Effects of Lactobacillus salivarius supplementation on the growth performance, liver function, meat quality, immune responses and Salmonella Pullorum infection resistance of broilers challenged with Aflatoxin B1

The mitigative role of novel aflatoxin-degrading enzymes in diverse broiler performance indicators and gut microbiota following the consumption of diets contaminated with aflatoxins

BACKGROUND

This study aims to explore both the toxic effects of aflatoxins (AFs) and the protective effects of degrading enzymes (DE) on broilers exposed to AFs.

RESULTS

The findings reveal that a diet contaminated with 69.15 μg kg-1 of aflatoxin B1 had significant adverse effects on broilers. Specifically, it led to a reduction in average daily gain, dressed yield percentage, half-eviscerated yield with giblet yield percentage, eviscerated yield percentage, as well as serum superoxide dismutase (SOD), glutathione peroxidase activity and liver SOD activity (P < 0.05). Conversely, the diet increased the feed conversion ratio, liver index, serum glutamic oxaloacetic transaminase levels and malondialdehyde levels in both serum and liver (P < 0.05). Additionally, AFs disrupted the intestinal microflora significantly (P < 0.05), altering the relative abundance of Enterococcus, Lactobacillus and Escherichia in broiler jejunum. The addition of DE to AF-contaminated feed mitigated these negative effects and reduced the residues of aflatoxin B1, aflatoxin B2 and aflatoxin M1 in the liver and duodenum (P < 0.05). We also observed that broilers fed the diet pelleted at 80 °C exhibited improved dressing percentage and water holding capacity compared to those on the 75 °C diet.

CONCLUSION

In summary, DE serves as an effective feed additive for mitigating AF contamination in poultry production. © 2024 Society of Chemical Industry.

Aflatoxin B1-induced liver pyroptosis is mediated by disturbing the gut microbial metabolites: The roles of pipecolic acid and norepinephrine

The disturbed gut microbiota is a key factor in activating the aflatoxin B1 (AFB1)-induced liver pyroptosis by promoting inflammatory hepatic injury; however, the pathogen associated molecular pattern (PAMP) from disturbed gut microbiota and its mechanism in activating liver pyroptosis remain undefined. By transplanting AFB1-originated fecal microbiota and sterile fecal microbial metabolites filtrate, we determined the association of PAMP in AFB1-induced liver pyroptosis. Notably, AFB1-originated sterile fecal microbial metabolites filtrate were more active in triggering liver pyroptosis in mice, as compared to parental fecal microbiota. This result supported a critical role of the metabolic homeostasis of gut microbiota in AFB1-induced liver pyroptosis, rather than an injurious response to direct exposure of AFB1 in liver. Among the gut-microbial metabolites, pipecolic acid and norepinephrine were proposed to bind TLR4 and NLRP3, the upstream proteins of pyroptosis signaling pathway. Besides, the activations of TLR4 and NLRP3 were linearly correlated with the concentrations of pipecolic acid and norepinephrine in the serum of mice. In silenced expression of TLR4 and NLRP3 in HepG2 cells, pipecolic acid or norepinephrine did not able to activate hepatocyte pyroptosis. These results demonstrated the necessity of gut microbial metabolism in sustaining liver homeostasis, as well as the potential to provide new insights into targeted intervention for AFB1 hepatotoxicity.

The protective effects of Lactobacillus SNK-6 on growth, organ health, and intestinal function in geese exposed to low concentration Aflatoxin B1

Aflatoxin B1 (AFB1) is a prevalent mycotoxin present in feed ingredients. In this study, we investigated the effects of Lactobacillus salivarius (L. salivarius) on the Landes geese exposed to AFB1. The 300 one-day-old Landes geese were randomly divided into five groups: The control group received a basic diet, while the other groups were fed a basic diet supplemented with 10 μg/kg AFB1, 10 μg/kg AFB1+ 4*108 cfu/g L. salivarius, 50 μg/kg AFB1, and 50 μg/kg AFB1 + 4*108 cfu/g L. salivarius for 63 d. Results showed that high level AFB1 exposure significantly decreased final BW and ADG, increased feed/gain ratio (F/G) and liver index (P < 0.05). L. salivarius improved levels of IL-1, IL-6, and IL-12 under low level of AFB1 exposure (P < 0.05), along with similar trends observed in serum IgA, IgG, IgM, T3, T4, TNF-ɑ, and EDT (P < 0.05). AFB1 exposure reduced jejunum villus high and villus high/crypt depth ratio, and suppressed expression of ZO-1, Occludin, and Claudin-1 mRNA, and significant improved with L. salivarius supplementation under low level AFB1 exposure (P < 0.05). AFB1 significantly increased expression levels of TLR3 and NF-kB1, with supplementation of L. salivarius showing significant improvement under low AFB1 exposure (P < 0.05). Cecal microbiota sequencing revealed that under low level AFB1 exposure, supplementation with L. salivarius increased the abundance of Bacteroidetes and Lactococcus. In summary, supplementation with 4*108 cfu/g L. salivarius under 10 μg/kg AFB1 exposure improved growth performance and immune capacity, enhanced jejunum morphology, reduced liver inflammation, altered the cecal microbial structure, and positively affected the growth and development of geese.

Lactobacillus salivarius Ameliorates AFB1-induced hepatotoxicity via PINK1/Parkin-mediated mitophagy in Geese

Aflatoxin B1 (AFB1) is commonly found in feed ingredients and foods all over the world, posing a significant threat to food safety and public health in animals and humans. Lactobacillus salivarius (L. salivarius) was recorded to improve the intestinal health and performance of chickens. However, whether L. salivarius can alleviate AFB1-induced hepatotoxicity in geese was unknown. A total of 300 Lande geese were randomly assigned to five groups: control group, AFB1 low-dose group (L), L. salivarius+AFB1 low-dose group (LL), AFB1 high dosage groups (H), L. salivarius+AFB1 high dosage groups (LH), respectively. The results showed that the concentrations of ALT, AST, and GGT significantly increased after exposure to AFB1. Similarly, severe damage of hepatic morphology was observed including the hepatic structure injury and inflammatory cell infiltration. The oxidative stress was evidenced by the elevated concentrations of MDA, and decreased activities of GSH-Px, GSH and SOD. The observation of immunofluorescence, real-time PCR, and western blotting showed that the expression of PINK1 and the value of LC3II/LC3I were increased, but that of p62 significantly decreased after AFB1 exposure. Moreover, the supplementation of L. salivarius effectively improved the geese performance, ameliorated AFB1-induced oxidative stress, inhibited mitochondrial mitophagy and enhanced the liver restoration to normal level. The present study demonstrated that L. salivarius ameliorated AFB1-induced the hepatotoxicity by decreasing the oxidative stress, and regulating the expression of PINK1/Parkin-mediated mitophagy in the mitochondria of the geese liver. Furthermore, this investigation suggested that L. salivarius might serve as a novel and safe additive for preventing AFB1 contamination in poultry feed.

