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Effect of applying crust-freezing after skin-packaging on the natural microflora of Atlantic salmon (Salmo salar) during storage at low temperatures
Get PDFpeer-reviewedThe aim of the present study was to evaluate the effect of crust-freezing (CF) on fresh salmon fillets in skin-packaging during storage at −2.0°C. After CF, all treated samples and untreated controls were stored in a refrigerated cabinet for 20 d. Sampling was carried out at days 0, 2, 6, 8, 10, 14 and 20 in order to analyse total volatile basic nitrogen (TVB-N) and levels of mesophilic and psychrophilic viable counts (MVC and PVC). Enterobacteriaceae (ENT), lactic acid bacteria (LAB), H2S-producing bacteria (SPB) and Pseudomonas spp. (PSE). No significant differences in TVB-N were found between samples except for those taken on day 20 where TVB-N levels of CF samples were lower than controls. Our results suggest that ENT might be the limiting microbial group to determine the end of shelf-life. Thus, if this group is used as an indicator of acceptability, the shelf-life of salmon can be extended from 8 to 20 d when skin-packed and then treated with CF
Ecological value of different vegetated strip types in providing valuable insect-rich habitats for grey partridge chicks
Get PDFpeer-reviewedThe intensification and specialisation of agriculture has contributed to farmland wildlife decline, including farmland birds. Grey partridge is a farmland species which has experienced a significant decline across Europe in recent decades. Chick survival rate is a key determinant of grey partridge population change and depends essentially on the availability of insect food. In this study, ground-dwelling and canopy-dwelling insects were collected using pitfall trapping and sweep netting methodologies, respectively, on different strip types in an area established for the conservation of grey partridge. The aim was to further our understanding of the value of different vegetated strip types in providing insect-rich habitats for grey partridge chicks. Overall, wildflower strip (WS) provided the greatest insect abundance. Significantly more ground-dwelling insects were found on WS, natural regeneration (NS) and leguminous strips (LS) than on grass strip (GS). Canopy-dwelling insects were also significantly more abundant on WS compared to all other strip types. This study highlights that WSs may represent important habitats in providing insect-rich food for grey partridge chicks and sowing these strips may therefore play a key role in decreasing chick mortality and supporting grey partridge conservation. It also demonstrates that other different vegetated strip types may still provide strip-specific insect taxa, in addition to other valuable resources. This study recommends a complex mosaic of different strip types to provide key resources for grey partridge, such as insect and plant food, nesting habitats and overwinter cover
Short communication: Genotype-phenotype association analysis revealed different utilization ability of 2'-fucosyllactose in Bifidobacterium genus
Get PDFpeer-reviewedThe oligosaccharide 2'-fucosyllactose (2'FL) in human breast milk selectively promotes the proliferation of bifidobacteria. One hundred fifty-one Bifidobacterium strains were evaluated for their capacity to utilize 2'FL based on the combination of phenotype and genotype association analysis. Through genotype analysis, 37 strains were predicted to have the ability to use 2'FL, including Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium longum ssp. longum, Bifidobacterium longum ssp. infantis, and Bifidobacterium dentium, whereas Bifidobacterium adolescentis, Bifidobacterium animalis, Bifidobacterium pseudocatenulatum, and Bifidobacterium angulatum could not use 2'FL. For in vitro utilization, there were noteworthy differences for 2'FL usage among different species, which were 100% consistent with genotype prediction. The results indicated that 2'FL utilization ability differed even within the same species, and Bifidobacterium followed the currently well-known pathway to utilize 2'FL, which could provide guidance to develop personalized prebiotics for different bifidobacteria via gene-trait matching analysis
The simulated environmental impact of incorporating white clover into pasture-based dairy production systems
Get PDFpeer-reviewedWhite clover (WC) offers an alternative source of nitrogen (N) for pasture-based systems. Substituting energy- and carbon-intensive synthetic N fertilizers with N derived from biological fixation by WC has been highlighted as a promising environmental mitigation strategy through the omission of emissions, pollutants, and energy usage during the production and application of synthetic fertilizer. Therefore, the objective was to investigate the effect of the inclusion of WC in perennial ryegrass (PRG) swards on the environmental impact of pasture-based dairy systems. Cradle-to-farm gate life cycle assessment of 3 pasture-based dairy systems were conducted: (1) a PRG–WC sward receiving 150 kg of N/ha per year (CL150), (2) a PRG–WC sward receiving 250 kg of N/ha per year (CL250), and (3) a PRG-only sward receiving 250 kg of N/ha per year (GR250). A dairy environmental model was updated with country-specific N excretion equations and recently developed N2O, NH3, and NO3− emission factors. The environmental impact categories assessed were global warming potential, nonrenewable energy, acidification potential, and eutrophication potential (marine and freshwater). Impact categories