农林科学最新文献

In the context of agroecological transition, breeding females with robust reproductive performance, leading to prolonged lactation sequences, is valuable for farmers. This study aimed to explore the relationship between artificial insemination (AI) success and phenotypic lactation curves that serve as proxies for key biological functions in Alpine and Saanen goats. Using data from two French experimental farms (1996-2021), the study analyzed time series data on milk yield (MY), body weight (BW), and sternal body condition score (BCS_S). These data were modeled at the lactation scale to characterize dynamic profiles and create clusters. Each phenotypic lactation curve was evaluated with three levels of detail: cluster membership, synthetic indicators, and model parameters. To investigate AI success, three datasets were used: 638 lactations with complete MY, BW, and BCS_S data; 1359 lactations with MY and BW; and separate sets with 1731 MY and 795 BCS_S records. A mixed logistic regression model (year as a random effect) assessed the relationship between AI success and phenotypic lactation curve characteristics. Results showed that for primiparous goats, AI success was influenced by MY clusters (p < 0.05), while in multiparous goats, MY and BCS_S clusters did not influence AI success. However, indicators such as persistency (p < 0.001) and BW repletion speed (p < 0.001) were significant. Overall, the lactation curve shape was more important to AI success than milk production level, offering insights for enhancing reproductive performance in dairy goats.

Energy metabolism homeostasis is essential for oocyte maturation and acquisition of developmental capacity. However, bovine oocyte in vitro maturation (IVM) is highly susceptible to metabolic stress and lipid accumulation. β-Aminoisobutyric acid (BAIBA), a metabolite produced in response to skeletal muscle exercise, has been reported to be involved in lipid and glucose metabolism, as well as inflammation and oxidative stress. This work aimed to evaluate the potential effects of BAIBA on bovine oocyte IVM and its mechanisms. Different concentrations of BAIBA (10, 20, 50, 100, and 200 μmol/L) were supplemented to bovine oocyte IVM medium. Results shown the BAIBA (50 μmol/L) had no effect on the extrusion rate of the first polar body of oocytes but significantly improved the subsequent blastocyst formation rate and embryo quality. Further revealed that supplementing BAIBA significantly up-regulated expression levels of genes to fatty acid β-oxidation metabolism (CPT1A, CPT1B and CPT2), promoted lipid metabolism, lowered lipid content, and improved mitochondrial membrane potential and active mitochondria content. Importantly, BAIBA stimulation significantly increased the phosphorylation of AMP-activated protein kinase (AMPK); and the inhibition of AMPK activity (Compound C, AMPK inhibitor) suppressed the ability of BAIBA to promote lipid metabolism in oocytes. Besides, inhibition of AMPK lowered the oocyte maturation rate and the subsequent zygote cleavage and blastocyst formation rate when compared to that of the BAIBA treatment. The results indicated that BAIBA was mainly involved in promoting lipid catabolism by activation of AMPK, consequently enhancing oocyte development potential.

This study aimed to investigate the performance differences of low-sodium myofibrillar protein (MP) gels substituted by different chloride salt mixtures from the perspective of gelation process. The results revealed that low-sodium MP substituted by KCl/CaCl₂ exhibited higher turbidity and particle size at 40 % substitution, and formed protein aggregates earlier at 53 °C. During the gelation process, KCl/CaCl₂ increased the extent of cross-linking as the substitution level increased from 10 % to 40 %, which was prone to forming final gels with poor palatability. Microstructural and binarization results visually indicated that an irregular reticular structure composed of partial clusters formed when the temperature heated over 53 °C, and the cross-linked cluster blocks further shrunk from 53 °C to 73 °C. Rheological amplitude sweeps revealed that KCl/CaCl₂-substitued MP displayed a faster fracture of the ductile structure, and this influenced the distribution of cluster blocks inside the network. The introduction of salt mixtures altered protein conformation, and more unordered structures were found in low-sodium MP containing CaCl₂, rather than MP containing MgCl₂. Additionally, Ca²⁺ ions increased the thermo-denatured temperature of MP, and extended the relaxation time of bound water at 53 °C, and Mg²⁺ ions slowed down the degree of liquid loss at 53 °C. As a result, the low-sodium MP containing CaCl₂ exhibited a lower expansion of protein structure accompanied by the involvement of less proteins in gel formation and more liquid loss in the final gel.

