Caecal Short-chain Fatty Acids Research Articles

The effect of increasing the level of oat hulls, extent of grinding and their interaction on the performance, gizzard characteristics and gut health of broiler chickens fed oat-based pelleted diets

The effect of ratio of oats with hulls (OWH) to dehulled oats (DO), extent of grinding, and their interaction on the performance, gizzard characteristics and intestinal health of broilers chickens were studied in this experiment. A total of 2860 one-day-old male broilers were allocated to 130 floor pens bedded with wood shavings and fed a starter diet until day 10. On day 11, the birds were randomly distributed among ten dietary treatments (13 replicates each), consisting of five oat-based pelleted diets with different proportion of OWH and DO, and with main ingredients either finely- (2 mm) or coarsely-ground (6 mm). Half of a batch of oats was thoroughly dehulled and half kept as is. The content of hulls (OH) in the DO and OWH was 1 and 224 g/kg, respectively. Using different OWH:DO ratios, the diets were formulated to contain 0, 29.5, 65.0, 96.0 and 114.0 g/kg OH. The ratio of ingredients to DO, and apparent metabolisable energy to protein (AME:CP) were kept constant for all diets. Birds and feed were weighed on day 11 and at termination on day 32. Increasing OH level did not affect weight gain (WG) from 11 to 32 days, but increased FCR linearly (P < 0.001). Although FI was not affected by the extent of grinding, FCR was significantly improved with fine grinding. Birds fed diets with highest OH level had a lower AME:WG compared to those given diets with DO only. Coarse grinding significantly increased gizzard dry matter (DM) weight which also increased linearly (P < 0.001) with increasing OH level. Coarse grinding as well as increasing OH level significantly improved gizzard and pancreas relative weights and decreased gizzard contents pH. Excreta DM contents and litter score were significantly improved with increasing OH level. Coarse grinding tended to (P = 0.069) reduce total eubacteria density in the ileum only at the highest OH level and tended to (P = 0.080) reduce Lactobacillus spp. density compared to fine grinding. Increasing OH level had no impact on caecal short chain fatty acids or lactic acid production, but it decreased indole concentration linearly (P = 0.026). Coarse grinding tended to increase (P = 0.053) caecal propionic acid production. Importantly, broiler chickens were able to handle an OWH-based diet and still maintained a similar WG compared to diets with DO only. A larger gizzard holding capacity and a faster passage of excess OH may explain the ability to increase FI in response to high OH dilution. The positive effect of OH on performance was more obvious when finely ground, but coarse components in the diets induce beneficial effects on intestinal microbiota.

Effect of two different dietary endo-1,4-β-xylanases on growth performance, intestinal histomorphology, caecal microbial population and short-chain fatty acid composition of broiler chickens

Effects of two different dietary xylanases on broiler performance and gut integrity were determined. Totally, 7600-d-old Ross-308 chicks were used for 41 d. Chicks were randomly assigned to 4 dietary treatments with 10 replicates (95 males, 95 females per replicate); they were: positive control (PC) based on Ross 308 nutrient specification; negative control (NC) with less ME (80 kcal/kg), crude protein and amino acids compared to PC; NC + AO with addition of xylanase derived from Aspergillus oryzae (AO); NC + TB with addition of xylanase derived from Trichoderma bisset (TB). Birds fed on PC diet significantly (p < 0.05) had higher final body weight (BW) and body weight gain (BWG) compared to other treatments. The final BWG and feed conversion ratio (FCR) were not fully compensated with the addition of the enzymes compared to PC, and FCR was found significantly (p < 0.05) higher in birds fed on diets NC + AO and NC + TB. However, dietary xylanase significantly improved FCR, villus surface area and total goblet cell number in NC + AO and NC + TB birds compared to NC. Xylanase supplementation significantly increased the concentrations of branched-chain fatty acid (BCFA) and total caecal short-chain fatty acid (SCFA) (p < 0.05). Furthermore, both xylanases increased lactobacillus count (p < 0.05). Dietary treatments had no effect on carcase parameters and mortality rate. In conclusion, along with improving performance parameters, the inclusion of xylanase enzymes with nutrient matrix value in broilers’ diet may ameliorate intestinal morphology, stimulate caecal microflora and increase caecal SCFA concentrations, but nutrient contribution of both enzymes seems overestimated.HIGHLIGHTSDietary xylanase could not compensate the final BWG and FCR compared to positive control.Dietary xylanase increased villus surface area and total goblet cell number.Dietary xylanase increased the concentrations of branched-chain fatty acids and total caecal short-chain fatty acid.

