Journal of Animal Science and Biotechnology最新文献

Probiotic extracellular vesicles (pEVs) are biologically active nanoparticle structures that can regulate the intestinal tract through direct or indirect mechanisms. They enhance the intestinal barrier function in livestock and poultry and help alleviate intestinal diseases. The specific effects of pEVs depend on their internal functional components, including nucleic acids, proteins, lipids, and other substances. This paper presents a narrative review of the impact of pEVs on the intestinal barrier across various segments of the intestinal tract, exploring their mechanisms of action while highlighting the limitations of current research. Investigating the mechanisms through which probiotics operate via pEVs could deepen our understanding and provide a theoretical foundation for their application in livestock production.

Background: Exogenous gonadotropin-controlled ovarian stimulation is the critical step in animal reproductive management, such as pig, sheep, bovine and other species. It helps synchronize ovulation or stimulate multiple ovulations. However, a number of evidence indicated an unexpected decrease in pregnancy outcomes following ovarian stimulation. This study aimed to explore the underlying mechanism of the pregnancy defect and develop a practical rescue strategy.

Results: Compared with those in the control group, gilts that underwent ovarian stimulation showed a decrease in pregnancy rate, farrowing rate, and total number of piglets born. Stimulated gilts also showed an increase in estradiol (E₂) levels. The supraphysiological E₂ level was correlated with the decrease in the number of piglets born. Furthermore, we found that high levels of E₂ impair uterine receptivity, as shown by the overproliferation of endometrial epithelial cells. In vitro mechanistic studies demonstrated that high levels of E₂ hyperactivate FGF-FGFR-ERK signaling cascade in the uterine endometrium, and in turn induces overproliferation of endometrial epithelial cells. Of note, N-acetyl-L-cysteine (NAC) supplementation effectively inhibits ERK hyperphosphorylation and ameliorates endometrial epithelial overproliferation. Importantly, in vivo experiments indicated that dietary NAC supplementation, compared with ovarian stimulation group, improves the uterine receptivity in gilts, and significantly increases the pregnancy rate and total number of piglets born.

Conclusions: Ovarian stimulation-induced supraphysiological levels of E₂ impairs uterine receptivity by hyperactivating FGF-FGFR-ERK signaling cascade, thereby reducing pregnancy rate and litter size. Supplementing NAC to a conventional diet for gilts ameliorates hyperactivated ERK signaling and improves uterine receptivity, thus rescuing adverse pregnancy outcomes following ovarian stimulation.

Background: Follicular atresia significantly impairs female fertility and hastens reproductive senescence. Apoptosis of granulosa cells is the primary cause of follicular atresia. Pyroptosis and necroptosis, as additional forms of programmed cell death, have been reported in mammalian cells. However, the understanding of pyroptosis and necroptosis pathways in granulosa cells during follicular atresia remains unclear. This study explored the effects of programmed cell death in granulosa cells on follicular atresia and the underlying mechanisms.

Results: The results revealed that granulosa cells undergo programmed cell death including apoptosis, pyroptosis, and necroptosis during follicular atresia. For the first time, we identified the formation of a PANoptosome complex in porcine granulosa cells. This complex was initially identified as being composed of ZBP1, RIPK3, and RIPK1, and is recruited through the RHIM domain. Additionally, we demonstrated that caspase-6 is activated and cleaved, interacting with RIPK3 as a component of the PANoptosome. Heat stress may exacerbate the activation of the PANoptosome, leading to programmed cell death in granulosa cells.

Conclusions: Our data identified the formation of a PANoptosome complex that promoted programmed cell death in granulosa cells during the process of follicular atresia. These findings provide new insights into the molecular mechanisms underlying follicular atresia.

The absence of trace amounts of natural bioactive compounds with important biological activities in traditional dietary models for global farm animals, coupled with an incomplete theoretical system for animal nutrition, has led to unbalanced and inadequate animal nutrition. This deficiency has adversely impacted animal health and the ecological environment, presenting formidable challenges to the advancement of the swine breeding industry in various countries around the world toward high-quality development. Recently, due to the ban of antibiotics for growth promotion in swine diets, botanical active compounds have been extensively investigated as feed additives. Polyphenols represent a broad group of plant secondary metabolites. They are natural, non-toxic, pollution-free, and highly reproducible compounds that have a wide range of physiological functions, such as antioxidant, anti-inflammatory, immunomodulatory, antiviral, antibacterial, and metabolic activities. Accordingly, polyphenols have been widely studied and used as feed additives in swine production. This review summarizes the structural characteristics, classification, current application situation, general properties of polyphenols, and the latest research advances on their use in swine production. Additionally, the research and application bottlenecks and future development of plant polyphenols in the animal feed industry are reviewed and prospected. This review aims to stimulate the in-depth study of natural plant polyphenols and the research and development of related products in order to promote the green, healthy, and high-quality development of swine production, while also providing ideas for the innovation and development in the theoretical system of animal nutrition.

