Dietary Shifts Research Articles

Insight into the diet of early stages of mesopelagic fishes in the Indian Ocean using DNA metabarcoding

Despite playing a critical role in oligotrophic ocean food webs, relatively little is known about the diet of mesopelagic fishes in the Indian Ocean. These fishes are an abundant component of the micronekton assemblages and are a major energy- and nutrient-rich food source, linking the plankton which they feed on to marine predators at higher trophic levels. DNA metabarcoding, a molecular method to identify species from mixed assemblages, has not been commonly used in studies of mesopelagic fish diet, but using it to analyse gut contents can greatly improve the understanding of mesopelagic fish feeding ecology. In this study, we apply DNA metabarcoding (18S rRNA and COI) to gut contents from Stomiiformes and Myctophiformes species from 20 sampling stations covering 30 ˚ of latitude on the 110 ˚ E meridian in the Indian Ocean. In total, 174 fish specimens from 13 genera were examined. Differences in the gut contents among fish families, geographic areas and fish stages were identified. Specimens within the family Myctophidae had the most diverse diet, more so in the northern sampling stations than the south. Gonostomatidae had the least diverse diet. Overall, the most frequently identified prey items from the gut contents were calanoid copepods and halocyprid ostracods. The proportion of halocyprids were also identified to be significantly different among Myctophidae larvae and juvenile specimens, which is a potential ontogenic shift in diet towards a higher ostracod contribution in juveniles as mouth gape increases. In comparison with other plankton abundance data, Copepoda were the most abundant plankton in the gut contents of all fishes sampled throughout the latitudinal gradient, allowing them to be a potential food resource through the region. There are indications that other less abundant plankton, such as like Ostracoda and Malacostraca, may be preferentially targeted by some mesopelagic fish families.

Seasonal prey taxa and size selection and drivers of age-0 walleye ontogenetic diet shifts

Prey abundance and size vary seasonally, creating a dynamic connection between predator and prey. The natural complexity related to consuming multiple prey types as fish undergo ontogenetic diet shifts combined with the frequent sampling and substantial laboratory time investment required to investigate seasonal predator-prey dynamics limits understanding of seasonal prey availability and age-0 prey taxa and size selection. Our study used frequent prey sampling spanning a four-year period to understand which prey taxa and sizes are seasonally available to age-0 walleye Sander vitreus, which were sampled from May to November across all four years of this study to document food habits and prey sizes. Consumed prey were then compared to available prey within the reservoir to evaluate prey taxa and size selection. Age-0 walleye seasonal food habits were consistently simplistic as age-0 walleye in this study largely consumed a single zooplankton taxa (calanoida) and then shifted directly to piscivory where they again focused consumption on a single taxa, and age group (age-0 gizzard shad Dorosoma cepedianum) while passing over available benthic macroinvertebrates. The ontogenetic shift to larval gizzard shad coincided with peak larval shad availability. Interestingly, age-0 walleye were size selective for both prey types, selecting the largest calanoida available when zooplanktivorous but consuming some of the smallest age-0 gizzard shad despite increasing gape size that would have allowed for consumption of larger shad.

