Search Results (81)

Early microbial exposure during embryogenesis may shape post-hatch gut development in poultry, yet the effects of sublethal pathogenic exposure and in ovo synbiotics remain unclear. This model-establishment study preliminarily established in ovo Salmonella Enteritidis (SE) infection and synbiotic (SYN) delivery models and evaluated their effects on hatchability, cecal microbiota, intestinal morphology, epithelial turnover, and barrier function in newly hatched chicks. In one group, the air cells of specific pathogen-free White Leghorn eggs were injected with SE on embryonic day 12; in another group, a synbiotic consisting of Lactobacillus plantarum, Pediococcus acidilactici, and inulin was injected into the amniotic cavity on embryonic day 17.5. Sterile saline was injected as the vehicle-only procedural control at the corresponding time points and injection sites. Based on their impacts on hatchability, SE1-L and SYN-H were selected. SE1-L reduced cecal microbial diversity, expanded Proteobacteria and Escherichia–Shigella, increased ileal apoptosis and crypt depth, decreased the villus height-to-crypt depth ratio, downregulated jejunal tight-junction genes, upregulated ileal MYD88 and TNF-α, and increased plasma lipopolysaccharide and D-lactate. In contrast, SYN-H maintained hatchability, promoted early Pediococcus colonization, suppressed potential pathogens, increased ileal villus height and villus height-to-crypt depth ratio, enhanced proliferation, reduced apoptosis, and improved mucosal barrier-related indices. These findings provide preliminary evidence that embryonic SE infection and synbiotic delivery differentially influence early intestinal microbiota succession and gut development in newly hatched chicks. Full article

Using plant byproducts as bioactive sources for in ovo injection (IOI) can enhance embryo development. This study evaluated the effects of air cell IOI of sweet orange peel (SP), pomegranate peel (PP), and olive leaf (OL) aqueous extracts on embryonic days 10 and 18, assessing chicken hatching and post-hatch performance up to 42 days of age. Nine hundred eggs were assigned to 10 treatments. Each treatment had three replicates (n = 30 eggs/replicate) with a 5 × 2 factorial design (uninjected negative control, injection with distilled water as positive control, or injection with 1% SP, PP, or OL on day 10 or 18 of embryogenesis). Compared to the negative control, the results revealed that in ovo-injected substances (IOSs) did not alter hatchability but significantly decreased pipped-chick percentage, the heterophil-to-lymphocyte ratio, malondialdehyde, cholesterol, triglycerides, and glucose levels. However, IOSs were found to increase superoxide dismutase (SOD) levels, liveability, and final body weight. Specifically, SP maximised hatch weight, gut length, and thymus weight, whilst decreasing eggshell conductance and uric acid. SP and OL reduced liver enzyme activities, whereas PP lowered creatinine. Compared to day 10, IOI on day 18 improved hatchability, packed cell volume, SOD activity, liveability, and organ development. In conclusion, IOI with SP or OL, particularly on day 18 of incubation, is recommended to improve antioxidant status, biochemical indices, and cumulative body weight. Full article

This study examined the effects of in ovo silver nanoparticle (AgNP) administration on broiler chicken hatchability, growth performance, physiological and metabolic status, antioxidant capacity, and immune responses. A total of 300 fertilized Cobb500 eggs were assigned to five treatments (5 replicates/treatment, 12 eggs/replicate): non-injected control; vehicle control (0.2 mL sterile 0.9% NaCl/egg); and AgNPs at 10, 15, or 20 ppm injected into their amniotic sac on day (d) 18 of incubation. After hatching, 48 chicks/treatment were assigned to 6 replicate cages (8 birds/replicate) for 35 d. In ovo AgNP administration improved hatchability and reduced embryonic mortality (p < 0.05). Post-hatch, birds originating from AgNP-injected eggs had an improved body weight, body weight gain, and feed conversion ratio, with lower feed intake (p < 0.05). AgNP administration elevated hemoglobin, packed cell volume, growth hormone, serum proteins, alanine aminotransferase activity, and creatinine levels (p < 0.05). AgNPs also improved the lipid profile and increased total antioxidant capacity, catalase and superoxide dismutase activities, lysozyme activity, complement 3, and cytokine concentrations and reduced malondialdehyde levels (p < 0.05). Effects were dose-dependent, with 15 ppm generally leading to better outcomes. These findings suggest that 15 ppm AgNP in ovo administration enhances embryonic viability, physiological resilience, and post-hatch performance in broiler chickens. Full article

