Effects of manganese and Bacillus subtilis on the reproductive performance, egg quality, antioxidant capacity, and gut microbiota of breeding geese during laying period

Impact of calsporin® (Bacillus subtilis C-3102) supplementation on growth performance and intestinal function in geese

The objective of this study was to preliminarily explore the effects of Calsporin® (Bacillus subtilis C-3102) on the growth performance, intestinal morphology, apparent digestibility, and cecal microbiota of geese. A total of 144 Sanhua geese, aged 35 days, were randomly divided into three groups: a control group, a group receiving a basal diet supplemented with 30 ppm Bacillus subtilis (B. subtilis), and a group receiving a basal diet supplemented with 60 ppm B. subtilis. Each group had six replicates, with eight geese per replicate. The study consisted of a one-week pre-feeding period followed by a four-week experimental period. The results indicated that, compared to the control group, the group supplemented with 60 ppm B. subtilis showed a significant increase in final body weight and the average daily gain (P < 0.05). Both the 30 ppm and 60 ppm B. subtilis groups exhibited significant improvements in the feed/gain (F/G) ratio (P < 0.05). Additionally, supplementation with either 30 ppm or 60 ppm B. subtilis significantly increased the height of the ileum villi (P < 0.05), with a trend towards an increased villus height to crypt depth (VH/CD) ratio (P > 0.05). In terms of digestive enzyme activity, both 30 ppm and 60 ppm B. subtilis supplementation significantly enhanced the activities of ileum cellulase and chymotrypsin (P < 0.05). Furthermore, the apparent digestibility of crude ash, crude protein, and Ca was significantly improved in the 60 ppm B. subtilis group (P < 0.05). Microbial analysis revealed that B. subtilis increased the abundance of potential probiotics bacterial families, such as Turicibacter, and butyrate-producing, including Prevotellaceae Ga6Al. In conclusion, supplementation with 60 ppm B. subtilis can significantly enhance the growth performance, intestinal morphology, and apparent digestibility of geese. Increasing the supplementation level may further optimize these benefits.

Effects of various supplemental levels of multi-enzyme complex on amino acid profiles in egg yolk, antioxidant capacity, cecal microbial community and metabolites of laying hens

This study aimed to investigate the effects of multi-enzyme (alkaline protease, xylanase, glucanase, β-mannanase, cellulase, acid protease, glucoamylase, and α-galactosidase) on antioxidant capacity, egg quality, amino acid profiles in yolk, cecal microflora and metabolites in laying hens. A total of 384 Jingfen No.6 laying hens aged 65 weeks were randomly divided into 4 treatments groups (6 replicates per group) and fed diets containing 0, 150, 300, or 600 mg kg-1 multi-enzyme over an 8-week feeding duration. Our findings revealed that supplementation with 600 mg kg-1 of multi-enzyme significantly increased the albumen height (P < 0.05) and haugh unit (P < 0.05). Moreover, as the levels of multi-enzyme supplementation in the diet increased, there were significant increases in activities of total antioxidant capacity (T-AOC) in serum (P < 0.05) and glutathione peroxidase (GSH-Px) in the liver (P < 0.05). Different levels of multi-enzyme supplementation significantly affected the composition of amino acid profiles in the yolk. Furthermore, the results from 16S rRNA sequencing and untargeted metabolomics analysis of cecal content revealed that multi-enzyme supplementation altered the cecal microflora and metabolite profiles. We found the relative abundance of the Bacteroidota phyla in T600 group was significantly increased (P < 0.05) compared to CON and T150 groups, but the relative abundance of the Firmicutes phylum in T600 group were significantly lower than T150 group (P < 0.05). At the genus level, the relative abundance of the Parabacteroides genera in T300 group, the Faecalibacterium genera in T300 and T600 groups, the norank_f_Prevotellaceae genera in treatment groups (T150, T300 and T600), the norank_f_Peptococcaceae genera in T600 group, and the Monoglobus genera in T1 group were significantly increased. The KEGG pathway analysis showed that the common enrichment metabolic pathways of each treatment group compared to the CON group were glycine, serine and threonine metabolism, foxo signaling pathway and mTOR signaling pathway, and the enrichment metabolic pathways shared by T300 vs CON and T600 vs CON was galactose metabolism and glycolysis/gluconeogenesis pathways. Correlation analysis identified notable relationships between specific microbes and metabolites with T-AOC in serum, GSH-Px activity in the liver, amino acids in yolk, albumen height, and haugh units. Overall, this study suggests that multi-enzyme supplementation regulated the cecal microbial community and metabolism, potentially influencing amino acid profiles in yolk, antioxidant capacity, and egg quality.

