Differences In Diet Composition Research Articles

The influence of chronotype on temporal patterns of eating and diet composition in shift and non-shift workers

When and what you eat can be linked to circadian preference (i.e., chronotype) and occupation (e.g., shift worker). Evening chronotypes, with a later circadian preference, tend to have meals later, distribute energy intake toward the end of the day(1), and more unhealthy eating habits than morning chronotypes(2); whereas night shift work is associated with later mealtimes and poor diet quality as a result of circadian disruption due to their work(3). What is unclear is whether chronotype influences the occupation-induced dietary patterns observed in shift workers. This study aimed to investigate associations between chronotype, temporal patterns of eating and diet composition in shift and non-shift workers. Adults from shift (SW) and non-shift (N-SW) populations were recruited. A Chrononutrition Questionnaire captured chronotype, duration of eating window (DEW), time of first eating occasion (FEO) and last eating occasion (LEO) while diet composition (energy, protein, total fat, saturated fat, carbohydrate, fibre, alcohol) was extracted from 7-day food diaries. Associations between chronotype and DEW/FEO/LEO, and between DEW/FEO/LEO and diet composition were determined by Spearman Rank Coefficients. 95 participants were enrolled (N-SW: n = 39; SW: n = 56); predominantly female (71%), morning chronotype (37%), on average 40.46 ± 15.08 years with BMI of 27.04 ± 5.77kg/m2. 84 returned food diaries. Later chronotype was positively associated with later times of FEO (N-SW: r = ,50, SW: r = ,69) and LEO (N-SW: r = ,63, SW: r = ,54) on free (non-work) days (p≤.002), and longer DEW (r = ,42) and later LEO (r = ,60) on workdays for non-shift workers (p<.01). However, there were no significant differences in diet composition by day/shift type between chronotypes across the study population. On afternoon shifts, longer DEW was associated with greater energy (r = ,60) and total fat intake (r = ,60) and later LEO with greater alcohol intake (r = ,59) (p<.05). On night shifts, a longer DEW was associated with lower alcohol intake (r=-.45, p<.05). Amongst non-shift workers, later FEO was associated with lower fibre intake on workdays (r=-.58, p<.001). Additionally, non-shift workers who were later chronotypes had later LEO, which on workdays associated with lower fibre (r=-.45) and alcohol intake (r=-.43); and on work-free days, associated with lower alcohol intake (r=-.45) (p<.05). Not surprisingly, evening chronotypes across the study population had longer and/or later eating windows on work-free days (i.e., free of constraints), as did non-shift workers on workdays, while the influence of chronotype on DEW, FEO, and LEO across shifts were less clear. Hence, for shift workers, occupation appeared to be a greater driver of temporal eating patterns than chronotype. Additionally, later eating times of evening chronotypes was not associated with negative diet composition. The exception was lower fibre intake amongst non-shift workers; but regardless of chronotype, shift workers may benefit from having a shorter and earlier DEW on afternoon shifts to minimise energy, fat, and alcohol intake.

Chick diet in UK Little Terns Sternula albifrons

ABSTRACT Capsule We studied the diet of Little Tern chicks in the UK using new data collected as part of the EU LIFE-funded Little Tern Recovery Project (2014–2018) (the LIFE Project), which shows that, despite a wide variety of prey items being recorded, diet at UK colonies is dominated by two types of lipid-rich marine fish: sandeel Ammodytes spp. and clupeid species (Atlantic Herring Clupea harengus and European Sprat Sprattus sprattus). Aims To analyse data on the diet of Little Tern chicks from the LIFE Project and assess what additional insight these provide in comparison to the findings in previous literature. Methods Timed chick-feeding observations were made at 12 English and Welsh Little Tern colonies between 2014 and 2018 and compared to descriptions of chick diet from other UK studies (published and unpublished). Results Chick diet data from the LIFE Project were dominated by lipid-rich marine fish, principally sandeels and clupeid species (82% of all recorded prey items). Adult Little Terns feeding chicks with crustaceans or other invertebrates were recorded at 75% of colonies, but there was no evidence that these routinely made up a substantial proportion of chick diet. We found no significant inter-annual differences in diet composition between individual colonies. However, analysis of records of chick diet over a longer time series (Long Nanny colony in Northumberland, with data available for 17 of the years between 1998 and 2018) showed some significant differences in diet composition between years. Conclusion Although Little Terns are generalist feeders, 82% of the prey diet consisted of two prey types: sandeels and clupeids. This may leave existing UK Little Tern colonies vulnerable to any future climate change impacts affecting either the distribution or nutritional quality of their main prey species.

