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Heterogeneity of nucleolar morphology in four‐cell mouse embryos after IVF: association with developmental potential

AbstractIn mammals, around fertilization, the nucleolus of embryos transforms into the nucleolus precursor bodies (NPBs), which continue to mature until the blastocyst stage, leading to distinct morphological changes. In our study, we observed two types of nucleolar morphology in mouse in vitro fertilized embryos at the four‐cell stage, which we refer to single nucleolus (SN) and multiple nucleoli (MN). To visualize nucleolar morphology, four‐cell embryos were immunostained with anti‐NOPP140 antibody. These embryos were categorized into five types based on the number of blastomeres carrying SN: SN4/MN0, SN3/MN1, SN2/MN2, SN1/MN3, and SN0/MN4, with percentages of 13, 27, 21, 23 and 9, respectively. Next, using a light microscope, we divided the four‐cell in vitro fertilized embryos without fixation into two groups: those with at least two blastomeres displaying SN (SN embryos) and those without (MN embryos). Notably, significantly more SN embryos developed into blastocysts and offspring at 18.5 dpc compared with MN embryos. Furthermore, SN embryos displayed a higher NANOG‐positive cell number at the blastocyst stage, significantly lower body and placental weights, resulting in a higher fetal/placental ratio. These findings suggest a close association between nucleolar state at the four‐cell stage and subsequent developmental potential.

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Rumen microbial composition associated with the non‐glucogenic to glucogenic short‐chain fatty acids ratio in Holstein cows

This study aimed to determine the physiological features and rumen microbial composition associated with the non-glucogenic-to-glucogenic short-chain fatty acids ratio (NGR). Holstein cows were housed in a free-stall barn with an automatic milking system and fed a partially mixed ration. Physiological and microbial analyses were performed on 66 datasets collected from 66 cows (50-250 days in milk). NGR was positively correlated with ruminal pH, relative abundances of protozoa and fungi, methane conversion factor, methane intensity, plasma lipids, parity, and milk fat, and negatively correlated with total short-chain fatty acids. To highlight the differences in bacterial and archaeal compositions between NGRs, low-NGR cows (N = 22) were compared with medium-NGR (N = 22) and high-NGR (N = 22) cows. The low-NGR group was characterized by a lower abundance of Methanobrevibacter and a higher abundance of operational taxonomic units belonging to the lactate-producing, such as Intestinibaculum, Kandleria, and Dialister, and the succinate-producing Prevotella. Our findings indicate that NGR affects the methane conversion factor, methane intensity, and blood and milk compositions. Low NGR is associated with a higher abundance of lactate- and succinate-producing bacteria and lower abundances of protozoa, fungi, and Methanobrevibacter.

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β‐glucosidase, driven by porcine transthyretin promoter, specific expression in the liver of transgenic mice

AbstractUnder the background of food security, using non‐grain feed instead of corn–soybean‐based feed is an effective measure to alleviate the food‐feed competition. While, non‐grain feeds are often rich in fiber, which cannot be digested by non‐ruminants. Producing heterologous enzymes in non‐ruminants to improve cellulose utilization rate is a new research strategy by transgenic technology. In this study, porcine transthyretin (TTR) promoter, signal peptide‐coding sequence (CDS), Saccharomycopsis fibuligera β‐glucosidase gene (BGL1)‐CDS, 6×His sequences fragments were fused into pGL3‐control vector to generate transgenic vector. Then, transgenic mice were generated by pronuclear microinjection of the linearized expression vectors. Transgenic mice and their offspring were examined by PCR‐based genotyping and copy number variation. Results showed that BGL1 was successfully integrated into the mouse genome and transmitted stably. Furthermore, reverse transcription‐polymerase chain reaction (RT‐PCR), Western blotting, and β‐glucosidase activity assay demonstrated that BGL1 was specifically expressed in the liver, and β‐glucosidase activity significantly increased. In addition, liver weight index, cellular morphology, and collagen fiber content of the liver showed that exogenous gene insertion did not cause any lesions to live. Taken together, our findings suggest that β‐glucosidase driven by TTR promoter was specifically expressed in the liver of transgenic mice.

