Dietary mannan oligosaccharide ameliorates cyclic heat stress-induced damages on intestinal oxidative status and barrier integrity of broilers

Chitosan oligosaccharide improves intestinal function by promoting intestinal development, alleviating intestinal inflammatory response, and enhancing antioxidant capacity in broilers aged d 1 to 14

This study was conducted to investigate the effects of chitosan oligosaccharide (COS) supplementation on intestinal development and functions, inflammatory response, antioxidant capacity and the related signaling pathways in broilers aged d 1 to 14. A total of 240 one-day old male Arbor Acres broilers (40.47 ± 0.30 g) were randomly allotted to 4 groups, and each group consisted of 6 replicate pens with 10 broilers per replicate. Broilers fed a basal diet supplementation with COS at 0 (CON group), 200 (COS200 group), 400 (COS400 group), and 800 mg/kg (COS800 group) for 14 d, respectively. Broilers in the COS supplementation groups had no significant effects on growth performance. Compared to the CON group, dietary COS supplementation increased (P < 0.05) the relative weight of duodenum, jejunal lipase activity, duodenal and ileal villus surface area, and lower (P < 0.05) ileal amylase and alkaline phosphatase activity, and crypt depth. The expression level of duodenal glucose transporter 1 (GLUT1), Na+-glucose cotransporter 1 (SGLT1), peptide transporter 1 (PepT1), occludin, zonula occludens-1 (ZO-1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and interleukin-10 (IL-10), jejunal SGLT1, PepT1, occludin, tumor necrosis factor-α (TNF-α), and ileal SGLT1, PepT1, and fatty acid binding protein 1 (FABP1) was upregulated by COS. However, the expression level of duodenal FABP1 and TNF-α, jejunal GLUT1, ZO-1, TLR4, MyD88, nuclear factor kappa-B p65 (NF-κB p65), and IL-1β, and ileal GLUT1, NF-κB p65, and IL-1β was downregulated by COS. Furthermore, dietary COS supplementation increased duodenal catalase (CAT), glutathione peroxidase (GSH-Px), and total superoxide dismutase (T-SOD) activity, jejunal CAT and T-SOD activity, upregulated the expression level of duodenal nuclear factor-erythroid 2-related factor 2 (Nrf2), CAT, glutathione peroxidase 1 (GPX1), and copper and zinc superoxide dismutase (Cu/Zn SOD), jejunal CAT, and ileal Nrf2, CAT, and GPX1. These results suggested that COS could promote intestinal development and functions in broilers aged d 1 to 14, which might be mediated by alleviating intestinal inflammatory response and enhancing antioxidant capacity.

Diets Supplemented with Probiotics Improve the Performance of Broilers Exposed to Heat Stress from 15 Days of Age

The poultry sector demands alternative additives to antibiotics that can be used as performance enhancers. Therefore, this experiment was conducted to evaluate the probiotics effects on performance, intestinal health, and redox status of 720 broilers exposed to heat stress from 15 days of age. Eight dietary treatments were evaluated: basal diet (BD) without antibiotic and probiotic (T1); BD supplemented with antibiotic zinc bacitracin (T2), BD supplemented with commercial probiotic of Bacillus subtilis DSM 17,299 (T3), BD supplemented with non-commercial probiotic of Lactococcus lactis NCDO 2118, Lactobacillus delbrueckii CNRZ 327, Escherichia coli CEC15, or Saccharomyces boulardii (T4 to T7), and BD simultaneously supplemented with the four non-commercial probiotics (T8). Feed intake, weight gain, and feed conversion were determined in the period from 1 to 42 days of age. Carcass and cuts yield, abdominal fat deposition, cloacal temperature, weight and length of intestine, activity of myeloperoxidase and eosinophilic peroxidase enzymes in the jejunum, jejunal histomorphometry, relative gene expression in the jejunum (occludin, zonulin, interleukin-8, cholecystokinin, ghrelin, and heat shock protein-70), and liver (heat shock protein-70), in addition to malondialdehyde level and superoxide dismutase activity in the intestine, liver, and blood, were measured in broilers at 42 days old. As main results, broilers fed T1 diet exhibited lower weight gain (3.222 kg) and worse feed conversion (1.70 kg/kg). However, diets containing non-commercial probiotics resulted in up to 3.584 kg of weight gain and improved feed conversion by up to 10%, similar to that observed for broilers of the T2 and T3 groups.

Mannan oligosaccharides selenium ameliorates intestinal mucosal barrier, and regulate intestinal microbiota to prevent Enterotoxigenic Escherichia coli -induced diarrhea in weaned piglets

Enterotoxigenic Escherichia coli (ETEC) is a common diarrheal pathogen in humans and animals. To prevent and treat ETEC induced diarrhea, we synthesized mannan oligosaccharide selenium (MOSS) and studied its beneficial effect on ETEC-induced diarrhea. A total of 32 healthy weaned piglets (6.69 ± 0.01 kg) were randomly divided into four groups: NC group (Basal diet), MOSS group (0.4 mg/kg MOSS supplemented diet), MOET group (0.4 mg/kg MOSS supplemented diet + ETEC treatment), ETEC group (ETEC treatment). NC and ETEC group fed with basal diet, MOSS and MOET group fed with the MOSS supplemented diet. On the 8th and 15th day of the experiment, MOET and ETEC group were gavaged with ETEC, and NC and MOSS group were gavaged with stroke-physiological saline solution. Our data showed that dietary MOSS supplementation increased average daily gain (ADG) and average daily feed intake (ADFI) and significantly decreased diarrhea index and frequency in ETEC-treated piglets. MOSS did not affect the α diversity and β diversity of ileal microbial community, but it significantly decreased the proportion of lipopolysaccharide biosynthesis in ileal microbial community. MOSS supplementation regulated colonic microbiota community composition, which significantly increased carbohydrate metabolism, and inhibited lipopolysaccharide biosynthesis pathway in colonic microbial community. Moreover, MOSS significantly decreased inflammatory stress, and oxidative stress in ETEC treated piglets. Furthermore, dietary MOSS supplementation significantly decreased intestinal barrier permeability, and alleviated ETEC induced intestinal mucosa barrier irritation. In conclusion, our study showed that dietary MOSS supplementation ameliorated intestinal mucosa barrier, and regulated intestinal microbiota to prevent ETEC induced diarrhea in weaned piglets.

Chitosan Oligosaccharides Alleviate Heat-Stress-Induced Lipid Metabolism Disorders by Suppressing the Oxidative Stress and Inflammatory Response in the Liver of Broilers

Heat stress has been reported to induce hepatic oxidative stress and alter lipid metabolism and fat deposition in broilers. Chitosan oligosaccharides (COSs), a natural oligosaccharide, has anti-oxidant, anti-inflammatory, and lipid-lowering effects. This study is conducted to evaluate dietary COS supplementation on hepatic anti-oxidant capacity, inflammatory response, and lipid metabolism in heat-stressed broilers. The results indicate that heat-stress-induced poor (p < 0.05) growth performance and higher (p < 0.05) abdominal adiposity are alleviated by COS supplementation. Heat stress increases (p < 0.05) serum AST and ATL activity, serum and liver MDA, TG, TC, and LDL-C levels, and the expression of hepatic IL-1β, IL-6, SREBP-1c, ACC, and FAS, while it decreases (p < 0.05) serum SOD and CAT activity, liver GSH-Px and SOD activity, and the expression of hepatic Nrf2, GPX1, IL-10, MTTP, PPARα, and CPT1. Nevertheless, COS supplementation decreases (p < 0.05) serum AST and ATL activity, serum and liver MDA, TG, TC, and LDL-C levels, and the expression of hepatic IL-1β, IL-6, SREBP-1c, ACC, and FAS, while it increases (p < 0.05) serum SOD and CAT activity, liver GSH-Px activity, and the expression of hepatic Nrf2, CAT, IL-10, LPL, MTTP, PPARα, and CPT1. In conclusion, COS could alleviate heat-stress-induced lipid metabolism disorders by enhancing hepatic anti-oxidant and anti-inflammatory capacity.

Role of dietary tea polyphenols on growth performance and gut health benefits in juvenile hybrid sturgeon (Acipenser baerii ♀ × A. schrenckii ♂)

The present study aimed to evaluate the effects of dietary TPs on growth performance, intestinal digestion, microflora and immunity in juvenile hybrid sturgeon. A total of 450 fish (97.20 ± 0.18 g) were randomly divided into a standard diet (TP-0) or four treatments consisting of a standard diet supplemented with four concentrations of TPs (mg/kg): 100 (TP-100), 300 (TP-300), 500 (TP-500), and 1000 (TP-1000) for 56 days. The TP-300 significantly increased weight gain rate (WGR) and specific growth rate (SGR) (p < 0.05), and TP-1000 significantly increased the feed conversion ratio (FCR) (p < 0.05). TP-300 and TP-500 significantly increased intestinal trypsin, amylase, and lipase activities (p < 0.05). Besides, TP-300 significantly enhanced total antioxidant capacity (T-AOC) and the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) and decreased malondialdehyde (MDA) content (p < 0.05). Moreover, TP-300 decreased the expression levels of tumor necrosis factor-alpha (TNF-α), interleukin 8 (IL-8), and interleukin 1β(IL-1β) compared with TP-0 and TP-1000 (p < 0.05). In addition, the intestinal microbiota diversity in the TP-300 group was observably higher, the dominant microbiota was Bacteroidota, Cyanobacteria, Proteobacteria and Firmicutes at the phylum level, Enterobacteriaceae, Nostocaceae and Clostridiaceae at the family level. The relative abundances of potential probiotics including Rhodobacteraceae and potential pathogens especially Clostridiaceae were the highest, and lowest, respectively. In conclusion, TP-300 altered the abundance of microbial taxa, resulting in enhancing the intestinal digestion, antioxidant status and non-specific immunity to improve the growth performance in juvenile hybrid sturgeon.

Intermittent and Mild Cold Stimulation Maintains Immune Function Stability through Increasing the Levels of Intestinal Barrier Genes of Broilers

In order to improve the adaptability of broilers to low-temperature environments and their ability to resist acute cold stress (ACS), 240 one-day-old broilers were selected and randomly divided into three groups. The control treatment (CC) group was raised at the conventional feeding temperature from 1-43 days (d), the cold stimulation treatment (CS) group was kept at 3 °C below the temperature of CC at 1 d intervals for 3 and 6 h from 15 to 35 d, namely, CS3 and CS6, respectively. Then, all broilers were kept at 20 °C from 36 to 43 d. ACS was then carried out at 44 d, and the ambient temperature was dropped to 10 °C for 6 h. The study investigated the production performance, as well as levels of intestinal barrier genes (including Claudin-1, E-cadherin, Occludin, ZO-1, ZO-2 and Mucin2), secretory IgA in duodenum and jejunum, and immunoglobulins (IgA and IgG) in serum. The results showed that IMCS could increase the daily weight gain and decrease the feed conversion ratio. During IMCS, the expression levels of intestinal barrier genes were up-regulated and the content of secretory IgA was increased. When IMCS ceased for one week, the level of immunoglobulins in serum stabilized, and the expression levels of Occludin, ZO-2 and Mucin2 still maintained high levels. After ACS, broilers that received IMCS training maintained high levels of intestinal barrier genes and secretory IgA.

