (r = 0.41). For the relationship between dissolved concentrations and emissions of CH4 and of H2, there was a moderate positive correlation for CH4 (r = 0.54), whereas it was weak for H2 (r = 0.28) with zero slope. In conclusion, the results suggested that fumaric acid and acrylic acid to some extent was reduced to propionate without associative effects on measures for H2 redirection. Furthermore, phloroglucinol seemed not to be metabolized in the rumen in the present study, as no effects on rumen acetate or measures of H2 were observed. Changes in H2 headspace and emission may be a poor proxy for actual changes in the rumen fluid concentration of H2.

Magnolol-driven microbiota modulation elicits changes in tryptophan metabolism resulting in reduced skatole formation in pigs

Skatole of gut origin has garnered significant attention as a malodorous pollutant due to its escalating emissions, recalcitrance to biodegradation and harm to animal and human health. Magnolol is a health-promoting polyphenol with potential to considerably mitigate the skatole production in the intestines. To investigate the impact of magnolol and its underlying mechanism on the skatole formation, in vivo and in vitro experiments were conducted in pigs. Our results revealed that skatole concentrations in the cecum, colon, and faeces decreased by 58.24% (P = 0.088), 44.98% (P < 0.05) and 43.52% (P < 0.05), respectively, following magnolol supplementation. Magnolol supplementation significantly decreased the abundance of Lachnospira, Faecalibacterium, Paramuribaculum, Faecalimonas, Desulfovibrio, Bariatricus, and Mogibacterium within the colon (P < 0.05). Moreover, a strong positive correlation (P < 0.05) between skatole concentration and Desulfovibrio abundance was observed. Subsequent in silico studies showed that magnolol could dock well with indolepyruvate decarboxylase (IPDC) within Desulfovibrio. Further in vitro investigation unveiled that magnolol addition led to less indole-3-pyruvate diverted towards the oxidative skatole pathway by the potential docking of magnolol towards IPDC, thereby diminishing the conversion of substrate into skatole. Our findings offer novel targets and strategies for mitigating skatole emission from the source.

Gas exchange, rumen hydrogen sinks, and nutrient digestibility and metabolism in lactating dairy cows fed 3-nitrooxypropanol and cracked rapeseed

Fat in the form of cracked rapeseed and 3-nitrooxypropanol (3-NOP, market as Bovaer) were fed alone or in combination to 4 Danish Holstein multicannulated dairy cows, with the objective to investigate effects on gas exchange, dry matter intake (DMI), nutrient digestion, and nutrient metabolism. The study design was a 4 × 4 Latin square with a 2 × 2 factorial treatment arrangement with 2 levels of fat supplementation; 33 g of crude fat per kg of dry matter (DM) or 64 g of crude fat per kg of DM for low and high fat diets, respectively, and 2 levels of 3-NOP; 0 mg/kg DM or 80 mg/kg DM. In total, 4 diets were formulated: low fat (LF), high fat (HF), 3-NOP and low fat (3LF), and 3-NOP and high fat (3HF). Cows were fed ad libitum and milked twice daily. The adaptation period lasted 11 d, followed by 5 d with 12 diurnal sampling times of digesta and ruminal fluid. Thereafter, gas exchange was measured for 5 d in respiration chambers. Chromic oxide and titanium dioxide were used as external flow markers to determine intestinal nutrient flow. No interactions between fat supplementation and 3-NOP were observed for methane yield (g/kg DM), total-tract digestibility of nutrients or total volatile fatty acid (VFA) concentration in the rumen. Methane yield (g/kg DMI) was decreased by 24% when cows were fed 3-NOP. In addition, 3-NOP increased carbon dioxide and hydrogen yield (g/kg DM) by 6% and 3,500%, respectively. However, carbon dioxide production was decreased when expressed on a daily basis. Fat supplementation did not affect methane yield but tended to reduce methane in percent of gross energy intake. A decrease (11%) in DMI was observed, when cows were fed 3-NOP. Likely, the lower DMI mediated a lower passage rate causing the tendency to higher rumen and total-tract neutral detergent fiber digestibility, when the cows were fed 3-NOP. Total VFA concentrations in the rumen were negatively affected both by 3-NOP and fat supplementation. Furthermore, 3-NOP caused a shift in the VFA fermentation profile, with decreased acetate proportion and increased butyrate proportion, whereas propionate proportion was unaffected. Increased concentrations of the alcohols methanol, ethanol, propanol, butanol, and 2-butanol were observed in the ruminal fluid when cows were fed 3-NOP. These changes in rumen metabolites indicate partial re-direction of hydrogen into other hydrogen sinks, when methanogenesis is inhibited by 3-NOP. In conclusion, fat supplementation did not reduce methane yield, whereas 3-NOP reduced methane yield, irrespective of fat level. However, the concentration of 3-NOP and diet composition and resulting desired mitigation effect must be considered before implementation. The observed reduction in DMI with 80 mg 3-NOP/kg DM was intriguing and may indicate that a lower dose should be applied in a Northern European context; however, the mechanism behind needs further investigation.

Mulberry leaf supplementation inhibits skatole deposition by regulating gut microbiota and upregulating liver cytochrome P450 1A1 expression in finishing pigs

Skatole, a strong fecal odor substance, is generated through microbial degradation of tryptophan in the animal hindgut. It easily accumulates in adipose tissue and affects meat quality. In this study, the effect of mulberry leaf supplementation on skatole in finishing pigs was studied. In a 35-day trial, 20 finishing pigs (barrows and gilts) were fed with a basal diet or basal diet with 6% mulberry leaves. Growth performance of the pigs (n = 10) was automatically recorded by a performance-testing feeder system and 8 pigs in each treatment were slaughtered and sampled for the remaining tests. Skatole and short-chain fatty acids were detected using HPLC and gas chromatography, respectively. Fecal microbiota were analyzed using 16S rRNA gene sequencing. The metabolomics analysis of feces and serum was performed with UHPLC-MS/MS. The major cytochrome P450 (CYP) enzymes that catalyze skatole degradation in the liver were tested by using RT-PCR and Western blot. Effects of major bioactive compounds in mulberry leaves on the CYP genes were verified in the hepatic cell line HepG2 in an in vitro test (n = 3). In finishing pigs, mulberry leaf supplementation had no significant effect on the average daily gain, average daily feed intake, and feed conversion ratio (P > 0.05), but reduced skatole levels in feces, serum, and backfat (P < 0.05), and increased acetic acid levels in feces (P = 0.027). Mulberry leaf supplementation decreased the relative abundance of the skatole-producing bacteria Megasphaera and Olsenella (P < 0.05). Indole-3-acetic acid, the intermediate that is essential for skatole production, was significantly reduced in feces by mulberry leaf supplementation (P < 0.05) and was positively correlated with skatole content in feces (P = 0.004). In pigs treated with mulberry leaves, liver CYP1A1 expression was increased (P < 0.05) and was negatively correlated with skatole content in backfat (P = 0.045). The in vitro test demonstrated that mulberry leaf polyphenols and polysaccharides could directly stimulate CYP1A1 expression in hepatic cells. These findings suggest that mulberry leaf supplementation reduces skatole production and deposition in finishing pigs by regulating the gut microbiota and promoting skatole degradation in liver.

The Impact of Fiber Source on Digestive Function, Fecal Microbiota, and Immune Response in Adult Dogs

This study evaluated the impact of different fiber sources on intestinal function, fecal microbiota, and overall health in dogs. Twelve dogs were used in a crossover design, involving three periods of 6 weeks and three diets: a low-fiber diet (CTR), a cereal-fiber and beet-pulp-supplemented diet (BRA), and a fruit-fiber-supplemented diet (FRU). Each period included a digestibility trial and fecal and blood sampling in the last week. Short-chain fatty acids (SCFAs) and microbiota taxonomy (16S rRNA Illumina-MiSeq) and functionality (Shotgun-NovaSeq 6000) were determined in the feces. General biochemistry, complete blood cells, and lymphocyte subsets were also analyzed. The fiber-supplemented diets showed lower digestibility without significant changes in the fecal consistency. The BRA diet showed higher total SCFA concentrations (p = 0.056), with increases in alpha diversity and particular beneficial genera, such as Lachnospira, Bifidobacterium, and Faecalibacterium. The BRA microbiota was also associated with an overabundance of genes related to carbohydrate and amino acid metabolism. The FRU diet had a distinct impact on the microbiota composition and functionality, leading to higher levels of CD8 lymphocytes. These findings emphasize the importance of selecting the right fiber source when formulating dog diets, as it can have a differential impact on gut microbiota and animal health.

Unravelling Effects of Rosemary (Rosmarinus officinalis L.) Extract on Hepatic Fat Accumulation and Plasma Lipid Profile in Rats Fed a High-Fat Western-Style Diet

The objective of the study was to investigate the preventive effect on obesity-related conditions of rosemary (Rosmarinus officinalis L.) extract (RE) in young, healthy rats fed a high-fat Western-style diet to complement the existing knowledge gap concerning the anti-obesity effects of RE in vivo. Sprague Dawley rats (71.3 ± 0.46 g) were fed a high-fat Western-style diet (WD) or WD containing either 1 g/kg feed or 4 g/kg feed RE for six weeks. A group fed standard chow served as a negative control. The treatments did not affect body weight; however, the liver fat percentage was reduced in rats fed RE, and NMR analyses of liver tissue indicated that total cholesterol and triglycerides in the liver were reduced. In plasma, HDL cholesterol was increased while triglycerides were decreased. Rats fed high RE had significantly increased fasting plasma concentrations of Glucagon-like peptide-1 (GLP-1). Proteomics analyses of liver tissue showed that RE increased enzymes involved in fatty acid oxidation, possibly associated with the higher fasting GLP-1 levels, which may explain the improvement of the overall lipid profile and hepatic fat accumulation. Furthermore, high levels of succinic acid in the cecal content of RE-treated animals suggested a modulation of the microbiota composition. In conclusion, our results suggest that RE may alleviate the effects of consuming a high-fat diet through increased GLP-1 secretion and changes in microbiota composition.

