[Objective] This study was conducted to preliminarily explore the possible regulative mechanisms underlying yellow beef fat of local cattle in Hulun Buir City of Inner Mongolia. [Method] A total of 72 local cattle were selected from Hulun Buir City, and their subcutaneous fat and liver tissues were sampled. The subcutaneous fat samples were subjected to color scoring with a 5-point subjective scoring scheme. Using liver tissues as experimental materials, the penta-primer amplification refractory mutation system （PARMS） was employed to assess the genotype and gene frequency distribution of BCO2 SNPW80X, BCMO1 SNP4, RDHE2 SNP2, ALDH8A1 SNP16 and PPARCG1A SNP12, which were considered as the crucial genes in the signaling pathways involved in the metabolic process of β-carotene. The non-targeted metabolomics analysis of the fat samples were performed by liquid chromatography-mass spectrometry （LC-MS） technology to identify the differential metabolites in different colored fat samples, and the differential metabolites were subsequently subjected to metabolic pathway enrichment analysis. [Result] The 72 subcutaneous fat tissue samples were predominantly white colored, with yellow colored ones （scoring 3 or above） accounting for 30.55%. The SNPs in BCO2, BCMO1, RDHE2 and PPARCG1A genes were observed in different samples, while these SNPs had no significant （P>0.05） correlation with fat color. Compared with the white colored fat samples, a total of 235 differential metabolites were identified in the yellow colored fat samples, which were enriched in the signaling pathways such as unsaturated fatty acid biosynthesis, primary bile acid biosynthesis, and bile secretion. [Conclusion] Comparing the yellow and white colored fat samples collected from the local cattle in Hulun Buir City, there were multiple differential metabolites involving in the signaling pathways closely related to fat formation, in vivo β-carotene transport and trans-membrane transport of β-carotene. In addition, they also directly or indirectly correlated with the β-carotene metabolism associated genes such as BCO2, BCMO1 and PPARCG1A. Further research may focus on the relevant molecular regulatory mechanisms, so as to provide a theoretical basis for the preparation of β-carotene containing feed and the targeted regulation of beef fat color.

[Objective] The aim of the present study was to screen the important signaling pathways and genes involved in carbon tetrachloride （CCl₄） induced intestinal injury in mice and in the treatment process with a traditional Mongolian medicine Honghua Qinggan 13 Flavor Pills. [Method] A total of 18 male C57BL/6 mice aged 6-8 weeks and weighing 20-22 g were randomly divided into three groups, a blank control group （n=6）, a model group （n=6）, and a treatment group （n=6）. The blank control group and model group were gavaged with physiological saline once a day at a dose of 10 mL/（kg·BW） for 7 consecutive days. The treatment group was gavaged with Honghua Qinggan 13 Flavor Pills once a day at a dose of 616.5 mg/（kg·BW） for 14 consecutive days. Four hours after the last gavage, the blank control group was intraperitoneally injected with olive oil, while both the model group and treatment group were intraperitoneally injected with CCl₄ and olive oil mixture （CCl₄∶olive oil=1∶4, V/V） at a dose of 10 mL/（kg·BW）. On the second day following the intestinal injury treatment, the duodenal tissues of the mice in the three groups were collected for high-throughput transcriptome sequencing. Using the obtained sequencing data, the differentially expressed genes were predicted, functionally analyzed, as well as KEGG signaling pathway enriched. The gene groups enriched in the significantly down regulated signaling pathway after the treatment with Honghua Qinggan 13 Flavor Pills were screened, and interaction analysis was performed with the target genes of Honghua Qinggan 13 Flavor Pills. [Result] ① Transcriptome sequencing analysis showed that compared with the blank control group, the model group and the treatment group obtained 1 419 and 2 875 differentially expressed genes, respectively. Compared with the model group, the treatment group obtained 2 288 differentially expressed genes, of which 1 139 were up regulated and 1 149 were down regulated. KEGG signaling pathways enrichment on the differentially expressed genes in the model group found that the activated signaling pathways included osteoclast differentiation, B cells, chemokines, inflammatory bowel disease, JAK-STAT, etc. KEGG signaling pathways enrichment on the differentially expressed genes in the treatment group found that the activated signaling pathways included FOXO, mTOR, longevity regulation, etc, while the inhibited signaling pathways included osteoclast differentiation, cell apoptosis, tumor necrosis factor, B cells, rectal and colorectal carcinoma, etc. ②Four genes with significantly different expression levels, JUN, STAT1, NFKBIA and FOS, were found in the transcriptome data via the gene groups enrichment in the significantly inhibited signaling pathway in the treatment group and interaction analysis between the target genes of Honghua Qinggan 13 Flavor Pills. [Conclusion] The main signaling pathways involved in CCl₄ induced intestinal injury in mice and the treatment process of Honghua Qinggan 13 Flavor Pills included chemokines, inflammatory bowel disease, JAK-STAT and longevity regulation, and the main genes included JUN, STAT1, NFKBIA and FOS. Our results provided references for clarifying the molecular mechanisms of prevention and treatment of intestinal injury with Honghua Qinggan 13 Flavor Pills.

