Table 1 Different categories of alternatives to antibiotics in poultry production

Probiotics

10⁴–10⁹ CFU bacteria

• Improve homeostasis of bacteria in intestinal microbiota

• Inhibit pathogenic bacteria colonization

• Improve growth performance of broilers

• Improve/Strengthen immunity

[34,35,36,37]

Prebiotics

1–10 g/kg feed

• Inhibit pathogenic bacteria colonization

• Improve digestibility

• Catalyze the growth of healthy bacteria

[35, 38, 39]

Organic acids

0.5–3 kg/t feed; acidify water @ 5%

• Improve beneficial bacteria populations

• Reduce pH to aid in digestion and reduce pathogenic bacteria

[18, 40,41,42,43,44]

Phytochemicals

0.3–60 g/kg feed

• Antioxidant

• Antimicrobial

• Antifungal

• Anti-inflammatory

• Anti-parasitic

[8, 45,46,47]

Vaccines

Varies by vaccine type

• Significantly improves immunity

• Target-specific immunity

[19, 48]

In-feed enzymes

300–500 g/t feed

0.5–1 g/L water

• Improve digestibility, performance

• Improve feed intake and body weight gain

[49,50,51,52]

Essential oils

0.1–0.5 g/kg feed

• Improve digestion

• Improve blood circulation

• Exhibit antioxidant properties

• Reduce prevalence of pathogenic bacteria

[53, 54]