Dietary yeast glycoprotein supplementation improves the growth performance, intestinal health and disease resistance of largemouth bass (Micropterus salmoides) fed low-fishmeal diets

The active ingredients extracted from yeast are important for regulating animal health. The aim of the current research was to explore the impacts of dietary yeast glycoprotein (YG) on the growth performance, intestinal morphology, antioxidant capacity, immunity and disease resistance of largemouth bass (Micropterus salmoides). A total of 375 juvenile fish (6.00 ± 0.03 g) were allocated into 15 fiberglass tanks. Triplicate tanks were assigned to each diet. The dietary YG inclusion was as follows: the first group was given a high fishmeal diet (40% fishmeal, 0% YG) (FM) and the second group was given a low fishmeal diet (30% fishmeal and 15% soybean meal, 0% YG) (LFM). The fish in the third, fourth and fifth groups were fed the LFM diet supplemented with 0.5% (LFM+YG0.5), 1.0% (LFM+YG1.0) and 2.0% (LFM+YG2.0) YG, respectively. After a 60- day feeding trial, a challenge test using A. hydrophila was carried out. The results showed that the final body weight (FBW) and weight gain rate (WGR) in the LFM+YG2.0 group were significantly higher than those in the LFM group and were no significantly different from those in the FM group. This may be partially related to the activation of the target of rapamycin (TOR) signaling pathway. Dietary YG supplementation enhanced intestinal physical barriers by upregulating the intestinal tight junction protein related genes (claudin1, occludin and zo2) and improving the structural integrity of the gut, which may be partially associated with AMPK signaling pathway. Moreover, dietary YG increased the antioxidant capacity in the gut, upregulated intestinal anti-inflammatory factors (il-10, il1-1β and tgf-β) and downregulated proinflammatory factors (il-1β and il-8), which may be partially related to the Nrf2/Keap1 signaling pathways. The results of the challenge test indicated that dietary supplementation with 0.5 or 1.0% YG can increase the disease tolerance of largemouth bass against A. hydrophila. In conclusion, the present results indicated that dietary supplementation with YG promotes the growth performance, intestinal immunity, physical barriers and antioxidant capacity of largemouth bass. In addition, 1.0% of dietary YG is recommended for largemouth bass based on the present results.

Chicken embryo thermal manipulation alleviates postnatal heat stress-induced jejunal inflammation by inhibiting Transient Receptor Potential V4

Intestinal inflammation induced by heat stress is an important factor restricting the healthy growth of broilers. The aim of this study was to evaluate the effect of chicken embryo thermal manipulation (39.5 ℃ and 65 % RH for 3 h daily during 16-18 th embryonic age) on intestinal inflammation in broilers under postnatal heat stress and to investigate whether transient receptor potential V4 (TRPV4) plays a role in this process. Our results suggest that broilers with embryo thermal manipulation experience could delay the rising of rectal temperature during postnatal heat stress (P < 0.05), and had better production performance (P < 0.05), intestinal morphological parameters (P < 0.05) and higher expression of tight junction related genes (P < 0.05). The increased serum lipopolysaccharide (LPS) content, activation of nuclear factor-kappa B (NF-κB) signaling pathway and the increased expression of pro-inflammatory cytokines interleukin (IL)-1β, IL-6 and tumor necrosis factor alpha (TNF-α) in jejunum during postnatal heat stress were alleviated by embryo thermal manipulation (P < 0.05). Postnatal heat stress induced an increase in mRNA and protein expression of TRPV4 in jejunum (P < 0.05), but had no effect on broilers which experienced embryo thermal manipulation (P > 0.05). Inhibition of TRPV4 reduced LPS-induced Ca²⁺ influx and restrained the activation of NF-κB signaling pathway and the expression of downstream pro-inflammatory cytokines (P < 0.05). The expression of DNA methyltransferase (DNMT) in the jejunum of broilers exposed to postnatal heat stress was increased by embryo thermal manipulation (P < 0.05). The DNA methylation level of TRPV4 promoter region was detected, and the results showed that embryo thermal manipulation increased the DNA methylation level of TRPV4 promoter region (P < 0.05). In conclusion, Chicken embryo thermal manipulation can alleviate jejunal inflammation in broilers under postnatal heat stress. This may be due to the decreased circulating LPS or the increased DNA methylation level in the promoter region of TRPV4, which inhibits TRPV4 expression, thereby reducing Ca²⁺ influx, and finally alleviating inflammation by affecting NF-κB signaling pathway. The work is an attempt to understand the mechanism involved in alleviation of adverse effects of heat stress during postnatal life through prenatal thermal manipulation and to reveal the important role of epigenetics.

Transcriptome wide analyses reveal intraspecific diversity in thermal stress responses of a dominant habitat-forming species

The impact of climate change on biodiversity has stimulated the need to understand environmental stress responses, particularly for ecosystem engineers whose responses to climate affect large numbers of associated organisms. Distinct species differ substantially in their resilience to thermal stress but there are also within-species variations in thermal tolerance for which the molecular mechanisms underpinning such variation remain largely unclear. Intertidal mussels are well-known for their role as ecosystem engineers. First, we exposed two genetic lineages of the intertidal mussel Perna perna to heat stress treatments in air and water. Next, we ran a high throughput RNA sequencing experiment to identify differences in gene expression between the thermally resilient eastern lineage and the thermally sensitive western lineage. We highlight different thermal tolerances that concord with their distributional ranges. Critically, we also identified lineage-specific patterns of gene expression under heat stress and revealed intraspecific differences in the underlying transcriptional pathways in response to warmer temperatures that are potentially linked to the within-species differences in thermal tolerance. Beyond the species, we show how unravelling within-species variability in mechanistic responses to heat stress promotes a better understanding of global evolutionary trajectories of the species as a whole in response to changing climate.

Effect of dietary Saccharomyces-derived prebiotic refined functional carbohydrates as antibiotic alternative on growth performance and intestinal health of broiler chickens reared in a commercial farm

The search for effective in-feed antibiotic alternative is growing due to the global trend to reduce or ban the utilization of antibiotics as growth promotors in poultry diets. This study was processed to assess the effect of dietary refined functional carbohydrates (RFCs) replacing antibiotic growth promoters (AGP) on growth performance, intestinal morphologic structure and microbiota, as well as intestinal immune function and barrier function of broilers reared on a commercial broilers farm. Trials contained 3 treatments with 4 replicate broiler houses, with about 25,000 birds each room. The treatments were control group (CON), RFCs group (CON + 100 mg/kg RFCs), and AGP group (CON + 50 mg/kg bacitracin methylene disalicylate (BMD), respectively. Results showed that RFCs and AGP group significantly increased (P < 0.05) average daily gain (ADG) during d 22 to 45 in contrast to control. Compared with the control and AGP-treated groups, feeding RFCs increased (P < 0.05) jejunal villus height to crypt depth ratio. AGP addition reduced (P < 0.05) the jejunal villi surface area compared to broilers fed control and RFC supplemented diets. Supplementation of RFCs promoted (P < 0.05) the growth of Lactobacillus but inhibited Escherichia coli and Salmonella proliferation compared with the control group. Inclusion of RFCs and BMD enhanced (P < 0.05) antibody titers against avian influenza virus H9 compared with control. RFCs and AGP both down-regulated (P < 0.05) intestinal TLR4 mRNA levels, whereas RFCs tended to up-regulate (P = 0.05) IFN-γ gene expression compared to control. Expression of intestinal tight junction genes was not affected by either AGP or RFCs supplementation. Based on above observation, we suggested that RFCs could replace in-feed antibiotic BMD in broiler diets for reducing intestinal pathogenic bacteria and modulating immunity of broilers.

Dietary supplementation modified attapulgite promote intestinal epithelial barrier and regulate intestinal microbiota composition to prevent diarrhea in weaned piglets

Attapulgite is a kind of natural clay mineral. Its unique pore structure makes it an ideal adsorption material and carrier material. However, the beneficial effect of modified attapulgites (SLK) in livestock is still unknown. The study was aimed to investigate the beneficial effect of modified attapulgites on diarrhea. 135 piglets were randomly divided into 5 groups and fed with control diet, traditional antibiotic substitute (TAS) supplementation diet, 0.5 mg/kg SLK supplementation diet, 1 mg/kg SLK supplementation diet, and 1.5 mg/kg SLK supplementation diet. This experiment lased two weeks. According to our result, 1.5 mg/kg SLK supplementation diet significantly decreased diarrhea score and diarrhea frequency, and effectively increased survival rate (P < 0.05). Dietary supplementation with 1.5 mg/kg SLK significantly increased high density lipoprotein cholesterol (HDLC), and choline esterase (CHE) concentration in serum (P < 0.05). AS compared with TAS group, 1.5 mg/kg SLK supplementation diet significantly decreased villus height and increased goblet number in jejunum, and increased villus height and decreased goblet number in ileum (P < 0.05). 1.5 mg/kg SLK supplementation diet also significantly changed cecal microbial community composition, including increased Limosilactobacillus abundance (P < 0.05). 1.5 mg/kg SLK supplementation diet significantly increased colonic microbial community composition, including decreased Escherichia-shigella abundance and increased Limosilactobacillus abundance (P < 0.05). Moreover, 1.5 mg/kg SLK supplementation diet significantly increased valerate, propionate, butyrate, and total short chain fatty acid contents in colon (P < 0.05). Valerate, propionate, butyrate, and total short chain fatty acid significantly associated with Lactobacillus. Fourerenilla and Fourerenilla.unclassfied significantly associated with acetate contents in colon (P < 0.05). In conclusion, dietary supplementation with modified apptapulgites significantly regulate intestinal microbial community composition and alleviate intestinal epithelial barrier to prevent diarrhea in piglets.

