Results 2025

Abstract: This study investigated the impact of microplastics (MPs) in animal feed on rumen activity and concentrate degradability using lamb rumen fluid in vitro. Three types of MPs—polyethylene terephthalate (PET), low-density polyethylene (LDPE), and polyamide (PA)—were tested at contamination levels of 0%, 0.6%, 1.2%, and 1.8% of dry matter. Results showed that MPs significantly disrupted rumen fermentation dynamics and reduced feed degradability. MPs contamination increased gas production, accelerated fermentation rates, and shortened the lag time before gas production (p < 0.05). Additionally, MPs impaired microbial efficiency, increased ammonia-nitrogen (NH₃-N) levels, decreased rumen protozoa populations, and reduced concentrate degradability (p < 0.05). LDPE exhibited the most severe effects, causing the highest increases in gas production and NH₃-N levels (15% and 12%, respectively at LDPE highest dose) while decreasing microbial efficiency, protozoa count, and feed degradability (16.0%, 16.4%, and 4.5%, respectively at LDPE highest dose). The severity of MPs' impacts followed a significant linear trend, with higher concentrations leading to more pronounced negative effects. The findings highlight MPs as significant emerging pollutants that can adversely affect rumen function and animal nutrition.

Simple Summary: Microplastics are becoming an increasing environmental concern in farm animals. This study presents the first in vitro investigation of the effects of lowdensity polyethylene microplastic contamination on rumen fermentation dynamics and

feed utilization in a simulated ruminal digestive system. Concentrate feed was incubated in buffered rumen fluid collected from lambs, supplemented with low-density polyethylene microplastics and compared to the concentrate incubated in the buffered rumen fluid without microplastic addition. The results indicated that low-density polyethylene microplastics reduced the ability of the lamb rumen to ferment feed, which led to a reduction in metabolizable energy of the concentrate feed. Additionally, this contaminant decreased the number of rumen protozoa and the ammonia levels. These findings underscore the potential risks posed by low-density polyethylene microplastics in ruminant nutrition.

Abstract: The increasing frequency of extreme weather events, exacerbated by climate change, has caused significant physical damage to crops worldwide. This study explores the potential of repurposing crop plants that exhibit structural breakage due to hailstorms and strong winds and were originally cultivated for seed production (amaranth, borage, camelina, flax, quinoa, soybean, and white lupin) as alternative forages for ruminants.

Their nutritional value was assessed by analyzing chemical composition, in vitro dry matter degradability (DMD), in vitro neutral detergent fiber degradability (NDFD), estimated dry matter intake (DMI), and relative feed value (RFV) compared to conventional forages (alfalfa and ryegrass hay from undamaged plant). Results revealed significant variability among the damaged crops. Borage, amaranth, and white lupin exhibited superior DMD, NDFD, estimated DMI, and RFV, positioning them as promising forage alternatives. Soybean and quinoa showed protein content, DMD, NDFD, estimated DMI, and RFV comparable to alfalfa hay, suggesting their suitability as substitutes. However, camelina exhibited limited NDFD, while flax had low DMD, NDFD, estimated DMI, and RFV, indicating the

need for pre-treatment strategies to optimize their nutritional value. Overall, repurposing weather-damaged borage, amaranth, white lupin, soybean, and quinoa as alternative forages for ruminants provides a promising approach to mitigating feed shortages, improving feed resource utilization, and optimizing resource utilization in livestock production.

Simple Summary: The blackberry is an invasive plant that spreads rapidly, harming native species and fragile ecosystems. Controlling its growth is a challenge, but using grazing livestock like goats could be an effective solution. This study explored how the quality and digestibility of blackberry leaves change with the seasons and at different altitudes in the Northwestern Italian Alps. Leaves were collected from areas accessible to goats during all four seasons and at three heights above sea level: low, medium, and high. The results showed that blackberry leaves can be a nutritious, affordable feed option for goats, offering high protein and fiber content. However, goats struggle to break down the fiber effectively. Spring leaves were the most nutritious, with higher protein levels and better digestibility, while winter leaves from higher altitudes were easier to digest due to lower lignin levels. These findings highlight the potential of blackberry leaves in goat diets and emphasize the importance of planning grazing based on seasonal and altitude-related changes. This approach could benefit farmers by reducing feed costs and helping manage invasive plants while protecting the environment.