A sandwich-type photoelectrochemical biosensor based on Ru(bpy)32+ sensitized In2S3 for aflatoxin B1 detection

Aflatoxin B1 (AFB1), classified as a class I carcinogen, is a widespread mycotoxin that poses a serious threat to public health and economic development, and the food safety problems caused by AFB1 have aroused worldwide concern. The development of accurate and sensitive methods for the detection of AFB1 is significant for food safety monitoring. In this work, a sandwich-type photoelectrochemical (PEC) biosensor for AFB1 detection was constructed on the basis of an aptamer-antibody structure. A good photocurrent response was obtained due to the sensitization of In2S3 by Ru(bpy)32+. In addition, this sandwich-type sensor constructed by modification with the antibody, target detector, and aptamer layer by layer attenuated the migration hindering effect of photogenerated carriers caused by the double antibody structure. The aptamer and antibody synergistically recognized and captured the target analyte, resulting in more reliable PEC response signals. CdSe@CdS QDs-Apt were modified as a signal-off probe onto the sensor platform to quantitatively detect AFB1 with a "signal-off" response, which enhanced the sensitivity of the sensor. The PEC biosensor showed a linear response range from 10-12 to 10-6 g mL-1 with a detection limit of 0.023 pg mL-1, providing a feasible approach for the quantitative detection of AFB1 in food samples.

Aflatoxin B1 exposure exacerbates chemokine receptor expression in the BTBR T+ Itpr3tf/J Mouse Model, unveiling insights into autism spectrum disorder: A focus on brain and spleen

OBJECTIVE

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by significant difficulties in social interaction, communication, and repeated stereotypic behaviour. Aflatoxin B1 (AFB1) is the most potent and well-known mycotoxin in various food sources. Despite its propensity to generate significant biochemical and structural changes in human and animal tissues, the influence of AFB1 on ASD has yet to be thoroughly studied. Mounting evidence indicates that chemokine receptors play a crucial function in the central nervous system and are implicated in developing several neuroinflammatory disorders. Chemokine receptors in individuals with ASD were elevated in the anterior cingulate gyrus astrocytes, cerebellum, and brain.

METHODS

The BTBR T+Itpr3tf/J (BTBR) mice are inbred strains that exhibit strong and consistently observed deficits in social interactions, characterized by excessive self-grooming and limited vocalization in social contexts. We examined the impact of AFB1 on CCR3-, CCR7-, CCR9-, CXCR3-, CXCR4-, and CXCR6-expressing I-A/I-E+ cells in the spleen of the BTBR mouse model of autism. We evaluated the mRNA levels of CCR3, CCR7, CCR9, CXCR3, CXCR4, and CXCR6 chemokine receptors in the brain.

RESULTS

The exposure to AFB1 in BTBR mice resulted in a significant rise in the number of I-A/I-E+CCR3+, I-A/I-E+CCR7+, I-A/I-E+CCR9+, I-A/I-E+CXCR3+, I-A/I-E+CXCR4+, and I-A/I-E+CXCR6+ cells. Furthermore, exposure to AFB1 increased mRNA expression levels of CCR3, CCR7, CCR9, CXCR3, CXCR4, and CXCR6 in the brain.

CONCLUSIONS

These findings highlight that AFB1 exposure increases the expression of chemokine receptors in BTBR mice, indicating the necessity for further research into AFB1's role in the development of ASD.

Gallnut tannic acid alleviates gut damage induced by Salmonella pullorum in broilers by enhancing barrier function and modulating microbiota

Pullorum disease (PD) is a bacterial infection caused by Salmonella pullorum (S. pullorum) that affects poultry. It is highly infectious and often fatal. Antibiotics are currently the mainstay of prophylactic and therapeutic treatments for PD, but their use can lead to the development of resistance in pathogenic bacteria and disruption of the host's intestinal flora. We added neomycin sulfate and different doses of tannic acid (TA) to the drinking water of chicks at 3 days of age and infected them with PD by intraperitoneal injection of S. pullorum at 9 days of age. We analyzed intestinal histopathological changes and the expression of immune-related genes and proteins by using the plate smear method, histological staining, real-time fluorescence quantitative PCR, ELISA kits, and 16S rRNA Analysis of intestinal flora. The results demonstrate that S. pullorum induces alterations in the immune status and impairs the functionality of the liver and intestinal barrier. We found that tannic acid significantly ameliorated S. pullorum-induced liver and intestinal damage, protected the intestinal physical and chemical barriers, restored the intestinal immune barrier function, and regulated the intestinal flora. Our results showed that TA has good anti-diarrhoeal, growth-promoting, immune-regulating, intestinal barrier-protecting and intestinal flora-balancing effects, and the best effect was achieved at an additive dose of 0.2%.

