Intestinal inflammation induced by dextran sodium sulphate causes liver inflammation and lipid metabolism disfunction in laying hens

Subclinical peripheral inflammation has systemic effects impacting central nervous system proteome in budgerigars

Regulation of neuroimmune interactions varies across avian species. Little is presently known about the interplay between periphery and central nervous system (CNS) in parrots, birds sensitive to neuroinflammation. Here we investigated the systemic and CNS responses to dextran sulphate sodium (DSS)- and lipopolysaccharide (LPS)-induced subclinical acute peripheral inflammation in budgerigar (Melopsittacus undulatus). Three experimental treatment groups differing in DSS and LPS stimulation were compared to controls. Individuals treated with DSS showed significant histological intestinal damage. Through quantitative proteomics we described changes in plasma (PL) and cerebrospinal fluid (CSF) composition. In total, we identified 180 proteins in PL and 978 proteins in CSF, with moderate co-structure between the proteomes. Between treatments we detected differences in immune, coagulation and metabolic pathways. Proteomic variation was associated with the levels of pro-inflammatory cytokine mRNA expression in intestine and brain. Our findings shed light on systemic impacts of peripheral low-grade inflammation in birds.

Lactobacillus reuteri alleviates LPS-induced intestinal mucosal damage by stimulating the expansion of intestinal stem cells via activation of the Wnt/β-catenin signaling pathway in broilers

The continuous expansion of intestinal stem cells (ISCs) is crucial for maintaining the renewal of the intestinal epithelium, particularly in inflammatory conditions. It remains largely unknown how the internal microbiota repair damage to the internal mucosal barrier. Hence, investigating potential anti-inflammatory probiotics from the intestinal symbolic microbes of broilers and analyzing their mechanism of action to support the intestinal mucosal barrier function can offer novel regulatory tools to alleviate broiler enteritis. In this research, we utilized in vivo broilers plus ex vivo organoids model to thoroughly examine the effectiveness of Lactobacillus reuteri (LR) in protecting the integrity of the intestinal mucosa during lipopolysaccharide-induced (LPS-induced) enteritis in broilers. The findings indicated that LR feeding maintained intestinal morphological and structural integrity, enhanced proliferation of intestinal epithelial cells, and inhibited cell apoptosis and inflammatory response against the deleterious effects triggered by LPS. Simultaneously, LR enhanced ISCs activity and stimulated intestinal epithelial regeneration to protect the intestinal barrier during LPS-induced injury conditions. The coculture system of LR and ileum organoids revealed that LR increased the growth of organoids and attenuated LPS-stimulated damage to organoids. Furthermore, the LPS-induced decrease in ISC activity was rescued by reactivation of Wnt/β-catenin signaling by LR ex vivo and in vivo. This research revealed that LR promoted the expansion of ISCs and intestinal epithelial cell renewal by regulating the Wnt/β-catenin signaling pathway, thereby maintaining the integrity of the intestinal mucosal barrier. This finding provided theoretical support for lactobacillus as a probiotic additive in livestock feed to improve intestinal inflammation and treat intestinal diseases.

Effects of oligosaccharides on performance, intestinal morphology, microbiota and immune reactions in laying hens challenged with dextran sodium sulfate

The aim of this study was to determine the effect of oligosaccharide extract from bamboo shoot (BOS) on the performance, intestinal morphology, microbiota and immune reaction of laying hens challenged with dextran sodium sulfate (DSS). Thirty-two White Leghorn hens (480 days old) were divided into 4 groups (8 hens each) with similar mean body weights: C (basal diet), D (basal diet + DSS), B (5 g/kg BOS diet), and BD (5 g/kg BOS diet + DSS). They were administered a single oral dose of 4 mL of distilled water/kg body weight with or without 0.45 g of DSS for 7 consecutive days from the 14th d to the 21st d of the experiment. The important findings were that (1) The egg yolk ratio was decreased by DSS treatment, but it was improved by BOS treatment, which also increased the egg shell ratio. (2) The diversity of intestinal microbiota and relative abundance of 4 bacteria genera were increased by BOS treatment. (3) Intestinal morphology was not affected by DSS and BOS, but the leukocytes accumulation in the liver was increased by DSS treatment and suppressed by BOS treatment. (4) Dietary BOS treatment influenced the mRNA expression of Th-1 and Treg cytokines in the liver and Th-17 cytokines in both intestine and liver of laying hens. These results suggest that BOS may enhance egg quality, Th-1 and Th-17 immune function without causing tissue damage under normal condition, and may suppress the excessive inflammatory responses during inflammation.

Quantitative lipidomics reveals the changes of lipids and antioxidant capacity in egg yolk from laying hens with fatty liver hemorrhagic syndrome

