Animal Bioscience最新文献

Objective: The objective of this study was to evaluate the effects of inactive (heat-killed) Clostridium butyricum (ICB) on gas production kinetics, fermentation parameters, and microbiota with varying media pH levels in batch culture.

Methods: The in vitro experiment was designed as a completely randomized factorial arrangement, with 2 media pH levels (5.8 and 6.5)×2 Clostridium butyricum (CB) products (active and inactive)×4 dosages of CB. Two lactating dairy cows with ruminal fistulas, fed a diet comprising 40% forage and 60% concentrate, served as donors for rumen inoculum. Following 24 h of incubation, the gas production, dry matter disappearance (DMD), volatile fatty acid (VFA), ammonia nitrogen (NH3-N) and microbial profile were measured to determine the effect of treatment on fermentation.

Results: The gas volume (GV), DMD, total VFA concentration, NH3-N concentration, acetate concentration and microbial alpha diversity were inhibited when the media pH decreased from 6.5 to 5.8. Increasing the supplemental doses of ICB linearly increased the GV, DMD (trend) and butyrate proportion at media pH 6.5. Moreover, the increasing supplemental dose of active Clostridium butyricum (ACB) linearly increased GV, butyrate proportion and NH3-N concentration (trend) regardless of media pH, and linearly increased DMD, total VFA concentration and A:P ratio at media pH 6.5. Supplementing ICB decreased the relative abundance of Actinobacteria and Butyrivibrio in the fermentation fluid.

Conclusion: Increasing media pH promotes rumen fermentation and alter bacterial community. Although both ACB and ICB have the potential to stimulate rumen fermentation in a dose-dependent manner, their effects change depending on media pH levels. Furthermore, both ACB and ICB rarely altered the rumen bacterial community.

Objective: This study explored the effects of different dietary crude protein (CP) levels on the cecal transcriptome and microbial composition in weaning pigs.

Methods: Ninety-six weaning pigs were randomly assigned into three groups designated as H, M, and L groups. The H, M, and L groups were administered 20% and 18%, 18% and 16%, and 16% and 14% CP during the early (1-14 days) and late phases (15-28 days), respectively.

Results: The final body weight and average daily gain in the L group were significantly lower than those in the other groups (p = 0.008). The feed conversion ratio was lower in the H and M groups than in the L group (p = 0.01). Cecal transcriptome analysis revealed that heatmap and principal component analysis of differentially expressed genes indicated the presence of distinct clusters among the groups. Genes associated with cell proliferation and differentiation and inflammation were down-regulated in the M and L groups, compared with corresponding genes in the H group (p<0.001). Pathway enrichment analysis suggested that genes related to IL-17 signaling pathway was down-regulated in the M and L groups (p<0.05). Beta diversity analysis and heatmap for microbial composition and function indicated the presence of distinct clusters among the groups. Carbohydrate-fermenting bacteria, such as Megasphaera elsdenii DSM 20460 and Blautia luti DSM 14534, exhibited higher levels in the M and L groups compared with the H group (p≤0.05). The abundance of Lactobacillus amylovorus DSM 20531 was significantly greater in the M group than in the other groups (p≤0.05). The abundance of L. amylovorus DSM 20531 was positively correlated with growth performance. Integrated multi-omics analysis suggested significant similarities between the cecal transcriptome and microbiota (p<0.01).

Conclusion: Reducing CP levels modulates cell growth and alleviates inflammation in the cecum. A low CP diet causes cecal microbiota composition shift and promotes the proliferation of carbohydrate-fermenting bacteria. Overall, 18% CP in an early phase and 16% CP in a late phase can substantially improve growth and gut health in weaning pigs.

Objective: This study aimed to compare the effects of natural palygorskite (Nat-Pal) and crystal bundles disaggregated palygorskite (Dis-Pal) supplementation on the growth performance, intestinal health, and digestive function of young broilers.

Methods: A total of 400 male Arbor Acres broilers (one-day-old) were randomly assigned to five experimental groups with eight replicates over a 14-day experimental period. Chicks were fed a basal diet (Control group), the basal diet supplemented with 10 g/kg Nat-Pal or 2.5, 5, and 10 g/kg Dis-Pal, respectively.