Metal(loid)-gut microbiota interactions and microbiota-related protective strategies: A review

Human exposure to metal(loid)s has dramatically increased over the past five decades, which has triggered public concern worldwide. Recently, gut microbiota has been considered a target for metal(loid)s, and some literature has reviewed the interactions between gut microbiota and heavy metal(loid)s (HMs) with high toxicity. However, whether there is an interaction between gut microbiota and metal(loid)s with essential roles or some normal functions are far from clear to date. Importantly, in addition to traditional probiotics that have been clarified to alleviate the adverse effect of HMs on the body, some novel probiotics, prebiotics, synbiotics, and postbiotics may also exhibit comparable or even better abilities of metal(loid) remediation. In this review, we mainly outline and discuss recent research findings on the metal(loid)-gut microbiota interactions and microbiota-related protective strategies.

Toxic and essential metals: metabolic interactions with the gut microbiota and health implications

Human exposure to heavy metals, which encompasses both essential and toxic varieties, is widespread. The intestine functions as a critical organ for absorption and metabolism of heavy metals. Gut microbiota plays a crucial role in heavy metal absorption, metabolism, and related processes. Toxic heavy metals (THMs), such as arsenic (As), mercury (Hg), lead (Pb), and cadmium (Cd), can cause damage to multiple organs even at low levels of exposure, and it is crucial to emphasize their potential high toxicity. Nevertheless, certain essential trace elements, including iron (Fe), copper (Cu), and manganese (Mn), play vital roles in the biochemical and physiological functions of organisms at low concentrations but can exert toxic effects on the gut microbiota at higher levels. Some potentially essential micronutrients, such as chromium (Cr), silicon (Si), and nickel (Ni), which were considered to be intermediate in terms of their essentiality and toxicity, had different effects on the gut microbiota and their metabolites. Bidirectional relationships between heavy metals and gut microbiota have been found. Heavy metal exposure disrupts gut microbiota and influences its metabolism and physiological functions, potentially contributing to metabolic and other disorders. Furthermore, gut microbiota influences the absorption and metabolism of heavy metals by serving as a physical barrier against heavy metal absorption and modulating the pH, oxidative balance, and concentrations of detoxification enzymes or proteins involved in heavy metal metabolism. The interactions between heavy metals and gut microbiota might be positive or negative according to different valence states, concentrations, and forms of the same heavy metal. This paper reviews the metabolic interactions of 10 common heavy metals with the gut microbiota and their health implications. This collated information could provide novel insights into the disruption of the intestinal microbiota caused by heavy metals as a potential contributing factor to human diseases.

Integrated omics analysis reveals a correlation between gut microbiota and egg production in captive African penguins (Spheniscus demersus)

