Animal Bioscience最新文献

Objective: This study aimed to assess the impact of corn straw-based unfermented and fermented total mixed rations (TMR) supplemented with exogenous cellulase on the in vitro fermentation characteristics, growth performance, feeding behavior, apparent digestibility, rumen fermentation and digestive enzyme activities of Chinese Simmental bulls.

Methods: Unfermented (direct spraying of exogenous cellulase onto TMR, TMR) and fermented (exogenous cellulase fermentation for more than 7 d, fermented total mixed rations [FTMR]) TMR were collected, dried, powdered and used as fermentation substrates. The fermentation liquid was ruminal fluid collected from Chinese Simmental bulls. The artificial rumen culture fluid were continuously cultured in vitro for 48 h. Based on the diets they were fed, 24 healthy Chinese Simmental bulls (average weight of 495.93±10.89 kg) were randomly divided into two groups, with 12 bulls in each group, which were fed TMR or FTMR. The study lasted 56 d.

Results: In in vitro experiments, the neutral detergent fiber (NDF) degradability and total volatile fatty acid, propionate, iso-butyrate, iso-valerate and valerate concentrations were greater in the FTMR group (p<0.05) than in the TMR group. However, the methane production, pH and acetate/propionate (A/P) of the FTMR group tended to be lower (p<0.05) than those of the TMR group. In the in vivo experiments, the average daily gain, eating rate, and feed efficiency of the FTMR groups were greater (p<0.05) than those of the TMR group. Similarly, the NDF degradability of the FTMR group was greater (p<0.05) than that of the TMR group. Compared to those in the TMR group, the concentrations of total volatile fatty acids, iso-butyrate, propionate and butyrate were greater in the FTMR group (p<0.05), and the A/P ratio was lower (p<0.05). Similarly, cellulase, xylanase, and β-glucosidase activities were greater (p<0.05) in the FTMR group than in the TMR group.

Conclusion: Corn straw-based FTMR supplemented with exogenous cellulase play a vital role in decreasing the structural carbohydrate content of TMR and ruminal methane production in vitro, improving nutrient digestion and absorption, optimizing rumen fermentation, and improving the growth performance of beef cattle.

Objective: Dermal papilla cells (DPCs) play a pivotal role in hair follicle development and can modulate melanogenesis in melanocytes (MCs) through their microenvironment. Our previous studies have demonstrated that the levels of exosomal miR-222-3p derived from DPCs of white Rex rabbits are significantly higher than those of black Rex rabbits. However, the specific role and underlying molecular mechanisms of exosomal miR-222-3p in melanogenesis remain elusive.

Methods: DPCs and MCs were isolated from hair follicles of Rex rabbits and identified using western blotting (WB) and immunofluorescent staining. Exosomes derived from DPCs (DPCs-exos) were characterized using nanoparticle tracking analysis, transmission electron microscopy, and WB. To investigate cell-cell crosstalk mediated by exosomes, MCs were co-cultured with CM-Dil-labeled DPCs-exos. The expression of miR-222-3p in skin tissue and exosomes was quantitatively assessed using quantitative real-time polymerase chain reaction. The transmission of DPCs-secreted exosomal miR-222-3p to MCs was demonstrated using Cy3-labeled miR-222-3p in conjunction with transwell assays. The impact of miR-222-3p on melanin synthesis was evaluated using the NaOH method, cell counting kit-8, and annexin V-fluorescein isothiocyanate/propidium iodide assays. Sex determining region Y-box 10 (SOX10), a potential target gene regulated by miR-222-3p, was validated using a dual-luciferase reporter assay, site-specific mutation, and WB.

Results: Increased levels of miR-222-3p were observed in the skin and DPCs-exos of white Rex rabbits compared to those of black Rex rabbits. Effective internalization of CM-Dillabeled DPCs-exos by MCs was observed. Furthermore, exosomal miR-222-3p derived from DPCs was transferred to MCs. Functionally, miR-222-3p significantly inhibited MCs proliferation, induced apoptosis and inhibited melanin synthesis. SOX10 was confirmed as a direct target of miR-222-3p in this regulatory cascade.

Conclusion: The findings demonstrate that exosomal miR-222-3p, derived from DPCs, suppresses melanogenesis in MCs by targeting SOX10, thus unveiling a novel mechanism of exosome involvement in melanogenesis.

Objective: This study aimed to develop genomic and phenotypic indices for beef cattle selection that afford progeny with reduced birth weight and fattening period. The indices should also allow regulating total weight gain during the fattening period and avoid marked increases of inbreeding.

Methods: Whether addition of constraint on total weight gain to constraints on body weight gain at up to four specific time points during the fattening process was effective for the weight gain until the end of the fattening period was examined in two selection indices with the selection trait being a phenotypic or a genomic breeding value random regression coefficient.