Background: Extracellular vesicles (EVs) regulate cell metabolism and various biological processes by delivering specific proteins and nucleic acids to surrounding cells. We aimed to investigate the effects of the cargo contained in EVs derived from adipose-derived stem cells (ASCs) on the porcine embryonic development.

Methods: ASCs were isolated from porcine adipose tissue and characterized using ASC-specific markers via flow cytometry. EVs were subsequently extracted from the conditioned media of the established ASCs. These EVs were added to the in vitro culture environment of porcine embryos to observe qualitative improvements in embryonic development. Furthermore, the proteins within the EVs were analyzed to investigate the underlying mechanisms.

Results: We observed a higher blastocyst development rate and increased mitochondrial activity in early stage embryos in the ASC-EVs-supplemented group than in the controls (24.8% ± 0.8% vs. 28.6% ± 1.1%, respectively). The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay of blastocysts also revealed significantly reduced apoptotic cells in the ASC-EVs-supplemented group. Furthermore, through proteomics, we detected the proteins in ASC-EVs and blastocysts from each treatment group. This analysis revealed a higher fraction of proteins in the ASC-EVs-supplemented group than in the controls (1,547 vs. 1,495, respectively). Gene analysis confirmed that ASC-EVs showed a high expression of tyrosine-protein kinase (SRC), whereas ASC-EVs supplemented blastocysts showed a higher expression of Cyclin-dependent kinase 1 (CDK1). SRC is postulated to activate protein kinase B (AKT), which inhibits the forkhead box O signaling pathway and activates CDK1. Subsequently, CDK1 activation influences the cell cycle, thereby affecting in vitro embryonic development.

Conclusion: ASC-EVs promote mitochondrial activity, which is crucial for the early development of blastocysts and vital in the downregulation of apoptosis. Additionally, ASC-EVs supply SRC to porcine blastocysts, thereby elongating the cell cycle.

Background: Dietary lysine and apparent nitrogen-corrected metabolizable energy (AMEn) are two key variables affecting the production of breeder hens. In this study, the effects and interactions of lysine and AMEn on yellow-feathered broiler breeder hens were investigated. A total of 720 30-week-old breeder hens were fed in a 5 (lysine: 0.56%, 0.68%, 0.80%, 0.92%, and 1.04%) × 2 (AMEn: 11.50 and 11.10 MJ/kg) factorial arrangement for 12 weeks. The productive performance, reproductive traits, biochemical variables of breeder hens, the amino acid concentration and quality of eggs, and the growth performance of offspring broilers were determined.

Result: (1) Dietary lysine had quadratic effects (P < 0.05) on laying rate, average daily egg mass and feed intake/egg mass of breeder hens; birds with 11.50 MJ/kg AMEn (high AMEn) had higher (P < 0.05) BW than those with 11.10 MJ/kg AMEn (low AMEn); (2) dietary lysine significantly affected on the relative ovarian weight (quadratic and linear), and numbers of large yellow follicles (LYF, quadratic); birds with high AMEn had longer fallopian tube and more LYF than those with low AMEn (P < 0.05); (3) dietary lysine had significant effects (linear and quadratic) on eggshell thickness and shell strength of eggs from breeder hens; birds with high AMEn had thinner eggshells and deeper yolk color than those with low AMEn (P < 0.05); (4) there were higher (P < 0.05) contents of protein and concentrations of all measured animo acids (AAs) in eggs from birds fed low AMEn; (5) supplementation with high AMEn to breeder hens significantly increased the hatchability of fertilized eggs; (6) neither dietary lysine level or AMEn affected growth performance of offspring broilers; (7) both dietary lysine level and AMEn significantly affected gonadotropin concentrations and biochemical variables of breeder hens.

