Cecal Bacteria Research Articles

Coated oregano essential oil and cinnamaldehyde compounds supplementation improves growth performance, enhances immune responses and inhibits cecal Escherichia coli proliferation of broilers.

Plant essential oils are unstable due to high volatility and easy oxidation, while microencapsulation provides a potentially effective strategy for increasing the stability of natural essential oils and preserving their function. This study examined the effects of feeding coated oregano essential oil and cinnamaldehyde (COEC) compounds on growth, immune organ development, intestinal morphology, mucosal immune function, and the cecal microbiota populations of broilers. Three hundred one-day-old male Arbor Acres broiler chicks were organized into five groups: (1) negative control fed basal diet alone (NC), (2) positive control receiving basal diet plus 50mg/kg of chlortetracycline (CTC), (3) basal diet plus 150mg/kg COEC (COEC150), (4) plus 300mg/kg COEC (COEC300), and (5) plus 450mg/kg COEC (COEC450). The supplement trial was continued for 42 days. The results showed that CTC, COEC300 and COEC450 treatments decreased the feed conversion ratio of broilers both in the starter and whole experiment phases, increased the height of jejunal villi at 21 d and the number of goblet cells and IgA-producing cells at 21 or 42 d compared with NC group (P < 0.05). Members of the COEC300 treatment group had a higher thymus weight index and jejunum length index than birds of NC or CTC groups at 21 d (P < 0.05). CTC and all COEC treatments decreased malondialdehyde content in jejunal mucosa at 42 d (P < 0.05). The population of Escherichia coli in the cecal digesta at 21 d was lower in the CTC, COEC300 and COEC450 treatment groups compared with the NC group (P < 0.05). In contrast to the CTC group, COEC supplementation dose-dependently accelerated body weight gain, improved jejunal morphology, decreased malondialdehyde content in jejunal mucosa, increased numbers of jejunal goblet cells and IgA-producing cells, and decreased the Escherichia coli population in cecal digesta at 21 or 42 d (P < 0.05). Thus, we concluded that feeding broiler chickens with 300 or 450mg/kg in antibiotic-free diets can improve growth performance, enhance immune responses and inhibit the proliferation of cecal pathogenic bacteria.

Effects of xylo-oligosaccharide supplementation on the production performance, intestinal morphology, cecal short-chain fatty acid levels, and gut microbiota of laying hens

This study investigated the effects of xylo-oligosaccharide supplementation on the production performance, intestinal morphology, cecal short-chain fatty acid levels, and gut microbiota of laying hens. A total of 800 Lohmann pink layers, each 48 wk old, were randomly divided into 5 dietary treatment groups, namely XOS at 0 (CON), 100 (XOS1), 200 (XOS2), 300 (XOS3) and 400 (X0S4) mg/kg. The experimental period was 24 wk. The results revealed that the egg production rate and the number of eggs laid by each layer between 1 to 12 wk increased as the XOS concentration increased (Plinear < 0.05). The sand-shell egg percentage decreased significantly from 1 to 12 wk in the XOS1, XOS2, and XOS3 groups (PANOVA < 0.05). Compared with the CON group, the 4 XOS dosage groups presented significant increases in the villus height and the ratio of villus height to crypt depth in the jejunum (PANOVA < 0.05), whereas a linear decrease in jejunal crypt depth (Plinear < 0.05) was noted. In addition, XOS supplementation significantly increased the concentrations of butyric acid and isovaleric acid in the caeca (PANOVA < 0.05). High-throughput sequencing analysis of bacterial 16S rRNA revealed that dietary XOS supplementation influenced the cecal microbiota. The alpha diversity analysis indicated that the richness of cecal bacteria was greater in the laying hens fed XOS. The modulation of the cecal microbiota composition upon the addition of XOS was characterized by an increased abundance of Firmicutes and Bifidobacteriaceae, and decreased abundance of Bacteroidetes. At the genus level, dietary XOS supplementation resulted in decreases in the abundances of Bacteroides and Rikenellaceae_RC9_gut_group and an increase in the abundance of Lactobacillus. In conclusion, dietary XOS supplementation improved the production performance of laying hens by increasing the production of short-chain fatty acids and improving their intestinal morphology, which was achieved mainly through changes in the composition of the intestinal microbiota. The recommended level of XOS in the diet of laying hens is 200 mg/kg.

