Animal Research and One Health最新文献

This article aims to establish a multiplex real-time polymerase chain reaction (PCR) assay for the simultaneous detection of Streptococcus suis (SS), Streptococcus suis serotype 2 (SS2), and Glaesserella parasuis (GPS). In this study, three pairs of primers and three probes were designed based on the specific sequences of SS (gdh), SS2 (cps2j), and GPS (infB). The results showed that the assay was not cross-reacted with other swine pathogens (Escherichia coli, Pasteurella multocida, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, and Enterococcus faecalis; Streptococcus pyogenes). 10⁸ to 10² copies/μL showed the R² values for SS, SS2, and GPS were 0.999, 0.992, and 0.990, respectively. The multiplex real-time PCR efficiency was 93.816% for gdh, 105.260% for cps2j, and 93.175% for infB. The sensitivity result showed that SS, SS2, and GPS could be detected at 10 copies/μL. The repeatability result showed that intra-assay and inter-assay coefficients of variation of SS, SS2, and GPS were <2%. The best cutoff values for SS, SS2, and GPS were determined from ROC curves to be 35.085, 35.620, and 34.940, respectively. Areas under the curve were 0.943, 0.968, and 0.958. In total, 88 clinical samples were analyzed. The results indicated positive rates of 11.364% (10/88) for SS, 20.455% (18/88) for SS2, and 18.182% (16/88) for GPS. In conclusion, the developed one-step multiplex real-time PCR assay may be a valuable tool for the early detection of the SS, SS2 and, GPS with high specificity and sensitivity.

Duck viral hepatitis (DVH), mainly caused by duck hepatitis A virus genotype 3 (DHAV-3) in China, is an important disease affecting Pekin ducks. Using artificial selection breeding based on genealogical and phenotypic observations, a susceptible line (Z7) and a resistant line (Z8) of Pekin ducks to DHAV-3 were identified. Here, we performed a genome-wide analysis to identify selected genes in the genomes of Pekin ducks underlying resistance/susceptible breeding. Following selection, the mortality rate of the Z8 line reduced from 59.2% to 7.8% in the fourth generation (Z8G4), whereas the death rate of the Z7 line increased from 67.5% to 81% in the third generation (Z7G3). Moreover, directed breeding caused the allele frequencies of Z8 and Z7 changing in opposite direction, accompanied by declines in genomic genetic diversity. With the G0 generation as the reference group, a total of 49 selected genes were identified in the Z7-susceptible population and 109 selected genes in the Z8-resistant population based on the top 5% F_ST and PI ratio, and two candidate key genes were further fine-mapped. Susceptibility selection led to 17 mutations in the LRIG3 gene in the Z7 population (chr1: 169,757,982–169,772,687), and resistance selection led to 134 mutations in the CRHR2 gene in the Z8 population (chr2: 4,190,154–4,273,970). Our results provide new insights into the resistance and susceptibility to DHAV-3 and lay a theoretical foundation for further research on the mechanism of resistance/susceptibility of Pekin ducks to DHAV-3.

I was taking the night train to Nanyang in China's Henan province and spent the last hour before I reached my destination looking at mile upon mile of maize, or corn as it’s often known. Most of this crop in China and worldwide is grown largely for animal feed and biofuel. The air was dampened by a gray, misty haze. I was keen to visit some of China's animal production facilities but for now I found myself looking out over what was being used to feed them. Vast prairie-like tracts of a single crop stretching as far as the eye could see. So much so, that it made it feel like the train was moving in slow motion.

Thinking back on that journey reminds me of something that happened some years later much closer to home.

It was early morning in a field near the farm hamlet where I live in England, and a tractor was pulling a plough. Back and forth it went, ploughing its lonely furrow. Behind the tractor, dust clouds spiraled and caught the sun, creating an aura. A timeless symbol of the season. Only, something was missing: there were no screeching gulls following the plough in search of worms.

I took a closer look. The tractor was ploughing across a footpath, giving me a bird's-eye view of the newly upturned soil. As I stared down, do you know what I saw?—nothing. There were no worms, beetles, or bugs desperate to get back into the newly upturned earth. The soil was lifeless. It was like sand. We could have been walking on the moon.

That field should have had millions of worms in every hectare—in every patch the size of a football pitch. There should have been 13,000 species of life with a collective weight of an elephant: five tons.

But instead, there was nothing.

That field was about to be planted again with maize (corn), a crop commonly used as animal feed. It was grown with chemical pesticides and artificial fertilizers. No wonder the soil was dead and washing into the nearby river. It is a problem that exists for crops grown using industrial methods, whether for human consumption or the sizeable industry for animal feed, which accounts for about a third of cereal crops grown worldwide.

