农林科学最新文献

The aims of this study were to: 1) evaluate the impact of intravaginal progesterone (P4) inserts containing different amounts of P4 on pregnancy rates of predominantly Bos taurus beef cows exposed to fixed-time artificial insemination (FTAI) using estradiol and P4-based synchronization protocols, and 2) evaluate the impact of delayed luteolysis on the fertility of cows receiving P4 insert with less P4. Cows (n = 1744) were randomly assigned to 1 of 3 treatments: 1) 2.0 mg of estradiol benzoate together with an intravaginal P4-releasing insert containing 1.9 g of P4 (CIDR) on Day 0; 12.5 mg of dinoprost tromethamine on Day 7; 300-IU of equine chorionic gonadotropin together with 0.6 mg of estradiol cypionate and CIDR withdrawal on Day 9 (CIDR-PG7); 2) cows were exposed to the same treatment as CIDR-PG7, however a different intravaginal insert containing 0.5 g of P4 (DIB 0.5) was utilized (DIB-PG7); and 3) cows were exposed to the same synchronization treatment as DIB-PG7, however a dinoprost tromethamine injection was administered on Day 9 instead of Day 7 (DIB-PG9). All cows received a fixed-time artificial insemination (FTAI) 48 h after P4 inserts CIDR removal (Day 11). Circulating concentrations of P4 on Day 9 were greater (P < 0.01) in cows receiving CIDR-PG7 than in cows receiving DIB-PG7 or DIB-PG9. Dominant follicle diameter on Day 9 was greater (P < 0.01) in DIB-PG7 compared with CIDR-PG7 or DIB-PG9, but not different (P > 0.10) between CIDR-PG7 and DIB-PG9 treatments. Follicle diameter on Day 11 did not differ between CIDR-PG7 and DIB-PG7 (P > 0.10), which were greater compared with DIB-PG9 (P < 0.01). Dominant follicle growth between Days 9 and 11 was greater (P < 0.01) in cows receiving CIDR-PG7 than in cows receiving DIB-PG7 and DIB-PG9, which were not different (P = 0.18) among them. Pregnancy rates on experimental Days 41 and 131 were greater (P < 0.01) in cows receiving CIDR-PG7 (59.4 %; 55.5 %) compared with DIB-PG7 (40.1 %; 34.4 %) or DIB-PG9 (45.2 %; 41.4 %) cows. Compared with cows receiving DIB-PG7, cows receiving DIB-PG9 treatment tended (P = 0.08) to have a greater pregnancy rate on experimental Day 41 and 131 (P = 0.06). In summary, intravaginal P4 inserts with only 0.5 g of P4 resulted in decreased circulating concentrations of P4 and decreased pregnancy rates. Delaying induction of luteolysis only partially mitigated this negative outcome.

This study assessed postmortem proteolysis over 14 d in bovine Masseter (MS), Longissimus thoracis (LT), and Cutaneous trunci (CT) muscles. First, the metabolic, contractile, and connective tissue properties were characterized to establish their intrinsic differences. The MS contained the highest levels of oxidative markers and myosin heavy chain-I (MyHC-I), whereas the CT possessed the greatest glycolytic capacity, MyHC-IIx, and connective tissue proteins (P < 0.05). The LT had intermediate metabolic characteristics, a heterogeneous mixture of MyHC isoforms, and the lowest amount of connective tissue proteins (P < 0.05), confirming the muscles' intrinsic divergence. Proteolytic analysis revealed increased desmin and slow troponin-T (TT-slow) degradation, with a higher 110 kDa band intensity in the MS than in the CT (P < 0.05). In comparison, the CT exhibited greater TT-fast degradation and higher 30 kDa fragment intensity (P < 0.05). The LT demonstrated the greatest overall proteolysis, indicated by increased TT-fast and TT-slow degradation and the highest intensity of the 30 kDa band (P < 0.05). This is likely due to protease activity, as the LT and MS exhibited more calpain-1 autolysis and less calpastatin abundance than the CT (P < 0.05). However, caspase-3 activity was highest in the MS and lowest in the LT. A principal component analysis incorporating proteolytic indicators further demonstrated the distinct proteolytic profiles in the three muscles. Overall, findings suggest that the progression of postmortem proteolysis is muscle-specific and that a single proteolytic indicator does not sufficiently describe proteolysis when comparing muscles differing in contractile and metabolic properties.

