Duck Intestine Research Articles

In vitro probiotic potential of lactic acid bacteria isolated from the intestines of Muscovy ducks.

The current study was conducted to isolate, test and characterize molecularly and physiologically lactic acid bacteria from the intestines of Muscovy ducks to evaluate their probiotic potential for poultry farming. Three hundred lactic acid bacteria from the gastrointestinal tract of Muscovy ducks were isolated. The strains were phenotypically characterized by observing cell morphology, performing Gram staining, catalase production, and testing their ability to grow in MRS broth at different temperatures, pH values, NaCl concentrations, bile concentration, and in compatibility tests between strains. Nine strains were selected based on their resilience. Eight strains were identified using molecular techniques. These strains exhibited significant tolerance to acidic pH, bile salts, and NaCl, essential for probiotic function. All isolates inhibited the growth of Salmonella enterica serotype Typhimurium (DT104) and Enteropathogenic Escherichia coli serotype O86:H34 (EPEC), showcasing their antimicrobial potential. Antibiotic susceptibility testing revealed 100% resistance to clindamycin and erythromycin but high susceptibility to ampicillin and vancomycin. Growth was observed at various temperatures, indicating mesophilic characteristics. Compatibility tests confirmed their suitability for probiotic formulations. Genomic analysis identified the strains primarily as Enterococcus. Conclusively, the study identified eight out of nine selected lactic acid bacteria strains from Muscovy ducks as autochthonous probiotics, showing resilience to treatments and compatibility for consortium formulation. These strains are suitable for in vivo testing for potential poultry farming applications. Further research on their molecular mechanisms and in vivo effects is needed.

Bone lesions and intestinal barrier disruption caused by the isolated novel goose parvovirus infection in ducks

Short beak and dwarfism syndrome (SBDS) is attributed to Novel Goose Parvovirus (NGPV), which has inflicted significant economic losses on farming in China. Despite its significant impact, limited research has been conducted on the pathogenesis of this disease. The SD strain, a parvovirus variant isolated from ducks in Shandong province, was identified and characterized in our study. Phylogenetic analysis and sequence comparisons confirmed the classification of the SD strain as a member of NGPV. Based on this information, we established an animal model of SBDS by inoculating Cherry Valley ducks with the SD strain. Our findings indicate that infection with the SD strain leads to a reduction in body weight, beak length, width, and tibia length. Notably, significant histopathological alterations were observed in the thymus, spleen, and intestine of the infected ducks. Furthermore, the SD strain induces bone disorders and inflammatory responses. To evaluate the impact of NGPV on intestinal homeostasis, we performed 16S rDNA sequencing and gas chromatography to analyze the composition of intestinal flora and levels of short-chain fatty acids (SCFAs) in the cecal contents. Our findings revealed that SD strain infection induces dysbiosis in cecal microbial and a decrease in SCFAs production. Subsequent analysis revealed a significant correlation between bacterial genera and the clinical symptoms in NGPV SD infected ducks. Our research providing novel insights into clinical pathology of NGPV in ducks and providing a foundation for the research of NGPV treatment targeting gut microbiota.

Research Note: Synergistic effect of isopropoxy benzene guanidine and colistin against mcr-1-positive Escherichia coli in vitro and in duck intestine infection models