The egg production of captive African penguins differs considerably between individuals. An understanding of the physiological differences in African penguins with relatively greater and lesser egg production is meaningful for the captive breeding program of this endangered species. The objective of this study was to investigate differential microbial composition and metabolites in captive African penguins with different egg production. Fecal samples were collected from captive female African penguins during the breeding season. The results of 16 S rRNA gene sequencing showed that African penguins with different egg production had similar microbial diversities, whereas a significant difference was observed between their microbial community structure. African penguins with relatively greater egg production exhibited a higher relative abundance of Alphaproteobacteria, Rhizobiales, Bradyrhizobiaceae, Bradyrhizobium and Bosea. Meanwhile, penguins with relatively lesser egg production had an increased proportion of Klebsiella and Plesiomonas. We further identified a total of 1858 metabolites in female African penguins by liquid chromatography-mass spectrometry analysis. Among these metabolites, 13 kinds of metabolites were found to be significantly differential between African penguins with different egg production. In addition, the correlation analysis revealed that the egg production had significant correlations with most of the differential microbial bacteria and metabolites. Our findings might aid in understanding the potential mechanism underlying the phenomenon of abnormal egg production in captive African penguins, and provide novel insights into the relationship between gut microbiota and reproduction in penguins.

Trace metal elements: a bridge between host and intestinal microorganisms

Trace metal elements, such as iron, copper, manganese, and zinc, are essential nutrients for biological processes. Although their intake demand is low, they play a crucial role in cell homeostasis as the cofactors of various enzymes. Symbiotic intestinal microorganisms compete with their host for the use of trace metal elements. Moreover, the metabolic processes of trace metal elements in the host and microorganisms affect the organism's health. Supplementation or the lack of trace metal elements in the host can change the intestinal microbial community structure and function. Functional changes in symbiotic microorganisms can affect the host's metabolism of trace metal elements. In this review, we discuss the absorption and transport processes of trace metal elements in the host and symbiotic microorganisms and the effects of dynamic changes in the levels of trace metal elements on the intestinal microbial community structure. We also highlight the participation of trace metal elements as enzyme cofactors in the host immune process. Our findings indicate that the host uses metal nutrition immunity or metal poisoning to resist pathogens and improve immunity.

The impact of Bacillus subtilis DSM32315 and L-Threonine supplementation on the amino acid composition of eggs and early post-hatch performance of ducklings

Poultry requires Threonine, an essential amino acid, and its metabolites for proper metabolic function. Threonine is crucial in the biosynthesis of mucin, which is essential for intestinal health and nutrient absorption. Bacillus subtilis (B. subtilis) is a potential substitute for antibiotic growth promoters in the poultry industry. The current study was designed to evaluate the simultaneous effect of L-Threonine (Thr) and B. subtilis DSM32315 supplementation on laying duck breeders in order to maximize performance. A total number of 648 female 23-week-old Longyan duck breeders were assigned to a 3 × 2 factorial design with six replicates of 18 birds per replicate. L-Thr was added to the control diet at concentrations of 0, 0.7, and 1.4 g/kg, equating to 3.9, 4.6, and 5.3 g Thr/kg, with or without B. subtilis strain DSM 32315 (0.0 and 0.5 g/kg). Increasing Thr concentrations improved egg production and ducklings' hatchling weight (p < 0.05). In addition, L-Thr supplementation resulted in a tendency for decreased feed conversion ratio without affecting egg quality. There was no significant effect (p > 0.05) of the dietary Thr levels on egg yolk and albumen amino acid concentrations. In contrast, the addition of B. subtilis decreased the concentrations of amino acids, excluding proline, in the egg white (albumen) and the egg yolk (p < 0.05). Furthermore, the supplementation of B. subtilis decreased (p < 0 0.001) the hatching weight of ducklings. The addition of B. subtilis without L-Thr decreased (p < 0.05) the hatchability of fertile eggs and the hatching weight of ducklings compared to those of ducks fed dietary L-Thr along with B. subtilis (p < 0.001). The combining L-Thr at 0.7 g/kg with B. subtilis DSM 32315 at 0.5 g/kg could increase eggshell quality, hatchability, and hatching weight. The current study revealed that the combination supplemented of L-Thr and B. subtilis DSM 32315 is recommended due to its positive effects on the eggshell percentage, hatchability and the body weights of newly hatched ducklings when dietary Thr was added at a rate of 0.7 g/kg and B. subtilis DSM 32315 at 0.5 g/kg. In addition, adding L-Thr separately at 0.7 g/kg could improve the egg production of duck breeders. Further studies are required to find the proper dosages of B. subtilis DSM 32315 with co-dietary inclusion of limiting amino acids in the diets of duck breeders. The findings of these trials will support feed additive interventions to transition into antibiotic-free diets.

