Determination of gastrointestinal passage rate using three different markers in laying hens

Investigation of Potential Gut Health Biomarkers in Broiler Chicks Challenged by Campylobacter jejuni and Submitted to a Continuous Water Disinfection Program

The exploration of novel biomarkers to assess poultry health is of paramount importance, not only to enhance our understanding of the pathogenicity of zoonotic agents but also to evaluate the efficacy of novel treatments as alternatives to antibiotics. The present study aimed to investigate potential gut health biomarkers in broiler chicks challenged by Campylobacter jejuni and subjected to a continuous water disinfection program. A total of 144 one-day-old hatched broiler chicks were randomly allocated to four treatment groups with four replicates each, according to the following experimental design: Group A received untreated drinking water; Group B received drinking water treated with 0.01-0.05% v/v Cid 2000™ (hydrogen peroxide, acetic acid and paracetic acid); Group C was challenged by C. jejuni and received untreated drinking water; and Group D was challenged by C. jejuni and received drinking water treated with 0.01-0.05% v/v Cid 2000™. The use of Cid 2000™ started on day 1 and was applied in intervals until the end of the experiment at 36 days, while the C. jejuni challenge was applied on day 18. Potential biomarkers were investigated in serum, feces, intestinal tissue, intestinal content, and liver samples of broilers. Statistical analysis revealed significant increases (p < 0.001) in serum cortisol levels in C. jejuni-challenged broilers. Serum fluorescein isothiocyanate dextran (FITC-d) increased significantly (p = 0.004) in broilers challenged by C. jejuni and treated with drinking water disinfectant, while fecal ovotransferrin concentration also increased significantly (p < 0.001) in broilers that received the drinking water disinfectant alone. The gene expression levels of occludin (p = 0.003) and mucin-2 (p < 0.001) were significantly upregulated in broilers challenged by C. jejuni, while mucin-2 significantly increased in birds that were challenged and received the drinking water disinfectant (p < 0.001). TLR-4 expression levels were significantly (p = 0.013) decreased in both groups that received the drinking water disinfectant, compared to the negative control group. Finally, the C. jejuni challenge significantly increased (p = 0.032) the crypt depth and decreased (p = 0.021) the villus height-to-crypt-depth ratio in the ileum of birds, while the tested disinfectant product increased (p = 0.033) the villus height in the jejunum of birds. Furthermore, the counts of C. jejuni in the ceca of birds (p = 0.01), as well as its translocation rate to the liver of broilers (p = 0.001), were significantly reduced by the addition of the water disinfectant. This research contributes to novel insights into the intricate interplay of water disinfection and/or C. jejuni challenge with potential intestinal biomarkers. In addition, it emphasizes the need for continued research to unveil the underlying mechanisms, expands our understanding of broiler responses to these challenges and identifies breakpoints for further investigations.

Non-starch polysaccharide degradation in the gastrointestinal tract of broiler chickens fed commercial-type diets supplemented with either a single dose of xylanase, a double dose of xylanase, or a cocktail of non-starch polysaccharide-degrading enzymes

The aim of this study was to examine non-starch polysaccharide (NSP) degradation in the gastrointestinal tract of chickens fed a range of commercial-type diets supplemented with a commercial dose of xylanase, a double dose of xylanase or a cocktail of NSP - degrading enzymes. Cobb 500 broilers (n = 1,080) were fed 12 dietary treatments; 4 diets with differing primary grain sources (barley, corn, sorghum, and wheat) and three different enzyme treatments (commercial recommended dose of xylanase (16,000 BXU/kg), a double dose of xylanase (32,000 BXU/kg) or an NSP-degrading enzyme cocktail (xylanase, β-glucanase, cellulase, pectinase, mannanase, galactanase, and arabinofuranosidase at recommended commercial levels). There were 108 pens, approximately 10 birds per pen, 9 replicates per dietary treatment. The diets were fed as 3 phases, starter (d 0-12), grower (d 12-23), and finisher (d 23-35). On bird age d 12, 23, and 35, performance (total pen body weight, feed intake, and feed conversion ratio corrected for mortality [cFCR]), litter and excreta dry matter content, and ileal and total tract soluble and insoluble NSP degradability and free oligosaccharide digestibility was determined. On d 35, the quantity of NSP in the gizzard, jejunum, ileum and excreta was determined. Results from this study showed that the double xylanase dose and NSP-ase cocktail had positive impacts on starter phase performance in birds fed the corn- and wheat-based diets. In the grower phase in birds fed the barley-based diet, these enzyme treatments improved cFCR and increased litter dry matter content. The NSP-ase cocktail had a negative impact on finisher phase cFCR in birds fed the sorghum-based diet. The double xylanase dose induced a positive impact on NSP degradability and free oligosaccharide digestibility. In conclusion, there appears to be advantages to feeding broilers a double xylanase dose, but lack of consistency when using an NSP-ase cocktail containing many enzymes.