The application of bovine single-chain recombinant follicle stimulating hormone (bscrFSH) for developing new superovulation (SOV) protocols with a reduced number of FSH applications was tested in lactating dairy cows with the aim of reducing animal welfare concerns and lowering labour requirements. Embryo donor cows were randomly divided into two experimental groups (n = 12 each) to undergo two different SOV protocols: a) SOV protocol using four bscrFSH applications (one dose/day, 24 h apart, four consecutive days; total: four decreasing doses), and b) SOV protocol using two bscrFSH applications (one dose/day, 48 h apart, two alternate days; total: two decreasing doses) to determine their potential effects on superovulatory response, circulating hormone levels, and in vivo embryo production. Circulating 17β-estradiol, FSH, LH, and progesterone concentrations were unaffected over time by bscrFSH treatment, irrespective of the SOV protocol used (p > 0.05). The dimension and number of ovarian structures was greatest for cows treated with four bscrFSH applications (ovulatory follicles on Day 8: 14.4 ± 1.2 vs. 12.8 ± 0.9 (p > 0.05); corpora lutea on Day 15: 10.0 ± 0.0 vs. 7.8 ± 0.2 (p < 0.05), for four and two bscrFSH applications, respectively). The number of transferable embryos and total embryos (transferable + degenerated) differed between bscrFSH treatments and was greatest for cows treated with four bscrFSH applications (transferable embryos: 6.0 ± 0.5 vs. 5.2 ± 0.2 (p < 0.05); total embryos: 8.0 ± 0.3 vs. 7.1 ± 0.2 (p < 0.05), for four and two bscrFSH applications, respectively). Moreover, the number of unfertilized oocytes differed between SOV protocols (0.1 ± 0.0 vs. 0.3 ± 0.1 (p < 0.05), for four and two bscrFSH applications, respectively). In conclusion, the treatment using two bscrFSH applications affected the number of corpora lutea, the sum of transferable embryos, and unfertilized oocytes. However, superovulation response can be successfully induced with just two applications of bscrFSH maintaining similar circulating hormone profiles and a reasonable number of in vivo produced embryos compared to cows treated using four applications of bscrFSH.

In dogs, the characterization of intraluminal uterine contents has been subjectively carried out by the operators. The aims of this study were: 1) To ultrasonographically describe and compare the echogenicity and heterogeneity of the intraluminal uterine contents in bitches using digital analysis; 2) To assess the cytology of the uterine contents; 3) To evaluate the effect of clinical, ultrasonographic, bacteriological and cytological parameters on intraluminal contents echogenicity and heterogeneity. Twenty-one intact, 3-24 kg, 1-12 years of age, female dogs with ultrasonographically detected uterine content were included. According to the gross evaluation, the contents were classified as purulent (PC; n = 8), mucous (MC; n = 4), serous (SC; n = 9). Ultrasonographic images of the contents were digitally analyzed to measure echogenicity and heterogeneity, represented as the mean gray value (MGV) and the standard deviation of the gray value (SDG), respectively. Endometrial cytology samples were collected post-ovariohysterectomy. Clinical, ultrasonographic, bacteriological and cytological parameters were compared among groups using one way ANOVA and Chi-square tests. A generalized linear model was performed to analyze their effect on MGV and SDG. Uterine diagnoses included cystic endometrial hyperplasia - pyometra, cystic endometrial hyperplasia, cystic endometrial hyperplasia - mucometra, endometritis and normal uteruses. MGV was higher in PC and MC than in SC (P < 0.01), did not differ between PC and MC (P > 0.1). SDG was higher in PC than in SC (P < 0.01) and MC (P < 0.05). Digital analysis distinguished among purulent, mucous and serous fluids. Cytology revealed higher inflammation-related parameters in PC than in MC and SC. Cytological parameters, such as cellularity and bacterial presence, were associated with echogenicity and heterogeneity of uterine contents.

Prospermatogonia (ProSGs), the progenitors of spermatogonial stem cells in neonatal testes, undergo critical migration to the testicular microenvironment-a fundamental process for testicular development and subsequent spermatogenic capacity. The SDF-1/CXCR4 chemokine axis serves as an essential molecular guidance mechanism, directing ProSGs toward the basal membrane of seminiferous tubules. Nevertheless, the precise molecular mechanisms governing this axis remain incompletely understood. Utilizing a porcine in vitro model system, this investigation elucidated the molecular mechanisms underlying the SDF-1/CXCR4 axis in ProSGs fate determination. Through integrated molecular and transcriptomic analyses, we investigated the consequences of CXCR4 inhibition on ProSG cellular dynamics. Our findings demonstrated that the SDF-1/CXCR4 axis exerts regulatory control over ProSGs differentiation via the PI3K-AKT-AP-1 signaling cascade. This regulation significantly influences the transcriptional landscape of ProSGs, particularly modulating the expression of PLZF, a crucial suppressor of spermatogonial differentiation, and DMRT1, an essential mediator of germ cell differentiation. These findings elucidate the molecular mechanisms orchestrating ProSGs homing and emphasize the significance of maintaining male reproductive competence. Furthermore, this research could enhance our understanding of ProSGs biology and its relationship to boar fertility, while potentially facilitating the development of innovative reproductive technologies and sustainable livestock management strategies.

