Effect of dietary β-1,3-glucan supplementation and heat stress on growth performance, nutrient digestibility, meat quality, organ weight, ileum microbiota, and immunity in broilers

Effects of β-glucan on the performance and gut integrity of broilers under acute heat stress conditions

Heat stress (HS) has negative impacts on farm animals. Many studies have been conducted to ameliorate the effects of HS in farm animals. The current project investigated the effects of β-glucan (BG) supplementation under thermo-neutral and HS conditions on the production, physiological, and histological parameters in broiler chickens. Three-hundred and twenty chicks were randomly assigned into four treatments (10 replicates/treatment; 8 chicks/replicate). The treatments were: 1) a basal diet (Ctrl); 2) a diet containing 1 g/kg of β-glucan (BG1); 3) a diet containing 2 g/kg of β-glucan (BG2); 4) a diet containing 3 g/kg of β-glucan (BG3). All treatments were reared under thermo-neutral (TN) conditions from day 0-30 days of age then exposed to cyclical HS at the age of 31 days for 3 consecutive days (4 hours/day). During HS conditions, BG3 has increased feed intake (FI; 23 %; P < 0.01), and decreased rectal temperature (Tr) relative to the control treatment (0.5 °C; P <0.01). Besides, supplementing BG has improved average daily gain under HS conditions. In addition, BG supplementation had a positive effect on intestinal morphometric parameters (villous height, width, depth, and surface area) under HS conditions. In conclusion, feeding BG improved FI, average daily gain (ADG), and intestinal health in heat-stressed broiler chickens.

Effects of Algal-Derived β-Glucan on the Growth Performance, Intestinal Health, and Aeromonas veronii Resistance of Ricefield Eel (Monopterus albus)

Ricefield eel is an important economic fish in China. However, large-scale intensive breeding has increased the incidence of diseases in eels. In this study, we conducted an 8-week feeding trial to investigate the effects of β-glucan on the growth performance, intestinal health, and Aeromonas veronii resistance of Monopterus albus (M. albus). Three hundred healthy fish (initial body weight: 12.38 ± 0.50 g) were randomly divided into five groups: A1 (basal diet) was considered the control group, whereas A2, A3, A4, and A5 were the experimental groups. The fish in the experimental groups were fed a basal diet supplemented with 250, 500, 1000, and 2000 mg/kg β-glucan, respectively. The addition of 0.025%-0.2% β-glucan resulted in a notable enhancement of eel growth performance, with the most significant improvement observed in eels supplemented with 0.1% β-glucan (p < 0.05). Furthermore, 0.025%-0.2% β-glucan could significantly enhance the antioxidant properties of the eel intestinal tract (p < 0.05), and the addition of 0.1% β-glucan significantly improved trypsin (TPS), amylase (AMS), and lipase (LPS) activities in the intestine (p < 0.05). In terms of intestinal histology, the A3, A4, and A5 groups exhibited significantly greater villus height compared to the control group (p < 0.05). Concentrations of β-glucan at 0.1% and 0.2% enhanced the composition of the intestinal flora; specifically, the relative abundance of Proteobacteria increased, while the relative abundance of Firmicutes decreased. Moreover, the addition of 0.05%-0.2% β-glucan significantly improved the relative survival rate (SR) of A. veronii-infected eels and significantly decreased the bacterial load of the liver, spleen, and kidney (p < 0.05). In comparison to eels that did not receive β-glucan supplementation, eels supplemented with 0.2% β-glucan exhibited decreased intestinal structural damage. In summary, the addition of 0.1%-0.2% β-glucan can promote eel growth, improve intestinal digestion and antioxidant capacity, regulate intestinal flora, and enhance intestinal physical function and anti-infection ability.

Sprouted rough rice as an alternative to corn for growth, health performance and meat quality of broilers

Sprouted rough rice (SR) is not commly used for poultry diets but it could be a potential replacement ingredient to improve nutritional value of feed. This study aimed to evaluate the growth performance, carcass quality, blood lipids, hepatic enzymes, and fatty acid profiles of broiler meat when corn was replaced with sprouted rough rice in the feed. A completely randomized design was used with four groups and six replicate groups with 10 birds per replicate. The 4 treatment groups were 0, 15, 40 and 45 % sprouted-rice-replacement of corn. Growth performance and carcass quality were highest when corn was replaced with 45 % SR (p < 0.05). In particular, live weight and body weight gain increased linearly with increasing SR inclusion, whereas feed conversion ratio and feed intake linearly decreased with increasing SR (p < 0.05). Carcass, thigh, and breast weights showed the same trend of increase (p < 0.05). In addition, the pH of the thigh meat was significantly higher in diet with 45 % SR than in the other treatment groups. With increasing SR content, the weight of immune organs linearly increased, particularly the thymus and spleen (p < 0.05). Additionally, the fatty acids examined including saturated fatty acids, unsaturated fatty acid, transfat were mostly highest when 30 or 45 % of corn was replaced with SR and linearly increased from 0 to 45 % of SR. There were no significant differences of linear relationships with cooking loss, or blood lipid and hepatic enzyme profiles between treatments (p > 0.05). Replacing 45 % of corn in a broiler diet with SR could improve the growth and meat paramenters of broilers.