Dietary supplementation with synbiotics improves growth performance, antioxidant status, immune function, and intestinal barrier function in broilers subjected to cyclic heat stress

This study investigated the effects of synbiotics supplementation on growth performance, antioxidant status, immune function, and intestinal barrier function in broilers subjected to cyclic heat stress. One hundred and forty-four 22-day-old male broilers were randomly assigned to one of three treatment groups of six replicates each for a 21-day study, with eight birds per replicate. Broilers in the control group were reared at a thermoneutral temperature and received a basal diet. Broilers in the other two heat-stressed groups were fed a basal diet supplemented without (heat-stressed group) and with 1.5 g/kg synbiotic (synbiotic group). One and a half gram of the synbiotic consisted with 3 × 10⁹ colony forming units (CFU) Clostridium butyricum, 1.5 × 10⁹ CFU Bacillus licheniformis, 4.5 × 10¹⁰ CFU Bacillus subtilis, 600 mg yeast cell wall, and 150 mg xylooligosaccharide. Compared with the control group, heat stress increased rectal temperatures at 28, 35, and 42 days of age, respectively (P < 0.05). Birds subjected to heat stress had reduced weight gain, feed intake, and feed efficiency during 22 to 42 days (P < 0.05). In contrast, supplementation with the synbiotic decreased rectal temperature at 42 days of age and elevated weight gain of heat stress-challenged broilers (P < 0.05). Heat-stressed broilers exhibited a lower superoxide dismutase (SOD) activity in jejunal mucosa and a higher malondialdehyde accumulation in serum, liver and jejunal mucosa (P < 0.05), and the regressive SOD activity was normalized to control level when supplementing synbiotic (P < 0.05). Heat stress increased interleukin-1β (IL-1β) and interferon-γ (IFN-γ) levels in serum and IL-1β content in jejunal mucosa of broilers (P < 0.05). Synbiotic reduced IL-1β level in serum of broilers subjected to heat stress (P < 0.05). Compared with the control group, elevated serum diamine oxidase activity and reduced jejunal villus height were observed in broilers of the heat-stressed group (P < 0.05), and the values of these two parameters in the synbiotic group were intermediate (P > 0.05). Heat stress upregulated mRNA abundance of IL-1β and IFN-γ and downregulated gene expression levels of occluding and zonula occluden-1 (ZO-1) in jejunal mucosa of broilers (P < 0.05). The alterations in the mRNA expression levels of jejunal IL-1β and ZO-1 were reversed by the synbiotic (P > 0.05). In conclusion, dietary synbiotics could improve growth performance, antioxidant capacity, immune function, and intestinal barrier function in heat-stressed broilers.

Effects of in ovo feeding of chlorogenic acid on antioxidant capacity of postnatal broilers

In this study, chlorogenic acid (CGA) was injected into the amniotic cavity of chicken embryos to study the effects of in ovo feeding of CGA on the antioxidant capacity of postnatal broilers. On the 17th day of embryonic age, a total of 300 healthy broiler fertile eggs with similar weights were randomly subjected to five groups as follows; in ovo injection with 0.5 ml CGA at 4 mg/egg (4CGA) or 7 mg/egg (7CGA) or 10 mg/egg (10CGA), or sham-injection with saline (positive control, PC) or no injection (negative control, NC). Each group had six replicates of ten embryos. Six healthy chicks with similar body weights hatched from each replicate were selected and reared until heat stress treatment (35°C ± 1°C, 8 h/d) at 28-42 days of age. The results showed that there was no significant difference in the hatching rate between the groups (p > 0.05). After heat stress treatment, 4CGA group showed an improved intestinal morphology which was demonstrated by a higher villus height in the duodenum and a higher villus height/crypt depth ratio in the jejunum, compared with the NC group (p < 0.05). The antioxidant capacity of chickens was improved by in ovo feeding of CGA since 4CGA decreased the plasma content of malondialdehyde (MDA) (p < 0.05), whereas, it increased the superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities compared with NC group (p < 0.05). Also, the MDA content of the different injection groups had a quadratic effect, with the 4CGA group having the lowest MDA content (P _quadratic < 0.05). In the duodenum, 4CGA injection significantly increased the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (H O -1), glutathione synthetase (GSS), and SOD1 compared to the NC and PC groups (p < 0.05). The mRNA expressions of glutathione reductase (GSR) and GPX7 were significantly increased in all CGA-treated groups compared with the PC group (p < 0.05), while the mRNA expression of CAT was significantly increased by 4CGA group than the NC group (p < 0.05). The mRNA expressions of epigenetic-related genes, ten eleven translocation 1 and 2 (Tet1 and Tet2), and DNA-methyltransferase 3 alpha (DNMT3A) in the duodenum of 4CGA injected group was significantly increased compared with the NC and PC groups (p < 0.05). The mRNA expressions of Nrf2, SOD1, and Tet2 showed a significant quadratic effects with the 4CGA group having the highest expression (P _quadratic < 0.05). In conclusion, in ovo feeding of CGA alleviated heat stress-induced intestinal oxidative damage. Injection with CGA of 4 mg/egg is considered most effective due to its actions in improving intestinal antioxidant capacity, especially in the duodenum. The antioxidant effects of in ovo CGA on postnatal heat-stressed broilers may be related to its regulation of epigenetic mechanisms. Thus, this study provides technical knowledge to support the in ovo feeding of CGA to alleviate oxidative stress in postnatal heat-stressed broilers.

Guanidinoacetic acid supplementation improves intestinal morphology, mucosal barrier function of broilers subjected to chronic heat stress

The current study is designed to investigate dietary guanidinoacetic acid (GAA) supplementation on the growth performance, intestinal histomorphology, and jejunum mucosal barrier function of broilers that are subjected to chronic heat stress (HS). A total of 192 male broilers (28-d old) were randomly allocated to four groups. A chronic HS model (at a temperature of 32 °C and 50%-60% relative humidity for 24 h daily) was applied in the experiment. Normal control (NC, ad libitum feeding, 22 °C), HS group (HS, ad libitum feeding, 32 °C), pair-fed group (PF, received food equivalent to that consumed by the HS group on the previous day, 22 °C), guanidinoacetic acid group (HG, ad libitum feeding, supplementing the basal diet with 0.6 g/kg GAA, 32 °C). The experiment lasted from 28 to 35 and 28 to 42 d of age of broilers. Our results showed that broilers subjected to HS had lower average daily feed intake and average daily gain (P < 0.05), higher feed-to-gain ratio and relative length of the small intestine (P < 0.05), as well as lower relative weight and weight per unit length of the small intestine (P < 0.05). HS damaged the small intestinal histomorphology by decreasing the small intestinal VH and the VH/CD (P < 0.05). Compared with the HS group, supplementation with 0.6 g/kg GAA increased jejunal VH and VH/CD (P < 0.05), but decreased relative weight and relative length of the small intestine (P < 0.05). Moreover, in comparison with NC, HS elevated intestinal permeability (D-Lactic acid concentration and diamine oxidase activity) and mRNA expression levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α (P < 0.05), reduced jejunal mucus thickness, number of goblet cells, IgA + cell density, and mucin2 mRNA expression level of broilers (P < 0.05). Compared with the HS group, dietary GAA elevated jejunal mucus thickness, goblet cell number and IgA+ cell density (P < 0.05), and up-regulated jejunal mRNA expression of interleukin-1β and tumor necrosis factor-α (P < 0.05). In conclusion, HS impaired growth performance, and the intestinal mucosal barrier function of broilers. Dietary supplementation with 0.6 g/kg GAA alleviated HS-induced histomorphology changes of small intestine and jejunal mucosal barrier dysfunction.

Compound bioengineering protein improves growth performance and intestinal health in broiler chickens under high-temperature conditions

In recent years, more frequent and prolonged periods of high ambient temperature in summer compromised poultry production worldwide. This study was conducted to investigate the effects of compound bioengineering protein (CBP) on the growth performance and intestinal health of broilers under high ambient temperatures. A total of 400 one-day-old Arbor Acres birds were randomly distributed into five treatment groups: control group (CON) with basal diet, or a basal diet supplemented with CBP 250, 500, 750, and 1,000 mg/kg, respectively. The trial lasted 42 d, all birds were raised at normal ambient temperature for the first 21 d and then subjected to the artificial hyperthermal condition with the temperature at 32 ± 2 °C and relative humidity at 60 ± 5% during 22 to 42 d. Dietary CBP supplementation improved the growth performance and serum antioxidant capacity (total antioxidant capacity and total superoxide dismutase), and decreased serum cortisol, aminotransferase, and alkaline phosphatase of broilers. Dietary CBP inclusion enhanced intestinal barrier function by promoting intestinal morphology and reducing intestinal permeability (diamine oxidase), increased the intestinal antioxidant capacity by elevating glutathione peroxidase activity in the duodenum, reducing malondialdehyde content in the jejunum. Dietary CBP supplementation also alleviated intestinal inflammation by decreasing interleukin (IL)-6 content in the jejunum and ileum, promoting IL-10 levels in the ileum, down-regulating the mRNA abundance of intestinal inflammatory-related genes interferon-gamma (IFN-γ) in the duodenum and up-regulating IL-10 in the jejunum. Additionally, CBP increased the population of total bacteria and Lactobacillus in cecal chyme. Collectively, dietary CBP inclusion exerts beneficial effects on the broilers, which are reflected by enhancing antioxidant capacity, promoting intestinal barrier function, ameliorating intestinal immune response, and regulating intestinal bacteria, thus improving the growth performance of broilers under high-temperature conditions. In general, 750 mg/kg CBP supplementation is more effective.

Integrated transcriptome analysis for the hepatic and jejunal mucosa tissues of broiler chickens raised under heat stress conditions

Background

Heat stress (HS) is one of the most important threats for the current poultry industry. Therefore, many efforts have been made to ameliorate the adverse effect of HS on poultry production; however, physiological and molecular mechanisms pertaining to HS are still limited in poultry. Therefore, the objective of the current study was to investigate functional alterations based on individual and integrated transcriptomes in the liver and jejunal mucosa tissues of broiler chickens exposed to HS conditions.

Results

Broiler chickens exposed to HS showed decreased growth performance and increased corticosterone concentrations in the feather. In the transcriptome analysis, the number of differentially expressed genes (DEGs) were identified in the liver and jejunal mucosa by HS conditions. In the liver, genes related to amino acid oxidation, tryptophan metabolism, lipid metabolism, oxidative phosphorylation, and immune responses were altered by HS, which support the reason why heat-stressed poultry had decreased productive performance. In the jejunal mucosa, genes related to defense systems, glutathione metabolism, detoxification of xenobiotics, and immune responses were differently expressed by HS conditions. The integrated transcriptome analysis with DEGs found in the liver and jejunal mucosa showed a considerable connectivity between the core nodes in the constructed networks, which includes glutathione metabolism, xenobiotic metabolism, carbon metabolism, and several amino acid metabolisms.

Conclusions

The core network analysis may indicate that increased requirement of energy and amino acids in the jejunal mucosa of broiler chickens exposed to HS conditions is likely compromised by increased oxidation and synthesis of amino acids in the liver. Therefore, our results may provide comprehensive insights for molecular and metabolic alterations of broiler chickens raised under HS conditions, which can aid in the development of the novel strategies to ameliorate the negative effect of HS on poultry productivity and health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00734-y.

