Animal Bioscience最新文献

Genomic selection (GS) has become an indispensable tool in the beef cattle industry, offering the potential to significantly increase genetic gain and prediction accuracy by integrating genomic, pedigree, and phenotypic information to estimate genomic breeding values. In the Korean Peninsula, Hanwoo cattle (HC) are valued for their exceptional marbling and distinct flavour. Thus, genetic improvement breeding programs for Hanwoo have been undertaken to improve beef production and profitability, with a particular focus on carcass and meat quality traits. The success of a breeding program incorporating genomic information in HC largely depends on prediction accuracy, making genomic prediction (GP) essential for accelerating genetic gain. Hence, breeders should acknowledge the superiority of GS and choose the most suitable prediction model depending on the genetic architecture and biological nature of the trait of interest. Several GP methods have already proven their ability in terms of carcass and meat quality traits over the traditional pedigree-based best linear unbiased prediction (PBLUP) method. Therefore, there are no alternative approaches to GS for breeders to accelerate the innovative development of Hanwoo beef cattle. Thus, the main objective of this review is to provide an overview of how GP methods are being applied to improve the ultimate meat quality of HC. Furthermore, this review presents the transversal analysis of interest in GS for Hanwoo breeders when choosing the best prediction method for specific traits. We believe this review literature would be a significant resource for future exploitation of Hanwoo's potential in the Korean beef industry.

Objective: Pelleted feed has multiple advantages in animal production, but its hardness may limit the intake of young lambs with underdeveloped teeth and digestive systems, especially when the feed contains alfalfa and is produced with a high compression ratio in small diameters. This study aimed to evaluate the effects of removing alfalfa from starter feed or post-pelleting crumbling on lamb performance. We hypothesized that crumbling pelleted feed could reduce hardness, thereby increasing intake and enhancing performance.

Methods: A total of 118 healthy, 7-day-old Hu lambs (4.02±0.94 kg) were allocated to three groups: (1) a pelleted starter with alfalfa (CON), (2) a non-alfalfa pelleted starter (NA), and (3) a crumbled starter with alfalfa (CA). Feed intake, growth performance, nutrient digestibility, and rumen microbial composition were measured.

Results: The CA group demonstrated significantly reduced pellet hardness than the CON and NA groups (p<0.05), while NA group had higher starch gelatinization (p<0.05). CA notably increased feed intake, particularly after day 21 (p<0.05), and achieved the highest overall intake, body weight and average daily gain from days 7-49. The interaction between feed type and sex had significant impacton the digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF). In male lambs, both NA and CA groups demonstrated significantly higher digestibility of NDF and ADF compared to the CON group (p<0.05). Rumen microbiota diversity was influenced by feed composition more than pellet form, with alfalfa inclusion affecting a greater number of microbial genera. Crumbling increased the abundance of Methanobrevibacter (p<0.05).

Conclusion: These findings suggest that post-pelleting crumbling using a roller mill enhances feed intake and growth performance in young lambs, while feed composition plays a predominant role in shaping rumen microbial diversity.

Objective: Precocious puberty can shorten reproductive cycles, enhance reproductive capacity, and reduce feeding costs. Consequently, precocious livestock are widely utilized in cross-breeding. This study aims to elucidate the key molecular mechanisms by which circular RNA (circRNA) regulates the sexual maturation of sexually precocious goats.

Methods: In this study, we analyzed the circRNA expression profiles of hypothalamic tissue from Jining grey goats at four distinct postnatal developmental stages (1 day, 2 months, 4 months, 6 months).

Results: A total of 23,993 circRNAs were identified across these stages, predominantly derived from exonic regions, with 1,052 circRNAs exhibiting differential expression. Additionally, competitive endogenous RNA (ceRNA) analysis suggested that novel_ circ_0002274/chi-miR-197-5p/ estrogen receptor 1 (ESR1) and novel_circ_0002274/chimiR-30c-3p/oxytocin/neurophysin I prepropeptide (OXT) may regulate sexual maturation in goats via the estrogen signaling pathway and the oxytocin signaling pathway.