Impact of β-glucan dietary supplementation on productive, reproductive performance and physiological response of laying hens under heat stress conditions

The exploration for effective in-feed additives is growing owing to the global climatic change trend to alleviate the negative effects of heat stress in laying hens. This research assessed the potential of using B-glucan (G) as an antiheat stress agent in Matrouh laying hens subjected to early heat shock programs during the growing period. Factorial design (3 × 3) was used, including 3 levels of heat stress (control, heat shock at 3 d and at 3 d and 8 wk of age) and 3 levels of β-glucan (0, 100, and 200 mg β-glucan /kg diet). During the first 12 wk of egg production (EP), treatments were exposed to heat challenge. The results revealed that heat shock program applications at 3 d and 8 wk of age significantly decreased body weight at 36 wk of age (P < 0.05) and reduced (P < 0.05) feed intake (FI). While significantly (P < 0.05) improved feed conversion ratio (FCR), hemoglobin, RBCs, WBCs, immunoglobulin M (IgM), immunoglobulin G (IgG), and Heat shock protein (HSP70) of the Liver (P < 0.01) as compared with the control group. At the same time, there was a decrease in lymphocyte%, H/L ratio, cortisol, and T3 compared to the thermo-neutral control. When compared to the control group, hens fed a diet containing 200 mg of βG significantly (P < 0.05) improved body weight at 16 wk and final weight at 36 wk, feed conversion (FCR) (g. feed/g. egg mass), hen-day egg production, and egg mass, as well as the digestibility coefficients of crude protein (CP), dry matter (DM), metabolizable energy (ME), and cortisol. The interactions between heat chock programs and βG levels were nonsignificant for the most studied traits except daily feed intake. Therefore, the early heat shock exposure 2 times and supplementation of Β-glucan (βG) at 200 mg/kg diet during the growth period for laying hens that are exposed to heat stress during the reproductive period could improve productive, reproductive performance, HSP70 level and enhance immunity responses.

Effect of Cyberlindnera jadinii yeast on growth performance, nutrient digestibility, and gut health of broiler chickens from 1 to 34 d of age

The effect of dietary graded levels of Cyberlindnera jadinii yeast (C. jadinii) on growth performance, nutrient digestibility, and gut health of broilers was evaluated from 1 to 34 d of age. A total of 360 male broiler chicks were randomly allocated to 1 of 4 dietary treatments (6 replicate pens each) consisting of a wheat-soybean meal-based pelleted diet (Control or CJ0), and 3 diets in which 10% (CJ10), 20% (CJ20), and 30% (CJ30) of the crude protein were supplied by C. jadinii, by gradually replacing protein-rich ingredients. Body weight and feed intake were measured at d 1, 11, 22, and 32. Pellet temperature, durability, and hardness increased linearly (P < 0.05) with C. jadinii inclusion, with highest (P < 0.05) values for CJ30. Up until d 22, feed conversion ratio (FCR) was similar between treatments (P = 0.169). Overall, increasing C. jadinii inclusion linearly increased (P = 0.047) feed intake but had no effect on weight gain or mortality. FCR increased (P < 0.05) linearly with increasing C. jadinii inclusion but only birds fed CJ30 had a significantly poorer FCR compared to the Control. Ileal digestibility was not affected by C. jadinii inclusion, however, there was a significant linear decrease in crude protein and phosphorus, and a tendency for a decrease in fat digestibility. Apparent metabolizable energy (AME) decreased (P < 0.001) quadratically with increasing C. jadinii and was significantly lower in CJ30 compared to the Control. Ileal concentrations of volatile fatty acids (VFAs) were not affected by C. jadinii inclusion, but butyric acid and total VFAs were linearly and quadratically increased and were significantly higher in cecal digesta of birds fed CJ20 and CJ30. Increasing C. jadinii inclusion was associated with an increase (P < 0.05) in the relative abundance of lactobacillus in the ileum and cecum. In conclusion, C. jadinii yeast can supply up to 20% of the total dietary protein without negatively affecting performance, digestibility, or gut health of broilers. The potential confounding role of feed processing and C. jadinii cell wall components on broiler performance is discussed.