Toward Renewable-Based Prebiotics from Woody Biomass: Potential of Tailored Xylo-Oligosaccharides Obtained by Enzymatic Hydrolysis of Beechwood Xylan as a Prebiotic Feed Supplement for Young Broilers.

Although antibiotic resistance emerges naturally, this process has been accelerated by the worldwide overuse and misuse of antibiotics. It is essential to find effective alternatives in the broiler industry to improve poultry health while maintaining production efficiency and product safety. In this study, we aimed to evaluate a potential alternative: wood-derived xylo-oligosaccharides (XOS). The objective of this research was to investigate the potential of XOS prepared using enzymatic hydrolysis of beechwood xylan as a prebiotic feed supplement for broilers. A pilot study was conducted to explore the optimal XOS fraction profile by in vitro fermentation. Subsequently, a semi-continuous enzyme membrane reactor was used, allowing for the production of tailored XOS in large quantities. Given the strong bidirectional relationship between intestinal health, nutrition, and intestinal microbiota composition in broilers, an in vivo experiment was performed to explore the potential of XOS as a prebiotic feed supplement by investigating growth performance, feed conversion ratio, caecal short and medium chain fatty acid (SCFA and MCFA) concentration, and microbiological composition of the caecal content. Results from the pilot study indicated that higher enzyme concentrations in the hydrolysis process yield a product that leads to a higher total SCFA and MCFA- and butyric acid production during in vitro fermentation by caecal bacteria. Supplementation of the tailored XOS to the broiler diet (day 1 (d1)-d8 0.13% wt/wt XOS, d9-d15 0.32% XOS) resulted in higher Bifidobacterium counts, beneficial to the health of birds, on d11 and d15.

Ameliorative effect of peach gum on metabolic syndrome components and microbial short-chain fatty acids production in streptozotocin-induced rats

Peach gum (PG) contains a large number of polysaccharides and has hypolipidemic and anti-diabetic properties. Peach gum, specifically, may increase short-chain fatty acids (SCFAs), which modulate lipid, glucose, and insulin sensitivity and thus improve metabolic syndrome components (MetS). However, the mechanism remains unclear. This study aimed to reveal the effects of a whole PG intervention in ameliorating MetS conditions. Peach gum powder (PGP) was given in three dosages, comprised of PGP-L (210.64 mg), PGP-M (421.27 mg), and PGP-H (842.55 mg). Initially, PG was ground into powder (PGP). A total of five groups of Wistar rats were constituted. The healthy group was fed on a regular feeding (Comfeed AD II). MetS group was given a high-fat diet, a streptozotocin, and Nicotinamide injection. This study showed PGP significantly (p&lt;0.001) ameliorate the condition of HDL-C (187.70%), triglycerides (TG) (-33.40%), fasting blood glucose (FBG) (-69.80%), insulin sensitivity (60.38%), also caecal SCFAs (p&lt;0.05). It showed significant results of propionate and butyrate levels in the PHP-H group compared to the MetS group (p&lt;0.05). The results indicated that PG has a significant hypolipidemic effect, particularly in improving HDL-C levels, as well as antidiabetic effects in MetS-induced rats, which are supported by an increase in SCFAs. The improvement in MetS components (HDL, TG, FBG) has improved in all PGP groups.

Long-Term Dietary Fish Meal Substitution with the Black Soldier Fly Larval Meal Modifies the Caecal Microbiota and Microbial Pathway in Laying Hens.