New insights into immunomodulatory properties of lactic acid bacteria fermented herbal medicines

The COVID-19 pandemic has brought more attention to the immune system, the body’s defense against infectious diseases. The immunomodulatory ability of traditional herbal medicine has been confirmed through clinical trial research, and has obvious advantages over prescription drugs due to its high number of potential targets and low toxicity. The active compounds of herbal drugs primarily include polysaccharides, saponins, flavonoids, and phenolics and can be modified to produce new active compounds after lactic acid bacteria (LAB) fermentation. LAB, primary source of probiotics, can produce additional immunomodulatory metabolites such as exopolysaccharides, short-chain fatty acids, and bacteriocins. Moreover, several compounds from herbal medicines can promote the growth and production of LAB-based immune active metabolites. Thus, LAB-mediated fermentation of herbal medicines has become a novel strategy for regulating human immune responses. The current review discusses the immunomodulatory properties and active compounds of LAB fermented herbal drugs, the interaction between LAB and herbal medicines, and changes in immunoregulatory components that occur during fermentation. This study also discusses the mechanisms by which LAB-fermented herbal medicines regulate the immune response, including activation of the innate or adaptive immune system and the maintenance of intestinal immune homeostasis.

Direct Action of Non-Digestible Oligosaccharides against a Leaky Gut

The epithelial monolayer is the primary determinant of mucosal barrier function, and tight junction (TJ) complexes seal the paracellular space between the adjacent epithelial cells and represent the main "gate-keepers" of the paracellular route. Impaired TJ functionality results in increased permeation of the "pro-inflammatory" luminal contents to the circulation that induces local and systemic inflammatory and immune responses, ultimately triggering and/or perpetuating (chronic) systemic inflammatory disorders. Increased gut leakiness is associated with intestinal and systemic disease states such as inflammatory bowel disease and neurodegenerative diseases such as Parkinson's disease. Modulation of TJ dynamics is an appealing strategy aiming at inflammatory conditions associated with compromised intestinal epithelial function. Recently there has been a growing interest in nutraceuticals, particularly in non-digestible oligosaccharides (NDOs). NDOs confer innumerable health benefits via microbiome-shaping and gut microbiota-related immune responses, including enhancement of epithelial barrier integrity. Emerging evidence supports that NDOs also exert health-beneficial effects on microbiota independently via direct interactions with intestinal epithelial and immune cells. Among these valuable features, NDOs promote barrier function by directly regulating TJs via AMPK-, PKC-, MAPK-, and TLR-associated pathways. This review provides a comprehensive overview of the epithelial barrier-protective effects of different NDOs with a special focus on their microbiota-independent modulation of TJs.

Effect of Selenium Nanoparticles and Mannan Oligosaccharide Supplementation on Growth Performance, Stress Indicators, and Intestinal Microarchitecture of Broilers Reared under High Stocking Density

The current study investigated the potential of selenium nanoparticles (SeNPs) and mannan-oligosaccharide (MOS) supplementation in ameliorating high stocking density (HSD) stress in broilers. A total of 392 day-old male chicks were divided into seven groups with eight replicates (n = 7): NSD [basal diet (BD) + normal stocking density: 10 bird/m2], HSD [BD + high stocking density: 16 bird/m2], Se−HSD [BD + Selenium (Se) 0.15 mg/kg], MOS−HSD (BD + MOS 5 gm/kg), Se−MOS−HSD (BD + Se 0.15 mg/kg and MOS 5 gm/kg), SeNPs−HSD (BD + SeNPs 0.15 mg/kg) and SeNPs−MOS−HSD (BD + SeNPs 0.15 mg/kg and MOS-5 gm/kg). HSD stress decreased (p < 0.05) weekly body weight and body weight gain and increased (p < 0.05) FCR compared to the NSD group. Supplementation with SeNPs and the SeNPs−MOS combination improved (p < 0.05) the weekly body weight and FCR in HSD-stressed broilers during the 5th and 6th weeks. On day 21, HSD stress decreased (p < 0.05) duodenal villus height (VH) and villus surface area (VSA) and increased (p < 0.05) serum corticosterone and cholesterol compared to the NSD group. Supplementation with the SeNPs−MOS combination increased (p < 0.05) duodenal VH and VH:CD, and jejunal total goblet cell (TGC) density and decreased (p < 0.05) serum corticosterone and cholesterol and ileal intra-epithelial lymphocyte (IEL) density in HSD-stressed broilers. On day 42, HSD stress decreased (p < 0.05) duodenal and jejunal VH, VSA, VH:CD, PCNA positive cell density and TGC density, Ileal VSA and TGC density, and increased (p < 0.05) serum cholesterol and ileal IEL density compared to the NSD group. Supplementation with the SeNPs−MOS combination increased (p < 0.05) spleen and bursa absolute weights, duodenal VH, VSA, VH:CD, PCNA positive cell density and jejunal VH, VH:CD, and decreased (p < 0.05) serum cholesterol and ileal IEL density in HSD-stressed broilers. Our findings signify that HSD is stressful for broilers particularly during the finishing phase. Supplementation with the SeNPs−MOS combination mitigated HSD stress by partially improving the gut microarchitecture, gut barrier function and performance indicators.

Microbiome-metabolome analysis reveals alterations in the composition and metabolism of caecal microbiota and metabolites with dietary Enteromorpha polysaccharide and Yeast glycoprotein in chickens

The intestinal microbiome is responsible for the fermentation of complex carbohydrates and orchestrates the immune system through gut microbiota-derived metabolites. In our previous study, we reported that supplementation of Enteromorpha polysaccharide (EP) and yeast glycoprotein (YG) in combination synergistically improved antioxidant activities, serum lipid profile, and fatty acid metabolism in chicken. However, the mechanism of action of these polysaccharides remains elusive. The present study used an integrated 16S-rRNA sequencing technology and untargeted metabolomics technique to reveal the mechanism of action of EP+YG supplementation in broiler chickens fed basal diet or diets supplemented with EP+YG (200mg/kg EP + 200mg/kg YG). The results showed that EP+YG supplementation altered the overall structure of caecal microbiota as evidenced by β diversities analysis. Besides, EP+YG supplementation changed the microbiota composition by altering the community profile at the phylum and genus levels. Furthermore, Spearman correlation analysis indicated a significant correlation between altered microbiota genera vs serum cytokine levels and microbiota genera vs volatile fatty acids production. Predicted functional analysis showed that EP+YG supplementation significantly enriched amino acid metabolism, nucleotide metabolism, glycan biosynthesis and metabolism, energy metabolism, and carbohydrate metabolism. Metabolomics analysis confirmed that EP+YG supplementation modulates a myriad of caecal metabolites by increasing some metabolites, including pyruvic acid, pyridoxine, spermidine, spermine, and dopamine, and decreasing metabolites related to lipid metabolisms such as malonic acid, oleic acid, and docosahexaenoic acid. The quantitative enrichment analysis results further showed that glycolysis/gluconeogenesis, citric acid cycle, tyrosine metabolism, glycine, serine, and threonine metabolism, and cysteine and methionine metabolism were the most important enriched pathways identified with enrichment ratio >11, whereas, fatty acid biosynthesis and biosynthesis of unsaturated fatty acids pathways were suppressed. Together, the 16S-rRNA and untargeted metabolomics results uncovered that EP+YG supplementation modulates intestinal microbiota and their metabolites, thereby influencing the important metabolism pathways, suggesting a potential feed additive.

Enteromorpha polysaccharide and yeast glycoprotein mixture improves growth, antioxidant activity, serum lipid profile and regulates lipid metabolism in broiler chickens

This study aimed to analyze the growth performance, antioxidant activity, serum lipid profile, meat quality, and lipid metabolism of broiler chickens fed mixtures containing Enteromorpha polysaccharide (EP) and yeast glycoprotein (YG). A total of 400 one-day-old broiler chickens were randomly divided into 4 treatment groups of 10 replicates with 10 birds each replicate. The dietary treatments consisted of the control group (fed basal diet), and diets supplemented with Enteromorpha polysaccharide (EP; 400 mg/kg), yeast glycoprotein (YG;400 mg/kg), and EP+YG (200 mg/kg EP + 200 mg/kg YG). Compared with the control group, EP+YG supplementation enhanced growth performance and significantly reduced (P < 0.05) serum total triglyceride (TG), cholesterol (CHOL), and low-density lipoprotein LDL levels, and increased high-density lipoprotein (HDL) levels. Besides, birds fed EP+YG supplemented diet exhibited higher (P < 0.05) serum catalase (CAT), total antioxidant capacity, superoxide dismutase (SOD), and lower malonaldehyde (MDA) activities, and upregulated expressions of related genes, such as nuclear factor-erythroid factor 2-related factor 2 (NRF2), SOD1, and glutathione peroxidase 4 (GPX4) in the liver and intestinal tissues than the control group. Interestingly, higher (P < 0.05) serum SOD and lower MDA contents were observed in the EP+YG group than in either EP or YG group, suggesting a synergetic effect. Breast meat from EP+YG supplemented group had significantly higher redness value (a*), and lower pH24, total saturated fatty acid profiles, C14:0, C16:0, C18:0 fatty acid, atherogenic index, and thrombogenicity index than meat from the control group (P < 0.05). Furthermore, the mRNA expressions of fatty acid synthesis genes were downregulated (P < 0.05), whereas lipid β-oxidation-related genes were upregulated (P < 0.05) in the liver of the EP+YG supplemented group than in the control group. Overall, our data suggest that dietary EP+YG inclusion may have a synergistic effect, and therefore improve growth performance, regulate serum biochemical indexes, enhance antioxidant activity, and modulate lipid metabolism in broilers, indicating that it is a potential feed additive for chickens.

Protective Effects and Potential Mechanisms of Dietary Resveratrol Supplementation on the Spleen of Broilers Under Heat Stress

Resveratrol (RSV) is a natural polyphenolic compound with potent antioxidant and anti-inflammatory properties. This study aimed to investigate the protective effects of RSV supplementation on the inflammatory responses of broilers during heat stress. A total of 432 28-d-old white-feathered broilers (817 crossbred chicken) with an average weight of 549 ± 4 g were randomly allotted to 4 equal groups (Half male and half female, 6 replicates/group, 18 chickens/replicate), including normal temperature (NT) group (24 ± 2°C for 24 h/d, basal diet), NT+RSV group (24 ± 2°C for 24 h/d, basal diet + RSV), heat stress (HT) group (37 ± 2°C for 8 h/d, basal diet), and HT+RSV group (37 ± 2°C for 8 h/d, basal diet + RSV). Serum samples were collected on d 7 and 14 of heat stress, and thymus, spleen, jejunum, and bursa of Fabricius samples were collected and analyzed on d14. RSV treatment decreased the feed conversion ratio, partially reversed the negative alternations in body weight, average daily gain, and average daily feed intake caused by heat stress. RSV treatment also decreased the elevated levels of corticosterone on d 14, adrenocorticotropic hormone, and triiodothyronine in serum on d 7 caused by heat stress, and significantly increased the villus height to crypt depth ratio in the jejunum on d 14. Dietary RSV also reduced heat stress-induced splenic pro-inflammatory cytokine concentrations. TUNEL assay showed that RSV significantly reduced heat stress-induced the number of apoptotic cells. Remarkably, RSV down-regulated some splenic related genes for apoptosis genes, including BCL-2, Apaf-1, and MDM2 mRNA levels induced by heat stress. According to GO and KEGG enrichment analyses, the differential genes between HT and HT + RSV groups were mainly associated with immune system process, hematopoietic or lymphoid organ development, and toll-like receptor signaling pathway. The relative mRNA expression of NF-κB, heat shock protein 70 (HSP70), and p38 MAPK were markedly decreased by the combination of RSV and heat stress. These findings showed that RSV might reduce the splenic inflammatory response in heat-stressed white-feather broilers by inhibiting heat stress-induced activation of NF-B, MAPK, and HSP70, as well as inhibiting the activation of mitochondrial apoptotic pathways.