In laying hens, fatty liver hemorrhagic syndrome (FLHS) is a common metabolic disorder, which can affect egg production and nutritional value. However, the impact of FLHS on the lipid content in egg yolks was not clear. In this study, FLHS model was induced by using high-energy low-protein diet, and the egg quality was evaluated. Egg yolk lipids were quantitatively analyzed by using ultra-performance liquid chromatography-mass spectrometry combined with multivariate statistical analysis. Gene expressions of the lipoprotein were determined by qRT-PCR and antioxidant capacity of the egg yolk were determined by kits. The elevated blood lipids and extensive lipid droplets observed indicated successful establishment of the FLHS model in laying hens. Measurements of egg quality showed that egg yolk weight was increased in the FLHS group. Lipidomics revealed that 1,401 lipids, comprising 27 lipid subclasses in the egg yolk. According to score plots of principal component analysis and orthogonal partial least squares discriminant analysis, different lipid profile was observed between the control and FLHS groups. A total of 97 different lipid species were screen out. Sphingolipid and glycerophospholipid metabolism were identified as key pathways. Free polyunsaturated fatty acids (PUFA) exhibited an increase in the FLHS group (P < 0.05). Notably, the form of PUFAs was changed that the FLHS group showed an increase in triacylglycerol-docosahexenoic acid and triacylglycerol-arachidonic acid in the egg yolk, while triacylglycerol-α-linolenic acid was decreased (P < 0.05). Total superoxide dismutase was decreased in the egg yolks affected by FLHS. Gene expressions of vitellogenin 2 (VTG2), VTG3, very low-density apolipoprotein II and apolipoprotein B were increased in the liver of laying hens with FLHS (P < 0.05). In conclusion, FLHS promoted the lipid transport from the liver to the yolk by upregulating lipoprotein expression, which altered lipid profile, and reduced antioxidant capacity in the yolk. This study provided a foundation for understanding the changes in lipids, lipid transport and lipid antioxidation capacity in egg yolk from laying hens with FLHS.

Effects of gossypol acetate on growth, serum biochemical parameters, and intestinal health of goslings

Free gossypol (FG), the primary antinutritional component in cottonseed meal, can adversely affect the growth and health of poultry. Although younger geese are particularly sensitive to FG, the precise effects of FG on geese remain elusive. This study aimed to investigate the effects of gossypol acetate (GA), a form of FG, on the growth, serum biochemical parameters, and intestinal health of goslings. Seventy-two healthy male goslings, aged 7-day-old with similar body weight (BW), were randomly divided into 3 groups: a control group and 2 GA-treated groups (GA25 and GA50), which were orally administered GA (25 and 50 mg/kg BW) daily for 14 d. The results showed that oral administration of GA significantly suppressed BW, altered serum parameters, and impaired intestinal health in a dose- and time-dependent manner. Specifically, GA adversely affected intestinal morphology, induced oxidative stress, and inflammation, diminished immune function, and increased intestinal permeability and apoptosis of intestinal cells, consequently impairing nutrient absorption and utilization of goslings. Overall, these data indicate that GA adversely affects the growth, serum parameters, and intestinal health of goslings, providing valuable information further to understand the toxic effects of gossypol on goslings.

Effects of dietary supplementation of glycerol monolaurate on laying performance, egg quality, antioxidant capacity, intestinal morphology and immune function in late-phase laying hens

The objective of this study was to evaluate the effects of different levels of glycerol monolaurate (GML) on laying performance, egg quality, antioxidant capacity, intestinal morphology and immune function in late-phase laying hens. A total of 480 Hy-Line Variety Brown hens (age 54 wk) were randomly assigned to 5 treatments: the control group (basal diet) and 4 GML groups (basal diet supplemented with 100, 200, 300, and 400 mg/kg GML). Each treatment consisted of 8 replicates with 12 hens each and the trial lasted for 8 wk. The results showed that dietary inclusion of GML increased the ADFI in the entire experimental period and the average egg weight in wk 5 to 8 and wk 1 to 8 of the experiment (linear, P < 0.05). Dietary GML addition linearly increased albumen height, Haugh unit and yolk color, and quadratically increased eggshell thickness (P < 0.05). The serum SOD activity, T-AOC and IgG concentrations in the 200 mg/kg GML group, and GSH-Px activity in 200 and 300 mg/kg GML groups were increased, while the MDA concentration in 200 and 300 mg/kg GML groups was decreased than those in the control group (P < 0.05). The jejunal villus height and villus height: crypt depth in 300 mg/kg GML group were higher than that in the control group (P < 0.05). The mRNA expression of TLR4, IL-1β and TNF-α in spleen and jejunum decreased with the increase of dietary GML concentration (linear, P < 0.05). In conclusion, dietary GML supplementation could improve egg quality, antioxidant capacity, intestinal morphology and immune function in late-phase laying hens, and dietary 300 mg/kg GML inclusion is suggested.

Dietary Chinese herbal mixture supplementation improves production performance by regulating reproductive hormones, antioxidant capacity, immunity, and intestinal health of broiler breeders

