Abstract

Objectives: This study was aimed to evaluate the effects of dietary supplementation with the microalgae Arthrospira platensis (Ap) and Chlorella vulgaris (Cv) on growth performance, oxidative stress, immune-related cytokines gene expression, cecal fermentation, microbial population, and protein profile changes in growing rabbits.
Materials and Methods: Seventy-five male rabbits aged five-week were randomly allocated to five groups (n = 15). The control group received a basal diet without supplementation, whereas the remaining four groups were received basal diets supplemented with Ap or Cv at levels of 300 mg/kg or 500 mg/kg diet for 56 days.
Results: Phytochemical analysis revealed that both microalgae were rich in bioactive compounds including flavonoids, terpenoids and tannins exhibiting strong antioxidant activity. Dietary supplementation with Ap and Cv significantly improved BWG and FCR, while decreasing feed consumption. Oxidative stress markers, including malondialdehyde and hydrogen peroxide, were significantly decreased in algal-supplemented groups, accompanied by enhanced antioxidant status. Immune responses were favorably modulated through the upregulation of anti-inflammatory cytokines, particularly (IL-10 and IL-4). In addition, dose-dependent changes in protein expression profiles were observed in serum, liver and spleen tissues. Cecal fermentation parameters were improved, as evidenced by increased total volatile fatty acids, acetic and propionic acids, as well as Lactobacillus spp., along with reduced NH₃-N and pathogenic bacterial populations of E. coli, Staphylococcus spp., Enterococcus spp., and total coliforms (p < 0.05).
Conclusions: Dietary supplementation with A. platensis and C. vulgaris improves growth performance, antioxidant capacity, immune function, and cecal health in growing rabbits, supporting their use as feed additives.

Key words: Performance; immune response; gene expression; Spirulina platensis; Chlorella vulgaris; cecal microbiota; rabbits