Uterine tissue nutrients are nutrients secreted by the uterus during animal reproduction， including amino acids， proteins， lipids， sugars， and other metabolites. Before implantation， the embryo relies on the tissue nutrients secreted by the uterus for nutrition. Their secretion is dynamically regulated by the estrous cycle， pregnancy status， uterine health， and maternal nutritional status. This article summarizes the changes in uterine fluid tissue nutrients under the estrous cycle， pregnancy status， nutritional levels， and endometritis. Through the study of these patterns， a more favorable uterine environment can be provided for the early development of embryos.

The evaluation of blastocyst quality is of great significance for assisted reproductive technology （ART）. Through quality assessment， blastocysts with the highest implantation potential can be selected， reducing the number of embryo transfers and improving the clinical pregnancy rate. However， there are many methods for blastocyst quality evaluation， but there is a lack of horizontal and systematic comparison. At present， the existing blastocyst quality evaluation methods mainly include morphological evaluation， metabolomics， time-lapse monitoring technology， genetic screening technology， artificial intelligence technology， etc. This paper systematically describes and compares the most effective and widely used methods for evaluating the quality of blastocysts at the blastocyst stage by summarizing the existing research systems and comprehensively discussing the advantages and limitations of various blastocyst quality evaluation technologies. Meanwhile， optimization schemes are proposed according to the limitations of various methods. It provides a theoretical basis and technical support for further optimizing the blastocyst quality evaluation technology， improving the clinical pregnancy rate and enhancing the efficiency of embryo selection.

Antibiotics once played an essential role in the process of China’s livestock industry. With the continuous increase in people’s attention to food safety and ecological environment issues， the adverse effects of antibiotic abuse have gradually become prominent. China’s feed industry has ushered in an era of a complete ban on antibiotics， and the livestock industry is facing significant challenges. Probiotics， as feed additive with great potential， can affect the composition of the intestinal flora after being ingested by animals， improve the intestinal barrier and regulate the immune response， showing unique advantages and value. It is expected to replace antibiotics and play a role in the livestock industry. Enterococcus faecalis， as a member of the lactic acid bacteria group， can be used as a feed additive and has attracted much attention. Enterococcus faecalis has relatively strong resistance to the environment， and its biological characteristics determine whether it can reach the host’s intestinal tract with a certain number of viable bacteria， and then determine whether this bacterium can be widely used in the livestock industry. As an active microorganism beneficial to the host， Enterococcus faecalis can regulate the balance of the body’s intestinal flora， enhance the function of the intestinal epithelial barrier， promote the metabolism of nutrients， and enhance the body's immunity. There is an increasing number of studies on the impact of Enterococcus faecalis on livestock and poultry. It has shown positive effects such as improving production performance， reducing the incidence of diarrhea and mortality， and enhancing the immune system in various livestock and poultry， including pigs， cattle， sheep， and chickens. This bacterium can optimize the digestive function of livestock and poultry， improve feed efficiency， and thus increase the economic benefits of farms. Its application range in the livestock industry is also constantly expanding. This article focuses on Enterococcus faecalis， summarizes its application in livestock and poultry in recent years， and reviews its biological characteristics， mechanisms of action， applications in the livestock and poultry industry， and the existing problems of Enterococcus faecalis. The aim is to provide a new insights from previous research about this bacterium and its impact in the livestock and poultry industry.

The gastrointestinal tract is not only a place where nutrients digest， absorb and metabolize， but also serves as both a primary source and a major target of reactive oxygen species （ROS）. Intestinal health is a cornerstone of animal growth and a critical determinant of livestock production efficiency. Tryptophan， an essential amino acid， is metabolized by both host cells and gut microbiota into various bioactive compounds， such as indole， kynurenine and 5-hydroxytryptamine. These metabolites act as endogenous ligands to regulate intestinal oxidative stress and inflammatory damage. This review summarizes the host and microbial pathways of intestinal tryptophan metabolism， explores the physiological functions of tryptophan metabolites in modulating oxidative stress and tissue repair， and discusses the role of microbial tryptophan metabolism in potential nutritional interventions，including probiotics and nutritional supplements. These findings aim to inform research on nutritional strategies for managing gut health.

Fucoidan is a water-soluble polysaccharide derived from brown algae， which possess anti-inflammatory， antioxidant， antiviral， and immunomodulatory function， and also has a protective effect on the intestinal barrier. It has shown promise as a novel additive in animal production. This article reviews the structure， extraction methods， physiological functions， factors affecting biological activity， protective effects on the intestinal barrier， and applications in poultry and livestock production of fucoidan.

Feed accounts for 60% to 70% of costs in pig and poultry production. The technology of diversified diets with low protein and low soybean meal is critical to reduce feed costs and relieve the pressure on the supply of feed grains such as corn and soybean meal. Accurate nutritional values are the keystone to determine the substitutability of various feed ingredients and to formulate diversified diets with low protein and low soybean meal. To obtain accurate nutritional values for feedstuffs in practice， it is critical to establish dynamic nutritional value database for feed ingredients by developing precise and rapid evaluation technologies. Thereby， this article systemically discusses the importance and broad application of simulated digestion technique in nutritional evaluation for feedstuffs from three aspects： the principles of establishing nutritional values database for feed ingredients， the progress in simulated digestion technique for feedstuff evaluation， and the application of simulated digestion technique in feedstuff database establishment and substitutability determination.

