Spirulina (Limnospira platensis) is a microalga recognised for its rich nutritional composition and diverse bioactive compounds, making it a valuable functional food, feed, and therapeutic agent. This review examines spirulina’s chemical composition, including its high levels of protein, essential fatty acids, vitamins, minerals, and bioactive compounds, such as the phycocyanin pigment, polysaccharides, and carotenoids, in food, feed, and medicine. These compounds exhibit various biological activities, including antioxidant, anti-inflammatory, immunomodulatory, antiviral, anticancer, antidiabetic and lipid-lowering effects. Spirulina’s potential to mitigate oxidative stress, enhance immune function, and inhibit tumour growth positions it as a promising candidate for preventing chronic diseases. Additionally, spirulina is gaining interest in the animal feed sector as a promotor of growth performance, improving immune responses and increasing resistance to diseases in livestock, poultry, and aquaculture. Despite its well-documented health benefits, future research is needed to optimize production/cultivation methods, improve its bioavailability, and validate its efficacy (dose–effect relationship) and safety through clinical trials and large-scale human trials. This review underscores the potential of spirulina to address global health and nutrition challenges, supporting its continued application in food, feed, and medicine.

This review presents the chemical composition, bioactive properties, and diverse applications of Chlorella vulgaris, a green microalga widely recognized for its exceptional nutritional value and therapeutic potential. The study emphasizes the presence of key nutrients, including high-quality proteins, essential vitamins, minerals, and an array of bioactive compounds such as carotenoids, chlorophyll, and polysaccharides. These compounds have been shown to exhibit a wide spectrum of biological activities, including potent antioxidant, anti-inflammatory, immunomodulatory, antiviral, anticancer, antidiabetic, lipid-lowering, and detoxifying effects. The review explores the multifaceted applications of C. vulgaris in various sectors, including its growing role as a functional food ingredient, a nutraceutical supplement in animal feed, and a promising therapeutic agent for combatting chronic diseases. This paper also highlights its potential for enhancing immune responses, mitigating oxidative stress, promoting detoxification of heavy metals, and improving overall health outcomes. However, current limitations in clinical evidence surrounding its medicinal efficacy present challenges that need to be addressed. Furthermore, significant obstacles remain in scaling up C. vulgaris production, including optimizing cultivation techniques and improving bioavailability. Additionally, this review identifies crucial research gaps, particularly in optimizing cultivation techniques, improving bioavailability, and validating the clinical efficacy of C. vulgaris. By addressing these challenges, C. vulgaris holds significant promise in contributing to global health, sustainable nutrition, and environmental conservation efforts by serving as a source of protein and bioactive components for a growing population while simultaneously having a lower environmental impact and requiring fewer resources in production compared to traditional ingredients like soybean meal.

Chlorella vulgaris, a unicellular green microalga, has obtained significant attention due to its high protein content, abundance of bioactive compounds, and broad biotechnological potential. Used in nutraceuticals, pharmaceuticals, and functional foods, it is now gaining traction in cosmetics, biopharmaceuticals, and environmental applications. Recent advancements in fermentation technology, such as the development of high-density fermentation strategies, adaptive evolution of strains, and real-time monitoring systems, have greatly improved the efficiency, scalability, and sustainability of C. vulgaris production, enhancing bioavailability and product quality. This review explores developments in C. vulgaris fermentation, highlighting advancements in strain improvement through genetic engineering, metabolic optimization, mutagenesis, and adaptive evolution, alongside bioprocess engineering and the optimization of fermentation parameters. Key considerations include bioreactor design, downstream processing, and innovative monitoring technologies aimed at maximizing biomass yield and bioactive compound production. Emerging applications of fermented C. vulgaris across industries are also highlighted, along with future perspectives on scaling up production, addressing regulatory challenges, and ensuring biosafety. These insights provide a comprehensive outlook on the future of C. vulgaris fermentation in biotechnological applications.

