Technical Bulletin: Utilization of AquaBeads® for Administering AviPro® Megan® Egg Salmonella Vaccine in Turkey Poults

Background

This study conducted by the University of Arkansas Division of Agriculture investigated the effectiveness of AquaBeads® as a vehicle for administering the AviPro® Megan® Egg Salmonella vaccine to day-of-hatch turkey poults. The trial evaluated vaccine delivery methods’ impact on body weight (BW), body weight gain (BWG), mortality, and Salmonella colonization.

Experimental Design

The study used 400 day-of-hatch turkey poults (hens) sourced from a commercial hatchery. Upon arrival, poults were wing-banded, individually weighed, and randomly allocated into one of four treatment groups (100 poults per group) with six replicate cages per treatment (10 poults per cage). Each group was assigned a distinct vaccination or vehicle treatment:

Group 1: Non-vaccinated, non-treated control. Poults received feed without AquaBeads® or vaccine exposure.

Group 2: Vaccinated control receiving the AviPro® Megan® Egg vaccine via oral gavage (0.25mL/poult) immediately after placement. Poults were then placed in chick boxes with feed only.

Group 3: Vaccinated using GelPac as a vehicle. The vaccine was applied via a spray to the poults per manufacturer guidelines. Poults were temporarily housed in chick boxes (100 poults/box) where they were allowed to preen to consume the vaccine.

Group 4: Vaccine added to AquaBeads® and mixed per manufacturer instructions. AquaBeads® were applied as a top dressing at a rate of 1.0g/poult (25g total) to feed flats within the chick boxes (25 poults per box). Poults were allowed to consume the AquaBeads® before being transferred.

Key Procedures

• To minimize cross-contamination, Group 1 (non-vaccinated control) was handled separately.
• For Groups 3 and 4, products (GelPac spray or AquaBeads®) were consumed before transferring poults to replicate cages.
• Poult surface temperatures were monitored in Group 3 to account for any potential chilling effect from GelPac application.
• CFU of the vaccine was verified after preparation by sampling mixed products (n=5, 1g per sample in 9mL saline) and performing drop plating on selective and non-selective agar.

Salmonella Analysis

At day 5, cecal and liver/spleen samples were aseptically collected from two poults per cage (12 poults per treatment). Samples were analyzed using microbiological methods, including enrichment in tetrathionate broth, plating on XLT-4 agar, and serotyping for S. Typhimurium to confirm vaccine presence.

Experimental Timeline

Day 0 (December 11): Poults were weighed, wing banded, and assigned to treatments. Groups 2-4 received their respective vaccine/vehicle treatments and were transferred to battery cages.

Day 5 (December 16): Cecal and liver/spleen samples were collected for Salmonella analysis.

Day 7 (December 18): Individual body weights were recorded, and the study was terminated.

Results

Body Weight (BW) and Body Weight Gain (BWG)

By day 7, all vaccinated groups (Groups 2-4) exhibited significantly higher BW and BWG compared to the non-vaccinated control (Group 1). However, no significant differences were observed among vaccinated groups. This indicates that the vaccine and vehicle methods did not impair early growth performance.

Group	Treatment	Average BW (g)	Average BWG (g)	Mortality (%)
1	Non-treated control	120.32 ± 2.38b	62.98 ± 2.00b	0/60 (0)
2	Vaccinated (oral gavage, 0.25mL/poult)	130.54 ± 2.43a	72.11 ± 2.26a	1/60 (1.66)
3	Vaccinated using GelPac (sprayed onto poults)	126.08 ± 2.27ab	69.30 ± 2.24a	1/60 (1.66)
4	Vaccinated using AquaBeads® (1.0g/poult)	127.23 ± 2.27ab	70.87 ± 2.14a	0/60 (0)

Values are expressed as mean ± standard error. a,b indicate significant differences within columns (P < 0.05).

Mortality

Mortality was low and not significantly different across treatment groups, indicating that neither the vaccine nor the delivery vehicles negatively affected poult survivability.

Salmonella Colonization (Cecum and Liver/Spleen)

By day 5, vaccinated groups (Groups 2-4) exhibited significantly higher Salmonella recovery in the cecum and liver/spleen compared to the non-vaccinated control (Group 1). Group 4 (AquaBeads®) had the highest Log10 CFU/g recovery from the cecum, significantly surpassing Groups 2 and 3. Recovery in the liver/spleen was consistent across vaccinated groups, confirming successful vaccine delivery.

Group	Treatment	Cecum (Log10 CFU/g)	Incidence (%)	Liver/Spleen (Log10 CFU/g)	Incidence (%)
1	Non-treated control	0.53 ± 0.36c	16.6	1.35 ± 0.20b	50
2	Vaccinated (oral gavage, 0.25mL/poult)	5.25 ± 0.21b	100*	2.70 ± 0.20a	100*
3	Vaccinated using GelPac (sprayed onto poults)	4.45 ± 0.70b	83.3*	2.70 ± 0.20a	100*
4	Vaccinated using AquaBeads (1.0g/poult)	6.53 ± 0.25a	100*	2.70 ± 0.20a	100*

Values are expressed as mean ± standard error. a,b,c indicate significant differences within columns (P < 0.05). Incidence data were analyzed using chi-square.

Thermal Imaging Results

Thermal imaging conducted post-treatment revealed important insights regarding the impact of vaccination methods on poult surface temperatures and potential stress indicators:

Normal Group (Control): Demonstrated stable surface temperatures, indicating baseline conditions for comparison.

GelPac Group: Thermal images indicated noticeable temperature variations, suggesting potential chilling or stress from the applied spray, which can have implications for animal welfare.

AquaBeads® Group: Thermal imaging indicated stable poult and environmental temperatures similar to control conditions, confirming minimal stress and validating AquaBeads®' non-wetting characteristic and suitability for stress-free vaccine delivery.

Conclusion

This study demonstrates that AquaBeads® can effectively deliver the Megan Egg® vaccine to day-of-hatch turkey poults without compromising growth performance or livability. The AquaBeads® vehicle showed comparable efficacy to oral gavage and GelPac spray methods, with higher Salmonella recovery in the cecum, indicating effective vaccine delivery. Future studies should investigate the long-term impacts of AquaBeads® and optimize administration protocols for broader commercial application.

This research study was conducted at the University of Arkansas, Department of Poultry Science by Danielle Graham, Ph.D., Assistant Professor – Parasitology.