农林科学最新文献

Brazil is an influential and successful food-producing country, where we can highlight artisanal cheeses gaining visibility in foreign markets. Some of these cheeses are made from raw milk, making them susceptible to contamination by microorganisms, including fungi, which can produce harmful mycotoxins. Feed contaminated with aflatoxin B1, when consumed by dairy animals, is metabolized and transformed into aflatoxin M1 (AFM1), which is excreted in milk. Therefore, the aim of this research was to investigate the occurrence of AFM1 in artisanal cheeses from two Brazilian states: Minas Gerais and São Paulo. This toxin was extracted from 10 g of sample and 50 ml pepsin solution. An aliquot of the extract was passed through an immunoaffinity column, eluted, and dried under nitrogen. For the analysis of the detection and quantification of AFM1, the High-Performance Liquid Chromatography (HPLC) fluorescence detection system was used. A total of 130 samples were analyzed; 41 tested positive for AFM1, while 89 were negative. Out of 41 positive samples, only two were above the maximum tolerated limit by ANVISA of 2.5 µg/kg. These results show the importance of investigating the occurrence of AFM1 in artisanal cheeses, aiming to prevent and increase food safety.

Pyrethroids are synthetic chemicals that account for 16% of the international insecticide market and have been shown to be of varying toxicity to different species. There are various methods available for detecting pyrethroids in agricultural products, but these products must be pre-treated to remove interference from the food matrix, such as through dispersion liquid-liquid microextraction (DLLME). This study employed two experimental design methods to optimize the continuous and discontinuous experimental parameters of DLLME and investigated whether DLLME combined with GC-NICI-MS is effective for detecting pyrethroids in agricultural products. The Taguchi design with an L9(34) orthogonal array and response surface methodology were employed to optimize the discontinuous and continuous parameters of the DLLME process, respectively. To validate the performance of GC-NICI-MS after optimized DLLME, pyrethroids in mixed standard solutions at levels ranging from 0.02 to 50.00 µg/L were measured, and the resultant calibration curves were fitted. Adequate linearity was found for the six investigated pyrethroids (r = 0.9908-0.9960). The limits of detection and quantification ranged from 0.005 to 0.035 µg/L and 0.02 to 0.1 µg/L, respectively. The proposed approach simplifies the optimization of parameters compared to reported methods and achieves considerably lower limits of detection. The concept of mixed application based on the dual experimental design method can be applied to other regulated compounds to enhance the safety of agricultural products. The feasibility of the method was confirmed by successfully detecting pyrethroids in 13 types of teas, fruit, and vegetables.

Aims: To compare the responses of liver Cu concentrations in dairy cows between three forms of injectable Cu supplementation and a negative control group.

Methods: Across two dairy farms in North Canterbury, New Zealand, 80 mid-lactation dairy cows (n = 28 and 52 per farm) were randomly allocated to four treatment groups: (a) 100-mg or (b) 200-mg dose of Cu administered as Ca Cu EDTA; (c) 75-mg dose of Cu as disodium Cu EDTA combined with Se, Zn, and Mn; or (d) no treatment (negative control). Each treatment group contained 20 cows. Groups were balanced for age, plasma Cu and pre-treatment liver Cu concentration. Blood samples and liver biopsies were collected prior to treatment. Six liver biopsies were performed on the same cow over a period of 70 days and the concentration of liver Cu was measured over time and compared to pre-treatment baseline. A mixed, multivariable, linear regression model was constructed to determine the effect of treatment on the change in liver Cu concentration compared to pre-treatment concentrations, accounting for repeated measurements taken from each cow.

Results: There was a difference in the distribution of pre-treatment liver Cu concentration between farms (p = 0.008), with medians of 1,400 (IQR 1,200-1,625) and 1,050 (IQR 805-1,425) µmol/kg on Farms 1 and 2, respectively. There was an interaction between treatment group, study day, and farm, with a treatment effect confirmed only on Farm 2. In the final model, the predicted change in liver Cu concentration (compared to pre-treatment concentrations) among cows on Farm 2 that were treated with 200 mg of Ca Cu EDTA was significantly higher than that of control cows on Days 3, 14, 28 and 42, peaking on Day 14 with a difference of 325.35 (95% CI = 97.00-554.03) µmol/kg. The study found no associations between changes in liver Cu concentration and age or prior plasma Cu concentration. The intraclass correlation coefficient was 0.57 (95% CI = 0.45-0.66), indicating the proportion of variability in changes in liver Cu concentration attributable to inter-cow variation.

Conclusions and clinical relevance: This study shows there are differences in response to injectable Cu supplementation at the farm level and wide variation in liver Cu among cows from the same farm. On one farm, a 200-mg dosage of Ca Cu EDTA significantly increased liver Cu concentration for at least 42 days.

Grape skin is a wine by-product with a high fiber and phenolic compound content, with potential application as an ingredient in food products. This work aimed to study the hedonic and sensory perception of the consumer using the Check-all-that-apply about cereal bars made with grape skin flour (GSF) obtained from wine residue. Grape skin flour with different granulometric ranges (coarse and fine) was added to the cereal bars in different proportions (10, 15, and 20%) to replace the oat flakes present in the formulation. Sensory acceptance results showed that all bars had good acceptance scores (>6.42) and presented different sensory profiles. The cereal bar containing 15% of coarse GSF had good sensory acceptance with attributes "few dark spots," "light color," and "softer," with desirable sensory characteristics and from the nutritional point of view with high fiber content and bioactive compounds and it was considered the best formulation. Therefore, the incorporation of wine by-products in cereal bars showed excellent acceptability and the possibility of insertion in the market.

