Biomarkers of gastrointestinal functionality in animal nutrition and health

Excreta biomarkers in response to different gut barrier dysfunction models and probiotic supplementation in broiler chickens

Increased intestinal permeability (IP) and inflammation are both linked with functionality of the intestinal barrier and in particular enterocytes. Currently, almost all assessment methods of the intestinal barrier function are invasive. The present study aimed to quantify selected proteins as novel biomarkers in excreta of broiler chickens to facilitate non-invasive assessment of gut barrier function using enzyme-linked immunosorbent assays (ELISA). It was further hypothesised that probiotics as feed additives may counteract gut barrier dysfunction. A 3 × 2 factorial arrangement of treatments was used with the main factors being gut barrier dysfunction models (control, rye-based diet, and dexamethasone-DEX) with and without probiotic supplementation (a three-strain Bacillus) using 72 male Ross 308 day-old chickens. Each of the 6 experimental treatments was replicated 12 times. On d 21 of age, fluorescein isothiocyanate dextran (FITC-d) uptake into serum was examined to test IP. Fresh excreta samples were collected on d 20. The biomarkers included alpha-1 antitrypsin (A1AT), intestinal fatty acid binding protein (I-FABP), lipocalin-2 (LCN2), fibronectin (FN), intestinal alkaline phosphatase (IAP), ovotransferrin (OVT) and superoxide dismutase [Cu-Zn] (SOD1). Only DEX increased (P<0.001) FITC-d passage to the blood on d 21 of age, indicating a greater IP. The excreta concentrations of A1AT, I-FABP and SOD1 were unaltered by the experimental treatments. DEX increased (P<0.05) FN concentration in excreta compared with control birds. Conversely, inclusion of rye in the diet reduced (P<0.05) FN but increased (P<0.001) OVT in excreta. Independently, DEX decreased IAP (P<0.05) in excreta compared with control and rye-fed birds. The excreta concentration of LCN2 tended (P = 0.086) to increase in birds injected by DEX. There was no demonstrable effect of probiotic addition on any of the studied parameters. Among the tested biomarkers, FN, IAP, and LCN2 revealed promise as biomarkers of intestinal barrier function quantified by ELISA kits.

Amaranth Meal and Environmental Carnobacterium maltaromaticum Probiotic Bacteria as Novel Stabilizers of the Microbiological Quality of Compound Fish Feeds for Aquaculture

Fish feed should be characterized by microbiological stability to guarantee the optimal health of farmed fish. The aim of this study was to determine the efficacy of amaranth meal (Amaranthus cruentus) and a highly active environmental strain of probiotic bacteria, Carnobacterium maltaromaticum, as novel supplements that stabilize the quantitative and qualitative composition of microbiota in compound fish feeds for aquaculture, regardless of storage temperature. The total viable counts of mesophilic bacteria at 28 °C (TVC 28 °C), hemolytic mesophilic bacteria (Hem 37 °C), Staphylococcus sp. bacteria, aerobic spore-forming bacteria (ASFB), sulfite-reducing anaerobic spore-forming Clostridium sp. bacteria, yeasts, and molds were analyzed in control feed (CF), in feed supplemented with amaranth meal (AF), and in feed supplemented with amaranth meal and C. maltaromaticum (ACF), stored at a temperature of 4 °C and 20 °C for 98 days. Amaranthus cruentus and C. maltaromaticum significantly reduced bacterial counts in fish feeds, regardless of the temperature and duration of storage. The antibacterial and antifungal effects of the tested additives were statistically significant (p ≤ 0.05). The studied novel supplements contribute to the microbiological safety of compound fish feeds. The tested additives could be recognized as the key ingredients of organic, environmentally friendly fish feeds, which guarantee the high quality of fish intended for human consumption.