Results: Dis-Pal linearly increased average body weight and average daily gain, and decreased feed-to-gain ratio of broilers from days 1 to 14, with the 5-10 g/kg Dis-Pal showing the most pronounced effects (p<0.05). An addition of Dis-Pal linearly increased glucose level, and decreased triglyceride level in serum (p<0.05). Compared to the control group, 5 g/kg Dis-Pal increased the digestibility of crude protein and dry matter, enhanced trypsin, lipase, and amylase activities in jejunal digesta, and elevated the ratio between villus height and crypt depth in jejunum and ileum (p<0.05). Dis-Pal linearly increased ileal mucosal glutathione and total antioxidant capacity levels, as well as total superoxide dismutase and catalase activities, with 10 g/kg Dis-Pal addition showing the best effects (p<0.05). The 2.5-10 g/kg Dis-Pal decreased the interferon-γ and tumor necrosis factor-α levels in ileal mucosa compared to the control group (p<0.05). Moreover, Dis-Pal supplementation linearly increased interleukin-10, secretory immunoglobulin A, and immunoglobulin M levels, and decreased the interferon-γ level, quadratically increased total superoxide dismutase and catalase activities in jejunal mucosa (p<0.05).

Conclusion: Dietary Dis-Pal supplementation could improve growth performance, intestinal health, and enhance the nutrient digestibility of young broilers. Supplementation with Dis-Pal was more advantageous for broilers than with Nat-Pal, and its optimal dosage was 5 g/kg.

Objective: Germ cell identity is regulated by the coordinated action of multiple key transcription factors during embryonic development, which includes the induction and control of germ-line-specific gene expression. The expression of DEAD-box helicase 4 (DDX4) and deleted in azoospermia-like (DAZL) genes in chickens plays a pivotal role in germplasm formation and the specification of germ cell lineage from a totipotent genome. This study aimed to investigate the regulatory mechanisms underlying germ cell fate determination.

Methods: Large-scale gene expression profiling was conducted to screen and select critical transcription factors. This analysis identified differentially expressed genes in chicken primordial germ cells (PGCs), comprising 1,020 transcription factors. Additionally, we generated a chicken DF1 cell line featuring an enhanced green fluorescent protein (eGFP) reporter precisely knocked into the transcriptional start site of the DAZL gene using the CRISPR-Cas9 system, enabling real-time monitoring of DAZL expression during reprogramming.

Results: Through analysis of transcription factor binding sites within approximately 10 kb upstream regions of DDX4 and DAZL, resulting in the selection of 10 candidate transcription factors for germ cell induction. Subsequently, the ten transcription factors identified as regulators of germ cell identity were transduced into the DAZL-knock-in eGFP DF1 cells. This approach led to the successful induction of eGFP-expressing cells in vitro, driven by the endogenous DAZL promoter. We conducted further characterization of these cells to confirm their germ cell-specific properties.

Conclusion: Our findings offer new insights into the transcriptional regulation of chicken germ cells by identifying key factors that activate DAZL expression. These results indicated valuable opportunities for advancing germ cell induction from somatic cells, with potential applications of in vitro models for studying germ cell-specific gene regulatory pathways in avian species.

Objective: The ovary, as an important reproductive organ, tightly regulates the litter size of rabbits through its complex network of genes. This study aims to identify candidate genes related to litter size in rabbits through RNA sequencing and to analyze the regulatory effects of C-X-C motif chemokine ligand 12 (CXCL12) on granulosa cells (GCs).

Methods: This study used ovarian transcriptome sequencing to identify differentially expressed genes between the ovarian tissues of New Zealand female rabbits with high (H) and low (L) litter sizes. In addition, a new candidate gene which was highly expressed in group H, namely the chemokine ligand CXCL12, was selected for further verification of biological functions.