Protective effects of feed additives on broiler chickens exposed to aflatoxins-contaminated feed: a systematic review and meta-analysis

Aflatoxin contamination in feed is a common problem in broiler chickens. The present systematic review and meta-analysis examined the impact of aflatoxin-contaminated feed and the efficacy of various feed additives on the production performance of broiler chickens fed aflatoxin-contaminated feed (AF-feed). A total of 35 studies comprising 53 AF-feed experiments were selected following PRISMA guidelines. Feed additives included in the analyses were toxins binder (TB), mannan-oligosaccharides (MOS), organic acid (OA), probiotics (PRO), protein supplementation (PROT), phytobiotics (PHY), and additive mixture (MIX). Random effects model and a frequentist network meta-analysis (NMA) were performed to rank the efficacy of feed additives, reported as standardized means difference (SMD) at 95% confidence intervals (95% CI). Overall, broiler chickens fed AF-feed had significantly lower final body weight (BW) (SMD = 198; 95% CI = 198 to 238) and higher feed conversion ratio (SMD = 0.17; 95% CI = 0.13 to 0.21) than control. Treatments with TB, MOS, and PHY improved the BW of birds fed AF-feed (P < 0.05) to be comparable with non-contaminated feed or control. Predictions on final BW from the broiler-fed aflatoxin-contaminated diet were 15% lower than the control diet. Including feed additives in the aflatoxins diet could ameliorate the depressive effect. Remarkably, our network meta-analysis highlighted that TB was the highest-performing additive (P-score = 0.797) to remedy aflatoxicosis. Altogether, several additives, especially TB, are promising to ameliorate aflatoxicosis in broiler chickens, although the efficacy was low regarding the severity of the aflatoxicosis.

Isolation and Proteomic Analysis of Extracellular Vesicles from Lactobacillus salivarius SNK-6

The proteins carried by the extracellular vesicles of Lactobacillus salivarius SNK-6 (LsEVs) were identified to provide a foundation for further explorations of the probiotic activities of L. salivarius SNK-6. LsEVs were isolated from the culture media of L. salivarius SNK-6 and morphological analysis was conducted by scanning electron microscopy. Subsequent transmission electron microscopy and nanoparticle tracking analysis were performed to assess the morphology and particle size of the LsEVs. In addition, the protein composition of LsEVs was analyzed using silver staining and protein mass spectrometry. Finally, internalization of the identified LsEVs was confirmed using a confocal microscope, and enzyme-linked immunosorbent assay was employed to analyze the levels of inflammatory cytokines in LPS-challenged RAW264.7 cells. The results revealed that the membrane-enclosed LsEVs were spherical, with diameters ranging from 100-250 nm. The LsEVs with diameters of 111-256 nm contained the greatest amount of cargo. In total, 320 proteins (10-38 kD) were identified in the LsEVs and included anti-inflammatory molecules, such as PrtP proteinase, co-chaperones, and elongation factor Tu, as well as some proteins involved in glycolysis/gluconeogenesis, such as fructose-1,6-bisphosphate aldolase. Enrichment analysis showed these proteins to be related to the terms "metabolic pathway," "ribosome," "glycolysis/gluconeogenesis," "carbohydrate metabolism," and "amino acid metabolism." Furthermore, the LsEVs were internalized by host liver cells and can regulate inflammation. These findings confirm that LsEVs contain various functional proteins that play important roles in energy metabolism, signal transduction, and biosynthesis.

Feather meal processing methods impact the production parameters, blood biochemical indices, gut function, and hepatic enzyme activity in broilers

This study investigated the effects of feather meal (FM) processing methods on production parameters, blood biochemical indices, intestinal morphology, digestive and hepatic enzyme activities, and gastrointestinal tract pH and microflora of broilers. A total of 480-d-old male broilers were used for 42 d in a completely randomized design with eight treatments and five replicates (12 chicks/replicate). Treatments were 1) a control diet (without FM), 2) a diet containing 4% raw FM (RFM), 3) a diet containing 4% processed FM (PFM) by autoclave (Au-PFM), 4) a diet containing 4% fermented FM (FFM) by Bacillus licheniformis (Bl-FFM), 5) a diet containing 4% FFM by Bacillus subtilis (Bs-FFM), 6) a diet containing 4% FFM by Aspergillus niger (An-FFM), 7) a diet containing 4% FFM by B. licheniformis + B. subtilis + A. niger (Co-FFM), and 8) a diet containing 4% PFM by an enzyme (En-PFM). Results showed that in the FFMs the contents of ash, ether extract, total volatile nitrogen, and amino acids including Lys, Met, Thr, Trp, His, Leu, Gly, Ile, Phe, and Tyr increased (P < 0.05), while crude fiber, crude protein, and dry matter content decreased (P < 0.05). Compared with the control, the Co-FFM diet had no significant differences (P > 0.05) in total body weight gain (2,827 vs. 2,791 g/chick), total feed intake (5,018 vs. 4,991 g/chick), European production efficiency factor (375 vs. 377), European Broiler Index (371 vs. 371), and feed conversion ratio (1.77 vs. 1.78 g/g). Feeding FFM decreased (P < 0.05) serum total cholesterol (1.46-fold), triglyceride (1.61-fold), very low-density lipoprotein cholesterol (1.61-fold), and low-density lipoprotein cholesterol (2.27-fold) compared to the control. Also, FFM increased (P < 0.05) villus height (1,045 to 1,351, 661 to 854, and 523 to 620 μm), and villus height to crypt depth ratio (6.15 to 8.45, 4.55 to 7.04, and 4.27 to 5.45), in the duodenum, jejunum, and ileum, respectively, compared to the control. Compared to the control, the Co-FFM diet increased (P < 0.05) protease (34, 39, and 45 %) in the pancreas, duodenum, and jejunum, as well as amylase (73, and 97 %) activities in the duodenum, and jejunum, respectively. Diets containing FFM reduced (P < 0.05) pH in the crop, gizzard, and ileum, and decreased (P < 0.05) Escherichia coli (6.12 to 5.70) count in ileum compared to the control. The Co-FFM diet increased (P < 0.05) lactic acid bacteria count in crop (6.77 to 7.50) and ileum (6.94 to 7.73), also decreased (P < 0.05) coliforms (6.31 to 5.75) count in ileum compared to the control. In conclusion, FM fermentation, particularly Co-FFM, improves the nutritional value of FM, converting it into a decent source of dietary protein for broilers.