Control of nutrient metal availability during host-microbe interactions: beyond nutritional immunity

The control of nutrient availability is an essential ecological function of the host organism in host-microbe systems. Although often overshadowed by macronutrients such as carbohydrates, micronutrient metals are known as key drivers of host-microbe interactions. The ways in which host organisms control nutrient metal availability are dictated by principles in bioinorganic chemistry. Here I ponder about the actions of metal-binding molecules from the host organism in controlling nutrient metal availability to the host microbiota. I hope that these musings will encourage new explorations into the fundamental roles of metals in the ecology of diverse host-microbe systems.

Comparison of the Effects between Tannins Extracted from Different Natural Plants on Growth Performance, Antioxidant Capacity, Immunity, and Intestinal Flora of Broiler Chickens

In this study, four plant tannins, including AT (Acacia mearnsii tannin, 68%), CT (Castanea sativa tannin, 60%), QT (Schinopsis lorenzii tannin, 73%) and TT (Caesalpinia spinosa tannin, 50%) were added to broiler diets for 42 days to evaluate and compare their effects on growth performance, antioxidant capacity, immune performance and gut microbiota in broilers. The results showed that the supplementation of five tannins could increase the production of T-AOC, GSH-Px, SOD and CAT and reduce the production of MDA in the serum of broilers (p < 0.01), but the antioxidant effect of the AT group was lower than that of the other three groups (p < 0.01). All four tannins decreased the level of the pro-inflammatory factor IL-1β and increased the level of the anti-inflammatory factor IL-10 (p < 0.01). CT, QT and TT decreased the levels of pro-inflammatory factors IL-6 and TNF-α (p < 0.01), while AT and CT increased the level of IL-2 in serum (p < 0.01). Supplementation with four tannins also increased the levels of IgG, IgM, IgA and sIgA in serum (p < 0.01) and the levels of ZO-1, claudin-1 and occludin in the jejunum (p < 0.01). The detection results of ALT and AST showed that CT, QT and TT decreased the concentrations of ALT and AST in serum (p < 0.01). The results of the gut microbiota showed that the abundance of Clostridia and Subdoligranulum increased, and the abundance of Oscillospiraceae decreased, compared to the control group after adding the four tannins to the diets (p > 0.05). In addition, CT, QT and TT decreased the abundance of Lactobacillus and increased the abundance of Bacteroides compared to the control group, while AT showed the opposite result (p > 0.05). Overall, our study shows that tannins derived from different plants have their own unique effects on broilers. AT and CT can promote broilers' growth better than other tannins, CT has the best ability to improve immune and antioxidant properties, and QT and TT have the best effect on broilers' liver protection.

Dietary supplementation with fermented plant product modulates production performance, egg quality, intestinal mucosal barrier, and cecal microbiota in laying hens