Chinese herbs have been used as feed additives and are commonly utilized in domestic intensive livestock farming. However, their impact on the production performance and intestinal health of broiler breeders has yet to be thoroughly explored. This study aimed to evaluate the effects of a Chinese herbal mixture (CHM) on the production performance of broiler breeders in terms of reproductive hormones, antioxidant capacity, immunity, and intestinal health of broiler breeders. A total of 336 thirty-wk-old hens were randomly allotted to 4 groups with 6 replicates of fourteen hens each, which fed a basal diet supplemented with 0 (CON), 500 (CHM500), 1,000 (CHM1000), and 1,500 (CHM1500) mg/kg CHM for 56 days, respectively. Our results showed that dietary supplementation with CHM1000 increased the laying rate and number of SYF and decreased the feed conversion ratio (P < 0.05). All CHM groups increased oviduct and ovarian indexes, serum E2 and T-AOC levels, and decreased serum TG and MDA levels compared with CON (P < 0.05). In comparison to the CON group, the CHM1000 and CHM1500 groups increased serum ALB, IgM, and IL-10 levels, whereas the CHM1000 group also increased serum TP and SOD levels, and the CHM1500 group increased serum P and decreased serum TNF-α (P < 0.05). The addition of CHM increased FSHR expressions in the ovary, Claudin-1 expressions in the jejunum, and SOD1 expressions in the liver and ovary, but decreased the mRNA expressions of INH in the ovary as well as IL-2 and IL-6 expressions in the jejunum (P < 0.05). Moreover, CHM500 and CHM1000 groups increased CAT, GPx, and HO-1 expression in the ovary, and SOD1 and GPx expression in the jejunum, while decreasing IL-17A expression in the jejunum (P < 0.05). In addition, CHM1000 and CHM1500 groups increased villus height, VCR, and the mRNA expressions of Nrf2, HO-1, Occludin, and MUC2 in the jejunum, and IL-10 expression in the ovary, while decreasing IL-2 and IL-17A expression in the ovary, in addition to increasing GPx, Nrf2, HO-1, NQO1, and IL-10 expression in the liver (P < 0.05). Supplementation with CHM1000 increased ESR-α, ESR-β, GnRH, Nrf2, and NQO1 expression in the ovary, but decreased IFN-γ expression in the ovary as well as crypt depth in the jejunum (P < 0.05). Supplementing CHM1500 increased NQO1 and ZO-1 expression in the jejunum and decreased IL-2 in the liver (P < 0.05). The high-throughput sequencing results showed that dietary CHM1000 supplementation altered the composition of the intestinal microbiota, as evidenced by the regulation of the genera Lactobacillus, Faecalibacterium, and Phascolarctobacterium. PICRUSt analysis revealed that metabolic pathways of bacterial chemotaxis, butanoate metabolism, and synthesis and degradation of ketone bodies were enriched in the CHM1000 group. Spearman's correlation analysis indicated that the differentiated genera were significantly associated with the production performance, serum hormone, and gut barrier-related genes. Taken together, supplementation of CHM, especially at 1,000 mg/kg, could improve production performance by regulating reproductive hormones, antioxidant capacity, immunity, and intestinal health of broiler breeders, and maybe provide insights into its application as a potential feed additive to promote the performance of broiler breeders.

Graded levels of Eimeria infection modulated gut physiology and temporarily ceased the egg production of laying hens at peak production

An experiment was conducted to investigate the changes in gastrointestinal physiology, including intestinal leakage, immune response, oxidative stress, along with performance traits, of Hy-Line W-36 laying hens following Eimeria infection at peak egg production. A total of 360 laying hens, at 25 wk of age, were assigned randomly to 5 treatment groups, each consisting of 6 replicate cages, including a nonchallenged control group. The other 4 groups were inoculated with graded levels of mixed Eimeria species as high, medium-high, medium-low, and low doses, respectively. The body weight (BW) and body weight gain (BWG) of laying hens were measured from 0 to 14 days postinoculation (DPI). Average daily feed intake (ADFI) and hen-day egg production (HDEP) were measured from 0 to 15 and 0 to 28 DPI, respectively. Gut permeability was measured on 5 DPI, whereas oxidative stress, immune response, and expression of nutrient transporter genes were measured on 6 and 14 DPI. A significant linear reduction in BW and BWG was observed with increased Eimeria inoculation dosage on both 6 and 14 DPI (P < 0.001, P-Lin < 0.0001). An interaction between the Eimeria dosages and DPI was observed for ADFI (P < 0.0001). Feed intake in the challenged groups decreased starting at 4 DPI, with the most significant drop occurring at 7 DPI, which did not recover until 15 DPI. Following the challenge, gastrointestinal physiology shifted toward the host defense against the Eimeria infection by upregulating mRNA expression of tight junction proteins and immune responses while downregulating the expression of key nutrient transporters on 6 and 14 DPI (P < 0.05). An interaction between the Eimeria inoculation dosage and DPI was also observed for daily HDEP (P < 0.0001). Overall, HDEP was lower in the challenged groups compared to the control. Daily HDEP in the challenged groups dropped from 8 DPI and became similar to the control birds only after 24 DPI. Egg production temporarily ceased in most of the laying hens infected with the high and medium-high dosages of Eimeria. In conclusion, Eimeria infection activated the host immune response, negatively affecting the gastrointestinal health, growth performance, and temporarily ceased the egg production of Hy-Line W-36 laying hens when infected at peak production.

Yolk precursor synthesis and deposition in hierarchical follicles and effect on egg production performance of hens

Egg production of hens is related to ovarian follicles development. The hierarchical follicle development accompanies the deposition of a large amount of yolk precursor. The aim of this study was to illustrate the effects of strain and age on yolk deposition and egg production. The experiment compared yolk synthesis, transport, and deposition in 3 groups of hens: one of a high-yield commercial hybrid laying breed (Jinghong No.1) in 2 stages (35 wk and 75 wk; JH35, JH75) and one of Chinese native breed (Lueyang Black-Boned chicken) at 35 wk (LY35). The results showed that the number of hierarchical follicles in JH35 and JH75 was significantly more than in LY35. At the same time, the yolk weight of the LY35 and JH75 was significantly higher than that of JH35. The expression of apolipoprotein A1 and apolipoprotein B genes in the liver of JH35 was higher than that of JH75. The expression of the very low-density lipoprotein receptor gene in the JH75 ovary was higher than that of the other 2 groups. The plasma concentrations of very low-density lipoprotein and vitellogenin were no significant difference among groups. The yolk deposition in hierarchical follicles based on the fat-soluble dyes measurement meant that the rate of yolk deposition of LY35 was lower than the other 2 groups. In most cases, the yolk deposition of JH75 was higher than that of the other groups, but the process showed greater fluctuation over time. These results meant that the rate and stability of yolk deposition played an essential role in affecting egg performance. In summary, both strain and age were related to egg production, but the 2 factors might impact yolk deposition and egg-laying performance differently. The egg performance may be affected by both yolk precursor synthesis and deposition for different strains, but it may be affected by yolk precursor deposition for the old laying hens.