Affordability of healthy and water-saving dietary patterns in The Gambia

Abstract Background: Dietary modification has the potential to improve nutritional status and reduce environmental impacts of the food system. However, for many countries, the optimal composition of locally contextualised healthy and sustainable diets is unknown. The Gambia is vulnerable to climate-change-induced future water scarcity which may affect crop yields and the ability to supply healthy diets. This study identifies potential shifts in Gambian diets that could make diets healthier and reduce the associated agricultural water footprint, and assesses the cost and affordability implications of such dietary changes. 
Methods: Gambian Integrated Household Survey (IHS) food consumption data was combined with market prices, food expenditure and agricultural water footprint data. Current dietary patterns were compared with WHO dietary guidelines and optimised using linear programming to identify least-cost diets that met nutrition recommendations and reduced agricultural water use. Optimisation scenarios explored the maximum reduction in green water use that could be achieved with “culturally-acceptable” dietary shifts, and the magnitude of shifts required to maintain green water use at current levels. 
Results: On average, current diets provide adequate energy and have appropriate macronutrient composition. However, only 14% of households consume enough fruit and vegetables, and consumption of added sugars exceeds recommendations. With ‘culturally-acceptable’ changes in consumption, agricultural water use could decrease by 10–13% or increase by 9%, depending on baseline dietary pattern. Extreme dietary shifts will be required to maintain water use at 2015 levels with projected population growth. To meet WHO recommendations dietary costs would increase by 43% compared to the current baseline. Healthy and green water-saving diets would require 48–63% of average household expenditure to purchase, which is unaffordable for almost half of the population. Fruit and vegetables alone account for 31–40% of the cost of optimised diets compared to 12% of current diets.
Conclusion: Dietary modification has the potential to improve the nutritional quality of Gambian diets while reducing agricultural water use, but the required changes are likely to be unaffordable for a large proportion of the population. Improving availability and affordability of nutritious foods—particularly fruit and vegetables—will be crucial for accessibility of healthy and sustainable diets in the Gambian population.

Propionic Acid Impact on Multiple Sclerosis: Evidence and Challenges.

Accumulating evidence suggests that multiple sclerosis (MS) is an environmentally influenced disorder with contributions from life-time exposure to factors including Epstein-Barr virus infection or shifts in microbiome, diet and lifestyle. One suggested factor is a deficiency in propionic acid, a short-chain fatty acid produced by gut bacteria that may contribute to the disease pathology both in animal models and in human cases of MS. Propionate appears to exert beneficial effects on the immune, peripheral and central nervous systems of people with MS (pwMS), showing immunoregulatory, neuroprotective and neurogenerative effects. These functions are crucial, given that MS is characterized by immune-mediated damage of myelin in the central nervous system. Accordingly, propionate supplementation or a modulated increase in its levels through the microbiome and diet may help counteract the pro-inflammatory state in MS by directly regulating immune system and/or by decreasing permeability of gut barrier and blood-brain barrier. This could potentially improve outcomes when used with immune-modulating therapy. However, while its broad effects are promising, further large clinical trials are necessary to evaluate its efficacy and safety in pwMS and clarify its role as a complementary therapeutic strategy. This review provides a comprehensive analysis of the evidence, challenges and limitations concerning propionic acid supplementation in MS.

Changes in social environment impact primate gut microbiota composition

BackgroundThe gut microbiota (GM) has proven to be essential for both physical health and mental wellbeing, yet the forces that ultimately shape its composition remain opaque. One critical force known to affect the GM is the social environment. Prior work in humans and free-ranging non-human primates has shown that cohabitation and frequent social interaction can lead to changes in GM composition. However, it is difficult to assess the direction of causation in these studies, and interpretations are complicated by the influence of uncontrolled but correlated factors, such as shared diet.ResultsWe performed a 15-month longitudinal investigation wherein we disentangled the impacts of diet and social living conditions on GM composition in a captive cohort of 13 male cynomolgus macaques. The animals were in single housing for the first 3 months of the study initially with a variable diet. After baseline data collection they were placed on a controlled diet for the remainder of the study. Following this diet shift the animals were moved to paired housing for 6 months, enabling enhanced social interaction, and then subsequently returned to single housing at the end of our study. This structured sequencing of diet and housing changes allowed us to assess their distinct impacts on GM composition. We found that the early dietary adjustments led to GM changes in both alpha and beta diversity, whereas changes in social living conditions only altered beta diversity. With respect to the latter, we found that two particular bacterial families — Lactobacillaceae and Clostridiaceae — demonstrated significant shifts in abundance during the transition from single housing to paired housing, which was distinct from the shifts we observed based on a change in diet. Conversely, we found that other bacteria previously associated with sociality were not altered based on changes in social living conditions but rather only by changes in diet.ConclusionsTogether, these findings decouple the influences that diet and social living have on GM composition and reconcile previous observations in the human and animal literatures. Moreover, the results indicate biological alterations of the gut that may, in part, mediate the relationship between sociality and wellbeing.