Chlorella vulgaris (CV) is a microalga with considerable nutritional value, containing high levels of protein, carotenoids, and polyunsaturated fatty acids, which have the potential to positively influence the productive performance and egg quality of laying hens. CV emerges as a more sustainable ingredient than soybean meal (SBM) as it can be produced locally and with fewer inputs. In this regard, a study was conducted with 48 H&N Brown Nick strain laying hens, at 19 weeks of age, over a period of 16 weeks. The hens were divided into four treatments, with 12 replicates each. The treatments consisted of providing four different diets: a control diet based on corn and SBM without the inclusion of CV, and three other diets with partial substitution of SBM by 2.5, 5, and 10% of CV. The results showed that the inclusion of CV in the diets did not significantly affect feed intake, feed conversion ratio, or egg production (p > 0.05). In addition, moderate CV levels increased egg weight, while higher levels reduced it. Haugh units, yolk index, albumen index, egg surface area, specific density, and translucency were not affected (p > 0.05), while shell index and shell thickness were lower in the groups that received the CV (p < 0.0001). Yolk color improved significantly with increasing CV levels (p < 0.0001), with darker, more intensely colored yolks at higher CV concentrations. The results of this study suggest that the incorporation of CV in the diet of laying hens had a limited impact on performance parameters. In addition, CV supplementation can positively influence egg quality and yolk color, although careful consideration of optimal levels is necessary to avoid negative effects on other parameters.

The impacts of cumulative Chlorella vulgaris intake (proportion of microalga in the diet multiplied by the total feed consumed by each bird) on broiler carcass traits, meat quality and oxidative stability were reviewed to identify the optimal intake levels for maximising benefits. Our findings indicate that a cumulative intake of 8.73 g/bird significantly enhances thigh yield, while levels ranging from 8.73 to 401 g/bird optimise carcass weight and overall meat quality. However, higher cumulative levels may reduce carcass dressing percentage due to metabolic inefficiencies. Furthermore, C. vulgaris intake improves the oxidative stability of broiler meat by increasing antioxidant levels and balancing pro- and antioxidants. Including C. vulgaris in broiler diets boosts total carotenoid content, and antioxidant assays confirm that it enhances meat oxidative stability, with low to moderate cumulative intake levels (8.73 to 401 g/bird) providing the best balance of benefits. Optimal oxidative stability and antioxidant properties were observed at a cumulative intake level of 401 g/bird, showing significant improvements in meat antioxidant capacity. Higher levels may lead to diminishing returns or potential negative effects due to the digestibility issues of the microalga. Future research should refine intake models, understand the bioavailability of C. vulgaris nutrients and explore cost-effective methods to enhance its digestibility, to ensure its viability and sustainability as a feed additive.

This systematic review examines the effects of cumulative Chlorella vulgaris intake levels on broiler chickens, focusing on growth performance and systemic health markers. The review establishes a clear relationship between cumulative C. vulgaris intake and significant outcomes in poultry nutrition and health through a detailed analysis of various studies. The correlation analysis revealed that cumulative C. vulgaris intake levels ranging from 0.8 to 718 g/bird influenced growth rates and feed efficiency, following sigmoid models. Specifically, intakes of approximately 20 g/bird maximized final body weight (R² = 0.616, p < 0.001), cumulative body weight gain (R² = 0.627, p < 0.001) and daily weight gain (R² = 0.639, p < 0.001). The feed conversion ratio also improved with increasing C. vulgaris intakes up to this level, although this was non-significant (R² = 0.289, p = 0.117). In addition, similar cumulative C. vulgaris intake levels impacted plasma health markers in broilers, leading to reductions in triacylglycerols and cholesterol and improvements in immunoglobulin levels. These findings underscore the importance of carefully calibrated C. vulgaris supplementation strategies to optimise poultry growth and health without adverse effects. Future research should focus on refining C. vulgaris dosing guidelines and further exploring its long-term effects and mechanisms of action to enhance poultry health and production sustainability.