[Objective] This study aimed to assess the effects of gossypol on growth performance, serum antioxidant capacity, and renal pathological morphology of male broilers at different growth stages, so as to accumulate basic experimental data for the rational application of cotton seed meal in broiler breeding. [Method] A total of 48 healthy 1-day-old Liangfenghua male broilers from the same batch were selected and randomly allocated to 4 groups according to the principle of similar body weight, including a control group （C）, a low-dose group （L）, a medium-dose group （M）, and a high-dose group （H）. Each group had 4 replicates, with 3 broilers per replicate. The experimental broilers in different groups fed the same basal diet. In addition, the broilers in L, M and H group were orally administered 100, 150 and 200 mg/（kg·BW） gossypol once a day until 20-day-old, for a total of 20 days, respectively, while those in C group were orally given distilled water. During the experiment, the feed intake and weight gain of the broilers in each group were recorded, and the feed to weight gain ratio at different growth stages were calculated. Blood samples were collected at 6, 11, 16 and 21 days of age, and the serum activities of catalase （CAT） and glutathione peroxidase （GSH-Px） were measured. Kidney tissue samples were collected at 21 days of age, with HE staining sections prepared, and changes in renal histopathology observed. [Result] At 1-15 days of age, the feed to weight gain ratios of L, M and H groups were extremely significantly （P<0.01） higher than that of C group; at 6-15 days of age, the feed to weight gain ratio of M group was extremely significantly （P<0.01） higher than that of L group; at 16-20 days of age, the feed to weight gain ratios of L and H groups were extremely significantly （P<0.01） higher than that of C group, while that of M group had negative increase. At 6-21 days of age, the serum activities of CAT and GSH-Px in C group showed upward trends, while those in L, M and H groups all showed downward trends; at 11 days of age, the serum activities of CAT and GSH-Px in L group were significantly （P<0.05） lower than those in C group, while the serum activity of GSH-Px in M and H groups was extremely significantly （P<0.01） lower than that in C group; at 16 and 21 days of age, the serum activities of CAT and GSH-Px in L, M and H groups were all extremely significantly （P<0.01） lower than those in C group; at 21 days of age, the serum activity of GSH-Px in M group was extremely significantly （P<0.01） lower than that in L group. Pathological histology observations showed that the renal glomeruli of the broilers given gossypol by gavage were swollen, the renal capsule space became narrower, and the renal tubules were necrotic.The degree of renal tissue damage was M group>H group>L group. [Conclusion] Starting from 1-day-old, feeding male broilers with doses of 100, 150 and 200 mg/（kg·BW） of gossypol for 20 consecutive days by gavage reduced growth performance, decreased serum antioxidant capacity, and caused kidney damage. With the prolongation of gossypol feeding time, the above affects were the most obvious at the dose of 150 mg/（kg·BW）.