Gastrointestinal Microbial Ecology of Weaned Piglets Fed Diets with Different Levels of Glyphosate

Glyphosate possesses antimicrobial properties, and the present study investigated potential effects of feed glyphosate on piglet gastrointestinal microbial ecology. Weaned piglets were allocated to four diets (glyphosate contents [mg/kg feed]: 0 mg/kg control [CON; i.e., basal diet with no glyphosate added], 20 mg/kg as Glyphomax commercial herbicide [GM20], and 20 mg/kg [IPA20] and 200 mg/kg [IPA200] as glyphosate isopropylamine [IPA] salt). Piglets were sacrificed after 9 and 35 days of treatment, and stomach, small intestine, cecum, and colon digesta were analyzed for glyphosate, aminomethylphosphonic acid (AMPA), organic acids, pH, dry matter content, and microbiota composition. Digesta glyphosate contents reflected dietary levels (on day 35, 0.17, 16.2, 20.5, and 207.5 mg/kg colon digesta, respectively). Overall, we observed no significant glyphosate-associated effects on digesta pH, dry matter content, and-with few exceptions-organic acid levels. On day 9, only minor gut microbiota changes were observed. On day 35, we observed a significant glyphosate-associated decrease in species richness (CON, 462; IPA200, 417) and in the relative abundance of certain Bacteroidetes genera: CF231 (CON, 3.71%; IPA20, 2.33%; IPA200, 2.07%) and g_0.24 (CON, 3.69%; IPA20, 2.07%; IPA200, 1.75%) in cecum. No significant changes were observed at the phylum level. In the colon, we observed a significant glyphosate-associated increase in the relative abundance of Firmicutes (CON, 57.7%; IPA20, 69.4%; IPA200, 66.1%) and a decrease in Bacteroidetes (CON, 32.6%; IPA20, 23.5%). Significant changes were only observed for few genera, e.g., g_0.24 (CON, 7.12%; IPA20, 4.59%; IPA200, 4.00%). In conclusion, exposing weaned piglets to glyphosate-amended feed did not affect gastrointestinal microbial ecology to a degree that was considered actual dysbiosis, e.g., no potential pathogen bloom was observed. IMPORTANCE Glyphosate residues can be found in feed made from genetically modified glyphosate-resistant crops treated with glyphosate or from conventional crops, desiccated with glyphosate before harvest. If these residues affect the gut microbiota to an extent that is unfavorable to livestock health and productivity, the widespread use of glyphosate on feed crops may need to be reconsidered. Few in vivo studies have been conducted to investigate potential impact of glyphosate on the gut microbial ecology and derived health issues of animals, in particular livestock, when exposed to dietary glyphosate residues. The aim of the present study was therefore to investigate potential effects on the gastrointestinal microbial ecology of newly weaned piglets fed glyphosate-amended diets. Piglets did not develop actual gut dysbiosis when fed diets, containing a commercial herbicide formulation or a glyphosate salt at the maximum residue level, defined by the European Union for common feed crops, or at a 10-fold-higher level.

Effect of Particle Size of Wheat and Barley Grain on the Digestibility and Fermentation of Carbohydrates in the Small and Large Intestines of Growing Pigs

The objective of this investigation was to study the effects of different cereal types, barley and wheat, with different particle sizes (PS) on the recovery of ileal digesta and fecal excretion, digestion of nutrients and fiber components, mean transit time (MTT), and short-chain fatty acid content and composition in growing pigs studied in two experiments. Five barrows with ileal cannulas (initial BW 35.9 ± 1.5 kg) in Experiment 1 and thirty-two castrated pigs (30.8 ± 1.3 kg) in Experiment 2 were fed four different diets: barley fine, barley coarse, wheat fine and wheat coarse diets. The cereal type and PS did not influence the relative weight of the small and large intestines and pH of digesta, whereas MTT in the large intestine of pigs fed the coarse barley diet was lower compared to pigs fed other diets (p < 0.05). Pigs fed the coarse barley diet had lower apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and fiber (p < 0.05), whereas pigs fed the fine barley diet had similar AID and ATTD to pigs fed wheat fine and coarse diets (p < 0.05). In conclusion, the barley diet was more influenced by PS in comparison to wheat, thereby inducing lower AID and ATTD of nutrient.

Composition of mucus- and digesta-associated bacteria in growing pigs with and without diarrhea differed according to the presence of colonic inflammation

BACKGROUND

In the pig production, diarrhea can occur during different growth stages including the period 4-16 weeks post weaning, during which a diarrheal outbreak also termed as colitis-complex diarrhea (CCD) can occur and it is distinct from post-weaning diarrhea (1-2 weeks post weaning). We hypothesized that CCD in growing pigs is associated with changes in colonic microbiota composition and fermentation patterns, and the aim of the present observational study was to identify changes in digesta-associated bacteria (DAB) and mucus-associated bacteria (MAB) in the colon of growing pigs with and without diarrhea. A total number of 30 pigs (8, 11, and 12 weeks of age) were selected; 20 showed clinical signs of diarrhea and 10 appeared healthy. Based on histopathological examination of colonic tissues, 21 pigs were selected for further studies and classified as follows: without diarrhea, no colon inflammation (NoDiar; n = 5), with diarrhea, without colonic inflammation (DiarNoInfl; n = 4), and with diarrhea, with colonic inflammation (DiarInfl; n = 12). Composition (based on 16S rRNA gene amplicon sequencing) and fermentation pattern (short-chain fatty acids; SCFA profile) of the DAB and MAB communities were characterized.

RESULTS

The DAB showed higher alpha diversity compared to MAB in all pigs, and both DAB and MAB showed lowest alpha diversity in the DiarNoInfl group. Beta diversity was significantly different between DAB and MAB as well as between diarrheal groups in both DAB and MAB. Compared to NoDiar, DiarInfl showed increased abundance of various taxa, incl. certain pathogens, in both digesta and mucus, as well as decreased digesta butyrate concentration. However, DiarNoInfl showed reduced abundance of different genera (mainly Firmicutes) compared to NoDiar, but still lower butyrate concentration.

CONCLUSION

Diversity and composition of MAB and DAB changed in diarrheal groups depending on presence/absence of colonic inflammation. We also suggest that DiarNoInfl group was at the earlier stage of diarrhea compared with DiarInfl, with a link to dysbiosis of colonic bacterial composition as well as reduced butyrate concentration, which plays a pivotal role in gut health. This could have led to diarrhea with inflammation due to a dysbiosis, associated with an increase in e.g., Escherichia-Shigella (Proteobacteria), Helicobacter (Campylobacterota), and Bifidobacterium (Actinobacteriota), which may tolerate or utilize oxygen and cause epithelial hypoxia and inflammation. The increased consumption of oxygen in epithelial mucosal layer by infiltrated neutrophils may also have added up to this hypoxia. Overall, the results confirmed that changes in DAB and MAB were associated with CCD and reduced butyrate concentration in digesta. Moreover, DAB might suffice for future community-based studies of CCD.

Looking for Possible Benefits of Combining Short-Chain Fructo-Oligosaccharides (scFOS) with Saccharomyces cerevisiae Sc 47 on Weaned Pigs Orally Challenged with Escherichia coli F4. Animals (Basel) 2023;13:ani13030526. [PMID: 36766416 PMCID: PMC9913220 DOI: 10.3390/ani13030526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The objective of this work was to evaluate the effect of supplementing short-chain fructo-oligosaccharides (scFOS) combined or not with live yeast Saccharomyces cerevisiae Sc 47 on weanling pigs challenged with Escherichia coli F4⁺. We allocated ninety-six piglets to four experimental diets: control (CTR); supplemented with scFOS (5 g/kg Profeed^® P95) (scFOS); S. cerevisiae Sc 47 (1 g/kg Actisaf^® Sc 47 HR +) (YEA); or both (SYN). Parameters included: performance; E. coli F4⁺ detection; fermentation activity; inflammatory biomarkers; and ileal histomorphology. Our results showed that supplementing scFOS was able to reduce the incidence of diarrhea, and both supplements were able to lower counts of EHEC along the gut. Supplementing scFOS was mostly associated with changes in the gut ecosystem and increases in the lactobacilli population, while S. cerevisiae Sc 47 registered increases in the numbers of ileal intraepithelial lymphocytes. The synbiotic mixture showed the lowest diarrhea incidence and fecal scores, benefiting from complementary modes of action and possible synergistic effects due to a hypothesized yeast-LAB cross-feeding phenomenon in the foregut. In conclusion, our results evidence that supplementing scFOS or Saccharomyces cerevisiae Sc 47 is efficacious to fight post-weaning colibacillosis, and combining both could be beneficial in high-risk scenarios.

A westernized diet changed the colonic bacterial composition and metabolite concentration in a dextran sulfate sodium pig model for ulcerative colitis

Introduction

Ulcerative colitis (UC) is characterized by chronic inflammation in the colonic epithelium and has a blurred etiology. A western diet and microbial dysbiosis in the colon were reported to play a role in UC development. In this study, we investigated the effect of a westernized diet, i.e., increasing fat and protein content by including ground beef, on the colonic bacterial composition in a dextran sulfate sodium (DexSS) challenged pig study.

Methods

The experiment was carried out in three complete blocks following a 2×2 factorial design including 24 six-week old pigs, fed either a standard diet (CT) or the standard diet substituted with 15% ground beef to simulate a typical westernized diet (WD). Colitis was induced in half of the pigs on each dietary treatment by oral administration of DexSS (DSS and WD+DSS, respectively). Samples from proximal and distal colon and feces were collected.

Results and discussion

Bacterial alpha diversity was unaffected by experimental block, and sample type. In proximal colon, WD group had similar alpha diversity to CT group and the WD+DSS group showed the lowest alpha diversity compared to the other treatment groups. There was a significant interaction between western diet and DexSS for beta diversity, based on Bray-Curtis dissimilarly. The westernized diet and DexSS resulted in three and seven differentially abundant phyla, 21 and 65 species, respectively, mainly associated with the Firmicutes and Bacteroidota phyla followed by Spirochaetota, Desulfobacterota, and Proteobacteria. The concentration of short-chain fatty acids (SCFA) was lowest in the distal colon. Treatment had a slight effect on the estimates for microbial metabolites that might have valuable biological relevance for future studies. The concentration of putrescine in the colon and feces and that of total biogenic amines was highest in the WD+DSS group. We conclude that a westernized diet could be a potential risk factor and an exacerbating agent for UC by reducing the abundance of SCFA-producing bacteria, increasing the abundance of pathogens such as Helicobacter trogontum, and by increasing the concentration of microbial proteolytic-derived metabolites in the colon.