The role of gut microbiota in a generalist, golden snub-nosed monkey, adaptation to geographical diet change

Changes in diet causing ecological stress pose a significant challenge to animal survival. In response, the gut microbiota, a crucial part of the host’s digestive system, exhibits patterns of change reflective of alterations in the host’s food component. The impact of temporal dietary shifts on gut microbiota has been elucidated through multidimensional modeling of both food component and macronutrient intake. However, the broad distribution of wild generalist and the intricate complexity of their food component hinder our capacity to ascertain the degree to which their gut microbiota assist in adapting to spatial dietary variations. We examined variation in patterns of the gut microbial community according to changes in diet and in a colobine monkey with a regional variable diet, the golden snub-nosed monkey (Rhinopithecus roxellana). Specifically, we analyse the interactions between variation in food component, macronutrient intake and the gut microbial community. We compared monkeys from four populations by quantifying food component and macronutrient intake, and by sequencing 16S rRNA and the microbial macro-genomes from the faecal samples of 44 individuals. We found significant differences in the diets and gut microbial compositions, in nutrient space and macronutrient intake among some populations. Variations in gut microbiota composition across distinct populations mirror the disparities in macronutrient intake, with a notable emphasis on carbohydrate. Geographical differences in the diet among of golden snub-nosed monkey populations will result in macronutrient intake variation, with corresponding differences in macronutrient intake driving regional differences in the compositions and abundances of gut microbiota. Importantly, the gut microbiota associated with core digestive functions does not vary, with the non-core gut microbiota fluctuating in response to variation in macronutrient intake. This characteristic may enable species heavily reliant on gut microbiota for digestion to adapt to diet changes. Our results further the understanding of the roles gut microbiota play in the formation of host dietary niches.

Dietary partitioning of fishers and martens in a rapidly changing landscape

Niche partitioning is critical for the stable coexistence of competing species that share limited resources. Yet, niches are dynamic, especially in the face of rapid environmental change. Carnivores exhibit particularly strong forms of competition and are differentially affected by change. Fishers (Pekania pennanti) and martens (Martes caurina) are two species of carnivores that overlap in space, time, and resources. In the Sierra Nevada of California, these two species share habitats that are undergoing a sudden restructuring due to drought and the subsequent mortality of more than half of all trees. Using a long-term dataset from across the affected region of the Sierra Nevada, we quantified the diet, as well as dietary niche overlap and niche shift of fishers and martens during summer months before, during, and after these disturbances and as a function of spatial overlap. The summer diet of fishers and martens did not appear to be affected by change in live forest canopy and tree mortality. While fisher diet was unaffected by elevation, martens exhibited an increasing reliance on vertebrate prey at higher elevations. Our results suggest that during summer months the diet of fishers is highly diverse, even including fungi and insects, but the diet of martens is less diverse and more reliant on vertebrate prey. These different consumption patterns — which were largely unaffected by changing environmental conditions, except elevation — have led to unexpectedly low overlap in trophic niche space during the timeframe measured. Our findings demonstrate that the coexistence of martens and fishers regionally is likely facilitated, in part, through partitioning along the trophic niche axis. If drought conditions persist and lead to continued or increasingly reduced snowpack and altered vegetation, future research should assess how niche partitioning of fishers, martens, and other members of the broader carnivore community will endure.