ABSTRACT: Ruminants play a crucial role in the food chain, but are also considered contributors of green-house gas (GHG) emissions . Essential oils (EOs) are emerging as natural feed additives in rumi-nants’ nutrition to enhance animal health, performance and reduce environmental footprint.Among EOs, lemongrass (Cymbopogon winterianus) and oregano (Origanum vulgare) EOs (LEOand OEO) have attracted attention as modulators of ruminal fermentations, but their role needsto be clarified. The experiment was designed using a randomised setup to assess the effects ofLEO and OEO on in vitro ruminal fermentation and GHGs, using total mixed ration (TMR) as sub-strate (incubation time 24h). Experimental treatments included (doses as % of TMR on DMbasis): 1) control only TMR (0% EOs) 2) 0.07% LEO 3) 0.07% OEO 4) 0.035% LEO þ 0.035% OEO5) 0.07% LEO þ 0.07% OEO. Each treatment was repeated three times in two experimental runs.Only EO combinations reduced total gas (−9%, p¼0.001). All EOs decreased CO2 emissions by−5 to −12% with no significant differences between treatments (p<0.001), although anti-meth-anogenic effects were not observed (p¼0.192). Volatile fatty acids were slightly affected only byEOs blend at the highest dose, resulting in a reduction of propionate (−1.3%, p¼0.02), anincrease in acetate:propionate (þ0.16%, p¼0.04) and isovalerate (þ0.7%, p¼0.03). LEO reducedpH (−0.6%, p¼0.004), while OEO increased oxidation capacity (þ4.2%, p¼0.004), but bothparameters remained within physiological ranges. Canonical discriminant analysis confirmed dis-tinct EOs effects, highlighting their potential as natural additives for improving ruminal fermen-tation and mitigating ruminant environmental footprint. 

Microplastic (MPs) feed contamination represents a significant risk to the entire food chain, with potential human exposure as MPs can cross intestinal barriers, enter the bloodstream, or accumulate in animal-derived products [1,2]. Currently, no real-time methods exist that are simple, rapid, and reliable for detecting MPs in animal feed. This study evaluates the potential of Near-Infrared Spectroscopy (NIRS) as a tool for detecting and quantifying MPs in animal feed under field conditions, without MP extraction process.

Two types of MPs - white polystyrene (PS) and black low-density polyethylene (LDPE) - were used to contaminate corn silage at different concentrations (0, 0.5, 1, 3, 5, 10, and 50.0 mg/g dry matter - DM). MPs of varying sizes were obtained by grinding plastic pieces (< 5mm). A total of 13 grinded corn silage samples (6+6+1) were scanned 6 times each, with 4 scans per session, resulting in 312 spectra. Scanning was performed using the Aurora portable NIR spectrometer (GraiNit S.r.l., Italy) across a spectral range of 950–1650 nm. Calibration models were built using 70% of the dataset and validated on the remaining 30%, using Ucal™ (Unity Scientific, Australia) and grouping the dataset by PS, LDPE and their combination (PS+LDPE). The Standard Normal Variate pre-processing method combined with detrend was applied to five different chemometric approaches: PLS, PLS+PCA, PCR, MLR+PLS, and MLR+PCA [3]. Models were assessed by calculating the coefficient of determinations (R²), Standard Error of Calibration (SEC) and Prediction (SEP), Mean Absolute Error (MAE), the distribution of the residuals and power prediction (PP).

The PLS+PCA showed the best results for each MP type. LDPE exhibited an excellent calibration fit (R²=0.93, using 11 factors) and a good validation fit (R²=0.89). The standard errors were low and consistent (SEC=4.62 mg/g DM, SEP=5.22 mg/g DM), and the MAE were very low (1.9×10-6 mg/g DM and 0.3 mg/g DM, respectively), though calibration residuals showed a non-normal distribution. PS also showed a good fitting calibration (R²=0.92, 12 factors) but slightly lower prediction performance (R²=0.85), with a higher SEP (6.3 mg/g DM) compared to SEC (4.5 mg/g). The MAEs remained however low (2.7×10-7 mg/g DM in calibration and 0.40 mg/g DM in validation) but the residual distribution was non-normal in the validation phase. The model for the prediction of the contamination by PS+LDPE MPs showed the weakest performance, with a fair calibration fitting (R²=0.89, 14 factors) but a quite lower prediction fit (R²=0.75). Both the standard errors (SEC=5.7 mg/g DM and SEP=8.9 mg/g DM) and MAE (5. ×10-7 mg/g DM in calibration and 1.5 mg/g DM in validation) were higher than those observed for the models developed per single MP type. The three models showed a good PP, always higher than 3.0.