Feeding laying hens with black soldier fly larval (BSFL) meal improves their performance. However, the beneficial mechanism of BSFL meals in improving the performance of laying hens remains unclear. This study investigated the effects of the BSFL diet on liver metabolism, gut physiology, and gut microbiota in laying hens. Eighty-seven Julia hens were randomly assigned to three groups based on their diets and fed maize grain-and soybean meal-based diets mixed with either 3% fish meal (control diet), 1.5% fish and 1.5% BSFL meals, or 3% BSFL meal for 52 weeks. No significant differences were observed in biochemical parameters, hepatic amino acid and saturated fatty acid contents, intestinal mucosal disaccharidase activity, and intestinal morphology between BSFL diet-fed and control diet-fed laying hens. However, the BSFL diet significantly increased the abundance of acetic and propionic acid-producing bacteria, caecal short-chain fatty acids, and modified the caecal microbial pathways that are associated with bile acid metabolism. These findings indicate that consuming a diet containing BSFL meal has minimal effects on plasma and liver nutritional metabolism in laying hens; however, it can alter the gut microbiota associated with short-chain fatty acid production as well as the microbial pathways involved in intestinal fat metabolism. In conclusion, this study provides evidence that BSFL can enhance enterocyte metabolism and gut homeostasis in laying hens.

Effects of supplementing organic- and inorganic-based selenium with vitamin E on intestinal histomorphology, caecal bacterial proliferation, and short-chain fatty acid profile in layer hens

The effects of supplementing different dietary selenium (Se) sources on intestinal histomorphology, caecal bacterial proliferation, and caecum short-chain fatty acid in layer chickens were studied. A total of 120 of 54-week-old Lohman Brown Classic laying hens were subjected to four dietary treatments: control group with no Se supplementation (T1), 0.3 mg/kg of sodium selenite (T2), 0.3 mg/kg of selenium yeast (T3), and 0.3 mg/kg of bacterial Se (Stenotrophomonas maltophilia, ADS18) (T4). All treatments were also supplemented with 250 mg/kg of vitamin E. Results showed significantly (p < 0.05) higher villus height in different small intestine parts in hens fed with diets containing organic Se sources (T3 and T4), as compared to inorganic sources (T2) and control (T1). A greater crypt depth was observed for the T1 group, as compared to T3 and T4 groups. The total bacterial populations of Bifidobacteria spp. and Lactobacilli spp. were significantly increased (p < 0.05), and tEscherichia coli population was significantly decreased (p < 0.05) in T3 and T4 groups. No effect on the total caecal short-chain fatty acid (SCFAs) content was observed. However, there was a significant increase (21.5%) of the butyric acid content in T4 group. In conclusion, organic Se supplementation, particularly bacterial organic Se, enhances intestinal histomorphology, increases the beneficial caecal bacterial proliferation, and increases butyric acid content.

Eggshell membrane modulates gut microbiota to prevent murine pre-cachexia through suppression of T helper cell differentiation.

BackgroundCachexia is a life‐threatening condition observed in several pathologies, such as cancer or chronic diseases. Interleukin 10 (Il10) gene transfer is known to improve cachexia by downregulating Il6. Here, we used an IL10‐knockout mouse model to simulate cachexia and investigate the effects of eggshell membrane (ESM), a resistant protein, on general pre‐cachexia symptoms, which is particularly important for the development of cachexia therapeutics.MethodsFive‐week‐old male C57BL6/J mice were fed an AIN‐93G powdered diet (WT), and 5‐week‐old male B6.129P2‐Il10 < tm1Cgn>/J (IL10−/−) mice were fed either the AIN‐93G diet (KO) or an 8% ESM‐containing diet (KOE) for 28 weeks. The tissue weight and levels of anaemia‐, blood glucose‐, lipid metabolism‐, and muscular and colonic inflammation‐related biochemical markers were measured. Transcriptomic analysis on liver and colon mucus and proteomic analysis on skeletal muscle were performed. Ingenuity Pathway Analysis was used to identify molecular pathways and networks. Caecal short‐chain fatty acids (SCFAs) were identified using HPLC, and caecal bacteria DNA were subjected to metagenomic analysis. Flow cytometry analysis was performed to measure the CD4+ IL17+ T cells in mesenteric lymph nodes.ResultsThe body weight, weight of gastrocnemius muscle and fat tissues, colon weight/length ratio, plasma HDL and NEFA, muscular PECAM‐1 levels (P < 0.01), plasma glucose and colonic mucosal myeloperoxidase activity (P < 0.05) and T helper (Th) 17 cell abundance (P = 0.071) were improved in KOE mice over KO mice. Proteomic analysis indicated the protective role of ESM in muscle weakness and maintenance of muscle formation (>1.5‐fold). Transcriptomic analysis revealed that ESM supplementation suppressed the LPS/IL1‐mediated inhibition of RXR function pathway in the liver and downregulated the colonic mucosal expression of chemokines and Th cell differentiation‐related markers (P < 0.01) by suppressing the upstream BATF pathway. Analysis of the intestinal microenvironment revealed that ESM supplementation ameliorated the microbial alpha diversity and the abundance of microbiota associated with the degree of inflammation (P < 0.05) and increased the level of total organic acids, particularly of SCFAs such as butyrate (2.3‐fold), which could inhibit Th1 and Th17 production.ConclusionsESM supplementation ameliorated the chief symptoms of cachexia, including anorexia, lean fat tissue mass, skeletal muscle wasting and reduced physical function. ESM also improved colon and skeletal muscle inflammation, lipid metabolism and microbial dysbiosis. These results along with the suppressed differentiation of Th cells could be associated with the beneficial intestinal microenvironment and, subsequently, attenuation of pre‐cachexia. Our findings provide insights into the potential of ESM in complementary interventions for pre‐cachexia prevention.