Resource partitioning in a novel herbivore assemblage in South America.

Human-induced species declines and extinctions have led to the downsizing of large-herbivore assemblages, with implications for many ecosystem processes. Active reintroduction of extirpated large herbivores or their functional equivalents may help to reverse this trend and restore diverse ecosystems and their processes. However, it is unclear whether resource competition between native and non-native herbivores could threaten restoration initiatives, or to what extent (re)introduced species may influence local vegetation dynamics. To answer these questions, we investigated the diets of a novel South American herbivore assemblage that includes resident native species, reintroduced native species and introduced non-native species. We examined plant composition, diet breadth and the overlap between species to describe the local herbivory profile and the potential for resource competition. Using DNA metabarcoding on faecal samples (n = 465), we analysed the diets of the herbivore assemblage in the Rincón del Socorro rewilding area of Iberá National Park, Argentina. We compared the species richness of faecal samples, the occurrence of plant families/growth forms and the compositional similarity of samples (inter- and intraspecifically). Our results indicate species-level taxonomic partitioning of plant resources by herbivores in this system. Differences in sample richness, composition and diet breadth reflected a diverse range of herbivory strategies, from grazers (capybara) to mixed feeders/browsers (brocket deer, lowland tapir). Differences in diet compositional similarity (Jaccard) revealed strong taxonomic resource partitioning. The two herbivores with the most similar diets (Pampas deer and brocket deer) still differed by more than 80%. Furthermore, all but one species (axis deer) had more similar diet composition intraspecifically than compared to the others. Overall, we found little evidence for resource competition between herbivore species. Instead, recently reintroduced native species and historically introduced non-natives are likely expanding the range of herbivory dynamics in the ecosystem. Further research will be needed to determine the full ecological impacts of these (re)introduced herbivores. In conclusion, we show clear differences in diet breadth and composition among native, reintroduced and non-native herbivore species that may be key to promoting resource partitioning, species coexistence and the restoration of ecological function.

Dynamics of Gut Bacteria Across Different Zooplankton Genera in the Baltic Sea

In aquatic ecosystems, zooplankton-associated bacteria potentially have a great impact on the structure of ecosystems and trophic networks by providing various metabolic pathways and altering the ecological niche of host species. To understand the composition and drivers of zooplankton gut microbiota, we investigated the associated microbial communities of four zooplankton genera from different seasons in the Baltic Sea using the 16S rRNA gene. Among the 143 ASVs (amplified sequence variants) observed belonging to heterotrophic bacteria, 28 ASVs were shared across all zooplankton hosts over the season, and these shared core ASVs represented more than 25% and up to 60% of relative abundance in zooplankton hosts but were present at low relative abundance in the filtered water. Zooplankton host identity had stronger effects on bacterial composition than seasonal variation, with the composition of gut bacterial communities showing host-specific clustering patterns. Although bacterial compositions and dominating core bacteria were different between zooplankton hosts, higher gut bacteria diversity and more bacteria contributing to the temporal variation were found in Temora and Pseudocalanus, compared to Acartia and Synchaeta. Diet diatom and filamentous cyanobacteria negatively correlated with gut bacteria diversity, but the difference in diet composition did not explain the dissimilarity of gut bacteria composition, suggesting a general effect of diet on the inner conditions in the zooplankton gut. Synchaeta maintained high stability of gut bacterial communities with unexpectedly low bacteria-bacteria interactions as compared to the copepods, indicating host-specific regulation traits. Our results suggest that the patterns of gut bacteria dynamics are host-specific and the variability of gut bacteria is not only related to host taxonomy but also related to host behavior and life history traits.

Fecal DNA metabarcoding reveals seasonal and annual variation in willow ptarmigan diet.