Concluding, portable NIRS effectively detect MP contamination in animal feed, with the PLS+PCA model showing the best results, especially for LDPE. The findings underscore the possibility of analysing individual MPs (PS and LDPE), as this approach yields better predictive performance compared to combined models (PS+LDPE) and the portable NIRS can be a promising tool for the real-time monitoring directly MPs in corn silage without extraction.

[1] N. Beriot, J. Peek, R. Zornoza, V. Geissen, and E. H. Lwanga. “Low density-microplastics detected in sheep faeces and soil: A case study from the intensive vegetable farming in Southeast Spain”. Science of the Total Environment, 2021, 755, 142653. https://doi.org/10.1016/j.scitotenv.2020.142653

[2] I. van der Veen, L. M. van Mourik, M. J. M. van Velzen, Q. R. Groenewoud, and H. A. Leslie. "Plastic particles in livestock feed, milk, meat and blood". 2022, https://www.plasticsoupfoundation.org/wp-content/uploads/2022/07/Livestock-mps-study-KEYmessages_final_2022-07-05.pdf

[3] P. Berzaghi., and R. Riovanto. “Near infrared spectroscopy in animal science production: principles and applications”. Italian Journal of Animal Science, 2009, 8( sup3), 39–62. htts://doi.org/10.4081/ijas.2009.s3.39

Microplastic (MP) pollution is a growing concern that affects habitats and species, contaminating all matrices. Additionally, plastic additives and chemical pollutants linked to MPs may have toxic effects on species.

Currently, only few studies investigating the presence of MPs in farmed animals and their products, and research about the transmission of MPs from livestock products to humans is just at the early stage. Different studies have shown that MPs can accumulate in the digestive systems of some animals, causing inflammation, stress, and possible disruptions in nutrient absorption. MPs have been found in milk, meat, and other animal-derived products, raising food safety concerns. Therefore, scientists emphasize the need for further research to assess the risks. 

MP contamination in milk were detected in raw and processed milk, likely originating from contaminated feed, water, and plastic packaging. Livestock can ingest MPs through contaminated feed and water leading to potential health implications for animals and human consumers. Additionally, processing equipment and plastic containers may contribute to further contamination. 

The aim of this study is to find a valid method for MPs separation and characterisation in milk, following the product from milking to packaging to mitigate the impact of MPs in livestock farming.

Milk samples were collected from farm to supermarket, observing different problematics depending on the fat presence, especially in raw milk. Major problematics regarded the milk filtration, due to the presence of fats. Heating the milk at different temperatures and the use of KOH 10% can partially solve these problems, helping in milk filtration. Different filters were tested too, highlighting the need of high porosity for raw milk. Both microscopic and spectroscopic techniques can be useful to count and characterize MPs on filter. The use of UV light can help in MP identification, especially for small and clear particles. Blank samples and the filtration of chemicals and distilled water used is essential to avoid MP contamination during all step, from sampling to microscopic and spectroscopic analysis.

Further studies are necessary to assess the full impact of MPs in milk and potential risks to consumers. Addressing MP contamination in livestock farming is crucial for protecting both animal and human health. Collaborative efforts between policymakers, researchers, and farmers are necessary for developing sustainable solutions, and reduce plastic in agriculture and food production.

The increasing accumulation of microplastics (MPs) in agricultural systems poses a significant threat to the digestive efficiency in ruminants. This study investigated the effects of adding polyethylene terephthalate (PET) MPs at concentrations of 5 and 10 g/L in buffer-ruminal gastrointestinal solutions on ruminal degradability, gastrointestinal digestibility of rumen-undegraded residue, and total tract digestibility of corn silage and mixed hay using an in vitro model.