[Objective] The aims of the present study were to isolate and screen cellulolytic bacteria derived from spent Flammulina velutipes substrate, to assess their biological characteristics and cellulolytic enzyme activities, so as to provide technical supports for the feed utilization of spent mushroom substrate resources. [Method] Spent Flammulina velutipes substrate samples were inoculated using plate dilution coating method. The cellulolytic bacteria were then isolated and cultured on nitrate cellulose sodium medium. The cellulolytic abilities of the isolated strains were preliminarily analyzed using Congo red medium. Candidate strains were selected through 16S rDNA sequencing analysis and biosafety prediction, followed by physiological and biochemical characteristics analysis, growth curve determination at different temperatures, and dynamic analysis of cellulolytic enzyme activities. [Result] A total of 30 independent colonies were isolated after screening culture with nitrate cellulose sodium medium. All of the strains formed clear transparent circles on Congo red medium, and some strains had strong cellulolytic abilities. The 16S rDNA sequencing analysis showed that the 30 isolated strains were identified as belonging to 9 bacterial species, including Pseudomonas koreensis, Advenella mimigardefordensis, Serratia rubidaea, and so on. Taking into account both biosafety prediction and the preliminary cellulolytic abilities screening results, Pseudomonas koreensis （JK-32）, Adrenella mimigardefordensis （JK-52）, Serratia rubidaea （JK-56）, Staphylococcus equiorum （JK-57）, Staphylococcus saprophytics （JK-62） and Serratia marcescens （JK-66） were selected as candidate strains for subsequent experiments. Physiological and biochemical characteristics analysis showed that all of the 6 candidate strains were determined as positive for contact enzyme activity test, and negative for methyl red test and diacetyl test. The growth of JK-62 strain was less affected by temperature, and the growth rate and final bacterial concentration performed better among all the candidate strains. Under the low cultivation temperatures （28-34 ℃）, the growth rate and final bacterial concentration of JK-56 strain were lower than the other candidate strains, while when the cultivation temperature increased to 40 ℃, its growth rate was similar to that of the other candidate strains and the final bacterial concentration was higher. On the 1^st to 7^th days of cultivation, the endoglucanase activity of JK-56 strain was the highest among all the candidate strains. On the 2^nd, 4^th, and 5^th days of cultivation, the endoglucanase activity of JK-66 strain was significantly （P<0.05） higher than that of the CK. The exoglucanase activity of JK-66 strain was higher among the candidate strains and was significantly （P<0.05） higher than that of the CK at different detection time points. On the 2^nd to 4^th days of cultivation, the exoglucanase activity of JK-56 strain was significantly （P<0.05） higher than that of the CK. The β-glucosidase activity of JK-66 strain was higher among the candidate strains. On the 3^rd to 7^th days of cultivation, the β-glucosidase activity of JK-56 strain was next to JK-62 and JK-66 strains among the candidate strains. On the 2^nd to 5^th days of cultivation, the filter paper enzyme activity of JK-56 strain was the highest among the candidate strains. On the 5^th day of cultivation, it was significantly （P<0.05） higher than that of the CK. During this period, the filter paper enzyme activity of JK-66 strain was also at a high level. [Conclusion] Serratia rubidaea JK-56 and Serratia marcescens JK-66 strains had high overall levels of cellulolytic enzyme activities, and prominent endoglucanase and exoglucanase activities, which could be used in combination with strains exhibiting strong β-glucosidase activity for the development and utilization of spent Flammulina velutipes substrate.

