Proteome and microbiota analysis reveals alterations of liver-gut axis under different stocking density of Peking ducks

Effects of stocking density on the homeostasis of uric acid and related liver and kidney functions in ducks

OBJECTIVE

Stocking density (SD) is an important issue in the poultry industry, which is related to the production performance, intestinal health and immune status. In the present study, the effects of SD on the metabolism and homeostasis of uric acid as well as the related functions of the liver and kidney in ducks were examined.

METHODS

A total of 360 healthy 56-day-old Shan-ma ducks were randomly divided into the low stocking density (n = 60, density = 5 birds/m2), medium stocking density (n = 120, density = 10 birds/m2) and high stocking density groups (HSD; n = 180, density = 15 birds/m2). Samples were collected in the 3rd, 6th, and 9th weeks of the experiment for analysis.

RESULTS

The serum levels of uric acid, lipopolysaccharide and inflammatory cytokines (interleukin-1β [IL-1β], IL-8, and tumor necrosis factor-α [TNF-α]) were increased significantly in the HSD group. Serious histopathological lesions could be seen in both the livers and kidneys in the HSD group in the 9th week. The mRNA expression levels of inflammatory cytokines (IL-8 and TNF-α) and related pathway components (toll-like receptor 4, myeloid differentiation primary response gene 88, and nuclear factor-κB) were increased significantly in both the livers and kidneys in the HSD group. The mRNA expression levels of enzymes (adenosine deaminase, xanthine oxidase, phosphoribosyl pyrophosphate amidotransferase, and phosphoribosyl pyrophosphate synthetase 1) related to the synthesis of uric acid increased significantly in the livers in the HSD group. However, the mRNA expression level of solute carrier family 2 member 9, which plays an important role in the excretion of uric acid by the kidney, was decreased significantly in the kidneys in the HSD group.

CONCLUSION

These results indicated that a higher SD could cause tissue inflammatory lesions in the liver and kidney and subsequently affect the metabolism and homeostasis of uric acid, and is helpful for guiding decisions related to the breeding and production of ducks.

Stress-Related Gene Expression in Liver Tissues from Laying Hens Housed in Conventional Cage and Cage-Free Systems in the Tropics

Global egg production is mainly based on cage systems, which have been associated with negative effects on the welfare of birds. Stress factors in restrictive production systems can lead to changes in gene transcription and protein synthesis, ultimately impacting the quality of poultry products. The liver serves various metabolic functions, such as glycogen storage, and plays a crucial role in animals' adaptation to environmental changes. Consequently, both internal and external conditions can influence liver functions. The aim of this study was to evaluate the gene expression of AGP, CRP, NOX4, SOD1, CAT, GPX1, SREBF1, and FXR in the liver of laying hens under two different production systems. Liver tissues from Hy-Line Brown hens housed in conventional cage and cage-free egg production systems at 60 and 80 weeks of production were used. mRNA transcript levels were determined by qPCR using the relative quantification method and ACTB as the reference gene. AGP, SOD1, and SREBF1 gene expressions were significantly higher in the conventional cage group at the 60 weeks of production. Furthermore, the mRNA levels of transcripts related to oxidative stress and lipid metabolism were higher in the group of laying hens housed in conventional cages compared to those in cage-free systems. These results suggest differential gene expression of genes related to oxidative stress in liver tissues from hens housed in conventional cages compared to cage-free systems. The conditions of the egg production system can impact the gene expression of oxidative stress and lipid synthesis genes, potentially leading to changes in the metabolism and performance of hens, including egg quality.

