农林科学最新文献

During fermentation, meat is pre-treated and cured to cultivate a diverse microflora, resulting in fermented meat products with distinctive flavors. Coagulase-negative staphylococcus holds a crucial role in all fermented meat products, contributing to the breakdown of proteins, carbohydrates, and fats, and the creation of flavor compounds. Fermentation technology has important research value and significance in fermented meat products. The optimization and improvement of flavor by CNS can be achieved by regulating the fermentation environment, initial microflora and processing conditions. The review explores the ways in which coagulase-negative staphylococci contribute to the flavors in fermented meat products. The mechanism of flavor substance formation and means of regulation in coagulase-negative staphylococci were also investigated. The review concludes by summarizing future development trends and drawing conclusions.

Accumulation of ketone bodies in the blood or tissues can trigger ketosis, exerting detrimental effects on bovine oocytes maturation. Exposure to its primary component, β-hydroxybutyric acid (βHB), disrupts mitochondrial function, culminating in the excessive buildup of reactive oxygen species (ROS) and subsequent initiation of apoptosis in oocytes. These ultimately result in poor oocyte quality. Melatonin, recognized for its endogenous antioxidant properties, is capable of mitigating ROS levels and enhancing the expression of antioxidant enzymes. In this study, we explored the protective effects of melatonin on the damages induced by βHB. Melatonin was added at a concentration of 10^-9 M to the culture medium on bovine oocytes. Parameters including first polar body extrusion rate, mitochondrial membrane potential, ROS, cell apoptosis were assessed. Results showed that melatonin could restore bovine oocyte maturation rate, enhance mitochondrial function, reduce cell apoptosis rate, and mitigate oxidative stress levels. Notably, Nrf2 signaling pathway inhibitor ML385 significantly attenuated the protective effects of melatonin on oxidative stress induced by βHB exposure. In summary, our study demonstrates that melatonin can protect oocytes from oxidative stress induced by βHB exposure, with indications that this protective mechanism may be mediated through the Nrf2 pathway.

Epigallocatechin gallate (EGCG), a natural antioxidant, plays a vital role in modulating sperm function, yet its protective impact on boar spermatozoa during liquid preservation at 4 °C remains elusive. This study aimed to investigate the beneficial effects of EGCG on boar semen preservation, and elucidate the potential mechanism. Multiple parameters including sperm quality, anti-oxidative status, protein phosphorylation levels, membrane receptor and cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signaling pathways were analyzed using computer-assisted semen analysis system, Western blot and molecular docking techniques. Results revealed that supplementation with EGCG, particularly with 10 μg/mL, significantly increased sperm motility, acrosome integrity, mitochondrial membrane potential and intracellular ATP content. Moreover, EGCG enhanced the antioxidant defenses of sperm through eliminating excessive reactive oxygen species. Intriguingly, the antioxidant property of EGCG partly prevented protein dephosphorylation, thereby indirectly enhancing protein phosphorylation. Additionally, the dopamine receptor (DRD2) was detected in boar spermatozoa and inhibition of DRD2 greatly prevented EGCG-caused enhancement of protein phosphorylation levels and sperm motility, suggesting the role of DRD2 in regulation of the beneficial effects of EGCG. Molecular docking results indicated that EGCG has favorable binding interactions with the active sites of DRD2, involving crucial hydrogen bonding and hydrophobic interactions, further suggesting that EGCG might directly interact with DRD2, mediate protein phosphorylation via activating the DRD2/cAMP/PKA pathway and thus boost sperm motility. The present study is the first to explore the interacting cell-surface receptor of EGCG on boar sperm and provides comprehensive insights into the protective mechanism of EGCG during hypothermic liquid storage.

This research aimed to explore the changes in two sampling locations (internal and external) of the Longissimus thoracis et lumborum (LTL) beef muscle proteomes subjected to ultraviolet light before dry-aging. It further compared the biological processes and associated proteins at interplay at the external locations of UV pre-treated and control dry-aged samples. Before dry-aging, proteins related to external stimuli were differentially abundant between both locations possibly due to the early post-mortem energy metabolism attempting to compensate for energy deficiencies and stress derived from slaughter and processing. The biochemical status of muscle during chilling and hanging of the carcasses and the impact of the UV pre-treatment may have also influenced the abundance of these proteins before dry-aging. Proteins associated to muscle structure, energy and fatty acids metabolism were differentially abundant between locations after 21 days of dry-aging. These dynamic changes in the meat proteome and related biological processes suggested that both evolved differently between the two sampling locations during dry-aging, and these may underlie the development of dry-aged beef properties. The proteome of the external locations sampled from UV pre-treated beef loins was compared to control counterparts during dry-aging. The results show that aging time appeared to outweigh the effect of UV since the differentially abundant proteins between both groups decreased as dry-aging progressed. These proteins were associated with mRNA stabilization, the matrisome, energy pathways and heat shock proteins (HSPs). Further research is warranted to better understand the role of these proteins in the production of dry-aged beef and their relation to the UV pre-treatment.

