Animal Reproduction最新文献

Intratesticular injection of chemical agents in dogs has been investigated for nearly half a century as promising methods for nonsurgical sterilization. This study was conducted to determine the effects of formalin and calcium chloride injection in mediastinum testis on semen quality, testicular width, testosterone level and histopathological changes in dogs, and to evaluate the usability and success of the intra mediastinum testis injection technique in chemical castration. Eighteen adult male dogs were divided into 3 groups including a control (0.5 ml 0.9% saline solution), formalin (5%) and CaCl₂ (50%) into the mediastinum. Testicular diameter, spermatological characteristics and testosterone concentrations were determined on days 0, 22 and 44 following applications. The dogs were castrated on 45 day and the testicles were sent to the laboratory for histopathological examinations. Formalin and CaCl₂ administered groups showed apparent enlargement and firmness of the testis with symptoms of discomfort and pain. One dog in the formalin group and two dogs in the CaCl₂ group developed scrotal inflammation within three days, which progressed to scrotal ulceration and fistula formation. On day 44 after treatment, it observed that sperm motility and sperm concentration in the formalin and CaCl₂ groups were decreased compare to control group while dead and abnormal sperm rates were increased (P<0.05). The testosterone concentration significantly increased in CaCl₂ compare to control and formalin groups on day 44 (P<0.05). In histopathological evaluations, moderate degenerative changes were detected in the testicular tissue of the formalin group. The findings of this study showed that CaCl₂ and formalin injections into the mediastinum testis under ultrasonography guidance are easily to perform and could be alternative to both the intratesticular injection and the surgical technique.

Pregnancy induces critical physiological adaptations to support embryonic development and fetal survival. This study compared endometrial and placental phenotypic and histomorphometric characteristics of Piau and Commercial sows at two gestational ages (25 and 35 days). Twelve sows (six Piau and six Commercial) were evaluated in a randomized design, with samples collected from three regions of the right uterine horn of each animal. Histomorphometric analyses were performed using microscopy and ImageJ software. Statistical analyses employed linear mixed-effects models, with Shapiro-Wilk and Levene's tests applied to assess normality and homogeneity of variances, respectively. At 25 days of gestation, Commercial sows showed greater uterine and ovarian weights, a higher number of corpora lutea, and longer uterine horn horns, reflecting genetic selection for reproductive efficiency. Conversely, Piau sows exhibited more advanced embryonic development at this stage, with fetuses of greater size. At 35 days, the phenotypic superiority of Commercial sows persisted, while Piau fetuses maintained greater weight and length, indicating distinct temporal growth dynamics. Histomorphometric analyses at 25 days revealed that Commercial sows had increased placental connective tissue deposition and thicker endometrial epithelium, whereas Piau sows presented larger placental vascular area, as well as enhanced endometrial vascularization and glandular density across all uterine regions. At 35 days, no significant differences were observed in placental vascular area and endometrial vascularization; however, subtle trends in connective tissue development suggested ongoing placental differentiation. These findings highlight distinct reproductive strategies between Piau and Commercial sows, with potential implications for embryonic development and gestational success. Altogether, the results confirm that genetic background influences uterine and placental morphology during early gestation.

Since temperature plays an important role in feed consumption, chemical reactions and metabolism, it was hypothesized that it is below ideal it could interfere in the masculinization of tilapia in biofloc system (BFT) and the ideal methyltestosterone (MT) concentration in the feed. The masculinization rates of Nile tilapia in a zero-water exchange BFT (and without clarification) at 25°C and 28 °C combined with concentrations of MT in the feed (0 (control), 10, 20, 30 and 40 mg ∙ Kg^-1 of feed) were evaluated using 3 replicates per treatment (30 tanks of 50 liters, 2 larvae ∙ L^-1). Larvae were fed five times a day for 28 days. The water quality and growth performance did not diverge between MT concentrations (p > 0.05). Larvae grew 2.7 times higher in 28°C than 25°C. The control treatments did not differ from each other for male proportion (mean = 66,75%) but differed from all hormonal treatments. These treatments presented masculinization rates above 98.7% and 96.9%, at temperatures of 25°C and 28°C, respectively, and did not differ from each other at the same MT concentrations. Therefore, it is feasible to use an even lower concentration (10 mg of MT ⋅ Kg^-1 of feed) in a zero-water exchange BFT, regardless of these temperatures. At the lower temperature, the input of MT in the system was smaller due to smaller feed intake, however the fingerlings would take longer to reach commercial body weight. Furthermore, after 2 hours of the last hormone feeding, MT residues were not detected in any biofloc/water mixture samples.