Technical note: fluorescein as an indicator of enteric mucosal barrier function in preruminant lambs

Increased intestinal permeability can be observed during the physiologic stress response and has been linked to suppression of animal health and performance. Previously published data have shown the efficacy of fluorescein isothiocyanate dextran (FITC-d; 4.17 mg/kg) as a marker of enteric inflammation and mucosal barrier function in multiple species. Fluorescein is a smaller, less expensive alternative molecule possessing similar properties. The following two experiments compared FITC-d and fluorescein as potential indicators of intestinal permeability in pre- and postweaned lambs administered daily intramuscular injections of dexamethasone (Dex; 0.1 mg/kg) for 1 wk. Experiment 1 consisted of five preweaned lambs that were placed in one of two treatment groups: fluorescein with Dex (F+Dex) or fluorescein only (F). On day 7, blood was collected before and 1 h after oral administration of fluorescein (50 mg/kg). Experiment 2 included 12 weaned lambs and four treatment groups: F+Dex, F, FITC-d with Dex (Fd+Dex), and FITC-d only (Fd). On day 7, blood was collected before and 2 h after oral administration of FITC-d (4.17 mg/kg) or fluorescein (50 mg/kg). Plasma fluorescence was reported as the ratio between T1h/T0 or T2h/T0 for experiment 1 or 2, respectively. Experiment 1 showed a significant increase in T1h/T0 ratio of F+Dex relative to F lambs (P = 0.05) indicative of increased leaky gut; however, no differences (P = 0.22) were obtained in experiment 2. Results of these experiments suggest fluorescein may serve as a suitable marker of enteric permeability in preruminant lambs, but not in those with functional rumens.

Effect of broiler genetics, age, and gender on performance and blood chemistry

A total of 640 broilers were used to determine the effects of strain, sex, and age on hematology and blood chemistry using rapid detection devices. Day old chicks from two genetic lines of common fast-growing and high-yield broiler strains were sexed and allocated to 40 pens (16 birds per pen) containing either male or female and Ross or Cobb strains (n = 10). Venous blood was analyzed weekly using 2 broilers from each pen (n = 20) using the i-STAT® Alinity Handheld Clinical Analyzer, Zoetis Vetscan VS2, and iCheck™ Carotene devices at 14, 21, 28, 35, and 42 d, as well as growth performance. Post-mortem health tracking metrics were also recorded on 42 d. Broilers were deemed healthy based on posting data results and performed in accordance with industry standards with males presenting greater BW and reduced FCR than female broilers. Ross broilers displayed greater BW to 14 d with similar FCR compared with Cobb birds. Day of age had a highly significant impact on blood calcium, phosphorus, potassium, sodium, chloride, carotene, aspartate aminotransferase, creatine kinase, bile acids, uric acid, total protein, albumin, globulin, total carbon dioxide, hematocrit, and malondialdehyde. Male broilers had reduced blood sodium, chloride, carotene, uric acid, albumin, and increased total protein, glucose, and total carbon dioxide. Ross broilers had greater blood potassium, and sodium, as well as reduced uric acid, total protein, globulin, and malondialdehyde, compared with Cobb birds. These results demonstrated the effectiveness of point-of-care devices in measuring blood chemistry and hematology in modern broilers. These data can be utilized to determine normal healthy blood ranges in these types of broilers when accounting for strain, sex, and age.

The role of oligosaccharides and polysaccharides of xylan and mannan in gut health of monogastric animals

Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells of the body. As such, the physical, chemical and nutrient composition of the diet influences overall GI function, effectively as an immune organ. With the improvement in feed technology, agro-industrial co-products that are high in fibre have been widely used as a feed ingredient in the diets of pigs and poultry. Arabinoxylan (AX) and mannan are the most abundant hemicellulosic polysaccharides present in cereal grain and co-product ingredients used in the livestock industry. When monogastric animals consume diets containing high amounts of AX and mannans, stimulation of GI immune cells may occur. This involves the activation of several cellular and molecular pathways of the immune system and requires a considerable amount of energy and nutrients to be expended by the animal, which may ultimately influence overall health and growth performance of animals. Therefore, a better understanding of the role of AX and mannan in immune modulation will be helpful in modulating untoward GI immune responses, thereby minimising nutrient and energy expenditure toward this effort. This review will summarise pertinent research on the role of oligosaccharides and polysaccharides containing AX and mannans in immune modulation in order to preserve gut integrity.