Heavy metal pollution in marine organisms poses a significant threat to both ecosystems and human health. Dumping untreated sewage into the sea pollutes coastal waters with toxic metals. This study examined the levels of chromium (Cr), lead (Pb), nickel (Ni), mercury (Hg), arsenic (As) and copper (Cu) in three shrimp species of genus Penaeus i.e. Penaeus merguiensis, Penaeus monodon, and Penaeus indicus. The findings revealed that the average levels of arsenic, lead, and mercury were considerably higher than the legislative limits. Furthermore, chromium and lead levels remained consistent across shrimp species, while other metals exhibited significant variation. Additionally, THQ and HI values were below the limit of 1, indicating low health risks from consuming shrimp species from this area. However, sustained monitoring and research are essential to protect consumer health and ensure long-term sustainability of seafood resources.

Nitroimidazoles are well-known antibacterial and antiprotozoal agents, effective against various infections. However, they may also exhibit genotoxic, carcinogenic and mutagenic effects. This study aimed to develop an analytical method to quantify nitroimidazole residues and their metabolites in honey using Ultra Performance Liquid Chromatography coupled with Orbitrap High-Resolution Mass Spectrometry (UPLC-Orbitrap-HRMS) and validate it according to Commission Implementing Regulation (EU) 2021/808. The method demonstrated limits of detection (LODs) ranging from 0.01 to 0.17 µg L^-1 and limits of quantification (LOQs) from 0.020 to 0.29 µg L^-1. Recovery rates ranged from 79.8% to 104%, with relative standard deviations (RSDs) between 4.2% and 19.6%. Analysis of 96 honey samples revealed nitroimidazole residues in 18.8% of them. These findings could enhance more effectively the Egyptian monitoring programs for these compounds in honey as to improve food safety.

Integrating Artificial Intelligence (AI) through Natural Language Processing (NLP) can improve veterinary medical oncology clinical record analytics. Named Entity Recognition (NER), a critical component of NLP, can facilitate efficient data extraction and automated labelling for research and clinical decision-making. This study assesses the efficacy of the Bio-Epidemiology-NER (BioEN), an open-source NER developed using human epidemiological and medical data, on veterinary medical oncology records. The NER's performance was compared with manual annotations by a veterinary medical oncologist and a veterinary intern. Evaluation metrics included Jaccard similarity, intra-rater reliability, ROUGE scores, and standard NER performance metrics (precision, recall, F1-score). Results indicate poor direct translatability to veterinary medical oncology record text and room for improvement in the NER's performance, with precision, recall, and F1-score suggesting a marginally better alignment with the oncologist than the intern. While challenges remain, these insights contribute to the ongoing development of AI tools tailored for veterinary healthcare and highlight the need for veterinary-specific models.

Aims: To develop a colourimetric loop-mediated isothermal amplification (LAMP) assay for the detection of Pasteurella multocida in clinical poultry samples and compare the performance of this assay with PCR. A secondary aim was to evaluate a simple DNA extraction method that could enable LAMP-based testing in the field without the need for specialised laboratory equipment.

Methods: Primer sets for both LAMP and PCR were designed to amplify the KMT1 gene of P. multocida. DNA was extracted from 12 P. multocida isolates using a commercial extraction kit, and subjected to analysis using both LAMP and PCR. The analytical specificity of the LAMP assay was evaluated by testing it against a panel of 12 unrelated bacterial species, and the analytical sensitivity (limit of detection) was determined through testing of serial dilutions of the target DNA and compared to that of PCR. Subsequently, cloacal swabs (n = 40) from a commercial turkey flock were subjected to analysis using both LAMP and PCR assays, using a rapid DNA extraction method and a commercial extraction kit. Clinical sensitivity and specificity of the LAMP assay were calculated in comparison to PCR.

Results: A single DNA fragment of the expected size (∼ 200 base pairs), was amplified by PCR from 12 P. multocida isolates, which were also all positive by the LAMP assay. The identity of all PCR amplicons was confirmed by sequencing. Both PCR and LAMP showed similar analytical sensitivity, with a LOD of 20 pg of target DNA. As neither PCR nor LAMP assays produced positive results with 12 non-related bacterial species, the analytical specificity was assessed as 100%. However, LAMP demonstrated lower clinical specificity (94.74%) compared to PCR (100%) when 40 clinical samples were tested. None of the DNA samples extracted using the simplified DNA extraction method were amplified by either LAMP or PCR.

Conclusion: The LAMP assay developed in this study exhibits comparable performance to PCR in detecting P. multocida.

Clinical relevance: The use of a rapid and portable DNA extraction method, in conjunction with LAMP assays, could create opportunities for point-of-care testing for fowl cholera in field settings.

Two young walruses, recently transferred to the Vancouver Aquarium, presented with severe abrasion to their tusks. The walruses were sedated, and clinical examination and radiographs of the tusks showed that the pulp chambers were not exposed. The tips of the tusks were then prepared to receive metal crowns. Vinyl polysiloxane impressions were obtained and sent to the laboratory for chrome-nickel crown fabrication. A week later, the crowns were cemented onto the tusks and remained in place on follow-up examinations.