[Objective] The aim of this study was to optimize the ultrasonic extraction process parameters of crude fat in feed. [Method] Using the grass carp expanded compound feed as experimental material, a single factor experiment design was adopted to investigate and analyze the effects of 4 factors （liquid to material ratio, soaking time, ultrasonic duration and ultrasonic frequency） at different levels on the determination of crude fat content in feed. In addition to the single factor experiments, a 4-factor and 3-level L9 （3⁴） orthogonal experiment was conducted to optimize the ultrasonic extraction process parameters of crude fat in feed. The crude fat content of grass carp expanded compound feed was measured using the optimized ultrasonic extraction process, and the results were compared to those obtained using the Soxhlet extraction method. The process was repeated 6 times to verify the optimal ultrasonic extraction process parameters. Following the determination of the ultrasonic extraction process parameters, the crude fat contents of 13 different feed samples were measured using both the ultrasonic extraction method and the Soxhlet extraction method with 6 repeated tests. The differences in crude fat content of the feed raw materials and common animal feed products between the two extraction methods were then analyzed and compared. [Result] The factors affecting the determination of crude fat content in feed was in the order of ultrasonic frequency>liquid to material ratio>ultrasonic duration>soaking time. The optimal ultrasonic extraction process parameters were liquid to material ratio of 37.5 mL/g, soaking for 0 min, ultrasonic duration for 30 min, and ultrasonic extraction twice. The crude fat content of grass carp expanded compound feed determined by the optimal ultrasonic extraction process was 4.76% （n=6）, whereas that determined by the Soxhlet extraction method was 4.77% （n=6）, proving that the ultrasonic extraction process was stable and feasible. The differences in crude fat content determination results of 13 different feed samples between the ultrasonic extraction method and the Soxhlet extraction method were not significant （P>0.05）. [Conclusion] The optimal process parameters for ultrasonic extraction of crude fat in feed determined in this study were stable and feasible.

[Objective] The aim of the present study was to screen the soybean varieties suitable for silage maize-forage soybean intercropping model in the low plain areas of eastern Hebei Province. [Method] A total of 35 soybean varieties were selected as experimental materials. Each variety was planted in a 35 m²（5 m×7 m）plot, with 10 cm plant spacing and 40 cm row spacing, and planting density of 170 000 plants/hm². The plots were randomly distributed and repeated three times. The time for flowering, pod setting and grain filling stages of all the soybean varieties was recorded and their growth periods （the number of days from sowing to grain filling stage） were calculated. The soybean were harvested at grain filling stage with fresh weight yield measured. Five soybean plants were randomly selected from each plot and variety, with contents of crude protein （CP）, acidic detergent fiber （ADF）, neutral detergent fiber （NDF）, crude ash （Ash） and crude fat （CF） measured after deactivation, drying and crushing. The entropy weight TOPSIS comprehensive evaluation function in SPSSAU software was used to comprehensively evaluate and rank the feeding quality of all the soybean varieties, and a comprehensive analysis chart for the comprehensive evaluation and ranking of the growth period, fresh weight yield and feeding quality of various soybean varieties was created. [Result] Ruidou No.1 had the longest growth period of 100 days. The growth periods of You 6019, Jindou 99 and Andou 109 reached 97 days, and that of Pudou 5110 was 95 days. The growth periods of Zhonghuang 78, Beidou 17, Beidou 30, Fengdou No.3 and Lindou No.10 were the shortest, only 85 days. Suike 23 （40.48 t/hm²）, Suike 9 （38.34 t/hm²） and Hedou 12 （38.06 t/hm²） were the three varieties with the highest fresh weight yield. Sudou 16 （10.29%） had the highest crude ash content, followed by Jindou 99 （9.80%）, Suike 9 （9.76%） and Shengdi No. 1 (9.57%). The crude protein contents of Wandou 37 （29.17%） and Jiakedou No.1 （25.38%） were significantly （P<0.05） higher than the other varieties. The crude fat contents of Andou 109 （6.33%）, Fengdou No.3 （5.93%） and Wandou 15 （4.97%） were significantly （P<0.05） higher than the other varieties. The ADF contents of Fengdou No.3 （24.05%）, Lindou 10 （24.38%） and Wandou 37 （24.46%） were significantly （P<0.05） lower than the other varieties. The NDF contents of Suike 12 （31.52%）, Jindou 99 （32.82%） and Pudou 5110 （33.39%） were significantly （P<0.05） lower than the other varieties. The top five soybean varieties in the comprehensive evaluation of feeding quality were Jindou 99, Pudou 5110, Andou 109, Suike 12 and Wandou 37. The comprehensive analysis chart based on the overall evaluation and ranking of the growth period, fresh weight yield and feeding quality of different soybean varieties showed that four soybean varieties, Ruidou No.1, Andou 109, Pudou 5110 and Jindou 99, performed well in all the three aspects. [Conclusion] Ruidou No.1, Andou 109, Jindou 99 and Pudou 5110 could be used as candidate varieties for silage maize-forage soybean intercropping model in the low plain areas of eastern Hebei Province.

