Probiotic Supplementation in Rabbit Nutrition

Probiotic Supplementation in Rabbit Nutrition

• • Probiotic supplementation in rabbit nutrition** refers to the use of beneficial microorganisms or biologically active extracts—such as *Bifidobacterium*, *Saccharomyces cerevisiae* (yeast), and microalgae like *Spirulina platensis*—to improve digestive efficiency, metabolic function, immunity, and overall health in domestic and production rabbits (*Oryctolagus cuniculus*).

Overview

Probiotics and related feed additives have been studied in rabbits for their potential to enhance growth performance, nutrient utilization, and resistance to disease. These supplements are typically incorporated into **complete pelleted diets** formulated to meet National Research Council (NRC) and World Rabbit Science Association (WRSA) nutritional guidelines. Research suggests that probiotics can mitigate the negative effects of low-energy diets by improving feed conversion, promoting gut health, and supporting immune responses.

Historical Context

The use of pelleted diets in rabbit production began in the mid-20th century, with formulations evolving to balance digestible protein, fiber, fat, vitamins, and minerals. In recent decades, attention has shifted to functional feed additives such as probiotics, prebiotics, and microalgae to further optimize performance and welfare. Unlike hay-heavy feeding models promoted in some pet care circles, most controlled feeding trials use balanced pelleted diets as the nutritional base.

Shaheen et al. (2025) Study

A notable example is the 2025 study by Shaheen *et al.* published in *Frontiers in Veterinary Science*.\[1]

• **Design:** 100 male New Zealand White rabbits (5–13 weeks old) assigned to five groups: standard energy diet, low energy diet, low energy + *Bifidobacterium*, low energy + *Spirulina* extract, low energy + yeast extract.
• **Findings:**

 * *Spirulina* supplementation produced the highest final body weight and weight gain.
 * *Bifidobacterium* improved feed conversion ratio and reduced feed intake while maintaining growth.
 * All supplemented groups showed improved liver and kidney function (↑ total protein, albumin; ↓ ALT, AST, creatinine) and enhanced immunity (↑ IgA, IgG).
 * Thyroid hormone levels (T3, T4) increased in all probiotic groups, suggesting enhanced metabolic rate.

• **Conclusion:** Probiotic and biological additive supplementation in low-energy diets significantly improved rabbit growth performance, metabolic health, and immune function without adversely affecting carcass yield.

Nutritional Mechanisms

Probiotic and microalgae supplementation are thought to:

• **Enhance nutrient digestibility** through modulation of gut microbiota.
• **Provide bioavailable proteins and essential amino acids**, particularly in the case of *Spirulina*.
• **Stimulate immune responses** via increased immunoglobulin production.
• **Reduce oxidative stress and inflammation** through antioxidant compounds.

Implications for Rabbit Feeding

Evidence from controlled trials supports the inclusion of probiotics and functional additives in complete pelleted diets for optimal rabbit health and productivity. These results challenge feeding models heavily reliant on low-protein, high-fiber hay, as nutrient-dense pelleted diets with targeted supplementation yield superior performance outcomes in research settings.

See Also

• \[Rabbit nutrition]
• \[Pelleted feed]
• \[Microbiota in herbivores]
• \[Functional feed additives]

References

1. Shaheen, M.S., Allam, A.A., Abdel Monem, U.M., Bassiony, S.M., Khalil, B.A., Salah, A.S., Alawam, A.S., Rudayni, H.A., Elolimy, A.A., & Abass, K.S. (2025). Bifidobacterium, Spirulina, and Yeast extracts in low-energy diets for rabbits: effects on performance, hematology, lipid metabolism, hepatorenal function, immunity and hormones. *Frontiers in Veterinary Science, 12*, 1615203. [1](https://doi.org/10.3389/fvets.2025.1615203)

Species / Breed | Probiotic / Additive | Dose & Duration | Diet Type | Key Effects | Reference |

---------------------- | --------------------------------------------------------------------- | ------------------------------------------------------------ | -------------------------------------- | ------------------------------------------------------------------------- | ------------------------------------------------------------------ |

New Zealand White | *Bifidobacterium* | 1 mL/kg diet, 8 weeks | Low-energy pelleted diet (10.25 MJ/kg) | ↑ FCR, ↓ feed intake, ↑ IgA, improved kidney function | [Shaheen et al., 2025](https://doi.org/10.3389/fvets.2025.1615203) |

New Zealand White | *Spirulina platensis* extract | 2 mL/kg diet, 8 weeks | Low-energy pelleted diet | ↑ Body weight, ↑ IgG, ↑ albumin, ↓ AST/ALT, ↑ T3/T4 | Shaheen et al., 2025 |

New Zealand White | *Saccharomyces cerevisiae* extract | 2 mL/kg diet, 8 weeks | Low-energy pelleted diet | ↑ Protein & globulin, ↑ T3/T4, ↑ WBC, better liver function | Shaheen et al., 2025 |

Mixed domestic rabbits | *Bifidobacterium*, *Lactobacillus*, *Enterococcus*, *Bacillus cereus* | Commercial live tablet, during hepatic artery infusion chemo | Standard maintenance diet | Restored cecal microbiota structure, improved gut barrier and immunity | [Yan et al., 2024](https://doi.org/10.3390/biology13050327) |

Mixed breeds | *L. rhamnosus* GG, *B. animalis* BB-12, *S. boulardii* CNCM I-745 | 8-week oral dosing | Standard diet | ↑ Hematology & biochemistry profiles, ↑ body weight | [Kadja et al., 2021](https://doi.org/10.3390/biology10111194) |

New Zealand White | *B. animalis* BB-12, *L. plantarum* 299v | 8-week oral dosing post-obesity induction | Standard diet + high energy | Improved lipid metabolism, ↑ antioxidant status, improved organ histology | [Bouaziz et al., 2021](https://doi.org/10.3390/biology10020131) |

Meat rabbits | *Bacillus subtilis* | 5×10⁹ CFU/kg diet, 6 weeks | Standard pelleted diet | ↑ Immunity, ↑ disease resistance to Pasteurella multocida | [Guo et al., 2017](https://doi.org/10.3389/fimmu.2017.00354) |

Various | Active dry yeast (*S. cerevisiae*) | 0.12 g/kg diet, 6 weeks | Standard pelleted diet | ↑ Weight gain, improved FCR, stable carcass traits | Ezema & Eze, 2015 |

Laboratory rabbits | *B. longum* strains | Lab inoculation study | Controlled feed | Identified immunoreactive proteins with cross-species relevance | [Górska et al., 2016](https://doi.org/10.3389/fmicb.2016.01537) |