Low inclusion levels of Tenebrio molitor larvae meal in laying Japanese quail (Coturnix japonica, Gould, 1837) diet improve the intestinal morphometry, enzymatic activity and caecal short chain fatty acids profile

One hundred twenty, 12 weeks old laying Japanese quails (JQ) were equally divided into 4 groups (6 replicates of 5 birds/group). The control group (CON) fed a corn-soybean diet; TML1.4, TML2.8, and TML5.6 groups fed a diet where a Tenebrio molitor larvae meal (TML) was included at 1.4, 2.8, and 5.6%, respectively. The trial lasted 54 days. The villi height (VH) and the crypt depth (CD) linearly decreased from the control to the TML5.6 group (P < 0.01) in the duodenum, while an opposite trend was observed for the Ab+ mucous cells count (P < 0.01). The highest VH/CD ratio was found in the TML1.4 group (P < 0.01). In the jejunum a lower VH was observed in the TML1.4 compared to the CON group; the Ab+ mucous cells increased (P < 0.01) according to the increase of the TM inclusion in the diet, while the highest VH/CD ratio (P < 0.01) was recorded in the TML2.8 group. In the duodenum only the L-ANP has been affected by TML (P < 0.001), with a quadratic and linear effect. The L-ANP is affected by the dietary treatment in the jejunum (P < 0.05), where showed a quadratic effect with the highest value in TML2.8. The % of butyric acid is maximized (P < 0.05) with the TML1.4 diet and that of the isobutyrate and valeric acids increased (P < 0.01) from TML1.4 to TML5.6. The use of TML at 1.4% in laying quail diets can be considered as a way to improve the intestinal health of the birds.

Improving sorghum digestion in broilers by targeting fermentation of xylan.

This study was to examine if it is possible to accelerate sorghum digestion in broiler chickens by targeting fermentation of the xylan. Cobb 500 broilers (n = 960, 80 birds per treatment) were fed 12 sorghum-soybean meal-based dietary treatments fed as 3 phases (starter d 0 to 12, grower d 13 to 23, finisher d 24 to 35), with 8 replicate pens of 10 birds per treatment. For half of the treatments (n = 6), 10% of the sorghum in the diet was directly replaced with 10% wheat bran, as a source of fermentable fibre. The diets were supplemented with either 0, 50 or 2,000 mg/kg xylo-oligosaccharides (XOS), with or without xylanase application. Body weight gain (BWG), feed intake (FI) and feed conversion corrected for mortality (cFCR) was determined at d 0 to 35, and male and female body weight were measured on d 35. On d 35, ileum and caeca samples were collected from 2 birds per pen, for determination of caecal cellulase and xylanase activity, microbiota composition and short chain fatty acid (SCFA) concentration, and ileal XOS concentration. Supplementation with 2,000 mg/kg XOS caused increased BWG at d 0 to 35 (P = 0.007) and enhanced caecal propionic, valeric and succinic acid concentration (P < 0.05). Wheat bran increased FI (P = 0.018) and BWG (P = 0.016), as well as caecal Bifidobacteria concentration (P < 0.001). Ileal XOS concentration was greatest when feeding combined wheat bran, 2,000 mg/kg XOS, and xylanase, resulting in increased caecal total SCFA, acetic acid and butyric acid concentration, and xylanase and cellulase activity (P < 0.05). Results from this study present that feed efficiency in birds fed sorghum-based diets is improved as a consequence of supplementing with fermentable fibre, xylanase and XOS.