Cymbopogon citratus contains a variety of bioactive components such as terpenes, aldehydes, alcohols, flavonoids and polyphenols, exerting the bioactive functions of bacteriostasis, antivirus, immune regulation, anti-inflammation, antioxidation, regulation of intestinal health and so on. It also has significant improvement effects on the growth performance, antioxidant stress capacity, anti-parasitic ability and product quality of livestock and poultry. This article reviews the nutritional value, bioactive function and application of Cymbopogon citratus in livestock and poultry production, in hoping to provide references for the development and promotion of Cymbopogon citratus.

[Objective] This study was conducted to characterize the expression pattern of antioxidant enzymes in sheep antral ovarian follicles with different diameters, so as to provide references for clarifying the regulatory mechanism of antioxidant function in ovarian follicles. [Method] The follicular fluids were sampled from sheep antral ovarian follicles with different diameters （large antra ≥ 6.0 mm, medium antra 2.0-6.0 mm, small antra ≤ 2.0 mm). The contents of reactive oxygen species （ROS） and total antioxidant capacity （TAC）, as well as the activities of superoxide dismutase （SOD）, catalase （CAT）, glutathione peroxidase （GPX） and peroxidase （PRDX） were tested using the commercially available reagent kits. Real time fluorescence quantitative PCR （qPCR） assay was used to detect the relative mRNA expression levels of Cu/Zn-SOD, CAT, GPX3 and PRDX6 genes in the theca cells, mural granulosa cells and cumulus cells of small, medium and large antral ovarian follicles. [Result] There were no significant （P>0.05） differences in the contents of TAC and ROS in the follicular fluids of antral ovarian follicles with different diameters. The activities of SOD, GPX and PRDX in the follicular fluids decreased with the increase of ovarian follicle diameters. The small antral ovarian follicles had extremely significantly （P<0.01） higher activities of SOD, GPX and PRDX in the follicular fluids compared to the large antral ovarian follicles. The CAT activity in the follicular fluids elevated with the increase of ovarian follicle diameters. The large and medium antral ovarian follicles had extremely significantly （P<0.01） higher CAT activities in the follicular fluids than the small antral ovarian follicles. The relative mRNA expression levels of Cu/Zn-SOD, GPX3 and PRDX6 genes in the theca cells and mural granulosa cells of the small antral ovarian follicles were extremely significantly （P<0.01） higher than those of the medium and large antral ovarian follicles, while the relative mRNA expression levels of Cu/Zn-SOD, GPX3 and PRDX6 genes in the cumulus cells of the medium antral ovarian follicles were extremely significantly （P<0.01） higher than those of the small and large antral ovarian follicles. The large antral ovarian follicles had extremely significantly （P<0.01） higher relative mRNA expression levels of CAT gene in the theca cells and mural granulosa cells than the small and medium antral ovarian follicles, while the large and medium antral ovarian follicles had extremely significantly （P<0.01） higher relative mRNA expression levels of CAT gene in the cumulus cells than the small antral ovarian follicles. [Conclusion] There was no significant variations in contents of TAC and ROS in sheep antral ovarian follicles with different diameters, but the gene expression levels and the activities of antioxidant enzymes of SOD, CAT, GPX and PRDX in ovarian follicles with different diameters exhibited spatial specificity, indicating that the regulation of antioxidant function in sheep antral ovarian follicles was a synergistic process of multiple factors.

