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<0.10) in ALG20 and ALG40 groups compared to the CON group. In contrast, the relative abundance of Methanomicrobium mobile was significantly increased in the rumen of ALG60 goats. In conclusion, the supplementation of goat diets with 20 g Schizochytrium sp. might be considered an efficient nutritional strategy for methanogen inhibition in the rumen fluid, since selected methanogenic microbes were decreased, while rumen bacteria involved in feed fermentation were not considerably altered.

富含多不饱和脂肪酸（PUFA）的微藻，例如裂殖壶菌属（Schizochytrium sp。），可作为反刍动物饲料中的饲料添加剂，用于修饰瘤胃微生物组。但是，关于它们对山羊瘤胃中的纤维素分解，产甲烷和淀粉分解微生物的影响，存在有限的体内研究。为了解决这一差距，将二十四只山羊分为四个同质亚组（每组n = 6）。对照组（CON）的浓缩液没有微藻，而治疗组的浓缩液每天补充20（ALG20），40（ALG40）和60（ALG60）g裂殖壶菌属/山羊。结果表明，黄曲霉球菌和酪破蛋白破壁菌的相对丰度显着下降在ALG40喂养的山羊的瘤胃液中；而相比于CON组，ALG60组的琥珀酸纤维杆菌和牛链球菌明显减少。甲烷短杆菌属的相对丰度。微藻饲喂的山羊的血脂显着降低。相较于CON组，甲甲烷菌和古生菌的相对丰度显示ALG40和ALG60组显着减少，而产甲烷菌和甲烷甲烷菌显示出ALG20和ALG40组降低的趋势（P <0.10）。相反，Methanomicrobium mobile的相对丰度ALG60山羊的瘤胃中的蛋白含量显着增加。总之，在山羊日粮中添加20 g裂殖壶菌属菌种。可能被认为是抑制瘤胃液中产甲烷菌的有效营养策略，因为选择的产甲烷微生物减少了，而与饲料发酵有关的瘤胃细菌却没有发生很大变化。