Effects of lycopene on the growth performance, meat quality, and antioxidant capacity of broiler chickens challenged with aflatoxin B1

The present study aimed to investigate the effects of dietary lycopene (LYC) supplementation on the growth performance, meat quality, and antioxidant capacity of breast muscle in aflatoxin B1 (AFB1 )-challenged broilers. A total of 192 1-day-old healthy Arbor Acres broilers were randomly assigned to 3 treatments, each with 8 replicates (8 broilers per replicate). The broilers of the three treatments were fed a basal diet (control), a basal diet supplemented with 100 µg/kg AFB1 (CA), and a basal diet supplemented with 100 µg/kg AFB1 and 200 mg/kg LYC (CAL). The results demonstrated that the AFB1 diet increased the feed-to-gain (F/G) ratio (p < 0.05), yellowness and shear force of breast muscle (p < 0.05), and protein carbonyl (PC) content (p < 0.05) while decreasing the average daily gain (ADG) (p < 0.05), redness of breast muscle (p < 0.05), glutathione peroxidase activity (p < 0.05), and ability to clear OH· from breast muscle (p < 0.05) in comparison to the control group. Dietary LYC supplementation significantly decreased the F/G ratio (p < 0.05), yellowness and shear force (p < 0.05), and the content of PC and hydrogen peroxide (p < 0.05) while significantly increasing the ADG (p < 0.05), redness of breast muscle (p < 0.05), and ability of breast muscle to clear ABTS·+ (p < 0.05) compared to the CA diet. In conclusion, LYC can alleviate the negative impacts of AFB1 on the growth performance, meat quality, and antioxidant capacity of breast muscle in broilers. PRACTICAL APPLICATION: LYC, as a popular antioxidant, is beneficial to the growth and health of animals. The detailed application effects are still being investigated. In this study, by adding LYC to an AFB1 -contaminated diet, it was found that LYC could alleviate the adverse effects of AFB1 on the growth performance, meat quality, and muscle antioxidant capacity of broilers. These findings can provide a reference for the application of LYC and similar plant-derived materials in animal production.

Emerging perspectives in the gut-muscle axis: The gut microbiota and its metabolites as important modulators of meat quality

Animal breeding has made great genetic progress in increasing carcass weight and meat yield in recent decades. However, these improvements have come at the expense of meat quality. As the demand for meat quantity continues to rise, the meat industry faces the great challenge of maintaining and even increasing product quality. Recent research, including traditional statistical analyses and gut microbiota regulation research, has demonstrated that the gut microbiome exerts a considerable effect on meat quality, which has become increasingly intriguing in farm animals. Microbial metabolites play crucial roles as substrates or signalling factors to distant organs, influencing meat quality either beneficially or detrimentally. Interventions targeting the gut microbiota exhibit excellent potential as natural ways to foster the conversion of myofibres and promote intramuscular fat deposition. Here, we highlight the emerging roles of the gut microbiota in various dimensions of meat quality. We focus particularly on the effects of the gut microbiota and gut-derived molecules on muscle fibre metabolism and intramuscular fat deposition and attempt to summarize the potential underlying mechanisms.

Biogenic Selenium Nanoparticles Synthesized with Alginate Oligosaccharides Alleviate Heat Stress-Induced Oxidative Damage to Organs in Broilers through Activating Nrf2-Mediated Anti-Oxidation and Anti-Ferroptosis Pathways

Selenium (Se) is an essential trace element for maintaining health due to its ideal antioxidant properties. We previously prepared a new type of biogenic selenium nanoparticles based on alginate oligosaccharides (SeNPs-AOS), and this study aimed to investigate the protective effects of SeNPs-AOS (Se particle size = 80 nm, Se content = 8%) on organ health in broilers challenged with HS. A total of 192 21-day-old Arbor Acres broilers were randomly divided into four groups according to a 2 × 2 experimental design, including a thermoneutral zone group (TN, raised under 23 ± 1.5 °C); TN + SeNPs-AOS group (TN group supplemented 5 mg/kg SeNPS-AOS); HS group (HS, raised under 33 ± 2 °C for 10 h/day); and HS + SeNPs-AOS group (HS group supplemented 5 mg/kg SeNPS-AOS). There were six replicates in each group (eight broilers per replicate). The results showed that SeNPs-AOS improved the splenic histomorphology, enhanced the activity of catalase (CAT) and glutathione peroxidase (GSH-Px) of the spleen, as well as upregulating the splenic mRNA expression of antioxidant-related genes in broilers under HS. In addition, SeNPs-AOS reversed the pathological changes in bursa caused by HS increased the activity of GST, GSH-Px, and CAT and upregulated the mRNA expression of Nrf2 and antioxidant-related genes in the bursa of heat-stressed broilers. In addition, dietary SeNPs-AOS improved the hepatic damage, increased the activity of GSH-Px in the liver, and upregulated the mRNA expression of antioxidant-related genes while downregulating the Keap1 gene expression of the liver in broilers during HS. Moreover, dietary SeNPs-AOS upregulated the anti-ferroptosis-related genes expression of liver in broilers under HS. In conclusion, dietary SeNPs-AOS could relieve HS-induced oxidative damage to the spleen, bursa of Fabricius and liver in broilers by upregulating the Nrf2-mediated antioxidant gene expression and SeNPs-AOS could also upregulate the expression of hepatic Nrf2-related anti-ferroptosis genes in heat-stressed broilers. These findings are beneficial for the development of new nano-antioxidants in broilers.

Aflatoxin B1 Induces Inflammatory Liver Injury via Gut Microbiota in Mice

Aflatoxin B₁ (AFB₁), a potent food-borne hepatocarcinogen, is the most toxic aflatoxin that induces liver injury in humans and animals. Species-specific sensitivities of aflatoxins cannot be fully explained by differences in the metabolism of AFB₁ between animal species. The gut microbiota are critical in inflammatory liver injury, but it remains to reveal the role of gut microbiota in AFB₁-induced liver injury. Here, mice were gavaged with AFB₁ for 28 days. Then, the modulation of gut microbiota, colonic barrier, and liver pyroptosis and inflammation were analyzed. To further verify the direct role of gut microbiota in AFB₁-induced liver injury, mice were treated with antibiotic mixtures (ABXs) to deplete the microbiota, and fecal microbiota transplantation (FMT) was conducted. The treatment of AFB₁ in mice altered gut microbiota composition, such as increasing the relative abundance of Bacteroides, Parabacteroides, and Lactobacillus, inducing colonic barrier dysfunction and promoting liver pyroptosis. In ABX-treated mice, AFB₁ had little effect on the colonic barrier and liver pyroptosis. Notably, after FMT, in which the mice were colonized with gut microbiota from AFB₁-treated mice, colonic barrier dysfunction, and liver pyroptosis and inflammation were obliviously identified. We proposed that the gut microbiota directly participated in AFB₁-induced liver pyroptosis and inflammation. These results provide new insights into the mechanisms of AFB₁ hepatotoxicity and pave a window for new targeted interventions to prevent or reduce AFB₁ hepatotoxicity.