Evaluation of a Bacillus -Based Direct-Fed Microbial on Aflatoxin B1 Toxic Effects, Performance, Immunologic Status, and Serum Biochemical Parameters in Broiler Chickens

The aim of the present study was to evaluate the effect of a commercial Bacillus direct-fed microbial (DFM) on aflatoxin B1 toxic effects, performance, and biochemical and immunologic parameters in broiler chickens. Ninety 1-day-old Cobb 500 male broiler chicks were raised in floor pens for a period of 21 days. Chicks were neck-tagged, individually weighed, and randomly allocated to one of three groups: Negative control (basal feed), aflatoxin B1 (basal feed + 2 ppm AFB1), and DFM (basal feed + 2 ppm AFB1 + Bacillus direct-fed microbial). Each group had three replicates of 10 chickens (n = 30/group). Body weight and body weight gain were calculated weekly, while feed intake and feed conversion ratio were determined when broilers were 21 days old. On day 21, all chickens were bled, gastrointestinal samples were collected, and spleen and bursa of Fabricius were weighed. This study confirmed that 2 ppm of AFB1 causes severe detrimental effects on performance, biochemical parameters, and immunologic parameters, generating hepatic lesions in broiler chickens (P < 0.05). However, it was also observed that DFM supplementation provided beneficial effects that might help to improve gut barrier function, anti-inflammatory and antioxidant activities, as well as humoral and cellular immunomodulation. The results of the present study suggest that this Bacillus-DFM added at a concentration of 10⁶ spores/gram of feed can be used to counteract the negative effects that occur when birds consume diets contaminated with AFB1, showing beneficial effects on performance parameters, relative organ weights, hepatic lesions, immune response, and serum biochemical variables. The addition of this Bacillus-DFM might mitigate and decrease aflatoxicosis problems in the poultry industry, improving food security, alleviating public health problems, and providing economic benefits. Future studies are needed to fully elucidate the specific mechanisms by which this Bacillus-DFM counteracts the toxic effects of aflatoxin B1.

Subluminal Focal Lesions in Peyer's Patches in the Terminal Ileum of Pigs Fed With Different Physical Forms of One Same Diet

Retrograde backflow of cecum chyme and consequent ascendent colonization of the foregut may occur via the ileocecal valve (IV) under predisposing circumstances. The Peyer's patches (PPs) in the terminal ileum (TI) play a crucial role in targeting antigens and act as a first line of blockage of pathogens in the small intestine. In view of the established impact of the physical form of the diet (grinding and compaction of ingredients) on the physicochemical and microbiological composition of digesta throughout the different gastrointestinal tracts, special attention was paid to PP reaction following different dietary treatments. The aim of this study was to explore the effect of different physical forms of one diet (identical for botanical and chemical composition) administered to growing pigs on macro- and microscopic morphology of PPs in the last 3 cm of the TI, as a region of interest immediately close to the IV involved in the prevention of retrograde contamination of the small intestine. The diet effect was tested after 4 weeks of experimental feeding on PPs of 32 growing pigs, fed with four dietary treatments differing for the physical form: FP—finely ground pelleted diet (dMEAN, 0.463 mm); CM—coarsely ground meal diet (dMEAN, 0.880 mm); CP—coarsely ground pelleted diet (dMEAN, 0.836); and CE—coarsely ground extruded diet (dMEAN, 0.659). A higher prevalence of subluminal focal liquefactive necrosis (FLN) in the last 3 cm of the TI was observed in pigs fed with the CE and the FP diet (n. 3/8 or 37.5% and n. = 1/8 or 12.5%, respectively) (p = 0.076). FLN negatively and significantly correlated with the pH value of digesta of the last part of the small intestine (ρ = −0.361; p = 0.026). All animals enrolled appeared clinically healthy throughout the trial. Growth performance were not affected by the different dietary treatments, but fecal dry matter and pH values were affected in a significant way. Results about the morphology of PPs assessed in this trial can be suggestive of the physical form of the diet as a contributing factor to the onset of different antigenic potentials of the intestinal chyme.

Bacillus subtilis and Bacillus licheniformis reduce faecal protein catabolites concentration and odour in dogs

BACKGROUND

Direct-fed microbials (DFM), such as Bacillus subtilis and Bacillus licheniformis, may improve gut functionality of the host by favouring non-pathogenic bacteria and reducing the formation of putrefactive compounds. The aim of this study was to assess the nutrient digestibility, faecal characteristics and intestinal-fermentation products in dogs fed diets with Bacillus subtilis and Bacillus licheniformis. Sixteen dogs were randomly divided into two groups. Every eight dogs were fed with the control diet or the diet with the addition of 62.5 g of DFM (B. subtilis and B. licheniformis)/ton. Diets were provided throughout a 20-day adaptation period, followed by 5 days of total faecal collection. Nutrient digestibility and the metabolisable energy of the diets, plus the dogs' faecal characteristics and intestinal fermentation products were assessed.