Understanding spatio-temporal variation in the diet of alpine herbivores is important to predict how a changing climate will affect these species in the future. We examined the spatio-temporal variation in willow ptarmigan (Lagopus l. lagopus) diet using DNA metabarcoding of fecal pellets sampled from winter to early summer over three consecutive years. Furthermore, we assessed how snow cover and vegetation phenology affected diet variation. We also investigated sex differences in diet composition. We identified 18 important diet taxa and the genera Betula, Vaccinium and Empetrum occurred most frequently. Diet composition and richness varied within and between years. Seasonally, there was a shift from a narrow winter diet dominated by trees and dwarf shrubs to a broader spring diet with more nutritious field vegetation. This seasonal progression differed among years. The temporal variation in diet was better explained by day of year than by snow cover and vegetation phenology. Females had a more diverse diet than males, but there were no sex differences in diet composition. Our results demonstrate that metabarcoding of fecal samples provides the opportunity to assess factors affecting diet composition of species in alpine ecosystems in the context of a changing climate.

Feeding habits of Pacific anchovy, Engraulis japonicus (Actinopterygii: Clupeiformes: Engraulidae), captured off the southern coasts of Korea

Understanding the feeding ecology of anchovies in the southern waters of Korea is crucial for improving ecosystem management. However, to date, few studies have examined seasonal changes in the diet of Pacific anchovy, Engraulis japonicus Temminck et Schlegel, 1846, in Korean waters, with the majority of these focusing on the larval and adult stages. The presently reported study provides updates on the feeding habits of E. japonicus off the southern coast of Korea. We analyzed 347 individuals. One-way analysis of similarity was performed to evaluate the differences in diet composition among size classes and seasons of E. japonicus, and correspondence analysis was conducted using the matrix of the percentage by number (%N) data for prey with occurrence of less than 10% to determine the distribution of prey across all size classes and each season. The diet of E. japonicus was investigated according to season and four size classes. The fork length of these specimens ranged from 5.4 to 14.1 cm. A total of 55 prey taxa of varying sizes between 0.33 mm (diatom Coscinodiscus spp.) and 5.8 mm (fish larvae) were recorded. Anchovies were exclusively planktivorous, and copepods were the most common prey, comprising 82.1% of the identified food items and 84.3% of anchovy stomach contents analyzed. However, their occurrence and abundance varied according to season and Pacific anchovy size class. According to the percentage of the index of relative importance (%IRI), the most important prey items were the copepods Calanus sinicus (48.0%), Paracalanus orientalis (31.7%), bivalve larvae (5.8%), Ditrichocorycaeus affinis (4.2%), and calanoid copepods (2.4%). Analysis of similarities and similarity percentage analysis indicated that a distinct diet of Pacific anchovy in the southern waters of Korea is potentially driven by differences in hydrological conditions. Correspondence analysis revealed that anchovies had the most significant impact on the differences between size classes. The results deepen our understanding of prey species diversity and intraspecific food competition off the southern coast of Korea.

Ketogenic diet for epilepsy and obesity: Is it the same?

The term “ketogenic diet” (KD) is used for a wide variety of diets with diverse indications ranging from obesity to neurological diseases, as if it was the same diet. This terminology is confusing for patients and the medical and scientific community. The term “ketogenic” diet implies a dietary regimen characterized by increased levels of circulating ketone bodies that should be measured in blood (beta-hydroxybutyrate), urine (acetoacetate) or breath (acetone) to verify the “ketogenic metabolic condition”. Our viewpoint highlights that KDs used for epilepsy and obesity are not the same; the protocols aimed at weight loss characterized by low-fat, low-CHO and moderate/high protein content are not ketogenic by themselves but may become mildly ketogenic when high calorie restriction is applied. In contrast, there are standardized protocols for neurological diseases treatment for which ketosis has been established to be part of the mechanism of action. Therefore, in our opinion, the term ketogenic dietary therapy (KDT) should be reserved to the protocols considered for epilepsy and other neurological diseases, as suggested by the International Study Group in 2018. We propose to adjust the abbreviations in VLCHKD for Very Low CarboHydrate Ketogenic Diet and VLEKD for Very Low Energy Ketogenic Diet, to clarify the differences in dietary composition. We recommend that investigators describe the researchers describing efficacy or side effects of KDs, to clearly specify the dietary protocol used with its unique acronym and level of ketosis, when ketosis is considered as a component of the diet's mechanism of action.

