Evaluating bacterial colonization of a developing broiler embryo after in ovo injection with a bioluminescent bacteria

Effects of Embryo Microbial Contamination on ART and Neonatal Outcomes

Purpose

This study investigated the incidence and microbial etiology of embryo contamination in assisted reproductive technology (ART), and its influence on embryo development, pregnancy and neonatal outcomes.

Methods

A retrospective analysis was conducted on embryo contamination at the Reproductive Centre of the Third Affiliated Hospital of Guangzhou Medical University, between 2018 and 2021.

Results

In the period from 2018 to 2021, the average incidence of embryo contamination was 0.12%. Bacterial growth was observed in 39 cases, with a preponderance of Escherichia coli (20, 51.28%), Streptococcus agalactiae (7, 17.95%). The fertilization rate of contaminated embryos was 18.18% (Klebsiella pneumoniae) to 94.79% (S. agalactiae), the cleavage rate was 9.09% (Enterobacter cloacae) to 98.90% (S. agalactiae), and the available embryo rate of Day 3 was 0 (Klebsiella pneumoniae, Enterobacter cloacae) to 63.33% (S. agalactiae). Blastocyst formation rate was 3.23% (Proteus mirabilis) to 64.29% (Streptococcus mitis). E. coli contamination occurred mostly on Day 1, and S. agalactiae on Days 3 and 5. After rinsing and rescuing treatment, six healthy male babies were born.

Conclusion

E. coli and S. agalactiae were the most common bacterial embryo contaminants. Most microbial contamination can significantly decrease the fertilization rate. Embryo transfer after rinsing and continuing culture had no negative effect on neonatal outcomes, but there was an increased risk of early abortion due to E. coli contamination.

Research Note: Evaluating the vertical transmission potential of Salmonella Reading in broiler breeders

Salmonella Reading (S. Reading) recently emerged as a foodborne pathogen causing extensive human outbreaks in North America from consuming contaminated poultry products, mostly from turkeys. Understanding the transmission dynamics of this pathogen is crucial for preventing future outbreaks. This study investigated the ability of S. Reading to colonize the tissues and contaminate eggs of broiler breeders. We utilized 2 S. Reading strains, marked with bioluminescence gene: the outbreak strain RS330 and a reference strain RS326. We used 32 commercially sourced broiler breeder hens, 34 wk of age, randomly assigned to the 2 treatments (16 hens per strain). Each hen was intravaginally inoculated with 108 CFU of the respective strain on d 1 and was rechallenged on d 4. Eggs were collected daily postchallenge to recover bioluminescent S. Reading strains from the external eggshell surface and internal egg contents. On d 7 postchallenge, 10 hens from each treatment group were euthanized. Ovaries, oviducts, and ceca were aseptically collected to detect S. Reading colonization. Results showed that 70.5% (36 of 51) and 34.5% (19 of 55) of external eggshell surfaces, and 4.0% (2 of 50) and 1.8% (1 of 54) of the internal egg contents tested positive for the outbreak and nonoutbreak strains. Additionally, 40.0% of ovaries, 70.0% of oviduct, and 70.0% of ceca samples from the outbreak strain group, and 20.0% of ovaries, 70.0% of oviduct, and 80.0% of ceca samples from nonoutbreak strain group were positive. No significant difference (P = 0.05) was observed in all the findings among the strains except for the eggshell surface contamination. These findings suggest that S. Reading can effectively colonize reproductive tissues, translocate to the ceca, and contaminate the eggs of hens. Future research is needed to determine whether S. Reading can remain viable within the eggs throughout incubation and until hatching.

Embryonic injection of Lactobacillus plantarum PA01 alters the microbial diversity in the gastrointestinal tract of the broilers before and after hatching

The total number of intestinal microbiotas is low, and the intestinal tract develops rapidly and imperfectly at the embryonic stage. Embryonic period as a particular physiological stage is an important time window to explore how to regulate organismal health by probiotics. Therefore, this experiment was conducted to investigate the effect of embryonic injection of Lactobacillus plantarum PA01 at embryonic d 14 (E14) on the microbiome of the contents of the gizzard, cecum at embryonic d 20 (E20) and cecum at d 1 posthatch (D1) by 16S rRNA sequencing. Results showed that PA01 had no significant effect on broiler body weight and yolk sac weight at E20 and D1 (P > 0.05). PA-01 altered the Shannon index and β diversity of the gizzard at E20 (P < 0.05), increased the abundance of Firmicutes (P < 0.05), and decreased the relative abundance of Proteobacteria, Bacteroidota, and Actinobacteriota (P < 0.05). At the genus level of the microbiota, PA01 significantly increased the relative abundance of Lactiplantibacillus (P < 0.05). At 20 embryos, PA01 altered the α and β diversity indices (P < 0.05) and decreased the relative abundance of Salmonella (P < 0.05) of the cecal microbiota. The biomarkers of PA01 group were Lactobacillales, Blautia, Lachnospiraceae, and Asinibacterium. Embryonic injection of PA01 altered the E20 intestinal microbes. PA01 altered the β-diversity index of the 1-day-old cecum (P < 0.05), and there was no significant effect on microbial composition at the phylum and genus level (P > 0.05). LefSe analysis revealed that the biomarkers of the PA01 group were Lactobacillaceae, Lactiplantibacillus, Moraxellaceae, and Acinetobacter. Biomarkers in the Con group were Devosia, Bacillus, Nordella, Mesorhizobium, and Pseudolabrys. PA01 increased acetic acid in the gastrointestinal tract at E20 along with acetic and butyric acid in cecum of 1-day-old. In conclusion, embryo-injected L. plantarum PA01 altered the structure and metabolites of the microbial flora before and after hatching, in particular promoting the colonization of Lactobacillus.