RESULTS

There were no differences in nutrient digestibility (P > 0.05). However, DFM supplementation improved faecal score and resulted in less fetid faeces (P < 0.001). DFM inclusion reduced (P < 0.05) the biogenic amines concentration: putrescine, spermidine and cadaverine, besides the concentration of phenols and quinoline.

CONCLUSIONS

The use of B. subtillis and B. licheniformis as DFM reduce the concentration of nitrogen fermentation products in faeces and faecal odour, but the digestibility of nutrients is not altered in dogs.

Effect of dietary 25-hydroxycholecalciferol supplementation and high stocking density on performance, egg quality, and tibia quality in laying hens

This study was conducted to determine the effects of 25-hydroxycholecalciferol (25-OH-D₃) on performance, egg quality, tibia quality, and serum hormones concentration in laying hens reared under high stocking density. A total of 800 45-week-old Lohmann laying hens were randomly allotted into a 2 × 2 factorial design with 2 levels of dietary 25-OH-D₃ levels (0 and 69 μg/kg) and 2 rates of stocking densities [506 (low density) and 338 (high density) cm²/hen]. Laying hens were monitored for 16 wk. High stocking density decreased laying rate, egg weight, and feed intake compared with low stocking density (P < 0.01) during 1 to 8 wk and 1 to 16 wk. Overall, high stocking density increased eggshell lightness value and decreased shell redness and yellowness value, strength, thickness, and relative weight compared with low stocking density (P < 0.05). Dietary supplementation with 25-OH-D₃ reduced the value of the eggshell lightness and increased its yellowness and eggshells weight (P ≤ 0.05). The increase in eggshell thickness was more pronounced when 25-OH-D₃ was supplemented to layers under high stocking density (interaction, P < 0.05). Layers under high stocking density had lower ash content and calcium content in the tibia than layers under low stocking density (P = 0.04); dietary 25-OH-D₃ increased tibia strength compared with no addition (P = 0.05). Layers under high stocking density had higher serum concentrations of 25-OH-D₃, corticosterone (CORT), lipopolysaccharide (LPS), and osteocalcin (OC; P < 0.05), lower content of parathyroid hormone (PTH) compared with layers under low stocking density (P < 0.01). Dietary 25-OH-D₃ increased serum concentration of 25-OH-D₃, carbonic anhydrase (CA), and calcitonin (CT) (P < 0.01) and reduced corticosterone, lipopolysaccharide and osteocalcin concentration (P ≤ 0.05). The increase effect in PTH was more pronounced when 25-OH-D₃ was supplemented to layers under high stocking density (interaction, P = 0.05). Overall, the results gathered in this study indicate that high stocking density result in reducing production performance, shell color and quality, and tibia health, whereas dietary 25-OH-D₃ was able to maintain tibia health and to mitigate the negative impact of high stocking density on productive performance.

Isolation of swine-derived Lactobacillus plantarum and its synergistic antimicrobial and health-promoting properties with ZnO nanoparticles

AIMS

The purpose of this study was to isolate Lactobacillus from gastrointestinal tract of healthy postweaning piglets and investigate its synergistic antimicrobial and probiotic effects with ZnO nanoparticles (nZnO).

METHODS AND RESULTS

Of the 128 isolates, Lactobacillus plantarum BLPL03 was selected based on its excellent acid and bile salt tolerance properties. Lactobacillus plantarum BLPL03 was sensitive to β-lactams, macrolides, amphenicols and cephalosporins, whereas it displayed the steady resistance to aminoglycosides, tetracyclines, quinolones and peptide antibiotics. In vitro analysis of antibacterial activities showed that L. plantarum BLPL03 inhibited the four common food-borne pathogenic bacteria including Escherichia coli O157:H7 CMCC 44828, Salmonella Typhimurium ATCC 13311, Staphylococcus aureus CMCC 26003 and Listeria monocytogenes CMCC 54007 in synergy with nZnO. Furthermore, the quantitative polymerase chain reaction test demonstrated that the combined administration of L. plantarum BLPL03 fermentation liquor (LFL) and nZnO synergistically elevated the faecal number of Bifidobacterium by 73·19-fold, and reduced the two potential enteropathogenic bacteria Enterobacteriaceae and Clostridium perfringens in mice challenged with Salm. Typhimurium. Finally, dietary supplementation with low dose of nZnO (20 mg kg^-1 ) when combined with LFL administration enhanced final body weight, fur appearance and average daily gain, and decreased feed conversion ratio and diarrhoea incidence in weaned piglets. The faecal Bifidobacterium and Lactobacillus of piglets were dramatically enhanced by 81·96- and 3·15-fold, respectively, after administration of a mixture of nZnO and LFL. Meanwhile, combination of nZnO with LFL resulted in low levels of Bacteroides, Enterococcus, and Enterobacteriaceae.