Conclusion: This study contributes to understanding the function of circRNAs in hypothalamic regulation of sexual maturation and provides valuable insights for breeding superior goat breeds.

Objective: This study aimed to elucidate how dietary energy levels regulate the hypothalamic-pituitary-gonadal axis in Holstein heifers during initial breeding, with a focus on rumen microbiota-host interactions.

Methods: Forty-four pubertal heifers (398.96±6.56 kg BW, 12.72±0.02 months) were stratified by body condition score and estrous cyclicity, then randomly allocated to control (CON, 8.64 MJ/kg DM NEL) or high-energy (HE, 9.50 MJ/kg DM NEL) diets (n = 22/group). Although practical constraints limited pen replication, we implemented rigorous matching procedures: Pens were matched for surface area (120 m2), feed bunk space (0.8 m/head) and growth performance, serum biochemical/immune/antioxidant markers, reproductive hormones, rumen fermentation parameters, microbiota, and metabolome profiles were analyzed.

Results: The HE group exhibited elevated gonadotropins (follicle-stimulating hormone, luteinizing hormone [LH]) and prolactin (PRL), indicating enhanced hypothalamic-pituitary activity. Serum triglycerides increased, while immune markers showed the altered state of immunoregulation characterized by significant increases in interleukin (IL)-2 and IL-6, reductions in IL-4, and decreases in tumor necrosis factor-α and interferon-γ. Antioxidant capacity improved with lower malondialdehyde levels. Rumen pH decreased, accompanied by elevated total volatile fatty acid, bacterial crude protein, acetic acid, propionic acid, butyric acid, and valeric acid concentrations. Microbial shifts included Treponema and Prevotellaceae_UCG_003 showing positive correlations with PRL and LH, while Ruminococcus was associated with acetyl-CoA precursors through enriched pyruvate metabolism.

Conclusion: HE diets (9.50 MJ/kg NEL) enhance hypothalamic-pituitary signaling and rumen fermentation efficiency, advancing first-service conception rates by 15% (55% vs. 70%) in pasture-based systems. This strategy optimizes reproductive management in intensive dairy operations through microbiota-driven metabolic modulation.

Objective: This study aims to reveal the transcriptional regulatory mechanism and effects of poly(A)-binding protein nuclear 1 (PABPN1) on adipogenesis, along with associated polymorphisms.

Methods: Transcription factors were identified using dual-luciferase reporter assay, overexpression techniques site-directed mutagenesis, real-time quantitative polymerase chain reaction (qPCR), electrophoretic mobility shift assays and chromatin immunoprecipitation-qPCR. Preadipocyte differentiation was measured with gain- and loss-of-function, Oil Red O staining and extraction assays. Single nucleotide polymorphisms (SNPs) were identified with direct sequencing of PCR products in the promoter, and the effects of these SNPs on PABPN1 expression were identified with dual-luciferase reporter assay.

Results: CCAAT/enhancer-binding protein (C/EBP) α and β regulate PABPN1 expression by directly binding to its promoter. PABPN1 promotes the preadipocyte differentiation in pigs. Three SNPs were identified, with the Haplotype GCC mutation significantly increasing the promoter activity of PABPN1.

Conclusion: PABPN1 promotes the preadipocyte differentiation as a downstream gene of C/EBP α and β. Haplotype GCC may serve as a molecular marker for selection of fat traits in pigs.

Objective: The objective was to evaluate the effects of replacing soybean meal (SBM) with enzyme-treated soy oligopeptide (ESO) in nursery pig diets on intestinal health, growth performance, and feed preference.

