Avian coccidiosis, one of the most prevalent infections chickens globally, remains a main obstacle to the development of poultry industries in developing agricultural nations.
The two main approaches to managing Eimeria protozoa infections in commercial chicken production are anticoccidial drug administration and immunization with coccidial vaccines.
Additionally, nutritional additives such as prebiotics and probiotics have been developed to help maintain a healthy intestinal tract as a complementary technique to vaccination to prevent or reduce any potential side effects of vaccination as well as preventing entry of potentially harmful secondary pathogens.
A group of researchers in Egypt and Saudi Arabia conducted a trial to assess the anticoccidial potential of beneficial microorganisms and their derivatives (prebiotics and probiotics) against coccidia-vaccinal strains to prevent performance decline induced by early vaccination, promote immune development, and improve the vaccine’s ability to protect against coccidia challenge.
They reported their results in a recent issue of Poultry Science.
The study used 150 one-day-old chicks that were randomly divided into five groups with three replicates per group: negative control (unvaccinated, untreated and unchallenged), challenged control (unvaccinated, untreated and challenged), vaccinated control (vaccinated, untreated and challenged), V-PRO (vaccinated, probiotic-treated and challenged) and V-PRE (vaccinated, prebiotic-treated and challenged).
Vaccination groups received eye drops of the Fortegra vaccine on the first day of life. Probiotics and prebiotics were administered via drinking water to those respective groups between the first and 18th day of age. On day 21, a 25-fold dose of the vaccine was administered via crop gavage to challenge all birds except the negative control group.
In the post-vaccination period, vaccinated control and V-PRO groups had lower weight gains than negative controls and V-PRE groups. There were no differences in feed intake, and feed conversion ratios did not differ between groups for the three-week post-vaccination period.
The researchers reported that post-challenge, coccidia-vaccinated broilers administered probiotics or prebiotics continued to exhibit protection levels comparable to the vaccinated controls. In the two weeks post-challenge, the three vaccinated groups had improved bird performance and reduced oocyst shedding and lesion scores compared to challenged controls.
In the post-vaccination period, the V-PRE group had decreased average lesion scores compared to the unsupplemented vaccinated control group. The V-PRE and V-PRO groups had similar lesion scores at different intestinal regions.
Additive-supplemented birds demonstrated a reduction in oocyst excretion post-challenge with the V-PRO group having the lowest numerical excretion post-challenge compared with the challenged control group (but statistically similar to the other two vaccinated groups).
At day 21 post-vaccination, the vaccinated groups provided either probiotics or prebiotics showed non-significant changes in ileal bacterial counts compared to either the negative control group or the vaccinated control group.
The researchers noted that in this study, the growth performance of the vaccinated control group on day 21 post-vaccination was adversely affected, which may have been due to a decrease in plasma carotenoid levels, an imbalance of intestinal flora and an increase in gross lesion scores.
They concluded that giving additional probiotics or prebiotics to coccidia-vaccinated chickens during the first 18 days of life reduced the amount of intestinal damage and altered the cecal microbiota during the starter phase but did not enhance growth performance or profitability.
What does this mean for producers?
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Providing prebiotics or probiotics to coccidia-vaccinated chickens did not reverse the reduction in growth performance attributed to coccidiosis vaccination.
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Supplementing prebiotics or probiotics reduced intestinal damage and altered the cecal microbiota.
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Effectiveness of coccidia vaccines against coccidiosis challenge was not affected by additive supplementation.
The full paper, “The anticoccidial effects of probiotics and prebiotics on the live coccidia vaccine and the subsequent influence on poultry performance post-challenge with mixed Eimeria species,” can be found in Poultry Science and online here.
DOI: 10.1016/j.psj.2024.104283
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