Low Inclusion Levels of Tenebrio Molitor Larvae Meal in Laying Japanese Quail (Coturnix Japonica, Gould, 1837) Diet Improve the Intestinal Morphometry, Enzymatic Activity and Caecal Short Chain Fatty Acids Profile

Low Inclusion Levels of Tenebrio Molitor Larvae Meal in Laying Japanese Quail (Coturnix Japonica, Gould, 1837) Diet Improve the Intestinal Morphometry, Enzymatic Activity and Caecal Short Chain Fatty Acids Profile

Perinatal transmission of a probiotic Bifidobacterium strain protects against early life stress-induced mood and gastrointestinal motility disorders.

Early life stress can considerably interfere in gut microbiome formation and nervous system development. Specific probiotic strains have been proved to exert anti-stress effects by modulating the gut-brain axis. However, little is known about whether probiotic treatment during pregnancy can protect the offspring from early life stress. In this study, Bifidobacterium breve CCFM1025, previously proven to exert microbial and neurobiological regulation effects, was given to pregnant mice. The offspring's gut and brain functions were evaluated when challenged with maternal separation. Intriguingly, treatment with probiotics during pregnancy protected the offspring from maternal separation-induced neurobiological and gastrointestinal disorders such as depression-like behaviour and delayed defecation. Quantification of CCFM1025 was performed, and perinatal transmission of CCFM1025 was further validated, which also explained the reason for increased levels of colonic 5-hydroxytryptamine and caecal short-chain fatty acids in the offspring. Our findings indicated that the effects of probiotics can be perinatally transmitted through gut microbes and that probiotic treatment during pregnancy may have great potential in managing health risks in early life.

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.

Performance indicators and gastrointestinal response of rabbits to dietary soybean meal replacement with silkworm pupae and mealworm larvae meals

ABSTRACT The objective of this study was to determine the effects of silkworm pupae meal (SPM) and mealworm larvae meal (MLM) on the production results and function of the digestive system in rabbits. Thirty male New Zealand White growing rabbits were divided into three feeding groups: control (C) (10% soybean meal [SBM] in the diet), group SPM (5% SBM and 4% SPM) and group MLM (5% SBM and 4% MLM). Compared with group C, rabbits of groups SPM and MLM, were characterised by higher final body weight and daily body weight gains. They were also found to have better apparent total tract digestibility (ATTD) of ether extract, and acid detergent fibre (ADF) and acid detergent lignin (ADL). Increased digesta viscosity was observed in these rabbits, as well as reduced extracellular activity of bacterial α-glucosidase, β-glucosidase, α-arabinofuranosidase and β-xylosidase in the caecal digesta. Similar differences between groups were also noted for the intracellular activity of β-glucuronidase, total activity of β-xylosidase and α-glucosidase. The SPM and MLM treatments contributed to an increase in the extracellular and total activity of N-acetyl-β-D-glucosaminidase (NAGase) in the caecal digesta. The SPM and MLM treatments were characterised by increased extracellular/total activity of colonic bacterial NAGase as well as increased release rates of NAGase and β-cellobiosidase, compared with group C. The rabbits fed the MLM diet had the lowest caecal concentrations of acetic acid, propionic acid, and total short chain fatty acids (SCFA). The proportion of butyric acid in the caecal SCFA profile was significantly lower in group MLM than in group C. The SPM treatment reduced the colonic concentration of iso-valeric acid. Group C had the highest colonic SCFA pool. It can be concluded that an inclusion of 4% SPM and 4% MLM in rabbit diets improved their production results, as well as beneficially increased the ATTD of fat, ADF and ADL without compromising the ATTD of other nutrients and energy. Although both dietary insect-derived products caused a mobilisation of microbiota to utilise of chitin (see NAGase activity), they stifled the metabolism of large intestinal microbiota, as manifested by decreased enzyme activity and lower SCFA concentrations.

