Investigators have previously found that sperm quality was not related to obesity indicators, such as body mass index (bmi), waist circumference, waist-hip ratio, girth ratio and serum lipid, but seminal plasma lipids could notably affect the sperm concentration, sperm progressive ratio(PR), sperm DNA fragmentation index (DFI). These results indicates that abnormal lipid metabolism in the male reproductive system may affect male fertility.

It seems that the sperm fatty acid spectrum is associated with n-3 polyunsaturated fatty acids (PUFA) in dietary. Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA) are the most common n-3 PUFA. Only plasma DHA/EPA may reflect the quantity of DHA/EPA in adults. Most research indicate that n-3 PUFA is the main polyunsaturated fatty acid in human sperm.

It is well known that diets have great influence on the gut microbiota composition. Many researches have delineated the cause and effect relationship between disturbed gut microbes and diseases, such as irritable bowel syndrome, obesity, diabetes. The disturbed gut microbiota ecosystem may also lead to the intestinal mucosal permeability increasing, which may result in endotoxemia and a series of metabolic syndrome. N-3 polyunsaturated fatty acids may play an important role in regulating metabolism and physiological functions in the body. A clinical research found that both total n-3 PUFA and DHA serum levels were significantly correlated with microbiome alpha diversity. Therefore, investigators may try to figure out the influence of n-3 PUFA supplement on gut microbiota composition and whether the gut microbiota have influence on sperm parameters. So investigators apply for your permission to collected the fecal samples from the participants, which will be a meaningful work.

In the previous work, investigators found high fat diet induced gut microbiota dysbiosis can lead to low sperm motility and sperm count, and also recognised some microbes which may lead to the low sperm motility and sperm count. It is obvious that gut microbiota can influence the sperm quality. And the supplement of n-3 PUFA is significantly correlated with microbiome alpha diversity. So investigators want to collected the fecal samples from the participants, to ascertain whether the supplementation of n-3 PUFA can promote sperm parameters by improve gut microbiota ecosystem.

The potential microbes planing to cultivate: Prevotella spp, bacteroides spp.

Inclusion Criteria:

• Clinical diagnosis of Oligoasthenoteratospermia.

Exclusion Criteria:

• Leukocytospermia, prostatitis, genital trauma, testicular torsion, urinary tract infections, cryptorchidism, varicocele, diabetes, inguinal and genital surgery.
• Y chromosome microdeletion and chromosomal karyotype abnormality.
• Extreme oligospermia.
• Hepatobiliary diseases, kidney failure.