Spirulina supplementation effects on small ruminants performance and product attributes: a meta-analysis

The research aims to conduct a meta-analysis evaluating the nutritional benefits of Spirulina supplementation on growth performance, rumen function, antioxidant status, blood biochemistry, fatty acid profile, meat quality, and eating quality in small ruminant, specifically goats and sheep.

A systematic review and meta-analysis were conducted to determine the impact of Spirulina supplementation on various aspects of small ruminant performance and product attributes. Electronic databases (Scopus, PubMed, and Google Scholar) were searched for relevant studies published between 2012 and 2023. From the 350 identified studies, 24 matched the inclusion criteria of original research. A meta-analysis was performed using OpenMEE software. Publication bias was assessed using the precisioneffect test (PET)-precision-effect estimate with standard errors method and Rosenthal's fail-safe N analysis, visualised through PET regression plots in JASP software. Standardised mean differences between Spirulina-supplemented and control groups were calculated to determine the effect magnitude.

Meta-analysis show that Spirulina supplementation significantly enhances growth performance, meat quality, and antioxidant status in small ruminants compared to controls. Supplementation increases average daily gain and reduces feed conversion ratio. Additionally, Spirulina supplementation elevates antioxidant enzyme activities, including catalase, glutathione peroxidase, glutathione, and superoxide dismutase. Meat quality parameters, such as fat melting point, intramuscular fat percentage, and pH, are also positively affected. Blood biochemistry markers, including alanine transaminase, aspartate transaminase, cholesterol, haemoglobin, low-density lipoprotein, total protein, urea, and white blood cell counts, remain within normal physiological ranges. Moreover, Spirulina supplementation favorably alters fatty acid composition, increasing the proportion of eicosapentaenoic acid and decreasing the proportion of palmitic acid. Supplementation duration ranged from 14 to 182 days, with doses between 0.014 to 2.14 g/kg body weight/day.

Spirulina supplementation has potential effects on small ruminant productivity, especially growth performance, health and meat quality. Spirulina can be a valuable dietary addition for small ruminant. Further research is warranted to optimise supplementation strategies and understand underlying mechanisms.