Animal Bioscience最新文献

Objective: Lactic acid (LA) treatment of cereals is known to improve ruminant performance. However, changes in cereal nutrient levels and variations in rumen fermentation remain unclear.

Methods: This study was designed to compare the effects of 5% LA treatment on the trophic and morphological characteristics of barley and to discover the differences in rumen fermentation characteristics and metabolomes between LA-treated and untreated barley.

Results: Compared with those of untreated barley (BA), the dry matter (DM), crude protein (CP), ash and water-soluble carbohydrate contents of barley plants treated with 5% LA for 48 h (BALA) decreased, but the resistant starch (RS) and non-fiber carbohydrate contents increased. Moreover, the amount of proteinaceous matrix in BA decreased in response to LA treatment. During in vitro fermentation, BALA had a greater pH but lower dry matter disappearance and ammonia, methane, and short-chain fatty acid levels than BA. The differential metabolites between BA and BALA were clustered into metabolic pathways such as purine metabolism, lysine degradation, and linoleic acid metabolism. Observable differences in ultrastructure between BALA and BA were noted during fermentation.

Conclusion: Lactic treatment altered barley nutrient content, including DM, CP, RS, ash, water-soluble carbohydrates and non-fiber carbohydrates, and affected barley ultrastructure. These variations led to significant and incubation time-dependent changes in the in vitro fermentation characteristics and metabolome.

Objective: This study aimed to determine the effects of compatibility of Clostridium butyricum and Bacillus subtilis on growth performance, lipid metabolism, antioxidant status and cecal microflora of broilers during the starter phase.

Methods: A total of 600 1-day-old Ross 308 broilers were randomly divided into two groups with six replicates in each group. Chickens in the control group were fed a basal diet, while chickens in the experimental group were fed a diet supplemented with 2×108 colony forming units (CFU)/kg of C. butyricum and 1×109 CFU/kg of B. subtilis. The experimental period was 21 days.

Results: Addition of C. butyricum and B. subtilis significantly increased (p<0.05) the body weight and liver nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME) activity of broilers, enhanced (p<0.05) the average daily gain and average daily feed intake of broilers. However, the addition of C. butyricum and B. subtilis did not significantly affect the concentrations of triglyceride and total cholesterol in the serum, the activities of fatty acid synthase and acetyl-CoA carboxylase in the liver, the total antioxidant capacity, glutathione peroxidase activity and malondialdehyde content in the serum and liver. Besides, microbial analysis revealed that supplementation of C. butyricum and B. subtilis increased (p<0.05) the abundance of Firmicutes such as CHKCI001 and Faecalibacterium, decreased (p<0.05) the abundance of Bacteroidota such as Bacteroides and Alistipes. Spearman correlation analysis confirmed that the above cecal microbiota were closely related to the growth performance of broilers (p<0.05). In addition, simultaneous supplementation of C. butyricum and B. subtilis significant affected (p<0.05) 33 different functional pathways such as lipid metabolism and carbohydrate metabolism. This explains the phenomenon of increased growth performance and liver NADP-ME activity in the probiotics group.

Conclusion: The compatibility of C. butyricum and B. subtilis could improve the growth of broilers during the starter phase by changing the cecal microflora.

Objective: This study was conducted to evaluate the effects of organic and inorganic selenium mixes in pregnant sows on piglet growth, selenium levels in serum and milk, and selenium deposition in newborn piglet tissues.

Methods: A total of 44 multiparous sows (Yorkshire×Landrace) with average body weight (BW), backfat thickness, and parity were assigned to one of the three treatments with 14 or 15 sows per treatment in a completely randomized design. The treatments were as follows: i) Control, corn-soybean meal-based diet with no addition of selenium premix; ii) ISOS (mixed inorganic selenium and organic selenium) 30, a basal diet supplemented with 0.15 ppm of inorganic Se and 0.15 ppm of organic Se; iii) ISOS50, a basal diet supplemented with 0.25 ppm of inorganic Se and 0.25 ppm of organic Se.

Results: At day 21 of lactation, supplementing a high level of mixed Se at 0.50 ppm resulted in higher piglet BW and weight gain than adding a low level of mixed Se at 0.30 ppm (p<0.05). Selenium concentration of colostrum in sows fed ISOS50 diet was significantly higher than those in sows fed ISOS30 diet (p<0.05). Selenium concentrations in the serum at days 90 and 110 of gestation and 24 hours postpartum were highest when sows were fed ISOS50 diet (p<0.05). Additionally, increasing levels of mixed Se led to an increase in piglet serum Se concentration at 24 hours postpartum (p<0.05). Before ingesting colostrum, piglets from sows fed a mixed selenium (Se) diet had significantly higher kidney Se concentrations compared to those from the control group, with the ISOS50 treatment showing the most significant difference (p<0.05).

Conclusion: Supplementation of the gestation diet with 0.5 ppm of mixed Se may improve piglet growth performance, increase Se concentrations in milk, and enhance Se status in the serum of sows, as well as in the serum and tissues of their offspring.