Dietary Probiotics Modulate Gut Barrier and Immune-Related Gene Expression and Histomorphology in Broiler Chickens under Non- and Pathogen-Challenged Conditions: A Meta-Analysis

Data published in the literature about the favorable effects of dietary probiotics on gut health in broiler chickens are inconsistent. To obtain a more comprehensive understanding, we conducted a meta-analysis to assess the effects of probiotics on the gut barrier and immune-related gene expression, histomorphology, and growth in chickens that were either challenged or non-challenged with pathogens. From the 54 articles published between 2012 and 2022, subsets of data, separately for non-challenged and challenged conditions, for response variables were created. The mean dietary probiotic concentrations ranged from 4.7 to 6.2 and 4.7 to 7.2 log₁₀ colony-forming unit/kg under non-challenged and challenged conditions, respectively. Probiotics increased the expression of genes for mucins and tight junction proteins in the jejunum and ileum at weeks 3 and 6. The stimulatory effect of probiotics on tight junction protein expression was partly stronger in challenged than in non-challenged birds. Meta-regressions also showed an anti-inflammatory effect of probiotics under challenged conditions by modulating the expression of cytokines. Probiotics improved villus height at certain ages in the small intestine while not influencing growth performance. Dietary metabolizable energy, crude protein, and days post-infection modified the effects of probiotics on the observed variables. Overall, meta-regressions support the beneficial effects of probiotics on gut integrity and structure in chickens.

Antimicrobial Drug Resistance in Poultry Production: Current Status and Innovative Strategies for Bacterial Control

The world population’s significant increase has promoted a higher consumption of poultry products, which must meet the specified demand while maintaining their quality and safety. It is well known that conventional antimicrobials (antibiotics) have been used in livestock production, including poultry, as a preventive measure against or for the treatment of infectious bacterial diseases. Unfortunately, the use and misuse of these compounds has led to the development and dissemination of antimicrobial drug resistance, which is currently a serious public health concern. Multidrug-resistant bacteria are on the rise, being responsible for serious infections in humans and animals; hence, the goal of this review is to discuss the consequences of antimicrobial drug resistance in poultry production, focusing on the current status of this agroeconomic sector. Novel bacterial control strategies under investigation for application in this industry are also described. These innovative approaches include antimicrobial peptides, bacteriophages, probiotics and nanoparticles. Challenges related to the application of these methods are also discussed.

Assessment of the safety and probiotic characteristics of Lactobacillus salivarius CGMCC20700 based on whole-genome sequencing and phenotypic analysis

Lactic acid bacteria are generally regarded as alternatives to antibiotics in livestock and poultry farming, especially Lactobacillus strains, which are safe and have probiotic potential. Although Lactobacillus salivarius has long been proposed to be a probiotic, the understanding of the roles of this species is still in its infancy. Here, a strain of L. salivarius CGMCC20700 isolated from the intestinal mucosa of Yunnan black-bone chicken broilers was investigated in the context of its safety and probiotic characteristics by whole-genome sequencing in parallel with phenotypic analysis. Whole-genome sequencing results showed that L. salivarius CGMCC20700 has a single scaffold of 1,737,577 bp with an average guanine-to-cytosine (GC) ratio of 33.51% and 1,757 protein-coding genes. The annotation of Clusters of Orthologous Groups (COG) classified the predicted proteins from the assembled genome as possessing cellular, metabolic, and information-related functions. Sequences related to risk assessment, such as antibiotic resistance and virulence genes, were identified, and the strain was further confirmed as safe according to the results of antibiotic resistance, hemolytic, and acute oral toxicology tests. Two gene clusters of antibacterial compounds and broad-spectrum antimicrobial activity were identified using genome mining tools and antibacterial spectrum tests. Stress resistance genes, active stressor removal genes, and adhesion related genes that were identified and examined with various phenotypic assays (such as stress tolerance tests in acids and bile salts and auto aggregation and hydrophobicity assays). The strain showed a high survival rate in the presence of bile salts and under acidic conditions and exhibited significant auto aggregation capacity and hydrophobicity. Overall, L. salivarius CGMCC20700 demonstrated excellent safety and probiotic potential at both the genomic and physiological levels and can be considered an appropriate candidate probiotic for livestock and poultry farming.

Effects of peroxisome proliferator activated receptor-α agonist on growth performance, blood profiles, gene expression related to liver fat metabolism in broilers fed diets containing corn naturally contaminated with mycotoxins