PSVI-19 Abundance of some cecal bacteria in Lohmann LSL lite pullets and hens fed omega-3 fatty acids and yeast bioactives in low or high spacing allowance

Abstract Nutritional optimizations and rearing environment that meets welfare standards are prerequisite in the performance and health of laying hens. Rearing practices influence gastrointestinal development, microbiota, and immune function. However, little is known on the implications of rearing spacing allowance (SA) and feed ingredients on intestinal microbiota. We determined the abundance of selected cecal bacteria in pullets and hens in response to rearing SA and dietary omega-3 fatty acids (N-3 FA) and yeast bioactive (YB) from placement to 17 wk of age (woa). One-day old chicks (n = 2,632) were placed in cages in 2 SA of 24 cages each: High SA (HSA, 348 cm2/bird; ~50 birds/cage) and Low SA (LSA, 284 cm2/bird; ~68 birds/cage). Birds were fed corn and soybean-based diets (C), C + 3% co-extruded full fat flaxseed and pulse mixture (N-3 FA) and C + 0.05% YB processed with β-1,3-glucan hydrolase (YB). Birds were allocated to diets within SA according to 2 x 3 factorial design (n = 8 cage/treatment) and fed ad libitum. At 4 and 16 woa, 1 and 2 pullets/treatment respectively, were necropsied for ceca digesta from each cage and independently analyzed. At 18 woa, hens were placed in enriched cages based on rearing treatment identities in egg production facility and fed a commercial diet. At 35 woa, 18 hens per treatment were necropsied for ceca digesta samples and analyzed independently. Samples were analyzed for viable bacterial counts for E. coli, Enterococcus and Lactobacillus. Statistical analysis was performed by general linear mixed model procedures of SAS with diets, SA, sampling age and associated interactions as fixed factors, difference with P &amp;lt; 0.05 was considered significant. Comparison of log-transformed means (CFU/g) showed that diets and SA had no significant effect on cecal E. coli counts at 4, 8 and 35 woa (P &amp;gt; 0.05; Table 1). However, at 16 woa the least E. coli counts was found in LSA (P &amp;lt; 0.0001), with N-3-FA-fed and YB-fed pullets having fewer numbers (P = 0.007) than control-fed pullets. There was no interaction effects between diet and density for E. coli in all sampling wk (P &amp;gt;0.05). No significant effect of SA or diets were observed at any sampling week for Enterococcus counts, except LSA had a tendency at 8 woa (P = 0.078). At 8 woa, the cecal Lactobacillus counts (P = 0.009) were less in LSA relative to HSA pullets. In conclusion, feeding of N3-FA or YB during rearing influenced cecal microbiota. Supplementation of YB seemed to promote growth of beneficial Lactobacillus, which is associated with strengthened immunity.

The anticoccidial effects of probiotics and prebiotics on the live coccidia vaccine and the subsequent influence on poultry performance post-challenge with mixed Eimeria species

Live vaccines containing Eimeria oocysts are commercially available to protect against avian coccidiosis. Additionally, probiotics (PRO) and prebiotics (PRE) improve the poultry productivity and health and can be used as anticoccidial substitutes. However, the impact of PRO and PRE on reproductive potential, lesion score, intestinal health, and immunization outcomes of the live coccidia vaccines has not received adequate attention. Five groups of unsexed 1-day-old broiler chicks were used as follows: negative control (NC); challenged control (CC); vaccinated and challenged (VC); vaccinated, PRO-treated, and challenged (V-PRO); and vaccinated, PRE-treated, and challenged (V-PRE). At 21 d post-vaccination (pv), the vaccine increased the count of cecal anaerobes (P ≤ 0.05) and coliforms (P > 0.05) as well as harmed body weight gain (WG) (P ≤ 0.05), cecal lactic acid bacteria (P ≤ 0.05), and plasma carotenoid level (P > 0.05). None of the additives decreased oocyst shedding after vaccination, although they lowered the middle intestine and cecal lesion scores (P > 0.05). Compared to VC (2.68 ± 0.12) and V-PRE (2.66 ± 0.05), the V-PRO group showed an improved carotenoid level pv (2.96 ± 0.05) (P ≤ 0.05). V-PRE exhibited higher WG (822.95 ± 18.25) (P > 0.05) and FI (1153.01 ± 10.02) (P ≤ 0.05) than VC (781.86 ± 25.16 and 1109.85 ± 33.68) and V-PRO pv (787.61 ± 19.92 and 1077.43 ± 15.99). Following the homologous coccidia challenge, coccidia-vaccinated broilers adminstered the PRO or PRE continued to exhibit protection levels comparable to those received the vaccine alone. During 2 weeks post-challenge, VC, V-PRO and V-PRE improved bird performance and reduced oocyst shedding and lesion scores compared to CC. Ultimately, PRO and PRE treatments did not significantly reverse the reduction in growth performance in broiler chickens vaccinated against coccidia during the 1st three weeks of age.

Effects of Moringa oleifera Leaf Powder on the Growth Performance, Meat Quality, Blood Parameters, and Cecal Bacteria of Broilers.

