This study investigated how hormonal induction, female presence, and production system affect sperm quality in Astyanax lacustris across three experiments. In Experiment 1, males and females were kept together in the same recirculating aquaculture system (RAS) before testing. Hormonal induction consistently boosted initial motility and prolonged sperm activity, while female presence offered only a modest benefit to non-induced males and no measurable effect when males were induced. Sperm concentration remained similar across treatments. Experiment 2 evaluated the same factors using broodstock originating from different rearing environments. When males and females came from separate RAS units, hormonal induction again sustained higher motility, and induced males paired with females showed higher sperm concentration than some non-induced groups. In the RAS–biofloc technology (BFT) pairing, hormonal induction maintained motility regardless of female presence; however, in the absence of hormonal induction, both sperm motility and concentration were modulated by the rearing system of females, with non-induced males paired with BFT females exhibiting lower reproductive performance. Overall, hormonal induction proved to be the most reliable strategy for ensuring high semen quality in A. lacustris. Nonetheless, when induction was not applied, male reproductive performance became more sensitive to female origin and rearing environment, highlighting the importance of broodstock compatibility and production system history in reproductive management protocols.

Recurrent pregnancy loss (RPL) is a clinically important condition in women undergoing assisted reproductive technologies (ART). This study evaluated embryo morphology and morphokinetic parameters using time-lapse monitoring (TLM) and assessed embryo ploidy by preimplantation genetic testing for aneuploidy (PGT-A) in women with RPL compared with unexplained infertility (UEI) controls. A total of 190 patients (100 RPL, 90 UEI) and 1169 embryos (634 RPL, 535 UEI) cultured under TLM were analyzed. Clinical characteristics, embryo morphology, morphokinetics and ploidy status were compared between groups, and logistic regression was used to identify predictors of aneuploidy. The euploidy rate was significantly lower in the RPL group than in controls (43.5% vs. 52.3%, p = 0.018). Group-wise analysis of all embryos revealed differences in selected morphokinetic parameters (t9 and tSC; p < 0.05). However, morphokinetic timing of euploid embryos did not differ between groups, suggesting that accelerated development alone was not associated with chromosomal abnormality. Embryo morphology was the strongest predictor of aneuploidy in both cohorts. Notably, direct uneven cleavage was associated with a 3.4-fold increased risk of aneuploidy specifically in the RPL group. Although embryos from RPL patients showed relatively faster developmental kinetics, morphokinetic speed alone did not predict chromosomal competence. Instead, embryo quality remained the key determinant of aneuploidy, while the association between direct cleavage and aneuploidy highlights the potential clinical value of TLM when combined with PGT-A. These findings support a complementary role for TLM in embryo assessment in RPL patients.

This study investigated the expression profile of the Toll-like receptor 2 (TLR2) gene in goats across three reproductive groups – twin-bearing (n = 12), single-bearing (n = 10) and non-pregnant (n = 8) – using quantitative real-time PCR (qRT-PCR). Descriptive statistics revealed that twin-bearing goats were significantly heavier at service and kidding, with higher litter weights compared to other groups (p < 0.05). No breed-wise differences were observed, allowing pooled analysis for gene expression. Melt curve and amplification plot analyses confirmed primer specificity and efficient amplification. TLR2 expression was significantly upregulated in twin-bearing goats (ΔCt = −2.14 ± 0.89), with a mean 4.5-fold increase (p < 0.001) compared to non-pregnant controls, suggesting enhanced immune activation. Single-bearing goats showed negligible and non-significant changes in expression (ΔCt = −0.01 ± 1.45; p = 0.984). Statistical comparisons showed a significant difference in TLR2 expression between twin- and single-bearing groups (mean difference: 3.39; p < 0.001). These results reveals a significant association of twin pregnancies with elevated expression level of TLR2 gene in resource population. While the functional implications require further investigation, this upregulation may be associated with immune adaptations to increased gestational load. Overall, this study identifies TLR2 as a candidate gene expression marker strongly correlated with twin pregnancy in goats. Further validation through longitudinal studies on larger cohorts and investigation of tissue-specific expression is necessary to assess its potential predictive value for reproductive performance in small ruminants.

This study aimed to evaluate the effects of linseed supplementation on the in vitro production of embryos subjected to vitrification. Pantaneira cows supplemented with linseed or not (control) were evaluated. The best-quality embryos produced in vitro from both groups were vitrified. Oocyte quality and blastocyst rate did not differ between the groups. However, the rates of vitrifiable embryos and re-expansion at 3 h were higher in the linseed-supplemented group. In conclusion, linseed supplementation in Pantaneira cows improved the quality of embryos produced in vitro.