Biogenic Selenium Nanoparticles Synthesized Using Alginate Oligosaccharides Attenuate Heat Stress-Induced Impairment of Breast Meat Quality via Regulating Oxidative Stress, Metabolome and Ferroptosis in Broilers

Selenium (Se) is an indispensable trace element with versatile functions in antioxidant defense in poultry. In our previous study, we synthesized a novel type of biogenic selenium nanoparticle based on alginate oligosaccharides (SeNPs-AOS), and found that the particles are sized around 80 nm with an 8% Se content, and the dietary addition of 5 mg/kg of SeNPs-AOS could effectively alleviate the deleterious effects of heat stress (HS) in broilers, but it is still unclear whether SeNPs-AOS can improve the meat quality. Therefore, the aim of this study was to evaluate the protective effects of SeNPs-AOS on breast meat quality in heat-stressed broilers, and explore the relevant mechanisms. Birds at the age of 21 days were randomly divided into four groups with six replicates per group (eight broilers per replicate) according to a 2 × 2 experimental design, using HS (33 ± 2 °C, 10 h/day vs. thermoneutral, TN, under 23 ± 1.5 °C) and SeNPs-AOS (5 mg/kg feed vs. no inclusion) as variables. The results showed that dietary SeNPs-AOS decreased the cooking loss (p < 0.05), freezing loss (p < 0.001), and shear force (p < 0.01) of breast muscle in heat-stressed broilers. The non-targeted metabolomics analysis of the breast muscle identified 78 differential metabolites between the HS and HS + SeNPs-AOS groups, mainly enriched in the arginine and proline metabolism, β-alanine metabolism, D-arginine and D-ornithine metabolism, pantothenate, and CoA biosynthesis pathways (p < 0.05). Meanwhile, supplementation with SeNPs-AOS increased the levels of the total antioxidant capacity (T-AOC), the activities of catalase (CAT) and glutathione peroxidase (GSH-Px), and decreased the content of malondialdehyde (MDA) in the breast muscle (p < 0.05) in broilers under HS exposure. Additionally, SeNPs-AOS upregulated the mRNA expression of CAT, GPX1, GPX3, heme oxygenase-1 (HO-1), masculoaponeurotic fibrosarcoma G (MafG), MafK, selenoprotein W (SELENOW), SELENOK, ferritin heavy polypeptide-1 (FTH1), Ferroportin 1 (Fpn1), and nuclear factor erythroid 2-related factor 2 (Nrf2) (p < 0.05), while it downregulated Kelch-like ECH-associated pro-36 tein 1 (Keap1) and prostaglandin-endoperoxide Synthase 2 (PTGS2) expression (p < 0.05) in broilers under HS. These findings demonstrated that the dietary addition of SeNPs-AOS mitigated HS-induced oxidative damage and metabolite changes in the breast muscle of broilers, which may be related to the regulation of the Nrf2 signaling pathway and selenoprotein synthesis. In addition, SeNPs-AOS upregulated the breast muscle gene expression of anti-ferroptosis-related molecules in broilers under HS, suggesting that SeNPs-AOS can be used as novel Se supplements against HS in broilers.

Applications of Enteroendocrine Cells (EECs) Hormone: Applicability on Feed Intake and Nutrient Absorption in Chickens

This review focuses on the role of hormones derived from enteroendocrine cells (EECs) on appetite and nutrient absorption in chickens. In response to nutrient intake, EECs release hormones that act on many organs and body systems, including the brain, gallbladder, and pancreas. Gut hormones released from EECs play a critical role in the regulation of feed intake and the absorption of nutrients such as glucose, protein, and fat following feed ingestion. We could hypothesize that EECs are essential for the regulation of appetite and nutrient absorption because the malfunction of EECs causes severe diarrhea and digestion problems. The importance of EEC hormones has been recognized, and many studies have been carried out to elucidate their mechanisms for many years in other species. However, there is a lack of research on the regulation of appetite and nutrient absorption by EEC hormones in chickens. This review suggests the potential significance of EEC hormones on growth and health in chickens under stress conditions induced by diseases and high temperature, etc., by providing in-depth knowledge of EEC hormones and mechanisms on how these hormones regulate appetite and nutrient absorption in other species.