The effect of dietary inclusion of Moringa oleifera leaf powder (MLP) on the growth, meat quality, carcass characteristics, hematobiochemical profile, and cecal bacteria of broiler chicken was investigated in this research trial. In this study, 192-day-old Arbor Acre broiler chicks were assigned in a completely randomized design to three groups: control, antibiotic, and MLP. A standard basal diet was given to the control group, while the antibiotic group received 75 mg/kg chlortetracycline, and the MLP group received 100 mg/kg M. oleifera leaf powder supplemented basal diet. Each group was further divided into eight replicates consisting of eight birds each, and the trial ran for 35 days. Among the groups, the MLP-fed broilers achieved the highest final body weight (FBW), average daily gain (ADG), and average daily feed intake (ADFI). Notably, the FCR for the whole experimental period was lower in the MLP group, indicating a more efficient use of feed for growth. Supplementation of MLP with basal diet significantly increased (p < 0.05) the weight of thighs and drumsticks relative to live weight %, while the spleen and abdominal fat weight (% of live weight) were significantly decreased (p < 0.05). Adding MLP to the diet improved the meat quality of broilers, as indicated by the highest pH of meat at 45 min and the lowest cooking loss (%) observed in this group. MLP exhibited hypocholesterolemic and hypolipidemic effects, with the lowest total cholesterol and triglyceride levels compared to non-supplemented groups. The hematological profile revealed that the MLP group exhibited the highest RBC count and Hb level, while also showing the lowest H/L ratio. Moringa supplementation significantly (p < 0.05) modulated the cecal bacterial population, reducing pathogenic E. coli and Shigella spp. while increasing beneficial Lactobacillus spp. and the total aerobic plate count (TAPC). In conclusion, Moringa oleifera leaf powder (MLP) can be used as a natural feed supplement for promoting the growth, meat quality, healthy blood, and sound health of broilers.

Effects of oregano and/or rosemary extracts on growth performance, digestive enzyme activities, cecal bacteria, tight junction proteins, and antioxidants-related genes in heat-stressed broiler chickens

The study examined the impact of adding oregano extract and/or rosemary to broiler diets to counteract the growth inhibition caused by heat stress (HS). It also investigated the effects on the activity of digestive enzymes, microbiological composition, and the expression of antioxidant and tight junction-related proteins. Three hundred- and fifty-day-old male broilers, were randomly assigned to 7 treatment groups, with each group comprising 5 replicates, and each replicate containing 10 chicks in a cage. The diets were: 1) a basal diet, 2) a diet supplemented with 50 mg/kg of rosemary, 3) a diet supplemented with 100 mg/kg of rosemary, 4) a diet supplemented with 50 mg/kg of oregano, 5) a diet supplemented with 100 mg/kg of oregano, 6) a combination diet containing 50 mg/kg each of rosemary and oregano, and 7) a combination diet containing 100 mg/kg each of rosemary and oregano. Dietary oregano extract enhanced the growth and feed utilization of heat-stressed birds, especially at a concentration of 50 mg/kg. Moreover, oregano extract improved jejunal protease and amylase activities. The extracts of rosemary and oregano significantly reduced IgG and IgM levels. Dietary 50 mg oregano extract significantly upregulated intestinal integrity-related genes including jejunal CLDNI, ZO-1, ZO-2, and MUC2. Dietary 50 mg oregano extract significantly downregulated hepatic NADPH oxidase 4 (NOX4) and nitric oxide synthase 2 (NOS2) expressions. Our results suggest that incorporating oregano leaf extract into the diet at a concentration of 50 mg/kg improves the growth performance of broilers exposed to heat stress. This improvement could be attributed to enhanced gut health and the modulation of genes associated with oxidative stress and tight junction proteins.

Nutraceuticals vs. antibiotic growth promoters: differential impacts on performance, meat quality, blood lipids, cecal microbiota, and organ histomorphology of broiler chicken

The main goal of this study was to evaluate the effect of nutraceuticals vs. in-feed antibiotics on performance, blood lipids, antioxidant capacity, cecal microbiota, and organ histomorphology of broiler chickens. A total of 320 one-day-old male broiler chickens were distributed into 5 treatment groups with 8 replicates each. The control group was fed on a basal diet without any additives (NC); the antibiotic group was fed on a basal diet supplemented with 100 mg kg-1 avilamycin (PC); the algal group was fed on a basal diet supplemented with a mixture of Spirulina platensis and Chlorella vulgaris (1.5 g + 1.5 g/kg feed) (SP+CV); the essential oil group was fed with a basal diet containing 300 mg/kg feed rosemary oil (REO); and the probiotics group (a mixture of 1 × 1011 CFU/g Bacillus licheniformis, 1 × 1011 CFU/g Enterococcus facieum, 1 × 1010 CFU/g Lactobacillus acidophilus, and 2 × 108 CFU /g Saccharomyces cerevisiae) was fed with a basal diet supplemented with 0.05% probiotics (PRO). The experiment lasted for 35 d. A beneficial effect of SP+CV and PRO (P < 0.01) was noticed on final body weight, body weight gain, feed conversion ratio, and breast yield. The dietary supplementation with SP+CV, REO, and PRO increased (P < 0.001) broilers' cecal lactic acid bacteria count compared to the control. Lower cecal Clostridium perfringens and Coliform counts (P < 0.001) were noticed in chickens fed the PC and supplemental diets. Malondialdehyde (MDA) concentration was decreased, while glutathione peroxidase (GPx), superoxide dismutase, and catalase enzymes were increased in the breast and thigh meat (P < 0.001) of broiler chickens fed SP+CV, REO, and PRO diets. Dietary SP+CV, REO, and PRO supplementation decreased (P < 0.001) serum total lipids, cholesterol, triglycerides, low-density lipoprotein, and MDA, but increased serum high-density lipoprotein and GPx compared to PC and NC. No pathological lesions were noticed in the liver, kidney, or breast muscle among broilers. The SP+CV, REO, and PRO groups had greater (P < 0.001) intestinal villi height and crypt depth while lower goblet cell densities (P < 0.01) than the control. The present findings suggest that PRO and SP+CV, followed by REO could be suitable alternatives to in-feed antibiotics for enhancing the performance, health, and meat quality of broiler chickens.