Dietary naringin supplementation on hepatic yolk precursors formation and antioxidant capacity of Three-Yellow breeder hens during the late laying period

In this study, the effects of naringin on hepatic yolk precursors formation and antioxidant capacity of Three-Yellow breeder hens during late laying period were evaluated. A total of 480 (54-wk-old) Three-Yellow breeder hens were randomly assigned to 4 groups (6 replicates of 20 hens): nonsupplemented control diet (C), and control diet supplemented with 0.1%, 0.2%, and 0.4% of naringin (N1, N2, and N3), respectively. Results showed that dietary supplemented with 0.1%, 0.2%, and 0.4% of naringin for 8 wk promoted the cell proliferation and attenuated the excessive fat accumulation in the liver. Compared with C group, increased concentrations of triglyceride (TG), total cholesterol (T-CHO), high-density lipoprotein cholesterol (HDL-C), and very low-density lipoprotein (VLDL), and decreased contents of low-density lipoprotein cholesterol (LDL-C) were detected in liver, serum and ovarian tissues (P < 0.05). After 8 wk of feeding with naringin (0.1%, 0.2%, and 0.4%), serum estrogen (E₂) level, expression levels of proteins and genes of estrogen receptors (ERs) increased significantly (P < 0.05). Meanwhile, naringin treatment regulated expression of genes related to yolk precursors formation (P < 0.05). Furthermore, dietary naringin addition increased the antioxidants, decreased the oxidation products, and up-regulated transcription levels of antioxidant genes in liver tissues (P < 0.05). These results indicated that dietary supplemented with naringin could improve hepatic yolk precursors formation and hepatic antioxidant capacity of Three-Yellow breeder hens during the late laying period. Doses of 0.2% and 0.4% are more effective than dose of 0.1%.

Sodium houttuyfonate derived from Houttuynia cordata Thunb improves intestinal malfunction via maintaining gut microflora stability in Candida albicans overgrowth aggravated ulcerative colitis

Candida albicans is a common opportunistic pathogen and normally resides in the human gut. Increasing number of reports link the overgrowth of C. albicans to the severity of ulcerative colitis (UC). Sodium houttuyfonate (SH), a derivative of the medicinal herb Houttuynia cordata Thunb, has been demonstrated to exhibit decent antifungal and anti-inflammatory activities. We showed previously that SH could ameliorate colitis mice infected with C. albicans. However, it is unclear whether the therapeutic effect of SH is connected to its modulation of intestinal microflora in UC. In this study, the impact of SH on the gut microbiota was explored in both cohabitation and non-cohabitation patterns. The results showed that in UC mice inflicted by C. albicans, the administration of SH could greatly improve the pathological signs, weaken the oxidative stress and inflammatory response, and enhance the intestinal mucosal integrity. By 16S rRNA gene sequencing, we found that C. albicans interference caused intestinal microbiota dysbiosis accompanied by an increase of some harmful pathogens including Klebsiella and Bacteroides. In contrast, SH could modulate the abundance and diversity of microbiota with an increase of several beneficial bacteria comprising short-chain fatty acid-producing bacteria (Lachnospiraceae_NK4A136_group, Intestinimonas) and probiotics (Lactobacillus and Alloprevotella). Furthermore, the cohabitation strategy could also prove the efficacy of SH, indicating a role of transmissible gut flora in the colitis model. These findings suggest that SH might be an effective compound for the treatment of UC complicated by C. albicans overgrowth through maintaining gut microbiota homeostasis, thereby improving intestinal function.

Quercetin alleviates intestinal inflammation and improves intestinal functions via modulating gut microbiota composition in LPS-challenged laying hens

Quercetin, a well-known flavonoid, has been demonstrated to exert beneficial effects on intestinal functions and gut microbiota in birds. In this study, we investigated the effects of quercetin supplementation on inflammatory responses, intestinal barrier functions and gut microbial community in LPS-challenged laying hens. A total of two hundred eighty-eight 32-wk-old Jingfen No.6 laying hens were randomly assigned to 3 groups, the CON group, the LC group and the LQ group. LQ group was fed with 0.4 mg/kg quercetin and at the end of 12 wk, LC and LQ groups were challenged intraperitoneally with lipopolysaccharide (LPS). After LPS challenge, 8 birds of each group were randomly selected and sampled. LPS challenge induced an obvious intestinal mucosal injury, necrosis and shedding, while quercetin intervention maintained its structure. Quercetin significantly decreased the elevated malondialdehyde contents (P < 0.05), and increased the activity of total antioxidant capacity and glutathione peroxidase (P < 0.05) in intestinal mucosa of LPS-challenged laying hens. Quercetin rescued the LPS-induced decreases in goblet cell density and mucin2 expression levels (P < 0.05). There was a significant decline (P < 0.05) in the mRNA expression of Claudin1 and Occludin in intestinal mucosa of LPS-challenged layers, which could be alleviated (P < 0.05) by dietary quercetin. LPS challenge induced the increased expression levels (P < 0.05) of IL-1β and TLR-4 in intestinal mucosa, while these rises could be reversed (P < 0.05) following dietary quercetin supplementation. LPS challenge induced a shift in gut microenvironment, and quercetin addition could elevate the relative abundance of some short chain fatty acids (SCFA)-producing or health-promoting bacteria such as Phascolarctobacterium, Negativicutes, Selenomonadales, Megamonas, Prevotellaceae, and Bacteroides_salanitronis. In conclusion, dietary quercetin addition ameliorated the LPS challenge-induced intestinal inflammation and improved intestinal functions, possibly associated with its modulation on gut microbiota, particularly the increased population of SCFA-producing bacteria.