Effects of dietary β-glucan and rice fermented on growth performance, fatty acids, and Newcastle disease immune response in turkey broilers

Poultry production has been developing in Vietnam with challenges of disease. Thus, feed additive should be investigated not only growth but also health enhancement. Here, we aimed to determine the effects of Saccharomyces cerevisiae-fermented rice (FR) and β-glucan on turkey's growth performance, carcass characteristics, immune and fatty acid (FA) profiles. A total of 180 turkey chicks aged 1-56 days were randomly assigned to five sextuplicate groups and the birds had ad libitum feed and water access throughout the experiment. The five treatment groups were given the same diet with different proportions of FR and β-glucan. Broilers supplemented with 4% β-glucan and 4% FR presented the highest and second-highest growth performance, respectively. The 4% β-glucan and 4% FR treatments resulted in the highest carcass characteristic values without significantly affecting the breast or thigh meat pH or cooking loss. The 4% β-glucan and 4% FR treatments maximally increased the Newcastle disease (ND) antibody titers at 28, 42 and 56 days, respectively as well as thymus organ index. The foregoing treatments did not significantly affect the blood profiles relative to the control. However, the 4% FR treatment lowered the blood cholesterol levels (p > 0.05). The total FA profiles did not significantly differ among treatments. Nevertheless, both the β-glucan and FR treatments increased the MUFA levels compared to that of the control (p > 0.05). Hence, the dietary administration of 4% β-glucan and FR to turkey broilers could effectively improve their growth performance and immunity.

Dietary 1,3-β-Glucans Affect Growth, Breast Muscle Composition, Antioxidant Activity, Inflammatory Response, and Economic Efficiency in Broiler Chickens

Recently, researchers have been intensively looking for novel, safe antibiotic alternatives because of the prevalence of many clinical and subclinical diseases affecting bird flocks and the risks of using antibiotics in subtherapeutic doses as feed additives. The present study intended to evaluate the potential use of 1,3-β-glucans (GLC) as antibiotic alternative growth promotors and assessed the effect of their dietary inclusion on the growth performance, carcass traits, chemical composition of breast muscles, economic efficiency, blood biochemical parameters, liver histopathology, antioxidant activity, and the proinflammatory response of broiler chickens. This study used 200 three-day-old ROSS broiler chickens (50 chicks/group, 10 chicks/replicate, with an average body weight of 98.71 ± 0.17 g/chick). They were assigned to four experimental groups with four dietary levels of GLC, namely 0, 50, 100, and 150 mg kg−1, for a 35-day feeding period. Birds fed diets containing GLC showed an identical different growth rate to the control group. However, the total feed intake (TFI) increased quadratically in the GLC50 and GLC100 groups as compared to that in the control group. GLC addition had no significant effect on the weights of internal and immune organs, except for a decrease in bursal weight in the GLC150 group (p = 0.01). Dietary GLC addition increased the feed cost and total cost at 50 and 100 mg kg−1 doses. The percentages of n-3 and n-6 PUFA in the breast muscle of broiler chickens fed GLC-supplemented diets increased linearly in a dose-dependent manner (p < 0.01). The serum alanine aminotransferase (ALT) level and the uric acid level were quadratically increased in the GLC150 group. The serum levels of total antioxidant capacity, catalase, superoxide dismutase, interleukin-1β, and interferon-gamma linearly increased, while the MDA level decreased in the GLC-fed groups in a dose-dependent manner. Normal histological characterization of different liver structures in the different groups with moderate round cells was noted as a natural immune response around the hepatic portal area. The different experimental groups showed an average percentage of positive immunostaining to the proinflammatory marker transforming growth factor-beta with an increase in the dose of GLC addition. The results suggest that GLC up to 100 mg kg−1 concentration can be used as a feed additive in the diets of broiler chickens and shows no adverse effects on their growth, dressing percentage, and internal organs. GLC addition in diets improves the antioxidant activity and immune response in birds. GLC help enrich the breast muscle with n-3 and n-6 polyunsaturated fatty acids.