Fecal Microbiota and Hair Glucocorticoid Concentration Show Associations with Growth during Early Life in a Pig Model

Identifying characteristics associated with fast or slow growth during early life in a pig model will help in the design of nutritional strategies or recommendations during infancy. The aim of this study was to identify if a differential growth during lactation and/or the nursery period may be associated with fecal microbiota composition and fermentation capacity, as well as to leave a print of glucocorticoid biomarkers in the hair. Seventy-five commercial male and female pigs showing extreme growth in the lactation and nursery periods were selected, creating four groups (First, lactation growth, d0−d21; second, nursery growth, d21−d62): Slow_Slow, Slow_Fast, Fast_Slow, and Fast_Fast. At d63 of life, hair and fecal samples were collected. Fast-growing pigs during nursery had higher cortisone concentrations in the hair (p < 0.05) and a tendency to have a lower cortisol-to-cortisone ratio (p = 0.061). Both lactation and nursery growth conditioned the fecal microbiota structure (p < 0.05). Additionally, fast-growing pigs during nursery had higher evenness (p < 0.05). Lactation growth influenced the relative abundance of eight bacterial genera, while nursery growth affected only two bacterial genera (p < 0.05). The fecal butyrate concentration was higher with fast growth in lactation and/or nursery (p < 0.05), suggesting it has an important role in growth, while total SCFA and acetate were related to lactation growth (p < 0.05). In conclusion, piglets’ growth during nursery and, especially, the lactation period was associated with changes in their microbiota composition and fermentation capacity, evidencing the critical role of early colonization on the establishment of the adult microbiota. Additionally, cortisol conversion to cortisone was increased in animals with fast growth, but further research is necessary to determine its implications.

Comparing a single dose of xylanase to a double dose or cocktail of non-starch polysaccharide-degrading enzymes in broiler chicken diets

This study compared supplementation with a single dose of xylanase to a double dose of xylanase or a non-starch polysaccharide (NSP) degrading enzyme cocktail (NSP-ase cocktail) on productive performance, nutrient utilisation and the gastrointestinal environment in broilers fed commercial diets. Cobb 500 broilers (n=1,080) were fed 12 dietary treatments; four Australian commercial diets (based on wheat-barley, wheat-maize, wheat-sorghum or wheat only) with three different enzyme treatments (single dose of xylanase (16,000 BXU/kg), double dose of xylanase (32,000 BXU/kg) or NSP-ase cocktail (xylanase, β-glucanase, cellulase, pectinase, mannanase, galactanase, arabinofuranosidase). There were 108 pens, nine replicates per dietary treatment, with 10 birds per pen. Performance (total pen body weight, feed intake and feed conversion ratio corrected for mortality) was determined at d 0-35. On d 35, one male and one female were weighed individually and used to determine breast meat, thigh and drumstick weight, dry matter (DM) contents from the gizzard, jejunum and ileum, ileal protein, energy, starch and dry matter digestibility, ileal viscosity and xylo-oligosaccharide (XOS) concentration, caecal microbiota and short chain fatty acid (SCFA) composition. The double dose of xylanase and NSP-ase cocktail had no effect on bird performance, meat yield, ileal viscosity, ileal starch, energy or DM digestibility or digesta DM content. The double xylanase dose and NSP-ase cocktail increased protein digestibility in birds fed the wheat-sorghum based diet (P=0.041) and increased caecal concentration of butyric acid in birds fed the wheat-maize based diet (P=0.040), and propionic, valeric and lactic acid and Bifidobacteria and Enterobacteria spp. in birds fed the wheat-based diet (P<0.05). The double xylanase dose increased XOS production, particularly in birds fed the wheat-barley based diets (P<0.05). The lack of performance effects observed when feeding the double xylanase dose or NSP-ase cocktail suggested that the current recommended xylanase dose (16,000 BXU/kg) is sufficient.

Influence of dietary fibre on nutrient digestibility and energy utilisation in growing pigs fed diets varying in soluble and insoluble fibres from co-products

The co-products from the industry are used to reduce costs in pig diets. However, the co-products used in pig diets are limited because of a high fibre content which is not digested by endogenous enzymes and is resistant to degradation in the small and large intestines. The aim of this study was to investigate digestibility of nutrients and energy, and energy utilisation in pigs fed diets with various soluble and insoluble dietary fibre (DF) from co-products. The experiment was performed as a 4 × 4 Latin square design (four diets and four periods) using four growing pigs (66.2 ± 7.8 kg) surgically fitted with a T-cannula in the end of the small intestine. The pigs were fed four experimental diets: low-fibre control (LF), high-fibre control (HF), high-soluble fibre (HFS) and high-insoluble fibre (HFI) diets. The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of ash, organic matter, CP, fat, carbohydrates, starch and non-starch polysaccharides (NSP) divided into cellulose and soluble and insoluble non-cellulosic polysaccharide residues were measured using chromic oxide as marker. The recovery of total solid materials, organic matter and total carbohydrates in ileal digesta in pigs fed the HF and HFS diets was higher than in pigs fed LF and HFI, whereas recovery of organic matter and total carbohydrates in faecal materials in the HFS diet was lowest (P < 0.05). AID of organic matter, total carbohydrates and starch was lowest for HFS diet (P < 0.05). ATTD of organic matter and CP was higher for LF diet compared with other diets (P < 0.05), whereas total NSP, cellulose and non-cellulosic polysaccharides residues were highest for HFS diet (P < 0.05). Lactic acid in ileal digesta was influenced by dietary composition (P < 0.05) whereas neither type nor level of DF affected short chain fatty acids. The digestible energy, metabolisable energy, net energy and retained energy intake were similar among diets without influence of DF inclusion (P > 0.05). The metabolisable energy:digestible energy ratio was lower when feeding the HFS diet because of a higher fermentative methane loss. Faecal nitrogen and carbon were positively correlated with DM intake and insoluble DF in the diets (P < 0.05), but nitrogen and carbon (% of intake) were similar among diets. The present findings suggest that high-DF co-products can be used as ingredients of pig diets when features of DF are considered.

Assessment of the Effects of the Synbiotic Combination of Bifidobacterium longum subsp. infantis CECT 7210 and Oligofructose-Enriched Inulin Against Digestive Bacterial Infections in a Piglet Model

The use of bifidobacteria as probiotics has proven to be beneficial in gastroenteric infections. Furthermore, prebiotics such as inulin can enhance the survival and growth of these bacteria. Two trials were performed to evaluate the effects of the administration of Bifidobacterium longum subsp. infantis CECT 7210 and oligofructose-enriched inulin against Salmonella enterica serovar Typhimurium or enterotoxigenic Escherichia coli (ETEC) F4. A total of 72 (Salmonella trial) and 96 (ETEC F4 trial) weaned piglets were used in a 2 × 2 design (with or without synbiotic, inoculated or not with the pathogen). After adaptation, animals were orally inoculated. Performance and clinical signs were evaluated. On days 4 and 8 (Salmonella trial) and 3 and 7 (ETEC F4 trial) post-inoculation (PI), one animal per pen was euthanized. Blood, digestive content and tissue samples were collected and microbiological counts, fermentation products, serum inflammatory markers and ileum histomorphometry analysis were performed. Both challenges had an impact on faecal consistency (p < 0.001), including the faecal shedding of Salmonella and increased numbers of enterobacteria and coliforms. The synbiotic administration did not have any effect on pathogen loads but induced changes in the fermentation profile, such as increased valeric acid in both trials as well as decreased acetic acid, except for Salmonella-challenged animals. The effect on propionate varied among trials, increasing in challenged synbiotic-treated pigs and decreasing in non-challenged ones in the Salmonella trial (P interaction = 0.013), while the opposed occurred in the ETEC F4 trial (P interaction = 0.013). The administration of the synbiotic increased intraepithelial lymphocytes (IEL; p = 0.039) on day 8 PI in the Salmonella trial and a similar trend occurred in non-challenged pigs in the ETEC F4 trial (P interaction = 0.086). The results did not provide evidence of reduced pathogen load with the synbiotic, although a modulation in fermentative activity could be identified depending on the challenge. Consistent increases were found in IEL, suggesting that this synbiotic combination has some immunomodulatory properties.

Organic acid blends improve intestinal integrity, modulate short-chain fatty acids profiles and alter microbiota of broilers under necrotic enteritis challenge

Controlling enteric diseases of broilers is crucial. Among many additives, organic acids (OA) and their blends are gaining attention to combat diseases in the post-antibiotic era. The current study evaluated the potentials of short-chain fatty acids (SCFA) and medium-chain fatty acids (MCFA) blends and/or phenolic compounds on intestinal integrity, intestinal pH, caecal microbiota, and caecal SCFA profiles of broilers under necrotic enteritis (NE) challenge. The additives used were: (A) a blend of SCFA, MCFA, and a phenolic compound (SMP), (B) a blend of free and buffered SCFA with MCFA (SMF), and (C) a blend of free and buffered SCFA with a high concentration of MCFA (SHM). A total of 1,404 male parental chicks of Ross 308 broilers were randomly allocated to 78 floor pens on hatching day with 6 treatments replicated 13 times with 18 birds per pen. The treatments were: UCC, unchallenged control; CHC, challenged control; BAC, challenged group plus zinc bacitracin; SMP, challenged group plus additive SMP; SMF, challenged group plus additive SMF; SHM, challenged group plus additive SHM. Birds were challenged with field-strain Eimeria spp. on d 9 and Clostridium perfringens on d 14. Birds challenged with NE increased fluorescein isothiocyanate dextran (FITC-d) concentration in serum, reduced acetate and butyrate concentrations, and increased Bacteroides and C. perfringens load in the caeca (P < 0.05). Birds fed additives decreased FITC-d from gut to serum, reduced Bacteroides (d 16, P < 0.05) and numerically reduced C. perfringens load compared to CHC group. Birds fed additive SHM had higher concentrations of acetate and butyrate (d 21, P < 0.05) than CHC group but were not different from SMP and SMF groups. All the additives exhibited similar intestinal protection against NE compared to the BAC group indicated by FITC-d concentration in serum, acetate, propionate and butyrate concentrations in the caeca, and caecal bacterial loads except for the C. perfringens (P > 0.05). The SMP group had a higher load compared to BAC (P < 0.05). These findings suggest the promising effects of OA blends as alternatives to BAC to ameliorate the impact of NE challenge of broilers as indicated by improved intestinal health.