The repatriation of wolves to Isle Royale alters the foraging of meso-carnivores

Abstract Due to the disproportionate role that large carnivores can have on communities and their global decline over the last century, carnivores are increasingly being repatriated across their historic ranges. The reintroduction of gray wolves (Canis lupus) can precipitate substantive changes to communities and ecosystems. Notably, wolves could have strong effects on smaller and subordinate carnivores, especially in altering their foraging behavior and prey selection. Past studies investigating wolf effects on other carnivores, however, have generally been conducted in relatively complex communities featuring a diverse assemblage of carnivores and prey and have lacked baseline (i.e., pre-repatriation) data. Consequently, researchers have quantified what a community looks like after wolf return, with little information on how the community behaved before. To better understand the effect of large carnivore repatriation on the foraging ecology of a carnivore community, we investigated the impact of reintroduced gray wolves on 2 meso-carnivores: Red Fox (Vulpes vulpes); and American Marten (Martes americana) within an insular and simple vertebrate community at Isle Royale National Park before and after wolf reintroduction. We analyzed >600 scats from 20 individual martens and 63 individual foxes as well as the stable isotopes of 9 and 22 tissue samples from martens and foxes, respectively, at both individual and population levels. We found that the wolf reintroduction had little effect on marten diet but strongly influenced fox diet depending on the analysis conducted. At the population level, our analysis revealed that both foxes and martens were dietary generalists consuming an array of food items including small prey, berries, and human food regardless of wolf presence. However, at the individual level, we found that prior to wolf repatriation foxes primarily consumed berries and small prey but following wolf repatriation the diet of foxes shifted to berries and human foods as well as large carrion. This post-wolf reintroduction shift in diet increased the dietary overlap between foxes and martens. Our work provides new insights into how the return of a large carnivore can alter the foraging ecology of small-bodied carnivores and act both to provision carrion resources as well drive other carnivores to consume more human food and increase dietary overlap.

Unravelling the seasonal dietary dynamics of the endangered garden dormouse (Eliomys quercinus) in Flanders, Belgium

The garden dormouse (Eliomys quercinus) faces significant population declines across Europe, prompting urgent conservation measures. A critical aspect of these efforts is understanding the species’ dietary composition and preferences within specific areas and how this changes throughout the year. We compared garden dormouse diets between two habitats in West Flanders, Belgium with faecal analysis from May to October, covering almost their entire active phase. Our findings revealed a diverse diet of both plant and animal matter, with notable variations between habitats and seasons. Blackberries and other fruits, leaves, and to a lesser extent flowers, were the predominant plant-based food sources in both study areas, with seasonal fluctuations indicating a dietary shift throughout the dormice’s active period. Spring diets consisted primarily of young leaves and flowers, changing to increased fruit consumption in summer. Beetles emerged as a main animal food source throughout the entire active period. Snails were prominently eaten in the woody area, while millipedes prevailed in the diet in the dune environment, both more in spring than later in the active season. These insights highlight the importance of maintaining diverse fruit sources and preserving beetle, snail, and millipede populations for garden dormouse conservation. This study provides valuable insights into dormouse dietary preferences and thus contributes to targeted conservation strategies being essential for the survival of the dormouse.

Exploring the Gut Microbiome's Influence on Colorectal Cancer Development and Management: A Review of Current Knowledge and Future Directions

IntroductionColorectal cancer (CRC) is a significant global health concern, ranking as the third most commonly diagnosed cancer and the second leading cause of cancer-related deaths worldwide, with over 1.9 million new cases and nearly 935,000 deaths annually. The rise in CRC incidence is attributed to various lifestyle changes, including dietary shifts, sedentary behavior, and increased obesity rates. These factors underscore the urgent need for new preventive strategies targeting the underlying mechanisms of CRC development. PurposeThis review evaluates the intricate relationship between the gut microbiome and CRC, aiming to enhance our understanding of how microbial diversity and composition contribute to CRC pathogenesis. State of Knowledge Studies reveal a correlation between the onset and progression of CRC and changes in microbial diversity and specific taxa. In CRC patients, the presence of Fusobacterium nucleatum is linked to inflammation and poor prognosis, while Bacteroides fragilis is associated with promoting colitis and carcinogenesis. The Human Microbiome Project's findings reveal that unique microbial communities can impact inflammation and tumor growth. Meta-analyses underline the crucial role of microbial diversity, influenced by diet and health status, in cancer prevention and progression, particularly in CRC. ConclusionsUnderstanding the interactions between the microbiome, diet, and host health is crucial for developing targeted treatment strategies and precision diagnostics for CRC. Insights from microbiome research could significantly improve patient outcomes in CRC management. Further high-quality studies are essential to fully elucidate the therapeutic potential of the microbiome in CRC treatment.