Effects of dietary β-1,3-glucan addition on the growth performance, mRNA expression in jejunal barrier, and cecal microflora of broilers challenged with Clostridium perfringens

This experiment aimed to explore the interaction of β-1,3-glucan and Clostridium perfringens on the growth performance, intestinal health and cecal microflora of broilers. A total of 384 one-day-old Arbor Acre broilers were sorted into 4 treatments with 6 replications. There were 2 factors in this trial: dietary β-1,3-glucan addition including 0 and 250 mg/kg, intestinal enteritis challenged with Clostridium perfringens attack or not. Results showed that Clostridium perfringens infection disrupted the integrity of the intestinal mucosa by reducing the jejunal Occludin and Claudin-1 mRNA expression of broiler chickens at 21 d of age (P < 0.05). Meanwhile, when considering Clostridium perfringens as the main effect, it also decreased the mRNA expression of the glucose transporter recombinant sodium/glucose cotransporter 1 (SGLT1) at d 21 and the fatty acid transporter liver fatty acid-binding protein (L-FABP) at d 42 (P < 0.05) as well as affect cecum microbial diversity, especially in relative abundance of Firmicutes and Bacteroidetes. In addition, Clostridium perfringens infection reduced body weight, daily weight gain, and feed-gain ratio (FCR) in broilers at d 42 (P < 0.05). The dietary β-1,3-glucan could alleviate intestinal mucosal damage caused by the Clostridium perfringens to some extent. When considering β-1,3-glucan as the main effect, it increased the SGLT1 at 42 d of age (P < 0.05), and stabilized gut microbiota disorder caused by Clostridium perfringens. More over dietary β-1,3-glucan addition increased body weight at 42-day-old (P < 0.05), and improved daily weight gain and FCR during 1 to 42 d (P < 0.05). In conclusion, dietary β-1,3-glucan could improve growth performance and intestinal health in broilers infected with Clostridium perfringens.

Effect of 1,3-Beta Glucans Dietary Addition on the Growth, Intestinal Histology, Blood Biochemical Parameters, Immune Response, and Immune Expression of CD3 and CD20 in Broiler Chickens

This experiment evaluated the impact of the dietary addition of 1,3-β-glucans (GLU) on broiler chickens’ growth, intestinal histology, blood biochemical parameters, and immunity. Two hundred three-day-old male broilers (Ross 308) (97.93 ± 0.19 g/chick) were randomly assigned into four treatments with five replicates, each containing ten birds, in a complete randomized design. The four treatments were formulated with 0, 50, 100, and 150 mg 1,3-β-glucans kg−1 in broiler chicken diets. During the study, no significant impacts (p > 0.05) were observed in weight gain and feed conversion ratio (FCR) between treatment groups. Based on the results of total body weight gain and FCR, the optimal level of 1,3-β-glucan is 120 mg Kg−1. The intestinal histomorphology was improved by GLU supplementation, as indicated by increased villi height and villi height to crypt depth ratio (p < 0.01). All levels of supplemental β-1,3 glucan decreased the serum total cholesterol (TC), triglyceride levels, and low-density lipoprotein cholesterol (LDL-C) (p < 0.05). The serum levels of growth hormones (GH), triiodothyronine (T3), and thyroxine (T4) were increased in GLU-supplemented groups (p < 0.05). The serum immune indices (lysozyme activity, interleukin 10 (IL10), complement 3 (C3), and total protein levels) were increased in the GLU-supplemented groups (p < 0.05). Dietary GLU up-regulated the immunoexpression of CD3 (T-cell marker) and CD20 (B-cell marker) in the spleen of birds (p < 0.01). It can be concluded that 1,3-β-glucan can be added to broiler chicken diets for improving the development and integrity of the intestine and enhancing the bird’s immune status. The optimal level for 1,3-β-glucan dietary supplementation was 120 mg Kg−1. Dietary 1,3-β-glucan has a hypolipidemic effect and improves the hormonal profile of birds without affecting their growth rate.

Heat stress-induced intestinal barrier damage and dimethylglycine alleviates via improving the metabolism function of microbiota gut brain axis

Heat stress, a widely occurred in subtropical climate regions, causes ecosystem destruction, and intestine injury in humans and animals. As an important compound in the metabolic pathway of choline, dimethylglycine (DMG) shows anti-inflammatory effects. This study examines the beneficial effects of dietary DMG against heat stress-induced intestine injury and further explores the underlying molecular mechanisms using a broiler model. Here, we showed that DMG supplements exhibited positive effects to growth performance, as evidenced by the significantly increased body weight and feed conversion rate. These therapeutic effects attributed to repaired gut barrier integrity, increased content of anti-inflammatory cytokines IL-10, decreased content of pro-inflammatory cytokines IL-6, and down-regulated gene expression of the NF-κB signaling pathway. DMG treatment led to the reshaping of the gut microbiota composition, mainly increasing the short-chain fatty acid (SCFAs) strains such as Faecalibacterium, and Marvinbryantia. DMG treatment also increased two main members of SCFAs, including acetate acid and isobutyrate. Particularly, distinct effects were found which mediated the tryptophan metabolism in intestines such as increased tryptophan and 5-HT, which further alleviate the occurrence of intestinal barrier damage caused by heat stress. Additionally, DMG treatment promoted neuroendocrine function and stimulated the hypothalamic neurotransmitter metabolism by activating tryptophan metabolism in the hypothalamus. Overall, DMG supplementation effectively reduced the occurrence of intestinal inflammation induced by heat stress through modulating cecal microbial communities and improving the metabolism function of microbiota gut brain axis. Our findings revealed a novel mechanism by which gut microbiota could improve host health.