Lactobacillus Plantarum injection at the embryonic stage alters the early growth performance and lipid metabolism of broilers by specific genera of bacteria

The main objective of this study was to explore the effects of broiler embryonic injection of Lactobacillus Plantarum on the growth performance, lipid metabolism of serum and liver, microbial diversity, and short-chain fatty acids of broiler intestines after hatching. On d 14 of incubation, 720 eggs of Arbor Acres were randomly divided into 4 experimental groups: no treatment control (C), Treatments injected with stroke-physiological saline solution (S), Supernatant of MRS medium culture of lactobacillus (Q) and Lactobacillus Plantarum spp. (J). The Hatch rate for each replicate was counted at 1 d of age. After hatching, each group were divided into six replicates of 10 broilers, and chicken from groups C, Q and J were reared until 14 d of age. The production performance of the three groups of chicks from 1 to 14 days was recorded and statistically analyzed separately. Serum and liver tissue were collected at 7 and 14 days of age for the detection of lipid metabolism index. 16S rDNA sequencing and Short-Chain Fatty Acids measurement of cecum contents were performed at 14 days of age. Overall, Lactobacillus injection significantly reduced feed conversion ratio (FCR) at 1-7 and 1-14 days of age, compared to the other 2 groups (P < 0.05). 16S rRNA sequencing results showed that the Roseburia and coprobacillus had a significantly positive correlation with body weight (P < 0.05). The Roseburia and lachnospira were significantly correlated with FCR (P < 0.05), and the absolute abundance of g_Anaerostipes as a biomarker in the J group was higher than in the C group (P < 0.05). The Q and J group increased the content of acetic, propionic, butyric, and total acid in the cecum contents (P < 0.05). In the jejunum, the J group increased the content of acetic, propionic, butyric, and total acids compared to the C and Q groups (P < 0.05). The J group increased the blood of total cholesterol (TC) content at 1 day of age and the triglyceride (TG) content of 7- and 14-day-old broilers (P < 0.05). and the J group raised the TG, TC, and high-density lipoprotein (HDL) level in the liver of 14-day-old broilers (P < 0.05). The J group reduced the liver's low-density lipoprotein (LDL) at 14 days of age (P < 0.05). In conclusion, the lactobacillus Plantarum injection at the embryonic stage alters lipid metabolism by short-chain fatty acids especially butyric produced by the specific bacteria of Roseburia and Anaerostipes.

Electromagnetic Force-Driven Needle-Free in Ovo Injection Device

Needle-free injections are mainly used for administering human or mammalian vaccines or drugs. However, poultry vaccines, in ovo injections to embryos, subcutaneous injections to chickens, and intramuscular injections are administered using needle injections. This article presents a new needle-free in ovo injection device method that uses push-pull solenoids to eject liquid jets, mainly for embryonic eggs of chickens. Furthermore, our study investigated the suitable jet pressures for using this method and the post-injection hatching rates in 18-day-old embryonic eggs. Using this method, we could deliver the liquid to the allantoic and amniotic cavities or the muscle tissue through the egg membrane of the air chamber using a jet pressure of ~6–7 MPa or ~8 MPa. After injecting 0.25 mL of 0.9% saline into 18-day-old Lohmann breed layer embryonic eggs and specific pathogen-free (SPF) embryonic eggs at a jet pressure of ~7 MPa, we observed hatching rates of 98.3% and 85.7%, respectively. This study’s electromagnetic needle-free in ovo injection device can apply vaccine or nutrient solution injection for embryo eggs and serve as a reference for future studies on needle-free in ovo injection automation systems, jet pressure control, and injection pretreatment processes.