To improve the efficiency of in-vitro-produced (IVP) porcine embryos, we focused on the events that usually occur during in-vivo embryonic transit from the oviduct to the uterus. Extracellular vesicles (EVs) are released by different mammalian cells and are imperative for intercellular communication and reflect the cell's physiological state. Based on these characteristics, EVs were isolated from oviductal and uterine fluid to imitate the in vivo environment and improve the efficiency of IVP embryos. Parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) embryos were divided into four groups based on treatment methods designed to mimic the in vivo migration pathways of porcine embryos. (Group 1) control group; (Group 2) a group treated with EVs from oviduct-derived fluid for 0-3 days (Ov-EVs), (Group 3) a group treated with EVs from uterus-derived fluid for 3-7 days (Ut-EVs); (Group 4) and a group treated with both (Ov, Ut-EVs). The EVs were characterized using various techniques, and their uptake into oocytes was confirmed using PKH67. The results demonstrated an increase in mitochondrial activity of PA embryos in Groups 2 and 4 at the 4-cell stage. Furthermore, compared with Group 1, the total number of cells in PA blastocysts was higher in the Group 2, 3 and 4, and the number of apoptotic cells was significantly lower. In SCNT experiments, the blastocyst development rate was increased in the EV-treated groups compared to the Group 1. Therefore, Ov-EVs and Ut-EVs can improve the embryonic development rate of IVP embryos, increase cell numbers and mitochondrial activity, and reduce apoptosis, thereby improving embryonic quality. Thus, integrating EV-based support into IVP embryos may advance swine reproductive technology and improve its practical applications.

Wanxi white goose is an important male parent in crossbreeding of Chinese geese, but its short reproductive cycle restricts its application in Northeast China. Therefore, understanding the potential mechanism of breeding period regulation in Wanxi white goose will help to provide more options for crossbreeding. In this study, the reproductive period was divided into prophase (T1), metaphase (T2) and anaphase (T3) according to the laying rhythm of geese. Based on this, testicular tissues were stained and further analyzed by DIA proteomics. A total of 69577 Unique spectra, 70325 Unique peptides and 6275 proteins were identified. Among them, various differentially expressed proteins were enriched to metabolism-related pathways. Furthermore, trend analysis was performed based on the differentially expressed proteins in which four significant differences of protein expression trends were obtained. Additionally, the PPI protein network analysis helped us to further locate the core genes, such as CDC42, RAC2, IFT81, CSTF2, MRPS35 and BIRC5. Finally, we detected the protein expression of SOX9, RAC1, RhoA and Lyn, which was significantly correlated with the sequencing results. Generally, in this study, several genes and proteins involved in developmental biology and metabolic pathways were involved in the reproductive regulation of Wanxi white goose, which will lay a foundation for us to further study the reproductive regulation of Wanxi white goose.

Clostridium spp. poses a significant problem in meat sausages, particularly semi-dry fermented meat products, during storage. The present study evaluated the anti-clostridial effects of nisin (0.05-0.1 %) and mixed lactic acid bacteria (LAB) cultures (Lactiplantibacillus plantarum, Lactococcus lactis subsp. lactis) on Clostridium sporogenes endospores in vacuum-packaged, nitrite-reduced heat-treated Turkish-type dry fermented sausage (sucuk). Also, it examined the effect on the products' technological properties and microbiological safety over a 45-day storage period at 4 °C. The reduction in total spore-forming bacteria (TSFB) and anti-clostridial efficacy were determined using 0.05 % nisin in nitrite-reduced sucuk and 0.1 % nisin in nitrite-free sucuk, indicating a significant interaction between treatment and storage day (P < 0.001). The combination of 150 ppm sodium nitrite (NaNO₂) and 0.05 % nisin in nitrite-reduced sucuk resulted in the lowest thiobarbituric acid reactive substances (TBARS) values (P < 0.001). Furthermore, using 150 ppm NaNO₂ and 0.1 % nisin in nitrite-free sucuk more effectively preserved the initial color values compared to the control group (P < 0.001). While reducing or removing NaNO₂ in heat-treated sucuk did not compromise safety regarding C. sporogenes endospores under the conditions tested, the antimicrobial role of NaNO₂ should not be disregarded. Therefore, 0.05 % nisin in nitrite-reduced sucuk is recommended to effectively inhibit C. sporogenes endospores and improve the oxidative stability of heat-treated Turkish-type dry fermented sucuk.