Background: Paramagnetic manganese (Mn(II)) has emerged as a promising alternative to gadolinium-based contrast agents (GBCAs) due to its favorable magnetic properties. Despite extensive research, no Mn-based agent has yet achieved clinical translation. Because free Mn(II) is toxic, macromolecular complexes incorporating stable macrocyclic DOTA chelators conjugated to polysaccharides may enhance coordination stability and improve the safety profile of Mn(II)-based contrast agents. Methods: Two chemical routes, maleimide- and ester-mediated, were evaluated for covalent coupling of DOTA-based macrocyclic ligands to the backbone of selected poly- and oligosaccharides. Subsequently, DOTA-modified carboxymethyldextran, aminodextran, and chitosan oligosaccharide were labeled with paramagnetic Mn(II) under mild conditions. ATR-FTIR confirmed the successful conjugation of DOTA chelators to the sugar backbone. The conjugates were further characterized by DLS, ICP-MS, and FPLC. In vitro relaxivity was measured at high field strength to evaluate MRI performance. In vivo contrast efficacy was first assessed using in ovo MRI in chicken embryos and subsequently evaluated by biodistribution studies in nude mice. Results: In vitro relaxivity studies demonstrated higher signal enhancement of the poly-/oligosaccharide-DOTA-Mn(II) conjugates compared with MnCl₂ and the clinical agent gadoteridol (ProHance^®). In ovo MRI showed persistent vascular enhancement up to 120 min, while in nude mice, contrast enhancement was observed in the liver, kidneys, and gallbladder 40 min post-injection. Conclusions: Mn(II)-tagged sugar-based imaging probes may offer a promising non-gadolinium alternative to GBCAs, with tunable biodistribution profiles depending on carrier molecular weight. Full article

There is an energy deficiency during the later stage of embryonic development, as the metabolic demands show an “explosive increase”. Vegetable oils are already used for in ovo feeding in poultry to provide energy for the embryos. What would be the effectiveness of animal oils used as alternative energy sources for the chicken embryo? To find out more, BSF larvae oil was used for in ovo feeding of the chicken embryo in this study. A total of 2300 Arbor Acres chicken eggs were used for incubation. On the tenth day of incubation, 2268 eggs were selected after candling and then divided into three groups for in ovo feeding in the yolk sac on the 11th, 14th, and 17th days of incubation. Each group was divided into seven lots, such as CON−, CON+, L0.1, L0.2, L0.3, L0.4, and L0.5. The CON− and CON+ were not injected. L0.1, L0.2, L0.3, L0.4, and L0.5 were pierced and then received the injection of 0.1 mL, 0.2 mL, 0.3 mL, 0.4 mL, and 0.5 mL of BSF maggot oil per egg, respectively. After hatching, 48 chicks from each lot of each group were housed in cages and then fed the same diet for six weeks. A better hatch rate and growth performance were observed for lots L0.1 and L0.2 compared to the other lots on the 14th and 17th days of incubation (p < 0.05). The injected lots showed reduced levels of low-density lipoprotein (LDL) cholesterol (p < 0.05). The injection of 0.1 mL BSF maggot oil on the 17th day of incubation had 0% embryonic mortality and 100% hatching success. In conclusion, BSF larvae oil can be used as an energy source for in ovo injection, with a dose of 0.1 mL on the 17th day of incubation being most effective and recommended. Full article

The yolk sac (YS) plays a pivotal role in avian embryonic development, contributing to both haematopoiesis and immune maturation. This study aimed to evaluate the effects of in ovo administration of a commercial probiotic blend (Slab51^®) on YS cellular dynamics in chicken embryos. At embryonic day (ED) 18, Ross308 broiler eggs were injected with either the probiotic suspension (P) or sterile saline solution (C). YS tissues were sampled at 8, 12, 24 and 36 h post-inoculation for histological and immunohistochemical analysis. Probiotic-treated embryos exhibited a significant reduction in granulocytic foci within the YS, potentially reflecting enhanced peripheral migration of mature granulocytes. Concurrently, a progressive increase in Iba-1+ macrophages was observed in the probiotic group, suggesting accelerated macrophage differentiation. Immunophenotyping revealed a predominance of M1-iNOS+ macrophages across all timepoints, although a significant increase in M2-CD204+ macrophages was detected at 36 h in probiotic-treated embryos, indicating a possible anti-inflammatory shift. Furthermore, a marked increase in CD31+ endothelial cells in the probiotic group supports an associated rise in neo-angiogenesis. These findings suggest that in ovo probiotic administration modulates the YS microenvironment by promoting early macrophage recruitment, macrophage polarization and vascular remodeling. To our knowledge, this is the first report to demonstrate probiotic-induced structural and immunological alterations in the chicken embryo YS. These results provide novel insights into the early immunomodulatory effects of probiotics and highlight the potential of the YS as a key mediator of host–probiotic interaction during embryogenesis. Full article