The distribution of environmental pressures from global dietary shift

Abstract The production and consumption of food is one of the main drivers of environmental change globally. Meanwhile, many populations remain malnourished due to insufficient or unhealthy diets. Increasingly, dietary shifts are proposed as a means to address both environmental and health concerns. We have a limited understanding of how dietary shifts could alter where food is produced and consumed and how these changes would affect the distribution of environmental pressures both globally and across different groups of people. Here we combine new food flow data linking producing to consuming country with environmental pressures to estimate how a global shift to each of four diets (Indian, EAT-Lancet, Mediterranean, and mean Food Based Dietary Guidelines (FBDGs)) could affect environmental pressures at the global, country income group, and country level. Globally, cumulative pressures decrease under the Indian, EAT-Lancet, and Mediterranean scenarios and increase under FBDGs. On average, low income countries increase their cumulative consumption and production pressures while high income countries decrease their consumption pressures, and typically decrease their production pressures. Increases in low income countries are likely due to the nutritional inadequacy of current diets and the corresponding increases in consumption quantities with a shift to our diet scenarios. Despite these increases, we believe that three out four of our simulated dietary shifts can be seen as a net benefit by decreasing global pressures while low income countries increase pressures to adequately feed their populations. Additionally, considering principles of fairness applied, some nations are more responsible for causing historical environmental pressures and should shoulder more of the change. To facilitate more equitable shifts in global diets, resources, capacity, and knowledge sharing of sustainable agricultural practices are critical to minimize the increases in pressures that low income countries would incur to adequately feed their populations.

An analysis of observed and predicted extreme heat and precipitation trends across four pulse producing regions in North America: North Dakota, Montana, Saskatchewan, and Northeastern United States

Abstract The consumption of plant-based proteins in leu of animal proteins is the most important dietary shift that would be needed to keep the world under 2 C of warming, and this shift would require a dramatic increase in the percentage of cropland devoted to nuts and pulses (Peters et al. 2016). As the demand for plant-based proteins, like pulse crops, continues to grow, it is critical to understand the impact of climate change on crop production. In this paper, we study two climate-related stressors for pulse production in North America: extreme heat and excess moisture during harvest. Pulses must be dried on the plant before harvest, requiring a 7-day dry spell before harvest or the use of Roundup (glyphosate) to kill the plants quickly. However, little is known about the changes in frequency of hot extremes or dry spells during harvest in pulse-growing regions. We analyze climate trends using the Unprecedented Simulated Extreme Ensemble (UNSEEN) method and an analysis of the Coupled Model Intercomparison Project (CMIP6) in four pulse growing regions across North America: Montana, North Dakota, Saskatchewan, and the Northeast USA. We find that temperature extremes have increased in all regions, with extreme events 3-4 times more likely today than in 1981, increasing the risk of crop loss. August and September rainfall during the harvest months has been decreasing in the Midwestern regions and it is projected to continue to decrease in the future; however, the likelihood of a wet August in the Northeast has nearly doubled. Even with this drying trend, farmers cannot assume that they will have a 7-day consecutive dry spell that would enable natural drying of pulses without synthetic drying agents like glyphosate. Future expansion of pulse production should incorporate adaptation measures to manage extreme heat and the potential for rain events during harvest.