It reminded me of seeing great green swathes of monoculture maize corn in the American Midwest of Nebraska, much of which was destined for the feed troughs of industrially reared chickens, pigs, and cattle. I remember seeing feedlots. Hundreds of cows and calves standing in barren pens, not a blade of grass in sight. Despite the hot summer sun, they had no shade. I watched as they jostled in the searing heat for respite, trying to get into each other's shadow.

It was a potent example of industrial animal agriculture, a regime that now ravages the planet, to the detriment of animal welfare, the ecosystem, and the health of people.

It has not always been like this. In fact, it was but a single human lifetime ago when we started removing animals from the land to be caged, crammed, and confined. Taken off grass whe

Genotyping plays an important role in breeding and population studies. Currently available genotyping technologies, including solid-phase chips and sequencing, often have several limitations in their application to local chickens in China, including high costs, insufficient diversity, and poor universality. In the present study, we developed a chicken 5 K single nucleotide polymorphism (SNP) array suitable for breeding and genetic analysis using genotyping by targeted sequencing technology. The chip design was based on genomic data from 33 local breeds, and 5847 SNPs were selected for the final chip design. Among these SNPs, 3427 sites were associated with economic traits in broiler chickens. Our chip contained 25,000 high-quality SNP markers captured from 5 K regions with highly efficient target site capture. Population analyses of the eight breeds showed high detection rates and minor allele frequencies for SNP markers on the array, enabling clear differentiation of different populations and families within populations. The genetic diversity trend obtained using the chip was consistent with the results obtained from microsatellite analyses. Additionally, the 5 K array was applied to a genome-wide association study of broilers, resulting in the identification of several growth- and meat quality-related loci. Therefore, the newly developed chip is efficient, cost-effective, and well suited for application in local Chinese chickens, which will accelerate poultry breeding improvements and enhance conservation efforts.

pH value is a crucial index used to evaluate pork quality due to its direct impact on specific meat characteristics. This study investigated the genetic mechanisms influencing pH values through measurements taken from the longissimus dorsi muscle of Beijing Black pigs at 2 h (pH_2h) and 24 h (pH_24h) postmortem. A total of 614 Beijing Black pigs were subsequently genotyped using the Illumina Porcine 50K SNP Chip. Heritability estimates for pH_2h and pH_24h were found to be 0.19 and 0.25, respectively, with a genetic correlation of 0.53. Furthermore, we conducted both a genome-wide association study (GWAS) and an RNA sequencing (RNA-seq) analysis, the latter of which identified differentially expressed genes (DEGs) between high and low pH groups. We identified 31, 6, and 32 single-nucleotide polymorphisms in the pH_2h, pH_24h, and pH_2–24h traits, respectively. The GWAS results revealed the presence of the SYT5 gene in both the pH_2h and pH_2–24h traits, while the SNX13 gene was simultaneously identified in the pH_24h and pH_2–24h traits. The RNA-seq results also found SYT5 to be highly expressed, while SNX13 did not exhibit differential expression. Moreover, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses based on the DEGs revealed potential links between pH levels and the glycogen metabolic process as well as associations with the regulation of cell proliferation and calcium ion transmembrane transport. Ultimately, SYT5 and SNX13 emerged as key candidate genes affecting pH values at 2 and 24 h, respectively. These findings contribute to a better understanding of the genetic mechanisms affecting pork quality and safety and offer insights for enhancing meat quality through genetic improvement.

The aims of this study were to investigate the heavy metal pollution status and distribution and to analyze the relationships among metal concentrations of different links in the dairy production chain. Chromium (Cr), arsenic (As), cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) levels in water, fodder, milk, blood, hair, and feces samples collected from cows from five dairy farms in China were measured. The concentrations of Cr, As, Cd, Pb, Cu, and Zn were 4.61–11.11, 0.06–0.46, 0.17–0.29, 2.84–4.23, 4.11–7.72, and 7.23–19.91 mg/kg in silage; 12.72–40.85, 0.76–2.40, 0.05–0.16, 4.73–9.16, 44.14–78.46, and 4148.51–4845.20 μg/L in milk; 33.59–60.73, 0.09–3.57, 0.29–1.78, 20.14–39.20, 821.34–1007.45, and 2665.10–4929.95 μg/L in blood; 0.59–1.06, 0.02–0.09, 0.08–0.11, 1.70–2.09, 6.45–8.64, and 9.73–1.56 mg/kg in hair; 31.75–296.35, 0.33–5.96, 0.18–0.53, 3.35–9.06, 12.27–41.39, and 56.54–196.34 mg/kg in feces, respectively. The concentrations of heavy metals in hair were higher than those in the other samples and when combined with the results from the silage and tissue samples, we can assume that cow's hair can be used as a biological indicator for heavy metal contamination in the dairy production chain.