Effects of Dietary Yeast β-Glucan Supplementation on Meat Quality, Antioxidant Capacity and Gut Microbiota of Finishing Pigs

Yeast β-glucan is a natural antioxidant and has been reported to improve growth performance of piglets, but its application in improving pork quality is limited. This study investigated the effects of dietary yeast β-glucan supplementation on meat quality, antioxidant capacity and gut microbiota of finishing pigs. In a 40-day experiment, ninety finishing pigs (Duroc × Landrace × Yorkshire, 70.47 ± 0.04 kg) were randomly allocated into five treatments including a basal diet supplemented with 0, 50, 100, 200 and 400 mg/kg yeast β-glucan. Results showed that yeast β-glucan significantly increased pH45 min (linear and quadratic, p < 0.01) and a*45 min (linear, p < 0.05), and reduced cooking loss (linear, p < 0.05) and drip loss (quadratic, p < 0.05) of meat in finishing pigs. Importantly, the 200 mg/kg group exhibited the highest values of pH45 min (p < 0.01) and the lowest values of drip loss (p < 0.05), accompanied by a decreased lactate content (p < 0.05) and glycolytic potential (p < 0.05). Dietary supplementation of 200 mg/kg yeast β-glucan markedly increased catalase (CAT) (p < 0.05), superoxide dismutase (SOD) (p < 0.05) and total antioxidant capacity (T-AOC) (p < 0.01) activities in skeletal muscle. Moreover, WPS-2 abundance was decreased significantly in colonic digesta by 200 mg/kg yeast β-glucan and exhibited a positive association with muscle lactate content and drip loss. Together, dietary 200 mg/kg yeast β-glucan supplementation effectively improved pH value and the water-holding capacity of fresh meat through reducing muscle postmortem glycolysis, increasing antioxidant capacity and altering the gut microbiota composition of finishing pigs.

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.

Ileal Microbiota Alters the Immunity Statues to Affect Body Weight in Muscovy Ducks

The ileum is mainly responsible for food absorption and nutrients transportation. The microbes in its intestinal lumen play an essential role in the growth and health of the host. However, it is still unknown how the ileal microbes affect the body weight of the host. In this study, we used Muscovy ducks as an animal model to investigate the relationship between the ileal microbes and body weight and further explore the potential mechanism. The ileum tissue and ileal contents of 200 Muscovy ducks were collected for mRNA extraction and real-time quantitative PCR, as well as DNA separation and 16S rRNA gene sequencing. With body weight being ranked, the bottom 20% (n = 40) and top 20% (n = 40) were set as the low and high groups, respectively. Our results showed that in the ileum of Muscovy ducks, the Bacteroides, Firmicutes, and Proteobacteria were the predominant phyla with the 10 most abundant genera, namely Candidatus Arthromitus, Bacteroides, Streptococcus, Vibrio, Romboutsia, Cetobacterium, Clostridium sensu stricto 1, Terrisporobacter, Escherichia-Shigella, and Lactobacillus. We identified Streptococcus, Escherichia-Shigella, Candidatus Arthromitus, Bacteroides, Faecalibacterium, and Oscillospira were closely correlated to the growth of Muscovy ducks. Streptococcus and Escherichia-Shigella were negatively related to body weight (BW), while Candidatus Arthromitus, Bacteroides, Faecalibacterium, and Oscillospira were positively associated with BW. In addition, we found that the relative expression levels of tight junction proteins (Claudin 1, Claudin 2, ZO-1 and ZO-2) in the high group showed an upward trend, although this trend was not significant (P > 0.05). The expression of pro-inflammatory factors (IL-1β, IL-2 and TNF-α) decreased in the high group, while the anti-inflammatory factor IL-10 increased. Of course, except IL-2, these differences were not significant (P > 0.05). Finally, the correlation analysis showed that Escherichia-Shigella was significantly positively correlated with IL-1β (P < 0.05). These findings may provide fundamental data for the development of next-generation probiotics and assist the development of strategies for changing the gut microbiota to promote the growth performance in the duck industry.