Conclusions: Dietary lysine had significant influences on productive performance, reproductive traits, and egg quality of yellow-feathered breeder hens. Based on productive performance, the optimal levels of dietary lysine were 0.81% to 0.83%, while 0.71% to 72% lysine was enough to obtain the best quality of breeding eggs. High AMEn was more beneficial to breeder hens for reproductive traits and hatchability of the fertilized eggs, while it showed detrimental effects on eggshell thickness and AA concentrations of breeding eggs.

Background: Sperm cryopreservation is widely used in the cattle industry, as it allows for disassociating the localization of sires and the collection of semen from the timing of artificial insemination. While freeze-thawing is known to impair sperm DNA integrity, whether the damage induced consists of single- (SSB) or double-strand breaks (DSB) has not been determined. In addition, no previous study has addressed if DNA breaks preferentially reside in specific genome regions such as those forming the toroid linker regions, or are rather spread throughout the regions linked to protamines. The main aim of the present work, therefore, was to elucidate the type and localization of the DNA damage generated by cryopreservation and to evaluate its impact on artificial insemination outcomes in cattle.

Results: The incidence of SSB and DSB was evaluated in 12 ejaculates before and after cryopreservation with the Comet assay, and the localization of the DNA breaks was assessed using pulsed-field gel electrophoresis (PFGE). Before cryopreservation, the incidence of SSB was 10.99% ± 4.62% and involved 20.56% ± 3.04% of sperm cells, whereas these figures significantly (P < 0.0001) increased up to 34.11% ± 3.48% and 53.36% ± 11.00% in frozen-thawed sperm. In contrast, no significant differences in the incidence of DSB were observed (P > 0.990) before and after cryopreservation (before: incidence of 13.91% ± 1.75% of sperm DNA affecting 56.04% ± 12.49% of sperm cells; after: incidence of 13.55% ± 1.55% of sperm DNA involving 53.36% ± 11.00% of sperm cells). Moreover, PFGE revealed that the percentage of sperm DNA fragments whose length was shorter than a toroid (< 31.5 kb) was greater (P < 0.0001) after (27.00% ± 4.26%) than before freeze-thawing (15.57% ± 4.53%). These differences indicated that the DNA breaks induced by cryopreservation affect the regions condensed in protamines, which are structured in toroids. On the other hand, in vivo fertility rates were associated to the incidence of SSB and DSB in frozen-thawed sperm (P = 0.032 and P = 0.005), but not with the size of the DNA fragments resulting from these breaks (P > 0.05).

Conclusion: Cryopreservation of bovine sperm generates single-strand DNA breaks, which are mainly located in protamine-condensed toroidal regions. The incidence of DNA breaks in cryopreserved sperm has an impact on cattle fertility, regardless of the size of generated fragments.

Background: Enterotoxigenic Escherichia coli (E. coli) is a threat to humans and animals that causes intestinal disorders. Antimicrobial resistance has urged alternatives, including Lactobacillus postbiotics, to mitigate the effects of enterotoxigenic E. coli.

Methods: Forty-eight newly weaned pigs were allotted to NC: no challenge/no supplement; PC: F18⁺ E. coli challenge/no supplement; ATB: F18⁺ E. coli challenge/bacitracin; and LPB: F18⁺ E. coli challenge/postbiotics and fed diets for 28 d. On d 7, pigs were orally inoculated with F18⁺ E. coli. At d 28, the mucosa-associated microbiota, immune and oxidative stress status, intestinal morphology, the gene expression of pattern recognition receptors (PRR), and intestinal barrier function were measured. Data were analyzed using the MIXED procedure in SAS 9.4.

Results: PC increased (P < 0.05) Helicobacter mastomyrinus whereas reduced (P < 0.05) Prevotella copri and P. stercorea compared to NC. The LPB increased (P < 0.05) P. stercorea and Dialister succinatiphilus compared with PC. The ATB increased (P < 0.05) Propionibacterium acnes, Corynebacterium glutamicum, and Sphingomonas pseudosanguinis compared to PC. The PC tended to reduce (P = 0.054) PGLYRP4 and increased (P < 0.05) TLR4, CD14, MDA, and crypt cell proliferation compared with NC. The ATB reduced (P < 0.05) NOD1 compared with PC. The LPB increased (P < 0.05) PGLYRP4, and interferon-γ and reduced (P < 0.05) NOD1 compared with PC. The ATB and LPB reduced (P < 0.05) TNF-α and MDA compared with PC.