Colistin (CST) is considered as "agent of last resort" against gram-negative bacteria as feed additive. Its clinical effectiveness has reduced since the emergence of mcr-1 gene in ducks. Isopropoxy benzene guanidine (IBG), a new guanidine derivative, showed positive effects on improving animal weights and alleviating intestinal pathogens, therefore, the objective of this study was to evaluate the effect of this compound supplement with CST in ducks and explore the possibilities in feed additive. A total of fifteen duck-origin Escherichia coli carrying the mcr-1 gene were included in this study. A checkerboard microdilution assay was used to evaluate the in vitro antibacterial activity of IBG combined with CST against mcr-1-positive E. coli. A 3-by-2 time-kill array of IBG (16, 32, and 64 μg/mL) and CST (1/2 MIC and 1/4 MIC) over 24 hours was utilized to characterize the activity of the agents alone and in combination against E. coli strain 1 in vitro. The intestinal colonization model was used to evaluate the in vivo effect of IBG combined with CST. These results indicated that the combination of IBG plus CST showed a synergistic effect against all clinical isolates (FICI < 0.5). The bacterial burden was reduced by more than 2 log10 CFU/mL when E. coli strain 1 was tested with 1/2 MIC CST plus 64 μg/mL IBG for 24 h. Further experiments in vivo demonstrated that the CST combined with IBG was able to increase duck weights, reduced intestinal pathogenic E. coli and showed a synergistic antibacterial effect. Combination of CST (4 mg/kg b.w.) plus IBG (32 or 64 mg/kg b.w.) achieved 1.84 to 3.29 log10 CFU/g killing after 7 d of therapy, which was significantly different from that in the challenge control group (p<0.05). In summary, our study demonstrated the potential use of IBG as feed additive for veterinary purposes in ducks and provided new insights into overcoming resistance in the future.

Temporal variation in production performance, biochemical and oxidative stress markers, and gut microbiota in Pekin ducks during the late growth stage

In the late growth stage of commercial Pekin ducks, a significant increase in feed intake and a decline in body weight gain have been observed, leading to impaired feed conversion efficiency. To address this issue, we investigated alterations in production performance, blood biochemical indices, ileum tissue architecture, and microbial community structure in Pekin ducks. The primary objective was to provide robust data supporting the improvement of meat duck production efficiency during the late growth stage (28-42-days-old). Forty 28-day-old Pekin ducks were randomly assigned to 8 replicates, with five ducks per replicate. The rearing period lasted 14 days, with feed and water provided ad libitum. Our findings indicated a significant increase in Pekin duck body and heart weights with advancing age (P < 0.05). Moreover, serum antioxidant enzyme and high-density lipoprotein concentrations significantly increased, whereas triglyceride levels decreased (P < 0.05). Notably, the height of the ileal villi was significantly reduced (P < 0.05). The microbial community structure of the ileum exhibited significant changes as ducks aged, accompanied by a substantial increase in microbial flora diversity, particularly with the formation of more tightly connected microbial network modules. Time-dependent enrichment was observed in microbial gene functions related to energy metabolism pathways. At the genus level, Sphingomonas and Subdoligranulum have emerged as crucial players in microbial differential functional pathways and network formation. These bacteria likely serve as the key driving factors in the dynamic microbial changes that occur in Pekin ducks over time. Overall, our findings suggest a potential decline in the absorption function of the small intestine and fat deposition performance of Pekin ducks during later growth stages, which may be attributed to the maturation and proliferation of the gut microbial community.

Duck compound probiotics fermented diet alters the growth performance by shaping the gut morphology, microbiota and metabolism