Sources and levels of copper affect liver copper profile, intestinal morphology and cecal microbiota population of broiler chickens fed wheat-soybean meal diets

Super dosing copper (Cu) has long been used as an alternative to antibiotic growth-promoters in broiler chickens' diet to improve gut health. This study was designed to compare nutritional and growth-promoting levels of Cu hydroxychloride (CH) with CuSO4 on gut health bio-markers and liver mineral profile of broiler chickens. Ross 308 chicks (n = 864) were randomly assigned to eight treatments, as basal diet containing no supplemental Cu; the basal diet with 15 or 200 mg/kg Cu as CuSO4; or 15, 50, 100, 150 or 200 mg/kg Cu from CH. The highest liver Cu content was observed in birds fed the diets with 200 mg/kg CuSO4 (P < 0.01). Serum FITC-d concentration as the leaky gut marker, and liver malondialdehyde concentration were not affected. Copper level or source had no effect on cecal short chain fatty acid and the mRNA expression of five jejunal genes involved in gut integrity. Negative linear responses of Cu were observed on Lactobacillus (P = 0.032), Bacteroides (P = 0.033), and Enterobacteriaceae (P = 0.028) counts. The jejunal villus height increased in birds fed CH at 200 and 100 mg/kg (P < 0.05). Increasing Cu levels, linearly and quadratically (P < 0.001), increased Cu excretion.

Dietary soluble non-starch polysaccharide level and xylanase influence the gastrointestinal environment and nutrient utilisation in laying hens

1. The objective of this study was to examine the influence of dietary soluble non-starch polysaccharide (sNSP) level and xylanase supplementation on productive performance, viscosity and pH along the gastrointestinal tract in laying hens. Excreta moisture content, ileal and caecal microbiota and short chain fatty acid (SCFA) composition and apparent total tract nutrient utilisation was measured.2. Hyline Brown laying hens (n=144) were housed individually at 25 weeks of age and allocated to one of four wheat-based dietary treatments in a 2 × 2 factorial arrangement, consisting of two levels of sNSP (High 13.40 g/kg or Low 11.22 g/kg), with or without xylanase (0 or 12,000 BXU/kg). Birds were fed the dietary treatments for 56 days.3. Increasing dietary sNSP increased jejunum viscosity, degradability of total NSP, total tract flow of insoluble arabinose, and succinic acid concentration in the caeca (P<0.05). Feeding high sNSP decreased excreta moisture content, total tract energy retention and free oligosaccharide, total tract flow of soluble and insoluble galactose and insoluble rhamnose and fucose, and ileal acetic and lactic acid concentrations (P<0.05), and tended to reduce egg production (P=0.058).4. Supplementation with xylanase resulted in reduced jejunum and ileum viscosity, caecal pH, excreta moisture, flow of soluble arabinose and glucose and insoluble arabinose and xylose, caecal concentration of Lactobacillus sp. and isobutyric and succinic acid, and ileal concentration of Bacillus sp. and total anaerobic bacteria (P<0.05). Xylanase application also increased energy retention and insoluble and total NSP degradation, and caecal abundance of Bifidobacteria sp. and valeric acid (P<0.05).6. These results reiterated the ability of xylanase to improve nutrient digestibility and reduce excreta moisture content in laying hens, and highlighted the importance of considering dietary sNSP level in laying hen diets.

Apparent digestibility and nutritional composition of Leucaena leucocephala (Lam) leaf meal incorporated in the diets of Black Australorp and Potchefstroom Koekoek chicken breeds

The objective of the study was to determine the apparent digestibility and nutrient composition of Leucaena leucocephala leaf meal (LLM) inclusion in Black Australorp and Potchefstroom Koekoek diets. Tender and mature leaves were separately harvested from 10 individual trees and stored separately for chemical analyses. The leaves were air-dried in a well-ventilated laboratory to constant weight and milled to pass through a 1-mm sieve. A mixture of tender and mature leaves was also collected to produce a bulk leaf meal. The four iso-nitrogenous dietary treatments were 0 (control), 2.5, 5.0 and 7.5% of LLM, respectively. The apparent digestibility of two chicken breeds was also evaluated. The dry matter (DM), neutral detergent fibre (NDF), ether extract (EE), cellulose and hemicellulose of the samples did not differ between tender and mature leaves. Tender leaves had higher (P < 0.05) calcium, potassium, magnesium and sodium concentration than mature leaves. Crude protein and mimosine content were significantly (P < 0.05) higher in tender than in mature leaves. The inclusion levels of L. leucocephala leaf meal affect (P < 0.05) acid detergent fibre (ADF), neutral detergent fibre (NDF) and crude protein (CP) digestibility. Crude protein digestibility decreases as the inclusion levels of L. leucocephala increase. Both tender and mature L. leucocephala leaves have a potential nutritional value that can be used in feedstuff and can be used as a protein supplement for Black Australorp and Potchefstroom Koekoek chicken breeds.

Comparing the efficacy of stimbiotic and a combination of xylanase and beta-glucanase, in broilers fed wheat-barley based diets with high or low AME

A stimbiotic is defined as a product that stimulates a fiber-degrading microbiome to increase fiber fermentability. The aim of this study was to examine if it is more advantageous to feed a stimbiotic (xylanase + xylo-oligosaccharides [STB]) or a combination of xylanase and beta-glucanase (Xyl + BG) to broilers fed wheat-barley based diets with differing AME levels. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed 6 dietary treatments in a 2 × 3 factorial arrangement; 2 AME levels, ‘High’ or ‘Low’, which differed by 100 kcal ME/kg, and 3 additive supplementations, with no supplemental additives, STB or Xyl + BG. Diets were fed as 3 phases, starter (d 0–14), grower (d 14–21) and finisher (d 21–35). On bird age d 14, 21 and 35, total pen body weight and feed intake were determined, and feed conversion ratio corrected for mortality (cFCR) was calculated. On d 21 and d 35 ileal viscosity and beta-glucan content and caecal SCFA concentration were determined. Additive suplementation had no impact on cFCR in birds fed the low AME diet, but in birds fed the high AME diet the cFCR value was reduced in the presence of the additives (P = 0.001 and P = 0.015, at d 14–21 and d 21–35, respectively). At d 21, cecal SCFA concentration was consistently higher (P = 0.015), and ileal beta-glucan level lower (P = 0.002), in birds fed the diet supplemented with STB compared to those without additives. At d 35, ileal viscosity was lower in birds fed STB compared to those fed the diet without supplementation of additives, irrespective of diet AME level (P = 0.017). These results suggest that both STB and Xyl + BG ameliorate the antinutritive effects of the non-starch polysaccharides (NSP) present in wheat-barley based diets, resulting in improved bird performance. However, supplementation with STB induces a comparatively greater positive effect on NSP hydrolysis and SCFA production.

Soluble non-starch polysaccharide modulates broiler gastrointestinal tract environment

The aim of this study was to evaluate the importance of considering dietary soluble non-starch polysaccharides (sNSP) when formulating broiler diets, due to their impact on the gastrointestinal tract environment. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed either wheat- or corn-soybean meal-based diets formulated to contain either a high, medium or low sNSP content, resulting in 6 dietary treatments in a 2 × 3 factorial arrangement of treatments. On d14 and d 35 of age, pH of the gizzard, ileum and caeca, ileum viscosity, caecal short chain fatty acid (SCFA) concentration, and ileal and caecal microbiota profile were determined. Ileal viscosity at d 35 was greater in birds fed high sNSP compared to low sNSP (P = 0.022). At both d 14 and d 35, birds fed the wheat-based diet presented higher ileal viscosity (P < 0.001) and lower ileal pH (P = 0.027 and P < 0.001, respectively) compared to those fed the corn-based diet. At d 14, birds fed low sNSP exhibited higher caecal pH (P = 0.010) and propionic, isobutyric and valeric acid concentrations (P = 0.035, P = 0.007 and P = 0.011, respectively), and lower ileal Lactobacillus content (P = 0.043), compared to birds fed high sNSP. This effect was also seen for total SCFA (P = 0.017) and acetic acid (P = 0.005) concentrations in the caeca at d 14, but only in birds fed wheat-, not corn-, based diets. At d 35, total caecal SCFA concentration was greater in birds fed the wheat-based diet with high sNSP level compared to those fed the corn-based diet with high or low sNSP level (P = 0.028). In comparison to birds fed corn, birds fed wheat presented greater caecal concentrations of acetic, butyric, lactic, and succinic acids (P = 0.001, P < 0.001, P = 0.003 and P = 0.007, respectively) and Bifidobacteria at d 35 (P = 0.003) and succinic acid at d14 (P = 0.041). However, caecal populations of Ruminococcus and concentrations of valeric acid at d14 and isobutyric acid at d 35 were greater in birds fed the corn- compared to wheat-based diets (P = 0.043, P = 0.019 and P < 0.001, respectively). These results illustrate that dietary sNSP concentration, as well as its composition, have a direct impact on gastrointestinal viscosity and pH, and fuel beneficial microbial species, resulting in production of SCFA. It appears to be particularly important to consider sNSP level when formulating wheat-based diets for broilers.

In vitro assessment of probiotic potential of selected bacteria isolated from pig faeces with potential application of odour reduction

To evaluate the odour reduction potential of four different bacterial species such as Enterococcus faecium, Enterococcus faecalis, Acetobacter tropicalis, and Bacillus subtilis subsp. subtilis that were isolated from fresh faeces of pigs and identified based on16S rDNA gene sequence analyses. Faecal slurry in anaerobic salt medium with 1% soluble starch (which was served as control group) and the addition of four different isolated bacterial cultures (1.0 × 10⁷CFU/mL), designated as M1, M2, M3, and M4, respectively, were incubated anaerobically for 12 and 24 h. Total gas production was increased with the incubation period (p < 0.05). M1 and M4 had decreased pattern (p < 0.05) of ammonia and hydrogen sulphide gas from 12 to 24 h. The lowest total volatile fatty acids (p < 0.05), highest lactate, and moderate butyrate concentration was observed in the M1 group at 24 h of incubation. Likewise, M1 group had the lowest total biogenic amine, histamine, ethylamine, putrescine, methylamine, and cadaverine compared to the other groups (p < 0.05) at 24 h of incubation. Overall results suggest that E. faecium can be used as a potent odour reducer in pigs production.