This study was conducted to determine the subclinical symptom of broilers exposure to mycotxoins from corn naturally contaminated, and the preventive effect with peroxisome proliferator activated receptor-α (PPARα) agonist (Wy-14643) supplementation. A total of 360 one-day -old male Arbor Acres broilers were randomly distributed into 4 treatments with 9 replicates of 10 birds. Dietary treatments included: treatment 1, normal corn diets group, treatment 2, normal corn + Wy-14643 diets group, treatment 3, mycotoxin-contaminated corn diets group, treatment 4, mycotoxin-contaminated corn + Wy-14643 diets group. The supplementation of Wy-14643 was added at the expense of 1 and 2 mg/kg in starter and grower diets, respectively. Birds fed mycotoxin diets had lower (P < 0.05) final body weight (BW), Body weight gain (BWG), feed intake (FI), and had higher (P < 0.05) feed conversion ratio (FCR). Feeding mycotoxin diets reduced (P < 0.05) the levels of serum superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT), total antioxidative capacity (T-AOC) and high-density lipoprotein cholesterol (HDL-C), but higher malondialdehyde (MDA), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and fatty acid synthetase (FAS). The supplementation of Wy-14643 increased (P < 0.05) the level of serum T-AOC, but reduced (P < 0.05) TG and LDL-C. Interactive effect was not observed (P > 0.05) in growth performance and blood profiles. The relative expression of PPARα mRNA and 3-Hydroxy-3-MethylGlutaryl-CO enzyme A (HMGCoA) mRNA was higher (P < 0.05) in treatment 3 and treatment 4 than treatment 1 and treatment 2, and there was significant difference (P <0.05) between treatment 3 and treatment 4. There was significant difference (P < 0.05) between groups of the relative expression of recombinant carnitine palmitoyl transferase 1 (CPT1) mRNA. The relative expression of acyl CoA oxidase (ACO) mRNA was higher (P < 0.05) in treatment 1 and treatment 4 than treatment 2 and treatment 3, and there was significant difference (P < 0.05) between treatment 1 and treatment 4. The relative expression of apolipoprotein A (APO-A) mRNA was higher (P < 0.05) in treatment 1 and treatment 4 than treatment 2 and treatment 3. The relative expression of sterol regulatory element binding protein (SREBP) mRNA was lower (P < 0.05) in treatment 2, treatment 3 and treatment 4 than treatment 1, and there was significant difference (P < 0.05) between treatment 3 and treatment 4. Overall, feeding naturally contaminated mycotoxin diets caused negative effects on growth performance and blood profiles, while diet supplementation with Wy-14643 alleviate the detrimental effects on gene and expression related to liver fat metabolism in broilers.

Cellular immune response after vaccination with Salmonella Gallinarum 9R in laying hens and addition of aflatoxin and absorbent in the feed

Salmonella Gallinarum greatly impacts commercial flocks and vaccination with S. Gallinarum 9R (SG9R) is one of the most effective control strategies in some countries. However, mycotoxins can affect immunization success. Herein, we measured the cellular immune response in SG9R-vaccinated hens, quantified the impact of aflatoxins on the immune response, and determined whether the anti-mycotoxin additive (adsorbent) influences immunity after vaccination. One-day-old chicks of commercial laying hens were raised until 49 days of age and were assigned to six groups. T1 (control group): control diet (no detectable concentration of aflatoxin), no vaccine or adsorbent. T2: vaccine SG-9R at day 28, aflatoxins 2.5 ppm from day 1 to day 49, and adsorbent 2.5 Kg/ton. T3: control diet and vaccine. T4: aflatoxins and vaccine. T5: control diet and aflatoxins. T6: aflatoxins and adsorbent. Body weights were evaluated on days 1, 31, and 41. Cellular immune response was evaluated by flow cytometry at 31, 41, and 49 days of age. T lymphocytes, B lymphocytes, monocytes, phagocytic monocytes and heterophils were evaluated. Aflatoxins suppressed peripheral and mucosal helper T lymphocytes, and mucosal cytotoxic T lymphocytes in vaccinated birds (T2 and T4). However, inclusion of the adsorbent in the feed of vaccinated birds neutralized the effects of aflatoxin (T6). The concentration of immune cells may show differences after SG9R vaccination, particularly an increase in the monocyte concentration. The SG9R vaccine reduced the concentration of activated cytotoxic T lymphocytes, making this marker a good parameter to analyze before and three weeks after immunization.

Effects of Dietary Pectin and Lactobacillus salivarius ATCC 11741 on Growth Performance, Immunocompetence, Gut Microbiota, Antioxidant Capacity, and Disease Resistance in Narrow-Clawed Crayfish, Postantacus leptodactylus

The present study was conducted to clarify the effects of Lactobacillus salivarius (LS) ATCC 11741 and pectin (PE) on growth performance, digestive enzymes activity, gut microbiota composition, immune parameters, antioxidant defense as well as disease resistance against Aeromonas hydrophila in narrow-clawed crayfish, Postantacus leptodactylus. During 18 weeks trial feeding, 525 narrow-clawed crayfish juvenile (8.07 ± 0.1 g) fed with seven experimental diets including control (basal diet), LS1 (1 × 10⁷ CFU/g), LS2 (1 × 109 CFU/g), PE1 (5 g/kg), PE2 (10 g/kg), LS1PE1 (1 × 10⁷ CFU/g +5 g/kg), and LS2PE2 (1 × 109 CFU/g +10 g/kg). After 18 weeks, growth parameters (final weight, weight gain, and specific growth rate) and feed conversion rate were significantly improved in all treatments (P < 0.05). Besides, diets incorporated with LS1PE1 and LS2PE2 significantly increased the activity of amylase and protease enzymes compared to LS1, LS2, and control groups (P < 0.05). Microbiological analyses revealed that the total heterotrophic bacteria count (TVC) and lactic acid bacteria (LAB) of narrow-clawed crayfish fed diets containing LS1, LS2, LS1PE1, and LS2PE2 were higher than control group. The highest total haemocyte count (THC), large-granular (LGC) and semigranular cells (SGC) count, and hyaline count (HC) was obtained in LS1PE1 (P < 0.05). Similarly, higher immunity activity (lysozyme (LYZ), phenoloxidase (PO), nitroxidesynthetase (NOs), and alkaline phosphatase (AKP)) observed in the LS1PE1 treatment compared to the control group (P < 0.05). The glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity remarkably enhanced in LS1PE1 and LS2PE2, while malondialdehyde (MDA) content reduced in these two treatments. In addition, specimens belonging to LS1, LS2, PE2, LS1PE1, and LS2PE2 groups presented higher resistance against A. hydrophila compared to the control group. In conclusion, feeding narrow-clawed crayfish with synbiotic had higher efficiency on growth parameters, immunocompetence, and disease resistance compared to single consumption of prebiotics and probiotics.