Results: The cell counting kit-8 assay and flow cytometry analysis showed that CXCL12 can promote GCs proliferation but inhibit their apoptosis. Furthermore, quantitative reverse transcription polymerase chain reaction and western blotting indicated that CRABP1 regulated genes (PCNA, CCND1, CDK2, Bcl-2 and Bax) and proteins (CCND1, PCNA, Bcl-2 and Bax) related to cell cycle and cell proliferation. In addition, it can also regulate the expression levels of genes (TAF4B, CITED1, WNT2, WNT10B, and HSD17B1) and proteins (CITED1 and WNT10B) related to follicle development and litter size. Finally, it was found that CXCL12 targeted the CXCR4 receptor to activate the JAK/STAT signaling pathway.

Conclusion: We utilized bioinformatics to screen 184 genes potentially associated with litter size in New Zealand female rabbits. Among these, CXCL12 plays a role in regulating the expression of cell cycle-related genes, promoting GCs proliferation. As a result, CXCL12 emerges as a promising candidate marker for selecting high litter size female rabbits in future breeding and production practices.

Objective: The aim of this experiment was to integrate production indices with omics sequencing to elucidate the systemic perturbations between hepatic metabolism and the gut microbiota during overfeeding.

Methods: A total of 120 seven-week-old male Landes geese were floor-reared in a pen environment. Overfeeding commenced at week 8 using a corn-based diet containing 5% soybean oil. The feeding regimen consisted of three daily meals (150-180 g/meal) initially, gradually increasing to five meals (300-500 g/meal) after two weeks, and was maintained for a total overfeeding period of four weeks.

Results: The results demonstrated that overfeeding significantly increased liver weight and serum lipid levels, accompanied by intracellular lipid droplet accumulation. Concurrently, the downregulation of taurine-conjugated bile acids and the upregulation of free bile acids disrupted cholesterol homeostasis. Crucially, overfeeding triggered gut microbial dysbiosis characterized by Escherichia-Shigella enrichment and norank_o_Clostridia_UCG-014 depletion.

Conclusion: Our work demonstrated that the identification of the "gut microbiota‒bile acid‒liver axis" could serve as a pivotal signaling pathway driving overfeeding-induced foie gras formation while providing a theoretical foundation for overfeeding strategies to mitigate metabolic pathologies in waterfowl production.

Objective: Body conformation traits directly impact carcass performance in the meat goat industry. This study explored the population genetics of two Chinese goat breeds and identified the genomic variants associated with their body conformation traits.

Methods: The Guizhou black goat (GBG, n = 104) and Hezhang black goat (HBG, n = 100) underwent genotyping through whole-genome sequencing and phenotyping by measuring their body height (BH), body length (BL), chest depth (CD), chest width (CW), chest girth (CG), rump width (RW), rump height (RH), and cannon circumference (CC).

Results: The relatedness analysis showed that these goats exhibited low genetic kinship-related, with the GBG and HBG being relatively independent, albeit with some genetic introgression present. The lambda values showed that the reliability of the genome-wide association studies (GWAS) model, identifying a total of 33, 1, 6, 2, 5, 10, 21, and 13 single nucleotide polymorphisms (SNPs) as significantly correlated (p<8.33e-8) with BH, BL, CD, CW, CG, RW, RH, and CC, respectively. The GWAS for BH and RH identified the greatest number of significant SNPs, with a substantial overlap among them, mainly located in four regions: chr13_63286230-69784740 (10 SNPs), chr14_60354209-60376549 (six SNPs), and chr15_65605417-73873841 (five SNPs), and chr23_42819635-43332716 (nine SNPs). Individuals with a greater number of these SNPs displayed elevated BH and RH values. Following the annotation of all significant SNPs, 102 genes within a ±100 Kb region were identified. The most significantly enriched KEGG pathway was "Olfactory transduction", while the most significantly enriched GO terms included "cellular process" and "molecular transducer activity".

Conclusion: This study investigated the population genetics of two prominent Chinese goat breeds and identified several SNPs that are significantly associated with body conformation traits. These findings offer biological insights into enhancing growth performance and hold significant potential for practical application in the genomic selection of meat goats.

Objective: Imbalanced feeding of protein and energy in ruminants coupled with increasing concerns over low production efficiencies and high livestock emissions intensifies the feeding challenges, especially in buffaloes. This study was planned to evaluate the independent or interactive effects of dietary starch and crude protein (CP) on lactation performance, blood metabolites, and methane production of dairy buffaloes.