Dietary absorption and digestion are influenced by the microbiota, morphology, and digestive enzymes of intestines, and fermentation is a popular and effective technique to enhance animal rearing growth performance. This study aims to explore the pivotal role of Muscovy duck probiotics fermented feedstuff (FF) in altering the growth performance by reshaping gut morphology, microorganisms and metabolism. The findings showed that FF considerably raised the levels of fatty acids (FA) and small peptides (7-19AA) in the diet. Further feeding trial data reveals that FF greatly increased the Muscovy duck average daily gain (ADG) but had no effect on their daily feed intake (DFI), and the FCR significantly dropped (P < 0.05). Additionally, it was evident that FF improved the integrity of the intestinal mucosa in Muscovy duck by increasing villus height, villus height-to-crypt depth ratio, and lowering crypt depth. Then, in comparison to the control group (NC), there was a significant increase in the gene expression of the mucosal tight junction proteins Occludin, Claudin-1, and Zo-1 in the intestine of Muscovy duck. Additionally, there was higher expression of the mucosal transport channels SGLT-1, PepT1, AQP2, AQP3, and AQP10 in the similarly colon site, jejunum, and duodenum. Furthermore, in AB-PAS/PAS-stained duodenum, jejunum, ileum, and similarly colon site, FF markedly increased relative mucus output and goblet cells while decreasing epithelial cell apoptosis. Following 16S sequencing data indicated that the intestinal microbiota was altered and the diversity and richness of gut microbes was greatly enhanced by FF. Particularly, the boost of core probiotics, such as Rothia of duodenum, Limosilactobacillus and Lentilactobacillus of jejunum, Lactococcus and Rothia of ileum, Ligilactobacillus and Entocuccus of similarly colon site, Gallibacterium of caecum. And reduced potentially pathogenic bacteria (Campylobacter, Prevotellaceae, Clostridia-vadinBB60, and Oscillospira). Nontargeted metabolomics assay for intestinal content confirmed an increased organic acids (oxidanesulfonic acid, cholic acid, gallic acid, coumaric acid, pipecollc acid, 13s-hydroxyoctadecadienoic acid) and glycosides metabolites (5-hydroxydantrolene, 3-hydroxyguanfacine glucuronide, acetylleucine, astragalin, xanthosine, taxiphylin, sinapine, denudatine, penylalanyl-tyrosine and phenylalanyl-valine). These findings demonstrated that FF, a viable option to improve Muscovy duck growth performance through reconstructed intestinal morphology, microorganisms, and metabolism, subsequently promoted the gut health and increased diet digestion and absorption. The study that is being presented offers scientific proof that FF might be a useful strategy for improving Muscovy duck growth performance.

MiR-106a-5p by Targeting MAP3K2 Promotes Repair of Oxidative Stress Damage to the Intestinal Barrier in Prelaying Ducks.

Under caged stress conditions, severe disruptions in duck intestinal barrier function, which adversely affect economic performance, have been observed. MiRNAs play a crucial role in cellular processes, but the mechanisms underlying their involvement in repairing oxidative stress-induced damage to duck intestinal barriers have not been elucidated. We performed miRNA-seq and protein tandem mass tagging (TMT) sequencing and identified differentially expressed miRNAs and proteins in oxidative stress-treated ducks. Dual-luciferase reporter vector experiments, RT-qPCR, and Western blotting revealed the regulatory role of apla-miR-106a-5p/MAP3K2 in intestinal barrier damage repair. The results showed that oxidative stress led to shortened villi and deepened crypts, impairing intestinal immune function. Significant downregulation of apla-miR-106a-5p was revealed by miRNA-seq, and the inhibition of its expression not only enhanced cell viability but also improved intestinal barrier function. TMT protein sequencing revealed MAP3K2 upregulation in caged-stressed duck intestines, and software analysis confirmed MAP3K2 as the target gene of apla-miR-106a-5p. Dual-fluorescence reporter gene experiments demonstrated direct targeting of MAP3K2 by apla-miR-106a-5p. RT-qPCR showed no effect on MAP3K2 expression, while Western blot analysis indicated that MAP3K2 protein expression was suppressed. In summary, apla-miR-106a-5p targets MAP3K2, regulating gene expression at the transcriptional level and facilitating effective repair of intestinal barrier damage. This discovery provides new insights into the molecular mechanisms of physiological damage in ducks under caged stress, offering valuable guidance for related research.

