Animal Biotechnology最新文献

The efficacy of microbial fermented feeds (FF) is highly dependent on microbial composition, underscoring the need for locally sourced, cost-effective formulations to advance sustainable livestock production. In this study, bacteria from corn silage (CSB) were screened for the preparation of solid-state fermented feed (SFF). In addition, for the purpose of comparison, purchased marketed fermentation bacteria (PMB) for SFF were also tested using the same methodology. Anaerobic fermentation was carried out by adding 5% CSB, PMB, and saline to conventional feeds at 37 °C, respectively. Then 10 g of fermentation samples was collected on days 0, 3, and 5, respectively. The composition and diversity of the microbial community were subsequently analyzed using high-throughput sequencing. The pH, titratable acidity (TA), and nutrient index of the feeds before and after fermentation were determined. High-throughput sequencing results showed that the dominant genera of CSB were Weissella, Pseudomonas, and Bacteroidetes, whereas the dominant genera of PMB were Bacteroidetes, Bacillus, Pseudomonas, and Enterococcus. The dominant genera in unfermented feeds (CK) were Chlorophyta, Mitochondria, and Pseudomonas. In addition, the dominant genera in SFF supplemented with CSB and PMB were Weissella and Bacteroidetes, respectively. Compared with CK, pH of SFF supplemented with CSB and PMB decreased gradually, and TA increased significantly and then decreased gradually during fermentation. Similarly, Crude fiber content was higher than CK in both CSB and PMB, while crude fat content was lower than CK for all of them. The study illustrates that CSB can be used to ferment porcine solid feeds and that CSB solid feed microorganisms may promote intestinal absorption of complex polysaccharides in pigs, which lays a certain theoretical foundation for the application of CSB to SFF.

This study explored the effects of dietary supplementation with a probiotic blend of Lactococcus lactis subsp. lactis and Bacillus velezensis on the performance and health of growing rabbits. Ninety-six rabbits were allocated into three groups and fed for eight weeks on diets containing either no probiotic (control), a low-dose probiotic (1 ml/kg of each probiotic strain), or a high-dose probiotic (2 ml/kg of each probiotic strain). Probiotic inclusion, particularly at the higher level, significantly enhanced final body weight, feed conversion ratio, and overall performance. Improvements were also noted in carcass characteristics, with greater yields in both forequarters and hindquarters. Blood biochemical analysis revealed elevated antioxidant enzyme activity and immunoglobulin levels, alongside reductions in lipid fractions and better liver and kidney function indicators. Meat quality also benefited, as shown by lower pH, reduced water holding capacity and cooking loss, and more favorable color metrics. Microbial analysis of cecal and feed samples indicated a notable increase in beneficial bacteria and a decline in pathogenic species in the probiotic-treated groups. These findings suggest that combined probiotic supplementation is a promising strategy for enhancing growth performance, meat quality, and gut health in rabbit production systems to produce a good final meat product.

Cold ambient temperatures decrease semen quality. However, the effects of dietary energy sources on semen quality under cold stress conditions remain unclear. In the present study, purebred Yorkshire boars (572 days old) were fed diets supplemented with either fat (FAT), amino acid complex (AA), or dietary fiber beet pulp (BP) during the winter. The experiment was conducted for 84 days. Results showed that BP supplementation increased semen volume, sperm count, plasma immunoglobulin M level and the relative abundance of fecal norank_f_Erysipelotrichaceae (positively correlated with sperm viability), while decreasing the levels of interleukin-1β and lipopolysaccharide-binding protein (p < 0.05). AA supplementation increased sperm density, progressive motility, and sperm velocity during weeks 7-12 (p < 0.05), while no significant effect was observed during weeks 1-6. The relative abundance of fecal Lachnospiraceae_UCG-006 (positively correlated with sperm velocity) also was increased in the AA group. FAT supplementation had a minor effect on sperm progressive motility and average curvilinear velocity, which may be related to the increased relative abundance of fecal T2WK15B57 (negatively correlated with semen quality). In summary, daily supplementation with BP and AA improves sperm quality under cold stress conditions, likely through improvements in inflammation, immunity and intestinal microflora.