Short-chain fatty acids promote jejunal barrier function and caecal muscle contractibility in laying hens ex vivo

1. Short-chain fatty acids (SCFA) exert beneficial actions in the gut; nevertheless, information about the effect of SCFA on physiological responses in the small intestine of chickens is rare.2. The aim of this study was to assess the effect of 1) different molar acetate:butyrate ratios (Ac:But; Experiment 1; 78.5% acetate and 7.3% butyrate versus 71.4% acetate and 14.0% butyrate) and 2) SCFA concentrations (Experiment 2; final concentration in chambers: 70.5 versus 141 µmol SCFA/ml buffer) on the jejunal and caecal contractibility and jejunal barrier function in laying hens. The change in muscle contractibility due to the SCFA was measured in mid-jejunal and caecal segments (n = 4 each per hen) from four laying hens using the organ bath system after precontraction with acetylcholine for 15 min. Changes in short-circuit current (I_SC) and transepithelial tissue conductivity (G_T) as indicators for net ion flux and barrier function, respectively, were measured in mid-jejunal tissue (n = 3/hen and treatment), mounted into Ussing chambers.3. In Experiment 1, the addition of SCFA, irrespective of the Ac:But ratio, decreased jejunal muscle tension (P < 0.05), jejunal G_T as well as caused a less negative I_SC (P < 0.05). In Experiment 2, the increasing SCFA concentrations increased the caecal muscle contraction and jejunal I_SC by 75.6% while decreasing the G_T by up to 19.6% (P < 0.05).4. In conclusion, results demonstrate that increasing butyrate proportions and SCFA concentrations stimulate caecal muscle contraction, thereby increasing caecal mixing and emptying in vivo. Jejunal I_SC and G_T support a strong SCFA sensing capacity in the jejunum, as both, more butyrate and higher SCFA, increased mucosal ion uptake and barrier function.

Rate of feed passage in Japanese quail

The rate of passage (ROP) in the gastrointestinal tract (GIT) influences the exposure time of food to the digestion and absorption processes. Consequently, ROP affects the efficiency of nutrient utilization and energy from the diet. This study aimed to determine the physiological parameters that characterize the digestive response, such as first appearance time (FAT), ROP, mean retention time (MRT) and transit time (TT) in adult Japanese quail (Coturnix coturnix japonica), and to evaluate the effects of sex, apparent metabolizable energy corrected for nitrogen balance (AMEn) content in the diet and different types of markers on these parameters. In the first trial, we investigated the effects of sex and AMEn level (high- and low-energy diet) on the FAT parameter. Thirty-two male and 32 female Japanese quail were randomly allocated to 8 battery cages and assigned to 4 treatments in a 2 × 2 factorial design with 4 replicates of 4 birds for each treatment. To determine the FAT, ferric oxide (1%) was added to the diet, and the excreta of the quail was monitored until the first appearance of the marker. The results indicated significant differences (P < 0.05) in the FAT between males (100 min) and females (56 min), regardless of the AMEn content. In the second trial, thirty-two 32-week-old female Japanese quail in the laying phase were assigned to four treatments in a 2 × 2 factorial design, in which the main independent variables were type of marker (Cr or Ti) and AMEn level (high- and low-energy diets). In order to determine ROP (ET1%), MRT and TT (ET100%), the markers (0.5%: Cr2O3 and 0.5%: TiO2) were added to the diets, and the excreta were collected for 750 min. The excretion times for 1% (ET1%), 25% (ET25%), 50% (ET50%), 75% (ET75%) and 100% (ET100%) were estimated using cumulative excretion curves. No effect was detected for the AMEn level (P > 0.05); however, the effect of different marker types was significant (P < 0.05). This difference increased with time and ET100% was estimated to occur at 59 min. The ROP was estimated to be 68 min. The TT was estimated to be 540 min using Cr and 599 min using Ti, with an average MRT value of 0930 h. Taken together, our findings support the hypothesis that Japanese quail digestion through the GIT can be dynamic and differ based on sex or marker type.