Table 2.
Effect of probiotics, prebiotics, and synbiotics injected in ovo on gut health and growth performance.
| Bioactive Compound | Description and Dose | Site and Time of Injection | Findings | Ref. |
|---|---|---|---|---|
| Probiotics alone or in combination | 1. Marek’s Disease (HVT) vaccination as a control group. 2. L. animalis (∼106 cfu/50 μL). 3. E. faecium (∼106 cfu/50 μL). 4. L. animalis + E. faecium (∼106 cfu & ∼106 cfu/50 μL each). |
Amnion on day 18 of incubation | The length, weight, and pH of gastrointestinal tissue were affected by in ovo probiotic, resulting in increased FCR from days 7 to 14. | [147] |
| Synbiotic (S) | S1. (Lactobacillus salivarius 105 cfu + 2 mg galactooligosaccharides (GOS))/egg S2. (Lactobacillus plantarum 105 cfu + 2 mg raffinose)/egg |
Amnion on day 18 of incubation | S2 up-regulated expression of genes involved in metabolic pathways | [138] |
| Prebiotic | Extract of Laminaria species of seaweed 0.88 mg/egg. | Air cell on day 12 of incubation | On day 42 of age, there was no significant effect of prebiotic injection on the growth performance of broiler chickens. In ovo treatment showed a significant increase in villi width and crypt depth on d 21 of age. Prebiotics injected in ovo impaired villus height, width, and surface area in the duodenum compared to the control group. |
[148] |
| Prebiotics | Stachyose (1. 5% and 2. 10%/mL) Raffinose (3. 5% and 4. 10%/mL) |
Amnion on day 17 of incubation | There was a significant increase in the relative expression of brush border membrane functioning proteins and villus surface area, as well as a reduction in the relative expression of Fe-related proteins in birds treated with probiotics. Probiotics significantly lowered the relative abundance of harmful bacteria while enhanced that of probiotics. Fe bioavailability, brush border membrane function, and gut microbiota were all positively influenced. |
[149] |
| Prebiotic | Trans-galactooligosaccharides 3.5 mg/egg | Air cell on day 12 of incubation | Prebiotics improved growth performance and carcass weight of chickens at six weeks of age. Prebiotics reduced severity of intestinal lesions and oocyst excretion induced by natural infection with Eimeria. | [100] |
| Prebiotics and synbiotics | Inulin (1.76 mg), trans-galactooligosaccharides (0.528 mg), (1.76 mg inulin + 1000 cfu L. lactis ssp. lactis), and (0.528 mg trans-galactooligosaccharides + 1000 cfu L. lactis ssp. cremoris) | Air cell on day 12 of incubation | No significant effects of probiotics and synbiotics were observed on FCR. However, trans-galactooligosaccharides and inulin + Ls lactis subsp. lactis significantly increased final body weight of treated chickens. | [150] |
| Probiotic | Bacillus subtilis fermentation extract 10 × 106 cfu/egg | Amnion on day 18.5 of incubation | In ovo administration of the probiotic improved intestinal morphology without impairing hatch performance or gut homeostasis. | [151] |
| Probiotic | Bacillus spp. base probiotic 107 cfu | Amnion on day 18 of incubation | Probiotics administered in ovo decreased the severity of virulent E. coli horizontal transmission and infection in broiler chickens during the hatching period. | [21] |