Effect of Dietary Supplementation with Mannose Oligosaccharides on the Body Condition, Lactation Performance and Their Offspring of Heat-Stressed Sows

The aim of this study was to determine the effects of dietary supplementation with mannose oligosaccharide (MOS) on the condition of the body and the reproductive and lactation performances of sows. Eighty pregnant sows were randomly assigned to four groups with a 2 × 2 factorial design: with or without MOS (1 g/kg) and with or without heat stress (HS) challenge. The temperature in the HS groups (HS and HM group) was controlled at 31.56 ± 1.22 °C, while the temperature in the active cooling (AC) groups (AC and AM group) was controlled at 23.49 ± 0.72 °C. The weight loss of sows in the AC group was significantly lower than that of sows in the HS group (p < 0.01). The weight and backfat thickness loss of sows supplemented with MOS displayed a downward trend. The average birth weight of the litter significantly increased in the HM group (basic diet + MOS) compared with the HS group (p < 0.05). The milk protein of sows significantly decreased under the HS condition at 2 and 12 h after delivery (p < 0.05). However, the milk immunoglobin G (IgG) of sows in the HS group increased significantly compared with that of sows in the HM group (p < 0.05) at 12 and 24 h after delivery. The levels of serum urea nitrogen (UREA) and glucose (GLU) decreased significantly under the HS condition (p < 0.05), while the level of interleukin-6 (IL-6) increased significantly under the HS condition (p < 0.05). Dietary supplementation with MOS also significantly reduced TNF-α under the AC conditions (p < 0.05). In conclusion, HS significantly affected the body condition, lactation performances and their offspring of sows. However, dietary supplementation with 1 g/kg MOS did not result in statistically significant changes.

Seaweed-Derived Polysaccharides Attenuate Heat Stress-Induced Splenic Oxidative Stress and Inflammatory Response via Regulating Nrf2 and NF-κB Signaling Pathways

With global warming, heat stress (HS) has become a worldwide concern in both humans and animals. The ameliorative effect of seaweed (Enteromorpha prolifera) derived polysaccharides (SDP) on HS-induced oxidative stress and the inflammatory response of an immune organ (spleen) was evaluated using an animal model (Gallus gallus domesticus). In total, 144 animals were used in this 4-week trial and randomly assigned to the following three groups: thermoneutral zone, HS, and HS group supplemented with 1000 mg/kg SDP. Dietary SDP improved the antioxidant capacity and reduced the malondialdehyde (MDA) of the spleen when exposed to HS, regulated via enhancing nuclear factor erythroid 2-related factor-2 (Nrf2) signaling. Furthermore, the inclusion of SDP reduced the levels of pro-inflammatory cytokines and alleviated HS-induced splenic inflammatory response by suppressing the nuclear factor-kappa B (NF-κB) p65 signaling. These findings suggest that the SDP from E. prolifera can be used as a functional food and/or feed supplement to attenuate HS-induced oxidative stress and inflammatory responses of the immune organs. Moreover, the results could contribute to the development of high-value marine products from seaweed for potential use in humans and animals, owing to their antioxidant and anti-inflammatory effects.

Ellagic Acid Improves Antioxidant Capacity and Intestinal Barrier Function of Heat-Stressed Broilers via Regulating Gut Microbiota

Heat stress (HS) has been revealed to damage the antioxidant system and intestinal barrier function, which greatly threatens poultry production. The present study investigated the effects of dietary ellagic acid (EA) on the antioxidant system, gut barrier function, and gut microbiota of heat-stressed broilers. Arbor Acres 14-day-old broilers numbering 360 were randomly divided into six groups, including one negative control group (NC) and five experimental groups. The broilers in the NC group were supplemented with a basal diet at a normal temperature (23 ± 2 °C). The broilers in the experimental groups were supplemented with basal diets containing EA at different doses (0, 75, 150, 300, and 600 mg/kg) at HS temperature (35 ± 2 °C). The experiment lasted for 4 weeks. Results showed that dietary EA reduced the corticosterone (CORT), LPS, and diamine oxidase (DAO) levels in the serum of heat-stressed broilers. Additionally, dietary EA improved the antioxidant enzyme activity and mRNA levels of Nrf2/HO-1 in the ileum of heat-stressed broilers. The relative abundances of Streptococcus, Ruminococcus_torques, Rothia, Neisseria, Actinomyces, and Lautropia in the cecum were significantly reduced by the EA supplementation in a dose-dependent manner. Notably, the LPS, DAO, and MDA in the serum were revealed to be positively correlated with the relative abundances of Rothia, Neisseria, Actinomyces, and Lautropia, while the GSH-px, SOD, and CAT levels in the serum were negatively correlated with the relative abundances of Ruminococcus_torques, Rothia, Neisseria, Actinomyces, Streptococcus, and Lautropia. Taken together, dietary EA improved the antioxidant capacity, intestinal barrier function, and alleviated heat-stressed injuries probably via regulating gut microbiota.

Influence of heat stress on intestinal integrity and the caecal microbiota during Enterococcus cecorum infection in broilers

Enterococcus cecorum (EC) is one of the most relevant bacterial pathogens in modern broiler chicken production from an economic and animal welfare perspective. Although EC pathogenesis is generally well described, predisposing factors are still unknown. This study aimed to understand the effect of heat stress on the caecal microbiota, intestinal integrity, and EC pathogenesis. A total of 373 1-day-old commercial broiler chicks were randomly assigned to four groups: (1) noninoculated, thermoneutral conditions (TN); (2) noninoculated, heat stress conditions (HS); (3) EC-inoculated, thermoneutral conditions (TN + EC); and (4) EC-inoculated, heat stress conditions (HS + EC). Birds were monitored daily for clinical signs. Necropsy of 20 broilers per group was performed at 7, 14, 21, and 42 days post-hatch (dph). A trend towards enhanced and more pronounced clinical disease was observed in the EC-inoculated, heat-stressed group. EC detection rates in extraintestinal tissues via culture were higher in the HS + EC group (~19%) than in the TN + EC group (~11%). Significantly more birds were colonized by EC at 7 dph in the HS + EC group (100%) than in the TN + EC group (65%, p < 0.05). The caecal microbiota in the two EC-inoculated groups was significantly more diverse than that in the TN group (p < 0.05) at 14 dph, which may indicate an effect of EC infection. An influence of heat stress on mRNA expression of tight junction proteins in the caecum was detected at 7 dph, where all six investigated tight junction proteins were expressed at significantly lower levels in the heat stressed groups compared to the thermoneutral groups. These observations suggest that heat stress may predispose broilers to EC-associated disease and increase the severity thereof. Furthermore, heat stress may impair intestinal integrity and promote EC translocation.

Copper/Zinc-Modified Palygorskite Protects Against Salmonella Typhimurium Infection and Modulates the Intestinal Microbiota in Chickens

Palygorskite (Pal), a clay nanoparticle, has been demonstrated to be a vehicle for drug delivery. Copper has antibacterial properties, and zinc is an essential micronutrient for intestinal health in animals and humans. However, whether copper/zinc-modified Pal (Cu/Zn-Pal) can protect chickens from Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infection remains unclear. In this study, three complexes (Cu/Zn-Pal-1, Cu/Zn-Pal-2, and Cu/Zn-Pal-3) were prepared, and Cu/Zn-Pal-1 was shown to be the most effective at inhibiting the growth of S. Typhimurium in vitro, whereas natural Pal alone had no inhibitory effect. In vivo, Cu/Zn-Pal-1 reduced S. Typhimurium colonization in the intestine of infected chickens and relieved S. Typhimurium-induced organ and intestinal mucosal barrier damage. Moreover, this reduction in Salmonella load attenuated intestinal inflammation and the oxidative stress response in challenged chickens. Additionally, Cu/Zn-Pal-1 modulated the intestinal microbiota in infected chickens, which was characterized by the reduced abundance of Firmicutes and the increased abundance of Proteobacteria and Bacteroidetes. Our results indicated that the Cu/Zn-Pal-1 complex may be an effective feed supplement for reducing S. Typhimurium colonization of the gut.

Administration of Dietary Microalgae Ameliorates Intestinal Parameters, Improves Body Weight, and Reduces Thawing Loss of Fillets in Broiler Chickens: A Pilot Study

This pilot investigation aimed at studying the feasibility of using a low dose (0.2%) of dietary microalgae as a means of improving intestinal morphometry, body weight, and selected meat quality parameters in broilers. A total of 72 one-day-old ROSS 308 male chicks were randomly separated into four groups; three experimental pens in which the birds were fed with biomass from Tysochrysis lutea, Tetraselmis chuii, and Porphyridium cruentum over 30 days and a control group. T. chuii and P. cruentum had a positive effect with regard to body weight. In treated animals, duodenal and ileal sections showed characteristic tall and thin villi, with serrated surfaces and goblet cell differentiation. In both sections, values of the villus-height-to-crypt-depth ratio were increased by microalgae ingestion. The thawing weight loss of fillets was reduced in T. chuii-fed animals. The positive effects exerted by T. chuii and P. cruentum on intestinal architecture were associated with the improved body weight. Arguably, these outcomes exhibit the potential of using these species to enhance growth performance in broiler chickens by promoting gut homeostasis and thus nutrient absorption.