Fatty acid binding proteins （FABPs） are widely present in animal tissues and affect cell differentiation by regulating the transport and metabolism of intracellular fatty acid. They also play a crucial role in inflammation regulation and immune metabolism in the body. Unveiling the association between the FABPs gene family and animal phenotype is of great significance for improving the individual economic value of livestock and poultry. This article introduces the main functions of the FABPs gene family members and their distribution in animal tissues and organs, reviews the research progress of representative members of the gene family, H-FABP gene and A-FABP gene, in the field of livestock and poultry breeding, in hoping to provide references for using this gene family to conduct molecular marker assisted breeding and to improve livestock and poultry production traits.

The low reproductive rate is a bottleneck that restricts the development of the equine animal industry, and the inadequate technology for reproductive regulation is the primary cause for the slow growth of the industry. Gonadotropin-releasing hormone （GnRH）, a neurohormone released by the hypothalamus, plays essential roles in the hypothalamic-pituitary-gonadal-axis pathway. GnRH can effectively promote follicular development and ovulation in equine animals. It is a decapeptide-containing compound that can be synthesized into many GnRH analogues by varying the amino acids at different locations within the decapeptide structure. GnRH and its analogues affect animal reproductive performance by stimulating the secretion of follicle-stimulating hormone （FSH） and luteinizing hormone （LH）, and inhibiting the synthesis of estrogen receptors. It has been demonstrated that GnRH and its analogues could improve the reproductive performance of equine animals. This article reviews the structural characteristics and biological functions of GnRH and gonadotropin-releasing hormone receptor （GnRHR） as well as the research progress in the application of GnRH analogues in the reproduction of equine animals, in hoping to provide references for exploring the molecular mechanisms behind the biological effects of GnRH and the scientific application of GnRH analogues in the reproductive regulation of equine animals.

[Objective] The present study was conducted to assess the correlations between serum hormone levels and lactation performance in Alagxa Bactrian camels. [Method] A total of 65 Alagxa Bactrian camels with similar body conditions and parities in the early lactation stage were selected, and their serum hormone levels （estradiol, estriol, estrone, follicle-stimulating hormone, luteinizing hormone, progesterone, prolactin, growth hormone, cortisol, 5-hydroxytryptamine, epinephrine, norepinephrine, insulin, glucagon, leptin） as well as the lactation performance indicators （milk yield, milk protein rate, milk fat rate, lactose rate, ash content） were determined. Canonical correlation analysis between serum hormone levels and lactation performance was carried out: using lactation performance indicators as the X group variables, with V being the corresponding comprehensive variable; using serum hormone levels as the Y group variables, with W being the corresponding comprehensive variable; the overall correlation between the two groups of indicators were reflected by the correlation between the two comprehensive variables, and the correlations between serum hormone levels and various indicators of lactation performance were explored. [Result] In the X group of lactation performance indicators, the variation degree in the milk yield was the highest, followed by milk fat rate, while the coefficients of variation in lactose rate, ash content and milk protein rate were relatively small. In the Y group of serum hormone level indicators, progesterone had the highest coefficient of variation, followed by estradiol, luteinizing hormone, norepinephrine, follicle-stimulating hormone, 5-hydroxytryptamine, cortisol, estrone, prolactin, epinephrine, insulin, estriol, growth hormone, leptin and glucagon. The correlation analysis among the internal variables of serum hormone levels showed that serum levels of estriol were significantly positively correlated with those of estrone （r=0.88, P<0.001）, luteinizing hormone （r=0.70, P<0.001） and prolactin （r=0.59, P<0.001）. The canonical correlation analysis between lactation performance and serum hormone levels indicated strong correlation between milk protein rate and serum level of estriol. [Conclusion] The milk protein rate in the early lactation stage of Alagxa Bactrian camels is correlated with serum hormone levels of estriol, estrone, luteinizing hormone and prolactin.