N6-methyladenosine （m⁶A） modification and microRNAs （miRNAs） are important factors in gene expression regulation， playing a crucial role in cellular energy metabolism. m⁶A modification participates in various physiological and pathological processes by regulating RNA stability， splicing and translation. miRNAs， as a class of small molecule RNAs， directly affect cellular metabolic pathways by targeting and regulating gene expression. The m⁶A modification-mediated regulation of miRNAs plays a pivotal role in cellular energy metabolism， especially in regulating metabolic processes such as glycolysis and mitochondrial function. By discussing the regulatory effect of m⁶A modification on miRNAs and its impact on energy metabolism， this review elaborating in detail on the mechanism by which m⁶A modification affects cellular energy metabolism by regulating miRNAs， and reveals the possibility of m⁶A modified miRNAs as targets for regulating cellular energy metabolism， in order to provide a theoretical reference for regulating animal growth and development and treating energy metabolism-related diseases.

The RNA genome of coronavirus contains multiple open reading frames， coding for structural proteins， non-structural proteins， as well as accessory proteins. The accessory proteins of coronavirus are species specific， and the amounts of accessory proteins differ between the species. Coronavirus accessory proteins are not necessary for viral replication， but some of them are involved in the host immune response， viral pathogenesis and virus virulence. Research on coronavirus accessory proteins will provide new potential targets for the development of therapeutic drugs and theoretical guidance for disease prevention and treatment. In this paper， the functions of several representative accessory proteins of coronaviruses are reviewed. It focuses on the relationship between accessory proteins and virus-host interactions， including the role of accessory proteins in promoting host cell apoptosis， host innate immune regulation， and pathogenicity in the host. This will help to investigate the infection and pathogenesis of coronavirus， and provide reference for developing new vaccines and antiviral drugs.

Salmonella is a common foodborne pathogen worldwide. With the promotion and use of antibiotics， more and more Salmonella produce or acquire antibiotic resistance genes （ARG） through vertical transmission and horizontal gene transfer （HGT）， causing widespread dissemination of antibiotic resistance. In the process of horizontal gene transfer， ARGs are mainly carried by mobile genetic elements （MGEs）， which are important mediators of HGT and can facilitate the spread of ARGs. Among them， MGEs mainly include plasmids， integrons and conjugative elements， transposons， insertion sequences， and phages， etc. MGE-associated transfer mechanisms， accessory gene compositions， and relationships between ARG dissemination and animal sources and geographic environments vary. The aim of this review is to outline the HGT mechanism of ARG in Salmonella， the different MGE-mediated HGT mechanisms and the influencing factors of HGT occurrence and development， which is of great significance for the in-depth investigation of the HGT mechanism of drug resistance in Salmonella.

The purpose of this study was to analyze the differences of production performance， meat quality traits and serum biochemical indicators between Yushan black pigs and its two-way cross pigs， and provide the reference for the hybrid utilization of Yushan black pig. In this study， the healthy Yushan black pigs and its two-way cross pigs were used and divided into 4 groups which included YY， DY， BY and SY with 3 replicates with 5 individuals per replicate. All of the experimental pigs were uniformly castrated and fattened with same body weight， the feed nutritional level and feeding management were consistent. When the pigs were raised until 250 days， each group selected 8 individuals （half castrated male and half castrated female） for slaughter， and serum was collected to detect biochemical indicators. The results showed that： 1） The average daily gain （ADG） of DY at the early fattening period was highest， the ADG of BY at the late fattening period was highest， the ADG of BY at the entire fattening period was the highest， and ADG of the 3 hybrid groups at the entire fattening period was significantly higher than that of YY group （P<0.01）. 2） The feed conversion ratio （FCR） of YY at the early fattening period was significantly higher than that of DY （P<0.01） and BY （P<0.05）， and the FCR of YY at the late fattening period was significantly higher than that of BY （P<0.01）， the FCR of YY at the entire fattening period was the highest and BY was the lowest. 3） The ADG of BY at the late fattening period was higher than that at the early fattening period （P<0.05）， while the ADG of other 3 groups were not different between the early fattening period and late fattening period （P>0.05）. 4） The FCR of the 4 groups at the late fattening period were significantly higher than that at the early fattening period （P<0.05）. 5） The slaughter performance of the 3 hybrid groups were significantly improved compared to the YY group. 6） The correlation analysis results found that， there was a significant positive correlation （P<0.05） between most slaughter traits and between slaughter traits and fattening traits， but there was a significant negative correlation （P<0.05） between ADG at early fattening period and fat percentage （P<0.05）. 7） The intramuscular fat content of YY was significantly higher than that of BY and SY （P<0.01）， the marbling score of DY was significantly higher than that of BY （P<0.05）， the drip loss of SY was significantly higher than that of YY and DY （P<0.01）， the shear force of BY was significantly higher than that of YY （P<0.01）， and the cooked meat percentage of BY was significantly higher than that of SY （P<0.01）. 8） There was no significant difference （P>0.05） in the level of serum immune indicators， CAT， T-AOC and blood lipid indicators between YY group and 3 hybrid groups. However， the serum GSH-Px level of YY group was significantly lower than that in SY group （P<0.01）， the serum MDA level was significantly higher than that in DY group （P<0.01）， the serum SOD level was significantly higher than that in SY group （P<0.05）， and the GLU level was significantly lower than that in BY （P<0.05） and SY （P<0.01） groups. In summary， the important production indicators such as growth and development traits， FCR and slaughter performance were significantly improved but the meat quality traits were decreased in these 3 hybrid groups compared to Yushan black pigs， while the immune and antioxidant ability were not significantly changed. The study results showed that， the DY and BY two-way cross combination were more suitable for the hybrid utilization of Yushan black pig.