An integrated method to produce fermented liquid feed and biologically modified biochar as cadmium adsorbents using corn stalks

The recycling of agricultural waste is a global challenge to the sustainable development of agriculture. By using corn stalks, we studied the feasibility of combining anaerobic fermentation and pyrolysis processes to produce both fermentated liquid feed and biologically modified biocharas cadmium adsorbents. Anaerobic ensiling enhanced the biodegradation of corn stalks by increasing crude protein and reducing fiber contents. After 24-h anaerobic fermentation, corn stalks silage was decomposed into the liquid filtrate and non-fermented residue. Fermented liquid feed (FLF) was prepared by storing feed and liquid filtrate (1:4.0, wt/wt) in a closed tank at 20 °C for 4 days, which showed desired properties (pH < 4.5, lactic acid bacteria greater than 9.0 lg cfu g^-1, lactic acid greater than 100 mmol L^-1). The non-fermented residue was pyrolyzed at 500 °C to prepare biologically modified biochar (BCB24). In comparison with pristine biochar produced from corn stalks (CB), anaerobic ensiling and anaerobic fermentation significantly increased the surface area, oxygen-containing functional groups, as well as mineral components in BCB24. The maximum sorption capacity of Cd(II) for BCB24 was 2.1 times of CB, suggesting that BCB24 is an effective adsorbent for Cd(II) removal from water. Our results indicated that coupling anaerobic fermentation and pyrolysis technology can significantly improve the efficiency of corn stalks recycling.

Zinc hydroxychloride supplementation improves tibia bone development and intestinal health of broiler chickens

This study was conducted to investigate the effects of zinc (Zn), as a combination of oxide (ZnO) and sulfate (ZnSO₄), compared with incremental levels of zinc hydroxychloride (ZH) on tibia traits, intestinal integrity, expression of selected jejunal genes, cecal short chain fatty acids and microbial composition in broilers. Day-old male Ross 308 chicks (n = 784) were randomly allocated to seven dietary treatments, each replicated seven times with 16 chicks per replication. The dietary treatments included a negative control diet (NC) with no supplemental Zn, a positive control (PC) with 100 mg/kg supplemental Zn from an ionic bound source combination (50 mg/kg ZnO + 50 mg/kg ZnSO₄), and the NC diet supplemented with one of 20, 40, 60, 80, or 100 mg/kg Zn as ZH. The diets were fed over starter (1–14 d) and grower (14–35 d) phases, with tissue and digesta samples collected from 3 birds per replicate on days 14 and 35. The results showed that dietary Zn level had a significant effect on tibia breaking strength on d 35 (P < 0.05), and tibia Zn concentration both on d 14 and d 35 (P < 0.01). Dietary Zn levels linearly (P < 0.01) increased cecal lactic acid production, increased Lactobacillus, and decreased Bacillus and total bacteria counts (P < 0.05). Inclusion of 80 and 100 mg/kg Zn as ZH tended to upregulate the expression of claudin-1 (P = 0.088) and tight junction protein-1 (P = 0.086). The results obtained in this study suggest that a non-Zn supplemented diet can negatively influence tibia development and gut microbiota composition in broiler chickens. Higher supplemental Zn in the diet alters cecal microbiota population in favor of Lactobacillus and can decrease the total bacterial load. Supplemental Zn level in the feed have the potential to manipulate the jejunal gut integrity at a molecular level.

Buffered formic acid and a monoglyceride blend coordinately alleviate subclinical necrotic enteritis impact in broiler chickens

The objective of this study was to evaluate the effect of 2 different doses of a partially buffered formic acid product (Amasil NA; 61% formic acid, 20.5% sodium formate), and a monoglyceride blend of short- and medium-chain fatty acids (BalanGut LS P) on necrotic enteritis (NE) infected broilers in terms of performance, intestinal microbial population and short-chain fatty acids concentrations in the gastrointestinal tract. A total of 528-day-old as hatched Ross 308 broilers were allocated to 48 pens with 11 birds in each pen. Six dietary treatments applied in the study were: T1) nonsupplemented diet (Control); T2) antibiotic supplemented diets; T3) and T4) high (Starter: 0.5%; Grower and Finisher: 0.5%) and low (Starter: 0.3%; Grower and Finisher: 0.2%) dose of Amasil NA; and groups T5) and T6) high (Starter: 0.3%; Grower and Finisher: 0.2%) and low dose (Starter: 0.3%; Grower: 0.15%; Finisher: 0.075%) of (BalanGut LS P). All birds in this study were fed starter (d 0-10), grower (d 11-24) and finisher (d 25-35) diets and challenged with NE. To induce subclinical NE, oral administrations of Eimeria oocysts (d 9) followed by inoculation of Clostridium perfringens strains (d 14 and 15) were applied. Results showed that birds fed the high dose of Amasil NA, had a higher feed conversion ratio (FCR,P < 0.05) compared to the nonsupplemented group during the starter period. Antibiotic supplementation reduced FCR during the grower (P < 0.001), finisher (P < 0.05) and overall (P < 0.001) periods of the experiment. Both levels of BalanGut LS P and low levels of Amasil NA enhanced overall FCR (P < 0.05) compared to the birds in the nonsupplemented group. Compared to the nonsupplemented group, high levels of Amasil NA and low levels of BalanGut LS P improved FCR in the finisher stage (P < 0.05). On d 16, cecum digesta of birds fed with antibiotic supplemented diets showed a significantly lower number of C. perfringens (P < 0.001) compared to the nonsupplemented and high level of BalanGut LS P group. Bacillus (P < 0.01) and Ruminococcus numbers were significantly lower in the birds fed with high level of Amasil NA (P < 0.05) compared to the antibiotic supplemented diets. High doses of Amasil NA, showed the highest propionate concentration in the cecum (P < 0.001). The study suggests that supplementation of BalanGut LS P and Amasil NA at different feeding phases may achieve optimal performance improvement in broilers under NE challenge.

Effects of the Administration of Bifidobacterium longum subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001 and Their Synbiotic Combination With Galacto-Oligosaccharides Against Enterotoxigenic Escherichia coli F4 in an Early Weaned Piglet Model

We evaluated the potential of multi-strain probiotic (Bifidobacterium longum subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001) with or without galacto-oligosaccharides against enterotoxigenic Escherichia coli (ETEC) F4 infection in post-weaning pigs. Ninety-six piglets were distributed into 32 pens assigned to five treatments: one non-challenged (CTR+) and four challenged: control diet (CTR-), with probiotics (>3 × 10¹⁰ CFU/kg body weight each, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week, animals were orally inoculated with ETEC F4. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized and samples from blood, digesta, and tissues collected. Microbiological counts, ETEC F4 real-time PCR (qPCR) quantification, fermentation products, serum biomarkers, ileal histomorphometry, and genotype for mucin 4 (MUC4) polymorphism were determined. Animals in the PRO group had similar enterobacteria and coliform numbers to the CTR+ group, and the ETEC F4 prevalence, the number of mitotic cells at day 4 PI, and villus height at day 8 PI were between that observed in the CTR+ and CTR- groups. The PRO group exhibited reduced pig major acute-phase protein (Pig-MAP) levels on day 4 PI. The PRE diet group presented similar reductions in ETEC F4 and Pig-MAP, but there was no effect on microbial groups. The SYN group showed reduced fecal enterobacteria and coliform counts after the adaptation week but, after the inoculation, the SYN group showed lower performance and more animals with high ETEC F4 counts at day 8 PI. SYN treatment modified the colonic fermentation differently depending on the MUC4 polymorphism. These results confirm the potential of the probiotic strains and the prebiotic to fight ETEC F4, but do not show any synergy when administered together, at least in this animal model.

The role of rye bran and antibiotics on the digestion, fermentation process and short-chain fatty acid production and absorption in an intact pig model

The effects of arabinoxylan (AX)-rich rye bran based diet (RB) and antibiotics on digestion, fermentation and short-chain fatty acids (SCFA) absorption were studied compared with an iso-dietary fibre (DF) cellulose based diet (CEL). Thirty female pigs (body weight 72.5 ± 3.9 kg) were fed a standard swine diet in week 1, CEL as wash-out for bran-associated bioactive components in week 2 and then divided into 3 groups fed either the CEL (n = 10) or RB (n = 20) for 2 weeks, where 10 pigs from RB had daily intramuscular antibiotic injections (RB+) and the other 10 pigs were untreated (RB-) in week 4. In RB, the degradation of AX mainly occurred in caecum and proximal colon (P < 0.01) and to a higher extent than cellulose, which on the other hand, irrespective of antibiotic treatment, was less degraded in the RB groups than in the CEL (P < 0.01). The apparent digestibility of fat and protein in the distal small intestine was lower for RB than CEL (P < 0.05), the protein digestibility remained lower in most of the colon, and the digestibility was not affected by treatment with antibiotics. The colonic concentrations of SCFA, acetate and propionate as well as the butyrate concentration in the distal colon were lower with the RB treatments compared with CEL (P < 0.01). Caecal butyrate concentrations were on the other hand higher, and a significant reduction was seen with antibiotic treatment (P < 0.001). The daily net absorption of SCFA and acetate was lower with RB than with CEL (P < 0.01). In conclusion, RB resulted in different DF degradation processes and SCFA production compared with CEL, whereas antibiotic treatment had marginal effects on the intestinal DF degradation but hampered butyrate production.

Bacillus amyloliquefaciens CECT 5940 improves performance and gut function in broilers fed different levels of protein and/or under necrotic enteritis challenge

Two studies were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/-), and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/-). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/-). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels (P < 0.001). Supplementation of BA increased BWG (P < 0.001) and reduced FCR (P = 0.043) across dietary treatments, regardless of challenge. Bacillus (P = 0.030) and Ruminococcus (P = 0.029) genomic DNA copy numbers and concentration of butyrate (P = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG (P = 0.010) and uric acid levels in serum (P < 0.001). Supplementation of BA improved BWG (P = 0.001) and FCR (P = 0.005) and increased Ruminococcus numbers (P = 0.018) and butyrate concentration (P = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced Clostridium perfringens numbers only in birds fed with RCP diets (P = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine (P = 0.013), valine (P = 0.020), and lysine (P = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.