Fermented plant product (FPP) is a kind of functional complex containing probiotics and a variety of bioactive substances, which has multiple physiological functions. However, there is no systematic appraisal of FPP as a feed additive for laying hens. This study was conducted to evaluate the utilization of FPP in laying hens. A total of 120 healthy 34-week-old Xianju layers with similar body weight and egg production were randomly allocated into two dietary treatments with four replicates per treatment and 15 birds per replicate for 8 weeks. The dietary treatments included the basal diet without FPP (CON group) and CON diet supplemented with 500 mg/kg of FPP (FPP group). Compared with the CON group, the egg production and egg mass were significantly increased in the FPP group from 38 to 42 and 34 to 42 weeks of age (P < 0.05). Birds fed with the diet containing 500 mg/kg FPP had higher albumen height (P < 0.01) and Haugh unit (P < 0.05) than those of the controls. FPP supplementation significantly increased the villus height (VH) and crypt depth (CD) in the jejunum of laying hens (P < 0.01), as well as the ratio of VH to CD (P < 0.05). The mRNA expression of tight junctions showed that dietary supplementation with FPP significantly increased the expression levels of Occludin (P < 0.01) and ZO-1 (P < 0.05) in jejunum of hens compared to the control group. In addition, dietary supplementation with FPP influenced cecal microbiota of laying hens, which was characterized by the changes in the microbial community composition, including the increased abundances of Firmicutes, Faecalibacterium, Oscillospira, Clostridium, Ruminococcus, and Coprococcus, along with the decreased abundance of Bacteroidetes, Proteobacteria, Phascolarctobacterium, Odoribacter, Desulfovibrio, and Mucispirillum. Spearman's correlation analysis revealed that bacteria such as Faecalibacterium, Ruminococcus, Coprococcus, and Blautia were significantly and positively correlated with the intestinal barrier markers (P < 0.05), with extremely significant correlations between Ruminococcus and ZO-1, and Coprococcus and Occludin (P < 0.01), whereas Desulfovibrio had a negative correlation with the expression of Occludin (P < 0.05). As it can be concluded, FPP supplementation increased the egg production, egg mass, albumen height, and Haugh unit of laying hens, and improved intestinal health by ameliorating intestinal barrier function, which may be partially attributed to the regulation of cecal microbiota. Our findings suggest that FPP has the potential to be used as a feed additive to promote the performance of layers.

Effects of Dietary Bopu Powder Supplementation on Serum Antioxidant Capacity, Egg Quality, and Intestinal Microbiota of Laying Hens

The purpose of this study was to investigate the effects of dietary Bopu powder supplementation on the serum antioxidant capacity, serum biochemical indices, egg quality, and intestinal microbiota. Six hundred and forty-eight 33-week-old Lohmann Brown commercial laying hens were randomly allocated into six groups and fed a basal diet supplemented with 0, 25, 50, 100, 200, and 400 mg/kg Bopu powder for 8 weeks, denoted BP0, BP25, BP50, BP100, BP200, and BP400, respectively. The results showed that dietary Bopu powder supplementation reduced serum cholesterol concentrations (linear, p < 0.01) while increasing serum globulin and albumin concentrations (linear, p < 0.05). Furthermore, the BP50 and BP100 groups had greater serum catalase and glutathione peroxidase activity (p < 0.05). The egg Haugh Units were considerably higher in BP25 and BP50 (p < 0.05), and eggshell thickness was higher in BP25, BP200, and BP400 (p < 0.05) when compared to BP0. Dietary treatment with Bopu powder at doses ranging from 25–100 mg/kg improved glutathione peroxidase and catalase activities while decreasing malondialdehyde concentrations in the yolk (p < 0.05). The addition of Bopu powder increased the diversity of microbiota and the relative abundance of Bacteroidota in the gut. For instance, dietary Bopu powder supplementation of 25–50 mg/kg significantly raised the relative abundance of Enterococcus, Bacteroides, and Fusobacterium in the foregut. Supplementing the diet with 50–100 mg/kg of Bopu powder improved the relative abundance of Lactobacillus in the hindgut. In conclusion, dietary Bopu powder supplementation enhanced the abundance of beneficial bacteria in the foregut of laying hens and improved egg quality and antioxidant capacity. Furthermore, in the laying hen diet, the optimal dosage of Bopu powder additive was 25–50 mg/kg.