Probiotics have been used to promote pioneer colonization by beneficial bacteria in poultry. The purpose of the present study (four trials) was to determine if an in ovo injection with Bifidobacterium saeculare (B2-2, B3-4) and/or lactic acid bacteria (LAB18, LAB46) at d18 of embryogenesis reduced Enterococcus and Gram-negative bacterial colonization in the gut at hatch. An environmental challenge model was used to simulate microbial contamination in large-scale hatch cabinets in a laboratory setting. In all trials, gut homogenates obtained from chicks at hatch were plated to enumerate relevant bacterial populations. Performance was evaluated in trials two and four. The top treatments in trial one were selected for further testing in trials 2–4. The significance level for all analyses was set at p < 0.05. A meta-analysis of gut bacterial recovery for trials 2–4 revealed that the administration of probiotic treatments increased LAB and/or bifidobacteria at hatch compared to non-treated groups. LAB46 + B2-2 was more effective at reducing Gram-negative bacteria and Enterococcus in the gut compared to other probiotic treatments. All treatments improved d14 BW and d0–14 BWG compared to non-treated groups. These results indicate that exposure to beneficial bacteria during late embryogenesis can prevent colonization by opportunistic pathogens associated with contamination in commercial hatch cabinets and may also improve early performance in broiler chickens. Full article

Aromatase, a crucial enzyme for estrogen synthesis, plays a vital role in gender determination and differentiation. This study aimed to establish an inducible knockout model of the chicken CYP19A1 gene, which encodes aromatase, to support gender control in chickens. We selected the most efficient sgRNA target site and constructed an inducible knockout model based on the Tet-on system. The knockout efficiency reached 80% with 20 μg/mL DOX induction in vitro. The encapsulation of the plasmid with PEI and injection into eggs achieved a knockout efficiency of 45% in ovo. qRT-PCR analysis revealed a significant downregulation of female-related genes (CYP19A1, FOXL2, ESR1) and upregulation of male-related genes (DMRT1, SOX9, AMH) in female chicken embryos after induction. Western blotting showed decreased protein expression of CYP19A1 and FOXL2, and increased SOX9 expression in female embryos post-DOX induction. Elisa detection further confirmed lower estradiol levels in the gonads of induced female embryos compared to normal and non-induced females. These findings demonstrate the successful establishment of an inducible knockout system for the CYP19A1 gene in chickens, providing theoretical and technical support for the creation of new breeding materials for gender control. Full article

As a consequence of the European Union introducing the prohibition of supplying antibiotic growth promoters (AGPs) in diets in 2006, antibiotic alternatives for poultry feed have become one of the most central issues. In general, probiotics and prebiotics are highly effective additives that improve host health and prevent pathogen colonization by modulating immune functions, altering the intestinal microecology, and enhancing digestion. However, the specific situations in which probiotics or prebiotics should be used still require further research. In addition, the advanced applications of probiotics and prebiotics, such as in ovo injection, also need to be investigated to improve the host performance. In the following review, we summarize various probiotic and prebiotic supplementation methods and compare the specific conditions for their use to improve poultry production management. Full article