Effects of a direct fed microbial (DFM) on broiler chickens exposed to acute and chronic cyclic heat stress in two consecutive experiments

Two consecutive 35 d experiments were conducted to investigate the effects of a multistrain DFM fed continuously to broiler chickens exposed to HS from 28 to 35 d on broiler performance, body composition, ileal digestibility, and intestinal permeability using serum Fluorescein Isothiocyanate Dextran (FITC-d) concentration. The treatments were arranged as a 2 × 2 factorial with temperature: Elevated (HS: 33 ± 2°C for 6 h and 27.7°C for the remaining 18 h from 28 to 35 days of age) and Thermoneutral (TN: 22 to 24°C over the entire 24-h day from 28 to 35 days of age) and diet: corn-soybean meal based with and without DFM (3-strain Bacillus; Enviva PRO) fed over the entire 35-d period as the two factors. Experimental diets were formulated to meet all nutrient recommendations based on breed standards using a starter (0–10 d), grower (10–21 d), and finisher (21–35 d) period. For each of the 2 experiments, 648 Ross 708 broiler chicks were allotted among the treatments with 9 replicate pens of 18 broilers. Data were analyzed as a 2 × 2 factorial within each experiment in JMP 14. In both experiments, cloacal temperatures were increased (P ≤ 0.05) in the broilers subjected to the HS treatment at both 28 d (acute) and 35 d (chronic). Supplementing birds with DFM reduced cloacal temperatures in the Experiment 1 at 28 d, but not at the other time periods. The HS treatment reduced body weight gain and lean tissue accretion from 0 to 35 d in both experiments (P ≤ 0.05). In Experiment 2, when the litter was reused BWG was increased by 36 g/bird with supplementation of DFM (P ≤ 0.05). Ileal digestibility at 28 d (2 h post HS) was improved with DFM supplementation in both experiments (P ≤ 0.05). Serum FITC-d increased with HS at both 28 and 35 d. Serum FITC-d was generally decreased with DFM at 28 d but the response was inconsistent at 35 d. Overall, the results suggest that HS reduced broiler performance and DFM treatment improved intestinal permeability and nutrient digestibility responses to HS in both experiments but did not improve performance until built up litter was used in Experiment 2.

Plant-Derived Polysaccharides Regulated Immune Status, Gut Health and Microbiota of Broilers: A Review

In modern intensive breeding system, broilers are exposed to various challenges, such as diet changes and pathological environment, which may cause the increase in the incidence rate and even death. It is necessary to take measures to prevent diseases and maintain optimal health and productivity of broilers. With the forbidden use of antibiotics in animal feed, polysaccharides from plants have attracted much attention owing to their lower toxicity, lower drug resistance, fewer side effects, and broad-spectrum antibacterial activity. It had been demonstrated that polysaccharides derived from plant exerted various functions, such as growth promotion, anti-inflammation, maintaining the integrity of intestinal mucosa, and regulation of intestinal microbiota. Therefore, the current review aimed to provide an overview of the recent advances in the impacts of plant-derived polysaccharides on anti-inflammation, gut health, and intestinal microbiota community of broilers in order to provide a reference for further study on maintaining the integrity of intestinal structure and function, and the related mechanism involved in the polysaccharide administration intervention.

β-glucan modulates non-specific immune gene expression, thermal tolerance and elicits disease resistance in endangered Tor putitora fry challenged with Aeromonas salmonicida

An eight-week feeding trial was performed to assess the effect of different dietary levels (0, 0.5, 1.0, and 1.5%) of β-glucan (sourced from Saccharomyces cerevisiae) on growth, survival, immunological parameters (immune gene expression, lysozyme, and antiprotease), total antioxidant status, thermal tolerance, and disease resistance of Tor putitora fry. Feeding of moderate doses (0.5 and 1.0%) of β-glucan significantly improved survival but not weight gain percentage as compared to that received unsupplemented control and highest dose (1.5%) of glucan. Supplementation of β-glucan in diets differentially influenced the mRNA expression of cytokine and other immune genes. For instance, transcripts of cytokines such as tnf-α and il-1β were significantly upregulated, while ifn-γ and il-10 were unaffected by β-glucan intake. Also, the relative mRNA expression of tlr-5 and hepcidin1 along with lysozyme and antiprotease activities were remained largely unchanged by dietary glucan administration. In contrast, β-glucan induced mRNA expression of defensin1 and c3 while decreased the transcript level of mhc-1. On the other hand, dietary inclusion of β-glucan markedly improved total antioxidant levels and extended the thermal tolerance limits at both the ends, as shown by increased CT_max and lower CT_min than the control group. After feeding β-glucan for eight weeks, the fish were bath challenged with a bacterial pathogen, Aeromonas salmonicida. The challenge study results revealed that β-glucan intake improved most of the studied immune parameters, resulting in lower mortality. Overall, dietary inclusion of β-glucan (0.5-1.0%) was efficient in improving the immune responses, thermal tolerance, and disease resistance of T. putitora fry.