Establishment of an Enteric Inflammation Model in Broiler Chickens by Oral Administration with Dextran Sulfate Sodium

This study aimed to evaluate the effectiveness of oral gavage of dextran sodium sulfate (DSS) to establish an enteric inflammation model in broilers. Forty 1-day-old male, yellow-feathered broilers were randomly divided into 2 groups with 5 replicates of 4 birds each for a 42-day trial. The experiment design used 2 groups: (1) the control group (CT), normal broilers fed a basal diet, and (2) the DSS group, DSS-treated broilers fed a basal diet. The DSS group received 1 mL of 2.5% DSS solution once a day by oral gavage from 21 to 29 days of age. The results showed that compared with those in CT, DSS treatment significantly increased histological scores for enteritis and mucosal damage at 29 and 42 days of age (p < 0.01) and the disease activity index (DAI) from 23 to 29 days of age (p < 0.01). DSS-treated broilers showed poor growth performance at 42 days of age, including decreased body weight and average daily gain and an increased feed conversion ratio (p < 0.01). DSS also caused gross lesions and histopathological damage in the jejunum of broilers, such as obvious hemorrhagic spots, loss of villus architecture, epithelial cell disruption, inflammatory cell infiltration, and decreased villus height. These results suggest that oral gavage of DSS is an effective method for inducing mild and non-necrotic enteric inflammation in broilers.

Polystyrene microplastics exacerbate experimental colitis in mice tightly associated with the occurrence of hepatic inflammation

The potential health effects of microplastics (MPs) have become a public concern due to their ubiquitousness in the environment and life. Numerous studies have demonstrated that a high dose of MPs can adversely affect gastrointestinal health. However, few studies have focused on the impact of microplastics on patients' health with respect to gastrointestinal diseases. Inflammatory bowel disease (IBD) has emerged as a global disease with a rapidly increasing incidence. IBD, a specific gastrointestinal illness characterized by acute, chronic inflammation and intestinal barrier dysfunction, might increase sensitivity to MPs exposure. Herein, we investigated the impact and mechanism of PS-MPs on dextran sodium sulfate (DSS)-induced colitis. The results demonstrated that gavage with PS-MPs alone caused minimal effects on the intestinal barrier and liver status of mice. For mice with colitis, additional PS-MPs exposure caused a shorter colon length, aggravated histopathological damage and inflammation, reduced mucus secretion, and increased the colon permeability. Furthermore, PS-MPs exposure also increased the risk of secondary liver injury associated with inflammatory cell infiltration. These findings provide more histopathological evidence and suggest a need for more research on the health risk of MPs for sensitive individuals.

An evaluation of the protective effects of chlorogenic acid on broiler chickens in a dextran sodium sulfate model: a preliminary investigation

This study was conducted to investigate the protective effects of chlorogenic acid (CGA) on broilers subjected to dextran sodium sulfate (DSS)-induced intestinal damage. One hundred and forty-four 1-day-old male Arbor Acres broiler chicks were allocated into one of 3 groups with 6 replicates of eight birds each for a 21-d trial. The treatments included: 1) Control group: normal birds fed a basal diet; 2) DSS group: DSS-treated birds fed a basal diet; and 3) CGA group: DSS-treated birds fed a CGA-supplemented control diet. An oral DSS administration via drinking water was performed from 15 to 21 d of age. Compared with the control group, DSS administration reduced 21-d body weight and weight gain from 15 to 21 d, but increased absolute weight of jejunum and absolute and relative weight of ileum (P < 0.05). DSS administration elevated circulating D-lactate concentration and diamine oxidase activity (P < 0.05), which were partially reversed when supplementing CGA (P < 0.05). The oral administration with DSS decreased villus height and villus height/crypt depth ratio, but increased crypt depth in jejunum and ileum (P < 0.05). Compared with the control group, DSS administration increased serum glutathione level and jejunal catalase activity and malonaldehyde accumulation, but decreased jejunal glutathione level (P < 0.05). In contrast, feeding a CGA-supplemented diet normalized serum glutathione and jejunal malonaldehyde levels, and increased jejunal glutathione concentration in DSS-administrated birds (P < 0.05). Additionally, CGA supplementation reduced ileal malonaldehyde accumulation in DSS-treated birds (P < 0.05). DSS challenge increased levels of serum interferon-γ and interleukin-6, jejunal interleukin-1β, tumor necrosis factor-α, and interleukin-6, and ileal interleukin-1β and interleukin-6 when compared with the control group (P < 0.05). The elevated serum interferon-γ and ileal interleukin-6 levels were normalized to control values when supplementing CGA (P < 0.05). The results suggested that CGA administration could partially prevent DSS-induced increased intestinal permeability, oxidative damage, and inflammation in broilers, although it did not improve their growth performance and intestinal morphology.