Impact of combined xylanase and β-glucanase enzymes on digesta transit time, short-chain fatty acids, and caecal thermal profile of broilers fed corn–soy-based diets

A study was conducted to evaluate the effects of including a xylanase + β-glucanase enzyme product in corn–soy-based diets on performance, caecal short-chain fatty acids and thermal profile, ileal digestibility, and intestinal kinetics of broiler chickens. A total of 744 male day-old chicks were randomly allotted to 24 floor pens and distributed in a 2 × 2 factorial arrangement with low or standard energy level × without or with 100 g of the enzyme per ton of feed. Enzyme supplementation improved bodyweight gain from 1 to 21 d (P &lt; 0.05). An increased caecal concentration of acetic acid was observed when the enzyme was added to the low-energy diet (P &lt; 0.05). The pH of the caecal content was reduced (P &lt; 0.01), and the caecal temperature was increased by low-energy diets (P &lt; 0.05). The apparent ileal digestibility of energy was improved by the enzyme (P &lt; 0.01). The addition of the enzyme increased the mean retention time in the distal ileum (P &lt; 0.05). In summary, the addition of a xylanase + β-glucanase enzyme product in corn-based diets increases the retention time of digesta in the distal ileum and the caecal acetic acid concentration, improves ileal digestibility of energy and performance from 1 to 21 d in broiler chickens fed corn–soy-based diets.

Effects of Clostridium butyricum- and Bacillus spp.-Based Potential Probiotics on the Growth Performance, Intestinal Morphology, Immune Responses, and Caecal Microbiota in Broilers.

We aimed to investigate the effects of Clostridium butyricum-, Bacillus subtilis-, and Bacillus licheniformis-based potential probiotics on the growth performance, intestinal morphology, immune responses, and caecal short chain fatty acids (SCFAs) and microbial structure in broiler chickens. Three treatment groups containing a total of 1200 one-day-old AA broilers were included: birds fed with a basal diet only (Con), birds fed with added 1010 probiotics cfu/kg (ProL), and birds fed with added 1011 probiotics cfu/kg (ProH). The dietary probiotics significantly improved the final and average body weights and serum immunoglobulins A, M, and Y. The probiotics also enhanced the ileal morphology and improved the caecal acetate, butyrate, and propionate contents. Furthermore, 16S rRNA sequencing revealed that dietary compound probiotics modulated the caecal microflora composition as follows: (1) all birds shared 2794 observed taxonomic units; (2) treatment groups were well separated in the PCA and PCoA analysis; (3) the relative abundance of Parabacteroides, Ruminococcaceae_UCG-014, Barnesiella, Odoribacter, [Eubacterium_coprostanoligenes_group], [Ruminococcus]_torques_group, and Butyricimonas significantly varied between treatments. The compound probiotics improved the growth performance, serum immune responses, the ratio of ileal villus height to crypt depth, and major caecal SCFAs in broiler chickens. The dietary C. butyricum-, B. subtilis-, and B. licheniformis-based probiotics improved overall broiler health and would benefit the poultry industry.

Hulless barley and β-glucanase affect ileal digesta soluble beta-glucan molecular weight and digestive tract characteristics of coccidiosis-vaccinated broilers.