This study aimed to evaluate the impact of cholesterol supplementation at various concentrations in cryopreserved Pantaneiro bovine semen on in vitro embryo production (IVEP). Grade I and II cumulus-oocyte complexes (COCs) were collected from ovaries retrieved from a commercial slaughterhouse and matured in vitro for 24 h. The matured COCs were divided into four groups based on the concentration of cholesterol -loaded cyclodextrin (CLC) during semen cryopreservation from a Pantaneiro breed bull: Control (C) - 0 mg/mL CLC, T1 - 0.5 CLC, T2 - 1 mg/mL CLC, and T3 - 1.5 mg/mL CLC. After 18 h of incubation, structures were denuded and transferred to in vitro culture (CIV) for 8 days. Cleavage rate was assessed on the second day (D2), and on the seventh day (D7), embryo classification and blastocyst production rate were evaluated. Additionally, total and apoptotic embryonic cell counts were conducted using differential staining for bovine embryos. Oxidative status was assessed in the FIV and CIV media of each treatment by measuring thiobarbituric acid reactive substances - TBARS. Concentrations of 1.0 mg/mL and 1.5 mg/mL of CLC significantly reduced the proportion of cleaved structures (P = 0.0029), as well as the percentages of cleaved structures and blastocysts (P < 0.001). Moreover, increasing CLC concentrations decreased the total number of embryonic cells (P < 0.001). No significant differences were noticed in other parameters. In conclusion, supplementing cryopreserved Pantaneiro cattle semen with cholesterol-loaded cyclodextrin (CLC) at concentrations of 0.5, 1, and 1.5 mg/mL adversely affects in vitro embryo production.

Gestation length (GL) in horses varies widely, influenced by multiple variables, including maternal, fetal, and environmental factors. This study aimed to investigate and quantify the relative contributions of climatic (photoperiod and temperature-humidity index - [THI]), maternal (age and parity), fetal (sex) and environmental (year and month of foaling) variables influencing gestation length in Thoroughbred mares. Retrospective data encompassing 704 pregnancies across nine breeding seasons in tropical and subtropical Brazilian climates were analyzed. Stepwise regression analysis identified foaling month and year as the primary determinants of gestation length, with additional contributions from foal sex, mare age, parity, and THI. Subsequent multiple regression analysis ranked foaling month, mare age, and foaling year as the most significant factors, while parity, THI, and foal sex demonstrated smaller but statistically significant impacts. Gestation length in Thoroughbred mares is influenced by a complex interplay of environmental, maternal, and fetal factors, with foaling month, mare age, and foaling year being the most critical. These findings provide valuable insights for optimizing breeding management in tropical and subtropical climates.

High-prolific sows have a high incidence of stillbirth and asphyxiated piglets due to calcium deficiencies. Calcium is important for enhancing farrowing efficacy and colostrum production. Calcium chloride (CaCl₂), an acidogenic compound that lowers dietary cation-anion difference (DCAD), promotes calcium mobilization, thereby mitigating the risk of calcium deficiency. The objective of this study was to determine the effects of CaCl₂ supplementation in sows during the transition period in working and non-working hours on sow performances, colostrum quantity and quality, urine pH, serum total calcium, and piglet characteristics. A total of 58 Landrace × Yorkshire crossbred sows and 382 piglets from a commercial swine farm in Thailand were included in the study. These sows were classified into two groups. Control (n = 29) were fed a standard lactation diet without a supplement and CaCl₂ (n = 29) received the same quantity of standard lactation diet with 25 g/day of CaCl₂ from day 109 of gestation until 7 days after farrowing (13.8 ± 0.3 days). The sow performances and farrowing time classified as either during working hours (WH) or non-working hours (NWH) were recorded. The piglet characteristics were classified based on birth order: i.e., 1-7 (n = 182) and ≥8 (n = 200). On average, the total number of piglets born per litter (TB) and the number of piglets born alive per litter (BA) were 15.0 ± 3.2 and 13.5 ± 2.9 piglets/litter, respectively. During NWH, CaCl₂ group had a lower percentage of stillborn piglets per litter (SB) than Control group (5.5 ± 2.0 % vs. 13.9 ± 2.1 %, P = 0.030). While no difference was observed during WH (4.9 ± 2.4 % vs. 3.8 ± 2.2 %, P = 0.988). After supplementation with CaCl₂ for 4 days, CaCl₂ group had a lower urine pH than Control group (5.2 ± 0.1 vs. 6.3 ± 0.1, P < 0.001) but did not differ in the serum total calcium and colostrum quantity and quality (P > 0.05). The piglets in CaCl₂ group required less farrowing assistance than those in Control group, particularly among piglets with birth order 1-7 (17.9 ± 5.7 % vs. 33.9 ± 5.3 %, P = 0.042). The incidence of broken umbilical cord was also lower in CaCl₂ than in Control groups (P < 0.001), with a reduction in birth order 1-7 (30.1 ± 5.8 % vs. 61.1 ± 5.5 %, P < 0.001) and birth order ≥8 (48.2 ± 6.0 % vs. 65.4 ± 5.4 %, P = 0.034). Similarly, the incidence of meconium staining was lower in CaCl₂ than in Control groups (P < 0.001), with a reduction in birth order 1-7 (28.9 ± 6.7 % vs. 70.2 ± 6.2 %, P < 0.001) and birth order ≥8 (63.4 ± 6.8 % vs. 89.2 ± 6.2 %, P = 0.005). In conclusion, CaCl₂ supplementation in sows during the transition period significantly reduces SB, particularly during NWH and improves piglet characteristics at birth.