Methods: Sixteen lactating multiparous Nili Ravi buffaloes received the following dietary treatments of low (LS) or high starch (HS) content combined with low (LP) or high protein (HP) content in a 4×4 Latin square design: 1) LSLP, 2) LSHP, 3) HSLP, and 4) HSHP. Dietary starch contents were 19.5% and 28.7% in LS and HS diets, whereas CP contents were 8.8% and 10.6% in the LP and the HP diets, respectively.

Results: Although milk yield was not affected by dietary treatments, the HP diet increased milk protein and lactose contents compared with the LP diet in the HS group; however, no such increase was observed in LS group, resulting in a starch×CP interaction. Efficiencies of metabolizable protein and milk nitrogen decreased with the HP diet compared with the LP diet. Metabolic efficiency of metabolizable protein was higher in buffaloes fed the LS diet compared with HS diet. Rumen pH decreased with the HS diet compared with the LS diet in the HP group; however no such change was observed in the LP group. Methane production was increased with the LS diet compared with the HS diet. Contrarily, methane production was decreased in buffaloes fed HP diet compared with those fed the LP diet.

Conclusion: These findings indicated that dietary starch interacted with CP level for milk protein, milk lactose, rumen pH, and methane production of lactating buffaloes. Overall, HS combined with HP content can effectively improve milk protein and lactose contents while reducing the methane emission of lactating buffaloes.

Objective: This experiment evaluated the use of insect protein and phytonutrient-based tropical plant supplementation on rumen fermentation characteristics and microbial protein synthesis in Thai native beef cattle. Enhancing protein utilization and promoting rumen fermentation could be achieved by combining high-protein crickets and phytonutrients from mangosteen peel and lemongrass powder to a pellet (CMLP).

Methods: Four native male Thai beef cattle were randomly assigned treatments using a 4×4 Latin square design to receive four dietary treatments. The treatments were as follows: control (no supplementation), CMLP supplement at 50 g/h/d, CMLP supplement at 100 g/h/d and CMLP supplement at 150 g/h/d, respectively.

Results: Results revealed that the supplementation of CMLP in beef cattle did not influence rice straw intake, concentrate intake and total feed intake, which also enhanced the digestibility of crude protein, acid detergent fiber and neutral detergent fiber (p<0.05). Additionally, volatile fatty acid production of propionate and bacterial population were increased (p<0.05), and protozoal populations and production of methane decreased (p<0.05) with a higher level of CMLP supplementation. Furthermore, efficiency of microbial nitrogen synthesis significantly increased by increasing the level of CMLP supplementation, particularly at 150 g.

Conclusion: Our results suggested that CMLP supplementation, particularly at 150 g/h/d, enhanced nutrient digestibility, increased the propionic acid proportion, and promoted microbial protein synthesis while reducing protozoal populations and methane production. CMLP showed promise as an effective dietary protein supplement that improved rumen fermentation and performance of Thai native beef cattle.

Objective: Maximizing growth throughout the growth period is a practical goal in the beef industry. We developed a novel selection index, called the maximum growth index, that maximizes the growth throughout the growth process and simultaneously achieves the desired weight gain at designated time points by assigning arbitrary values to selection intensity.

Methods: We used a technique called Lagrange multipliers to maximize overall growth throughout the entire growth process and to restrict weight gains to desired amounts at specific times. We developed a selection index by applying random regression (RR) to the growth curve and using the genomically enhanced breeding values of the RR coefficients as selection index traits.

Results: Examples of the developed index was applied based on assumed data in Japanese Black steers. Selection to maximize growth during the growth period and to moderate birth weight yielded an upwardly convex curve for weight gain during the growth process, and the peak daily gain was greater and earlier than achieved without this selection. Under a selection intensity of 0.5, the index that constrained birth weight to decrease by 2.5 kg achieved the pre-selection final weight 8 weeks earlier than occurred without this selection.

Conclusion: We developed a beef cattle selection index that maximized total weight gain during growth yet constrained birth weight and other traits. The maximum growth index that we developed enables reductions in birth weight concurrent with increases in final weight, thus benefiting the beef industry by increasing final weight and preventing dystocia.