Exogenous β-glucanase (BGase) in barley-based feed has been shown to reduce digesta viscosity in chickens, and thereby improve performance. Less well studied is the potential for BGase to convert barley β-glucan into low molecular weight carbohydrates, which might influence digestive tract function and enteric disease. Coccidiosis-vaccinated broiler chickens were fed graded levels of hulless barley (HB) and BGase to determine their effects on β-glucan depolymerization and digestive tract characteristics. Broilers were fed high β-glucan HB (0%, 30% and 60% replacing wheat) and BGase (0%, 0.01% and 0.1%) in a 3 × 3 factorial arrangement. A total of 5,346 broilers were raised in litter floor pens and vaccinated for coccidiosis on d 5. Each treatment was assigned to 1 pen in each of 9 rooms. The significance level was set at P ≤ 0.05. At both 11 and 33 d of broiler ages, peak molecular weight of β-glucan in ileal digesta decreased with increasing BGase for 30% and 60% HB. The maximum molecular weight for the smallest 10% β-glucan molecules (MW-10%) decreased with BGase at both ages for 30% and 60% HB; for birds fed 0% HB, only 0.1% BGase decreased MW-10%. The 0.1% BGase increased caecal short chain fatty acids (SCFA) compared to the 0.01% BGase at d 11 only for the 60% HB. Ileal pH increased with increasing HB and BGase at d 11 and 33. Caecal pH was lower for 0.1% BGase than 0% BGase for 60% HB at d 11. Relative mRNA expression of interleukin 6 (IL-6) and IL-8 in the ileum increased with 0.1% BGase at d 11 and 33, respectively, whereas expression of ileal mucin 2 (MUC2) decreased with 0.1% BGase at d 33. In the caeca, interactions between HB and BGase were significant for monocarboxylate transporter 1 (MCT1) and mucin 5AC (MUC5AC) on d 11, but no treatment effects were found at d 33. In conclusion, BGase depolymerized high molecular weight β-glucan in HB in a dose-dependent manner. Hulless barley and BGase did not increase SCFA concentrations (except for 60% HB with 0.1% BGase at d 11) and caused minor effects on digestive tract histomorphological measurements and relative mRNA gene expression.

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.

Curcumin alleviates high-fat diet-induced hepatic steatosis and obesity in association with modulation of gut microbiota in mice

Curcumin (Cur) is a natural polyphenol with beneficial effect against obesity and related metabolic disorders, but its precise mechanisms of action remain to be defined due to its limited systemic bioavailability. We hypothesized that gut microbiota may be a prospective therapeutic target for Cur-induced metabolic benefits. This study aimed to investigate whether the metabolic adaptations resulting from Cur supplementation were mediated by the gut microbiota in high-fat diet (HFD)-fed obese mice. C57BL/6 mice were fed a control diet or a HFD diet with or without 0.2% Cur for 10 weeks. Lipid profiles, insulin sensitivity, hepatic metabolism, gut microbiota composition and short-chain fatty acid (SCFA) production were determined. Dietary Cur reduced fat mass, hepatic steatosis and circulating lipopolysaccharide levels and improved the insulin sensitivity in HFD-fed mice. More importantly, Cur supplementation modulated the gut microbiota composition and ameliorated intestinal dysbiosis by decreasing the ratio of Firmicutes/Bacteroidetes and endotoxin-producing Desulfovibrio bacteria and increasing the abundance of Akkermansia population and SCFA-producing bacteria, such as Bacteroides, Parabacteroides, Alistipes and Alloprevotella, along with increases in caecal and colonic SCFA concentrations. These dominant bacterial genera altered by Cur showed strong correlations with the obesity-related metabolic parameters in HFD-fed mice. In conclusion, our data suggest that Cur alleviated metabolic features of hepatic steatosis and insulin resistance in HFD-fed obese mice, which might be associated with the modulation of gut microbiota composition and metabolites.

Effect of rearing temperature on physiological measures and antioxidant status of broiler chickens fed stevia (Stevia rebaudiana B.) leaf meal and exogenous xylanase