Methods: In Exp. 1, 128 pigs (average 5.2 kg) were housed in pens (4 pigs/pen), assigned to 4 diets supplemented with 0%, 1%, 2%, or 3% of ESO, and fed for 32 d. On d 32, blood, tissues, and mucosa from the duodenum and jejunum were collected. In Exp. 2, 24 pigs (average 6.2 kg) were assigned to 6 pens (4 pigs/pen). Each pen had two separate feeders containing two diets with 0% or 2% of ESO for 27 d.

Results: Increasing dietary ESO tended to quadratically change serum tumor necrosis factor-α (p = 0.059; minimum at 1.6% of ESO) and duodenal villus height to crypt depth ratio (p = 0.062; maximum at 1.8% of ESO). Increasing dietary ESO linearly reduced feed intake both linearly and quadratically (p<0.05) during phase 2 (maximum at 0.9% of ESO). Increasing dietary ESO both linearly and quadratically changed (p<0.05) weight gain during phase 2 (maximum at 1.0% of ESO). Increasing dietary ESO linearly changed (p<0.05) and tended to quadratically change (p = 0.077) weight gain during the overall phase. Increasing dietary ESO tended to linearly change (p = 0.059) gain to feed ratio during phase 1 and quadratically change (p<0.05) gain to feed ratio during phase 2 (maximum at 1.4% of ESO). Feed preference of the diet containing 2% of ESO was negatively associated with post-weaning days (R2 = 0.542).

Conclusion: Gradually replacing SBM with ESO at levels from 1.4% to 1.8% enhanced intestinal health and gain to feed ratio, whereas exceeding 0.9% to 1.0% reduced feed intake and weight gain, suggesting that optimal level of ESO in nursery pig diets is 0.9%.

Objective: This meta-analysis aims to examine the efficacy of essential oils (EO) as an anticoccidial alternative on broiler chickens under coccidia challenged trials, focusing on performance indicators including average daily gain (ADG), feed intake (FI), feed conversion ratio (FCR), final body weight (BW), mortality, and intestinal lesion.

Methods: A random-effects model was performed using the metafor package in R software. In a subgroup meta-analysis, treatment groups including coccidia-infected birds [C+], C+ group treated with EO [C+EO] or antibiotics [C+AB], and a non-infected control group treated with EO or AB, were compared against the control group [CON].

Results: As expected, C+ birds had lower (p<0.001) final BW and ADG as well as higher (p<0.001) FCR. Administration of either EO or AB on birds with coccidiosis infection resulted in similar final BW, ADG, FI, and FCR with CON birds, suggesting the comparable effectiveness of EO and AB to alleviate the adverse effects of coccidiosis. Broilers on the C+ group exhibited increased small intestine damage as shown by the greater (p<0.001) lesion score, but the mortality was not different from CON and other treatment groups. The Eimeria oocyst count was lower on birds treated with EO than on the infected birds, with an average suppression of 42.11%. Meta-regression demonstrated that C+ birds had inferior FI and ADG than CON and C+EO birds. However, high heterogeneity between studies was identified in all measured outcomes as shown by I2>75%, suggesting wide variability among study conditions.

Conclusion: EO may serve as an alternative antibiotic to mitigate the negative impacts of coccidiosis infection in broiler chickens.

Objective: Sodium butyrate (SB) is a potentially useful feed additive; however, its effects on lipid metabolism in adipose and liver tissues of lambs are still not fully explored. This study systematically examined the effects and underlying mechanisms of dietary SB supplementation on lipid metabolism in lamb adipose and liver tissues from an adipose-blood-liver perspective.

Methods: Twelve 3-month-old male lambs (22.37±2.05 kg) were randomly divided into a control group and an SB group. We measured the adipose tissue cellular morphology and lipid metabolism-related indices in both adipose and liver tissues.