INFLAMMATORY RESPONSES TO POLYMICROBIAL INTRA-ABDOMINAL SEPSIS ARE HIGHLY VARIABLE BUT STRONGLY CORRELATED TO ENTEROBACTERIACEAE OUTGROWTH.

Sepsis is a common, heterogeneous, and frequently lethal condition of organ dysfunction and immune dysregulation due to infection. The causes of its heterogeneity, including the contribution of the pathogen, remain unknown. Using cecal slurry, a widely used murine model of intraperitoneal polymicrobial sepsis, as well as 16S ribosomal RNA sequencing and measurement of immune markers, we performed a series of translational analyses to determine whether microbial variation in cecal slurry composition (representing intra-abdominal pathogens) mediated variation in septic response. We found wide variation in cecal slurry community composition that changed markedly over the 24-h course of infection. This variation in cecal slurry bacteria led to large variation in physiologic and inflammatory responses. Severity of inflammatory response was positively correlated with intraperitoneal enrichment with Enterobacteriaceae. Likewise, in a human cohort of patients with intra-abdominal abscesses, Enterobacteriaceae was also associated with increased inflammatory markers. Taken together, these data demonstrate that intra-abdominal Enterobacteriaceae drives inflammation in sepsis both in animal models and human subjects. More broadly, our results demonstrate that pathogen identity is a major driver of the host response in polymicrobial sepsis and should not be overlooked as a major source of phenotypic heterogeneity.

Physiological responses and intestinal conditions of broiler chickens treated with encapsulated Acalypha australis L. leaf extract and chitosan.

The ban on antibiotic growth promoters adversely affects the physiological condition and health of poultry. The aim of this study was to determine the effect of encapsulated Acalypha australis L. leaf extract, chitosan, or a combination of both on the physiological and intestinal conditions of broiler chickens. A total of 280 Cobb broiler chicks were randomly distributed into four groups: Basal feed without additives (CNTL), basal feed with 0.01% encapsulated A. australis leaf extract (EALE), 0.01% chitosan (CHIT), and 0.01% EALE and 0.01% chitosan (EACH). Sample collection and data measurement were conducted on day 36. There was a tendency (p = 0.08) for EACH bird to have a higher body weight than the other groups. Feed consumption was higher (p < 0.05) in EACH than in EALE and CHIT. Feed conversion ratio (FCR) was lower (p < 0.05) in EALE, CHIT, and EACH than in CNTL. Erythrocyte numbers were lower (p < 0.05) in EALE than in CNTL and EACH. Hematocrit was lower (p < 0.05) in EALE and CHIT groups than in the other two groups. There was a tendency (p = 0.09) for heterophils to be higher in EACH than in CNTL. Thrombocyte counts were lower (p < 0.05) in EACH group than in the other groups. Serum globulin levels were higher (p < 0.05) in EACH than in CNTL and CHIT. The albumin-to-globulin ratio was higher (p < 0.05) in CNTL than in EALE and EACH. Coliform bacteria tended to be lower (p = 0.05) in the cecum of EACH broilers than that of other broilers. Similarly, the ratio of Lactic acid bacteria to coliforms tended to be higher (p = 0.08) in the cecum of EACH group than that in the other groups. Treatments did not influence the intestinal morphology of broiler chickens (p > 0.05). A combination of EALE and chitosan as feed additives enhanced the final body weight and feed efficiency (FCR) of broilers. These additives also increased the levels of heterophils, serum globulin, the ratio of LAB to coliforms, and reduced thrombocytes, albumin-to-globulin ratio, and cecal coliform bacteria. Hence, EALE and chitosan blend improved the growth performance, immune status, and intestinal health of broiler chickens.

Effects of adding bile acids to dietary storage japonica brown rice on growth performance, meat quality, and intestinal microbiota of growing-finishing Min pigs.