The toxic mechanism of 6:2 Cl-PFESA in adolescent male rats: Endocrine disorders and liver inflammation regulated by the gut microbiota-gut-testis/liver axis

In previous studies, 6:2 chlorinated polyfluorinated ether sulfonic acid (6:2 Cl-PFESA), a perfluorooctanesulfonate alternative, has been demonstrated to be toxic to mammals. However, the toxic mechanism of 6:2 Cl-PFESA in mammals is unknown. Herein, adolescent male rats were administered 50 μg/kg/Day 6:2 Cl-PFESA for 28 days (oral gavage) to estimate the toxicity of 6:2 Cl-PFESA and investigate its toxic mechanism. Significant changes in some hematological indicators (e.g., aspartate transaminase and neutrophils) and liver sections (inflammatory cell infiltration) indicated that 6:2 Cl-PFESA exposure caused rat hepatotoxicity. Six steroid hormones (e.g., testosterone, progesterone, and cortisol) in serum and thirteen genes in testicles (related to the pathway of steroid hormone biosynthesis) were significantly regulated in 6:2 Cl-PFESA-treated rats. This suggested that 6:2 Cl-PFESA induced rat endocrine disorders. Compared to the controls, the mean relative abundance of Ruminococcaceae, Pasteurellaceae, Micrococcaceae, and Desulfovibrionaceae was significantly regulated by 1.3-, 0.40-, 0.32-, and 3.2-fold in the 6:2 Cl-PFESA rats, respectively. The 6:2 Cl-PFESA treatment also significantly disturbed 47 gut metabolites (29 upregulated and 18 downregulated), mainly bile acids, short-chain fatty acids, and amino acids. In summary, 6:2 Cl-PFESA induced endocrine disorders and liver inflammation in rats by altering the gut microbiota-gut-testis/liver axis. This study first reveals the toxic mechanism of 6:2 Cl-PFESA in mammals through a multiomics approach and provides comprehensive insight into the toxic mechanism of 6:2 Cl-PFESA.

Effects of ultrasound-induced stress on gut microbiota of mice

Background and Aim

Prolonged stress causes deleterious effects on both the organism and its microbiota. In this study, we examined the effects of exposure to variable frequency ultrasound (US) on the gut microbiota-liver-brain axis of mice.

Materials and Methods

This study was conducted on 20 mature clinically healthy sexually naive C57BL/6J male mice (42-45 days old). Group 1 (Normal) consisted of healthy intact mice (n = 10). Group 2 (Stress) consisted of mice subjected to US-induced stress (n = 10) for 20 days with alternating frequencies (20-45 kHz). Stool samples were collected on days 0, 10, and 20, and the corresponding DNA was later subjected to 16SrRNA sequencing. After mice were sacrificed on day 21, the leukocyte count, blood serum biochemical parameters, and liver and brain antioxidant status were measured. Behavioral testing was performed on days 17, 18, and 19.

Results

Ultrasound lead to higher stress and anxiety levels; increase in creatinine by 8.29% and gamma-glutamyltransferase activity by 5 times, a decrease in alkaline phosphatase activity by 38.23%, increase of de Ritis coefficient by 21.34%; increased liver and brain superoxide dismutase level by 20.8% and 21.5%, respectively; the stress-related changes in the gut microbiota composition - Bacteroidaceae and Firmicutes.

Conclusion

Subjecting mice to 20 days of US-induced stress leads to systemic disorders due to oxidative stress and a decrease in the diversity of the gut microbiota.

Egg-laying capacity of parent flock geese at different stocking densities

This article presents the results of studies aimed at establishing the optimal stocking density of purebred and hybrid geese of the parent flock, taking into account the indicators of their live weight and egg production. When conducting research, the stocking density of geese was established depending on the breed and shape. Different stocking densities of geese in groups were achieved due to their different numbers in groups: Kuban 1.2; 1.5; 1.8 birds/m² , large gray 0.9; 1.2; 1.5 birds/m² , hybrid bird 1.0; 1.3; 1.5 birds/m² . It was revealed on the basis of the analysis of the productive qualities of adult geese that the optimal planting density of the Kuban geese is 1.8 heads/m² , large sulfur = 0.9, hybrid = 1.3. The safety of geese at a given stocking density ensured an increase in the safety of geese of the Kuban breed by 95.3%, large gray = 94.0%, hybrid = 97.0%. The live weight of Kuban geese increased by 0.9%, large gray geese = 0.10, hybrids = 1.2, egg production by 0.6%, 2.2% and 0.5%, respectively.