[Objective] This study aimed to assess the effects of parity, body condition score and backfat thickness on reproductive performance of sows in late pregnancy. [Method] A total of 654 Dannish sows in late pregnancy （109 d of gestation） were selected from the same production batch, and were grouped according to the parity （1-3 parity groups）, body condition score （1-5 score groups）, and backfat thickness （≤ 10 mm group, 11-15 mm group, 16-20 mm group, 21-25 mm group, and > 25 mm group）. The first parity group, body condition score 3 group, and backfat thickness 16-20 mm group were used as the control groups, and the other groups within the same indexes were used as the experimental groups. The data of body condition score, backfat thickness and parity as well as total number of piglets born, live litter weight, number of live piglets, number of healthy piglets, number of weak piglets, number of mummified fetus, and number of stillborn piglets were all entered and processed by the linear mixed model of IBM SPSS Statistics 26.0 statistical software. [Result] With the increased parities of the pregnant sows, the total number of piglets born, live litter weight, number of live piglets, and number of healthy piglets exhibited a significantly （P<0.05） increasing trend. When the backfat thickness of the sows in late pregnancy was in the range of 16-20 mm, the total number of piglets born, number of live piglets, and number of healthy piglets reached the maximum values, while the number of weak piglets and number of stillborn piglets reached the minimum values. When the backfat thickness of the sows in late pregnancy was in the range of 21-25 mm, the number of weak piglets, number of mummified fetus, and number of stillborn piglets were all elevated. When the body condition score of the sows in late pregnancy was 4, the total number of piglets born, number of live piglets, and number of healthy piglets were the highest. [Conclusion] Parity, body condition score and backfat thickness of sows in late pregnancy all have impacts on litter performance and can serve as important references for predicting sow reproductive performance.

[Objective] This study was conducted to characterize the microbial community diversities in pig house environments, to understand the structural differences of bacterial communities in different types of pig house environments, and to identify the potentially pathogenic bacterial genera. [Method] Environmental microbial samples were collected from pregnant sow houses, nursery pig houses and farrowing houses in a large-scale pig farm using air sedimentation method. Three houses were sampled for each type of pig house, with a total of 9 samples. Using Illumina Miseq technology, the high-throughput sequencing was performed targeting on the V3-V4 variant region of bacterial 16S rDNA. The sequencing data were analyzed by QIIME2 software to compare the composition of microbial communities in different types of pig house environments. [Result] At the similarity threshold of 97%, a total of 29 126 OTUs were obtained from the 9 samples, covering 31 phyla, 66 classes, 160 orders, 320 families, 899 genera and 1 831 species of bacteria. The Chao1 index, Shannon index and phylogenetic diversity index of the farrowing houses and nursery pig houses were generally higher than those of the pregnant sow houses. Proteobacteria, Bacteroidota, Firmicutes and Actinobacteriota were the four dominant bacterial groups at the phylum level in the pig house environments. The relative abundance of Proteobacteria was the highest in all three types of pig houses, while the relative abundance of Firmicutes, Actinobacteria and Bacteroidetes varied greatly among different types of pig houses. Acinetobacter, Corynebacterium and Stenotrophomonas were the genera with the highest relative abundance in farrowing houses, pregnant sow houses and nursery pig houses, respectively. There were multiple genera of bacteria with potential pathogenicity to animals, such as Helcococcus, Streptococcus, Legionella and Serratia, in the air of pig houses. [Conclusion] The pig house environments were rich in microbial community diversities. Farrowing houses and nursery pig houses had higher bacterial diversity, evolutionary diversity and abundance than the pregnant sow houses. The potentially pathogenic bacteria found in this study provided references for the selection of disinfection drugs used in pig house environments.