The natural flavonoid quercetin, which exhibits a range of biological activities, has been implicated in liver disease resistance in recent research. In vivo study attesting to quercetin's protective effect against metabolic-associated fatty liver disease (MAFLD) is inadequate, however. Here, our investigation explored the potential benefits of quercetin in preventing MAFLD in C57BL/6 mice fed a high-fat diet (HFD). The results revealed that quercetin ameliorated the aberrant enhancement of body and liver weight. The hepatic histological anomalie induced by MAFLD were also mitigated by quercetin. HFD-induced imbalance in serum LDL, HDL, AST, ALT, TG, and LDH was mitigated by quercetin. Mechanically, we found that quercetin improved lipid metabolism by reducing lipogenesis proteins including ACC, FASN, and SREBP-1c and enhancing β-oxidation proteins including PPARα and CPT1A. In vitro study demonstrated that quercetin regulated hepatic lipid metabolism by targeting SREBP-1c and PPARα. Additionally, quercetin enhanced the antioxidant capacity in HFD-treated mice by downregulating Nrf2 and HO-1 expressions and upregulating SOD and GPX1 expressions. The hyper-activation of inflammation was also restored by quercetin via eliminating the phosphorylation of IκBα and NF-κB p65. Collectively, our observations highlight that quercetin exerts hepatoprotective properties in MAFLD mice by regulating hepatic lipid metabolism, oxidative stress and inflammatory response.

Fistulated animals and rumen simulation systems are essential for evaluating the effects of ingredients like probiotics, proposed as sustainable alternatives to growth-promoting antibiotics in ruminant nutrition. This study assessed the impact of microencapsulated probiotics on the structure and functionality of an initial ruminal microbial community using in vivo (IVV) and in vitro (IVT) systems. The IVT system was inoculated with rumen fluid obtained from the cattle animal used as IVV system. Over time, both systems were analysed for short-chain fatty acid (SCFA) production, microbial composition and functionality using next-generation sequencing. Physicochemical parameters were consistent across both systems and the inoculum, with an increase in propionate concentration observed. Although the microbial composition of IVV and IVT systems was highly similar (Pearson correlation of 0.869), significant differences in B-diversity were noted (p value = 0.023). The systems also exhibited high similarity in enzymatic profiles (correlation: 0.971) and metabolic pathways (correlation: 0.938), despite differences in functional B-diversity. Both systems showed increased production of fibrolytic enzymes, enhancing feed efficiency. The use of microencapsulated probiotics induced both taxonomic and functional changes in the initial microbial community of the IVT and IVV systems, which can be linked to the zootechnical effects of using probiotics as additives in ruminal animal nutrition.

Kalmyk cattle are an important meat breed in Kazakhstan, valued for their strong physique, genetic stability, and adaptability. In this study, we investigated the mRNA expression of ELOVL fatty acid elongase 6 (ELOVL6) and CREB-regulated transcription coactivator 2 (CRTC2) across multiple tissues, and further examined their genetic variations and associations with growth and carcass traits in 200 Kalmyk cattle. Expression analysis showed that CRTC2 was most highly expressed in the heart and liver, whereas ELOVL6 was predominantly expressed in the spleen and large intestine, highlighting their tissue-specific expression patterns. In addition, we identified a polymorphic SNP (g.16511290A > G) in the 3'UTR of ELOVL6, with three genotypes (AA, AG, GG) and the G allele being dominant (0.520). Polymorphism information content (PIC) analysis indicated high genetic diversity at this locus. Importantly, this SNP was significantly associated with live weight and body oblique length (p < 0.05), and individuals carrying heterozygous AG genotype showed higher body weight and length. Collectively, these findings suggest that g.16511290A > G within ELOVL6 may serve as useful molecular markers for body measurements and meat traits, providing valuable resources for marker-assisted selection in beef cattle breeding programs.