Baleen stable isotopes reveal climate-driven behavioural shifts in North Atlantic fin whales

Climate variability impacts the structure and functioning of marine ecosystems and can trigger behavioural responses in organisms. We investigated whether such variability modulates diet and migration in the North Atlantic fin whale (Balaenoptera physalus). To reconstruct the dietary and migratory behaviours over time, we conducted stable isotope analysis of nitrogen (δ15N) and carbon (δ13C) along baleen plates from 29 fin whales sampled off southwestern (SW) Iceland in summer. We estimated a baleen growth rate of 16.1 ± 2.5 cm per year from the stable isotope oscillations observed along the baleens. We also assigned a deposition date for each baleen segment, thus obtaining isotopic sequential time series. We then assessed the potential association of these time series with the main climate patterns of the North Atlantic basin. Baleen δ15N and δ13C values are associated with the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO). During high AMO and low NAO periods, which tend to decrease krill abundance, there is an increase in both the mean and standard deviation of baleen δ15N values, suggesting that fin whales shift to higher trophic resources and expand their dietary niche. Additionally, high AMO periods, which relate to positive temperature anomalies, lead to a decrease in baleen δ13C values, suggesting that fin whales adjust their migratory routes and destinations towards higher latitudes. Significant variation in isotopic niche width between years also reflected these dietary and migratory behavioural shifts. This highlights the plasticity of the North Atlantic fin whale behaviour, a trait likely to strengthen the resilience of the species within the current context of rapid and intense climate variability.

Safefood4eu: An interdisciplinary approach on education for sustainable agri-food systems in Europe

Foods are complex products consisting of many ingredients of diverse origins. Along the food supply chains, food products are prone to spoilage and safety issues, which could give rise to different health-related concerns and outcomes. Furthermore, the existing highly centralised food systems generate substantial greenhouse gas emissions and food waste. In order to strengthen the sustainable decentralised "farm-to-fork" food chains, a mindset shift supported by relevant education and policy initiatives is highly required. The ERASMUS+ KA220 project SafeFood4EU was conceived with a crucial mission - to develop an interdisciplinary and innovative toolbox of higher education and lifelong learning courses that reflect various aspects of sustainable agri-food systems. The thematic areas discussed within the SafeFood4EU project have covered food safety and supply chain management, sustainable food systems and design, food production and quality of raw materials, food authenticity and analysis, and digital and soft skills. The main objectives have been to develop a distinctive content package and make it available to the students via an e-learning management system. The project's results, aimed at creating a pool of young and capable experts, can significantly impact future food security, thereby increasing awareness about the future challenges regarding food systems transition, dietary shift and the next generation's food security.

Impact of Forage Sources on Ruminal Bacteriome and Carcass Traits in Hanwoo Steers During the Late Fattening Stages.

This study examined the effects of different forage sources on the ruminal bacteriome, growth performance, and carcass characteristics of Hanwoo steers during the fattening stage. In Korea, where high-concentrate feeding is common, selecting suitable forage is crucial for sustainable beef production. Fifteen 23-month-old Hanwoo steers, weighing an average of 679.27 ± 43.60 kg, were fed the following five different forage sources: oat hay (OAT), rye silage (RYE), Italian ryegrass (IRS), barley forage (BAR), and rice straw silage (RSS), alongside 1.5 kg of dry matter concentrate daily for five months. Carcass traits were evaluated post-slaughter, and rumen fluid samples were analyzed using full-length 16S rRNA gene sequencing to determine the bacteriome composition. The forage source significantly affected the alpha-diversity indices and bacteriome biomarkers linked to the feed efficiency and ruminal fermentation. Differences in the backfat thickness and meat yield index were noted, with alpha-diversity indices correlating with carcass traits. The phylum Planctomycetota, especially the family Thermoguttaceae, was linked to nitrogen fixation in high-protein diets like IRS, while the genus Limimorpha emerged as a biomarker for the meat yield. These findings highlight the importance of forage selection during late fattening to optimize beef production, considering diet and bacteriome shifts.