Effects of Housing System on Anxiety, Chronic Stress, Fear, and Immune Function in Bovan Brown Laying Hens

The scientific community needs objective measures to appropriately assess animal welfare. The study objective was to assess the impact of housing system on novel physiological and behavioral measurements of animal welfare for laying hens, including secretory and plasma Immunoglobulin (IgA; immune function), feather corticosterone (chronic stress), and attention bias testing (ABT; anxiety), in addition to the well-validated tonic immobility test (TI; fearfulness). To test this, 184 Bovan brown hens were housed in 28 conventional cages (3 birds/cage) and 4 enriched pens (25 birds/pen). Feces, blood, and feathers were collected 4 times between week 22 and 43 to quantify secretory and plasma IgA and feather corticosterone concentrations. TI tests and ABT were performed once. Hens that were from cages tended to show longer TI, had increased feather corticosterone, and decreased secretory IgA at 22 weeks of age. The caged hens fed quicker, and more hens fed during the ABT compared to the penned hens. Hens that were in conventional cages showed somewhat poorer welfare outcomes than the hens in enriched pens, as indicated by increased chronic stress, decreased immune function at 22 weeks of age but no other ages, somewhat increased fear, but reduced anxiety. Overall, these novel markers show some appropriate contrast between housing treatments and may be useful in an animal welfare assessment context for laying hens. More research is needed to confirm these findings.

Environmental Stress in Chickens and the Potential Effectiveness of Dietary Vitamin Supplementation

Environmental stressors can promote the vulnerability of animals to infections; it is therefore, essential to understand how stressors affect the immune system, the adaptive capacity of animals to respond, and effective techniques in managing stress. This review highlights scientific evidence regarding environmental stress challenge models and the potential effectiveness of vitamin supplementation. The major environmental stressors discussed are heat and cold stress, feed restriction, stocking density, and pollutants. Much work has been done to identify the effects of environmental stress in broilers and layers, while few involved other types of poultry. Studies indicated that chickens' performance, health, and welfare are compromised when challenged with environmental stress. These stressors result in physiological alterations, behavioral changes, decreased egg and meat quality, tissue and intestinal damage, and high mortalities. The application of vitamins with other nutritional approaches can help in combating these environmental stressors in chickens. Poultry birds do not synthesize sufficient vitamins during stressful periods. It is therefore suggested that chicken diets are supplemented with vitamins when subjected to environmental stress. Combination of vitamins are considered more efficient than the use of individual vitamins in alleviating environmental stress in chickens.

Metabolome and Microbiota Analysis Reveals the Conducive Effect of Pediococcus acidilactici BCC-1 and Xylan Oligosaccharides on Broiler Chickens

Xylan oligosaccharides (XOS) can promote proliferation of Pediococcus acidilactic BCC-1, which benefits gut health and growth performance of broilers. The study aimed to investigate the effect of Pediococcus acidilactic BCC-1 (referred to BBC) and XOS on the gut metabolome and microbiota of broilers. The feed conversion ratio of BBC group, XOS group and combined XOS and BBC groups was lower than the control group (P < 0.05). Combined XOS and BBC supplementation (MIX group) elevated butyrate content of the cecum (P < 0.05) and improved ileum morphology by enhancing the ratio of the villus to crypt depth (P < 0.05). The 16S rDNA results indicated that both XOS and BBC induced high abundance of butyric acid bacteria. XOS treatment elevated Clostridium XIVa and the BBC group enriched Anaerotruncus and Faecalibacterium. In contrast, MIX group induced higher relative abundance of Clostridiaceae XIVa, Clostridiaceae XIVb and Lachnospiraceae. Besides, MIX group showed lower abundance of pathogenic bacteria such as Campylobacter. Metabolome analysis showed that all the 3 treatment groups (XOS, BBC and MIX) showed lower concentrations of sorbitol and both XOS and BBC group had higher concentrations of pyridoxine levels than CT group. Besides, XOS and BBC groups enhanced the content of hydroxyphenyl derivatives 4-hydroxyphenylpyruvate 1 and 3-(3-hydroxyphenyl) propionic acid, respectively (P < 0.05). Notably, MIX group enhanced both 4-hydroxyphenylpyruvate 1 and 3-(3-hydroxyphenyl) propionic acid (P < 0.05). Thus, XOS and BBC may have a synergistic role to improve the performance of broilers by modulating gut microbiota and metabolome.