This study investigated the effects of storage japonica brown rice (SJBR) and bile acids (BA) on the growth performance, meat quality, and intestinal microbiota of growing-finishing Min pigs. A total of 24 healthy Min pigs with a similar body weight of 42.25 ± 2.13 kg were randomly divided into three groups with eight replicates of one pig each. The groups were as follows: CON (50% corn), SJBR (25% corn +25% SJBR), and SJBR + BA (25% corn +25% SJBR +0.025% hyodeoxycholic acid). The experimental period lasted from day 90 (the end of the nursery phase) to day 210 (the end of the finishing phase). The results showed the following: (1) Compared with the CON group, there was no significant difference in the average daily gain (ADG) and average daily feed intake (ADFI) of the SJBR and SJBR + BA groups, and the feed conversion ratio (FCR) was significantly decreased (p < 0.05). (2) Compared with the CON group, the total protein (TP) content in the serum was significantly increased, and the blood urea nitrogen (BUN) content was significantly decreased (p < 0.05) in the SJBR and SJBR + BA groups; moreover, HDL-C was significantly higher by 35% (p < 0.05) in the SJBR + BA group. (3) There were no significant differences in carcass weight, carcass length, pH, drip loss, cooking loss, and shear force among the groups; the eye muscle area was significantly increased in the SJBR group compared with the CON group (p < 0.05); back fat thickness was significantly decreased in the SJBR + BA group compared with the SJBR group (p < 0.05); and the addition of SJBR significantly increased the mRNA expression of MyHC I in the longissimus dorsi (LD) muscle of growing-finishing Min pigs (p < 0.05). (4) The cecal bacteria were detected using 16S rDNA, and the proportion of Lactobacillus was increased gradually at the genus level, but there was no significant difference among the different groups. In conclusion, 25% SJBR can improve the growth performance and increase the abundance of intestinal beneficial bacteria, and based on this, adding bile acids can reduce the back fat thickness of growing-finishing Min pigs.

Laying hen responses to multi-strain Bacillus-based probiotic supplementation from 25 to 37 weeks of age.

This study aimed to investigate the efficacy of Bacillus-based probiotics supplemented at two different levels to modulate the productive performance, egg quality, tibia traits, and specific cecal bacteria counts of Hy-Line Brown layers from 25 to 37 weeks of age. A total of 216 twenty-five-week-old hens were randomly distributed into 3 experimental diets with 12 replicates of 6 birds per cage. Diets included basal diet supplemented with 0 (CON), 3×108 (PRO1), or 3×109 (PRO2) colony-forming unit (CFU) of the test probiotic containing Bacillus subtilis PB6, Bacillus subtilis FXA, and Bacillus licheniformis G3 per kilogram of feed. Improved egg weights and mass at 29 weeks; and feed intake at 31 weeks (p<0.10) were noticed with the probiotic-supplemented PRO1 and PRO2 diets. Considering egg quality, the shell thickness, Haugh units, and yolk color were improved; but yolk cholesterol was lowered (p<0.05) with PRO1 and PRO2 diets at 29 weeks. At both 33 and 37 weeks, the egg-breaking strength, shell color and thickness, albumen height, Haugh units, and yolk color were improved; but yolk cholesterol was similarly lowered (p<0.05) with the PRO1 and PRO2 diets. Improved tibia Ca, ash, weights, and density; and raised cecal counts of Bifidobacteria and Lactobacilli (p<0.05) were noticed with PRO1 and PRO2 diets. Improved tibia P but reduced Clostridia counts (p<0.10) were also observed with the PRO1 and PRO2 diets. Probiotic supplementation of Bacillus subtilis PB6, Bacillus subtilis FXA, and Bacillus licheniformis G3 at 3×108 CFU/kg of feed is adequate to significantly improve egg quality, lower yolk cholesterol, enhance several tibia traits, and raise the populations of beneficial cecal bacteria. Modest improvements in several productive parameters and tibia P but reduced Clostridia were also observed; and could warrant further investigation of probiotic effects beyond the current test period.

Effects of microencapsulated essential oils and organic acids preparation on growth performance, slaughter characteristics, nutrient digestibility and intestinal microenvironment of broiler chickens

To develop effective antibiotics alternatives is getting more and more important to poultry healthy production. The study investigated the effects of a microencapsulated essential oils and organic acids preparation (EOA) on growth performance, slaughter performance, nutrient digestibility and intestinal microenvironment of broilers. A total of 624 1-day-old male Arbor Acres broilers were randomly divided into 6 groups including the control group (T1) fed with basal diet, the antibiotic group (T2) supplemented with basal diet with 45 mg/kg bacitracin methylene disalicylate (BMD), and four inclusion levels of EOA-treated groups (T3, T4, T5, T6 groups) chickens given basal diet with 200, 400, 600 and 800 mg EOA/kg of diet, respectively. Results showed that compared with the control, the 200 mg/kg EOA group increased average daily gain (ADG) and average body weight (ABW) during the early stage (P < 0.05). EOA addition decreased crypt depth of the ileum (P < 0.05), but villus height to crypt depth ratio was increased by EOA addition at 200 and 400 mg/kg at d 21 (P < 0.05). Compared with the control, dietary addition EOA at 200, 400 and 600 mg/kg increased the lipase activity in the duodenum at d 21 (P < 0.05). Increased lactic acid bacteria population was found in cecal digesta of the 400 mg/kg EOA group at d 21 (P < 0.05), and higher concentration of butyric acid level was observed in cecal digesta at d 21 and d 42 in the 200 mg/kg EOA group compared with the control (P < 0.05). RT-PCR analysis found that dietary EOA addition decreased the gene expression of IL-1β, COX-2 and TGF-β4 in the ileum at d 21 (P < 0.05), while only the 200 mg/kg EOA increased the gene expression of IL-10, TGF-β4, Claudin-1, ZO-1, CATH-1, CATH-3, AvBD-1, AvBD-9 and AvBD-12 in the ileum at d 42 (P < 0.05) compared with the control. In summary, adding 200 mg/kg and 400 mg/kg of the EOA to the diet could improve the growth performance and intestinal microenvironment through improving intestinal morphology, increasing digestive enzymes activity and cecal lactic acid bacteria abundance and butyric acid content, improving intestinal barrier function as well as maintaining intestinal immune homeostasis. The improving effect induced by EOA addition in the early growth stage was better than that in the later growth stage. Overall, the EOA product might be an effective antibiotic alternative for broiler industry.