Effects of zinc and Bacillus subtilis on the reproductive performance, egg quality, nutrient digestion, intestinal morphology, and serum antioxidant capacity of geese breeders

The effects of zinc (Zn) and Bacillus subtilis (B. subtilis) on reproductive performance, egg quality, nutrient digestion, intestine morphology, and antioxidant capacity were explored in geese breeders. Geese breeders (n = 120, 46-wk of age) were randomly assigned into 6 groups with 4 replicates of 5 birds each (1 male and 4 female). Breeders were fed diets with 2 levels of B. subtilis (2.5 × 10⁹ and 5 × 10⁹ CFU/kg) crossed with three levels of Zn (25, 45, and 65 mg/kg) for duration of 10-wk. The results showed that the egg laying rate (P < 0.05), fertility rate (P < 0.01), hatchability rate (P < 0.05), yolk color (P < 0.05), and the retentions of crude protein (P < 0.05), ether extract (P < 0.05) and phosphorus of geese breeders were improved by dietary supplementation of 5 × 10⁹ CFU/kg B. subtilis and 25 mg or 45 mg/kg Zn. The serum T-SOD (P < 0.05) was increased by 45 mg/kg Zn supplementation. The serum T-AOC (P < 0.05) and retention of Zn (P < 0.05) were increased by 5 × 10⁹ CFU/kg B. subtilis supplementation. The birds fed with 5 × 10⁹ CFU/kg B. subtilis and 25 mg or 45 mg/kg Zn showed improved villus length (P < 0.01) and villus length/ crypt depth (P < 0.01) in both the jejunum and ileum. In conclusion, the combination of B. subtilis and Zn may have synergistic effects on these parameters, and dietary inclusion of 5 × 10⁹ CFU/kg B. subtilis and 45 mg/kg Zn is recommended for improving the reproductive performance of geese breeders.

Does gut microbiota regulate brooding in geese?

Domestic geese can reduce the amount of food intake when brooding. Because of the reduction in food intake, the total number of microorganisms in the gut is also reduced. Will this affect the goose’s thinking and make the goose stop brooding and eat food? We hypothesize that gut microbiota affects the brain through a brain–gut peptide and further regulates the breeding behavior of geese. In this study, we evaluated the microbiome related to the goose and transcription groups of brooding and egg production periods. The changes and differences in gut microbiota and gene expression of female geese in different reproduction periods were analyzed, and the possible interaction between them was explored. The results showed that the relative abundance of Faecalibacterium with a growth-promoting effect in the cecum was higher in the egg production group than in the brooding group. Microbial metabolic pathways with significant differences between the two groups were also enriched in the secondary functional groups with different gut microbiota metabolism. The downregulated genes in the egg production group were mainly related to energy metabolism, such as ATP synthesis-related genes. These results suggest that the brooding group’s gut microbiota can make relevant changes according to the reproduction stage of the goose. Since the amount of food taken in is reduced, it can promote the decomposition of the host’s fat. Simultaneously, insulin is also used to deliver messages to the brain; it is necessary to end the brooding behavior at an appropriate time and for eating to start.

Grazing and Supplementation of Dietary Yeast Probiotics Shape the Gut Microbiota and Improve the Immunity of Black Fattening Goats (Capra hircus)

This study aimed to investigate the effects of different feeding modes on the growth performance, gut microbiota, and immunity of Black Fattening Goat (Capra hircus). A total of 30 goats were grouped in three groups by their feeding modes (pasture grazing group, PG; barn feeding group, BF; barn feeding + probiotics, BF + P; n = 10) and the study was performed for 114 days. After a 2-week adaptation period, the first growth performance test was conducted, and the blood and fecal samplings (day 0) were collected on January 17, 2020, while the second and third test and samplings were conducted on days 53 and 100 of feeding. The species-composition of fecal microbiota was analyzed by 16S ribosomal RNA gene-sequencing using PacBio single molecule real time (SMRT) sequencing technology. Both the BF and BF + P groups had the highest (P < 0.05) body’s weight and length, and chest circumference at days 53 and 100, especially at day 100, the body’s weight of both the BF groups were more than 18 kg. The levels of immunoglobulin A (IgA) and immunoglobulin G (IgG) were found to be significantly higher (P < 0.05) in the PG and BF + P groups at day 100. The PG group exhibited the highest number of operational taxonomic unit (OTUs) and alpha diversity. Firmicutes, Bacteroidetes, and Verrucomicrobia were the predominant phyla in all the fecal samples. The relative abundance of Akkermansia muciniphila and Ruminococcus flavefaciens were found to be significantly higher (P < 0.05) in PG group and BF + P group at day 100, respectively, which might partially explain the significantly higher (P < 0.05) levels of IgA and IgG in these two groups. These findings suggested that BF supplemented with 5 g probiotics (Saccharomyces cerevisiae and mannan oligosaccharides) per day has the potential to enhance the growth and immunity of Black Fattening Goats.