Discovery and validation of novel protein markers in mucosa of portal hypertensive gastropathy

Background

Portal hypertension induced esophageal and gastric variceal bleeding is the main cause of death among patients of decompensated liver cirrhosis. Therefore, a standardized, biomarker-based test, to make an early-stage non-invasive risk assessment of portal hypertension, is highly desirable. However, no fit-for-purpose biomarkers have yet been identified.

Methods

We conducted a pilot study consisting of 5 portal hypertensive gastropathy (PHG) patients and 5 normal controls, sampling the gastric mucosa of normal controls and PHG patients before and after endoscopic cyanoacrylate injection, using label-free quantitative (LFQ) mass spectrometry, to identify potential biomarker candidates in gastric mucosa from PHG patients and normal controls. Then we further used parallel reaction monitoring (PRM) to verify the abundance of the targeted protein.

Results

LFQ analyses identified 423 significantly differentially expressed proteins. 17 proteins that significantly elevated in the gastric mucosa of PHG patients were further validated using PRM.

Conclusions

This is the first application of an LFQ-PRM workflow to identify and validate PHG–specific biomarkers in patient gastric mucosa samples. Our findings lay the foundation for comprehending the molecular mechanisms of PHG pathogenesis, and provide potential applications for useful biomarkers in early diagnosis and treatment.

Trial registration and ethics approval: Trial registration was completed (ChiCTR2000029840) on February 25, 2020. Ethics Approvals were completed on July 17, 2017 (NYSZYYEC20180003) and February 15, 2020 (NYSZYYEC20200005).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01787-5.

Effect of 2-hydroxy-4-(methylthio) butanoic acid and acidifier on the performance, chyme pH, and microbiota of broilers

This study was aimed to explore the comparative acidifying properties of 2-hydroxy-4-(methylthio) butanoic acid (HMTBA) and a combination of DL-methionine (DLM) and acidifier in male broiler production. A total of 480 1-day-old broiler chicks were randomly divided into four treatments: A (low HMTBA, 0.057% HMTBA); B (low acidifier, 0.05% DLM + 0.057% acidifier); C (high HMTBA, 0.284% HMTBA); and D (high acidifier, 0.25% DLM + 0.284% acidifier). At 21 d, growth performance, chyme pH, digestive enzyme activities, and intestinal microflora were measured. The pH of crop, gizzard, and ileum contents was higher in the HMTBA treatment group than in DLM + acidifier treatment group. Furthermore, acidifier supplementation promoted growth of butyrate-producing bacteria such as Faecalibacterium, whereas high HMTBA (0.284%) inhibited the proliferation of acid-producing bacteria including Roseburia and Collinsella. The chymotrypsin activity was lower in the HMTBA group than in the DLM + acidifier group. In contrast, high-level HMTBA group showed higher average daily gain and average daily feed intake than the DLM + acidifier group. These results suggested that HMTBA work through different pathways with DLM plus acidifier.