Effects of dietary stachyose levels on caecal skatole concentration, hepatic cytochrome P450 mRNA expressions and enzymatic activities in broilers

Effects of dietary supplemental stachyose on caecal skatole concentration, hepatic cytochrome P450 (CYP450, CYP) mRNA expressions and enzymatic activities in broilers were evaluated. Arbor Acre commercial mixed male and female chicks were assigned randomly into six treatments. The positive control (PC) diet was based on maize-soyabean meal, and the negative control (NC) diet was based on maize-non-soyabean meal. The NC diet was then supplemented with 4, 5, 6 and 7 g/kg stachyose to create experimental diets, named S-4, S-5, S-6 and S-7, respectively. Each diet was fed to six replicates of ten birds from days 1 to 49. On day 49, the caecal skatole concentrations in the PC, S-4, S-5, S-6 and S-7 groups were lower than those in the NC group by 42·28, 23·68, 46·09, 15·31 and 45·14 % (P < 0·01), respectively. The lowest pH value was observed in the S-5 group (P < 0·05). The stachyose-fed groups of broilers had higher caecal acetate and propionate levels compared with control groups, and propionate levels in the S-6 and S-7 groups were higher than those in the S-4 and S-5 groups (P < 0·001). The highest CYP3A4 expression was found in the S-7 group (P < 0·05), but this was not different from PC, S-4, S-5 and S-6 treatments. There was no significant difference in CYP450 (1A2, 2D6 and 3A4) enzymatic activities among the groups (P > 0·05). In conclusion, caecal skatole levels can be influenced by dietary stachyose levels, and 5 g/kg of stachyose in the diet was suggested.

Casein glycomacropeptide is well tolerated in healthy adults and changes neither high-sensitive C-reactive protein, gut microbiota nor faecal butyrate: a restricted randomised trial

Casein glycomacropeptide (CGMP) is a bioactive milk-derived peptide with potential anti-inflammatory effects. Animal studies suggest that CGMP may work by altering gut microbiota composition and enhancing butyrate production. Its effects on intestinal homoeostasis, microbiota and metabolites in humans are unknown. The aim of the present study was to assess both the intestinal and systemic immunomodulatory effects of orally ingested CGMP. We hypothesised that daily oral CGMP intake would reduce high-sensitive C-reactive protein (hsCRP) in healthy adults. In a single-centre limited but randomised, double-blinded, reference-controlled study, we compared the effects of a 4-week intervention of either 25 g of oral powder-based chocolate-flavoured CGMP or a reference drink. We included twenty-four healthy adults who all completed the study. CGMP had no systemic or intestinal immunomodulatory effects compared with a reference drink, with regard to either hsCRP or faecal calprotectin level, faecal microbiota composition or faecal SCFA content. CGMP ingestion did not affect satiety or body weight, and it caused no severe adverse events. The palatability of CGMP was acceptable, and adherence was high. CGMP did not induce or change gastrointestinal symptoms. In conclusion, we found no immunomodulatory effects of CGMP in healthy adults. In a minor group of healthy adults, oral ingestion of 25 g of CGMP during 4 weeks was safe, well tolerated, had acceptable palatability and was without any effects on body weight.

Effects of Bifidobacterium longum Subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001, Combined or Not With Oligofructose-Enriched Inulin, on Weaned Pigs Orally Challenged With Salmonella Typhimurium

Salmonella is a common causative agent of enteric disease and is developing mechanisms of resistance to antimicrobials. Probiotics, such as bifidobacteria and lactobacilli, and prebiotic fibers are a potential alternative to counteract this pathogen as they have demonstrated effectiveness in preventing its adhesion, reducing intestinal damage, and enhancing the host immune system. Furthermore, the benefits are expected to be potentiated when these compounds are administered together. A trial was performed to evaluate the efficacy of two probiotic strains (Bifidobacterium longum subsp. infantis CECT 7210 (Laboratorios Ordesa S.L.) and Lactobacillus rhamnosus HN001, combined or not with a prebiotic containing oligofructose-enriched inulin, against Salmonella Typhimurium. Ninety-six piglets (28 days old) were distributed into 32 pens assigned to 5 treatments: one non-challenged (control diet, CTR+) and four challenged: control diet (CTR−) or supplemented with probiotics (>3 × 10¹⁰ cfu/kg each strain, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week of adaptation, animals were orally challenged with Salmonella Typhimurium. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized, and samples from blood, digestive content, and ileal tissues were collected to determine Salmonella counts, fermentation products, ileal histomorphology, and serum TNF-α and Pig-MAP concentrations. The effect of the oral challenge was evidenced by animal performance, fecal consistency, and intestinal architecture. Regarding the experimental treatments, animals belonging to the PRO group experienced a faster clearance of the pathogen, with more pigs being negative to its excretion at the end of the study and recovering the impaired ileal villi/crypt ratio more rapidly. Animals receiving the PRE diet showed a lower intestinal colonization by Salmonella, with no countable levels (<3 cfu/g) in any of the analyzed samples, and an augmented immune response suggested by serum Pig-MAP concentrations. Treatments including the prebiotic (PRE and SYN) showed similar changes in the fermentation pattern, with an increase in the molar percentage of valeric acid concentration in the colon. The SYN group, however, did not show any of the outcomes registered for PRO and PRE in Salmonella colonization or in immunity markers, suggesting the lack of synbiotic action in this animal model. Further research is needed to better understand the complex mechanisms behind these effects.

Two different Clostridium perfringens strains produce different levels of necrotic enteritis in broiler chickens

Subclinical necrotic enteritis (NE) is primarily caused by the gram-positive bacterium, Clostridium perfringens (Cp). The trend towards removal of in-feed antimicrobials and subsequent increased emergence of infection in poultry has resulted in a wide interest in better understanding of the mechanism behind this disease. The virulence of NE, to a large extent, depends on the virulence of Cp strains. Thus, this study was to assess how 2 different strains of Cp affect performance and gut characteristics of broiler chickens. Ross 308 male broilers (n = 468) were assigned to a 2 × 3 factorial arrangement of treatments with antibiotics (Salinomycin at 72 ppm and zinc bacitracin at 50 ppm -, or +) and challenge (non-challenge, Cp EHE-NE18, or Cp WER-NE36). Oral administration of Eimeria oocysts (day 9) followed by inoculation with 1 mL 108 CFU Cp strains (day 14 and 15) were used to induce NE. Broiler performance was analyzed at day 10, 24, and 35. On day 16, intestinal lesion score and intestinal pH were evaluated and samples of cecal content were analyzed for bacterial counts and short-chain fatty acid concentrations (SCFA). Birds in both challenged groups showed higher feed conversion ratio (FCR), lower weight gain (P < 0.001), increased lesion scores in the jejunum (P < 0.01), and reduced pH in the ileum and cecum (P < 0.01), compared to the non-challenged birds. They also showed decreased numbers of Bacillus spp. (P < 0.001), and Ruminococcus spp. (P < 0.01) in the cecal content. On day 35, the NE36 challenged birds had a lower weight gain (P < 0.001) and higher FCR (P < 0.001) compared to the NE18 challenged birds. Interestingly, cecal Lactobacillus and lactate were increased by the NE challenge (P < 0.001), and to a greater extent in birds challenged with NE36 compared to the NE18 strain (P < 0.001). This study suggests that Cp strains varying in virulence produce different levels of disease in broiler chickens through modulating the gut environment, intestinal microbiota, and SCFA profile to different extents.

Impact of in-feed sodium butyrate or sodium heptanoate protected with medium-chain fatty acids on gut health in weaned piglets challenged with Escherichia coli F4. Arch Anim Nutr 2020;74:271-295. [PMID: 32108496 DOI: 10.1080/1745039x.2020.1726719]

Short and medium-chain fatty acids (SCFA and MCFA, respectively) are commonly used as feed additives in piglets to promote health and prevent post-weaning diarrhoea. Considering that the mechanism and site of action of these fatty acids can differ, a combined supplementation could result in a synergistic action. Considering this, it was aimed to assess the potential of two new in-feed additives based on butyrate or heptanoate, protected with sodium salts of MCFA from coconut distillates, against enterotoxigenic Escherichia coli (ETEC) F4⁺ using an experimental disease model. Two independent trials were performed in 48 early-weaned piglets fed a control diet (CTR) or a diet supplemented with MCFA-protected sodium butyrate (BUT+; Trial 1) or sodium heptanoate (HPT+; Trial 2). After 1 week of adaptation, piglets were challenged with a single oral inoculum of ETEC F4⁺ (minimum 1.4 · 10⁹ cfu). One animal per pen was euthanised on days 4 and 8 post-inoculation (PI) and the following variables assessed: growth performance, clinical signs, gut fermentation, intestinal morphology, inflammatory mediators, pathogen excretion and colon microbiota. None of the additives recovered growth performance or reduced diarrhoea when compared to the respective negative controls. However, both elicited different responses against ETEC F4⁺. The BUT+ additive did not lead to reduce E. coli F4 colonisation but enterobacterial counts and goblet cell numbers in the ileum were increased on day 8 PI and this followed higher serum TNF-α concentrations on day 4 PI. The Firmicutes:Bacteroidetes ratio was nevertheless increased. Findings in the HPT+ treatment trial included fewer animals featuring E. coli F4 in the colon and reduced Enterobacteriaceae (determined by 16S RNA sequencing) on day 4 PI. In addition, while goblet cell numbers were lower on day 8 PI, total SCFA levels were reduced in the colon. Results indicate the efficacy of MCFA-protected heptanoate against ETEC F4⁺ and emphasise the potential trophic effect of MCFA-protected butyrate on the intestinal epithelium likely reinforcing the gut barrier.

Nørskov N, Knudsen KEB, Hedemann MS, Lærke HN. Effects of dietary fibre and protein content on intestinal fibre degradation, short-chain fatty acid and microbiota composition in a high-fat fructose-rich diet induced obese Göttingen Minipig model

An AX-enriched high DF diet improved the intestinal environment and attenuated protein fermentation, while protein did not show prebiotic effects.