Gut Microbiota as a Potential Player in Mn-Induced Neurotoxicity

Manganese (Mn) is an essential metal, which at high exposures causes neurotoxic effects and neurodegeneration. The neurotoxic effects of Mn are mediated by neuroinflammation, oxidative and endoplasmic reticulum stress, mitochondrial dysfunction, and other mechanisms. Recent findings have demonstrated the potential impact of Mn overexposure on gut microbiota dysbiosis, which is known to contribute to neurodegeneration via secretion of neuroactive and proinflammatory metabolites. Therefore, in this review, we discuss the existing data on the impact of Mn exposure on gut microbiota biodiversity, bacterial metabolite production, and gut wall permeability regulating systemic levels. Recent data have demonstrated that Mn exposure may affect gut microbiota biodiversity by altering the abundance of Shiegella, Ruminococcus, Dorea, Fusicatenibacter, Roseburia, Parabacteroides, Bacteroidetes, Firmicutes, Ruminococcaceae, Streptococcaceae, and other bacterial phyla. A Mn-induced increase in Bacteroidetes abundance and a reduced Firmicutes/Bacteroidetes ratio may increase lipopolysaccharide levels. Moreover, in addition to increased systemic lipopolysaccharide (LPS) levels, Mn is capable of potentiating LPS neurotoxicity. Due to the high metabolic activity of intestinal microflora, Mn-induced perturbations in gut microbiota result in a significant alteration in the gut metabolome that has the potential to at least partially mediate the biological effects of Mn overexposure. At the same time, a recent study demonstrated that healthy microbiome transplantation alleviates Mn-induced neurotoxicity, which is indicative of the significant role of gut microflora in the cascade of Mn-mediated neurotoxicity. High doses of Mn may cause enterocyte toxicity and affect gut wall integrity through disruption of tight junctions. The resulting increase in gut wall permeability further promotes increased translocation of LPS and neuroactive bacterial metabolites to the systemic blood flow, ultimately gaining access to the brain and leading to neuroinflammation and neurotransmitter imbalance. Therefore, the existing data lead us to hypothesize that gut microbiota should be considered as a potential target of Mn toxicity, although more detailed studies are required to characterize the interplay between Mn exposure and the gut, as well as its role in the pathogenesis of neurodegeneration and other diseases.

Sex differences in growth performance are related to cecal microbiota in chicken

In poultry industry, male chickens have a better growth performance than female ones under the same genetic background and diet. Emerging evidences proposed an important role of intestinal microbiota in chicken's growth performance. This study aimed to determine gut microbiota related gender based differences in the growth performance of chickens. Therefore, male and female chickens (n = 20) at 7-week age were used to carry out histomorphological, molecular, gene expression analysis with their liver, chest and leg muscle, as well as 16S rRNA sequencing analysis for gut microbiota. The results revealed that Bacteroides and Megamonas genera were more prominently colonized in the cecum of male chickens. The male chicken's cecal microbiota indicated a closer relation with glycan metabolism, while in the female chickens it was more related with lipid metabolism. Gene expression levels associated with glycan and lipid metabolism were different between male and female chickens. Further, using Spearman correlation analysis, we found a positive correlation between glycan and lipid metabolism, and the relative abundance of Bacteroides, Megamona and Lactobacillus in male chickens. Similarly, we also found a positive correlation between the lipid metabolism and the relative abundance of Ruminococcaceae and Enterococcus in female chickens. These findings revealed the association of chicken growth performance with cecal microbiota that contributed to the metabolism of glycan and lipid in a sex-dependent manner.