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.

Citrullus colocynthis Seeds: A Potential Natural Immune Modulator Source for Broiler Reared under Chronic Heat Stress

Simple Summary

Chronic heat-stress exposure directly affects broiler immune response. Immunosuppression was demonstrated in broiler exposed to chronic heat stress with deterioration in humoral and cell-mediated immune responses. Natural immune modulator material is considered as a safe material for human consumption of poultry products. Citrullus colocynthis (CC) is a natural herb plant that has traditionally been used in folk remediation. Anti-diabetic, antioxidant, and anti-inflammatory attributes are some of the CC medical properties. The present study aims to investigate the immune modulator potentials of CC seeds supplementation to chronically heat- stressed-exposed broilers. Results demonstrated that CC seeds supplementation to heat-stressed broilers was able to alleviate the negative impacts of heat stress on broiler immune responses and antioxidant status. Thus, CC seeds are suggested to be added to broilers reared under heat stress in order to improve the immune response and consequently ameliorate productivity.

Abstract

There is an extensive search for natural products that can be introduced to broiler rations to improve performance, especially during the unfavorable breeding conditions. Under heat-stress conditions, the immune response seriously deteriorates, which consequently impairs broiler production performance. Thus, the present study aimed to investigate the potentials of Citrullus colocynthis seeds (CCs) supplementation to modulate the immune response of broilers subjected to chronic heat stress. A total of 300 Cobb-500 male broiler chickens aged 21 days were randomly divided into two equal groups and reared under either thermo-neutral condition (24 ± 1 °C) or subjected to cyclic heat stress (34 ± 1 °C for 8 h). Each group was further divided into two groups (5 replicate × 15 chicks) and was fed either the basal diet or the basal diet with 0.1% CCs supplementation. The results showed that heat stress impaired the production performance by lowering the final body weight and feed intake as well as impairing feed conversion. The levels of stress markers (i.e., malondialdehyde, tumor necrosis factor-α and corticosterone) increased (p < 0.05), whereas the activity of antioxidant enzymes decreased in broilers exposed to heat stress. Further, heat stress caused direct suppression of broiler humoral and cell-mediated immune responses. The stimulating index of T and B lymphocytes proliferation, as well as the antibody titer against sheep red blood cells, were significantly (p < 0.05) reduced by heat-stress exposure. However, CCs supplementation to broilers subjected to heat stress improved (p < 0.05) the final body weight, feed intake, and feed conversion ratio (FCR), compared to the non-supplemented stressed group. The cellular and cell-mediated immune response indicators significantly enhanced (p < 0.05) with CCs supplementation. Supplementation of CCs to broilers reared under similar environmental conditions elevated the total white blood cells (TWBCs) count and the broiler stimulating index of T and B lymphocytes. It can be concluded that CC seeds can be effectively used to stimulate the immune response and improve the production performance of broilers reared under heat-stress condition.

Review: β-glucans as Effective Antibiotic Alternatives in Poultry

The occurrence of microbial challenges in commercial poultry farming causes significant economic losses. Antibiotics have been used to control diseases involving bacterial infection in poultry. As the incidence of antibiotic resistance turns out to be a serious problem, there is increased pressure on producers to reduce antibiotic use. With the reduced availability of antibiotics, poultry producers are looking for feed additives to stimulate the immune system of the chicken to resist microbial infection. Some β-glucans have been shown to improve gut health, to increase the flow of new immunocytes, increase macrophage function, stimulate phagocytosis, affect intestinal morphology, enhance goblet cell number and mucin-2 production, induce the increased expression of intestinal tight-junctions, and function as effective anti-inflammatory immunomodulators in poultry. As a result, β-glucans may provide a new tool for producers trying to reduce or eliminate the use of antibiotics in fowl diets. The specific activity of each β-glucan subtype still needs to be investigated. Upon knowledge, optimal β-glucan mixtures may be implemented in order to obtain optimal growth performance, exert anti-inflammatory and immunomodulatory activity, and optimized intestinal morphology and histology responses in poultry. This review provides an extensive overview of the current use of β glucans as additives and putative use as antibiotic alternative in poultry.