Salmonella is a foodborne pathogen of global significance and is highly prevalent in pork. This study investigated the prevalence, contamination distribution, virulence genes and antibiotic resistance of Salmonella in 3 pork processors in the Shandong Province of China. Samples were collected from 13 different sampling sources across the slaughter procedures (600 samples) as well as at retail outlets supplied by these processors (45 samples). The prevalence was 18.9 % among all the samples, with the highest prevalence observed in feces (40.0 %), lairage pens (38.0 %), and hides (34.0 %). A total of 6 serotypes were identified, with S. Rissen (46.3 %) and S. typhimurium (32.0 %) found to be the most prevalent serotypes. 86.8 % of Salmonella isolates were multi-drug resistant, with the majority of strains resistant to erythromycin, sulfisoxazole, and ampicillin. The multilocus sequence typing analysis revealed 6 STs were obtained from 45 isolates, with the dominant type ST469 accounting for 40.0 % of the total, which suggested a high possibility of cross-contamination between the plant processing chain and retail outlets. This work reveals the prevalence and correlation of Salmonella isolates between pork slaughter and retail outlets and acts as a case-study for stakeholders wishing to improve pork supply chain hygiene, control cross-contamination between the various slaughtering processes, and obtain continuous updates on Salmonella surveillance.

Dry-cured ham is a traditional Mediterranean meat product consumed throughout the world. This product is very variable in terms of composition and consumer's acceptability is influenced by different factors, among others, visual intramuscular fat and its distribution across the slice, also known as marbling. On-line inter and intramuscular fat evaluation and marbling assessment is of interest for classification purposes at the industry. Currently, this assessment can only be performed by visual inspection and traditional sensory panels. The current work presents the software MarblingPredictor, which predicts the marbling score of the three most representative ham muscles from square regions of interest automatically extracted from a ham slice. It also estimates the rate of subcutaneous and intermuscular fat content in the ham slice. Using MarblingPredictor, the mean absolute error between the true and predicted marbling scores was 0.53, very similar to the error of sensory panellist, which is 0.50. The correlation between the computer and sensory scores is 0.68, which means a moderate to good recognition. This result underscores the relevance of this tool for its application in the ham industry for quality control and categorization purposes. As part of this work, we also present the dataset HamMarbling of annotated ham slices used to train and test the software with the marbling scores provided by the panellists. The MarblingPredictor software and images are available from https://citius.usc.es/transferencia/software/marblingpredictor for Windows- and Linux-based systems for research purposes.

The World Health Organization set a goal of reducing salt intake by 30 % by 2025. This study investigates the impact of replacing 33 % NaCl with KCl and microencapsulated spices and aromatic plant extracts (ME) in a dry-cured meat sausage (CMS). Microbial, physico-chemical, and sensory analyses were conducted throughout processing and storage. Three batches of CMS were prepared with four formulations: Control (1.5 % NaCl), F1 (1 % NaCl, 0.5 % KCl), F2 (1 % NaCl, 0.5 % ME, 0.3 % KCl), and F3 (1 % NaCl, 0.5 % ME). The absence of Listeria monocytogenes was confirmed. The formulations did not affect the growth of lactic acid bacteria (7.8 log cfu/g), Enterococci (6.5 log cfu/g), and coagulase-negative staphylococci (5.6 log cfu/g). Biogenic amines increased significantly (P < 0.05) during storage, with cadaverine (from 166 to 456 mg/kg), tyramine (163 to 424 mg/kg) and putrescine (from 31.0 to 90.5 mg/kg), being the most abundant. All low sodium CMS had lower TBARS values (F1 = 0.59 mg MDA/kg, F2 = 0.56 mg MDA/kg and F3 = 0.47 mg MDA/kg) compared to control (0.78 mg MDA/kg). Colour parameters lightness (L*) and yellowness (b*) remained stable (P > 0.05) while sausages with KCl and/or ME were redder. CMS F1 was considered with the ideal saltiness by 54 % consumers, that is usually considered enough to launch the product in the market. The use of ME in CMS has potential but still requires optimization. The study demonstrates that a 33 % NaCl replacement with KCl is feasible without jeopardize the organoleptic characteristics or safety of CMS.