Objective: The effects of carnosine synthesis on the structural and microstructural determinants of meat quality have not been studied to date. Therefore, this study aimed to investigate the effect of supplementation with carnosine synthesis precursors on the characteristics and microstructure of breast muscle fibers in slow-growing Korat chickens (KR).

Methods: Slow-growing KR were fed a non-supplemented commercial diet (control group) or a commercial diet supplemented with 1.0% β-alanine, 0.5% L-histidine, or a combination of both 1.0% β-alanine and 0.5% L-histidine. At 10 weeks, KR were slaughtered, and the breast muscle was collected. Samples were fixed and extracted to study the microstructure, fat level, and porosity of the meat using X-ray and scanning electron microscopy, and real-time polymerase chain reaction was performed to analyze the expression of genes related to myofiber differentiation.

Results: L-histidine supplementation significantly altered myofiber diameter and muscle fiber density and compactness by regulating muscle fiber-type differentiation via carnosine synthase (CARNS1) and myocyte enhancer factor 2C expression, as well as myogenic differentiation antigen and myogenic regulatory factor 5 expression. While excess L-histidine potentially stimulated CARNS1 to modify muscle fiber arrangement and tenderness in breast meat, dietary β-alanine supplementation alone or in combination with L-histidine supplementation induced a relatively less remarkable but not significant (p<0.05) effect on the breast meat characteristics studied.

Conclusion: Interestingly, the combination of β-alanine and L-histidine supplementation had no effect on meat microstructure, meat porosity, and fat content in comparison with the control group. Thus, this combination had the best selectivity for improving meat quality. However, further studies are required to clarify the effects of carnosine levels on meat processing.

Objective: Asparagine synthetase (ASNS) is an aminotransferase responsible for the biosynthesis of aspartate by using aspartic acid and glutamine. ASNS is highly expressed in fast-growing broilers, but few studies have reported the regulatory role of ASNS in muscle development.

Methods: To explore the function of ASNS in chicken muscle development, the expression of ASNS in different chicken breeds and tissues were first performed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Then, using real-time quantitative RT-PCR, western blot, EdU assay, cell cycle assay and immunofluorescence, the effects of ASNS on the proliferation and differentiation of chicken skeletal muscle satellite cell (SMSC) were investigated. Finally, potential mechanisms by which ASNS influences chicken muscle fiber differentiation were identified through RNA-Seq.

Results: The mRNA expression pattern of ASNS in muscles mirrors trends in muscle fiber cross-sectional area, average daily weight gain, and muscle weight across different breeds. ASNS knockdown inhibited SMSC proliferation, while overexpression showed the opposite. Moreover, ASNS attenuated SMSC differentiation by activating the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway. Additionally, 5-aminoimidazole4-carboxamide1-β-D-ribofuranoside (AICAR) treatment suppressed the cell differentiation induced by siRNA-ASNS. RNA-Seq identified 1,968 differentially expressed genes (DEGs) during chicken SMSC differentiation when overexpression ASNS. Gene ontology (GO) enrichment analysis revealed that these DEGs primarily participated in 8 biological processes, 8 cellular components, and 4 molecular functions. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis identified several significantly enriched signaling pathways, such as the JAK-STAT signaling pathway, tumor necrosis factor signaling pathway, toll-like receptor signaling pathway, and PI3K-Akt signaling pathway.

Conclusion: ASNS promotes proliferation while inhibits the differentiation of chicken SMSCs. This study provides a theoretical basis for studying the role of ASNS in muscle development.

Objective: This research aimed to analyze the prevalence, molecular characteristics, toxinotyping, alpha toxin production potential, and antibiotic resistance pattern of Clostridium perfringens (C. perfringens) isolates in meat samples collected from various sources.

Methods: Sixty meat samples were screened for alpha toxin using enzyme-linked immunosorbent assay, revealing a positivity rate of 13.3%, predominantly in raw poultry meat. Subsequent culturing on Perfringens agar identified nine samples harboring characteristic C. perfringens colonies, primarily isolated from raw poultry meat. Molecular confirmation through 16S rRNA gene amplification and sequencing authenticated twelve isolates as C. perfringens, with nine strains exhibiting genetic resemblance to locally isolated strains. Toxinotyping assays targeting alpha toxin-specific genes confirmed all nine isolates as type A C. perfringens, with no detection of beta or epsilon toxin genes. Hemolytic assays demonstrated varying alpha toxin production potentials among isolates, with accession number OQ721004.1 displaying the highest production capacity. Moreover, antibiotic resistance profiling revealed multi-drug resistance patterns among the isolates.

Results: The study identified distinct clusters within C. perfringens strains, indicating variations. Phylogenetic analysis delineated genetic relatedness among strains, elucidating potential evolutionary paths and divergences.

Conclusion: The findings underscore the need for robust surveillance and control measures to mitigate the risk of C. perfringens contamination in meat products, particularly in raw poultry meat. Enhanced monitoring and prudent antimicrobial stewardship practices are warranted in both veterinary and clinical settings to address the observed antibiotic resistance profiles and prevent foodborne outbreaks.