Efficacy of medium-chain fatty acid salts distilled from coconut oil against two enteric pathogen challenges in weanling piglets

BACKGROUND

The search for alternatives to antibiotics in pig production has increased the interest in natural resources with antimicrobial properties, such as medium-chain fatty acids (MCFA) as in-feed additives. This study evaluated the potential of a novel blend of MCFA salts (DIC) from distilled coconut oil with a lauric acid content to reduce enteropathogens and control intestinal diseases around weaning. Two experimental disease models were implemented in early-weaned piglets, consisting of two oral challenges: Salmonella Typhimurium (1.2 × 108 CFU) or enterotoxigenic Escherichia coli (ETEC) F4 (1.5 × 109 CFU). The parameters assessed were: animal performance, clinical signs, pathogen excretion, intestinal fermentation, immune-inflammatory response, and intestinal morphology.

RESULTS

The Salmonella challenge promoted an acute course of diarrhea, with most of the parameters responding to the challenge, whereas the ETEC F4 challenge promoted a mild clinical course. A consistent antipathogenic effect of DIC was observed in both trials in the hindgut, with reductions in Salmonella spp. plate counts in the cecum (P = 0.03) on d 8 post-inoculation (PI) (Salmonella trial), and of enterobacteria and total coliform counts in the ileum and colon (P < 0.10) on d 8 PI (ETEC F4 trial). When analyzing the entire colonic microbiota (16S rRNA gene sequencing), this additive tended (P = 0.13) to reduce the Firmicutes/Bacteroidetes ratio and enriched Fibrobacteres after the Salmonella challenge. In the ETEC F4 challenge, DIC prompted structural changes in the ecosystem with increases in Dialister, and a trend (P = 0.14) to increase the Veillonellaceae family. Other parameters such as the intestinal fermentation products or serum pro-inflammatory mediators were not modified by DIC supplementation, nor were the histological parameters. Only the intraepithelial lymphocyte (IEL) counts were lowered by DIC in animals challenged with Salmonella (P = 0.07). With ETEC F4, the IEL counts were higher with DIC on d 8 PI (P = 0.08).

CONCLUSIONS

This study confirms the potential activity of this MCFA salts mixture to reduce intestinal colonization by opportunistic pathogens such as Salmonella or E. coli and its ability to modulate colonic microbiota. These changes could explain to some extent the local immune cell response at the ileal level.

Ensiled pulp from biorefining increased milk production in dairy cows compared with grass-clover silage

The objective of the current study was to examine the effect of fibrous pulp and partial substitution of soybean meal with green protein concentrate from biorefining of grass-clover on dry matter intake, milk production, digestibility, and eating behavior in dairy cows compared with untreated grass-clover silage and soybean meal. Biorefining of grass-clover occurred right after harvest in a production-scale twin-screw press. The twin-screw pressing separated the grass-clover into a pulp and a green juice. The green juice was fermented using lactic acid bacteria for protein precipitation and then decanted, and the precipitate was heat dried to constitute the green protein concentrate. From the same field, grass-clover was harvested 6 d later due to rainy weather and was prewilted before ensiling. The pulp and the grass-clover were ensiled in bales without additives. The production trial consisted of an incomplete 6 × 4 Latin square trial (3-wk periods; 12 wk total) including 36 lactating Holstein cows. The trial had 6 treatments in a 2 × 3 factorial design with 2 forage types (grass-clover silage and pulp silage) and 3 protein treatments (low protein, high protein with soybean meal, and high protein with a mixture of soybean meal and green protein). The trial was designed to test silage type, protein type, protein level, and the interaction between protein level and silage type. The forage:concentrate ratio was 55:45 in low protein total mixed rations (TMR) and 51:49 in high protein TMR. Low protein and high protein TMR were composed of 372 and 342 g/kg of DM of experimental silages, respectively, and green protein supplemented TMR was composed of 28.5 g/kg of DM of green protein. Silage type did not affect dry matter intake of cows. The average energy-corrected milk yield was 37.0 and 33.4 kg/d for cows fed pulp silage and grass-clover silage, respectively, resulting in an improved feed efficiency in the cows receiving pulp silage. Milk fat concentration was greater in milk from cows fed pulp silage, and milk protein concentration was lower compared with milk from cows fed grass-clover silage. The in vivo digestibility of crude protein and neutral detergent fiber was greater for pulp silage diets compared with grass-clover silage diets. Eating rate was greater, whereas daily eating duration was lower, for pulp silage diets compared with grass-clover silage diets. The partial substitution of soybean meal with green protein did not affect dry matter intake, milk yield, or eating behavior. The in vivo digestibility of crude protein in green protein supplemented diets was lower compared with soybean meal diets. The results imply that extraction of protein from grassland plants can increase the value of the fiber part of grassland plants.

Effect of dried oregano (Origanum vulgare L.) plant material in feed on methane production, rumen fermentation, nutrient digestibility, and milk fatty acid composition in dairy cows

Essential oils (EO) from oregano may have antimicrobial properties, potentially representing a methane mitigation strategy suitable for organic production. This study aimed to (1) examine the potential of oregano in lowering enteric methane production of dairy cows fed differing levels of dried oregano (Origanum vulgare ssp. hirtum) plant material containing high levels of EO; (2) determine whether differing levels of dried oregano plant material of another subspecies (Origanum vulgare ssp. vulgare) with naturally low levels of EO in feed affected enteric methane production; and (3) evaluate the effect of various levels of the 2 oregano subspecies (containing high or low levels of EO) in feed on rumen fermentation, nutrient digestibility, and milk fatty acids. Each experiment had a 4 × 4 Latin square design using 4 lactating Danish Holstein dairy cows that had rumen, duodenal, and ileal cannulas and were fed 4 different levels of oregano. Experiment 1 used low EO oregano [0.12% EO of oregano dry matter (DM)] and evaluated a control (C) diet with no oregano and 3 oregano diets with 18 (low; L), 36 (medium; M), and 53 g of oregano DM/kg of dietary DM (high; H). Experiment 2 used high EO oregano (4.21% EO of oregano DM) with 0, 7, 14, and 21 g of oregano DM/kg of dietary DM for C, L, M, and H, respectively. Oregano was added to the diets by substituting grass/clover silage on a DM basis. Low or high EO oregano in feed did not affect dry matter intake (DMI) or methane production (grams per day, grams per kilogram of DMI, grams per kilogram of energy-corrected milk, and percentage of gross energy intake). Rumen fermentation was slightly affected by diet in experiment 1, but was not affected by diet in experiment 2. In both experiments, the apparent total-tract digestibility of DM, organic matter, and neutral detergent fiber decreased linearly and cubically (a cubic response was not observed for neutral detergent fiber) with increasing dietary oregano content, while milk fatty acids were slightly affected. In conclusion, dried oregano plant material with either high or low levels of EO did not lower the methane production of dairy cows over 4 consecutive days, and no substantial effects were observed on rumen fermentation or nutrient digestibility. This conclusion regarding methane production is in contrast with literature and requires further study.

Response of gastrointestinal fermentative activity and colonic microbiota to protected sodium butyrate and protected sodium heptanoate in weaned piglets challenged with ETEC F4. Arch Anim Nutr 2019;73:339-359. [PMID: 31342760 DOI: 10.1080/1745039x.2019.1641376]

This study aimed to evaluate the potential of two new fat-protected butyrate or heptanoate salts to improve gut health and control post-weaning colibacillosis in weaning piglets challenged with enterotoxigenic Escherichia coli (ETEC) F4⁺, particularly focusing on their impact on intestinal microbiota and fermentative activity along the gastrointestinal tract (GIT). Seventy-two 21-d-old pigs were fed a plain diet (CTR) or supplemented with sodium butyrate (BUT) or sodium heptanoate (HPT), both at 0.3%. After a week of adaptation, animals were orally challenged at days 8 and 9 with 5.8 · 10⁹ and 6.6 · 10¹⁰ cfu, respectively, and were euthanised on d 4 and d 8 post-inoculation (PI) (n = 8) to collect blood, digesta and tissue samples and characterise microbial groups, pathogen loads (qPCR), fermentation, ileal histomorphometry and immune markers. Colonic microbiota was analysed by 16S rRNA gene MiSeq sequencing. Supplementing both acid salts did not compensate clinical challenge effects nor performance impairments and neither histomorphometry nor serum biomarkers. Changes in the gastric fermentative activity were registered, BUT reducing lactic acid concentrations (day 8 PI), and with HPT fewer animals presenting detectable concentrations of propionic, butyric and valeric acids. At ileum BUT increased acetic acid concentration (day 8 PI), and both additives reduced short-chain fatty acids (SCFA) in the colon. Increases in enterobacteria and coliforms counts in ileal digesta (day 4 PI, p < 0.10) and mucosa scrapes (p < 0.05) were registered although E. coli F4 gene copies were unaffected. Regarding changes in the colonic microbiota (day 4 PI), Prevotellaceae and Prevotella were promoted with BUT supplementation whereas only minor groups were modified in HPT-treated animals. Summarising, although the pathogen loads or inflammatory mediators remained unresponsive, butyrate and heptanoate showed a significant impact on microbial fermentation along the whole GIT, being able to modify different bacterial groups at the colon. It could be hypothesised that these effects might be mediated by a carry-over effect of the changes observed in gastric fermentation, but possibly also to a better nutrient digestion in the foregut as a result of the reduced colonic SCFA concentrations.

Mechanistic insight into the role of immunocastration on eliminating skatole in boars

The accumulation of skatole in fat tissue is one of the predominant factors, causing boar taint. The present study was aimed to understand the mechanism whereby active immunization against GnRH (immunocastration) eliminates skatole in boars. Thirty-six boars were assigned within litter into three groups (n = 12): control, surgically castrated, or immunized against GnRH at 10 wk of age (with a booster 8 wk later). Faecal and blood samples (for skatole and skatole-regulatory hormone profiles) were collected at 4-wk intervals until boars were slaughtered (26 weeks). Immunocastration reduced (P < 0.05) serum levels of androstenone, 17β-estradiol and IGF1 especially after the booster immunization, and down-regulated (P < 0.05) mRNA expressions of both IGF1 and IGF1receptor (IGF1R) in mucosa of ileum as well as colon at slaughter. Compared to intact controls, immunocastration substantially decreased (P < 0.05) faecal skatole contents subsequent to the decrease of serum IGF1 levels, which persisted in boars after surgical castration. In parallel with the decreased formation of skatole in the intestine, levels of skatole in serum and then in fat tissue were also decreased (P < 0.05). On the other hand, deprivation of testicular steroids, especially androstenone and 17β-estradiol accelerated skatole degradation metabolism in the liver by increasing (P < 0.05) hepatic CYP2E1, CYP2A, CYP2C49 and CYB5A expressions. Collectively, our results suggested that immunocastration decreased skatole formation in the intestine and meanwhile accelerated skatole degradation metabolism in the liver, resultantly eliminating skatole accumulation in male pigs. Decreased intestinal skatole formation by immunocastration appeared to be associated with the attenuated actions of IGF1 on the turnover of both ileal and colon mucosa.