The main objectives of the present study were to determine the effects of presynchronizing with a 1.0 g intravaginal progesterone device (IVPD) and prostaglandin F2α and to assess the effects of re-utilization of IVPD in a 2x2 factorial design, on the ovulatory response to first GnRH, ovarian status at different protocol stages, estrus expression and fertility in beef heifers submitted to a 5d-CO-Synch + Progesterone (P4) protocol. Beef heifers (n = 564) were assigned to 1 of 2 treatments at D-15: Pres5 (n = 283), where heifers received a (IVPD) for 5 days and administration of prostaglandin F2α (25 mg of dinoprost) at D-10; and Control (n = 281), where heifers received no treatment. At D-8, all heifers received 100 μg of GnRH (gonadorelin acetate) and were assigned to 1 of 2 IVPD-use treatments: new-IVPD (n = 279), where animals received a new IVPD for 5 days, and once-used IVPD (n = 285), where heifers received a once-used IVPD for 5 days (used previously for 5 days). On D-3, IVPD was removed and 50 mg of prostaglandin F2α was administered. All heifers were timed artificially inseminated (AI; D0) 62 h after IVPD removal concomitant with an administration of 100 μg of GnRH. Estrus detection patches were placed on heifers at D-3 and evaluated at the time of AI. In a subset of heifers (n = 278), transrectal ultrasonography of the ovaries was carried out at D-8 and D-3 to assess presence and diameter of CL and largest follicle diameter (LFD). A blood sample was collected on D-3 to determine serum P4 concentration. Heifers with a once-used IVPD had a greater (P = 0.01) pregnancy per AI (P/AI) than heifers treated with a new-IVPD [62.8 % (179/285) vs 51.2 % (143/279)]. There was a lower percentage of animals (P = 0.002) having a corpus luteum (CL) on D-8 in Pres5 group compared to Control [16.4 % (22/134) vs 69.4 % (100/144)]. Similarly, a greater percentage of Pres5 heifers had a dominant follicle on D-8 (P < 0.0001) than Control heifers [97.7 % (131/134) vs 75.7 % (109/144)]. At D-3, Pres5 heifers had a greater ovulatory response to D-8 GnRH (P < 0.0001) compared to Control animals [82.8 % (111/134) vs 49.3 % (71/144)]. In addition, Pres5 heifers had a greater estrus expression behavior [87.6 % (248/283) vs 72.9 % (205/281); P < 0.0001] and tended to have (P = 0.10) a greater P/AI [61.8 % (175/283) vs 52.3 % (147/281)] than Control heifers. In conclusion, the tendency for a greater fertility observed in Pres5 heifers (∼10 %) justifies the extra animal handling required for presynchronization. A once-used IVPD represents a viable strategy to enhance P/AI and reduce the cost in beef heifers submitted to timed AI.

The uterine artery resistivity index (RI) obtained by Doppler ultrasonography has become a common method in evaluating uterine blood flow during pregnancy for assessing canine fetal and placental conditions. During pregnancy, embryonic vesicle resorptions can be observed by ultrasound and have been found to increase with the aging of the dam. The RI is higher during induced abortion in bitches, while its relationship with early embryo resorptions is not yet clearly defined. The aim of this study was to evaluate whether the uterine artery's haemodynamics at pregnancy diagnosis are related to embryo resorption rates and other pregnancy and dam parameters. The ultrasound examinations were performed 25 ± 4 days post-ovulation (between days 21 and 29). During the examinations, the animals were in lateral recumbency, and both uterine horns were scanned to determine the number and viability of embryos and resorption sites. The left uterine artery was visualized, and the RI was determined. The breed, weight, reproductive anamnesis, and age of the animals were recorded. Forty-four bitches were included, weighing 2.8-39.2 kg, for 50 pregnancy diagnoses performed at ages ranging from 18 to 88 months. Bitches were allocated to different size groups according to their body weight and breed: Medium (M, 10-40.0 kg), Small (S, 5-9.9 kg), and Toy (XS, <5 kg). A linear regression was used to model the RI as the outcome, with size group and age of the dam (above or below the median value), litter size (sum of viable embryos and resorptions), gestational age (days post-ovulation), parity (multiparous vs. primiparous), cystic endometrial hyperplasia (present or not), and either the percentage of resorptions (on litter size) or simply their presence as predictors. The overall model was statistically significant (P = 0.029), with an R² index of 0.296. A significant relationship with the response was found for gestational age (P = 0.012) and percentage of resorptions (P = 0.045). No significant relationships were found for the other parameters. As reported in the literature, as gestational age increased, RI decreased. Embryo resorptions were observed in 17/50 (34.0 %) pregnancies. As the percentage of resorption sites within the pregnancy increased, the RI also increased. Conversely, the simple presence or absence of resorption sites had no statistically significant effect on the RI. This study describes, for the first time, a significant impact of embryonic resorptions on uterine artery RI at pregnancy diagnosis. Whether these changes are a cause or effect of the abnormal pregnancy remains to be elucidated.