Chicken jejunal microbiota improves growth performance by mitigating intestinal inflammation

Background

Intestinal inflammation is prevalent in chicken, which results in decreased growth performance and considerable economic losses. Accumulated findings established the close relationship between gut microbiota and chicken growth performance. However, whether gut microbiota impacts chicken growth performance by lessening intestinal inflammation remains elusive.

Results

Seven-weeks-old male and female chickens with the highest or lowest body weights were significantly different in breast and leg muscle indices and average cross-sectional area of muscle cells. 16S rRNA gene sequencing indicated Gram-positive bacteria, such as Lactobacilli, were the predominant species in high body weight chickens. Conversely, Gram-negative bacteria, such as Comamonas, Acinetobacter, Brucella, Escherichia-Shigella, Thermus, Undibacterium, and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium were significantly abundant in low body weight chickens. Serum lipopolysaccharide (LPS) level was significantly higher in low body weight chickens (101.58 ± 5.78 ng/mL) compared with high body weight chickens (85.12 ± 4.79 ng/mL). The expression of TLR4, NF-κB, MyD88, and related inflammatory cytokines in the jejunum was significantly upregulated in low body weight chickens, which led to the damage of gut barrier integrity. Furthermore, transferring fecal microbiota from adult chickens with high body weight into 1-day-old chicks reshaped the jejunal microbiota, mitigated inflammatory response, and improved chicken growth performance.

Conclusions

Our findings suggested that jejunal microbiota could affect chicken growth performance by mitigating intestinal inflammation.

Gut microbiota-derived short chain fatty acids are potential mediators in gut inflammation

Gut inflammation is a challenging concern in humans and animals, which disturbs normal growth and leads to severe bowel diseases. Short chain fatty acids (SCFA) are the gut microbiota metabolites produced from fermentation of non-digestible carbohydrates, and have been reported to modulate gut inflammation. SCFA have been implicated as the potential therapeutic bioactive molecules for gut inflammatory diseases, and could be an alternative to antibiotic growth promoters (AGP). In this review, the existing knowledge about the types of SCFA, the related gut microbes producing SCFA, the roles of SCFA in maintaining gut homeostasis, and how SCFA modulate gut inflammation is summarized. The therapeutic application of SCFA in the treatment of inflammatory bowel disease (IBD) is also highlighted.

Relationship between Mucosal Barrier Function of the Oviduct and Intestine in the Productivity of Laying Hens

The mucosa of the intestine and oviduct of hens are susceptible to pathogens. Pathogenic infections in the mucosal tissues of laying hens lead to worsened health of the host animal, decreased egg production, and bacterial contamination of eggs. Therefore, better understanding of the mechanisms underlying mucosal barrier function is needed to prevent infection by pathogens. In addition, pathogen infection in the mucosal tissue generally causes mucosal inflammation. Recently, it has been shown that inflammation in the oviduct and intestinal tissue caused by disruption of the mucosal barrier function, can affect egg production. Therefore, it is vitla to understand the relationship between mucosal barrier function and egg production to improve poultry egg production. This paper reviews the studies on (1) oviductal mucosal immune function and egg production, (2) intestinal inflammation and egg production, and (3) improvement of mucosal immune function by probiotics. The findings introduced in this review will contribute to the understanding of the mucosal barrier function of the intestine and oviduct and improve poultry egg production in laying hens.

<i>Bacillus subtilis-</i>Fermented Products Ameliorate the Growth Performance, Alleviate Intestinal Inflammatory Gene Expression, and Modulate Cecal Microbiota Community in Broilers during the Starter Phase under Dextran Sulfate Sodium Challenge

The aim of this study was to evaluate the effects of B. subtilis-fermented products (BSFP) on growth performance, intestinal inflammatory gene expression, and cecal microbiota community in broilers challenged with dextran sulfate sodium (DSS) in a 14-day experiment. A total of 32, 1-day-old male broiler chickens (Ross 308), were randomly divided into four groups of eight birds per group and reared individually (n=8). The treatments consisted of a control diet without supplementation and DSS challenge, control diet plus 1.5% DSS, control diet plus 1 g/kg BSFP in combination with 1.5% DSS, and control diet plus 3 g/kg of BSFP in combination with 1.5% DSS. The results showed that BSFP supplementation (1 and 3 g/kg) partially improved body weight and average daily gain in broilers under DSS challenge. Relative to DSS treatment alone, BSFP supplementation dose-dependently increased the body weight of broilers at 7 days of age, with the average daily gain being at 1 to 7 days of age. BSFP supplementation (1 and 3 g/kg) alleviated intestinal inflammatory gene expression in broilers under DSS challenge. The richness and evenness of bacterial species in cecal digesta increased in a dose-dependent manner in the groups treated with BSFP (1 and 3 g/kg) in combination with DSS challenge, compared with the control group. Unweighted principal coordinate analysis indicated distinct clusters separating the group treated with 3 g/kg of BSFP in combination with DSS challenge from the other three groups. The abundance of short-chain fatty acid-producing bacteria (genus Ruminococcaceae_unclassified) increased and that of mucindegrading bacteria (genus Ruminococcus torques group) decreased in the cecal digesta of broilers fed 3 g/kg of BSFP, compared with the control group. In conclusion, BSFP supplementation dose-dependently improved growth performance, reduced gut inflammation, and regulated the cecal microbiota of broilers exposed to DSS challenge during the starter phase.