The objective of this study was to evaluate the impact of the determination methods (free feeding [FF] and tube feeding [TF]) on the available energy of ingredients (wheat, paddy, and brown rice). A total of 101 adult Hy-Line Brown roosters (35 weeks old) with an initial body weight of 2.72 ± 0.21 kg were used, in which 96 roosters were randomly assigned to the FF group and TF group, and the remaining five birds were selected to determine the endogenous energy loss. Each group consisted of 12 dietary treatments. In the FF group, each diet treatment comprised 2 replicates with 2 birds per replicate and 4 replicates with 1 bird per replicate for each diet in the TF group. The 12 dietary treatments included a basal diet (BD) and 11 test diets, in which wheat, paddy, and brown rice replaced 30% corn, soybean meal, and wheat bran in the BD. The experiment was performed three times. There was a significant effect of source on apparent metabolizable energy (AME) and true metabolizable energy (TME) in paddy (p < 0.05). Results showed that AME in wheat, paddy, and brown rice measured by the FF method were greater than those values gained by the TF method (p < 0.05). The average AME and TME values were 3537, 3140, and 3893 kcal/kg dry matter (DM) and 3555, 3163, and 3933 kcal/kg DM for wheat, paddy, and brown rice, respectively, measured by the FF method. The means of AME and TME evaluated by the TF method were 3270, 2988, and 3764 kcal/kg DM and 3642, 3357, and 4135 kcal/kg DM for wheat, paddy, and brown rice, respectively. In conclusion, the determination method has a considerable effect on available energy, and the TF method underestimates the AME of ingredients.

To analyze the prevalence of feline viral diseases in China, including feline panleukopenia virus (FPV), feline calicivirus (FCV), feline herpesvirus 1 (FHV-1), and feline coronavirus (FCoV) infectious diseases from 2018 to 2020, swab samples from 304 cats and serum samples from 193 cats in 18 cities were collected. The etiological investigation results of 304 cats showed that 256 (84.21%) cats were positive, infected with at least one virus, and the positive rates for FPV, FCV, FHV-1, and FCoV were 61.51%, 10.86%, 4.61%, and 55.92%, respectively. The mixed infection exhibited high complexity, and a total of eight mixed infection patterns were detected. The risk factor analysis of each pathogen in different clinical scenarios indicated that FPV positive status was significantly related to all the studied diseases, FCV positive status exhibited the most significant association with gingivostomatitis and conjunctivitis, and FHV-1 positive status was significantly related to upper respiratory tract disease, but FCoV positive status was not significantly related to any disease. Additionally, the prevalence of FPV exhibited a strong seasonality and was related to age, while the prevalence of FCV, FHV-1, and FCoV had nothing to do with season or age. FCV infection was sex related in cats, whereas the prevalence of FCV, FHV-1, and FCoV was not sex related. FPV, FCV, FHV-1, and FCoV were unrelated to breed or residential density. Antibody detection results of 193 serum samples by the virus neutralizing method indicated that the current commercial vaccines might not protect hosts against wild strains of FPV, FCV, and FHV-1 in China. In general, this study enriches epidemiological survey data of common viral diseases in cats in China and provides a theoretical basis for further development of vaccines.

This study explored the combined effects of vitamin B₁₂ and fumarate supplementation on methane (CH₄) emission and propionate synthesis in dairy cows through simulated rumen fermentation in vitro. The experimental animals were 3 cows with an average milk yield of 23 ± 2.8 kg/d, a body weight of 618 ± 100 kg, and a parity of 3 ± 1 that were selected as rumen fluid donors. The TMR diet fed to cows is a fermentation substrate. Experiments adopted 2 × 2 factorial design, including control group, vitamin group (1 mg/g DM vitamin B₁₂), fumarate group (100 mg/g DM), and combined addition group (1 mg/g DM vitamin B₁₂ and 100 mg/g DM). All treatments had no effect on the dry matter degradation (DMD). Both vitamin B₁₂ and fumarate reduced CH₄ emission, increased the propionate concentration, and reduced the acetate/propionate ratio without any observed interaction. Vitamin B₁₂ made Prevotella and Prevotellaceae_ UCG-003 increase in quantity, and fumarate increased the abundance of Succinivibrionaceae_UCG-002 and Selenomonas, both of which are propionate-producing bacteria. At the species level, the supplementation of vitamin B₁₂ and fumarate slightly changed the abundance of some strains, but it was not statistically significant. Shifts in the abundance of propionate-producing bacteria and methanogenic archaea species suggest an increase in propionate production and a decrease in CH₄ emission. In conclusion, the addition of vitamin B₁₂ and fumarate changed the fermentation mode of the rumen and reduced the emission of CH₄ by affecting the structure of the rumen microbial community, but no obvious interaction was found between the two.