Dose and time response of dietary supplementation with Schizochytrium sp. on the abundances of several microorganisms in the rumen liquid of dairy goats

Abstract Microalgae rich in polyunsaturated fatty acids (PUFAs), such as Schizochytrium sp., can be used in ruminant diets as feed additives to modify the rumen microbiome. However, limited in vivo studies exist dealing with their impact on the cellulolytic, methanogenic, and amylolytic microbes in the goat rumen. To address this gap, twenty-four goats were divided into four homogenous subgroups (n = 6 per group). The concentrate of the control group (CON) had no microalgae, while those of the treated groups were supplemented daily with 20 (ALG20), 40 (ALG40), and 60 (ALG60) g Schizochytrium sp./goat. The results showed a significant decline in the relative abundances of Ruminococcus flavefaciens, and Butyrivibrio proteoclasticus in the rumen fluid of ALG40-fed goats; while Fibrobacter succinogenes and Streptococcus bovis were significantly decreased in the ALG60 group compared to the CON group. The relative abundances of Methanobrevibacter spp. were significantly decreased in microalgae-fed goats. The relative abundances of Methanobacterium formicicum and Archaea showed a significant reduction in ALG40 and ALG60 groups, while methanogens and Methanomassiliicoccales portrayed a tendency to decrease (P