HISTOMORPHOMETRY OF SMALL INTESTINE OF BALI DUCKS AT DIFFERENT AGES

Bali ducks are one of the local poultry breeds that have high potential as producers of meat and eggs. The existence of this Balinese duck is spread evenly in rural areas in Bali. This study aims to histomorphometry of the small intestine of Bali ducks at different ages. In this study, 18 male Bali ducks were used as small intestine samples at 1 month, 3 months and 5 months. Bali ducks were obtained from a duck farm in Mengwi District, Badung Regency, Bali Province. Sampling of the small intestine was carried out in three parts, namely the duodenum, jejunum and ileum, then the organs were fixed with NBF 10% which was then made into histological preparations with HE staining. The research results are presented in a quantitative descriptive form. The results showed that the histological structure of the small intestine, namely the duodenum, jejunum and ileum, is composed of four layers, namely the tunica mucosa, tunica submucosa, tunica muscularis and the outermost is tunica serosa. The histomorphometric results, namely the total thickness of the layers that make up the small intestine of Bali ducks aged 1, 3, and 5 months respectively were 180.39 ± 29.59µm; 170.35±32.91µm; 302.09±78.94µm. It can be concluded that the histomorphometry of the small intestine of Bali ducks in ducks aged 1, 3, and 5 months has differences of thickness.

Clinico-pathological assessment of virulent Newcastle Disease Virus in ducks.

Newcastle disease (ND) is an infectious, highly contagious and lethal disease of avian species. It is considered that ducks are natural reservoir or carrier for Newcastle disease virus (NDV) and are resistant against different strains of NDV. Current study was designed to evaluate the pathogenesis of Newcastle disease in domestic ducks through histopathology, immunohistochemistry (IHC) and serum biochemical changes. For this purpose, eighty ducks were reared for 42 days and divided in two groups A and B. Ducks in group A were challenged with (NDV) at rate of 0.1 ml of ELD50 (virus titer 107.32/100µl) on second week of age, whereas Group B was control negative. Splenomegaly, atrophy of thymus and necrotic lesion in kidney were observed on 9th day of post infection. Hepatic degeneration and mononuclear cell infiltration were noticed in proventriculus and intestine in challenged ducks. Viral antigen detected in lungs, intestine, proventriculus and lymphoid organs of infected ducks through IHC. Albumin and total protein values were significantly low in infected groups A as compared to control group B. ALT, AST, and ALP values were significantly high in infected group A. On 5th and 7th day of post infection oropharyngeal swabs were negative for NDV and cloacal swabs were positive for NDV through Reverse transcriptase polymerase chain reaction. It is concluded that ducks are susceptible to NDV and virulent strain of NDV caused disease in ducks.

Degradation of deoxynivalenol by a microbial consortia C1 from duck intestine.

Deoxynivalenol (DON), one of the most widespread mycotoxins in food and feed, poses a persistent health threat to humans and farm animals, and is difficult to eliminate. The utilization of the biotransformation mechanism by microorganisms to detoxify DON is a promising strategy. Although individual strains are capable of DON degradation, their isolation and purification are challenging and time-consuming. Recently, the microbial consortia concept has been proposed, owing to their ability to perform more complex tasks and are more tolerant to environmental changes than individual strains or species. In this study, the novel microbial consortia C1 that could efficiently convert DON to de-epoxy DON (DOM-1) was screened from the cecum contents of ducks. After 24h anaerobic incubation, 100μg/ml DON was completely degraded by C1. In vitro, C1 can effectively degrade DON in corn steep liquor (CSL) with an efficiency of 49.44% within 14days. Furthermore, C1 effectively alleviated the DON poisoning in mice. After C1 treatment, the serum DON level decreased by 40.39%, and the reduction in serum total protein and albumin levels were mitigated. Additionally, C1 is effective in protecting the mouse liver against 5mg/kg DON. These findings suggest that C1 could be a promising DON biological detoxifier and provide novel microbial resources for preventing DON contamination.