Results: Both indices afforded cattle with desired weight gains at specific time points and desired total weight gains. One cycle of index-based selection made it possible to shorten the fattening period two weeks compared with that before selection while maintaining the same final fattening weight as before selection. The impact of constraining total weight gain was smallest when the number of weight gain constraints at specific time points was three or four. However, constraining total weight gain was necessary to avoid poor total weight gain when the number of weight gain constraints at specific time points was only one or two.

Conclusion: The developed indices make it possible to regulate total weight gain during the fattening process and to achieve desired weight gains at specific time points. Importantly, the indices bring about genetic improvement without an excessive increase of inbreeding. Thus, we expect that these indices will contribute to sustainable genetic improvement in cattle while maintaining genetic diversity.

Objective: The active metabolite of vitamin A, all-trans retinoic acid (ATRA), is involved in the proliferation and differentiation of granulosa cells, and promotes the follicular development, oocyte maturation, and ovulation in mammals. This study aims to investigate the ATRA induced potential long noncoding RNAs (lncRNAs) that regulate the expression of genes associated with granulosa cell proliferation and follicular development.

Methods: The lncRNA and mRNA profiles of porcine granulosa cells from ATRA treatment and control group in vitro were constructed through RNA sequencing. Meanwhile, the sequencing data were verified using quantitative polymerase chain reaction (qPCR).

Results: A total of 86 differentially expressed lncRNAs and 128 differentially expressed genes (DEGs) were detected in granulosa cells after ATRA treatment. The quantitative real-time PCR (qRT-PCR) results were consistent with the RNA-seq data. Functional annotation analysis revealed that the DEGs were remarkably enriched in ovary function and reproduction which contained FoxO, Hippo, Oocyte meiosis, mammalian target of rapamycin signaling pathway, as well as several pathways associated with hormone regulation like oxytocin signaling pathway and steroid hormone biosynthesis. Moreover, an interaction network of lncRNAs and their cis-target DEGs was constructed, and 7 differentially expressed lncRNAs and 6 cis-target DEGs were enriched in ovarian steroidogenesis and reproduction.

Conclusion: These findings expand the lncRNA catalogue and provide a basis for further studies on the mechanism of ATRA-mediated lncRNA regulation of follicular development in pigs.

Objective: This study aims to verify the protective effect of the Kelch-like ECH-associated protein1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways by studying the effect of plasmids containing Nrf2-small hairpin RNA (shRNA) interference down-regulation of Nrf2 on zearalenone (ZEA)-induced intestinal porcine epithelial cells (IPEC-J2) oxidative stress.

Methods: We constructed an IPEC-J2 model that interferes with Nrf2 expression, set blank (control), negative control group (Sh-control), positive control group (Sh-Nrf2), and added 10, 20, and 40 μmol/L ZEA experimental group (Sh-Nrf2+ZEA10, Sh-Nrf2+ZEA20, and Sh-Nrf2+ZEA40).

Results: The study results showed that, compared with the Sh-Nrf2 group, ZEA significantly increased the apoptosis rate of IPEC-J2 in a time- and dose-dependent manner. Compared with the Sh-Nrf2 group, the activities of total superoxide dismutase and glutathione peroxidase and relative expressions of Keap1 at mRNA and protein level in the Sh-Nrf2+ZEA20 and Sh-Nrf2+ZEA40 groups were significantly reduced, the malondialdehyde level, and the fluorescence intensity around and within the nucleus of reactive oxygen species and Nrf2, and the relative expressions of Nrf2, quinone oxidoreductase 1, and hemeoxygenase 1 at mRNA and protein level significantly increased.

Conclusion: These results further prove that interfering with the expression of Nrf2 in IPEC-J2 cells affected the activation of the Keap1-Nrf2 signaling pathway and reduced the ability of cells to resist ZEA-induced oxidative stress. Therefore, the Keap1-Nrf2 signaling pathway had an important protective effect in ZEA-induced intestinal oxidative stress.

Genomic studies of diseases can be divided into two types: i) analyses that reveal causal genes by focusing on linkage disequilibrium between observed and causal variants and ii) those that simultaneously assess numerous genetic markers to estimate the polygenic effects of a particular genomic region or entire genome. The field of human genetics has emphasized the discovery of causal genes, but these represent only a fraction of the total genetic variance. Therefore, alternative approaches, such as the polygenic risk score, which estimates the genetic risk for a given trait or disease based on all genetic markers (rather than on known causal variants only), have begun to garner attention. In many respects, these human genetic methods are similar to those originally developed for the estimation of breeding values (i.e., total additive genetic effects) in livestock. However, despite these similarities in methods, the fields of human and animal genetics still differ markedly in terms of research objectives, target populations, and other characteristics. For example, livestock populations have continually been selected and inbred throughout their history; consequently, their effective population size has shrunk and preferred genes (such as those influencing disease resistance and production traits) have accumulated in the modern breeding populations. By examining the characteristics of these two fields, particularly from the perspectives of disease and disease resistance, this review aims to improve understanding of the intrinsic differences between genomic studies using human compared with livestock populations.