The Effect of Adding Herbal Extracts to Drinking Water on Body Temperature, Level of Thyroid Hormones and H:L Ratio in the Blood of Broiler Chickens Exposed to Elevated Ambient Temperature

The aim of the study was to determine the effect of supplementing drinking water with extracts from lemon balm, sage and nettle on body temperature, level of thyroid hormones and the heterophil to lymphocyte (H:L) ratio in the blood of broiler chickens exposed to elevated rearing temperature. One-day-old Ross 308 chicks were divided into four groups: group I (CON) and experimental groups II (LB), II (S) and IV (N), in which, from 22 to 42 days of rearing, drinkers were supplemented with lemon balm extract, sage extract or nettle extract (2 ml/l water), respectively. In addition, at 5 weeks of growth, all the groups were exposed to elevated ambient temperature (up to 30°C) for 5 days, after which the recommended thermal conditions were reinstated. During the study, mortality, rectal temperature and radiated temperature of the broilers were monitored. Blood was collected from 10 birds per group to determine the concentration of thyroid hormones (T3 and T4) and to make blood smears. The H:L ratio was determined based on the percentage of heterophils (H) and lymphocytes (L). The herbal extracts from lemon balm, sage and nettle, added to drinking water at 2 ml/l, reduced the blood level of the thyroid hormone (triiodothyronine) and rectal temperature in the experimental broilers during the initial period of thermal stress. Chickens receiving the nettle extract were also characterised by lower radiated temperature of the unfeathered body, a lower H:L ratio in the blood during the increase in ambient temperature, and the lowest mortality percentage. It can therefore be considered that the dietary supplementation of nettle, in the form and concentration used in this study, had the most favourable effect on the physiological status of the birds (body temperature, level of thyroid hormones and H:L ratio) exposed to elevated ambient temperatures (30°C), and thus on their welfare.

Resveratrol sustains intestinal barrier integrity, improves antioxidant capacity, and alleviates inflammation in the jejunum of ducks exposed to acute heat stress

Resveratrol, a natural antioxidant, anti-inflammatory plant extract, was found to have a protective effect in poultry subjected to heat stress. In this study, we strove to characterize resveratrol on intestinal of duck exposed to acute heat stress and investigate the underlying mechanism. A total of 120 Shan-ma ducks (60 days old) were randomly divided into 2 groups. The control group was fed a basal diet, and the resveratrol group was fed a basal diet supplemented with 400 mg/kg resveratrol. Animals in 2 groups were kept at a temperature of 24°C ± 2°C for 15 d. Then, animals of both groups were placed in an artificial climate room at 39°C. Twelve ducks of each group were sacrificed for sampling at 0, 30, and 60 min, respectively. Results indicated that resveratrol increased the ratio of villus height to crypt depth, increased the number of goblet cells, and reduced the histopathological damage of jejunum caused by acute heat stress. Furthermore, the gene expression of heat shock proteins (HSP60, HSP70, and HSP90) and tight junction proteins (CLDN1 and OCLN) was significantly increased in the resveratrol group compared to that in the control groups. Simultaneously, resveratrol significantly activated the SIRT1-NRF1/NRF2 signaling pathways, improved ATP level of jejunum, and increased SOD and CAT antioxidant enzymes activities. In addition, we found that the NF-κB/NLRP3 inflammasome signaling pathways were repressed under acute heat stress. Meanwhile, supplement resveratrol further inhibited the NLRP3 inflammasome pathway, decreased protein level of NLRP3 and caspase1 p20, reduced the secretion of IL-1β. Taken together, our results indicate that resveratrol against the oxidative damage and inflammation injury in duck jejunum induced by heat stress via active SIRT1 signaling pathways.

Mannan Oligosaccharide Could Attenuate Ochratoxin A-Induced Immunosuppression with Long-Time Exposure Instead of Immunostimulation with Short-Time Exposure

Our previous study showed that ochratoxin A (OTA), one of the most common mycotoxins in feed, could induce immunosuppression with long-time exposure but immunostimulation with short-time exposure. However, limited studies for the control of OTA-induced two-way immune toxicity were carried out. This study explored the effects of mannan oligosaccharide (MOS), a glucomannoprotein complex with immunoregulatory capability derived from the yeast cell wall, on OTA-induced immune toxicity and its underlying mechanisms. Surprisingly, the results showed that MOS significantly attenuated immunosuppression induced by long-time OTA treatment but did not provide protection against immunostimulation induced by short-time OTA treatment on porcine alveolar macrophages (PAMs), as demonstrated by the expressions of inflammatory cytokines and the capability of migration and phagocytosis. Further, MOS increased the OTA-inhibited autophagy level and the JNK phosphorylation level on PAMs with long-time OTA treatment. In addition, the inhibition of autophagy by 3-MA or the inhibition of JNK phosphorylation by SP600125 could partly block the protective effects of MOS on OTA-induced immunosuppression. Importantly, the inhibition of JNK phosphorylation down-regulated the MOS-promoted autophagy level. In conclusion, MOS could attenuate OTA-induced immunosuppression with short-time exposure on PAMs through activating JNK-mediated autophagy but had no significant effects on OTA-induced immunostimulation with short-time exposure. Our study provides new insights into the application of MOS as an immunoregulator against mycotoxin-induced immune toxicity.

Comparative effects of dietary functional nutrients on growth performance, meat quality, immune responses, and stress biomarkers in broiler chickens raised under heat stress conditions

Objective

The objective of the present study was to investigate the comparative effects of dietary functional nutrients including glutamine (Gln), chromium picolinate (Cr picolinate), vitamin C (Vit C), betaine (Bet), and taurine (Tau) on growth performance, meat quality, immune responses, and stress biomarkers in broiler chickens raised under heat stress conditions.

Methods

A total of 420 21-d-old Ross 308 male broiler chickens (initial body weight = 866±61.9 g) were randomly allotted to 1 of 7 treatment groups with 6 replicates. One group was kept under thermoneutral conditions and was fed a basal diet (PC, positive control). Other 6 groups were exposed to a cyclic heat stress condition. One of the 6 groups was fed the basal diet (NC, negative control), whereas 5 other groups were fed the basal diet supplemented with 0.5% Gln, 500 ppb Cr picolinate, 250 mg/kg Vit C, 0.2% Bet, or 1.0% Tau. The diets and water were provided ad libitum for 21 d.

Results

Broiler chickens in NC group had decreased (p<0.05) growth performance and immune responses measured based on cutaneous basophil hypersensitivity (CBH), but increased (p<0.05) stress responses measured based on feather corticosterone concentrations and blood heterophil:lymphocyte than those in PC group. However, none of dietary functional nutrients had a positive effect on growth performance of broiler chickens. Dietary supplementation of 250 mg/kg Vit C improved (p<0.05) CBH responses of broiler chickens, but other functional nutrients had no such an improvement in CBH responses. All functional nutrients decreased (p<0.05) stress responses of broiler chickens.

Conclusion

Functional nutrients including Gln, Cr picolinate, Vit C, Bet, and Tau at the supplemental levels used in this study decrease stress responses of broiler chickens to a relatively similar extent. However, this reduction in stress responses could not fully ameliorate decreased productive performance of broiler chickens raised under the current heat stress conditions.

Dietary Mannanoligosaccharide Supplementation Improves Growth Performance, Intestinal Integrity, Serum Immunity, and Antioxidant Capacity of Partridge Shank Chickens

Herein, we assessed the impact of dietary addition of konjac mannanoligosaccharide (MOS) on the growth, intestinal morphology, serum immune status, and oxidative status in Partridge Shank chickens. For the experiment, one-day-old chicks (n=192) were randomized into six replicates (n=8/replicate) and fed four different diets: a basal diet containing 0 (Control group), 0.5, 1, or 1.5 g MOS per kg of diet (g/kg) for 50 d. Relative to the control, the group fed 0.5 g/kg MOS decreased feed consumption from 22^nd to 50^th d and 1^st to 50^th d (P<0.05). By adding MOS, the height of the intestinal villus and the villus height to crypt depth ratio were increased (P<0.05); 1.5 g/kg MOS was the best dosage for these parameters. Jejunal and ileal goblet cell density increased following MOS supplementation at 21 d (P<0.01) and 50 d in the jejunum (P<0.05), respectively. Moreover, adding MOS to the diet increased the contents of IgA and IgM at 21 d (P<0.05) and total antioxidant capacity (P<0.05) at 50 d in the serum but decreased malondialdehyde content (P<0.01) at 21 d in the group fed 0.5 and 1.5 g/kg MOS. The findings suggested that MOS supplementation could affect feed consumption, intestinal health, serous immunity, and antioxidant capacity of Partridge Shank chickens.

Effect of heat stress on growth and production performance of livestock and poultry: Mechanism to prevention

Heat stress is a widespread phenomenon in domestic animal feeding in tropical and sub-tropical areas that are subjected to a growing negative effect in livestock and poultry due to global warming. It leads to reduced food intake, retarded growth, intestinal disequilibrium, lower reproductive performance, immunity and endocrine disorders in livestock and poultry. Many studies show that the pathogenesis of heat stress is mainly related to oxidative stress, hormone secretion disorder, cytokine imbalance, cell apoptosis, cell autophagy, and abnormal cell function. Its mechanism refers to activation of mitogen-activated protein kinase (MAPK) signaling pathway and nuclear factor kappa B (NF-κB) signaling pathway, the fluctuation of tight junction protein and heat shock protein expression, and protein epigenetic modification. This manuscript reviews the mechanism of heat stress through an insight into the digestive, reproductive, immune, and endocrine system. Lastly, the progress in prevention and control techniques of heat stress has been summarized.

Effect of chlorogenic acid on intestinal inflammation, antioxidant status, and microbial community of young hens challenged with acute heat stress

Heat stress in poultry is deleterious to productive performance. Chlorogenic acid (CGA) exerts antibacterial, anti-inflammatory, and antioxidant properties. This study was conducted to evaluate the effects of dietary supplemental CGA on the intestinal health and cecal microbiota composition of young hens challenged with acute heat stress. 100-day-old Hy-line brown pullets were randomly divided into four groups. The control group (C) and heat stress group (HS) received a basal diet. HS + CGA₃₀₀ group and HS + CGA₆₀₀ group received a basal diet supplemented with 300- and 600-mg/kg CGA, respectively, for 2 weeks before heat stress exposure. Pullets of HS, HS + CGA₃₀₀ , and HS + CGA₆₀₀ group were exposed to 38°C for 4 h while the control group was maintained at 25°C. In this study, dietary CGA supplementation had effect on mitigate the decreased T-AOC and T-SOD activities and the increasing of IL-1β and TNFα induced by acute heat stress. Dietary supplementation with 600 mg/kg CGA had better effect on increasing the relative abundance of beneficial bacterial genera, such as Rikenellaceae RC9_gut_group, Ruminococcaceae UCG-005, and Christensenellaceae R-7_group, and deceasing bacteria genera involved in inflammation, such as Sutterella species. Therefore, CGA can ameliorate acute heat stress damage through suppressing inflammation and improved antioxidant capacity and cecal microbiota composition.

Effects of Dietary Supplementation of Algae-Derived Polysaccharides on Morphology, Tight Junctions, Antioxidant Capacity and Immune Response of Duodenum in Broilers under Heat Stress

Simple Summary

Heat stress (HS) has become a great challenge for poultry production in tropical and subtropical regions. HS results in the intestinal dysfunction of broilers, which seriously affects their productivity. Our previous study suggested that dietary supplementation of algae-derived polysaccharides (ADP) could promote the intestinal barrier function in broilers, but the effect of dietary ADP supplementation on the intestinal health of broilers under HS remains unclear. The present study showed that dietary ADP supplementation improved the duodenal tight junction expression of broilers under HS, and found that dietary ADP mitigated HS-induced oxidative stress and inflammation response by regulating Nrf2 and NF-κB signaling pathways. These findings reveal the potential application of ADP as an HS-alleviating agent to maintain gut health in broilers.

