Effects of Microbial Aerosol in Poultry House on Meat Ducks' Immune Function

Growth Performance of and Liver Function in Heat-Stressed Magang Geese Fed the Antioxidant Zinc Ascorbate and Its Potential Mechanism of Action

The aim of this study was to investigate the in vitro antioxidant activity of zinc ascorbate (AsA-Zn), its effects on the growth performance of and liver function in Magang geese under heat stress, and its potential mechanism. At AsA-Zn concentrations of 7.5, 15, 30, and 60 µmol/L, the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) radical scavenging rate increased significantly by 120.85%, 53.43%, 36.12%, and 0.99%, respectively, compared with that of ascorbic acid (AsA), indicating that AsA-Zn had better antioxidant performance in vitro. In this study, Magang geese were divided into a control group (basal diet, CON) and experimental groups, who received the basal diet supplemented with 400 mg/kg AsA or 30 (AsA-Zn30), 60 (AsA-Zn60), or 90 (AsA-Zn90) mg/kg AsA-Zn. AsA-Zn supplementation considerably reduced the feed-to-gain ratio, whereas both AsA and AsA-Zn significantly increased the thymus index. Moreover, AsA-Zn supplementation improved serum protein levels, lipid metabolism, liver function, and antioxidant capacity while reducing hepatocyte vacuolar degeneration. Furthermore, supplementation with AsA-Zn60 significantly increased the total antioxidant capacity, glutathione peroxidase activity, and superoxide dismutase activity and decreased the malondialdehyde content in the serum, liver, and hepatic mitochondria (P < 0.05), with more pronounced effects in the AsA-Zn60 group. Moreover, supplementation with ASA-Zn regulated the Nrf 2 signaling pathway and significantly increased the expression of genes encoding antioxidant-related factors in the liver. In conclusion, AsA-Zn has good antioxidant activity, and AsA-Zn supplementation may improve the antioxidant capacity of heat-stressed geese and promote their growth. Supplementation with 30 mg/kg AsA-Zn is recommended.

Bacterial and fungal aerosols in poultry houses: PM2.5 metagenomics via single-molecule real-time sequencing

Microbial aerosol contamination is a common problem in poultry farms, posing potential health risks to poultry and their caretakers. Exploring the distribution and diversity of the microbial community in poultry farm aerosols is crucial for effective mitigation strategies. The composition of bacterial and fungal aerosols is poorly understood, particularly the prevalence of potential pathogenic microorganisms in fine particulate matter (PM2.5) in various types of poultry houses. In this study, 27 PM2.5 samples were collected from 5 chicken houses and 4 duck houses in Shandong Province, China. Species-level diversity of bacterial and fungal components in PM2.5 samples was determined using advanced single-molecule real-time sequencing (SMRT) technology, based on the 16S and internal transcribed spacer 1 (ITS) ribosomal genes. Microbial diversity and community composition varied significantly across the different poultry house. Notably, duck houses had higher concentrations (p < 0.01) of PM2.5 (92.8-143.1 μg/m3) than chicken houses (42.0-56.4 μg/m3). Furthermore, microbial variation in PM2.5 samples was associated with the type of poultry facility. The predominant pathogenic microorganisms included Aspergillus sydowii, Penicillium sp., Aspergillus insolitus, Cladosporium sp., Aspergillus sp., Aspergillus pseudoglaucus, Cladosporium sp. C4092-2-PD1, and Colletotrichum sp., all of which were classified as second category of pathogens. Aspergillus sydowii and Penicillium sp. were the dominant species in chicken houses, while Cladosporium sp., Aspergillus sp., and Aspergillus pseudoglaucus were the dominant species identified in duck houses. To our knowledge, this study is the first to investigate bacterial and fungal diversity in PM2.5 samples collected from various types of poultry houses. These findings advance our understanding of poultry environmental microbiology and have important implications for safeguarding the health of both poultry and their caretakers.

Effects of Salmonella Enteritidis infection on TLRs gene expression and microbial diversity in cecum of laying hens