CONCLUSIONS

A combination of nZnO and LFL exhibits potential health-benefit properties for the control of gut microbial composition by their synergistic antimicrobial and probiotic effects.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study may provide a potential nutritional strategy to improve performance and gut health of animals with gut microbiota disorders caused by pathogen infections and weanling, and so on.

The Control of Intestinal Inflammation: A Major Objective in the Research of Probiotic Strains as Alternatives to Antibiotic Growth Promoters in Poultry

The reduction of antimicrobial resistance is a major challenge for the scientific community. In a few decades, infections by resistant bacteria are forecasted to be the main cause of death in the world. The withdrawal of antibiotics as growth promoters and their preventive use in animal production is essential to avoid these resistances, but this may impair productivity and health due to the increase in gut inflammation. This reduction in productivity aggravates the problem of increasing meat demand in developing countries and limits the availability of raw materials. Probiotics are promising products to address this challenge due to their beneficial effects on microbiota composition, mucosal barrier integrity, and immune system to control inflammation. Although many modes of action have been demonstrated, the scientific community is not able to describe the specific effects that a probiotic should induce on the host to maximize both productivity and animal health. First, it may be necessary to define what are the innate immune pathways acting in the gut that optimize productivity and health and to then investigate which probiotic strain is able to induce the specific effect needed. This review describes several gaps in the knowledge of host-microbiota-pathogen interaction and the related mechanisms involved in the inflammatory response not demonstrated yet in poultry.

Early-Life Intervention Using Fecal Microbiota Combined with Probiotics Promotes Gut Microbiota Maturation, Regulates Immune System Development, and Alleviates Weaning Stress in Piglets

Previous studies have suggested that immune system development and weaning stress are closely related to the maturation of gut microbiota. The early-life period is a “window of opportunity” for microbial colonization, which potentially has a critical impact on the development of the immune system. Fecal microbiota transplantation (FMT) and probiotics are often used to regulate gut microbial colonization. This study aims to test whether early intervention with FMT using fecal microbiota from gestation sows combined with Clostridium butyricum and Saccharomyces boulardii (FMT-CS) administration could promote the maturation of gut microbiota and development of immune system in piglets. Piglets were assigned to control (n = 84) and FMT-CS treatment (n = 106), which were treated with placebo and bacterial suspension during the first three days after birth, respectively. By 16S rRNA gene sequencing, we found that FMT-CS increased the α-diversity and reduced the unweighted UniFrac distances of the OTU community. Besides, FMT-CS increased the relative abundance of beneficial bacteria, while decreasing that of opportunistic pathogens. FMT-CS also enhanced the relative abundance of genes related to cofactors and vitamin, energy, and amino acid metabolisms during the early-life period. ELISA analysis revealed that FMT-CS gave rise to the plasma concentrations of IL-23, IL-17, and IL-22, as well as the plasma levels of anti-M.hyo and anti-PCV2 antibodies. Furthermore, the FMT-CS-treated piglets showed decreases in inflammation levels and oxidative stress injury, and improvement of intestinal barrier function after weaning as well. Taken together, our results suggest that early-life intervention with FMT-CS could promote the development of innate and adaptive immune system and vaccine efficacy, and subsequently alleviate weaning stress through promoting the maturation of gut microbiota in piglets.