• Rearing birds at high ambient temperature reduced feed intake but did not influence weight gain and feed efficiency. • Dietary xylanase increased hepatic vitamin E and stevia increased the hepatic carotenoid content in birds. • Incorporating stevia and xylanase into diets for broilers reared at high ambient temperatures reduces oxidative stress. The global climate is warming. Heat stress, as a result of high ambient temperatures, may negatively impact physiology and reduce growth performance of poultry. Stevia is a perennial shrub indigenous to South America where its phytochemical extracts have been used as a natural sweetener for hundreds of years. Its physiological effects, including antioxidant properties, on poultry are well known, however, the translation of these to improved growth performance is variable. Combining stevia with a commercial xylanase to enhance feed digestibility could therefore form a feeding strategy to partially mitigate the negative impact of rearing birds under high ambient temperatures. The study aimed to compare the growth performance, dietary energy and nutrient availability, oxidative status, gastrointestinal tract development, and caecal short chain fatty acid concentration; at two ambient rearing temperatures, when feeding diets containing stevia and exogenous xylanase, alone or in combination, to broiler chickens. Study design/Methods : Day-old chicks (n = 105) were reared in a single floor pen following breeder recommendations for the first 7 days, whereupon birds (n = 96) were randomly allocated to one of four experimental diets (negative control, stevia at 20 g/kg diet, xylanase at 100 FXU/kg diet, stevia at 20 g/kg diet + xylanase at 100 FXU/kg diet), in one of two environmental conditions (high ambient temperature at 32 ± 2 °C or regular rearing at breeder recommendations), in a 2 × 2 × 2 factorial design. Rearing birds at high ambient temperature reduced daily feed intake (p = 0.02). Birds fed stevia and reared at regular temperature had similar weight gain to birds reared in high ambient temperatures, although birds on the control diet housed at regular temperatures had the greatest weight gain (P < 0.05). Exogenous xylanase improved overall dietary metabolisable energy and improved nitrogen retention in the high ambient temperature group only (P < 0.05). Dietary stevia reduced caecal digesta butyric acid: acetic acid at regular temperature, but xylanase increased the butyric acid concentration at high ambient temperature (P < 0.05). Dietary stevia increased (P < 0.001) the hepatic carotenoid concentrations and xylanase improved (P < 0.05) hepatic vitamin E concentrations. Rearing temperature is an important environmental factor in broiler production. Exogenous xylanase supplementation can increase feed efficiency and dietary metabolisable energy. Feeding xylanase or stevia improves hepatic antioxidant status in broilers by increasing hepatic vitamin E and carotenoids, respectively, suggesting that either may be effective in counteracting oxidative stress.

Varying starch to fat ratios in pelleted diets: II. Effects on intestinal histomorphometry, Clostridium perfringens and short-chain fatty acids in Eimeria-challenged broiler chickens

ABSTRACT 1. The hypothesis behind the study was that a high dietary starch level (HS) would lead to impaired gut health compared to a low-starch diet (LS) in Eimeria-challenged broilers. The effects of two diets with different starch to fat ratios on intestinal histomorphometry, Clostridium perfringens counts and toxin profile, necrotic enteritis prevalence and abundance of short-chain fatty acids (SCFAs) were examined. 2. A total of 1,920 one-day-old Ross 308 broiler chickens were fed one of two isocaloric diets formulated either with high (32:1) or low (2:1) starch to fat ratios from d 10 to 29 of age. Each treatment group had 12 pen replicates containing 80 broilers each. On d 17, the chickens were challenged with Eimeria vaccine strains. Samples were collected on d 16, 21–23 and 29. 3. Whereas villus length increased gradually throughout the study in the HS group, a peak level was reached on d 21–23 in the LS group. On d 29, the HS group had significantly longer villi than the LS group. 4. Caecal SCFA concentrations were higher in the HS group compared to the LS group on d 16. In both groups, the SCFA level peaked on d 21–23, with the most pronounced increase seen in the LS group. 5. The C. perfringens netB:cpa ratio increased from d 16 to 29 in the HS group. C. perfringens counts and necrotic enteritis prevalence were similar between the two groups. 6. Diet affected the dynamics of small intestinal villus length and caecal SCFA abundance. These findings suggest that structural remodelling of the small intestine is an adaptation to different dietary starch levels, and that caecal SCFA abundance is associated with the availability of substrate for the microbiota in the posterior intestinal segments. Chickens adapted to higher levels of dietary starch might be more robust against Eimeria infections due to increased mucosal surface area. Studies with other dietary starch sources are required to clarify the impact of dietary starch levels on intestinal health in Eimeria–challenged broilers.