Salmonella Enteritidis (SE) is an important foodborne pathogen primarily causing human disease through contaminated food and water. In the current study, to assess the effect of Salmonella Enteritidis infection on the immune system and the microbial diversity of cecum and oviduct in chickens, twelve 24-week-old SE-negative White Leghorn layers were randomly selected and divided into 2 groups. Chickens in the challenge group were orally inoculated with SE, and chickens in the control group received an equal amount of sterilized Phosphate Buffered Saline solution. Serum and tissue samples (cecum, oviduct, ovary, liver, spleen, and pancreas) were collected at 7 days and 14 days post-infection (dpi). Quantitative PCR was used to detect the expression of Toll-like receptors (TLRs) in the cecum, oviduct and ovary. To understand the influence of SE infection on the microbial profile of the cecum and oviduct, microbial community composition of the cecal contents and oviducal contents were analyzed through 16S rRNA sequencing. Results showed that SE infection caused damage to the digestive organs, reproductive organs, and immune organs in laying hens. The expression of TLR1a, TLR1b, TLR2, TLR4, TLR5, TLR7 and TLR15 in the cecum were induced, and the content of IFN-γ, TNF-α, IL-2 and IL-18 in serum increased after SE infection. The composition of the microbial community significantly changed in cecal content, the dominant phylum of Firmicutes increased, and Bacteroidetes decreased significantly. In the oviduct, the microbial diversity became complicated, the dominant bacteria Faecalibacterium was significantly increased, and Bacteroides was significantly decreased. This study investigated the effects of SE infection in laying hens, including host innate immunity, the expression of TLRs, and changes in the composition of microbes in the cecum and reproductive tract. Our results may provide a scientific basis for the Salmonella Enteritidis control in chicken, the maintenance of oviduct function, and the guarantee of clean egg production.

Fungal aerosols in rabbit breeding environment: Metagenetic insight into PM2.5 based on third-generation sequencing technology

Fungal aerosols are a vital environmental hazard factor impeding the development of the rabbit breeding industry and threatening public health. This study aimed to determine fungal abundance, diversity, composition, diffusion, and variability in aerosols in rabbit breeding environments. Twenty PM_2.5 filter samples were collected from five sampling sites (i.e. En5, In, Ex5, Ex15, and Ex45) in a modern rabbit farm in Linyi City, China. Fungal component diversity at the species level was analyzed in all samples using third-generation sequencing technology. Results revealed that fungal diversity and community composition in PM_2.5 significantly differed across different sampling sites, and different pollution levels. The highest concentrations of PM_2.5 and fungal aerosols (i.e., 102.5 μg/m³ and 18.8 × 10³ CFU/m³, respectively) were found at Ex5, and these concentrations were found to decrease as the distance from the exit increased. However, no significant correlation was observed between the internal transcribed spacer (ITS) gene abundance and overall PM_2.5 levels, except for Aspergillus ruber and Alternaria eichhorniae. Although most fungi are not pathogenic to humans, zoonotic pathogenic microorganisms that cause pulmonary aspergillosis (e.g., Aspergillus ruber) and invasive fusariosis (e.g., Fusarium pseudensiforme) were observed. The relative abundance of A. ruber was higher at Ex5 than that at In, Ex15, and Ex45 (p < 0.01), and the relative abundance of the fungal species decreased with an increase in distance from the rabbit houses. Moreover, four potential novel strains of Aspergillus ruber were discovered, with 82.9%-90.3% of the nucleotide and amino acid sequences similar to those of reference strains. This study highlights the importance of rabbit environments as a source in shaping fungal aerosol microbial communities. To the best of our knowledge, this is the first study to uncover the initial characteristics of fungal biodiversity and dispersion of PM_2.5 in rabbit breeding environments, contributing to infectious disease control and prevention in rabbits.

Research progress on distribution and exposure risk of microbial aerosols in animal houses

Environmental aerosols in animal houses are closely related to the productive performance and health level of animals living in the houses. Preferable housing environments can improve animal welfare and production efficiency, so it is necessary to monitor and study these environments. In recent years, there have been many large-scale outbreaks of respiratory diseases related to biological aerosols, especially the novel coronavirus that has been sweeping the world. This has attracted much attention to the mode of aerosol transmission. With the rapid development of large-scale and intensive breeding, microbial aerosols have gradually become the main factor of environmental pollution in animal houses. They not only lead to a large-scale outbreak of infectious diseases, but they also have a certain impact on the health of animals and employees in the houses and increase the difficulty of prevention and control of animal-borne diseases. This paper reviews the distribution, harm, and control measures of microbial aerosols in animal house environments in order to improve people's understanding of them.