The effects of ambient temperature and feeding regimens on cecum bacteria composition and circadian rhythm in growing rabbits.

Seasonal environmental shifts and improper eating habits are the important causes of diarrhea in children and growing animals. Whether adjusting feeding time at varying temperatures can modify cecal bacterial structure and improve diarrhea remains unknown. Three batches growing rabbits with two groups per batch were raised under different feeding regimens (fed at daytime vs. nighttime) in spring, summer and winter separately, and contents were collected at six time points in 1 day and used 16S rRNA sequencing to investigate the effects of feeding regimens and season on the composition and circadian rhythms of cecum bacteria. Randomized forest regression screened 12 genera that were significantly associated with seasonal ambient temperature changes. Nighttime feeding reduced the abundance of the conditionally pathogenic bacteria Desulfovibrio and Alistipes in summer and Campylobacter in winter. And also increases the circadian rhythmic Amplicon Sequence Variants in the cecum, enhancing the rhythm of bacterial metabolic activity. This rhythmic metabolic profile of cecum bacteria may be conducive to the digestion and absorption of nutrients in the host cecum. In addition, this study has identified 9 genera that were affected by the combination of seasons and feeding time. In general, we found that seasons and feeding time and their combinations affect cecum composition and circadian rhythms, and that daytime feeding during summer and winter disrupts the balance of cecum bacteria of growing rabbits, which may adversely affect cecum health and induce diarrhea risk.

Gut microbiome and serum metabolome analyses identify Bacteroides fragilis as regulators of serotonin content and PRL secretion in broody geese

Broody behavior is regulated by hypothalamic prolactin secretion, which seriously affects egg production in poulty production. Numerous studies have provided evidence that animal behavior is governed by dynamic bidirectional communication between specific gut bacteria and their host via the brain–gut–microbiome axis. However, little research focused on how the gut microbiota influence broody behavior in poultry. In this study, Zhedong white geese in laying and brooding phases were selected. Ten differentially abundant bacteria in cecum were detected between brooding and laying geese through metagenomic analyses and 16S rRNA sequencing (P<0.05), and Bacteroides fragilis was specifically identified as a key driver species in the brooding geese. Moverover, the serum metabolites were quantified, and the 313 differentially abundant metabolites were found between the two groups of different physiological geese. They were primarily enriched in the tryptophan metabolism pathways. Pearson correlation analyses revealed there was a significant positive correlation between B. fragilis abundance and the context of 11 tryptophan metabolism-related metabolites (such as serotonin, etc.) in broody geese, which hinted that those tryptophan metabolites might be produced or driven by B. fragilis. Finally, the serum hormone levels were also measured. We found there was a positive correlation between B. fragilis abundance and content of serotonin. Besides, prolactin secreted by the pituitary gland was greater in brooding geese than that in laying geese, which was also highly correlated with B. fragilis abundance. This result implied that B. fragilis could promote the secretion of prolactin by the pituitary gland. Together, the current study findings provided the information on gut microbiota influencing broody behavior, B. fragilis produced or driven more serum serotonin, and stimulated the pituitary gland to secret more prolactin, which potentially offered a new enlightenment for the intervention of broody behavior in poultry.

Chlortetracycline Concentration Impact on Salmonella Typhimurium Sustainability in the Presence of Porcine Gastrointestinal Tract Bacteria Maintained in Continuous Culture.