Morphogenesis of immune formations of ducks' intestine

The morphogenesis of immune formations of duck intestines was studied. Material for histological studies was taken from Blagovarsky cross broiler ducks aged from one to 420 days. The obtained sections were stained with Karatsi's hematoxylin and eosin – to establish the features of the microscopic structure of intestinal immune formations, Weigert's hematoxylin and picrofuchsin according to Van Gieson and aniline blue in combination with acid fuchsin and Orange G according to Mallory – to identify collagen fibers, resorcin-fuchsin according to Weigert – for differentiation of elastic fibers. To determine reticular fibers, sections were impregnated with 1–2 % argentum nitrate solution according to the modified Kelemen method. Electron microscopy studies were carried out to study the ultrastructure of the immune formations of the intestines of 180-day-old ducks. The studies have established that the intestinal wall in the places where immune formations of the intestines in ducks are localized is formed by tunica mucosa, tunica muscularis and tunica serosa, the area of which in all immune formations changes unevenly and asynchronously with the birds’ age. The tunica mucosa occupies the largest area, which changes unevenly and asynchronously, reaching maximum values (from 71.66 ± 0.25 to 81.28 ± 0.19 %) during the first 25 days of the ducks' life. The tunica muscularis occupies a smaller area than the tunica mucosa. It decreases unevenly in the first 25 days of a bird’s life, and in older birds it increases and reaches maximum values (35.68 ± 0.49–46.67 ± 1.39 %) in 330- and 420-day-old birds. The tunica serosa occupies the smallest area. In day-old birds, this indicator is the highest (from 2.47 ± 0.07 to 6.20 ± 0.02 %) and decreases with age by 1.24–6.52 times. Lymphoid tissue, which determines the functions of immune formations, is located in their tunica mucosa and tunica muscularis. It is detected in the tunica mucosa of all immune formations and the tunica muscularis of caecal diverticula from the bird’s one-day age, in the tunica muscularis of other immune structures – from the age of 10–20 days. The total area of lymphoid tissue increases from one day (27.03 ± 0.88–31.72 ± 0.04 %) to 150 days of age in ducks in Peyer's patches of the duodenum and jejunum and cecal diverticula (59.86 %, 59.58 ± 1.28, 65.12 ± 0.50 %), up to 210 days of age in Peyer’s patches of the ileum (71.64 ± 1.03 %), up to 330 days of age in Peyer’s patches of the cecum (37.84 ± 5.12 %), up to 420 days of age in Meckel’s diverticulum (55.24 ± 0.37 %). In older birds, the area of lymphoid tissue decreases, which indicates the beginning of its involution and, accordingly, the involution of immune formations.

Combined effects of microplastics and chlortetracycline on the intestinal barrier, gut microbiota, and antibiotic resistome of Muscovy ducks (Cairina moschata)

Antibiotics and microplastics (MPs) have become critical concerns worldwide because of their increasing amount and ecological risks to ecosystems. However, how MPs exposure affects the bioaccumulation and risks of antibiotics in waterfowls remains poorly understood. In this study, Muscovy ducks were exposed to single and combined contamination with polystyrene MPs and chlortetracycline (CTC) for 56 days, and the effects of MPs on CTC bioaccumulation and their risks in duck intestines were investigated. MPs exposure reduced the bioaccumulation of CTC in the intestine and liver of ducks and increased their fecal CTC excretion. MPs exposure caused severe oxidative stress, inflammatory response, and intestinal barrier damages. Microbiome analysis showed that MPs exposure induced microbiota dysbiosis by increasing the abundance of Streptococcus and Helicobacter, the increase of which may exacerbate intestinal damages. Co-exposure to MPs and CTC alleviated the intestinal damage by regulating the gut microbiome. Metagenomic sequencing revealed that the combined exposure to MPs and CTC increased the abundance of Prevotella, Faecalibacterium, and Megamonas and incidence of total antibiotic resistance genes (ARGs), especially tetracycline ARGs subtypes in the gut microbiota. The results obtained herein provide new insights into the potential risks of polystyrene MPs and antibiotics in waterfowls living in aquatic environments.