Bifidobacterium bifidum ATCC 15696 and Bifidobacterium breve 24b Metabolic Interaction Based on 2'-O-Fucosyl-Lactose Studied in Steady-State Cultures in a Freter-Style Chemostat

Infants fed breast milk harbor a gut microbiota in which bifidobacteria are generally predominant. The metabolic interactions of bifidobacterial species need investigation because they may offer insight into the colonization of the gut in early life. Bifidobacterium bifidum ATCC 15696 hydrolyzes 2'-O-fucosyl-lactose (2FL; a major fucosylated human milk oligosaccharide) but does not use fucose released into the culture medium. However, fucose is a growth substrate for Bifidobacterium breve 24b, and both strains utilize lactose for growth. The provision of fucose and lactose by B. bifidum (the donor) allowing the growth of B. breve (the beneficiary) conforms to the concept of syntrophy, but both strains will compete for lactose to multiply. To determine the metabolic impact of this syntrophic/competitive relationship on the donor, the transcriptomes of B. bifidum were determined and compared in steady-state monoculture and coculture using transcriptome sequencing (RNA-seq) and reverse transcription-quantitative PCR (RT-qPCR). B. bifidum genes upregulated in coculture included those encoding alpha-l-fucosidase and carbohydrate transporters and those involved in energy production and conversion. B. bifidum abundance was the same in coculture as in monoculture, but B. breve dominated the coculture numerically. Cocultures during steady-state growth in 2FL medium produced mostly acetate with little lactate (acetate:lactate molar ratio, 8:1) compared to that in monobatch cultures containing lactose (2:1), which reflected the maintenance of steady-state cells in log-phase growth. Darwinian competition is an implicit feature of bacterial communities, but syntrophy is a phenomenon putatively based on cooperation. Our results suggest that the regulation of syntrophy, in addition to competition, may shape bacterial communities.IMPORTANCE This study addresses the microbiology and function of a natural ecosystem (the infant bowel) using in vitro experimentation with bacterial cultures maintained under controlled growth and environmental conditions. We studied the growth of bifidobacteria whose nutrition centered on the hydrolysis of a human milk oligosaccharide. The results revealed responses relating to metabolism occurring in a Bifidobacterium bifidum strain when it provided nutrients that allowed the growth of Bifidobacterium breve, and so discovered biochemical features of these bifidobacteria in relation to metabolic interaction in the shared environment. These kinds of experiments are essential in developing concepts of bifidobacterial ecology that relate to the development of the gut microbiota in early life.

The Mode of Action of Chicory Roots on Skatole Production in Entire Male Pigs Is neither via Reducing the Population of Skatole-Producing Bacteria nor via Increased Butyrate Production in the Hindgut

The effect of high levels of dietary chicory roots (25%) and intracecal exogenous butyrate infusion on skatole formation and gut microbiota was investigated in order to clarify the mechanisms underlying the known reducing effect of chicory roots on skatole production in entire male pigs. A Latin square design with 3 treatments (control, chicory, and butyrate), 3 periods, and 6 animals was carried out. Chicory roots showed the lowest numerical levels of skatole in both feces and plasma and butyrate infusion the highest. In the chicory group, an increased abundance of the skatole-producing bacterium Olsenella scatoligenes compared to the control group (P = 0.06), and a numerically higher relative abundance of Olsenella than for the control and butyrate groups, was observed. Regarding butyrate-producing bacteria, the chicory group had lower abundance of Roseburia but a numerically higher abundance of Megasphaera than the control group. Lower species richness was found in the chicory group than in the butyrate group. Moreover, beta diversity revealed that the chicory group formed a distinct cluster, whereas the control and butyrate groups clustered more closely to each other. The current data indicated that the skatole-reducing effect of chicory roots is neither via inhibition of cell apoptosis by butyrate nor via suppression of skatole-producing bacteria in the pig hindgut. Thus, the mode of action is most likely through increased microbial activity with a corresponding high incorporation of amino acids into bacterial biomass, and thereby suppressed conversion of tryptophan into skatole, as indicated in the literature.IMPORTANCE Castration is practiced to avoid the development of boar taint, which negatively affects the taste and odor of pork, and undesirable aggressive behavior. Due to animal welfare issues, alternatives to surgical castration are sought, though. Boar taint is a result of high concentrations of skatole and androstenone in back fat. Skatole is produced by microbial fermentation in the large intestine, and therefore, its production can be influenced by manipulation of the microbiota. Highly fermentable dietary fiber reduces skatole production. However, various theories have been proposed to explain the mode of action. In order to search for other alternatives, more efficient or less expensive, to reduce skatole via feeding, it is important to elucidate the mechanism behind the observed effect of highly fermentable dietary fiber on skatole. Our results indicate that highly fermentable dietary fiber does not affect skatole production by reducing the number of skatole-producing bacteria or stimulating butyrate production in the large intestine.

Changes in rumen bacterial and archaeal communities over the transition period in primiparous Holstein dairy cows

In the present study, we hypothesized that the rumen bacterial and archaeal communities would change significantly over the transition period of dairy cows, mainly as an adaptation to the classical use of low-grain prepartum and high-grain postpartum diets. Bacterial 16S rRNA gene amplicon sequencing of rumen samples from 10 primiparous Holstein dairy cows revealed no changes over the transition period in relative abundance of genera such as Ruminococcus, Butyrivibrio, Clostridium, Coprococcus, and Pseudobutyrivibrio. However, other dominant genus-level taxa, such as Prevotella, unclassified Ruminococcaceae, and unclassified Succinivibrionaceae, showed distinct changes in relative abundance from the prepartum to the postpartum period. Overall, we observed individual fluctuation patterns over the transition period for a range of bacterial taxa that, in some cases, were correlated with observed changes in the rumen short-chain fatty acids profile. Combined results from clone library and terminal-restriction fragment length polymorphism (T-RFLP) analyses, targeting the methyl-coenzyme M reductase α-subunit (mcrA) gene, revealed a methanogenic archaeal community dominated by the Methanobacteriales and Methanomassiliicoccales orders, particularly the genera Methanobrevibacter, Methanosphaera, and Methanomassiliicoccus. As observed for the bacterial community, the T-RFLP patterns showed significant shifts in methanogenic community composition over the transition period. Together, the composition of the rumen bacterial and archaeal communities exhibited changes in response to particularly the dietary changes of dairy cows over the transition period.

Development of a species-specific TaqMan-MGB real-time PCR assay to quantify Olsenella scatoligenes in pigs offered a chicory root-based diet

Olsenella scatoligenes is the only skatole-producing bacterium isolated from the pig gut. Skatole, produced from microbial degradation of l-tryptophan, is the main contributor to boar taint, an off-odor and off-flavor taint, released upon heating meat from some entire male pigs. An appropriate method for quantifying O. scatoligenes would help investigating the relationship between O. scatoligenes abundance and skatole concentration in the pig gut. Thus, the present study aimed at developing a TaqMan-MGB probe-based, species-specific qPCR assay for rapid quantification of O. scatoligenes. The use of a MGB probe allowed discriminating O. scatoligenes from other closely related species. Moreover, the assay allowed quantifying down to three target gene copies per PCR reaction using genomic DNA-constructed standards, or 1.5 × 10³ cells/g digesta, using O. scatoligenes-spiked digesta samples as reference standards. The developed assay was applied to assess the impact of dietary chicory roots on O. scatoligenes in the hindgut of pigs. Olsenella scatoligenes made up < 0.01% of the microbial population in the pig hindgut. Interestingly, the highest number of O. scatoligenes was found in young entire male pigs fed high levels of chicory roots. This indicates that the known effect of chicory roots for reducing skatole production is not by inhibiting the growth of this skatole-producing bacterium in the pig hindgut. Accordingly, the abundance of O. scatoligenes in the hindgut does not seem to be an appropriate indicator of boar taint. The present study is the first to describe a TaqMan-MGB probe qPCR assay for detection and quantification of O. scatoligenes in pigs.

Performance, nutrient utilization, and energy partitioning in broiler chickens offered high canola meal diets supplemented with multicomponent carbohydrase and mono-component protease

Two broiler chicken experiments were conducted to investigate the effects of canola meal (CM) replacing soybean meal (SBM) in diets supplemented with carbohydrase and protease on performance and partitioning of energy. First, a 2 × 2 × 2 factorial arrangement of treatments was employed to evaluate: protein meals (CM vs. SBM), carbohydrase (none or 300 mg/kg), protease (none or 200 mg/kg), and their interactions. Each treatment was fed to 6 replicated pens of 16 male broilers (Ross 308) from d 10 to 35. In the second experiment, 32 broiler chicks were used in a 2 × 2 factorial arrangement to investigate CM and carbohydrase effects on energy partitioning. Birds were transferred into 16 closed-circuit calorimeter chambers (4 chambers/diet; 2 birds/chamber) to measure heat production (HP), metabolizable and net energy (NE) by gaseous exchange, and total excreta collection from d 25 to 28. There were no 3-way interactions among experimental factors for any of the performance parameters measured. Birds given CM diets consumed less feed, had lower BW, and exhibited higher FCR compared to the control birds (P < 0.01). Both enzymes, alone or in combination, improved final BW and FCR (P < 0.05). There was an interaction between carbohydrase and protease for FCR over the grower period (P < 0.01), in which the combination of the enzymes resulted in further improvement of FCR. Energy, DM, and crude protein digestibility values were higher in control birds (P < 0.05). There was an interaction of protein meal and carbohydrase for HP, respiratory quotient (P < 0.05), and NE:ME ratio of the diets (P = 0.06). Inclusion of CM without carbohydrase increased HP and decreased NE and NE:ME ratio of the diets (P < 0.05). Carbohydrase decreased HP and increased retained energy (P = 0.06) and NE and NE:ME ratio (P < 0.05). In conclusion, high CM in the diet negatively affects growth performance through reduction in feed consumption, nutrient digestibility, and NE of the diet, which could partly be restored by enzyme supplementation.