In ovo Feeding as a Tool for Improving Performance and Gut Health of Poultry: A Review

Early growth and development of the gastrointestinal tract are of critical importance to enhance nutrients' utilization and optimize the growth of poultry. In the current production system, chicks do not have access to feed for about 48-72 h during transportation between hatchery and production farms. This lag time affects early nutrient intake, natural exposure to the microbiome, and the initiation of beneficial stimulation of the immune system of chicks. In ovo feeding can provide early nutrients and additives to embryos, stimulate gut microflora, and mitigate the adverse effects of starvation during pre-and post-hatch periods. Depending on the interests, the compounds are delivered to the embryo either around day 12 or 17 to 18 of incubation and via air sac or amnion. In ovo applications of bioactive compounds like vaccines, nutrients, antibiotics, prebiotics, probiotics, synbiotics, creatine, follistatin, L-carnitine, CpG oligodeoxynucleotide, growth hormone, polyclonal antimyostatin antibody, peptide YY, and insulin-like growth factor-1 have been studied. These compounds affect hatchability, body weight at hatch, physiological functions, immune responses, gut morphology, gut microbiome, production performance, and overall health of birds. However, the route, dose, method, and time of in ovo injection and host factors can cause variation, and thereby inconsistencies in results. Studies using this method have manifested the benefits of injection of different single bioactive compounds. But for excelling in poultry production, researchers should precisely know the proper route and time of injection, optimum dose, and effective combination of different compounds. This review paper will provide an insight into current practices and available findings related to in ovo feeding on performance and health parameters of poultry, along with challenges and future perspectives of this technique.

In ovo inoculation of an Enterococcus faecium-based product to enhance broiler hatchability, live performance, and intestinal morphology

Previous studies have suggested the use of probiotics, as alternative to antibiotics, to enhance broiler performance. The administration of probiotics in feed has been widely explored; however, few studies have evaluated the in ovo inoculation of probiotics. Therefore, the objective was to evaluate the impact of in ovo inoculation of different concentrations of GalliPro Hatch (GH), an Enterococcus faecium-based probiotic, on hatchability, live performance, and gastrointestinal parameters. Ross x Ross 708 fertile eggs were incubated, and on day 18, injected with the following treatments: 1) 50 μL of Marek's vaccine (MV), 2) MV and 1.4 × 105 cfu GH/50 μL, 3) MV and 1.4 × 106 cfu GH/50 μL, 4) MV and 1.4 × 107 cfu GH/50 μL. On the day of hatch, chicks were weighed, feather sexed, and hatch residue was analyzed. Male birds (640) were randomly assigned to 40 floor pens. On day 0, 7, 14, and 21 of the grow-out phase, performance data were collected. One bird from each pen was used to obtain yolk weight and intestinal segment weight and length. Hatchability was not impacted by any GH treatment (P = 0.58). On day 0, yolk weight was lower for all treatments than for MV alone. On day 0 to 7, feed intake was lower for 105 and 107 GH; the feed conversion ratio (FCR) was lower for all treatments than for MV alone (P = 0.05; P = 0.01, respectively). From day 14 to 21, the 107 GH treatment had higher BW gain (P = 0.05). For day 0 to 21, 107 GH had a lower FCR than MV alone (P = 0.03). On day 0, all GH treatments resulted in heavier tissues and longer jejunum, ileum, and ceca lengths than MV alone (P < 0.05). Spleen weight was higher for 105 and 107 GH than for MV alone. In conclusion, GH does not impact hatchability, and some concentrations improved live performance through the first 21 d of the grow-out phase. These improvements could result from the increased yolk absorption and improved intestinal and spleen morphology seen in this study.

Poultry feeds carry diverse microbial communities that influence chicken intestinal microbiota colonisation and maturation

Microbial colonisation of the gastrointestinal tract of newly hatched chicks starts at hatch, seeded from the immediate hatching environment, and quickly results in dense colonisation. The role of ecological factors in gut colonisation has been extensively investigated, as well as the role of micro- and macronutrients in supporting and selecting for bacterial species highly adapted for utilising those nutrients. However, the microbial community contained in poultry feed and its influence on colonisation and maturation of gut microbiota has not been directly addressed. In this study, we compared the microbiota found in poultry feed, with the microbiota of ileum, cecum and excreta, to identify substantial overlap in core microbiotas of the compared groups. We then investigated the microbiota present in raw feedstuffs: meat and bone meal, wheat, corn, canola, barley, soybean, millrun, sorghum, poultry oil, oats, limestone and bloodmeal from four geographically distinct feedstuff suppliers. Each of the feedstuffs had diverse microbial communities. The meat and bone meal and bloodmeal samples had the most complex and distinct microbial populations. There was substantial overlap in the phylogenetic composition found in the grain and seed samples: barley, canola, corn, millrun, oats, sorghum, soybean meal and wheat. Issues related to methodology, viability of microbial communities in the gut and feed, and the implications for biosecurity are discussed.