Infertility aetiology has been shown to be related to reproductive outcomes in the wide reproductive age range. The aim of this study was to examine young women in vitro fertilization (IVF) cycle outcomes according to age and infertility cause. This retrospective cohort study was comprised of 305 couples with a female partner aged 17–25 years with either male or female infertility that underwent a fresh IVF cycle between 2003 and 2020. Comparison according to age groups 17–22 years (n = 117) and 23–25 years (n = 188) showed similar outcomes, except for higher rates of 3 pronuclei (PN) embryos in the younger group. However, allocation to groups by infertility aetiology - male factor (MF) (n = 241) vs. female factor (FF) (n = 64) demonstrated lower fertilization rate in the FF vs. MF group (58% vs. 63%, p = 0.049) and higher percent of 1PN and 3PN embryos (0.7% vs. 0.2% and 0.7% vs. 0.1%, p < 0.001 for both). Chemical pregnancy and live-birth rate were significantly higher in the MF vs. FF group (48.9% vs. 29.5%, p = 0.02 and 41.9% vs. 11.0%, p = 0.038). The only parameter associated with live birth rate in a logistic regression analysis was male infertility aetiology (OR = 2.17, p = 0.038). Young couples undergoing IVF cycles due to female factor infertility have poorer reproductive outcomes compared to male factor-related infertility and higher rates of 1PN and 3PN embryos.

Histone lysine-specific demethylase 4A (KDM4A) plays a critical role in the embryonic development of mammals such as mouse and goat, however its function in zebrafish (Danio rerio) embryogenesis remains poorly understood, due to the existence of two kdm4a paralogs (kdm4aa and kdm4ab) in zebrafish. The current study revealed that kdm4aa–/– embryos exhibited dramatically increased mortality during gastrulation. RT-qPCR showed that RNA-binding motif protein 46 (rbm46) was downregulated after kdm4aa knockout. CUT&Tag-qPCR revealed that kdm4aa knockout significantly decreased H3K4me3, while increasing H3K9me3 and H3K36me3 at rbm46 promoter. kdm4aa–/– embryos displayed elevated reactive oxygen species (ROS) and reduced adenosine triphosphate (ATP). And rbm46 mRNA injection alleviated ROS accumulation and increased ATP level, thereby rescuing the lethal phenotype in kdm4aa–/– embryos. Our findings demonstrate that kdm4aa knockout disturbs zebrafish embryogenesis by suppressing rbm46 mRNA expression.

Zygote wishes to inform its readers that its Editor-in-Chief has decided to retract the above article after an investigation carried out in compliance with the Committee on Publication Ethics guidelines found that the authors duplicated substantial parts of the following two articles:

1. 1. Kim H, Yamanouchi K, Nishihara M. (2006) Expression of ski in the granulosa cells of atretic follicles in the rat ovary. J. Reprod. Dev. 52, 715–721

2. 2. Kim H, Yamanouchi K, Matsuwaki T, Nishihara M. (2012) Induction of Ski protein expression upon luteinization in rat granulosa cells without a change in its mRNA expression. J. Reprod. Dev. 58, 254–259

Sloan-Kettering virus gene, a product of a cellular proto-oncogene c-Ski is a unique nuclear pro-oncoprotein and belongs to the Ski/Sno proto-oncogene family. The aim of the present study was to locate Ski protein in rat ovaries in order to find insights into the possible involvement of Ski in follicular development. First, expression of c-Ski mRNA in the ovaries of adult female rats was confirmed by RT-PCR. Then, ovaries obtained on the day of estrus were subjected to immunohistochemical analysis for Ski and proliferating cell nuclear antigen (PCNA) in combination with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). RT-PCR and in situ hybridization revealed that c-Ski mRNA was expressed in the ovaries of the adult rat on the day of estrous and localized mainly in the granulose cells. Ski was expressed in granulosa cells that were positive for TUNEL, but negative for PCNA, regardless of the shape and size of follicles. Expression of Ski in TUNEL-positive granulosa cells, but not in PCNA-positive granulosa cells, was also verified in rats having atretic follicles with double staining. These results indicate that Ski is profoundly expressed in the granulosa cells of atretic follicles, but not in growing follicles. Based on the present findings, Ski may play a role in the apoptosis of granulosa cells during follicular atresia.