The aim of this study was to evaluate the use of a long-acting recombinant human FSH (rhFSH, corifollitropin-alpha) to induce ovarian stimulation in Nelore breed (Bos indicus) calves and prepubertal heifers prior to ovum pick-up (OPU) for in vitro embryo production (IVEP). In Experiment 1, a dose-response trial was performed to determine the optimal dose of rhFSH, which was determined to be 10 μg. In Experiment 2, 6-7 mo old calves were randomly allocated to receive rhFSH either via sc (n = 5) or im (n = 5). Ovarian follicular development was monitored daily by transrectal ultrasonography for five days. There was no effect of route (P = 0.1348) nor route × time interaction (P = 0.8336) on follicle development. In Experiment 3, 7-8 mo old calves (n = 90) were randomly allocated into 5 groups: 1) Control: no ovarian stimulation; 2) rhFSH-96: 10 μg rhFSH sc followed by OPU 96h later; 3) rhFSH-120: 10 μg rhFSH sc and OPU 120h later; 4) eCG-96: 300 IU eCG im and OPU 96h later; and 5) eCG-120: 300 IU eCG im and OPU 120h later. Non-rhFSH treated Nelore mature cows (n = 10) were used as reference-controls for IVEP outcomes. Treatment with rhFSH increased the proportion of grade I cumulus-oocyte complexes (COC) collected by OPU at either timepoints (96 or 120h) compared with eCG or controls (P < 0.0001). Blastocyst rate for rhFSH-120 calves was similar to mature cows (P > 0.05). Treatment with rhFSH, however, increased the proportion of expanded COC and decreased the proportion of viable COC (P < 0.0001) compared with eCG and controls. In Experiment 4, yearling heifers (n = 60) were treated or not (control group) with 10 μg rhFSH sc and OPU was performed 72 or 96h later. Heifers treated with rhFSH had a greater proportion of grade I COC (P = 0.0188) and blastocyst rate (P < 0.0098) than controls, regardless of the interval used. These groups, however, yielded a lesser number of viable COC (P = 0.0264), resulting in a similar (P = 0.5869) number of embryos produced by donor per OPU compared with controls. Pregnancy rate after embryo transfer was also similar between controls and rhFSH groups (19.3 vs 25.0 %, P = 0.4142). In summary, treatment with a single sc injection of corifollitropin-alpha was effective to promote ovarian stimulation in calves prior to OPU. The potential benefits of stimulatory protocols using rhFSH, however, have been overshadowed by a decrease in the total number of viable COC recovered per donor, thus failing to increase the number of embryos produced per OPU.

The current study evaluated the impact of dietary curcumin nano-micelles (CNM) on the quality of Longissimus lumborum (LL) muscle in lambs during long-term freezing storage. Thirty-two crossbred male lambs were assigned into four groups receiving 0, 20, 40, or 80 mg CNM daily over a 97-day fattening period. Meat samples were analyzed for quality attributes over nine months of freezing. Supplementation with CNM, especially at 40 mg, improved carcass characteristics and reduced saturated and branched-chain fatty acids. Notably, CNM preserved meat color, enhanced water-holding capacity, and reduced drip and cooking losses, with the 40 mg dosage showing the most significant effects. While meat tenderness was unaffected, CNM exhibited antioxidant properties by reducing lipid peroxidation and stabilizing enzyme activities and total antioxidant capacity. These results indicate that CNM, particularly at 40 mg, enhances meat quality during long-term freezing, especially after six months. The findings underscore CNM's potential as a natural additive to improve lamb meat stability and quality during extended frozen storage, with implications for both the meat industry and consumer satisfaction.

The current narrative review aims to summarize the relation of mitochondrial content (MC) and mitochondrial DNA copy number (MDCN) in spermatozoa with sperm penetrability, and to discuss the various determining factors during the process of spermatogenesis in mammals. There are many potential factors associated with the quantitative alteration of MC and MDCN in male gametes from spermatogenesis to ejaculation. Particularly, spermatogenesis may be the first step to jointly contribute to an incomplete reduction of MC and MDCN in spermatozoon. It appears to be now quite clear that some abnormalities during spermatogenesis and oxidative stress are the main factors highly associated with the quantitative change of MC and MDCN in spermatozoa, consequently affecting sperm quality and their penetrability into oocytes. Currently, a series of proteins contributing to form sperm midpiece during spermatogenesis and cytoplasmic elimination during spermiation have been currently identified. The present review provides insight into how these factors interact with sperm MC and MDCN, and handholds to gain a better understanding of their roles. This review also highlights the uniqueness of normal fertile spermatozoa which have relatively lower MC and MDCN, but have mitochondria that function completely in multiple pivotal physiological pathways.