Results: The results indicated that SB significantly reduces abdominal and perirenal adipose tissue mass, as well as the average area and diameter of adipocytes (p<0.05). Dietary supplementation with SB activated adenosine 5'-monophosphate-activated protein kinase α1 (AMPKα1) in lamb adipose tissue, resulting in upregulated mRNA expression of hormone-sensitive triglyceride lipase (HSL) and downregulated mRNA expression of sterol regulatory element-binding protein 1 and fatty acid synthase (p<0.05). Simultaneously, adiponectin secretion and receptor expression in adipose tissue, as well as serum adiponectin levels, were significantly elevated (p<0.05). Moreover, dietary supplementation with SB increased the levels of tricarboxylic acid cycle metabolites in lamb liver, including oxaloacetate, citrate, cis-aconitate, and succinate (p<0.05), while simultaneously activating the liver AMPKα1 signaling pathway. These changes led to upregulated HSL, platelet glycoprotein 4, and long-chain acyl-CoA synthetase mRNA expression (p<0.05), thereby enhancing liver fatty acid metabolism.

Conclusion: In summary, dietary supplementation with SB alters adiponectin levels in lambs, activates the AMPK signaling pathway, promotes adipose tissue lipolysis, and regulates liver lipid metabolism. The findings provide valuable insights into the use of SB for managing lamb body fat reserves and offer a robust basis for further research in animal bioscience.

Objective: Poultry producers use alternative housing arrangements, such as free-range systems, to allow birds to express their natural behaviors and to enhance consumer confidence in poultry products. Free-range systems provide hens with access to open spaces and better airflow, offering opportunities for thermoregulation through natural behaviors such as seeking shade or dust bathing. Compared to confined cage conditions, this can help reduce the negative effects of heat stress. In this study, we examined the productivity of laying hens segregated for the naked neck gene (Na) and raised in two distinct housing systems.

Methods: A total of 540 laying hens, 24 weeks of age, were randomly assigned to a 2×3 factorial design consisting of three genotypes (NaNa, Nana, and nana) and two housing systems (wire cages and free-range pens). Productive performance, egg quality characteristics, immune response, and blood parameters were evaluated over a threemonth period during the hot summer season.

Results: The results showed that introducing the Na gene into chickens raised under hot climate conditions improved egg production, cell-mediated immunity, and eggshell strength. A significant reduction in blood cholesterol levels and the cumulative percentage of broken eggs was observed in naked neck genotypes (NaNa and Nana) compared to the normally feathered genotype (nana). Hens kept in cages produced significantly heavier eggs compared to those in the free-range system. Laying hens kept in a free-range system exhibited a higher relative yolk weight and an increased shell percentage. Additionally, a significant decrease in plasma cholesterol levels was found in layers raised in free-range systems compared to those in wire cages. Eggs produced by hens reared in free-range systems also had a darker yellow yolk color compared to those from caged hens.

Conclusion: Introducing the Na gene into laying hens raised in free-range housing could be beneficial for improving egg production, immunity, and egg quality under high ambient temperatures.

Objective: Establishing chicken primordial germ cells (PGCs) in vitro is critical for producing genetically modified (GM) chickens. Efficient and reliable isolation and cultivation of PGCs remain significant challenges in advancing avian genetic modifications. To address these challenges, we employed a streamlined and practical approach for the efficient isolation and stable cultivation of chicken gonadal PGCs.

Methods: Chicken gonadal PGCs were isolated from embryonic gonads, surgically removed and dissociated using trypsin. The PGCs were isolated by exploiting differential adhesion properties, allowing fibroblasts to attach while PGCs remained suspended. Cultivation was performed with mitotically inactivated SIM mouse embryo-derived thioguanineresistant (STO) feeder cells under optimized culture conditions.

Results: PGCs proliferated robustly, reaching over 105 cells within one month, which is comparable to previously reported methods. Characterization assays confirmed the expression of PGC-specific markers, including SSEA-1 and DAZL, along with pluripotencyrelated genes such as OCT4 and NANOG. Additionally, injected PGCs successfully migrated to recipient embryonic gonads, where their presence was confirmed by fluorescence analysis and PCR.

Conclusion: This study highlights the effectiveness of the STO feeder-based culture system in avian germ cell research, contributing to progress in the production of germline chimeric and GM chickens.