Mechanism of Ulcerative Colitis-Aggravated Liver Fibrosis: The Activation of Hepatic Stellate Cells and TLR4 Signaling Through Gut-Liver Axis

Background: The progression of liver disorders is frequently associated with inflammatory bowel disease through the gut-liver axis. However, no direct evidence showed the mechanisms of ulcerative colitis (UC) in the development of liver fibrosis per se. Thus, this study aimed to evaluate the effects of UC on liver fibrosis and its potential mechanism in the experimental model. Methods: Male C57BL/6 mice were allocated into five groups (n = 10 per group) to receive either drinking water (control), 2% dextran sulfate sodium (DSS), olive oil, carbon tetrachloride (CCl₄) or DSS + CCl₄ for 4 cycles. Blood was collected for biochemical analysis. Colons were excised for the evaluation of colon length and morphological score. Liver, colon, and mesenteric lymph nodes (MLNs) were collected for histopathological staining, expression analysis, and bacterial translocation assay to evaluate the inflammation, fibrosis, the activation of hepatic stellate cells (HSCs), and gut barrier function. Results: DSS caused severe colitis in mice treated or treated with CCl₄, as evident from the elevation of disease activity index (DAI), histological abnormalities, and increased pro-inflammatory cytokines (TNF-α, IFN-γ, and IL-17A). Histopathological staining revealed that DSS treatment aggravated the CCl₄-induced extracellular matrix deposition, liver fibrosis, and inflammation in mice. Additionally, biochemical and expression analysis indicated the DSS treatment caused the increase of hydroxyproline and pro-inflammatory cytokines, as well as the abnormal liver function indexes in CCl₄-induced mice. Gut barrier function was impaired in DSS- and DSS + CCl₄-treated mice, manifesting as the increase in bacterial translocation and lipopolysaccharide level, and the reduction in tight junction proteins (occluding, claudin-1 and ZO-1) expression. Further, the activations of HSCs and TLR4 signaling pathway were observed after DSS + CCl₄ treatment, presenting with the increase in expression of α-SMA, vimentin, TGF-β, collagen type I, collagen type II, TIMP-2, TLR4, TRAF6, and NF-κB p65, and a decrease in GFAP and MMP-2 expression. Conclusion: The present study verified that UC aggravated CCl₄-induced liver injury, inflammation, and fibrosis in mice through the gut-liver axis. Gut barrier dysfunction in UC leads to bacterial translocation and elevated lipopolysaccharide, which may promote the activation of TLR4 signaling and HSCs in the liver.

Dietary Valine Ameliorated Gut Health and Accelerated the Development of Nonalcoholic Fatty Liver Disease of Laying Hens

Valine is an important essential amino acid of laying hens. Dietary supplemented with BCAAs ameliorated gut microbiota, whereas elevated blood levels of BCAAs are positively associated with obesity, insulin resistance, and diabetes in both humans and rodents. General controlled nonrepressed (GCN2) kinase plays a crucial role in regulating intestinal inflammation and hepatic fatty acid homeostasis during amino acids deficiency, while GCN2 deficient results in enhanced intestinal inflammation and developed hepatic steatosis. However, how long-term dietary valine impacts gut health and the development of nonalcoholic fatty liver disease (NAFLD) remains unknown. Hence, in the present study, we elucidated the effects of dietary valine on intestinal barrier function, microbial homeostasis, and the development of NAFLD. A total of 960 healthy 33-weeks-old laying hens were randomly divided into five experimental groups and fed with valine at the following different levels in a feeding trial that lasted 8 weeks: 0.59, 0.64, 0.69, 0.74, and 0.79%, respectively. After 8 weeks of treatment, related tissues and cecal contents were obtained for further analysis. The results showed that diet supplemented with valine ameliorated gut health by improving intestinal villus morphology, enhancing intestinal barrier, decreasing cecum pathogenic bacteria abundances such as Fusobacteriota and Deferribacterota, and inhibiting inflammatory response mediated by GCN2. However, long-term intake of high levels of dietary valine (0.74 and 0.79%) accelerated the development of NAFLD of laying hens by promoting lipogenesis and inhibiting fatty acid oxidation mediated by GCN2-eIF2α-ATF4. Furthermore, NAFLD induced by high levels of dietary valine (0.74 and 0.79%) resulted in strengthening oxidative stress, ER stress, and inflammatory response. Our results revealed that high levels of valine are a key regulator of gut health and the adverse metabolic response to NAFLD and suggested reducing dietary valine as a new approach to preventing NAFLD of laying hens.