This study aimed to explore the diversity and functions of rumen mycobiota in 14‑ (PLf) and 15‑rib (DLf) Jiani yaks using ITS sequencing. A total of 1,079,105 and 1,086,799 filtered sequences were obtained for the PLf and DLf groups, respectively, with 491 ASVs common to both. No significant difference regarding the α‑diversity of mycobiota within the two groups was observed. While β‑diversity analysis indicated that the abundance of fifteen (15) genera in the PLf group and two (2) genera in the DLf group was found to be significantly different (p < 0.05). 16S rRNA sequencing results indicated that at the phylum level, in 14 ribs yaks Ascomycota, Basidiomycota, and Olpidiomycota, while in 15 rib yaks, Neocallimastigomycota, Mortierellomycota, and Rozellomycota were found to be significantly different (p < 0.05). At the genus level, Rhodotorula, Kluyveromyces, Comoclathris, Arthrinium, Cladophialophora, Seimatosporium, Lambertella, and Sphacelotheca in 14 rib yaks, and Orpinomyces, Ustilago, Fusarium, Aspergillus, Caecomyces, Alternaria, Trichoderma and Acremonium in 15 rib yaks were found to be significantly (p < 0.05) different. Predictive functional analysis based on ruminal fungal DNA sequences from 15‑rib yaks (DLf) demonstrated that genes involved in energy metabolism were upregulated. This study sheds novel insights into how genetic variations influence gut mycobiota in Jiani yak.

The study investigates the relationship between biofilm formation and antibiotic resistance in Escherichia coli (E. coli) isolated from calves. Using biochemical and molecular methods, we identified the isolates and assessed their biofilm-forming ability through an improved crystal violet staining method. The minimum inhibitory concentrations (MICs) of 18 antibiotics against the isolates were determined using the broth microdilution method. The impact of cefoxitin on biofilm formation was analyzed using laser scanning confocal microscopy (LSCM). Additionally, qRT-PCR was employed to evaluate the expression levels of biofilm-related genes (luxS, motA, fliA, pfs, and csgD) in response to varying cefoxitin concentrations. Results indicated a significant correlation between antimicrobial resistance (AMR) and biofilm formation ability. Cefoxitin effectively reduced biofilm formation of multidrug-resistant E. coli isolates at 1/2 and 1 MIC, with enhanced inhibition at higher concentrations. The QS-related genes luxS, pfs, motA, and fliA were downregulated, leading to decreased csgD expression. At 1/2 MIC, csgD expression was significantly reduced. In conclusion, cefoxitin inhibits biofilm formation in multidrug-resistant E. coli by down-regulating key genes, offering a potential strategy to mitigate resistance and control infections in calves caused by biofilm-positive E. coli isolates.

This study investigates the role of Perilipin1 (PLIN1) in milk fat synthesis in bovine mammary epithelial cells (BMECs) and its regulatory mechanisms, aiming to provide a foundation for improving milk fat content through molecular breeding. BMECs were used as a model to analyze the effects of PLIN1 overexpression (OE-PLIN1) and interference (si-PLIN1) on milk fat synthesis and lipid-related gene expression using RT-qPCR, Western blot, and Oil Red O staining. Results show that OE-PLIN1 significantly enhances triglyceride (TAG) accumulation in BMECs (P < 0.01), upregulates lipid synthesis-related genes (such as PPARγ, C/EBPα, C/EBPβ, FABP4, FASN) (P < 0.05), and downregulates the mRNA expression of lipid breakdown-related genes (HSL, ATGL) (P < 0.05). Conversely, si-PLIN1 significantly reduces TAG accumulation (P < 0.05) and lowers the expression of lipid synthesis and breakdown genes (P < 0.05). Additionally, OE-PLIN1 combined with SREBP1 siRNA interference (si-SREBP1) did not have a significant impact on the mRNA and protein levels of SREBP1, but it significantly altered SREBP1's phosphorylation, indicating that SREBP1 interference inhibits PLIN1's effect on milk fat synthesis. This study suggests that PLIN1 promotes milk fat synthesis in BMECs via regulating SREBP1 activity, offering a new strategy for enhancing milk fat content in dairy cattle.