Characterization of microbiota and secretory Ig-A in the domestic duck (Anas platyrhynchos) small and large intestine

Abstract. Susanti R, Utami NR, Yuniastuti A. 2023. Characterization of microbiota and secretory Ig-A in the domestic duck (Anas platyrhynchos)small and large intestine. Biodiversitas 24: 2458-2466. The Microbiome composition could affect the duck's intestines' microenvironment, which may shape the microstructure's anatomy, metabolism, and immune system. Therefore, this study aims to characterize the intestinal microbiome's abundance, diversity, and IgA distribution in ducks' intestines. This study took 15 healthy domestic ducks (Anas platyrhynchosLinnaeus, 1758) from an intensive duck farm in Central Java, Indonesia. Five grams of each small and large intestine content were collected aseptically for metagenomic analysis. Then, the intestine organs were taken for immunohistochemistry preparations to depict the IgA distribution. The results showed that the small intestine has a greater bacterial abundance community, with 18 phyla, while only 13 are found in the large intestine. Interestingly, three phyla: Firmicutes, Actinobacteria, and Bacteroidetes, were found dominantly in both organs. However, the comparison of Firmicutes and Bacteroidetes ratio was higher in the small intestine (2357.76) than large intestine (10.64). The IgA distribution in the small and large intestines showed intermediate staining intensity (score: 2.07-2.20) and a final Allred score of 5.0 (positive). Even though dysbiosis microbiome was present in intestines with dominant species Streptococcus and Enterococcus, it seems no significant IgA over secretion. Understanding duck's gut immune response is important because it is highly tolerant to the pathogens that make them play an important role as an environmental reservoir for pathogenic viruses and bacteria and may potentially comprehend future infectious disease outbreaks.

Effect of Moringa leaves fermented by probiotics (Saccharomyces spp.) on abdominal fat and pathogenic bacteria in the intestines of ducks

The use of probiotics in feed is expected to have a synergistic effect with phytochemicals in herbal leaves (Moringa leaves), so that it can improve the growth and health of ducks. The purpose of this study was to examine the effect of the inclusion of fermented Moringa oleifera leaf powder (FM) by probiotics, on growth and pathogenic bacteria in the jejunum of ducks. A total of 240 male ducks (Anas sp.) aged 2 weeks were randomized into 4 treatment groups with an FM-added diet, namely: 2% (B); 4% FM (C), and 6% FM (D), respectively. Feed without the addition of FM as a control (A). Each treatment was repeated 6 times with 40 ducks. The results, the final body weight (BW), live weight gain (LWG) and feed efficiency (FE) in group B, C, and D ducks were significantly (P≤0.05) higher than group A ducks. In contrast, abdominal fat, the number of Coliform bacteria and E. coli in group B, C, and D ducks, significantly (P≤0.05) lower than control (A). It was concluded that giving 2-6% FM in feed can increase growth and feed efficiency, and conversely, by reducing abdominal fat and pathogenic bacteria in the intestine of ducks.

Effect of Moringa leaves fermented by probiotics (Saccharomyces spp.) on abdominal fat and pathogenic bacteria in the intestines of ducks

Effect of Moringa leaves fermented by probiotics (Saccharomyces spp.) on abdominal fat and pathogenic bacteria in the intestines of ducks

Effect of different levels of oxytetracycline antibiotics on some intestine and immune traits of Chinese ducks

This study was conducted in the field of poultry, Agricultural Research and Experiments Station, College of Agriculture, Al-Muthanna University, from 14/12/2021 to 14/2/2022. A total of Sixty one-day-old Peking ducks were reared, with an average weight of 42 g, to study the effect of adding different levels of oxytetracycline antibiotics at levels: 0, 0.125, 0.250 and T4 0.375% on some intestinal and immune traits of Chinese ducks. The results indicated a significant superiority remove on the relative weight and length of the small intestine with all its parts (duodenum, jejunum and ileum) for Chinese ducks when using the antibiotic oxytetracycline antibiotics, it was described as a growth stimulator compared to the control treatment. The addition of the antibiotic oxytetracycline antibiotics at high levels (0.375 mg/kg feed) led to a significant improvement remove of the immunological characteristics represented by the relative weight of bursa gland compared to the control treatment

Lectin Staining to Detect Human and Avian Influenza Virus Receptors in the Airway of Nonhuman Primates.