Impact of methane and other precursor emission reductions on surface ozone in Europe: scenario analysis using the European Monitoring and Evaluation Programme (EMEP) Meteorological Synthesizing Centre – West (MSC-W) model

Abstract. The impacts of future methane (CH4) and other precursor emission changes are investigated for surface ozone (O3) in the United Nations Economic Commission for Europe (UNECE) region excluding North America and Israel (the EMEP region, for European Monitoring and Evaluation Programme) for the year 2050. The analysis includes a current legislation (CLE) and maximum feasible technical reduction (MFR) scenario, as well as a scenario that combines MFRs with an additional dietary shift that also meets the Paris Agreement objectives with respect to greenhouse gas emissions (LOW). For each scenario, background CH4 concentrations are calculated using a probabilistic Earth system model emulator and combined with other precursor emissions in a three-dimensional Eulerian chemistry-transport model. While focus is placed on peak season maximum daily 8 h average (MDA8) O3 concentrations, a range of other indicators for health and vegetation impacts are also discussed. Our analysis shows that roughly one-third of the total peak season MDA8 reduction achieved between the 2050 CLE and MFR scenarios is attributable to CH4 reductions, resulting predominantly from CH4 emission reductions outside of the EMEP region. The impact of other precursor emission reductions is split nearly evenly between the reductions inside and outside of the EMEP region. However, the relative importance of CH4 and other precursor emission reductions is shown to depend on the choice of O3 indicator, though indicators sensitive to peak O3 show generally consistent results. The analysis also highlights the synergistic impacts of CH4 mitigation as reducing solely CH4 achieves, beyond air quality improvement, nearly two-thirds of the total global warming reduction calculated for the LOW scenario compared to the CLE case.

Population Genomics of Adaptive Radiations: Exceptionally High Levels of Genetic Diversity and Recombination in an Endemic Spider From the Canary Islands.

The spider genus Dysdera has undergone a remarkable diversification in the oceanic archipelago of the Canary Islands, with ~60 endemic species having originated during the 20 million years since the origin of the archipelago. This evolutionary radiation has been accompanied by substantial dietary shifts, often characterised by phenotypic modifications encompassing morphological, metabolic and behavioural changes. Hence, these endemic spiders represent an excellent model for understanding the evolutionary drivers and to pinpoint the genomic determinants underlying adaptive radiations. Recently, we achieved the first chromosome-level genome assembly of one of the endemic species, D. silvatica, providing a high-quality reference sequence for evolutionary genomics studies. Here, we conducted a low coverage-based resequencing study of a natural population of D. silvatica from La Gomera island. Taking advantage of the new high-quality genome, we characterised genome-wide levels of nucleotide polymorphism, divergence and linkage disequilibrium, and inferred the demographic history of this population. We also performed comprehensive genome-wide scans for recent positive selection. Our findings uncovered exceptionally high levels of nucleotide diversity and recombination in this geographically restricted endemic species, indicative of large historical effective population sizes. We also identified several candidate genomic regions that are potentially under positive selection, highlighting relevant biological processes, such as vision and nitrogen extraction as potential adaptation targets. These processes may ultimately drive species diversification in this genus. This pioneering study of spiders that are endemic to an oceanic archipelago lays the groundwork for broader population genomics analyses aimed at understanding the genetic mechanisms driving adaptive radiation in island ecosystems.