The presence of follicles and the corpus luteum (CL) in the ovarian surface plays a key role in determining the morphological and molecular fate of the female reproductive tract. However, the specific response of the isthmus epithelium to these ovarian structures remains poorly understood. This study hypothesizes that distinct ovarian structures differentially affect both the cellular aggregate-forming capacity of oviductal isthmus cells and the expression of ESR1, ESR2, and PGR genes. Reproductive tracts were categorized into three groups: ovaries with ≤5 mm follicles (small follicles group; SF); ovaries with follicles between 8-10 mm (large follicles group; LF); and ovaries containing active corpus luteum (CL Group). Isthmus cells from the three groups were cultivated to form cellular aggregates (oviductal explants) during 24 h. Moreover, the expression levels of ESR1, ESR2, and PGR genes were analyzed in the isthmus cells of the experimental groups. The isthmus cells of LF group showed an increased number of cellular aggregates than SF and CL group. Additionally, the SF group presented more aggregates than the CL group. Gene expression analysis revealed that ESR1 expression was higher in the SF group than in the LF group. Moreover, PGR expression was greater in the CL than in the SF group, as well as in the LF than in the SF group. In conclusion, ovarian structures impact the cellular aggregate formation capacity and the gene expression of ovarian steroid receptors in isthmus cells.

The aim of this study was to evaluate the probability of pregnancy in heifers weaned at different ages and bred at 13 to 15 months old. A total of 121 Braford heifers were used, weaned as calves at 77 days (early) or 147 days (conventional) of age. To develop the statistical models of reproductive performance, factors related to the development of the heifers were analyzed. The analysis included a diagnosis of multicollinearity using the Pearson correlation matrix, adjusting the model by means of the Hosmer and Lemeshow test. The response variable, rate of pregnancy, was analysed using the LOGISTIC procedure. Beginning with a weight of 271 kg and an age of 402 days at the start of the breeding season, the pregnancy rates increased by 18.4% and 29.0%, respectively for every 15 kg increase in body weight and 10-day increase in age. However, a reduction of 15 kg in body weight and of 10 days in age reduced the pregnancy rates in the heifers by 15.5% and 22.5%. An increase or reduction of 0.100 kg in the average daily gain between early weaning and conventional weaning represented an increase of 44.6% and a reduction of 30.9% in the chances of pregnancy. Early-weaned heifers require correct nutritional management to allow satisfactory postweaning weight gains so as not to compromise their reproductive performance.

Luteinizing hormone (LH) plays a crucial role in follicle development, ovulation induction, and the regulation of key reproductive events. However, the efficacy of LH within the follicular microenvironment largely depends on the capacity of follicular cells to express its receptor. This study aims to investigate whether granulosa cells (GCs) can acquire LHR through extracellular vesicles (sEVs) present in follicular fluid (FF) from follicles of varying sizes. In the first experiment, GCs and sEVs were collected from the FF of small (3-5 mm), medium (5.1-7 mm), and large (7.1-9 mm) ovarian follicles from Bos taurus indicus cows. In the second experiment, GCs and sEVs were collected from the FF of small (3-6 mm) and large (8-14 mm) follicles from Bos taurus taurus cows. Initially, we assessed the ability of sEVs to carry LHR mRNA by comparing its expression profiles in sEVs derived from different size follicles. Our findings revealed that as follicular development progresses, LHR levels in FF sEVs decrease, while in corresponding GCs, from which the sEVs primarily originate, show increased LHR expression. To further investigate whether GCs represent an additional source of FF sEVs carrying LHR mRNA, GC cultures were established and sEVs secreted into the culture medium (ME-sEVs) were analyzed for LHR mRNA levels. A similar pattern was observed in ME-sEVs derived from GCs of small versus large follicles, with decreased LHR mRNA levels in sEVs secreted by GCs from large follicles compared to small follicles. This suggests that LHR is likely packaged into sEVs in small follicles stage, and shuttled into follicular cells during follicular growth, preparing them for the ovulatory stimulus. Our study uncovers a possible mechanism of LHR acquisition by GCs, which involves EVs and can possibly be involved in follicle quality and ability to respond to LH stimulus.

The aim of this study was to evaluate the effects of in vivo oocyte maturation using seminal plasma alone or in combination with an additional period of in vitro maturation (IVM) on the developmental competence of alpaca oocytes. The experiment was conducted in Lima, Peru, with twelve adult female alpacas. Follicular ablation of the dominant follicle was performed to initiate a new follicular wave. After 36 hours, a superstimulation protocol with 750 IU of eCG was administered intramuscularly (IM). Four days later, 2 mL of seminal plasma was administered IM to promote in vivo oocyte maturation. Cumulus-oocyte complexes (COCs) were retrieved via ovum pick-up 20 hours post-treatment, morphologically evaluated, and allocated into three groups: (T1) no additional IVM, (T2) 12 hours of additional IVM, and (T3) 18 hours of additional IVM. Oocyte developmental competence was assessed using a 26 µM brilliant cresyl blue (BCB) staining protocol for 90 minutes. COCs were classified as BCB positive (blue ooplasm) or BCB negative (unstained ooplasm) and subsequently denuded and fixed for nuclear maturation assessment via orcein staining. No significant differences (p=0.14) were observed in the percentage of expanded COCs across groups (71.4%, 81.8%, and 54.6% for T1, T2, and T3, respectively). The proportion of COCs reaching the metaphase II (MII) stage was higher (p<0.05) in T3 (54.6%), while the developmental competence rate was greatest (p<0.05) in T2 (100%). However, no differences (p=0.21) were detected in the proportion of BCB positive MII stage COCs across groups. In conclusion, alpaca oocytes matured in vivo with seminal plasma require 12 to 18 hours of IVM to achieve optimal nuclear maturation and developmental competence.

