Effects of stage of broiler embryo development on coccidiosis vaccine injection accuracy, and subsequent oocyst localization and hatchling quality.

Control of coccidiosis in broiler chickens continues to pose challenges to commercial poultry producers, especially in an era of increased consumer demand for antibiotic-free broiler production. As a result, coccidiosis vaccines are now commonly used in rotation programs to achieve effective coccidiosis control. Inovocox EM1 vaccine (EM1) is a coccidiosis vaccine that allows for earlier immune acquisition through oocyst cycling, which reduces the effects of wild-type coccidia. The EM1 vaccine is administered to embryonated broiler hatching eggs between 18 and 19 D of incubation (doi). In the U.S., commercial broiler hatcheries vaccinate embryonated eggs at either 18.5 or 19 doi. However, it is unclear whether a difference in embryo age at the time of in ovo injection can impact the actual site of vaccine delivery. In addition, it is unclear where oocysts eventually become localized within the embryo following the in ovo injection of EM1. Therefore, the objective of this study was to determine the effects of stage of embryonic development on the actual deposition site of the EM1 vaccine oocysts when they are in ovo injected and to subsequently investigate the movement and eventual location of EM1 oocysts after in ovo injection. Because all eggs were injected at the same time, a 12-h difference in set time was a means to derive 18.5 and 19.0 incubation age of injection (IAN) treatments. The experimental design was a 3 injection treatment (noninjected, diluent-injected, and vaccine-injected) × 2 IAN factorial. There was a significant main effect of IAN on site of vaccine oocysts delivery, and subsequent hatching chick quality. Qualitative histological evaluation revealed the oral uptake of vaccine oocysts through the amnion, with their subsequent presence in the gizzard and intestinal lumen by 24 to 36 h postinjection. In conclusion, physiological development influenced the site of injection, and oocysts imbibed along with the amniotic fluid in late stage broiler embryos are subsequently transported to the gastrointestinal tract.

Investigating commercial in ovo technology as a strategy for introducing probiotic bacteria to broiler embryos.

Probiotics can improve broiler performance and reduce pathogens. Because the hatchery can be a source of contamination, delivering probiotics to the embryo before hatch is desirable. To date, probiotics have primarily been injected into eggs manually. Therefore, the objective of this study was to deliver various probiotic bacteria into broiler hatching eggs using an automated commercial in ovo injection system to evaluate hatchability of fertile eggs (HF). Three separate experiments were conducted using Lactobacillus acidophilus, Bacillus subtilis, or Bifidobacterium animalis. In each experiment, 7 treatments (non-injected control; dry punch control; diluent-injected control; and injections of 103 cfu, 104 cfu, 105 cfu, or 106 cfu of bacteria/50 µL of diluent) were evaluated using 10 replicates per treatment. For each experiment, 2,490 eggs were obtained from a commercial hatchery. Eggs were incubated under standard incubation conditions. At 10 d of incubation (doi), eggs were candled, and infertile eggs were removed. On 18 doi, all eggs were injected with the appropriate treatment using an automated in ovo injection system. Once all eggs were injected, they were transferred to hatching baskets and placed into the hatcher. On 21 doi, chicks were removed from the hatcher, counted, and weighed. Hatch residue analysis was conducted to determine infertile, early dead, mid dead, late dead, pipped, cracked, contaminated, and cull chick statuses of all unhatched eggs. Injecting L. acidophilus, even at a concentration as high as 106 cfu/50 µL, did not impact hatch residue analysis (P > 0.05). However, HF was significantly less for eggs treated with B. subtilis than for control eggs (P < 0.0001). For the non-injected control, HF was 91%, but as concentration of B. subtilis increased, HF decreased to as low as 1.67% for the 105 cfu treatment. Late deads, pipped, and contaminated egg percentages were higher, and chick BW was lower for B. subtilis treatment groups compared to controls. In conclusion, L. acidophilus and B. animalis but not B. subtilis, appear to be suitable candidates for in ovo injection as probiotics.

Impact of oral Lactobacillus acidophilus gavage on rooster seminal and cloacal Lactobacilli concentrations.