Concern exists that the continued use of antibiotics in animal feeds may lead to an increased prevalence of resistant bacteria within the host animal's gastrointestinal tract. To evaluate the effect of chlortetracycline on the persistence of Salmonella enterica serotype Typhimurium within a diverse population of porcine cecal bacteria, we cultured a mixed population of cecal bacteria without or with added chlortetracycline. When grown at a 24 h vessel turnover rate, chlortetracycline-susceptible S. Typhimurium exhibited more than 2.5 times faster (p < 0.05) disappearance rates than theoretically expected (0.301 log10 colony-forming unit/mL per day) but did not differ whether treated or not with 55 mg of chlortetracycline/L. Chlortetracycline-resistant S. Typhimurium was not recovered from any of these cultures. When the mixed cultures were inoculated with a chlortetracycline-resistant S. Typhimurium, rates of disappearance were nearly two times slower (p < 0.05) than those observed earlier with chlortetracycline-susceptible S. Typhimurium, and cultures persisted at >2 log10 colony-forming units/mL for up to 14 days of treatment with 110 mg of chlortetracycline/L. Under the conditions of this study, chlortetracycline-resistant S. Typhimurium was competitively enabled to persist longer within the mixed populations of porcine gut bacteria than chlortetracycline-susceptible S. Typhimurium, regardless of the presence or absence of added chlortetracycline.

Influence of Dietary Chitosan Supplementation on Growth Indicators, Nutrient Digestibility, Immunity, Cecal Microbiota, and Intestinal Morphology of Growing Male Rabbits

Abstract The present study aimed to assess the influence of dietary chitosan on production performance, nutrient digestibility, slaughter traits, immune function, cecal microbiota, and intestinal histomorphometry of growing rabbits for 56 days. In total, sixty New Zealand White male rabbits aged 35 days (574±7.26 g, mean ± SEM) were arbitrarily assigned to four dietary groups. The experimental diets were fortified with chitosan powder at 0, 250, 500, and 1000 mg per kg diet, respectively. It was found that final weight, specific growth rate, daily weight gain, and feed: gain enhanced linearly (P&lt;0.05) with increasing chitosan levels in the diet. No significant differences were found for all slaughter traits, including hot carcass weight, carcass yield, and internal organ weights, besides carcass parts, including head, fore, intermediate and hind parts. Hematocrit percentage (linear, P = 0.024), serum lysozyme activity (linear, P = 0.004), immunoglobulin M, and complement C3 concentrations (linearly, P&lt;0.001) increased with increasing chitosan supplementation levels. The organic matter (P = 0.009), dry matter (P = 0.008), and nitrogen-free extract (P = 0.012) digestibilities were enhanced quadratically by dietary supplementation with chitosan. Cecal lactobacilli, E. coli, coliform and Salmonella spp. populations (linear, P&lt;0.05) decreased in response to chitosan supplementation. All the dietary chitosan levels increased villus width, villus length, and crypt depth (linear, P&lt;0.001), whereas muscular layer thickness decreased (linear, P=0.002). In summary, supplementing the diet of growing rabbits with chitosan can improve growth indicators, immunity, nutrient digestibility, and intestinal morphology, as well as reduce pathogenic cecal bacteria.

Research Note: Effect of dietary xylo-oligosaccharide on growth performance, intestinal histomorphology, and specific cecal bacteria in broiler chickens

This study was conducted to evaluate the prebiotic effect of xylo-oligosaccharide (XOS) supplemented in a corn-soybean meal (SBM) based conventional diet on growth performance, intestinal histomorphology, and quantification of specific bacteria in the ceca of broilers. A total of 240 d of hatch Cobb 500 male broiler chicks were randomly assigned to 4 dietary treatments (corn-SBM-based control diet) containing 0, 0.05, 0.1, and 0.2% XOS. The broilers were raised for 21 d in 6 replicate cages, each containing 10 birds. Growth performance parameters were obtained weekly. Additionally, small intestinal tissues were collected to evaluate histomorphometry and whole ceca were collected to quantify bacterial populations on D21. The results showed that inclusion of XOS has similar body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) as the control group during the 21-day study. The results further indicate a tendency for the jejunum villus to crypt ratio (VH:CD) to increase in birds given 0.05 and 0.2% XOS (P=0.08). Cecal bacteria quantification showed a linear increase in Bifidobacterium with increasing XOS levels (P < 0.0001) and a decrease Clostridium perfringens levels compared to birds fed the control diet (P < 0.0001). However, there were no differences in the total counts of Lactobacillus and E. coli. Together these results showed that while there were no differences in growth parameters up to 21 d, the histomorphology findings and the increase in Bifidobacterium, along with the reduction in C. perfringens observed in the XOS groups, suggest a beneficial impact of XOS inclusion on gut health. Further research with longer feeding periods and higher XOS levels should be conducted to explore potential positive effects on both growth and gut health parameters.

Integrated Analysis of the Effects of Cecal Microbiota and Serum Metabolome on Market Weights of Chinese Native Chickens.

