Milk yield and milk fatty acid profile, blood metabolites, and rumen fermentation of lactating goats fed different levels of a combination of Spirulina-yeast

Abstract The combination of probiotics and microalgae has positive effects on animal productivity and health. This study investigated the impact of two levels of a combination of Limnospira platensis (Spirulina) and Saccharomyces cerevisiae (1:1) (SY) on milk yield, milk composition, and fatty acid profile, rumen fermentation, blood metabolites and immunity, and kids' performance of lactating goats. Thirty-six lactating goats were divided into three groups ( n = 12) to receive one of the three diets: the control diet without supplement, consisting of Alfalfa hay and a concentrate feed mixture (C); the control diet supplemented with 1% of the Spirulina-yeast combination based on dry matter (SY1); the control diet supplemented with 2% of the Spirulina-yeast combination (SY2). The SY1 group had a higher milk yield and milk polyunsaturated fatty acids, such as linoleic and α-linolenic, as well as lower saturated fatty acids, such as arachidic. The SY-supplemented goats had higher rumen propionic acid concentration and lower predicted methane production. In comparison, the SY1 group had higher total volatile fatty acids (VFA), isobutyric, butyric, and isovaleric acids. Moreover, blood cholesterol, urea, and alanine aminotransferase (ALT) decreased, while blood immunoglobulin IgG increased with both SY1 and SY2. Supplementing the lactating goats with a combination of live yeast and Spirulina at 1% of DM can enhance the rumen fermentation and performance.