Hemagglutinin (HA) on the surface of influenza viruses binds to sialic acids, mainly N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid. Neu5Ac and N-glycolylneuraminic acid lie at the terminal end of sugar chains on the cell surface. Human influenza viruses preferentially bind to sialic acids bound to galactose by the alpha2-6 linkage (Neu5Acα2-6Gal), abundant in the human airway. In contrast, avian influenza viruses preferentially bind to Neu5Acα2-3Gal, abundant in the intestine of ducks. Sambucus nigra lectin (SNA) and Maackia amurensis lectin (MAA) bind to Neu5Acα2-6Gal and Neu5Acα2-3Gal, respectively. These two lectins have therefore been applied to detect sialic acids on the airway epithelium of animals.

Gross, Histomorphological and Scanning Electronic Microscopic Studies on Gut Associated Lymphoid Tissue of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

Background: The study on Gut Associated Lymphoid Tissue (GALT) of Pati duck of Assam is of great value in regard to normal academic and bio-medical research aspects. The aim of the study was to evaluate the gross, histomorphological and scanning electronic microscopic examination of gut-associated lymphoid tissue of the intestine of Pati duck at different age group. Methods: For this study, forty five Pati ducks were divided into five groups depending on its age viz., 1st week, 4th week, 16th week, 24th week and 42nd weeks old. The pieces of gut having lymphoid tissue or Peyer’s patches were collected immediately after slaughter. These samples were fixed in 10% neutral buffered formalin solution and were processed as per the standard technique of procedure (Luna, 1968). The paraffin blocks were sectioned in Shandon Finesse microtome at 5 µm thickness and the sections were stained with Mayer’s Haematoxylin and Eosin staining technique for Cellular details, Van Gieson’s method for collagen fibres, Gomori’s method for reticular fibres, Hart’s method for elastic fibres and Bielchowsky’s method for axis cylinder and dendrites as per the method of Luna (1968). Result: Gut-associated lymphoid tissue was found in the duodenum, jejunum, ileum, caecum and the terminal part of the rectum in all the age group of Pati duck. The lymphoid compartment of the gut-associated lymphoid tissue in duck included a follicular structure, dome, follicle associated epithelia and interfollicular area. Lamina propria of jejunum was heavily infiltrated with diffuse lymphatic tissue in the 16th, 24th and 42nd week of age of Pati duck. The scattered and diffuse lymphatic infiltration occurred in all age groups. The lamina propria of the colorectum revealed an extensive network of reticular fibre with diffused lymphatic tissue in all the age group of duck. In Scanning Electron Microscope, the lumen of the jejunum was covered by finger-like villi with numerous opening of goblet cells. The lymphoid follicle of Lamina propria contains numerous lymphocytes along with connective tissue fibres.

Histochemical Studies on Post Natal Development of Gut Associated Lymphoid Tissue (GALT) of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