Effects of riboflavin deficiency on the lipid metabolism of duck breeders and duck embryos

This study aimed to evaluate the effects of dietary riboflavin deficiency (RD) on the lipid metabolism of duck breeders and duck embryos. A total of 40 female 40-wk-old white Pekin duck breeders were randomly divided into 2 groups, received either RD diet (1.48 mg riboflavin/kg) or control diet (16.48 mg riboflavin/kg, CON) for 14 wk. Each group consisted of 20 duck breeders (10 replicates per group, 2 birds per replicate), and all experiment birds were single-caged. At the end of the experiment, reproductive performance, hepatic riboflavin, hepatic flavin mononucleotide (FMN), hepatic flavin adenine dinucleotide (FAD), hepatic morphology, hepatic lipid contents, and hepatic protein expression of duck breeders and duck embryos were measured. The results showed that the RD had no effect on egg production and egg fertility but reduced egg hatchability, duck embryo weight, hepatic riboflavin, FMN, and FAD status compared to results obtained in the CON group (all P < 0.05). Livers from RD ducks presented enlarged lipid droplets, excessive accumulation of total lipids, triglycerides, and free fatty acids (all P < 0.05). In addition to excessive lipids accumulation, medium-chain specific acyl-CoA dehydrogenase expression was downregulated (P < 0.05), and short-chain specific acyl-CoA dehydrogenase expression was upregulated in maternal and embryonic livers (P < 0.05). RD did not affect maternal hepatic acyl-CoA dehydrogenase family member 9 (ACAD9) expression, but duck embryonic hepatic ACAD9 expression was reduced in the RD group (P < 0.05). Collectively, dietary RD conditioned lower egg hatchability and inhibited the development of duck embryos. Increased accumulation of lipids, both maternal and embryo, was impaired due to the reduced flavin protein expression, which caused inhibition of hepatic lipids utilization. These findings suggest that abnormal duck embryonic growth and low hatchability caused by RD might be associated with disorders of lipid metabolism in maternal as well as embryos.

Modulating the in vitro gastric digestion of heat-induced beta-lactoglobulin aggregates: Incorporation with polysaccharide

Three heat-induced protein aggregates, beta-lactoglobulin fibrils (BLGF), nanoparticles (BLGN), and worm-like aggregates (BLGW) were chosen to probe the effect of disulfide bond and surface hydrophobicity on their gastric digestion behavior. Furthermore, the effect of polysaccharide (dextran sulfate sodium, DSS) on the digestion behavior of the protein aggregates was investigated. Results showed that disulfide bond had a mild restraint on the digestion extent (maximum up to 4.65%), especially when its content was below 1 mol/mol, while the surface hydrophobicity had a stronger influence (up to 8.96%), and there is definitive positive linear relationship between the surface hydrophobicity and the digestion extent. When incorporated with DSS, both the disulfide bond content and surface hydrophobicity of the aggregates decreased, consequently, and the digestion was impeded, confirming the stronger effect from the surface hydrophobicity. The digestion extent of the heat-induced protein aggregates could be modulated linearly by incorporation of polysaccharide.

From Species to Regional and Local Specialization of Intestinal Macrophages

Initially intended for nutrient uptake, phagocytosis represents a central mechanism of debris removal and host defense against invading pathogens through the entire animal kingdom. In vertebrates and also many invertebrates, macrophages (MFs) and MF-like cells (e.g., coelomocytes and hemocytes) are professional phagocytic cells that seed tissues to maintain homeostasis through pathogen killing, efferocytosis and tissue shaping, repair, and remodeling. Some MF functions are common to all species and tissues, whereas others are specific to their homing tissue. Indeed, shaped by their microenvironment, MFs become adapted to perform particular functions, highlighting their great plasticity and giving rise to high population diversity. Interestingly, the gut displays several anatomic and functional compartments with large pools of strikingly diversified MF populations. This review focuses on recent advances on intestinal MFs in several species, which have allowed to infer their specificity and functions.

Slight Disruption in Intestinal Environment by Dextran Sodium Sulfate Reduces Egg Yolk Size Through Disfunction of Ovarian Follicle Growth

Intestinal environments such as microbiota, mucosal barrier function, and cytokine production affect egg production in laying hens. Dextran sodium sulfate (DSS) is an agent that disrupts the intestinal environment. Previously, we reported that the oral administration of dextran sodium sulfate (DSS: 0.9 g/kg BW) for 5 days caused severe intestinal inflammation in laying hens. However, the DSS concentration in the previous study was much higher to induce a milder disruption of the intestinal environment without heavy symptoms. Thus, the goal of this study was to determine the effects of a lower dose of DSS on the intestinal environment and egg production in laying hens. White Leghorn laying hens (330-day old) were oral administered with or without 0.225 g DSS/kg BW for 28 days (DSS and control group: n = 7 and 8, respectively). Weekly we collected all laid eggs and blood plasma samples. Intestinal tissues, liver, ovarian follicles, and the anterior pituitary gland were collected 1 day after the final treatment. Lower concentrations of orally administered DSS caused (1) a decrease in the ratio of villus height/crypt depth, occludin gene expressions in large intestine and cecal microbiota diversity, (2) a decrease in egg yolk weight, (3) an increase in VLDLy in blood plasma, (4), and enhanced the egg yolk precursor accumulation in the gene expression pattern in the follicular granulosa layer, (5) an increase in FSH and IL-1β gene expression in the pituitary gland, and (6) an increase in concentration of plasma lipopolysaccharide binding protein. These results suggested that the administration of the lower concentration of DSS caused a slight disruption in the intestinal environment. This disruption included poor intestinal morphology and decreased cecal microbiome diversity. The change in the intestinal environment decreases egg yolk size without decreasing the VLDLy supply from the liver. The decrease in egg yolk size is likely to be caused by the dysfunction of egg-yolk precursor uptake in ovarian follicles. In conclusion, the oral administration of a lower dose of DSS is an useful method to cause slight disruptions of intestinal environment, and the intestinal condition decreases egg yolk size through disfunction of ovarian follicle.