Objective: Somatostatin (SS) plays important regulatory roles in animal growth and reproduction by affecting the synthesis and secretion of growth hormone (GH). However, the mechanism by which SS regulates growth and development in goats is still unclear.

Methods: In this study, we randomly selected eight 7-month-old Dazu black goats (DBGs) of similar body weight and equally assigned four bucks as the immunised and negative control groups. The immunised group received the Salmonella typhi attenuated vaccine X9241 (ptCS/2SS-asd) orally, whilst the negative control group received the empty vector vaccine X9241 (pVAX-asd) orally.

Results: The SS concentration in the serum of goats in the immunised group was significantly lower than that in the negative control group, and the daily gain was significantly higher (p<0.05). SS-14 DNA vaccine immunisation resulted in significantly higher concentrations of growth-related hormones such as GH-releasing hormone and insulin growth factor 1 (IGF-1) in the serum of goats (p<0.05). RNA-seq analysis of hypothalamus of oral SS-14 DNA vaccine and negative control DBGs identified 31 differentially expressed genes (DEGs). Pituitary gland identified 164 DEGs. A total of 246 DEGs were detected in the liver by RNA-seq. Gene ontology of DEGs was enriched in mitochondrial envelope, extracellular region, receptor binding and cell proliferation. The biological metabolic pathways associated with DEGs were explored by Kyoto encyclopedia of genes and genomes analysis. DEGs were associated with metabolic pathways, oxidative phosphorylation, vitamin digestion and absorption and galactose metabolism. These candidate genes (e.g. DGKK, CYTB, DUSP1, and LRAT) may provide references for exploring the molecular mechanisms by which SS promotes growth and development.

Conclusion: Overall, these results demonstrated that the SS DNA vaccine enhanced the growth of DBGs by altering growth-related hormone concentrations and regulating the expression of growth-related genes in the hypothalamic-pituitary-liver axis.

Objective: Recently, the application in the field of germplasm resource conservation has become an important application of primordial germ cells (PGCs). However, due to the lack of deep understanding of the biological characteristics of PGCs at different time points, there is no systematic scheme for the selection of PGCs at which time points in practical application, which affects the practical application effect of PGCs. This study aims to clarify the differences in PGCs during development.

Methods: Here, migration experiment, EdU proliferation assay and cell apoptosis assay were conducted to compare the differences in the migration ability, the proliferation ability and the recovery efficiency among female and male PGCs at E3.5, E4.5, and E5.5, which were explained by the following transcriptome sequencing analysis.

Results: We found that there were larger differences between female and male PGCs at different embryonic ages, while smaller differences between female and male PGCs at the same embryonic age. Further comparison showed that the cell migration ability of female and male PGCs decreased gradually during development, so female and male PGCs at E3.5 are more suitable for in vitro allotransplantation. At the same time, the proliferation ability of PGCs gradually decreased during development, and cell adhesion and extracellular matrix communication were weakened, indicating that female and male PGCs of E3.5 are more suitable for in vitro long-term culture cell line establishment. Interestingly, female and male PGCs at E5.5 showed strong DNA damage repair ability, thus more suitable for in vitro long-term cryopreservation.

Conclusion: This study provides a theoretical basis for systematically selecting PGCs at suitable developmental time points as cell materials for efficient utilization by analyzing the characteristics of female and male PGCs at different developmental time points based on transcriptome.

Objective: Avian influenza virus (AIV) infections first affect the respiratory tract of chickens. The epithelial cells activate the host immune system, which leads to the induction of immune-related genes and the production of antiviral molecules against external environmental pathogens. In this study, we used chicken tracheal epithelial cells (TECs) in vitro model to investigate the immune response of the chicken respiratory tract against avian respiratory virus infections.

Methods: Eighteen-day-old embryonic chicken eggs were used to culture the primary chicken TECs. Reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry (ICC) analysis of epithelial cell-specific gene makers were performed to confirm the characteristics, morphology, and growth pattern of primary cultured chicken TECs. Moreover, to investigate the cellular immune response to AIV infection or polyinosinic-polycytidylic acid (poly [I:C]) treatment, the TECs were infected with the H5N1 virus or poly (I:C). Then, immune responses were validated by RT-qPCR and western blotting.

Results: The TECs exhibited polygonal morphology and formed colony-type cell clusters. The RT-qPCR results showed that H5N1 infection induced a significant expression of antiviral genes in TECs. We found that TECs treated with poly (I:C) and exposed to AIV infection-mediated activation of signaling pathways, leading to the production of antiviral molecules (e.g., pro-inflammatory cytokines and chemokines), were damaged due to the loss of junction proteins. We observed the activation of the nuclear factor kappa B and mitogen-activated protein kinase (MAPK) pathways, which are involved in inflammatory response by modulating the release of pro-inflammatory cytokines and chemokines in TECs treated with poly (I:C) and pathway inhibitors. Furthermore, our findings indicated that poly (I:C) treatment compromises the epithelial cell barrier by affecting junction proteins in the cell membrane.

Conclusion: Our study highlights the utility of in vitro TEC models for unraveling the mechanisms of viral infection and understanding host immune responses in the chicken respiratory tract.