Effects of Compound Mycotoxin Detoxifier on Alleviating Aflatoxin B1-Induced Inflammatory Responses in Intestine, Liver and Kidney of Broilers

In order to alleviate the toxic effects of aflatoxins B1 (AFB1) on inflammatory responses in the intestine, liver, and kidney of broilers, the aflatoxin B1-degrading enzyme, montmorillonite, and compound probiotics were selected and combined to make a triple-action compound mycotoxin detoxifier (CMD). The feeding experiment was divided into two stages. In the early feeding stage (1−21 day), a total of 200 one-day-old Ross broilers were randomly divided into four groups; in the later feeding stage (22−42 day), 160 broilers aged at 22 days were assigned to four groups: Group A: basal diet (4.31 μg/kg AFB1); Group B: basal diet with 40 μg/kg AFB1; Group C: Group A plus 1.5 g/kg CMD; Group D: Group B plus 1.5 g/kg CMD. After the feeding experiment, the intestine, liver, and kidney tissues of the broilers were selected to investigate the molecular mechanism for CMD to alleviate the tissue damages. Analyses of mRNA abundances and western blotting (WB) of inflammatory factors, as well as immunohistochemical (IHC) staining of intestine, liver, and kidney tissues showed that AFB1 aggravated the inflammatory responses through NF-κB and TN-α signaling pathways via TLR pattern receptors, while the addition of CMD significantly inhibited the inflammatory responses. Phylogenetic investigation showed that AFB1 significantly increased interleukin-1 receptor-associated kinase (IRAK-1) and mitogen-activated protein kinase (MAPK) activities (p < 0.05), which were restored to normal levels by CMD addition, indicating that CMD could alleviate cell inflammatory damages induced by AFB1.

The effect of a postbiotic produced by stabilized non-viable Lactobacilli on the health, growth performance, immunity, and gut status of colisepticaemic broiler chickens

This work was designed to evaluate the efficacy of a postbiotic compound produced by stabilized non-viable Lactobacilli on the health, growth performance, immunity, and gut status against Escherichia coli (E. coli) challenge of broiler chickens. A total of 400, day-old broiler chicks were allocated into 4 equal groups (1–4) consisting of 100; each assigned into 2 equal replicates (50 each). Chickens in the 1st group were received the dry form of the compound at doses of 1 kg and 0.5 kg/ton feed for starter and grower, and the finisher diets, respectively. Chickens in the 2nd group were given the aqueous form of the compound in a dose of 4 mL/L of the drinking water during the first 3 days of life and at a day before and after each vaccination. Feed and water treatment regimens were administered to chickens in the 3rd group. Group 4 was kept without treatment. Each bird in the 1st, 2nd, 3rd, and 4th group was challenged with E. coli (O78) at 1-week-old. All groups were kept under observation till 5-week-old. Statistical analysis included one-way ANOVA and other methods as described with significant differences at P ≤ 0.05. The results indicated that feed and water treatments with the postbiotic compound induced more significant (P ≤ 0.05) amelioration of a disease picture, enhancement of growth performance, boosting of immune response, improvement of bursa of Fabricius/body weight ratio, and reduction of intestinal coliform count in challenged chickens when compared with challenged non-treated chickens. In conclusion, the postbiotic compound either in a dry and/or an aqueous form is recommended for improving the health, performance, and immunity of colisepticaemic broiler chickens.

Protective and detoxifying effects conferred by selenium against mycotoxins and livestock viruses: A review

Animal feed can easily be infected with molds during production and storage processes, and this can lead to the production of secondary metabolites, such as mycotoxins, which eventually threaten human and animal health. Furthermore, livestock production is also not free from viral infections. Under these conditions, the essential trace element, selenium (Se), can confer various biological benefits to humans and animals, especially due to its anticancer, antiviral, and antioxidant properties, as well as its ability to regulate immune responses. This article reviews the latest literature on the antagonistic effects of Se on mycotoxin toxicity and viral infections in animals. We outlined the systemic toxicity of mycotoxins and the primary mechanisms of mycotoxin-induced toxicity in this analysis. In addition, we pay close attention to how mycotoxins and viral infections in livestock interact. The use of Se supplementation against mycotoxin-induced toxicity and cattle viral infection was the topic of our final discussion. The coronavirus disease 2019 (COVID-19) pandemic, which is currently causing a health catastrophe, has altered our perspective on health concerns to one that is more holistic and increasingly embraces the One Health Concept, which acknowledges the interdependence of humans, animals, and the environment. In light of this, we have made an effort to present a thorough and wide-ranging background on the protective functions of selenium in successfully reducing mycotoxin toxicity and livestock viral infection. It concluded that mycotoxins could be systemically harmful and pose a severe risk to human and animal health. On the contrary, animal mycotoxins and viral illnesses have a close connection. Last but not least, these findings show that the interaction between Se status and host response to mycotoxins and cattle virus infection is crucial.

Evaluation of gum Arabic (Acacia Senegal) as a natural prebiotic to improve growth performance and health status of broiler chickens

Gum Arabic (GA) is a natural product containing soluble fiber that is indigestible in the gastrointestinal tract and has been used as a traditional medicine to treat many diseases such as intestinal inflammation, kidney disease, and liver disorders, which may be reflected in the improved performance of broiler chickens when used. Therefore, the main objective of the current study was to evaluate the effects of GA on the performance, immune system, visceral organs, functional tests, and histological changes of the ileum, liver, and kidneys of broilers. A total of 432 1-day-old male broilers were allocated to six dietary treatments (0.0, 0.12, 0.25, 0.5, 0.75, and 1.0% GA) for 35 days. Performance, internal organs, and blood biochemical indices were measured. Morphology and histometry of the intestine were also performed. Meanwhile, tissues of the ileum, liver, and kidney were examined and evaluated microscopically to observe histological changes. All levels of GA (0.12 to 1.0%) had a positive effect on growth performance and feed conversion ratio. In addition, GA had no effect on the relative weight of lymphoid and visceral organs, except for a linear response in the bursa and liver. The levels of GA (0.12 and 0.25%) showed the potential to decrease serum uric acid, creatinine, and alanine aminotransferase. The remarkable increase in small intestinal morphology of chickens fed GA and an increase in all histometric values of the ileum. All histological changes in the intestine, liver, and kidneys improved in chickens fed the basal diet containing 0.12 to 0.50% GA. These results provide useful evidence for the potential use of GA powder (Acacia senegal) as a natural prebiotic to improve performance and intestinal, liver, and kidney health in broiler chickens.

