Newcastle Disease ND in Chickens: Probiotic Schedule for Each Rearing Phase

Newcastle Disease (ND) is a highly contagious viral disease in chickens, causing significant economic losses for broiler farmers. Mortality rates can reach 90% in velogenic cases. Although vaccination is the mainstay, gut health management through probiotics has been proven to strengthen mucosal immunity and suppress secondary infections. This article presents the administration schedule of Broiler Probiotic Formula from Biosolution for each rearing phase — starter, grower, and finisher — as an integrated ND prevention strategy.

Why Probiotics Are Effective for ND Prevention in Broilers?

Probiotics work through several mechanisms relevant to combating ND. First, competitive exclusion: probiotic bacteria such as Lactobacillus acidophilus and Bacillus subtilis compete with pathogens (including ND virus and secondary bacteria like E. coli, Salmonella, Clostridium) for nutrients and adhesion sites in the gut. Second, lactic acid production by L. acidophilus lowers gut pH, creating an unfavorable environment for pathogens. Third, Bacillus subtilis produces digestive enzymes (protease, amylase, lipase) that improve feed digestibility, allowing more energy to be allocated for immune response. Fourth, probiotics modulate mucosal immunity by increasing IgA secretion, strengthening the gut barrier, and activating immune cells such as macrophages and dendritic cells. With a healthy gut, chickens are more resistant to ND virus attack and recover faster if infected.

Starter Phase (1–14 Days): Building Immunity Foundation

The starter phase is a critical period because the chicken's immune system is still immature. Early probiotic administration is highly recommended. For Biosolution's Broiler Probiotic Formula, the dosage in this phase is 1 ml per liter of drinking water or 2 ml per kg of feed, given daily in the morning after feeding. The product composition includes Lactobacillus acidophilus which quickly colonizes the gut, Bacillus subtilis which produces enzymes to aid digestion of high-protein starter feed, and Bacillus coagulans which forms heat-resistant spores, remaining stable even when mixed with feed. In this phase, probiotics help suppress colonization of Salmonella and E. coli, which often cause diarrhea and high mortality. Studies show that probiotic administration from DOC can increase antibody titers after ND vaccination (study in Poultry Science, 2021). Ensure drinking water is clean and does not contain excess chlorine that could kill probiotics.

Grower Phase (15–28 Days): Maintaining Microbiota Balance

Entering the grower phase, chickens begin to consume large amounts of feed and muscle growth increases. The risk of ND infection remains, especially if booster vaccination is not optimal. In this phase, probiotic frequency is reduced to 3 times per week (e.g., Monday, Wednesday, Friday) with the same dosage (1 ml/L drinking water or 2 ml/kg feed). The goal is to maintain beneficial bacterial populations in the gut without burdening operational costs. Spore-forming Bacillus coagulans is very advantageous in this phase because it withstands the feed pelleting process. Additionally, enzymes from Bacillus subtilis help break down higher fiber content in grower feed, improving energy and protein digestibility. With FCR improving by 8–12%, farmers can save on feed costs. Probiotics also suppress Clostridium perfringens, which causes necrotic enteritis often appearing in the grower phase due to stress or feed changes.

Finisher Phase (29–35 Days): Optimizing Final Weight and Meat Quality

The finisher phase is the final stage before harvest. The main target is achieving optimal body weight with efficient feed conversion. Probiotic administration remains 3 times per week until 2–3 days before harvest (to meet withdrawal regulations if any). The dosage does not change. In this phase, probiotics help maximize nutrient absorption, increasing average daily gain (ADG) by 5–10%. More importantly, probiotics reduce pathogenic bacterial populations in the gut, thereby reducing the risk of carcass contamination during slaughter. With no antibiotic residues (since this product is AGP-free), the chicken meat meets food safety standards and can be sold at a premium price. Some farmers report that probiotic administration until harvest results in denser meat and brighter color.

Case Study: Effect of Probiotics on Performance of ND-Vaccinated Broilers

An internal Biosolution study on 200 Cobb broilers vaccinated against ND at 4 and 18 days of age showed that the group receiving probiotics (according to the schedule above) had higher ND antibody titers on day 28 (average GMT 1:128 vs 1:64 in control) and lower mortality (2% vs 6%). The FCR of the probiotic group was 1.55, while the control was 1.70. Average harvest weight was 2.1 kg at 35 days, 150 grams heavier than the control. These data confirm that probiotics not only prevent ND but also increase productivity.

Proper Application of Probiotics for ND Prevention

For optimal probiotic performance, consider the following:

• Via drinking water: Use clean water without chlorine. If water contains chlorine, let it stand for 24 hours or use vitamin C to neutralize. Administer probiotics in the morning after chickens eat, ensuring water is consumed within 2–4 hours.
• Via feed: Spray probiotics evenly onto feed, mix thoroughly. For pelleted feed, spore-forming Bacillus coagulans will survive.
• Do not mix with antibiotics or disinfectants simultaneously. If chickens are sick and require antibiotic treatment, wait 2–3 hours after probiotic administration.
• Store probiotics in a cool place (4–8°C) to maintain bacterial viability. Ready-to-use liquid products have a shelf life of 6 months if refrigerated.

Integration with ND Vaccination and Other Management

Probiotics are not a substitute for vaccination but a complement. ND vaccination must still be carried out according to the program (active vaccine strain B1 or Lasota via drinking water or spray). Probiotics can be given 1–2 days after vaccination to reduce stress and strengthen immune response. Additionally, biosecurity management (disinfection of pens, traffic of people/equipment, stocking density) and good nutrition remain important. The combination of vaccination + probiotics + optimal management provides the best protection against ND.

Conclusion

Prevention of Newcastle Disease in broilers requires a holistic approach. Probiotics such as Biosolution's Broiler Probiotic Formula containing Lactobacillus acidophilus, Bacillus subtilis, and Bacillus coagulans provide natural protection through mechanisms of competition, acid production, enzymes, and immunomodulation. With the right administration schedule — daily in the starter phase, 3 times per week in grower and finisher — farmers can improve FCR by 8–12%, ADG by 5–10%, reduce mortality, and produce antibiotic residue-free meat. For maximum results, apply probiotics consistently and integrate with vaccination and biosecurity. Consult Biosolution's technical team for dosage and schedule adjustments for your farm via our WhatsApp.

FAQ

Can probiotics replace ND vaccination?

No. Probiotics cannot replace vaccination because vaccination provides specific immunity against the ND virus. Probiotics act as a support by strengthening non-specific gut immunity and suppressing secondary infections. The combination provides optimal protection.

How long should probiotics be given before they are effective against ND?

The effects of probiotics begin to appear after 3–7 days of regular administration, as bacteria need time to colonize the gut. For maximum protection, give probiotics from DOC until harvest. During an ND outbreak, probiotics should still be given to reduce symptom severity.

Can probiotics be mixed with ND vaccine in drinking water?

It is best not to mix them directly. Administer the vaccine first, then after 2–3 hours give probiotics. This avoids interactions that could reduce the effectiveness of the vaccine or probiotics.

Are probiotics safe for chickens sick with ND?

Probiotics are safe and even recommended to support recovery. However, if chickens have severe diarrhea or dehydration, ensure drinking water is available and consult a veterinarian. Probiotics can help restore gut microbiota balance after infection.

How should probiotics be stored to remain effective?

Store probiotics in a refrigerator at 4–8°C. Do not freeze. Avoid direct sunlight exposure. After opening, use within 30 days. Sealed products have a shelf life of 6 months from production.