Impact of early weaning on small intestine, metabolic, immune and endocrine system development, growth and body composition in artificially reared lambs

AbstractThis study evaluated the effect of early weaning (EW) of artificially reared lambs using a restricted milk replacer (MR) feeding and step-down weaning system on the short- and long-term effects on growth, feed intake, selected blood metabolites and hormones, body composition, and small intestine development. Mixed-sex twin-born 2 to 5 d old lambs were randomly allocated to individual pens and fed MR at 20% of initial individual BW in week 1 and 15% in week 2 followed by weaning off MR by the end of week 4 (EW; n = 16) or week 6 (Control; Ctrl, n = 16) using a step-down procedure. Concentrate starter and fiber diets were offered ad libitum to week 9, then gradually removed over a 10-d period. All lambs were managed as a single group on pasture from weeks 6 to 16 of the trial. Feed intake was recorded daily in the first 6 wk, and BWs recorded weekly. At weeks 2, 4, 6, and 8, and pre- and postclostridial vaccination at week 8, blood samples were collected for analysis of selected blood metabolites, IGF-1, and immune function. Body composition was evaluated in eight animals per group at weeks 4 and 16 after euthanasia, and duodenal samples collected for histomorphometric evaluation. Early weaned lambs had lower DM, ME, CP, and NDF intake than Ctrl lambs at 21, 15, 21, and 36 d of rearing, respectively (P < 0.001), driven by lower intakes of MR from day 15 (P < 0.001) as per the experimental design, and lower total DMI of fiber (P = 0.001) from 21 to 42 d of rearing. Lamb BW tended (P = 0.097) to be lower in EW than Ctrl lambs from 5 to 10 wk of rearing, with lower ADG in EW lambs from weeks 3 to 6 (P = 0.041). Early weaning had negligible effects on duodenal morphology, organ, and carcass weights at weeks 4 and 16. Plasma metabolites (urea nitrogen, triglycerides, NEFA, glucose, and total protein) were similar between groups, while β-hydroxybutyrate was greater in EW than Ctrl lambs at weeks 4 and 6 (P = 0.018) but not week 8 indicative of early rumen development. Serum IGF-1 tended to be lower in EW than Ctrl lambs from weeks 2 to 6 only (P = 0.065). All lambs developed antibody responses postvaccination and there was no effect of treatment (P = 0.528). The results of this study illustrate that artificially reared lambs can be weaned off MR by 4 or 6 wk of rearing without compromising growth, small intestine morphology, major organ development, and body composition, nor immune function at either 4 (preweaning) or 16 (postweaning) wk of age.

Alteration of the Antioxidant Capacity and Gut Microbiota under High Levels of Molybdenum and Green Tea Polyphenols in Laying Hens

High dietary levels of molybdenum (MO) can negatively affect productive performances and health status of laying hens, while tea polyphenol (TP) can mitigate the negative impact of high MO exposure. However, our understanding of the changes induced by TP on MO challenged layers performances and oxidative status, and on the microbiota, remains limited. The aim of the present study was to better understand host (performances and redox balance) and microbiota responses in MO-challenged layers with dietary TP. In this study, 200 Lohmann laying hens (65-week-old) were randomly allocated in a 2 × 2 factorial design to receive a diet with or without MO (0 or 100 mg/kg), and supplemented with either 0 or 600 mg/kg TP. The results indicate that 100 mg/kg MO decreased egg production (p = 0.03), while dietary TP increased egg production in MO challenged layers (p < 0.01). Egg yolk color was decreased by high MO (p < 0.01), while dietary TP had no effect on yolk color (p > 0.05). Serum alanine transaminase (ALT), aspartate aminotransferase (AST), and malonaldehyde (MDA) concentration were increased by high MO, while total antioxidant capacity (T-AOC), xanthine oxidase (XOD) activity, glutathione s-transferase (GSH-ST), and glutathione concentration in serum were decreased (p < 0.05). Dietary TP was able to reverse the increasing effect of MO on ALT and AST (p < 0.05). High MO resulted in higher MO levels in serum, liver, kidney, and egg, but it decreased Cu and Se content in serum, liver, and egg (p < 0.05). The Fe concentration in liver, kidney, and eggs was significantly lower in MO supplementation groups (p < 0.05). High MO levels in the diet led to lower Firmicutes and higher Proteobacteria abundance, whereas dietary TP alone and/or in high MO treatment increased the Firmicutes abundance and the Firmicutes/Bacteroidetes ratio at phylum level. High MO increased the abundance of Proteobacteria (phylum), Deltaproteobacteria (class), Mytococcales (order), and Nanocystaceae (family), whereas dietary TP promoted the enrichment of Lactobacillus agilis (species). Dietary TP also enhanced the enrichment of Bacilli (class), Lactobacillates (order), Lactobacillus (family), and Lactobacillus gasseri (species). Microbiota analysis revealed differentially enriched microbial compositions in the cecum caused by MO and TP, which might be responsible for the protective effect of dietary TP during a MO challenge.