The impact of ketogenic diet on some metabolic and non-metabolic diseases: Evidence from human and animal model experiments.

The ketogenic diet (KD) is recognized as minimum carbohydrate and maximum fat intakes, which leads to ketosis stimulation, a state that is thought to metabolize fat more than carbohydrates for energy supply. KD has gained more interest in recent years and is for many purposes, including weight loss and managing serious diseases like type 2 diabetes. On the other hand, many believe that KD has safety issues and are uncertain about the health drawbacks. Thus, the outcomes of the effect of KD on metabolic and non-metabolic disease remain disputable. The current narrative review aims to evaluate the effect of KD on several diseases concerning the human health. To our best knowledge, the first report aims to investigate the efficacy of KD on multiple human health issues including type 2 diabetes and weight loss, cardiovascular disease, kidney failure and hypertension, non-alcoholic fatty liver, mental problem, oral health, libido, and osteoporosis. The literature searches were performed in Databases, PubMed, Scopus, and web of Science looking for both animal and human model designs. The results heterogeneity seems to be explained by differences in diet composition and duration. Also, the available findings may show that proper control of carbohydrates, a significant reduction in glycemic control and glycated hemoglobin, and weight loss by KD can be an approach to improve diabetes and obesity, hypertension, non-alcoholic fatty liver, PCOS, libido, oral health, and mental problem if isocaloric is considered. However, for some other diseases like cardiovascular disease and osteoporosis, more robust data are needed. Therefore, there is robust data to support the notion that KD can be effective for some metabolic and non-metabolic diseases but not for all of them. So they have to be followed cautiously and under the supervision of health professionals.

Diet composition of a native fish species in a neotropical lentic environment

Native species are important to the dynamics of aquatic environments. Studies that seek to understand the basic biology of these species provide information on the species and the dynamics of the natural environment. We characterized the diet, feeding habits, and trophic niche breadth of the native species Hoplosternum littorale (Hancock, 1828) in neotropical lentic environments. Collections were carried out in July 2018 at two sampling points (lagoons) located in the São Francisco Falso River and the Corvo River using gill nets. Stomach content was analyzed, and food items were separated, identified, and quantified using the volumetric method. PERMANOVA analysis was performed to evaluate possible differences in diet between the lagoons. Furthermore, PERMDISP was used to test the trophic niche breadth. Fifteen food items were recorded in the São Francisco lagoon, with the most consumed items being detritus, Diptera (larvae and pupa), and Odonata (nymph). Seven food items were recorded in the Corvo lagoon, with detritus being the most consumed. There was no difference in diet composition and trophic niche breadth between the evaluated lagoons. For both lagoons studied, the species was determined to be a detritivore feeding habit, given its diet's predominant consumption of detritus. The detritivore classification may be related to environmental conditions, food availability, and functional morphology. We also observed the presence of microplastics in the stomachs of some specimens, demonstrating anthropic influence on aquatic environments. Our study contributes to bettering knowledge on this species, and consequently the conservation of the species. It can also serve as a basis for conducting future scientific studies, along with developing the area of study related to Brazilian fish ecology.

Diet affects the growth and behavior of Argiope bruennichi spiders and correlates with the species richness of their vertically and horizontally transmitted tissue-resident bacteria

The ability to spread and build quality webs is crucial to spider survival. These abilities may differ in response to dietary adjustments and changes in assemblages of tissue-resident bacteria, including vertically transmitted endosymbiotic taxa, particularly when expanding outside the native ranges. We measured the physical and behavioral parameters of the invasive wasp spider Argiope bruennichi subjected to four types of diets, including protein-rich and lipid-rich diets. We used 16S rDNA sequencing to evaluate vertically and horizontally transmitted tissue-resident bacteria, including endosymbionts, in the cephalothorax and legs of the tested spiders. The diet composition affected the body weight and carapace length as well as the locomotor parameters but not the orb-weaving abilities. Dietary treatments led to changes in the diversity and operational taxonomic unit (OTU) richness of facultative and obligate tissue endosymbionts, with Wolbachia and Rickettsia having higher relative abundance in spiders fed a lipid-rich diet. The higher OTU richness of facultative and obligate endosymbionts was associated with better locomotor performance. The other tissue-resident microbes were dominated by Firmicutes; the dominance and diversity of tissue-resident microbiomes also differed among spiders treated with different diets. The highest alpha diversity of tissue-resident microbes was present in spiders fed the standard diet, whereas all other diets led to a decrease in alpha diversity and various changes at the level of individual genera and OTUs. In conclusion, the tissues of A. bruennichi host tremendously diverse assemblages of bacteria, including obligate or facultative endosymbionts, which are sensitive to differences in diet composition and affect the locomotion of their hosts.

