The quality of the study design and data reporting in human trials dealing with the inter-individual variability in response to the consumption of plant bioactives is, in general, low. There is a lack of recommendations supporting the scientific community on this topic. This study aimed at developing a quality index to assist the assessment of the reporting quality of intervention trials addressing the inter-individual variability in response to plant bioactive consumption. Recommendations for better designing and reporting studies were discussed.

Diabetes mellitus (DM) causes male infertility through the suppression of spermatogenesis and testosterone biosynthesis. The impact of DM on male reproduction has mainly been investigated in adulthood, therefore we aimed to study the developmental effects of DM, induced in early life, on testicular cell population and fertility. Neonatal (NDM) and prepubertal DM (PDM) were induced in immature rats by streptozotocin administration on day 1 or day 10, respectively. Germ (GCs) and somatic cells (Sertoli—SCs and Leydig cells—LCs) were counted in pubertal (25 day) and post-pubertal (45 day) rats in tandem with the measurement of serum testosterone levels and the protein expression of androgen receptor. Glucose levels were higher in PDM than in NDM. Incomplete spermatogenesis and reduced GC number were found in PDM but not in NDM. LC number, testosterone, and luteinizing hormone (LH) levels were differently altered by both types of DM with a pronounced negative impact of PDM. Protein expression of androgen receptor in SCs was altered only in PDM. Reduced sperm concentration and motility was found in both groups. Thus, our results provide new insights into different mechanisms of action of PDM and NDM on developing germ cells that involved disturbances in androgen production by Leydig cells and androgen action in Sertoli cells.

The aim of this study was to evaluate the effect of ascorbic acid (Vitamin C) and 2-mercaptoethanol (ME) added to buffalo semen samples after thawing for 1 h and 2 h incubation. Ejaculates (n = 20) from eight Bulgarian Murrah buffaloes were frozen in pellets and straws at a final sperm concentration of 80 × 10⁶ mL. We investigated the effect of supplementations on the motility, morphology of spermatozoa at 1 h and 2 h after thawing, sperm plasma membrane status and mitochondrial trans-membrane potential. The comparative CASA analysis of the motility and velocity parameters of spermatozoa showed significant differences in the progressive motility and in the VCL values in favour of control vs. samples with additives (p < 0.05). The molecular changes in PM phospholipid asymmetry were higher after thawing (p < 0.05). The semen treated with Vit C showed significant (p < 0.05) lower number of apoptotic spermatozoa (6CF+/Ann V Cy3+) in comparison with samples incubated with ME. The numbers of dead spermatozoa (6CF-/Ann V Cy3+) in samples with ME were significantly higher than other groups. The percentage of spermatozoa with well preserved and functioning mitochondria in control semen was higher (p < 0.05) than that in the experimental group with ME. The results obtained revealed that addition of Vit C (5 µmol/L) and ME (50 µmol/L) has no positive effect on post-thaw semen quality of buffalo sperm, because of the impaired integrity of PM and mitochondrial trans-membrane potential.

Artificial insemination (AI) is a key reproductive biotechnology for genetic improvement in sheep. However, its efficiency remains lower and more variable than in most other livestock species. This review critically synthesizes the historical foundations of sheep AI, including methodological principles established by the Soviet school, and evaluates how these concepts have been further developed and adapted to contemporary reproductive biology. Particular emphasis is placed on estrous synchronization protocols, semen processing and cryopreservation, and insemination techniques. We highlight how anatomical constraints of the ovine cervix, seasonal reproductive physiology, and species-specific characteristics of ram sperm collectively limit fertility outcomes, especially when frozen–thawed semen is used. Comparative analysis of cervical, transcervical, and laparoscopic insemination methods indicates that laparoscopic AI remains the most reliable approach, although recent advances in catheter design and semen handling have improved the feasibility of less invasive techniques. This review further discusses emerging approaches, including sperm sex-sorting, alternative recovery methods, and early-stage spermatogonial stem cell–based technologies, emphasizing both their potential applications and current limitations. Overall, the available evidence suggests that future progress in sheep AI will depend on the integrated optimization of hormonal synchronization, semen preservation, and insemination strategies, rather than on isolated technical innovations.