Ginsenoside Rg3 Ameliorates Stress of Broiler Chicks Induced by Escherichia coli Lipopolysaccharide

In broiler chicks, Escherichia coli lipopolysaccharide is a prominent cause for inflammatory damage and loss of immune homeostasis in broiler chicks. Ginsenosides have been shown to have anti-inflammatory and antioxidant effects. However, it has not been demonstrated that ginsenosides protect broiler chicks against stress induced by Escherichia coli lipopolysaccharide challenge. The aim of this is to investigate the protective effect of ginsenosides Rg1, Re, and Rg3 on Escherichia coli lipopolysaccharide-induced stress. Our results showed that Rg3 ameliorated growth inhibition and fever, as well as decreased the production of stress-related hormones in broilers with stress. The protective effect of Rg3 on the stressed chicks may be largely mediated by regulating inflammatory response and oxidative damage. Moreover, real-time quantitative-polymerase chain reaction (RT-qPCR) results demonstrated that Rg3 upregulated mRNA expression of mTOR, HO-1, and SOD-1. These results suggested that ginsenoside Rg3 and ginsenoside products contains Rg3 deserve further study for the control of immunological stress and inflammation in broiler chicks.

Hepatic Proteomic Analysis Reveals That Enhanced Carboxylic Acid Metabolism and Oxidoreduction Promote Muscle and Fat Deposition in Muscovy Duck

Simple Summary

Liver plays an important role in lipid synthesis and muscle growth in poultry. The current study measured the growth traits and the proteome of Muscovy duck liver at 14, 28, 42, and 56 days, aiming at exploring the key regulatory proteins for intramuscular fat deposition and muscle growth. The results showed that Muscovy duck grew most rapidly at 28 vs. 42 days of age, subcutaneous and abdominal fat were deposited rapidly, but intramuscular fat content decreased. At the same time, the abundance of liver proteins regarding the tricarboxylic acid cycle and oxidoreduction increased significantly. This study provides a profile of the fat deposition and liver proteome for Muscovy duck.

Abstract

Liver is responsible for 90% of lipid synthesis in poultry; thus, it plays an important role in the growth of Muscovy ducks, which have a high fat deposition ability in a time-dependent manner. Therefore, male Muscovy ducks at 14, 28, 42, and 56 days were selected for body weight (BW), carcass weight (CW), subcutaneous fat thickness (SFT), abdominal fat weight (AFW), intramuscular fat content (IMF), and breast muscle fiber (BMF) diameter and density determination. Two-dimensional electrophoresis (2-DE) combining liquid chromatography linked to tandem mass spectrometry (LC-MS/MS) was used to analyze proteomic changes in liver at each stage. The BW, CW, AFW, SFT, and BMF diameter and density were significantly increased, while IMF content was significantly decreased at 28 to 42 days of age (p < 0.05). There were 57 differentially abundant protein (DEP) spots representing 40 proteins identified among the ages, in which 17, 41 and 4 spots were differentially abundant at 14 vs. 28, 28 vs. 42, and 42 vs. 56, respectively. Gene Ontology enrichment analysis found that DEPs were mostly enriched in the oxidation-reduction process, carboxylic acid metabolism, etc. Protein–protein interaction showed that catalase (CAT), triosephosphate isomerase (TPI), and protein disulfide-isomerase (PDI) were the key proteins responsible for the growth of Muscovy duck. In conclusion, 28 to 42 days of age is the crucial period for Muscovy ducks, and the ability of metabolism and antioxidants were significantly enhanced in liver.

A critical review of advancement in scientific research on food animal welfare-related air pollution

Air pollution generates hazardous pollutants that have resulted in safety, health, and other welfare issues of food animals. This paper reviewed scientific research advancement in food animal welfare-related air pollution based on 219 first-hand research publications in refereed journals (referred to as "RPs") over the past nine decades. Scientific studies in this area began in the 1930s. The number of RPs has increased significantly with each decade from the 1960s to the 1980s, then decreased until the 2010s. Twenty-six countries have contributed to this multidisciplinary research. About 52% of the studies were conducted in the U.S. and U.K. Research activities have surged in China since the 2010s. On-farm discoveries in air toxicity that resulted in animal death or injury were all from observational studies. About 75% of the studies were experimental and conducted primarily under laboratory conditions. Ammonia (NH₃) was the main pollutant in 59% of the RPs, followed by dust, hydrogen sulfide (H₂S), bacteria and endotoxins, carbon dioxide (CO₂), carbon monoxide (CO), silo gas, sulfur dioxide (SO₂), and odor. Approximately 23% of RPs reported multiple pollutants in the same study. The most intensively studied animal species were poultry (broilers, hens, turkeys, ducks, and eggs and embryos in 44% of the RPs) and pigs (also 44%), followed by cattle, and sheep and goats. Scientific investigations in this area were driven by the research focuses in the areas of animal agriculture and industrial air pollution. Some major research teams played important roles in advancing scientific research. However, research in this area is still relatively limited. There is a great need to overcome some technical challenges and reverse the trend of decreasing research activities in North America and Europe.