Parity and nutrient total-tract digestibility in dairy cows during transition period

Cows experience many physiological, nutritional and social changes during transition period. This study aims to evaluate the differences in nutrients total-tract digestibility (nTTD) between primiparous (PP) and multiparous (MP) cows through the transition period. From -23, -5, 0, 7, 14, and 30 days from calving a sample of feed and feces samples were collected from 25 Holstein cows (11 PP and 14 MP) as well as daily rumination time through accelerometers.The results show that average nTTD were different (p ≤ 0.02) for amylase-treated neutral detergent fiber organic matter (aNDFom) and potentially digestible neutral detergent fiber (pdNDF240; 52.5 vs. 54.0 and 78.8 vs. 81.3, respectively in PP vs. MP), while no differences were found regarding pdNDF24 and starch (88.5 vs. 88.6 and 95.1 vs. 96.1, respectively in PP vs. MP). Total-tract starch digestibility (TTstarchD) was different among timepoints (p < 0.01), going from an average of 91.40 up to 97.39% of starch, on times -23 and 14, respectively. Differences in total-tract digestibility of aNDFom among timepoints (p < 0.01) was expected because of differences in diet composition among lactating and non-lactating cows. No differences in daily rumination time (p = 0.92), TTstarchD and total-tract potentially digestible NDF digestibility at 24 h (TTpdNDF24D) were recorded. Our findings show that fiber digestibility during the transition period is higher in MP probably for a different ruminal retention time. These differences should be considered when formulating rations for groups with different parity number.

Seasonal variation in trophic structure and community niche dynamics of an Arctic coastal community of marine vertebrates

Temporal variation in food web structure is widespread among highly seasonal environments, such as the Arctic, and is driven by changes in resource availability. Variation in resource availability can lead to species differences in diet composition, isotopic niche width, and trophic position (TP) across seasons. Here, we used tissue samples that represent two distinct turnover rates for diet (liver = shorter term, muscle = longer term) from 18 fish and three marine mammal species to investigate seasonal (i) variation in TPs within the Southampton Island marine ecosystem of Hudson Bay, (ii) variation in consumer isotopic niche width within this part of the food web, and (iii) variation in community niche dynamics among a fish and marine mammal community using stable carbon (δ13C) and nitrogen (δ15N) isotope analyses. Many zooplanktivores and piscivores increased in TP in summer (i.e., shorter-term turnover period), whereas benthic feeders dependent on ice-obligate prey decreased in TP. Most isotopic niche widths and community metrics (δ15N range, total ellipse area, mean centroid distance) were higher in liver than muscle. Our findings demonstrate seasonal changes in TPs, which suggests that Arctic communities may be differentially affected by longer ice-free periods and earlier onset of primary production due to accelerated climate change.

Diet Analysis of the Amur Sleeper (Perccottus glenii) from the Danube River Drainage Channel (Serbia)

The stomach content of 277 Amur sleeper individuals has been analyzed to present its feeding habits. Fish were sampled using electrofishing from July to November 2017 in the Danube River drainage channel near Veliko Gradište (Serbia). Fish age was estimated by otoliths examination. Ingested prey organisms were identified to the lowest reliable taxonomic level. The biotic indices: vacuity index (VI), frequency of occurrence (F), abundance (Cn), index of importance (PV), Shannon`s diversity index (H`), and equitability index (Eh) were calculated. A total of 18 prey categories and 1144 individual prey were identified in the fish diet, dominantly aquatic macroinvertebrates. There were no significant difference in diet composition between sampling months as well as 0+, 1+, and 2+ age groups (both 3+ and 4+ had one individual). Only eight individuals were found with empty intestines, thus VI was low (2.9). In average, each fish had 4.1 prey items in their intestines. For whole sample, H′ was 1.84 and Eh was 0.64. Trichoptera, Ephemeroptera, and Gastropoda were the most frequent, dominant, and abundant. The greatest diversity of prey items was recorded for fish sampled in October as well as for 2+ individuals, and the lowest for fish from August and 0+ individuals.