Recombinant Lactococcus lactis Expressing Grass Carp Reovirus VP6 Induces Mucosal Immunity Against Grass Carp Reovirus Infection

Grass carp haemorrhagic disease caused by grass carp reovirus II is a serious disease of the aquaculture industry and vaccination is the only effective method of GCRV protection. In this study, Lactococcus lactis was used as oral vaccine delivery to express the GCRV II VP6 protein. We evaluated the protective efficacy of the live vaccine strain to induce mucosal immune protection. After oral administration, the recombinant strains remained in the hindgut for antigen presentation and increased the survival rate 46.7% and the relative percent survival 42.9%, respectively versus control vaccination. Though L. lactis alone can induce the inflammatory response by stimulating the mucosal immune system, the recombinant L. lactis expressing VP6 greatly enhanced nonspecific immune responses via expression of immune related genes of the fish. Furthermore, both systemic and mucosal immunity was elicited following oral immunization with the recombinant strain and this strain also elicited an inflammatory response and cellular immunity to enhance the protective effect. L. lactis can therefore be utilized as a mucosal immune vector to trigger high levels of immune protection in fish at both the systemic and mucosal levels. L. lactis is a promising candidate for oral vaccine delivery.

Aflatoxin B1 exposure disrupts organelle distribution in mouse oocytes

Aflatoxin B1 (AFB1) is a secondary metabolite produced by the fungus Aspergillus, which is ubiquitous in moldy grain products. Aflatoxin B1 has been reported to possess hepatotoxicity, renal toxicity, and reproductive toxicity. Previous studies have shown that AFB1 is toxic to mammalian oocytes. However, the potential toxicity of AFB1 on the organelles of mouse oocytes is unknown. In this study, we found that exposure to AFB1 significantly reduced mouse oocyte development capacity. Further analysis showed that the endoplasmic reticulum (ER) failed to accumulate around the spindle, and scattered in the cytoplasm under AFB1 exposure. Similar to the ER, the Golgi apparatus showed a uniform localization pattern following AFB1 treatment. In addition, we found that AFB1 exposure caused the condensation of lysosomes in the cytoplasm, presenting as a clustered or spindle peripheral-localization pattern, which indicated that protein modification, transport, and degradation were affected. Mitochondrial distribution was also altered by AFB1 treatment. In summary, our study showed that AFB1 exposure had toxic effects on the distribution of mouse oocyte organelles, which further led to a decline in oocyte quality.

Effects of Chinese Gallnut Tannic Acid on Growth Performance, Blood Parameters, Antioxidative Status, Intestinal Histomorphology, and Cecal Microbial Shedding in Broilers Challenged with Aflatoxin B1

The objective of the present study was to investigate the effects of tannic acid (TA) on growth performance, blood parameters, antioxidant capacity, and intestinal health in broilers challenged with aflatoxin B1 (AFB1). A total of 480 1-d-old broilers were randomly allotted into 4 treatments: 1) CON, control diet, 2) AF, CON + 60 μg/kg AFB1 of feed during d 1 to 21, CON + 120 μg/kg AFB1 of feed during d 22 to 42, 3) TA1, AF +250 mg/kg TA, 4) TA2, AF +500 mg/kg TA. Average daily gain (ADG) and average daily feed intake (ADFI) were increased in the TA1 during d 1 to 21, d 22 to 42 and d1 to 42 compared with CON and AF treatments (P < 0.05). Broilers fed the TA2 diet had greater ADG and ADFI than those fed the CON and AF diets during the finisher and the whole period (P < 0.05). Administration of TA decreased the relative weight of liver and kidney compared with broilers fed the AF diet on d 42 (P < 0.05). The blood activity of alanine transferase (ALT) and gamma-glutamyl transferase (GGT) was increased in the AF treatment compared with the CON (P < 0.05). Broilers fed the TA1 decreased the ALT content on d 21, and the level of ALT and GGT was decreased in the TA2 compared with the AF group on d 42 (P < 0.05). The activity of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) in plasma, and the hepatic glutathione S-transferase (GST) was decreased in the AF group compared with the CON group (P < 0.05). The TA decreased plasma malondialdehyde concentration, and increased plasma T-SOD, GSH-Px, total antioxidant capacity, and hepatic GST activity compared to the AF (P < 0.05). The crypt depth of jejunum was decreased in the TA1 treatment on d 21, and the villus height of ileum was increased in the TA2 group on d 42 compared with the AF treatment (P < 0.05). The cecal Lactobacillus counts on d 21 was tended to increase in the TA treatments compared with the AF (P = 0.061). In conclusion, dietary inclusion of 250 mg/kg and 500 mg/kg TA could improve the growth, antioxidant capacity, and partially protected the intestinal health of broilers challenged with AFB1.

Non-Antibiotics Strategies to Control Salmonella Infection in Poultry

Salmonella spp. is a facultative intracellular pathogen causing localized or systemic infections, involving economic and public health significance, and remains the leading pathogen of food safety concern worldwide, with poultry being the primary transmission vector. Antibiotics have been the main strategy for Salmonella control for many years, which has allowed producers to improve the growth and health of food-producing animals. However, the utilization of antibiotics has been reconsidered since bacterial pathogens have established and shared a variety of antibiotic resistance mechanisms that can quickly increase within microbial communities. The use of alternatives to antibiotics has been recommended and successfully applied in many countries, leading to the core aim of this review, focused on (1) describing the importance of Salmonella infection in poultry and the effects associated with the use of antibiotics for disease control; (2) discussing the use of feeding-based (prebiotics, probiotics, bacterial subproducts, phytobiotics) and non-feeding-based (bacteriophages, in ovo injection, vaccines) strategies in poultry production for Salmonella control; and (3) exploring the use of complementary strategies, highlighting those based on -omics tools, to assess the effects of using the available antibiotic-free alternatives and their role in lowering dependency on the existing antimicrobial substances to manage bacterial infections in poultry effectively.