Conclusions: The F18⁺ E. coli challenge compromised intestinal health. Bacitracin increased beneficial bacteria showing a trend towards increasing the intestinal barrier function, possibly by reducing the expression of PRR genes. Lactobacillus postbiotics enhanced the immunocompetence of nursery pigs by increasing the expression of interferon-γ and PGLYRP4, and by reducing TLR4, NOD1, and CD14.

Background: Aflatoxin B₁ (AFB₁) is a prevalent contaminant in agricultural products, presenting significant risks to animal health. CotA laccase from Bacillus licheniformis has shown significant efficacy in degrading mycotoxins in vitro test. The efficacy of Bacillus CotA laccase in animals, however, remains to be confirmed. A 2 × 2 factorial design was used to investigate the effects of Bacillus CotA laccase level (0 or 1 U/kg), AFB₁ challenge (challenged or unchallenged) and their interactions on ducks. The purpose of this study was to evaluate the efficacy of Bacillus CotA laccase in alleviating AFB₁ toxicosis of ducks.

Results: Bacillus CotA laccase alleviated AFB₁-induced declines in growth performance of ducks accompanied by improved average daily gain (ADG) and lower feed/gain ratio (F/G). Bacillus CotA laccase ameliorated AFB₁-induced gut barrier dysfunctions and inflammation testified by increasing the jejunal villi height/crypt depth ratio (VH/CD) and the mRNA expression of tight junction protein 1 (TJP1) and zonula occluden-1 (ZO-1) as well as decreasing the expression of inflammation-related genes in the jejunum of ducks. Amino acid metabolome showed that Bacillus CotA laccase ameliorated AFB₁-induced amino acid metabolism disorders evidenced by increasing the level of glutamic acid in serum and upregulating the expression of amino acid transport related genes in jejunum of ducks. Bacillus CotA laccase ameliorated AFB₁-induced liver injury testified by suppressing oxidative stress, inhibiting apoptosis, and downregulating the expression of hepatic metabolic enzyme related genes of ducks. Moreover, Bacillus CotA laccase degraded AFB₁ in digestive tract of ducks, resulting in the reduced absorption level of AFB₁ across intestinal epithelium testified by the decreased level of AFB₁-DNA adduct in the liver, and the reduced content of AFB₁ residues in liver and feces of ducks.

Conclusions: Bacillus CotA laccase effectively improved the growth performance, intestinal health, amino acid metabolism and hepatic aflatoxin metabolism of ducks fed AFB₁ diets, highlighting its potential as an efficient and safe feed enzyme for AFB₁ degradation in animal production.

Background: Oxidative stress significantly impacts growth performance and liver function in piglets. Ferulic acid (FA) works as an antioxidant, however, the role and mechanism of FA in the regulation of diquat-induced oxidative stress in piglets are less known. This study was designed to investigate the effects of FA on growth performance and antioxidant capacity in piglets with diquat challenge.

Methods: Thirty-two healthy DLY (Duroc × Landrace × Yorkshire) piglets (13.24 ± 0.19 kg) were randomly divided into one of two diets including 0 or 4 g/kg FA for 14 d. On d 15, all pigs were intraperitoneally injected diquat or sterile saline.

Results: Dietary supplementation with ferulic acid (FA) significantly improved the average daily gain (ADG) and decreased feed-gain ratio (F/G) of piglets. Here, dietary FA supplementation reduced serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) activities in diquat challenged piglets. Furthermore, diquat infusion increased reactive oxygen radicals (ROS) level in liver, decreased the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and increased malondialdehyde (MDA) content in the liver and serum. Supplementation with FA significantly increased T-AOC and T-SOD activities and decreased MDA and ROS levels. FA down-regulated gene and protein expression of Keap1, and up-regulated protein expression of Nrf2 and HO-1 in the liver of piglets with diquat challenge. Importantly, diquat challenge increased the ratio of late apoptosis, increased serum levels of IL-1β, IL-18 and lactate dehydrogenase (LDH), and up-regulated pyroptosis-related genes in the liver. FA supplementation reduced the ratio of late apoptosis and down-regulated mRNA expression of Caspase-1. Accordingly, FA addition reduced concentration of IL-1β, IL-18, and LDH under diquat challenge.

Conclusions: Diquat-induced oxidative stress reduced growth performance and impaired liver function in piglets. Dietary FA supplementation enhanced the antioxidant capacity and reduced the degree of hepatocyte pyroptosis, thereby alleviating the oxidative damage in the liver and mitigating the impact of diquat on growth performance of piglets.