Biomarkers in Stress Related Diseases/Disorders: Diagnostic, Prognostic, and Therapeutic Values

Various internal and external factors negatively affect the homeostatic equilibrium of organisms at the molecular to the whole-body level, inducing the so-called state of stress. Stress affects an organism's welfare status and induces energy-consuming mechanisms to combat the subsequent ill effects; thus, the individual may be immunocompromised, making them vulnerable to pathogens. The information presented here has been extensively reviewed, compiled, and analyzed from authenticated published resources available on Medline, PubMed, PubMed Central, Science Direct, and other scientific databases. Stress levels can be monitored by the quantitative and qualitative measurement of biomarkers. Potential markers of stress include thermal stress markers, such as heat shock proteins (HSPs), innate immune markers, such as Acute Phase Proteins (APPs), oxidative stress markers, and chemical secretions in the saliva and urine. In addition, stress biomarkers also play critical roles in the prognosis of stress-related diseases and disorders, and therapy guidance. Moreover, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be employed to evaluate these conditions precisely, but with stringent validation and specificity. Considerable scientific advances have been made in the detection, quantitation, and application of these biomarkers. The present review describes the current progress of identifying biomarkers, their prognostic, and therapeutic values.

Biomarkers in Stress Related Diseases/Disorders: Diagnostic, Prognostic, and Therapeutic Values

Various internal and external factors negatively affect the homeostatic equilibrium of organisms at the molecular to the whole-body level, inducing the so-called state of stress. Stress affects an organism's welfare status and induces energy-consuming mechanisms to combat the subsequent ill effects; thus, the individual may be immunocompromised, making them vulnerable to pathogens. The information presented here has been extensively reviewed, compiled, and analyzed from authenticated published resources available on Medline, PubMed, PubMed Central, Science Direct, and other scientific databases. Stress levels can be monitored by the quantitative and qualitative measurement of biomarkers. Potential markers of stress include thermal stress markers, such as heat shock proteins (HSPs), innate immune markers, such as Acute Phase Proteins (APPs), oxidative stress markers, and chemical secretions in the saliva and urine. In addition, stress biomarkers also play critical roles in the prognosis of stress-related diseases and disorders, and therapy guidance. Moreover, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be employed to evaluate these conditions precisely, but with stringent validation and specificity. Considerable scientific advances have been made in the detection, quantitation, and application of these biomarkers. The present review describes the current progress of identifying biomarkers, their prognostic, and therapeutic values.

Genome-wide association scan for QTL and their positional candidate genes associated with internal organ traits in chickens

BACKGROUND

Poultry breeding programs have been focused on improvement of growth and carcass traits, however, this has resulted in correlated changes in internal organ weights and increased incidence of metabolic disorders. These disorders can affect feed efficiency or even cause death. We used a high density SNP array (600 K, Affymetrix) to estimate genomic heritability, perform genome-wide association analysis, and identify genomic regions and positional candidate genes (PCGs) associated with internal organ traits in an F2 chicken population. We integrated knowledge of haplotype blocks, selection signature regions and sequencing data to refine the list of PCGs.

RESULTS

Estimated genomic heritability for internal organ traits in chickens ranged from low (LUNGWT, 0.06) to high (GIZZWT, 0.45). A total of 20 unique 1 Mb windows identified on GGA1, 2, 4, 7, 12, 15, 18, 19, 21, 27 and 28 were significantly associated with intestine length, and weights or percentages of liver, gizzard or lungs. Within these windows, 14 PCGs were identified based on their biological functions: TNFSF11, GTF2F2, SPERT, KCTD4, HTR2A, RB1, PCDH7, LCORL, LDB2, NR4A2, GPD2, PTPN11, ITGB4 and SLC6A4. From those genes, two were located within haplotype blocks and three overlapped with selection signature regions. A total of 13,748 annotated sequence SNPs were in the 14 PCGs, including 156 SNPs in coding regions (124 synonymous, 26 non-synonymous, and 6 splice variants). Seven deleterious SNPs were identified in TNFSF11, NR4A2 or ITGB4 genes.

CONCLUSIONS

The results from this study provide novel insights to understand the genetic architecture of internal organ traits in chickens. The QTL detection performed using a high density SNP array covered the whole genome allowing the discovery of novel QTL associated with organ traits. We identified PCGs within the QTL involved in biological processes that may regulate internal organ growth and development. Potential functional genetic variations were identified generating crucial information that, after validation, might be used in poultry breeding programs to reduce the occurrence of metabolic disorders.