The gut microbiota plays an important role in the physiological activities of the host and affects the formation of important economic traits in livestock farming. The effects of cecal microbiota on chicken weights were investigated using the Guizhou yellow chicken as a model. Experimental cohorts from chickens with high- (HC, n = 16) and low-market-weights (LC, n = 16) were collected. Microbial 16S rRNA gene sequencing and non-targeted serum metabolome data were integrated to explore the effect and metabolic mechanism of cecal microbiota on market weight. The genera Lachnoclostridium, Alistipes, Negativibacillus, Sellimonas, and Ruminococcus torques were enriched in the HC group, while Phascolarctobacterium was enriched in the LC group (p < 0.05). Metabolomic analysis determined that pantothenic acid (vitamin B5), luvangetin (2H-1-benzopyran-6-acrylic acid), and menadione (vitamin K3) were significantly higher in HC serum, while beclomethasone dipropionate (a glucocorticoid) and chlorophene (2-benzyl-4-chlorophenol) were present at higher levels in the LC group. The microbes enriched in HC were significantly positively correlated with metabolites, including pantothenic acid and menadione, and negatively correlated with beclomethasone dipropionate and chlorophene. These results indicated that specific cecal bacteria in Guizhou yellow chickens alter the host metabolism and growth performance. This study provides a reference for revealing the mechanism of cecal microbe actions that affect chicken body weight.

Dietary supplementation with Dendrobium officinale leaves improves growth, antioxidant status, immune function, and gut health in broilers.

The Dendrobium officinale leaves (DOL) is an underutilized by-product with a large biomass, which have been shown to exhibit immunomodulatory and antioxidant functions. The purpose of this research was to investigate the effects of DOL on broiler growth performance, antioxidant status, immune function, and gut health. One hundred and ninety-two 1-day-old chicks were selected and divided into 4 groups at random, 6 replicates for each group and 8 in each. Chicks were given a basal diet supplemented with different amounts of DOL: 0% (control group, NC), 1% (LD), 5% (MD), or 10% (HD). During the feeding trial (70 days), broiler body weight, feed intake, and residual feeding were recorded. On d 70, 12 broilers from each group were sampled for serum antioxidant and immune indexes measurement, intestinal morphological analysis, as well as 16S rRNA sequencing of cecal contents and short-chain fatty acid (SCFA) determination. In comparison to the NC group, the LD group had greater final body weight and average daily gain, and a lower feed conversion ratio (p < 0.05, d 1 to 70). However, in MD group, no significant change of growth performance occurred (p > 0.05). Furthermore, DOL supplementation significantly improved the levels of serum total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase, but reduced the level of malondialdehyde (p < 0.05). Higher serum immunoglobulin A (IgA) content and lower cytokine interleukin-2 (IL-2) and IL-6 contents were observed in DOL-fed broilers than in control chickens (p <0.05). Compared to the NC group, duodenal villus height (VH) and villus height-to-crypt depth (VH:CD) ratio were considerably higher in three DOL supplementation groups (p < 0.05). Further, 16S rRNA sequencing analysis revealed that DOL increased the diversity and the relative abundance of cecal bacteria, particularly helpful microbes like Faecalibacterium, Lactobacillus, and Oscillospira, which improved the production of SCFA in cecal content. According to Spearman correlation analysis, the increased butyric acid and acetic acid concentrations were positively related to serum antioxidant enzyme activities (T-AOC and GSH-Px) and immunoglobulin M (IgM) level (p < 0.05). Overall, the current study demonstrated that supplementing the dies with DOL in appropriate doses could enhance growth performance, antioxidant capacity, and immune response, as well as gut health by promoting intestinal integrity and modulating the cecal microbiota in broilers. Our research may serve as a preliminary foundation for the future development and application of DOL as feed additive in broiler chicken diets.

Development of a Chicken Gastrointestinal Tract (GIT) Simulation Model: Impact of Cecal Inoculum Storage Preservation Conditions

A chicken gastrointestinal tract (GIT) simulation model was developed to help predict the potential effects of feed additives supplementation on chicken’ microbiota. The chemical and enzymatic conditions for oral, gastric, intestinal, and cecum fermentation phases were designed to closely resemble the chicken GIT conditions. For cecum fermentation, the inoculum was obtained from the cecal contents of 18 38-day broiler chickens. The impact of inoculum preservation on bacteria viability was assessed by comparing two methods of preservation with fresh inoculum: (1) 5% dimethyl sulfoxide (DMSO) at −80 °C and (2) 30% glycerol at −20 °C. The fermentation with fresh and frozen (DMSO method) inoculums was performed and compared using standard chicken feed (SCF) and SCF with 1% fructooligosaccharides (FOS), and inoculum control (IC) condition without feed matrix was used as a baseline. Inoculum’s viability was assessed throughout 90 days of storage by culture media platting, while bacterial growth and metabolites production during fermentation was evaluated by quantitative polymerase chain reaction (qPCR), high-performance liquid chromatography (HPLC), and total ammonia nitrogen quantification. The DMSO method was shown to be the most suitable for cecal inoculum storage. Higher growth of beneficial cecal bacteria for fresh inoculum was observed in SCF while for frozen inoculum, was the SCF + FOS condition. Also, frozen inoculum had lower activity of butyrate producers and proteolytic bacteria, showing different fermentation profiles. The GIT model developed showed to be useful to test the effect of feed additives supplementation.