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Genome‐wide detection of changes in allelic frequency in Landrace pigs selected for resistance to mycoplasma pneumonia of swine

Closed-pig line breeding could change the genetic structure at a genome-wide scale because of the selection in a pig breeding population. We investigated the changes in population structure among generations at a genome-wide scale and the selected loci across the genome by comparing the observed and expected allele frequency changes in mycoplasma pneumonia of swine (MPS)-selected pigs. Eight hundred and seventy-four Landrace pigs, selected for MPS resistance without reducing average daily gain over five generations, had 37,299 single nucleotide polymorphisms (SNPs) and were used for genomic analyses. Regarding population structure, individuals in the first generation were the most widely distributed and then converged into a specific group, as they were selected over five generations. For allele frequency changes, 96 and 14 SNPs had higher allele frequency changes than the 99.9% and 99.99% thresholds of the expected changes, respectively. These SNPs were evenly spread across the genome, and a few of these selected regions overlapped with previously detected quantitative trait loci for MPS and immune-related traits. Our results indicated that the considerable changes in allele frequency were identified in many regions across the genome by closed-pig line breeding based on estimated breeding value.

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Evaluation of modified dried vinasse as an alternative dietary protein source for broilers

AbstractThe increase in poultry production and the high cost of soybean led to the search for alternative protein sources. One of these sources is vinasse, a by‐product of the baker's yeast industry. Modified dried vinasse (MDV) can be produced for use in poultry nutrition by making some improvements in vinasse. Therefore, the present study aimed to examine the effect of the usage of MDV in broiler diets. A total of 192 daily male Ross 308 chicks were randomly assigned to four groups. MDV was included at the levels of 0%, 2%, 4%, and 6% in the diets for 42‐day trial. Linear significant improvements in the final weight, body weight gain, feed efficiency, and digestibility were seen with increasing MDV levels. The use of MDV caused a significant reduction in feed consumption. The relative weight percentages of abdominal fat and serum cholesterol concentration were reduced linearly with increases in MDV levels. MDV inclusion linearly decreased the malondialdehyde concentration, but increased 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity in breast meat significantly. The protein content in breast meat was increased with MDV. Cecal beneficial microorganisms and serum IgG levels were increased linearly with MDV. In conclusion, results suggested that MDV could be a feasible option for alternative protein sources for broilers.

Open Access
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Physicochemical properties and structural changes of chicken breast meat subjected to radio frequency tempering combined with conventional thawing treatments

Being able to thaw frozen meat in a reasonable time without impairing quality is crucial for industry and households. Radio frequency (RF) techniques have been used to defrost frozen foods. The influences of RF (50 kW, 27.12 MHz) tempering combined with water immersion (WI, 20°C) thawing (RFWI) or air convection (AC, 20°C) thawing (RFAC) on the physicochemical and structural changes of chicken breast meat were investigated, and the results were compared with those of the fresh meat (FM) and the meat samples subjected to WI and AC only. The thawing processes were terminated when the core temperatures of the samples reached 4°C. The results indicated that AC was the most time-consuming technique, whereas RFWI required the least amount of time. The moisture losses, contents of the thiobarbituric acid-reactive substance, total volatile basic nitrogen, and total viable counts of the meat subjected to AC were higher. Relatively less changes in water-holding capacity, coloration, oxidation, microstructure, protein solubility, and high sensorial acceptance were observed for RFWI and RFAC. This study demonstrated that the meat thawed using RFWI and RFAC was of satisfactory quality. Therefore, the RF techniques can be effective alternatives to the time-consuming conventional thawing methods and benefit the meat industry.

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Caveolae‐associated protein 3 promotes adipogenic differentiation of porcine preadipocytes by promoting extracellular signal‐regulated kinase phosphorylation

Fat deposition is one of the key factors affecting the economic development of pig husbandry. The aim of this study was to investigate the expression characteristics of caveolae-associated protein 3 (CAVIN3) and to elucidate its effect and mechanism on adipogenic differentiation of porcine preadipocytes. Cell transfection, quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot, and oil red O staining were used to detect the effect of CAVIN3 on the differentiation of porcine preadipocytes. The results showed that CAVIN3 was expressed in various tissues, with higher expression in adipose tissue, differentially expressed during cell adipogenic differentiation, and mainly distributed in the cytoplasm. Functional studies showed that, after CAVIN3 interference in preadipocytes, the expression of adipogenic factors and the content of lipid droplets were significantly decreased (p < 0.05). The results were reversed after CAVIN3 was overexpressed. The mechanism research showed that LY3214996 inhibited the extracellular signal-regulated kinase (ERK) phosphorylation and further inhibited lipogenic factors expression. Overexpression of CAVIN3 attenuates the inhibitory effect of LY3214996 on ERK phosphorylation and attenuates its inhibitory effect on adipogenic differentiation. Therefore, this study demonstrated that CAVIN3 promotes the differentiation of porcine preadipocytes by promoting ERK phosphorylation. The present study can lay a theoretical foundation for further studying the molecular mechanism of porcine fat deposition.

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