Exploring how early-life nutritional interventions may impact future generations, this study examines the inter- and transgenerational effects of in ovo injection of bioactive compounds on gene expression in the cecal tonsils and cecal mucosa using a chicken model. Synbiotic PoultryStar^® (Biomin) and choline were injected in ovo on the 12th day of egg incubation. Three experimental groups were established in the generation F1: (1) a control group (C) receiving 0.9% physiological saline (NaCl), (2) a synbiotic group (SYN) receiving 2 mg/embryo, and (3) a combined synbiotic and choline group (SYNCH) receiving 2 mg synbiotic and 0.25 mg choline per embryo. For the generations F2 and F3, the SYN and SYNCH groups were each divided into two subgroups: (A) those injected solely in F1 (SYNs and SYNCHs) and (B) those injected in each generation (SYNr and SYNCHr). At 21 weeks posthatching, cecal tonsil and cecal mucosa samples were collected from F1, F2, and F3 birds for transcriptomic analysis. Gene expression profiling revealed distinct intergenerational and transgenerational patterns in both tissues. In cecal tonsils, a significant transgenerational impact on gene expression was noted in the generation F3, following a drop in F2. In contrast, cecal mucosa showed more gene expression changes in F2, indicating intergenerational effects. While some effects carried into F3, they were less pronounced, except in the SYNs group, which experienced an increase compared to F2. The study highlights that transgenerational effects of epigenetic modifications are dynamic and unpredictable, with effects potentially re-emerging in later generations under certain conditions or fading or intensifying over time. This study provides valuable insights into how epigenetic nutritional stimulation during embryonic development may regulate processes in the cecal tonsils and cecal mucosa across multiple generations. Our findings provide evidence supporting the phenomenon of epigenetic dynamics in a chicken model. Full article

Poultry production systems are usually exposed to important infections that could be prevented by vaccination programs. Conventional methods of vaccination such as drinking water; spray, eye, or nose inoculation; and injection are usually given after hatching and have many disadvantages. Therefore, there is a great need for searching of alternative ways for vaccination process. In ovo vaccination technology is now regarded as an alternative approach to post-hatch vaccination in modern poultry operations. This technique is effective, fast, provides uniform vaccine dosing and delivery, is suitable for massive production, and reduces labor costs. Routine in ovo vaccination is applied during the late stage of embryonic development between days 17.5 and 19.25 of egg incubation. The best route of inoculation of the vaccine is in the amniotic fluid or in the embryo’s muscles, without causing any hatchability or chick quality losses. Accordingly, the inoculation site, the age of the embryos and breeders, presence of maternal antibodies, and the sanitation of equipment’s and the environment during the vaccination process affect the efficiency of the in ovo vaccination technique. In ovo vaccination technology is currently applied for vaccination against several economically important viral diseases such as Newcastle, infectious bursal disease, Marek’s disease, infectious laryngotracheitis, infectious bronchitis, avian influenza, and avian metapneumovirus. Moreover, vaccines used for prevention of mycoplasmosis and coccidiosis could be applied in ovo instead of in post-hatching application. It can be concluded that in ovo vaccination is a rapidly growing trend of vaccine technology, and it can replace post-hatching vaccination conventional methods. Full article

Cardiovascular diseases such as myocardial infarction or limb ischemia are characterized by regression of blood vessels. Local delivery of growth factors (GFs) involved in angiogenesis such as fibroblast blast growth factor-2 (FGF-2) has been shown to trigger collateral neovasculature and might lead to a therapeutic strategy. In vivo, heparin, a sulfated polysaccharide present in abundance in the extracellular matrix (ECM), has been shown to function as a local reservoir for FGF-2 by binding FGF-2 and other morphogens and it plays a role in the evolution of GF gradients. To access injectable biomaterials that can mimic such natural electrostatic interactions between soluble signals and macromolecules and mechanically tunable environments, the backbone of agarose, a thermogelling marine–algae-derived polysaccharide, was modified with sulfate, phosphate, and carboxylic moieties and the interaction and release of FGF-2 from these functionalized hydrogels was assessed by ELISA in vitro and CAM assay in ovo. Our findings show that FGF-2 remains active after release, and FGF-2 release profiles can be influenced by sulfated and phosphorylated agarose, and in turn, promote varied blood vessel formation kinetics. These modified agaroses offer a simple approach to mimicking electrostatic interactions experienced by GFs in the extracellular environment and provide a platform to probe the role of these interactions in the modulation of growth factor activity and may find utility as an injectable gel for promoting angiogenesis and as bioinks in 3D bioprinting. Full article