Abstract

To evaluate the ameliorative effect of algae-derived polysaccharide (ADP) supplementation on duodenal injury caused by heat stress (HS) in broilers, a total of 144 male yellow-feathered broilers (56-day-old) were randomly allocated into three groups: The TN group (thermoneutral zone, broilers were raised at 23.6 ± 1.8 °C); HS group (heat stress, broilers were exposed to 33.2 ± 1.5 °C 10 h/day, 8:00 a.m.–18:00 p.m., the temperature in the remaining period was consistent with the TN group); HSA group (heat-stressed broilers were fed with ADP supplemented diet at 1000 mg/kg). There were six replications in each treatment, and eight broilers in each replication. The feeding trial lasted four weeks. The results showed that dietary ADP supplementation tended to increase the villus height (p = 0.077) and villus width (p = 0.062), and decrease the apoptosis rate (p = 0.081) in the duodenum of broilers under HS. Furthermore, dietary ADP increased the relative mRNA and protein (based on immunofluorescence) expression levels of occludin and zonula occludens-1 (ZO-1) in the duodenum of broilers under HS (p < 0.05). In addition, dietary ADP enhanced the total antioxidation capacity (T-AOC) and activity of glutathione-S transferase (GST), while reducing the malondialdehyde (MDA) concentration of the duodenum in broilers under HS (p < 0.05). Moreover, dietary ADP supplementation upregulated the duodenal nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), glutathione peroxidase 1 (GPx1) and glutathione S-transferase theta 1 (GSTT1) mRNA expression levels in heat-stressed broilers (p < 0.05). Furthermore, compared with the HS group, broilers fed with an ADP supplemented diet had a higher relative mRNA expression of inhibitor kappa B alpha (IκBα) (p < 0.05) and a lower relative mRNA expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the duodenum (p < 0.05). In summary, dietary ADP supplementation had an ameliorative effect on HS-induced impairment of tight junctions, antioxidant capacity and the immune response of the duodenum in broilers. These beneficial effects might be related to the modulation of Nrf2 and NF-κB signaling pathways.

Protective influence of betaine on intestinal health by regulating inflammation and improving barrier function in broilers under heat stress

This research was executed to study the impacts of adding betaine (BT) to broiler diets on intestinal inflammatory response and barrier integrity under heat stress (HS). At 21 d of age, 150 male broilers (Ross 308) were randomly assigned to 3 treatment groups: control (CON) group, in which broilers were provided standard finisher feed under thermoneutral condition (22 ± 1°C); HS group and HS + BT group, in which broilers were given the standard feed supplied with 0 and 1,000 mg/kg BT, respectively, under cyclic HS condition (33 ± 1°C for 8 h from 08:00 to 16:00 h and the thermoneutral temperature for the residual hours). Each treatment was replicated ten times with 5 broilers per replicate. The HS group showed an elevation (P < 0.05) in serum corticosterone (CORT) concentration, D-lactate acid (D-LA) content, and diamine oxidase (DAO) activity, mucosal interleukin-1β (IL-1β) level, and expression of heat shock protein 70 (HSP70) gene, and a reduction (P < 0.05) in mucosal interleukin-10 (IL-10) level and secretory immunoglobulin A (SIgA) content and relative abundance of mRNA for occludin (OCLN), zonula occludens-1 (ZO-1), claudin-1 (CLDN1), and claudin-4 (CLDN4). In contrast, broilers in the HS + BT group exhibited a raise (P < 0.05) in mucosal IL-10 level and SIgA content and relative expression of OCLN and ZO-1 genes, and a decline (P < 0.05) in serum CORT concentration and DAO activity, mucosal IL-1β level, and expression of HSP70 mRNA. These results indicate that supplemental BT can ameliorate intestinal injury in heat-challenged broilers by suppressing inflammatory responses and enhancing mucosal barrier function.

Interactive effects of dietary amino acid density and environmental temperature on growth performance and expression of selected amino acid transporters, water channels, and stress-related transcripts

Exposure to heat stress (HS) is one of the challenges facing the broiler industry worldwide. Various nutritional strategies have been suggested, such as altering dietary concentrations of some nutrients. Thus, we evaluated feeding different amino acid (AA) densities on live performance, Pectoralis (P.) muscles, and expression of selected AA transporters, water channels, and stress-related transcripts in a fast-growing broiler strain. Ross 308 chicks (n = 576) were randomly assigned to 4 dietary treatments (24 reps, 6 chicks per rep), differing in AA density (110, 100, 90, and 80% of a breeder's AA specifications). During 24 to 36 days of age, half of the birds were kept at a thermoneutral (TN) temperature of 20°C, whereas the other half were subjected to HS at 32° C for 8 h daily, making the treatment design a 4 × 2. The results revealed no interaction between housing temperature and AA density on growth performance or P. muscles weights. Feeding 80% AAs depressed BWG, FCR, and P. muscles at 36 d (P < 0.001). There was an interaction (P < 0.001) between AA density and temperature on the expression of all examined genes. Reducing the AA density beyond 100% upregulated the expression of AA transporter (CAT1, B⁰AT, b^0,+AT, SNAT1, LAT1), HSP70, HSP90, glucocorticoid receptor (GR), and AQP3 in the TN birds’ jejunum. Whereas in the HS birds, inconsistent expressions were observed in the jejunum, of which CAT1, B⁰AT, and LAT1 were markedly downregulated as AA density was reduced. In P. major of TN birds, reducing AA density resulted in upregulating the expression of all AA transporters, HSP70, GR, and AQP1, while downregulating HSP90 and AQP9. In contrast, AA reduction markedly downregulated CAT1, B⁰AT, and LAT1 in the P. major of HS birds. These findings indicate that the dietary AA level alters the expression of various genes involved in AA uptake, protein folding, and water transport. The magnitude of alteration is also dependent on the housing temperature. Furthermore, the results highlight the importance of adequate AA nutrition for fast-growing chickens under HS.

Molecular and morphometric changes in the small intestine during hot and cold exposure in thermally manipulated broiler chickens

Background and Aim:

Thermal stress (hot or cold) is one of many environmental stressors that severely affects the health of broiler chickens. One negative effect of thermal stress is the disruption of the intestinal barrier function in broiler chickens. This study aimed to evaluate the effect of thermal manipulation (TM) on the small intestine in terms of histomorphometry as well as junctional, heat-shock, and immune response gene expression during post-hatch exposure to thermal stress.

Materials and Methods:

The experiment was conducted by dividing 928 fertile Ross eggs into three incubation groups: The control (C) group (incubated at 37.8°C and 56% relative humidity [RH] for the whole incubation period), the TM using low temperature TML group (incubated at 36°C and 56% RH for 18 h/day from embryonic days 7 to 16), and the TM using high temperature (TMH) group (incubated at 39°C and 65% RH for 18 h/day from embryonic days 7 to 16). On post-hatch day 21, 90 chicks were randomly selected from each incubation group and were equally subdivided into three subgroups for the post-hatch thermal stress experiment: The TN subgroup (room temperature maintained at 24°C), the heat stress (HS) subgroup (room temperature maintained at 35°C), and the cold stress (CS) subgroup (room temperature maintained at 16°C). After 1 day of thermal stress exposure (age 22 days), five birds from each subgroup were euthanized and ileum samples were collected to evaluate the transcription of the Claudin (CLDN1), CLDN-5, Occludin, Cadherin-1, heat shock factors (HSF1), HSF3, 70 kilodalton heat shock protein, 90 kilodalton heat shock protein, Interleukin6 (IL6), IL8, toll-like receptors-2 (TLR2), and TLR4 genes by Real-Time Quantitative Reverse Transcription polymerase chain reaction analysis. Finally, after 4 and 7 days of thermal stress (age 25 and 28 days, respectively), nine chicks were euthanized, and their jejunum and ileum were collected for histomorphometric analysis.

Results:

After exposure to 1 day of thermal stress, the C subgroups exposed to thermal stress (HS and CS) possessed significantly increased expression of junctional, heat-shock, and immune response genes compared to the C-TN subgroup, and similar results were observed for the TMH. In contrast, thermally stressed TMH subgroups had significantly lower expression of the studied genes compared to C subgroups exposed to thermal stress. Furthermore, no significant changes were detected between the TML subgroups exposed to thermal stress and TML-TN. Moreover, significant alterations in villus height (VH), villus surface area, crypt depth (CD), and VH to CD ratio were observed between the TML, TMH, and C subgroups exposed to CS.

Conclusion:

It might be suggested that TM may have a protective impact on the small intestine histomorphometry and epithelial integrity of broilers during post-hatch exposure to thermal stress.

Protective effects of dietary synbiotic supplementation on meat quality and oxidative status in broilers under heat stress

This study evaluated protective effects of synbiotic on meat quality and oxidative status of breast muscle in heat-stressed broilers. Twenty 2-day-old broilers were allocated in a 2×2 factorial design, and the main factors consisted of synbiotic level (0 (basal diet) or 1.5 g/kg synbiotic) and temperature (thermoneutral or high temperature), resulting in 4 treatments. From 22 to 42 days, chickens were raised at thermoneutral temperature (22 °C) or subjected to cyclic high temperature (heat stress, HS) by keeping them at 32-33 °C for 8 h and 22 °C for rest 16 h daily. Cyclic HS decreased relative weight, redness (45 min), and pH values (45 min and 24 h) but increased contents of moisture and ether extract, lightness (45 min and 24 h), drip loss (24 h and 48 h), and cooking loss in breast muscle of broilers compared with those under thermoneutral temperature. It also increased malondialdehyde content and mRNA abundances of heat shock protein 70 (HSP70) and HSP90 but decreased glutathione (GSH) concentration and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as mRNA abundances of nuclear factor (erythroid 2)-like 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), GSH-Px, and copper and zinc superoxide dismutase in breast muscle in broilers. Dietary synbiotic supplementation was effective in increasing weight and reducing lightness (45 min), drip loss (24 h and 48 h) and cooking loss of breast muscle in heat-stressed broilers compared with those fed the basal diet. It also reduced malondialdehyde content and HSP70 mRNA abundance and increased GSH-Px activity, GSH content, and mRNA abundances of Nrf2, NQO1 and GSH-Px in breast muscle of heat-stressed broilers. These results suggested that synbiotic supplementation at a level of 1.5 g/kg could ameliorate compromised meat quality and oxidative status in broilers under cyclic HS.