This study examined the effect of supplementation of freezing extender with isoglycyrrhizin (ISL), a natural antioxidant agent, on the quality and fertility potential of goat spermatozoa after cryopreservation. Forty ejaculates were collected from eight Chongming White rams and diluted with five concentrations of ISL: 0 (control group), 50, 100, 150, and 200 μg/mL. The quality, motility parameters, antioxidant properties, mRNA expression of antioxidant and ferroptosis genes, and ability to induce fertilization, were evaluated following freezing/thawing. Total motility and progressive motility were significantly increased in spermatozoa following the addition of 150 and 200 μg/mL ISL. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities were enhanced in all ISL-supplemented groups compared to controls. Adding ISL decreased the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and nitric oxide (NO). mRNA levels of ferroptosis-related genes, voltage-dependent anion channel protein 2 (VDAC2), voltage-dependent anion channel protein 3 (VDAC3), protein 53 (P53), and nuclear factor erythroid 2-related factor 2 (NRF2) tended to decrease after adding ISL, whereas the levels of antioxidant genes glutathione peroxidase 4 (GPX4) and glutathione peroxidase 4 (GPX5), tended to increase. The best spermatozoa quality and the strongest antioxidant properties were obtained after adding 150 μg/mL ISL. Therefore, fresh semen, frozen semen, and frozen semen with 150 μg/mL ISL was used for in vitro fertilization of oocytes. The cleavage and blastocyst rates were significantly lower in frozen semen compared with fresh semen, whereas frozen semen containing 150 μg/mL ISL showed a significant increase in cleavage and blastocyst rates compared with frozen semen. In conclusion, ISL can be used as an antioxidant in goat semen cryodilution, and the addition of ISL can improve the quality and antioxidant properties of frozen and thawed spermatozoa. ISL can also protect the ability of spermatozoa to be fertilized and develop; 150 μg/mL ISL was the optimal concentration for addition.

This study aimed to understand the development of pale, soft, and exudative (PSE) pork from a new perspective by comparing the differences of lactate-induced protein lactylation and its potential regulators including E1A binding protein p300 (p300) and cAMP response element binding protein (CBP) between PSE and red, firm, and non-exudative (RFN) pork at 1 h postmortem. Results demonstrated that PSE pork presented lower glycogen contents and higher lactate levels than RFN pork (P < 0.05). Meanwhile, p300/CBP and protein lactylation levels in PSE pork were higher (P < 0.05). Besides, the immunofluorescence results showed that p300/CBP and lactylated proteins were predominantly localized around the nucleus and sarcolemma membrane with small amounts in the cytoplasm, and these distribution signals were intensified in PSE pork. Importantly, a high degree of co-localization of p300/CBP and lactylated proteins was also observed in postmortem myocytes, confirming that p300/CBP were the critical regulators of lactylation modification in postmortem muscle. This work for the first time demonstrates that protein lactylation levels between PSE and RFN pork were notably diverse, which may potentially be involved in the regulation of various postmortem muscle biochemical metabolism.

The effect of partial replacement of cereals by increasing levels of almond hulls (AH) was tested in twenty-four lambs distributed into three dietary treatments: 1) diet without replacement of cereals with AH (0AH); 2) diet with replacement of cereals with 9% of AH (9AH); and 3) diet with replacement of cereals with 18% of AH (18AH). All diets included 40% dehydrated lucerne and 5% soybean oil. Dry matter intake, growth performance, feed costs, carcass traits, meat quality, and lipid oxidative stability of raw and cooked meat during refrigerated storage were evaluated. Replacing part of the cereal with AH up to 18% did not affect the average daily gain but increased quadratically the feed conversion ratio and tended to decrease linearly the slaughter live weight. Diet cost per kg live weight gain was affected quadratically, with similar feed costs in 0AH and 18AH diets. The carcass and meat quality parameters were not affected by diet, except meat shear force that linearly reduced with the inclusion of AH in diets, meat flavour acceptability that showed lower values in 9AH diet, and lipid stability. Lipid oxidation increased in raw and cooked meat during storage, but the 18AH diet resulted in lower lipid oxidation in cooked meat than the other diets. Replacing part of the cereal with AH up to 18% in diets composed of 40% forage shown to be a dietary strategy applicable to fattening lamb, allowing high productive performances without relevant impact on feed costs, and improving lipid stability of cooked meat.

In this study, emulsions co-encapsulated with Bifidobacterium bifidum (B. bifidum) and quercetin (BQE) were prepared, and the encapsulation efficiency, antioxidant properties, storage stability, and digestive stability of emulsions containing different concentrations of quercetin were investigated. The results indicate that the prepared emulsion possesses excellent encapsulation efficiency and stability at quercetin concentration of 500 μg/mL. After in vitro digestion, the survival of B. bifidum improved, and the bioaccessibility of quercetin increased to 40.76 ± 1.10 % compared with that of free quercetin (25.16 ± 1.79 %). In addition, the emulsions were also combined with sodium alginate (SA) coating and applied to Harbin red sausage for storage. The results demonstrate that the coating exhibits certain antioxidant and aerobic bacterium-inhibiting effects. The moisture content of 1.5 %-BQE-SA coating was 42.48 % at 12 d, which was 4.14 % more than that of the control. The pH, color, and texture of Harbin red sausage were effectively preserved, successfully extending its shelf life by at least 3 days. Therefore, this study offers new insights into improving the stability of B. bifidum and quercetin, which can be employed to improve the quality of Harbin red sausage during storage.