Effect of Antioxidant Probiotic Administration on Seminal Quality and Reproductive Outcomes.

This is a prospective randomized, unicentric, intervention study aimed at evaluating the effect of the combination of two probiotics on seminal quality and subsequent reproductive outcomes of infertile patients. As it is a food supplement, we will be subject to the Biomedicine Regulation and not to the Clinical Trials Regulation, as already classified by the Spanish Drug Agency. The study will be conducted on infertile patients at the IVIRMA Valencia clinic for two years to complete planned interventions and data collection and analysis. The reference population includes infertile patients coming to the clinic for IVF/ICSI assisted reproduction treatment with own or donated oocytes.

Patients will come to the clinic to undergo the treatment. If their characteristics are in accord with the inclusion criteria, the study will be presented and explained to them and their partners so they can evaluate their participation in it. If they wish to participate, they will sign an informed consent form, and they will be randomized using a computer-generated randomisation list into the control group (who will receive placebo) or the treatment group (who will receive the probiotic compound).

The success rate in patients with these characteristics, confirmed by the evaluation of historical information from the clinic's own database, is approximately 35% of the cycles using own oocytes, which can be used as a valid approximation. In a unilateral contrast test, assuming a risk of an alpha error of 0.05 and a beta (statistical power) of 80%, to demonstrate a difference of 15% thanks to the intervention, we need a number of 134 cases per arm and, assuming losses of 5% during the follow-up, this number would be rounded to 140 cases per study group, which makes a total of 280 couples to be included in the study.

The trial is double-blind: the patient, the investigator and all site personnel (with the exception of the trial nurse/coordinator and/or pharmacy assistant) will remain blinded throughout the course of the trial as to which treatment each subject received, including the assessing physician, the embryologist and other auxiliary members of the team.

The male assigned to the experimental group will start taking a 50% combination of the two probiotics (Lactobacillus rhamnosus CECT8361 and Bifidobacterium longum CECT7347) at a dose of 109 CFU/day on the same day of the first visit. The probiotics will be supplied by the company ADM Biopolis S.L. (Valencia, Spain). The carrier of lyophilized probiotics is maltodextrin and the mixture is encapsulated in hypromellose capsules. The patient will take one capsule daily corresponding to the administration of 109 cfu/day. The patient should take these probiotics for at least 21 days before undergoing an assisted reproduction cycle. Patients receiving the placebo will be following the same instructions. For both groups of patients, a seminal sample will be collected on their first visit to evaluate the baseline quality of the semen, as well as a microbiome analysis will be carried out using 16S rRNA sequencing (by ADM Biopolis) to determine the status of the semen at the starting point of the study. After 21 days, the patients will be appointed to deposit a second semen sample in order to perform the IVF/ICSI cycle. This sample will also be analysed, both for semen parameters and microbiome. Values obtained from both of the samples collected will be compared to observe the effect of the administration of the probiotic on the quality of sperm and its microbial population.