Background: The Pati duck constitutes a major indigenous duck variety in the state of Assam. The study of the gut associated lymphoid tissue (GALT) of Pati duck of Assam is of great value in regard to normal academic and bio-medical research aspects. It is also pre-requisite for correct diagnosis and evaluating the treatment of certain diseases like duck virus enteritis, duck cholera, aflatoxicosis, botulism etc, caused by different types of pathogens, food poisoning and food allergy. Methods: The study was conducted on Pati duck of Assam in where 45 numbers of ducks were selected by irrespective of sex at different stages of development. The birds were divided into five groups depending on its age viz., 1st week, 4th week, 16th week, 24th week and 42nd weeks old. The pieces of gut having lymphoid tissue or Peyer’s patches were collected immediately after slaughter. Samples were made cryosections (-20oC) at 10µm in thickness and were temporally stored at (-22oC). The histochemical staining was done after that. Result: The acid phosphatase activity was weak in the lymphoid follicles of 1st and 4th week of age of Pati duck, while its activity was moderate in 16th, 24th and 42th week of age.The alkaline phosphatase activity was moderate reaction in the lymphoid follicles of 1st and 4th week of age of Pati duck, while its activity was intense in 16th, 24th and 42th week of age of duck. The lymphoid follicles of both Peyer’s patches and solitary lymphoid nodules were showed moderate activity for adenosine tri-phosphatase activity in 1st and 4th week old Pati duck and strong activity in 16th, 24th and 42th week of age of Pati duck, respectively. The lymphoid nodules of intestine showed strong reaction for non-specific esterase activity in all the age groups of Pati duck.

Accumulation of heavy metals in ducks exposed to heavy metals-contaminated water

The objective of this study was to determine the bioaccumulation of heavy metals (HM) (Cu, Zn, Hg, Pb and Cd) in 15 tissues (brain, breast muscle, sternum, thigh muscle, femur, blood, heart, lung, gizzard, liver, intestine, spleen, pancreas, bile and kidney) of domestic ducks exposed to HM-contaminated water with levels equal to values specified in the column B of QCVN 40:2011/BTNMT. The experiment was a completely randomized design with two treatments: without exposure to HM (CT) and with exposure to HM (ET). Each treatment was replicated 3 times. Ducks were randomly allocated to the treatments with a stocking density of 10 ducks per cage and reared for 8 weeks. The results showed that concentrations of HM, particularly toxic metals such as Hg, Pb and Cd, in all tissues of duck in the CT were lower than those in the ET. The highest levels of HM in tissues were found in the liver and kidney. In the ET, Pb levels in kidney and bone and Cd levels in liver and kidney exceeded the permissible exposure limit according to the guidance of the Ministry of Health of Vietnam and the European Commission. This study demonstrated that the accumulation of HM in duck tissues could happen even though ducks were exposed to relatively low concentrations of HM in water. Thus, further investigation on the bioaccumulation of HM in farmed ducks as well as wild water-birds should be conducted in the near future.

Arsenic exposure induces intestinal barrier damage and consequent activation of gut-liver axis leading to inflammation and pyroptosis of liver in ducks

Arsenic is an important hazardous metalloid commonly found in polluted soil, rivers and groundwater. However, few studies exist regarding the effect of arsenic trioxide (ATO) on the gut-liver axis and consequent hepatotoxicity in waterfowl. Here, we investigated the influence of ATO on duck intestines and livers, and explored the role of the gut-liver axis in ATO-induced hepatotoxicity and intestinal toxicity. Our results demonstrated that ATO-exposure induced intestinal damage, liver inflammatory cell infiltration and vesicle steatosis. Additionally, the intestinal microbiota community in ATO-exposed ducks displayed significantly decreased α-diversity and an altered bacterial composition. Moreover, ATO-exposure markedly reduced the expression of intestinal barrier-related proteins (Claudin-1, MUC2, ZO-1 and Occludin), resulting in increased intestinal permeability and elevated lipopolysaccharide levels. Simultaneously, ATO-exposure also upregulated pyroptosis-related index levels in the liver and jejunum, and increased pro-inflammatory cytokine production (IFN-γ, TNF-α, IL-18, and IL-1β). Our further mechanistic studies showed that ATO-induced liver and jejunum inflammation were provoked by the activation of the LPS/TLR4/NF-κB signaling pathway and NLRP3 inflammasome. In summary, these results manifested that ATO exposure can cause liver and jejunal inflammation and pyroptosis, and the indirect gut-liver axis pathway may play an essential role in the potential mechanism of ATO-induced hepatotoxicity.