Serum calcium fluctuations are common during the peripartum period of dairy cattle and several studies have attempted to demonstrate the impact of decreased blood calcium (Ca) on subclinical endometritis; however, the highly dynamic and complex nature of the peripartum period in dairy cows may impair the establishment of the cause-and-effect relationship. The objective of this review is to compile information regarding hypocalcemia and subclinical endometritis and their relationship, as well as the available in vivo and in vitro study models that artificially induce subclinical states of hypocalcemia and endometritis in cows that are not in peripartum period. Regarding hypocalcemia, several studies have demonstrated the effectiveness and safety of protocols using Ca chelators such as ethylenediaminetetraacetic acid (EDTA) or ethylene glycol tetraacetic acid (EGTA) in vivo. The induced transitory hypocalcemia impaired feed intake, rumination and neutrophilic phagocytic and oxidative burst response. However, the effects on uterine environment remain poorly explored. Although these experimental models allow the understanding of the effects of hypocalcemia alone, without the peripartum metabolic and hormonal variations, the effects are likely underestimated because dairy cows may experience hypocalcemia for much longer periods. For studying bovine endometritis, the main experimental in vivo model is the intrauterine infusion of pathogenic bacteria or their components (lipopolysaccharide - LPS), which induce endometrial inflammation, even causing long-term negative effects. Several in vitro and ex vivo models have also been developed, which are mainly indicated to investigate the mechanisms underlying endometrial inflammation in cattle because there is no interaction with other tissues, organs and systems, as would occur in vivo. In conclusion, current models still face limitations and, therefore, future efforts to the development and refinement of in vivo and in vitro experimental models are necessary.

The aim of this study was to evaluate the effects of supplementing the cryodiluent medium with sulfated polysaccharides (SP) extracted from marine algae (Ascophyllum nodosum or Solieria filiformis) and fish skin (Colossoma macropomum, Prochilodus brevis, or Oreochromis niloticus) on the cryopreservation of tambaqui semen. Twenty male tambaqui were used for semen collection and cryopreservation. For the fertilization assay, three males and five females were used. In Experiment 1, different concentrations of SP (0.0, 0.1, 0.25, 0.5, and 0.75 mg/mL) extracted from fish skin or marine algae were added to the freezing medium for C. macropomum semen. In Experiment 2, the results of sperm velocity analyses were used to select one concentration of each sulfated polysaccharide for use in fertilization trials. Among the treatments, A. nodosum at 0.75 mg/mL and C. macropomum at 0.50 mg/mL stood out, significantly improving sperm parameters such as motility, VCL, VSL, VAP, and LIN compared to the control group. S. filiformis, P. brevis, and O. niloticus also showed good results, with performance varying by concentration. Membrane integrity was higher in the algae-derived extract groups. Sperm morphology and DNA integrity did not differ significantly among groups. Fertilization rates remained high across all treatments (84.67% to 88.67%), with no statistically significant differences, indicating that the tested extracts did not compromise fertility. It was concluded that supplementation with SP from A. nodosum at 0.75 mg/mL and C. macropomum at 0.50 mg/mL, although all treatments showed similar fertility rates, is recommended as an additive to the semen dilution medium for tambaqui during freezing, as it improved important sperm parameters such as motility and VCL.

The genes identification involved in male reproduction and the evaluation of its functions improve the comprehension about spermatogenesis molecular bases, fertilization, embryos early cleavage, spermatic quality and male infertility. The present study aimed to verify the Protamine1 (PRM1), Protamine2 (PRM2) and Cation Channel Sperm Associated 1 (Catsper1) genes expression into the equine sperm and their relations with the stallions' spermatic quality and fertility. Semen collections were performed in eighteen stallions, which were divided in two groups, based on fertility rates: fertile (with pregnancy rate per cycle ≥ 70%) and subfertile (with pregnancy rate per cycle ≤ 40%). The semen analysis was performed by Computer Assisted Sperm Analysis AndroVision®. The mRNA was extracted from the spermatozoa and the PRM1, PRM2 and Catsper1 gene expression verification in the spermatic cell was conducted by the qPCR technique. The results present a higher expression of PRM1 and Catsper1 in the fertile stallions' group than subfertile group; there was no correlation of PRM1 and PRM2 expression with spermatic quality parameters; there was correlation of the Catsper1 expression with morphology and motility parameters. Negative correlation was found between the PRM1/PRM2 ratio, fertility and motility parameters. The present research demonstrates that the PRM1 and Catsper1 genes are related to stallions' fertility and spermatic quality, and they may work as biomarkers.