Assessment of Stocking Rate and Housing System on Performance, Carcass Traits, Blood Indices, and Meat Quality of French Pekin Ducks

Commercial practice in poultry production management has been susceptible to increased problems, driven by concerns about safety of food and animal welfare. Thus, the main proposal of the present study was to evaluate the influence of different stocking densities on performance, blood, and carcass traits of Pekin ducklings reared on two different floor types (wood shaving litter, WSL or plastic slatted floor, PLS). A total of 450 one-day-old ducklings were randomly allocated into six equal experimental groups stocking density (nine, 15 and 21 birds/m2 during the first 14 d and three, five and seven birds/m2 until 49 days) reared on two floor types (WSL and PLS), five replicate pens each. Increased stocking density reduced body weight (BW), weight gain (WG), and feed conversion ratio (FCR) values and increased feed intake (FI) in both floor types at 14 days old. At 49 days old, reared ducklings on PLS type verified higher BW and WG and reduced FCR values. Moreover, increasing stocking density in both floor types significantly reduced the breast, thigh, and left fillet percentages. Conversely, reared birds floored on PLS system decreased the triglycerides (TG) and increased the total cholesterol (TC) serum content. Furthermore, the meat contents of TG and TC were decreased in birds reared on higher stocking density but not affected by floor type. Further, serum antioxidant indices were reduced in PLS birds on low stocking densities. In conclusion, housing Pekin ducklings on PLS improved their growth performance, carcass traits, meat cholesterol, and antioxidant status, particularly at stocking density of three and five birds/m2.

Effects of nicotinamide and sodium butyrate on meat quality and muscle ubiquitination degradation genes in broilers reared at a high stocking density

This study was conducted to investigate the effects of supplementation with nicotinamide (NAM) and sodium butyrate (BA) on meat quality and expression of muscle development genes in broilers reared at a high stocking density. A total of 567, 21-day-old AA broilers were randomly assigned to 5 treatment groups and 2 control groups, with 7 replicates of each group. The control groups included a low stocking density (LD; 12.9 birds/m²) and were fed a basal diet. The treatment groups were kept at a high stocking density (HD; 18.6 birds/m²) and received either a low dose of NAM (50 mg/kg; treatment LN), a high dose of NAM (100 mg/kg; treatment HN), a low dose of BA (500 mg/kg; treatment LB), a high dose of BA (1,000 mg/kg; treatment HB), or a compound supplement (50 mg/kg NAM+500 mg/kg BA; treatment COMB); broilers were reared till 42 D of age. The control groups were kept at HD or at LD (12.9 birds/m²) and were fed a basal diet. The heterophil-to-lymphocyte ratio was significantly higher in the HD control group than that in the LD group; this ratio was significantly lower in treatments LN, HN, HB, and COMB than that in the HD control group. The lightness of breast muscles at 45 min and 24 h after slaughter was significantly higher in the HD group than that in the LD group, and the HD group showed the highest drip loss at 24 h and 48 h. Lightness and drip loss were lower in the HN, LB, and COMB treatments than those in the HD group. HD rearing significantly reduced gene expression of myogenic regulatory factor 5 (MYF5) while significantly increased expression of the protein ubiquitin degradation genes FBXO9, FBXO22, and FBXO32. All treatments significantly reduced FBXO9 and FBXO32 expression. Our results suggest dietary supplementation with NAM and BA can improve meat quality of broilers under high stocking density by upregulating the expression of myogenic genes, and inhibiting protein ubiquitination.

Microbiota, Gut Health and Chicken Productivity: What Is the Connection?

Gut microbiota and its relationship to animal health and productivity in commercial broiler chickens has been difficult to establish due to high variability between flocks, which derives from plenty of environmental, nutritional, and host factors that influence the load of commensal and pathogenic microbes surrounding birds during their growth cycle in the farms. Chicken gut microbiota plays a key role in the maintenance of intestinal health through its ability to modulate host physiological functions required to maintain intestinal homeostasis, mainly through competitive exclusion of detrimental microorganisms and pathogens, preventing colonization and therefore decreasing the expense of energy that birds normally invest in keeping the immune system active against these pathogens. Therefore, a “healthy” intestinal microbiota implies energy saving for the host which translates into an improvement in productive performance of the birds. This review compiles information about the main factors that shape the process of gut microbiota acquisition and maturation, their interactions with chicken immune homeostasis, and the outcome of these interactions on intestinal health and productivity.