Results showed that at the highest PET MP concentration (10 g/L), crude protein degradability decreased by 9% for corn silage and 8% for mixed hay. A reduction in neutral detergent fiber degradability was observed exclusively in mixed hay at the highest PET MP concentrations, with a decrease of 5%. Dry matter and acid detergent fiber degradability remained unaffected. In the gastrointestinal phase, crude protein digestibility of rumen-undegraded residue was reduced by 9% in mixed hay at the lowest PET MP concentration (5 g/L), while dry matter digestibility of rumen-undegraded residue remained unchanged. The total digestibility of crude protein in mixed hay decreased by 5% at both PET MP levels, while for corn silage, it decreased by 3% only at the highest PET MP concentration. Total dry matter digestibility remained unaffected.

These findings demonstrate that PET MPs are not inert within the ruminant digestive system and can impair digestive efficiency, with more significant effects observed in mixed hay. 

Near InfraRed Spectroscopy (NIRS) is commonly employed in agriculture for bromatological and rapid analyses. This study introduces a novel approach discovered through an unexpected error, which uncovered a hidden potential to enhance the NIR spectroscopic estimation of microplastic (MPs) content in two feeds of vastly different compositions. The method leverages "occluded" radiation, referring to the radiation detected by the instrument even when the shutter is closed. This observation was successfully replicated on additional samples using the same equipment, prompting us to share these results. In this study, we present a comparative analysis of two spectral datasets (Opened and Occluded shutter) consisting of 60 spectra - half Total Mixed Ration, and half Hay - across three different levels of green low-density polyethylene MPs (0.0, 0.1, and 0.3%). 

The samples were analyzed in reflectance mode using a benchmark IdentiCheck™ FT-NIR-IR system (PE, Perkin-Elmer, Beaconsfield, England), covering the 714-3333 nm range with 2751 absorbance points, as described in [1]. Each absorbance spectrum was the average of 26 scans, with each sample being mixed and replicated 10 times. Each sample was first measured with the visible laser beam, followed immediately by a measurement with the shutter occluded to prevent direct reflection. The sample was then randomly repositioned, and this measurement procedure was repeated. The absorbance spectra were imported into GRAMS/AI™ 7.02 software (Win-ISI III, Infrasoft International, Port Matilda, PA, USA) and processed using the modified Partial Least Squares method, both as raw data, after standardization and first or second derivative transformations. Model stability was evaluated through cross-validation, which allowed for the removal of outliers exceeding the critical values of ‘T-Student’ = 2.5 and ‘Global H’ = 10. The Standard Error of Cross Validation (SECV) and the Ratio of Performance to Deviation (RPD) were used as performance indicators.

The absorbance value (Log 1/R) obtained from the open shutter was 0.211 ± 0.398 (N=165060). In contrast, the occluded absorbance signal, diffused from the closed shutter, was significantly lower at 0.014 ± 0.384 - 93% lower than the open signal, though still greater than zero (P<0.0001). The correlograms comparing concentration vs NIR spectra showed distinct differences between open and occluded shutter: low and constant correlation in the open mode, and high and highly variable in the occluded mode. Accuracy (SECV) were 0.2% in closed mode vs 0.6% in open mode, with RPD values of 5.5 and 2.2, respectively. For comparison, Corradini et al. [2] for LDPE reported an accuracy of 0.8% for soil.

The phenomenon of detecting occluded/ghost radiation is likely the result of a combination of the optical properties of the sample, the sensitivity of the FT-NIR-IR instrument, and the specific way light interacts with the feed materials and microplastics. The closed shutter may allow some radiation to still be detected due to scattering, internal reflections, and the material properties of the feed. This results in a weak, but measurable, signal that could be used to enhance the detection of microplastics in feeds, even when they are not immediately visible in the sample. The ability to replicate this observation across different samples further suggests that this phenomenon is a consistent and reliable feature that could improve NIRS-based analysis.

[1] S. Tassone, G. Masoero, and P.G. Peiretti, “Vibrational spectroscopy to predict in vitro digestibility and the maturity index of different forage crops during the growing cycle and after freeze- or oven-drying treatment,” Anim. Feed Sci. and Tech., vol. 194, pp. 12-15, 2014.

[2] F. Corradini, H. Bartholomeus, E.H. Lwanga, H. Gertsen, H., and V. Geissen, “Predicting soil microplastic concentration using vis-NIR spectroscopy,” Sci. Tot. Env., vol. 650, pp.922-932, 2019.