were expressed using 2 functional units: per hectare and per metric tonne of fat- and protein-corrected milk. The GR250 system had the lowest milk production and highest global warming potential, nonrenewable energy, and acidification potential per tonne of fat- and protein-corrected milk for all systems. The CL250 system produced the most milk and had the highest environmental impact across all categories when expressed on an area basis. It also had the highest marine eutrophication potential for both functional units. The impact category freshwater eutrophication potential did not differ across the 3 systems. The CL150 system had the lowest environmental impact across all categories and functional units. This life cycle assessment study demonstrates that the substitution of synthetic N fertilizer with atmospheric N fixed by WC has potential to reduce the environmental impact of intensive pasture-based dairy systems in temperate regions, not only through improvement in animal performance but also through the reduction in total emissions and pollutants contributing to the environmental indicators assessed
Effects of substrate stress and light intensity on enhanced biological phosphorus removal in a photo-activated sludge system
Get PDFpeer-reviewedPhoto-activated sludge (PAS) systems are an emerging wastewater treatment technology where microalgae provide oxygen to bacteria without the need for external aeration. There is limited knowledge on the optimal conditions for enhanced biological phosphorus removal (EBPR) in systems containing a mixture of polyphosphate accumulating organisms (PAOs) and microalgae. This research aimed to study the effects of substrate composition and light intensity on the performance of a laboratory-scale EBPR-PAS system. Initially, a model-based design was developed to study the effect of organic carbon (COD), inorganic carbon (HCO3) and ammonium-nitrogen (NH4-N) in nitrification deprived conditions on phosphorus (P) removal. Based on the mathematical model, two different synthetic wastewater compositions (COD:HCO3:NH4-N: 10:20:1 and 10:10:4) were examined at a light intensity of 350 µmol m−2 sec−1. Add to this, the performance of the system was also investigated at light intensities: 87.5, 175, and 262.5 µmol m−2 sec−1 for short terms. Results showed that wastewater having a high level of HCO3 and low level of NH4-N (ratio of 10:20:1) favored only microalgal growth, and had poor P removal due to a shortage of NH4-N for PAOs growth. However, lowering the HCO3 level and increasing the NH4-N level (ratio of 10:10:4) balanced PAOs and microalgae symbiosis, and had a positive influence on P removal. Under this mode of operation, the system was able to operate without external aeration and achieved a net P removal of 10.33 ±1.45 mg L−1 at an influent COD of 100 mg L−1. No significant variation was observed in the reactor performance for different light intensities, indicating the EBPR-PAS system can be operated at low light intensities with a positive influence on P removal.Nuffi
Field scale estimates of soil carbon stocks on ten heavy textured farms across Ireland
Get PDFpeer-reviewedThe world's soils store vast amounts (≈2,500 GT) of Carbon which acts as a vital sink to counterbalance the effects of increasing atmospheric carbon dioxide. There have been fruitful efforts to quantify soil Carbon stocks at national scales, which are required for policy level decisions but lack the high resolution required to support farm specific decisions. It is hypothesised that farm scale evaluations of soils can provide insight that is masked in national scale studies and can allow for spatially explicit management approaches to optimise soil Carbon storage and sequestration, such that it can be prioritized within profitable production systems. The objective of the present study was to estimate Carbon stocks on a range of heavy textured soils at field and farm scale and to quantify Carbon storage relative to national scale estimates. Ten grassland dairy farms (mean area of 52.2 Ha) were surveyed, sampled and classified to determine soil types and quantify soil Carbon stores. The level of Carbon present (mean: 346.0 T/Ha) at these sites was greater than previous averages on such soils quantified at national scale (by a factor of 1.1–3.9 depending on soil type). Furthermore, if Carbon saturation potential was realised, the amount of Carbon stored could be increased by an average of 792.1 T/Ha in each profile (from 346.0 to 1138.1 T/Ha). Current management has fostered the retention of large stores of soil Carbon on such soils/farms which co-exist within highly productive farm systems. As there is a societal demand to retain and enhance soil carbon stores to mitigate climate change, high Carbon soils should be identified and, under appropriate policies, commodified to offer a direct incentive to retain soil Carbon. The value of this resource should be recognised and polices to ensure a spatially explicit approach for soil Carbon management should be adopted
High-fat diet alters stress behavior, inflammatory parameters and gut microbiota in Tg APP mice in a sex-specific manner