Cell growth and metabolism necessitate the involvement of amino acids, which are sensed and integrated by the mammalian target of rapamycin complex 1 (mTORC1). However, the molecular mechanisms underlying amino acid sensing remain poorly understood. Research indicates that amino acids are detected by specific sensors, with the signals being relayed to mTORC1 indirectly. This paper reviews the structures and biological functions of the amino acid sensors identified thus far. Additionally, it evaluates the potential role these sensors play in the developmental changes of the livestock production.

Purpose: The aim of the present study was to evaluate the effects of dietary beta-glucans supplementation for gestation and lactation sows of 1st, 2nd or 3rd parity on sows and litters performance, milk composition and Brix value of colostrum, hemogram and serum immunoglobulin G concentration of sows and piglets.

Methods: A total of 78 sows were distributed in a completely randomized design, in a 2x3 factorial scheme, with two supplementation levels (0 and 450 mg/kg of beta-glucans) and three parities (1st, 2nd or 3rd).

Results: No interaction was observed between supplementation and parturition for any of the analyzed variables. The dietary supplementation of purified beta-glucans did not influence the reproductive performance of sows, litter performance and the immune response of 1st, 2nd or 3rd parity sows during gestation and lactation. Third parity sows had heavier litters at farrowing, greater weight gain, higher colostrum Brix value and serum immunoglobulin G than 1st and 2nd parity sows.

Conclusion: It is concluded that dietary supplementation of beta-glucans for gestation and lactation sows of 1st, 2nd or 3rd parity did not affect performance of sows and litters; however, 3rd parity sows had heavier litters, greater weight gain at weaning, higher values of colostrum Brix and serum immunoglobulin G than 1st and 2nd parity sows.

Objective: This paper aimed to evaluate the effects of a multi-strain probiotic as natural feed additives on the productive performance, blood parameters, antioxidant defence, caecal short‑chain fatty acid profile as well as the effectiveness on the intestinal morphology and on the equilibrium modification of caecal microbiota of growing rabbits.

Methods: Eighty-six-week-old Italian White rabbits were assigned into two dietary groups: the control group was fed without any additive, while the test group received a diet supplemented with a multi-strain probiotic (MS-Prob; Slab51®) at a dosage of 250 mg/kg diet. The feeding trial lasted up to 12 weeks of age.

Results: Rabbits MS-Prob diet had significantly higher daily and final body weight recording also the best of feed efficiency compared to control group. Rabbits in MS-Prob group showed improved slaughter weight and carcass dressing yield. No significant effect was found on meat protein, lipids and ash contents. Serum total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides decreased significantly in rabbits fed the test-diet. In rabbits fed MS-Prob, the activity of glutathione peroxidase (GPx), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) increased significantly, whereas the level of thiobarbituric acid-reactive substance (TBARS) decreased significantly. Caecal pH, ammonia-N and total volatile fatty acids (VFAs) were not significantly influenced by dietary treatments. Conversely, VFAs molar proportions were statistically affected by diets, with higher acetic and butyric acid concentrations in caecum of rabbits fed MS-Prob. Feeding of MS-Prob reduced harmful bacterial growth (Escherichia coli, Bacillus spp., Clostridium spp.) while promoting beneficial bacteria (Lactobacillus spp., Bacteroides spp.). Moreover, MS-Prob positively influences rabbit gut histomorphology, showing higher villus height, villus width, and crypt depth.

Conclusion: s: This study indicated that MS-Prob (Slab51®) supplementation stimulated the performance of growing rabbits and positively affected blood serum parameters, intestinal morphology, and caecal environment and microbiota.

Objective: This study aimed to investigate the effect of dietary nanoselenium (nanoSe) and sodium selenite (SS) on the concentrations of selenoamino acids, the activities of selenoenzymes, and the mRNA expressions of selenoproteins in the milk of peripartal dairy cows.

Methods: Three diets included a control (basal diet) with background selenium at 0.06 mg/kg and treatments with either SS or nanoSe added at the same selenium concentration of 1.00 mg/kg of diet. A total of 45 dairy cows were randomly allocated to three groups. The feeding trial lasted for 42 days from prenatal 21 days to postnatal 21 days.

Results: NanoSe increased (p<0.05) milk yield compared to the control and SS. In milk, both SS and nanoSe increased (p<0.05) the concentrations of selenium, selenocysteine, and selenomethionine, and the activities of glutathione peroxidase 4, glutathione reductase, thioredoxin reductase, glutathione S-transferase, and iodothyronine deiodinases (Type 2 and 3). The nanoSe showed higher (p<0.05) effects on these parameters than SS. Also, dietary nanoSe upregulated (p<0.05) the mRNA expressions of selenoproteins P, W, S, F, M, N, K, O, H, and I in milk compared to the control. For most selenoproteins, there was no difference between SS and nanoSe, only selenoprotein K was higher (p<0.05) in nanoSe than in SS.

Conclusion: In conclusion, dietary nanoSe increased milk yield, milk selenoamino acids and selenoproteins in peripartal dairy cows.