[Objective] This study was conducted to screen the high-yield and good-quality annual forage grass varieties suitable for planting and promoting in the Mu Us Sandy Land. [Method] A total of 12 forage grass varieties such as Juncao, forage sweet sorghum and forage maize were used as experimental materials, and their phenophase, agronomic traits and nutritional qualities were observed and measured. The adaptability of the varieties was comprehensively evaluated through variance analysis, correlation analysis and membership function. [Result] All of the 12 tested varieties exhibited adaptability to the local growth environment, completed vegetative growth phase and harvested forage grass. The fresh yield of Giant Juncao （Cenchrus fungigraminus） was the highest, followed by the forage sweet sorghum cultivar Lyujuren. The performance of the tested varieties in the hay yield was similar to that in the fresh yield. Giant Juncao had the highest crude protein yield, followed by the Juncao cultivar Lyuzhou No.1. Among the primary traits of the 12 introduced forage grass varieties, the plant height was extremely significantly （P<0.01） positively correlated with the fresh and hay yields, and the plant height and hay yield were significantly （P<0.05） negatively correlated with the crude protein content and relative feed value. The varieties with top three scores in membership function analysis from high to low were Giant Juncao, annual Melilotus officinalis, and Sorghum Hybrid Sudangrass cultivar Julang. [Conclusion] Comprehensive evaluation and analysis demonstrated that among the 12 tested forage grass varieties, the adaptability of Giant Juncao, annual Melilotus officinalis and Sorghum Hybrid Sudangrass cultivar Julang was better. The research results provided references for introducing suitable forage grass varieties in the Mu Us Sandy Land.

[Objective] This study was conducted to understand the prevalence of virulence and antimicrobial resistance genes in Escherichia coli （E. coli） strains derived from diarrheal lambs in large-scale sheep farms in Hotan Prefecture, Xinjiang Uygur Autonomous Region, China. [Method] A total of 70 anal swabs of diarrheal lambs were sampled from 3 large-scale sheep farms in Hotan Prefecture. Traditional methods such as bacterial isolation and culture, staining and microscopy, biochemical identification, and 16S rDNA PCR amplification and sequencing were used to isolate and identify E. coli strains in the samples. PCR assay was employed for phylogenetic grouping of E. coli strains, as well as detection of virulence and antimicrobial resistance genes. [Result] Through morphological observation, biochemical identification, and 16S rDNA sequence analysis, a total of 38 strains of E. coli were isolated and identified from the 70 anal swabs of diarrheal lambs, with a separation rate of 54.3% （38/70）. Phylogenetic grouping analysis showed that B1 group was the dominant group （68.4%, 26/38） of the isolated strains, followed by A group （26.3%, 10/38） and D group （5.3%, 2/38）, and B2 group was not detected. The results of virulence gene testing showed that 4 out of 8 E. coli virulence genes were detected, and the proportion of fimC gene carrying strains were the highest at 92.1% （35/38）, followed by irp2 gene at 47.4% （18/38）, hlyF gene at 36.8% （14/38）, and fyuA gene at 34.2% （13/38）; the genes of eaeA, ST, LT and Stx1 were not detected. The results of antimicrobial resistance gene testing showed that 6 out of 8 E. coli resistance genes were detected, with the carrying rate of sulfonamide resistance gene sul2 being the highest at 42.1% （16/38）; no aminoglycoside resistance genes were detected. [Conclusion] The E. coli strains from diarrheal lambs in Hotan Prefecture harbor virulence and antimicrobial resistance genes. The prevalence of pathogenic E. coli of sheep origin in this region should be monitored.

The long-term and widespread use of antibiotics in the animal husbandry industry has led to serious problems such as drug residues and antibiotic resistance, which seriously threatens the health of animals and even humans. Bacteriophages are viruses that can invade and lyse bacteria, with the advantages of strong specificity, wide presence, and low research and development cost. With the continuous development of science and technology, the research of bacteriophages in the livestock and poultry industry has been deepened, and the use of bacteriophages is progressively gaining recognition as an alternative strategy to antibiotics. Starting from the biological characteristics of bacteriophages, this article elaborates on the research of bacteriophages therapy for bacterial infections in livestock and poultry as well as the development and application of bacteriophages in livestock and poultry breeding, food biological control, etc., in hoping to provide references for the application of bacteriophages in livestock and poultry production.