Get PDFpeer-reviewedLong-term high-fat diet (HFD) consumption commonly leads to obesity, a major health concern of western societies and a risk factor for Alzheimer's disease (AD). Both conditions present glial activation and inflammation and show sex differences in their incidence, clinical manifestation, and disease course. HFD intake has an important impact on gut microbiota, the bacteria present in the gut, and microbiota dysbiosis is associated with inflammation and certain mental disorders such as anxiety. In this study, we have analyzed the effects of a prolonged (18 weeks, starting at 7 months of age) HFD on male and female mice, both wild type (WT) and TgAPP mice, a model for AD, investigating the behavioral profile, gut microbiota composition and inflammatory/phagocytosis-related gene expression in hippocampus. In the open-field test, no overt differences in motor activity were observed between male and female or WT and TgAPP mice on a low-fat diet (LFD). However, HFD induced anxiety, as judged by decreased motor activity and increased time in the margins in the open-field, and a trend towards increased immobility time in the tail suspension test, with increased defecation. Intriguingly, female TgAPP mice on HFD showed less immobility and defecation compared to female WT mice on HFD. HFD induced dysbiosis of gut microbiota, resulting in reduced microbiota diversity and abundance compared with LFD fed mice, with some significant differences due to sex and little effect of genotype. Gene expression of pro-inflammatory/phagocytic markers in the hippocampus were not different between male and female WT mice, and in TgAPP mice of both sexes, some cytokines (IL-6 and IFNγ) were higher than in WT mice on LFD, more so in female TgAPP (IL-6). HFD induced few alterations in mRNA expression of inflammatory/phagocytosis-related genes in male mice, whether WT (IL-1β, MHCII), or TgAPP (IL-6). However, in female TgAPP, altered gene expression returned towards control levels following prolonged HFD (IL-6, IL-12β, TNFα, CD36, IRAK4, PYRY6). In summary, we demonstrate that HFD induces anxiogenic symptoms, marked alterations in gut microbiota, and increased expression of inflammatory genes, except for female TgAPP that appear to be resistant to the diet effects. Lifestyle interventions should be introduced to prevent AD onset or exacerbation by reducing inflammation and its associated symptoms; however, our results suggest that the eventual goal of developing prevention and treatment strategies should take sex into consideration
Influence of molecular weight fractionation on the antimicrobial and anticancer properties of a fucoidan rich-extract from the macroalgae Fucus vesiculosus
Get PDFpeer-reviewedThe objective of this study was to investigate the antimicrobial and anticancer properties of a fucoidan extract and subsequent fractions isolated from the macroalgae Fucus vesiculosus. The fractions obtained (>300 kDa, 300 kDa fraction presented the lowest IC50 values (0.052% - 24 h; 0.032% - 6 days). The potential bioactivity of fucoidan as an antimicrobial and anticancer agent was demonstrated in this study. Hence, the related mechanisms of action should be explored in a near future
Microbial Quality of Liquid Feed for Pigs and Its Impact on the Porcine Gut Microbiome
Get PDFpeer-reviewedThere is evidence that spontaneous fermentation frequently occurs in liquid pig feed that is intended to be delivered as fresh liquid feed, often with a resultant deterioration in the microbial and nutritional quality of the feed, which can negatively affect pig health and growth. Strategies including controlled fermentation with microbial inoculants, pre-fermentation or soaking of the cereal fraction of the diet, enzyme supplementation and dietary acidification have been employed to inhibit pathogens and prevent deterioration of feed nutritional quality, with promising results obtained in many cases. This review evaluates the impact of these strategies on the microbial quality of liquid feed and discusses how they can be further improved. It also investigates if/how these strategies impact the pig gut microbiota and growth performance of liquid-fed pigs. Finally, we review liquid feed system sanitisation practices, which are highly variable from farm to farm and discuss the impact of these practices and whether they are beneficial or detrimental to liquid feed microbial quality. Overall, we provide a comprehensive review of the current state of knowledge on liquid feed for pigs, focusing on factors affecting microbial quality and strategies for its optimisation, as well as its impact on the pig gut microbiome
Linoleic acid induces different metabolic modes in two Bifidobacterium breve strains with different conjugated linoleic acid-producing abilities
Get PDFpeer-reviewedFrequently, Bifidobacterium breve strains are found to be CLA-producers. Previous studies revealed that free linoleic acid inhibited the growth of bifidobacterial strains, however, the reason why bifidobacteria with different CLA-producing abilities exhibit similar adaptive modes to linoleic acid (LA) stress is still unknown. We used B. breve strains CCFM683 and CCFM1025, which exhibit 85% and 0% CLA conversion rates, respectively, together with metabonomics analyses, to elucidate the putative factors involved in the protection against LA stress. We found that the pathways involved in amino acid, carbohydrate, and fatty acid metabolisms were much more active in B. breve CCFM1025. Moreover, l-cysteine, l-methionine, mannitol, and 18-hydroxy-oleate accumulated to a much higher level in B. breve CCFM1025, probably providing primary protection. In particular, the levels of several antioxidant compounds, including l-ascorbate, glutathione, ubiquinol-6, 3-demethylubiquinol-7, and demethylmenaquinol-7, were much higher in B. breve CCFM1025, suggesting that these antioxidants may provide a primary protective effect to the strain without CLA-producing abilities