Effects of in ovo and dietary sources of calcidiol (25(OH)D₃), combined with Marek’s disease vaccine (MDV), on the expression of genes involved with the antioxidant activity, muscle deposition, and immunity in the pectoralis major (P. major) muscle and spleen of 40 d of age (doa) broilers were investigated. The in ovo treatments were as follows: (1) non-injected; (2) the injection of 50 μL of commercial MDV, (3) MDV + 1.2, or (4) 2.4 μg of 25(OH)D₃. All birds received either a commercial diet containing no supplemental 25(OH)D₃ (control) or the same diet supplemented with an additional 69 µg of 25(OH)D₃ per kg of feed (Hy-D diet). At 40 doa, the pectoralis major (P. major) muscle and spleen of 48 birds (six replicates per diet x in ovo treatment combination) were collected. When compared to un-supplemented commercial diet-fed birds, in birds that were fed the Hy-D diet, the expression of the TGF-β4 gene in the spleen and P. major muscle, and the GSH-P1, GSH-P7, SOD2, MyoG, MyoD1, and Pax3 genes in the P. major muscle were up-regulated, whereas the expression of the IL-1β, IL-8, and CYP24A1 genes in the spleen and P. major muscle were down-regulated. Nevertheless, birds that received any of the in ovo injection doses of 25(OH)D₃ exhibited a higher expression of the IL-10, TGF-β4, and CYP27B1 genes in the spleen and P. major muscle. Furthermore, in comparison to the MDV-injected control group, the CAT, MyoD1, and Pax3 genes in the P. major muscle were up-regulated, and the expression of the INF-γ, IL-1β and CYP24A1 genes in the spleen and the IL-8, and IL-1β genes in the P. major muscle were down-regulated. In conclusion, a significant improvement in the expression of genes responsible for enzymatic antioxidant activity, protein synthesis, and inflammatory reactions in 40-day-old broilers occurred in response to in ovo and dietary supplemental 25(OH)D₃, and supplemental 25OHD₃ provided via either route was used to enhance the expression of genes linked to vitamin D activity (CYP27B1, CYP24A1). Full article

Background: In ovo stimulation introduces bioactive compounds, such as prebiotics, probiotics, or synbiotics into incubating eggs to enhance gut health and immune system development in chickens. This study aimed to determine the genetic and environmental effects modulating responses to in ovo stimulation in commercial broilers and Green-legged Partridge-like (GP) native chickens. Methods: Eggs were stimulated on day 12 of incubation with prebiotics (GOS—galactooligosaccharides), probiotics (Lactococcus lactis subsp. cremoris), or synbiotics (GOS + L. lactis), with controls being mock-injected. Hatched chicks were reared in group pens and challenged with lipopolysaccharide (LPS) on day 42 post-hatching. Cecal tonsils (CT) and spleens were harvested 2 h post-challenge. RT-qPCR was used to analyze the relative gene expression of cytokine genes: IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12p40, and IL-17. Results: The results show that genotype influenced the expression of all immune-related genes, with broiler chickens exhibiting stronger innate inflammatory responses than native chickens. LPS induced both mucosal (CT) and systemic (spleen) immune responses in broilers but only systemic (spleen) responses in native chickens. Conclusions: In ovo stimulation had less of an impact on cytokine gene expression than LPS challenge. Broilers expressed higher inflammatory immune responses than GP native chickens. Full article

Stress in birds disrupts the homeostasis of the organism, leading to an inability to neutralize reactive oxygen species. Taurine, an effective antioxidant, affects various cellular mechanisms, including cation modulation, protein phosphorylation, and cell proliferation. The aim of the study was to evaluate the effect of colloid with taurine applied in ovo to Albumin on embryonic development, oxidative stress indicators and the content of bioactive peptides—carnosine and anserine—in the pectoral muscle. The research materials were eggs of the parent flock (Ross 308) divided into four groups (K (without injection), T50-concentration of taurine hydrocolloid 50 ppm (mg/L); T100-colloid concentration 100 ppm (mg/L) taurine; T500-colloid concentration of 500 ppm (mg/L) taurine). The experimental solutions were injected in an amount of 0.3 mL into egg white. Eggs were incubated under standard incubation conditions. The addition of 100 and 500 ppm taurine had a highly significant (p = 0.001) effect on the plasma antioxidant potential in chicks. The level of anserine increased with increasing concentrations of taurine. These changes were highly significant (p = 0.007). The level of anserine in the T2 and T3 groups was determined to be 2.5 times higher than in the pectoral muscles of embryos not treated with taurine colloid. An analysis of the results showed that the administration of an increased dose of hydrocolloid with taurine increased the content of carnosine and anserine in the pectoral muscle. Colloid with taurine applied in ovo to chicken white egg reduces oxidative stress and increases homeostasis of the organism. Full article