Sea cucumbers and their symbiotic microbiome have evolved to feed on seabed sediments

Sea cucumbers are predominant deposit feeders in benthic ecosystems, providing protective benefits to coral reefs by reducing disease prevalence. However, how they receive sufficient nutrition from seabed sediments remains poorly understood. Here, we investigate Holothuria leucospilota, an ecologically significant tropical sea cucumber, to elucidate digestive mechanisms underlying marine deposit-feeding. Genomic analysis reveals intriguing evolutionary adaptation characterized by an expansion of digestive carbohydrase genes and a contraction of digestive protease genes, suggesting specialization in digesting microalgae. Developmentally, two pivotal dietary shifts, namely, from endogenous nutrition to planktonic feeding, and from planktonic feeding to deposit feeding, induce changes in digestive tract enzyme profiles, with adults mainly expressing carbohydrases and lipases. A nuanced symbiotic relationship exists between gut microbiota and the host, namely, specific resident bacteria supply crucial enzymes for food digestion, while other bacteria are digested and provide assimilable nutrients. Our study further identifies Holothuroidea lineage-specific lysozymes that are restrictedly expressed in the intestines to support bacterial digestion. Overall, this work advances our knowledge of the evolutionary innovations in the sea cucumber digestive system which enable them to efficiently utilize nutrients from seabed sediments and promote food recycling within marine ecosystems.

Lactiplantibacillus argentoratensis AGMB00912 alleviates diarrhea and promotes the growth performance of piglets during the weaning transition

BackgroundPreventing post-weaning diarrhea (PWD) in weaned piglets is a crucial challenge in the swine production industry. The stress of weaning, dietary shifts from maternal milk to solid feed, and environmental changes lead to decreased microbial diversity, increased pathogen abundance, and compromised intestinal integrity. We have previously identified Lactiplantibacillus argentoratensis AGMB00912 (LA) in healthy porcine feces, which demonstrated antimicrobial activity against pathogens and enhanced short-chain fatty acid production. This research aimed to evaluate the efficacy of LA strain supplementation as a strategy to inhibit PWD and enhance overall growth performance in weaned piglets.ResultsLA supplementation in weaned piglets significantly increased body weight gain, average daily gain, and average daily feed intake. It also alleviated diarrhea symptoms (diarrhea score and incidence). Notably, LA was found to enrich beneficial microbial populations (Lactobacillus, Anaerobutyricum, Roseburia, Lachnospiraceae, and Blautia) while reducing the abundance of harmful bacteria (Helicobacter and Campylobacter). This not only reduces the direct impact of pathogens but also improves the overall gut microbiota structure, thus enhancing the resilience of weaned piglets. LA treatment also promotes the growth of the small intestinal epithelial structure, strengthens gut barrier integrity, and increases short-chain fatty acid levels in the gut.ConclusionsThe study findings demonstrate the promising potential of LA in preventing PWD. Supplementation with the LA strain offers a promising feed additive for improving intestinal health and growth in piglets during the weaning transition, with the potential to significantly reduce the incidence and severity of PWD.

Gradual behaviour change towards meat reduction revisited: Applying the decisional balance scale in a Dutch study

Meat moderation is needed to mitigate climate change and to address issues related to animal welfare and public health. Yet little is known on the process that consumers go through towards meat-reduced diets. Strässner and Hartmann (2023) recently developed the decisional balance scale (DB scale) for meat reduction, in order to get a better understanding of the trade-offs that consumers encounter in this dietary shift. The current study sets out to replicate their German study in the Dutch context. A survey has been conducted among a representative sample of Dutch adults (N = 1982). Overall, the present study corroborated Strässner and Hartmann's findings. Similar to the German situation, Legitimation is the most important barrier, and the Downsides of factory farming is the most important motivator for meat reduction in the Netherlands. The present study extends the German study by comparing the DB scale with other established scales in research on meat reduction. Although several motivational elements related to the legitimacy of eating meat, health impact and production of meat appear in different instruments, the DB scale sets itself apart in adding practical elements (feasibility). Finally, the insights in the decision balance of population subgroups at different stages of behaviour change (no intention, intention, performing) showed that the further in the meat reduction process, the more the pros outweigh the cons. With this, the current study provides valuable insights in bolstering consumers in meat moderation. Our findings support the idea of a gradual shift and reveal that there is potential for acceleration in behaviour change towards meat reduction to be found in adjusting the self-evidence of high-intensity livestock farming systems and the meat-centric food consumption culture.