The use of antibiotics in poultry is being heavily scrutinized, therefore alternatives such as probiotics are being investigated. Lactobacilli spp. are a commonly used bacteria in formulating probiotics, and the addition of Lactobacilli to broiler diets has demonstrated increased growth rates, stimulated immune systems, and reduced pathogen loads in the gastro-intestinal tract ( GI: ) tract. However, previous research has shown that when rooster semen is directly exposed to Lactobacillus acidophilus (L. acidophilus) sperm quality is reduced. Therefore, the objective of the current study was to determine if oral administration of L. acidophilus increases the concentration of Lactobacilli in semen as well as the cloaca. A total of 30 roosters were used: 15 roosters were gavaged with 1X PBS (Control) and 15 roosters were gavaged with 10(7) cfu/mL of L. acidophilus (Treated). All roosters were gavaged for 14 consecutive days. Semen was collected on a 3 d interval, and cloacal swabs were collected on a 2 d interval, beginning on the first day prior to oral administration. Semen and cloacal swabs were serial diluted, and 100 µL of each dilution was then plated on Man, Rogosa, Sharpe ( MRS: ) agar plates. All plates were incubated for 48 h at 37°C under anaerobic conditions and counted. All Lactobacilli counts were first log transformed, then log transformed (day 0) pre-counts were subtracted from the log transformed day counts providing log differences for the analysis. Seminal Lactobacilli counts were not altered by treatments. However, the main effect of treatment (P = 0.026) for cloacal counts indicated that roosters gavaged with Lactobacilli yielded higher counts than the controls. Additionally, cloaca samples also demonstrated a treatment by day interaction trend (P = 0.082), where Lactobacilli was higher in the L. acidophilus gavaged roosters than the controls only on days 3, 5, 13, and 15. In conclusion, the addition of L. acidophilus to the male breeder diet over extended periods may increase concentrations of Lactobacilli in the cloaca even higher than the concentrations observed in this study. If Lactobacilli reaches high enough concentrations in the cloaca, then sperm quality may be impacted which could lead to poor fertility within the breeder flock.

Influence of 6 different intestinal bacteria on Beltsville Small White turkey semen.

The turkey industry relies totally on artificial insemination to continue and improve production. If something compromises the insemination process, such as contaminated semen, it becomes a detrimental loss to the industry. Bacteria have been found in broiler breeder males to reduce sperm motility. The Sperm Quality Index (SQI) is a quick method to determine avian sperm motility using the sperm quality analyzer (SQA). Therefore, the objective of this study was to determine if bacteria have an effect on turkey sperm motility using the SQA. For the experiment, one mL of pooled neat semen was collected from Beltsville Small White Turkey toms. Six intestinal bacteria, Bifidobacterium animalis, Campylobacter jejuni, Clostridium bifermentans, Escherichia coli, Lactobacillus acidophilus, and Salmonella enterica were grown overnight. For each bacterium, 4 treatments were made that consisted of exposing pooled semen to either saline, sterile broth, an overnight culture of each individual bacterium, or a centrifuged pellet of each bacterium re-suspended in saline. The experiment was repeated 3 times. Once the semen was exposed to the respective treatment, a portion was pulled into a capillary tube and placed into the SQA to obtain the SQI. Each treatment was evaluated at zero, 10, and 20 min creating a completely randomized design with a split plot over time. A pH reading also was taken at each time point. The results indicated that all broths containing bacteria immediately reduced turkey sperm motility. Sperm became practically immotile in overnight cultures of Clostridium, Bifidobacterium, or Lactobacillus However, there was a time by treatment interaction in the SQI for Campylobacter, Clostridium, E. coli, Salmonella, and Lactobacillus The pH of semen decreased upon exposure to Bifidobacterium and Lactobacillus No difference in pH was found when semen was exposed to E. coli, Campylobacter, Salmonella, or Clostridium treatments. In conclusion, the results reveal when turkey semen is exposed to different bacteria, sperm motility is immediately reduced, which could be possible from bacterial attachment or bacterial by-products providing an undesirable environment for sperm.