The modulatory effects of alfalfa polysaccharide on intestinal microbiota and systemic health of Salmonella serotype (ser.) Enteritidis-challenged broilers

Salmonella serotype (ser.) Enteritidis infection in broilers is a main foodborne illness that substantially threatens food security. This study aimed to examine the effects of a novel polysaccharide isolated from alfalfa (APS) on the intestinal microbiome and systemic health of S. ser. Enteritidis-infected broilers. The results indicated that broilers receiving the APS-supplemented diet had the improved (P < 0.05) growth performance and gut health than those fed no APS-supplemented diet. Supplementation with APS enhanced (P < 0.05) the richness of gut beneficial microbes such as Bacteroidetes, Barnesiella, Parabacteroides, Butyricimonas, and Prevotellaceae, while decreased (P < 0.05) the abundance of facultative anaerobic bacteria including Proteobacteria, Actinobacteria, Ruminococcaceae, Lachnospiraceae, and Burkholderiaceae in the S. ser. Enteritidis-infected broilers. The Bacteroides and Odoribacter were identified as the two core microbes across all treatments and combined with their syntrophic microbes formed the hub in co-occurrence networks linking microbiome structure to performance of broilers. Taken together, dietary APS supplementation improved the systemic health of broilers by reshaping the intestinal microbiome regardless of whether S. ser. Enteritidis infection was present. Therefore, APS can be employed as a potential functional additives to inhibit the S. ser. Enteritidis and enhance the food safety in poultry farming.

Heat stress on microbiota composition, barrier integrity, and nutrient transport in gut, production performance, and its amelioration in farm animals

Livestock species experience several stresses, particularly weaning, transportation, overproduction, crowding, temperature, and diseases in their life. Heat stress (HS) is one of the most stressors, which is encountered in livestock production systems throughout the world, especially in the tropical regions and is likely to be intensified due to global rise in environmental temperature. The gut has emerged as one of the major target organs affected by HS. The alpha- and beta-diversity of gut microbiota composition are altered due to heat exposure to animals with greater colonization of pathogenic microbiota groups. HS also induces several changes in the gut including damages of microstructures of the mucosal epithelia, increased oxidative insults, reduced immunity, and increased permeability of the gut to toxins and pathogens. Vulnerability of the intestinal barrier integrity leads to invasion of pathogenic microbes and translocation of antigens to the blood circulations, which ultimately may cause systematic inflammations and immune responses. Moreover, digestion of nutrients in the guts may be impaired due to reduced enzymatic activity in the digesta, reduced surface areas for absorption and injury to the mucosal structure and altered expressions of the nutrient transport proteins and genes. The systematic hormonal changes due to HS along with alterations in immune and inflammatory responses often cause reduced feed intake and production performance in livestock and poultry. The altered microbiome likely orchestrates to the hosts for various relevant biological phenomena occurring in the body, but the exact mechanisms how functional communications occur between the microbiota and HS responses are yet to be elucidated. This review aims to discuss the effects of HS on microbiota composition, mucosal structure, oxidant-antioxidant balance mechanism, immunity, and barrier integrity in the gut, and production performance of farm animals along with the dietary ameliorations of HS. Also, this review attempts to explain the mechanisms how these biological responses are affected by HS.

Algae-derived polysaccharides supplementation ameliorates heat stress-induced impairment of bursa of Fabricius via modulating NF-κB signaling pathway in broilers

This study aimed to investigate the protective effects of dietary algae-derived polysaccharides (ADP) from Enteromorpha prolifera against heat stress (HS)-induced bursa of Fabricius injure in broilers, and to elucidate the molecular mechanisms underlying the protective effect. A total of 144 8-week-old male yellow-feathered broilers were randomly allocated into 3 treatments of 6 replicates each (8 broilers per replicate): thermoneutral zone group (TN, fed basal diet); heat stress group (HS, fed basal diet); heat stress + ADP group (HSA, basal diet supplemented with 1,000 mg/kg ADP). Broilers in TN group were raised at 23.6 ± 1.8°C during the whole study. Broilers in HS and HSA groups were exposed to 33.2 ± 1.5°C for 10 h/day. The experimental period lasted for four weeks. The results showed that HS and dietary ADP had no significant effects on bursa of Fabricius index (P > 0.05). HS exposure increased the apoptosis rate of bursa of Fabricius (P < 0.05), and the apoptosis rate was reduced by dietary ADP (P < 0.05). Besides, broilers in HS and HSA groups had a lower glutathione-S transferase (GST) activity and total anti-oxidation capacity (T-AOC), whereas had a higher malondialdehyde (MDA) levels of bursa of Fabricius than those in TN group (P < 0.05). HS exposure elevated the concentration of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-4, and IL-6, while decreased the concentration of interferon-γ (INF-γ) and IL-2 (P < 0.05), and dietary inclusion of ADP reduced the IL-1β level and increased the IL-2 level of bursa of Fabricius (P < 0.05). Compared with TN group, broilers in HS and HSA groups had lower relative mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and GSTT1 in bursa of Fabricius (P < 0.05). Additionally, HS exposure down-regulated the mRNA expression of inhibitor kappa B alpha (IκBα), IFN-γ, and IL-2, while up-regulated the mRNA expression of nuclear factor-kappa B (NF-κB) p65, TNF-α, IL-1β, and IL-6 in bursa of Fabricius (P < 0.05). However, dietary inclusion of ADP up-regulated the mRNA expression of IκBα and down-regulated the mRNA expression of NF-κB p65, TNF-α, and IL-6 in bursa of Fabricius (P < 0.05). Furthermore, HS exposure increased the relative protein expression levels of total and nuclear NF-κB p65 (P < 0.05), but dietary ADP supplementation reduced the relative protein expression levels of total and nuclear NF-κB p65 in bursa of Fabricius (P < 0.05). Collectively, dietary ADP ameliorated the impairment of histology, cell apoptosis and immune balance in bursa of Fabricius of heat stressed broilers, which is involved in modulation of NF-κB signaling pathway.

Effects of chitosan oligosaccharides on intestinal oxidative stress and inflammation response in heat stressed rats

This study was to verify the effects of chitosan oligosaccharides (COS) on intestinal integrity, oxidative status, and inflammatory response in a heat-stressed rat model. A total of 24 male Sprague Dawley rats were randomly divided into 3 treatment: CON, the control group; HS, the heat stress group; HSC, the heat stress group with 200 mg/kg COS. Rats in the HS and HSC group exposed to a cyclical heat stress for 7 consecutive days. The CON and HS group provided basal diet, and the HSC group provided the same diet with 200 mg/kg COS. Compared with the HS group, rats in the HSC group had lower serum diamine oxidase and D-lactate acid level, higher villus height of jejunum and ileum, lower malondialdehyde (MDA) content in duodenum, jejunum, and ileum mucosa, higher glutathione peroxidase (GSH-Px), catalase (CAT) and total antioxidant capacity (T-AOC) activity in duodenum mucosa, higher T-AOC activity in jejunum mucosa, and higher glutathione (GSH) level in ileum mucosa. Compared with the HS group, rats in the HSC group had higher interleukin-10 (IL-10) level, but lower tumor necrosis factor-α (TNF-α) level in duodenum, jejunum, and ileum mucosa. These results indicated that COS may alleviate intestinal damage under heat stress condition, probably by modulating intestinal inflammatory response and oxidative status.

The Protect Effects of Chitosan Oligosaccharides on Intestinal Integrity by Regulating Oxidative Status and Inflammation under Oxidative Stress

The aim of this study was to evaluate the effects of the dietary supplementation of chitosan oligosaccharides (COS) on intestinal integrity, oxidative status, and the inflammation response with hydrogen peroxide (H₂O₂) challenge. In total, 30 rats were randomly assigned to three groups with 10 replications: CON group, basal diet; AS group, basal diet + 0.1% H₂O₂ in drinking water; ASC group, basal diet + 200 mg/kg COS + 0.1% H₂O₂ in drinking water. The results indicated that COS upregulated (p < 0.05) villus height (VH) of the small intestine, duodenum, and ileum; mucosal glutathione peroxidase activity; jejunum and ileum mucosal total antioxidant capacity; duodenum and ileum mucosal interleukin (IL)-6 level; jejunum mucosal tumor necrosis factor (TNF)-α level; duodenum and ileum mucosal IL-10 level; the mRNA expression level of zonula occludens (ZO)-1 in the jejunum and ileum, claudin in the duodenum, nuclear factor-erythroid 2-like 2 in the jejunum, and heme oxygenase-1 in the duodenum and ileum; and the protein expression of ZO-1 and claudin in jejunum; however, it downregulated (p < 0.05) serum diamine oxidase activity and D-lactate level; small intestine mucosal malondialdehyde content; duodenum and ileum mucosal IL-6 level; jejunum mucosal TNF-α level; and the mRNA expression of IL-6 in the duodenum and jejunum, and TNF-α in the jejunum and ileum. These results suggested COS could maintain intestinal integrity under oxidative stress by modulating the intestinal oxidative status and release of inflammatory cytokines.

Efficacy of a phytonutrient supplement at different dietary protein contents on growth performance, gut morphology, digestive enzymes activities and stress indicators of broilers subjected to circular heat stress

Context Dietary manipulations such as reductions in protein or the addition of bioactive feed additives might alleviate the adverse effects of high ambient temperature in poultry. Aims The effects of dietary crude protein (CP) and phytonutrient mixture (PM) on growth performance and physiological responses were evaluated in broilers under circular heat stress (HS). Methods In total, 420 1-day-old broiler chickens were randomly distributed to seven treatments in a factorial arrangement (3 × 2), with three levels of CP (normal, medium (95% of the normal CP content) and low (90% of the normal CP content)) and with or without the addition of PM (mixture of 5 mg/kg carvacrol, 3 mg/kg cinnamaldehyde, and 2 mg/kg capsicum oleoresin). The thermoneutral control (TNC) birds were housed in a thermoneutral chamber and fed with a normal-CP diet without PM supplementation. The other six groups were kept in a HS chamber (33°C) for 8 h (1000 hours to 1800 hours). Key results After 6 weeks, feeding broiler chickens with low-CP diets had adversely affected growth performance and intestinal protease activities, while mortality rate, heterophile to lymphocyte ratio, and serum cortisol concentration of the low-CP group were lower (P &lt; 0.05) than those of the high-CP group. Dietary PM supplementation also positively influenced (P &lt; 0.05) average daily gain, feed conversion ratio, intestinal lipase and trypsin activities and serum T4 concentration. There were the CP × PM interactions (P &lt; 0.05) for jejunal villus height and villus surface area, indicating that the effect of PM on these responses was more marked at the lower dietary CP contents. Conclusions Supplementation with PM can ameliorate the detrimental effects of HS on productive performance and digestive enzyme activities in broilers. The PM supplementation could improve intestinal morphology when applied to the diets of heat-stressed broilers with lower CP contents (95% and 90% of the recommendations). Implications Although growth performance was reduced by feeding low-CP diets (90% of the normal CP content), a beneficial effect was observed on the stress indicators of broilers grown in HS conditions. Dietary supplementation of PM might also be an effective strategy to alleviate the adverse effect of HS.