Time-Dependent Changes in the Intestinal Microbiome of Gilts Exposed to Low Zearalenone Doses

Zearalenone is a frequent contaminant of cereals and their by-products in regions with a temperate climate. This toxic molecule is produced naturally by Fusarium fungi in crops. The aim of this study was to determine the influence of low zearalenone doses (LOAEL, NOAEL and MABEL) on the intestinal microbiome of gilts on different days of exposure (days 7, 21 and 42). Intestinal contents were sampled from the duodenal cap, the third part of the duodenum, jejunum, caecum and the descending colon. The experiment was performed on 60 clinically healthy gilts with average BW of 14.5 ± 2 kg, divided into three experimental groups and a control group. Group ZEN5 animals were orally administered ZEN at 5 μg /kg BW, group ZEN10-10 μg ZEN/kg BW and group ZEN15-15 µg ZEN/kg BW. Five gilts from every group were euthanized on analytical dates 1, 2 and 3. Differences in the log values of microbial counts, mainly Escherichia coli and Enterococcus faecalis, were observed between the proximal and distal segments of the intestinal tract on different analytical dates as well as in the entire intestinal tract. Zearalenone affected the colony counts of intestinal microbiota rather than microbiome diversity, and its effect was greatest in groups ZEN10 and ZEN15. Microbial colony counts were similar in groups ZEN5 and C. In the analysed mycobiome, ZEN exerted a stimulatory effect on the log values of yeast and mould counts in all intestinal segments, in particular in the colon, and the greatest increase was noted on the first analytical date.

Role of Feed Processing on Gut Health and Function in Pigs and Poultry: Conundrum of Optimal Particle Size and Hydrothermal Regimens

The aim is to give an overview of available literature data on the role of feed processing on gut health and function with specific focus on particle size and hydrothermal processing. In addition, influence of feed processing on efficacy of exogenous feed enzymes will be discussed. The current feed processing technologies are such that ingredient choices and diet form are refined to improve feed intake and nutrient utilization efficiency. Finer feed particle size enables optimal nutrient utilization and enhances animal performance due to increased surface area allowing better contact with digestive enzymes. Moreover, adequate diminution of feed ingredients is beneficial to feed manufacturing processes such as mixing and hydrothermal treatments including pelleting, extrusion, and expansion. However, emerging trends in consumer and regulatory demands for restriction or cessation of animal production practices such as use of antimicrobial growth promoters are challenging current approaches to feed processing. There is limit as to the fineness of the particle size, as very fine particles negatively affect gut health due to higher incidences of stomach ulceration in pigs and gizzard dysfunction in poultry. Coarse particle size increases stomach and hindgut acidification which may be beneficial in controlling proliferation of enteric pathogens such as salmonella and E. coli. Optimal particle size could be designed in the grinding process using roller or hammer mill. However, since most commercial pigs and poultry diets are subjected to hydrothermal processes, additional reduction of feed particle size is inevitable. The need to achieve high physical quality and to reduce potential levels of feed-borne pathogens such as Salmonella has led to the application of relatively high conditioning temperatures during conventional hydrothermal processes, a practice that does not favor high nutrient utilization and stability of heat sensitive feed additives such as feed enzymes. Therefore, with evolving pig and poultry production practices, the regimens for feed processing will no longer be appreciated only in terms of optimizing nutrients utilization, but also in terms of impact on feed hygienic status, efficacy of feed additives, animal health, and food safety.

Associations between gastrointestinal-tract function and the stress response after weaning in pigs

Psychosocial stress is a major factor driving gastrointestinal-tract (GIT) pathophysiology and disease susceptibility in both humans and animals. Young weaned pigs typically undergo psychosocial and environmental stressors associated with production practices, including separation from their dam, mixing and crowding stress, transport and changed temperature and air-quality parameters, all of which can have significant deleterious impacts not only on performance but also on GIT structure and function, and, therefore, pig health and welfare. Strategies addressing some of these issues are explored in the current review, as well as discussion pertaining to sexual dimorphism in young pigs linked to stressful experiences, with young female pigs seemingly adversely affected more than their male counterparts. However, mechanisms governing susceptibility to stress-induced GIT functionality and disease remain inadequately understood.