Aphidophagous predators in commercial Capsicum cultivars and characterization of their trophic network using stomach content analysis

AbstractViruses and aphids, the most recent vectors of viruses (Hemiptera: Aphididae) of the genera Myzus and Aphis, are the main phytosanitary problems of Capsicum spp. (Solanales: Solanaceae) agricultural systems in Colombia. The incorporation of biological control in integrated pest management (IPM) programmes, which can be used to reduce aphid populations in solanaceous crops, is hampered by the lack of information on the natural enemy community, such as parasitoids, predators and generalist aphidophagous. For this reason, the objective of this research was to determine and characterize the community of generalist aphidophagous (Coccinellidae and Syrphidae) in the cultivation of chilli pepper in south‐western Colombia, and to characterize their diet through stomach content analysis using next‐generation sequencing (NGS) techniques. Two species of Coccinellidae and one species of Syrphidae were the most abundant predators in commercial crops of Capsicum spp. and fed preferentially on aphids that attacked the pepper plants. The characterization of the diet of these predators using molecular tools revealed intraspecific predation, secondary predation of aphid parasitoids and consumption of alternative prey to the aphids attacking the pepper plants. Differences in diet composition were observed between larval and adult coccinellids, and between coccinellids and the hoverfly species studied. The results suggest that dominant predators may be suitable for use in IPM programmes to control aphids in pepper crops, as their diet consists mainly of aphids that attack pepper plants. In addition, these predators can take advantage of the agricultural matrix by feeding on alternative prey in the absence of aphids.

Diet composition, niche overlap and partitioning of five sympatric rhinolophid bats in Southwestern China during summer

Understanding trophic niche differentiation is critical for exploring interspecific competition and stable coexistence among morphologically similar sympatric species. Bats are an ideal model for studying trophic niche differentiation among species because of their high taxonomic and ecological diversities, as well as their special life history traits. Although many factors can affect bat trophic niches, few studies have combined multiple factors to investigate the influences on bat trophic niches. In this study, we analyzed the summer diet and potential influencing factors of five sympatric rhinolophid bats in southwestern China: Rhinolophus macrotis, Rhinolophus osgoodi, Rhinolophus ferrumequinum, Rhinolophus affinis, and Rhinolophus pusillus. All five species mainly fed on Lepidopteran and Dipteran insects, with a large trophic niche breadth for each species and a low degree of dietary overlap. With the exception of R. affinis and R. pusillus, significant differences in diet composition were detected among species, which indicated relatively low interspecific competition. Canonical correspondence analysis showed that both echolocation calls and body size significantly affected interspecific diet differentiation, while wing morphology and bite force had relatively weak effects. This study suggests that the combined effects of multiple factors may drive trophic niche differentiation among five rhinolophid bat species in the study area.

Density‐dependent processes and population dynamics of native sculpin in a mountain river

AbstractUnderstanding the processes governing population dynamics is important for effective conservation and environmental management. Disentangling the relative role of density‐dependent versus density‐independent processes on population dynamics is often made difficult by the inability to control for abiotic or biotic factors, but long‐term datasets are invaluable in this pursuit. We used a 14‐year dataset from the Logan River, Utah, to assess long‐term trends in abundance and evidence of density‐dependent and density‐independent effects on population dynamics of Paiute sculpin (Cottus beldingii) across six sites. Additionally, we evaluated the feeding ecology of sculpin over 4 years. Sculpin densities generally increased from upstream to downstream, and the annual per capita rate of increase was negatively and significantly correlated with sculpin density at four of six sites. We observed a negative relationship between total gut content and sculpin density but did not observe a negative relationship between relative condition and density. Sculpin displayed a generalist feeding strategy, and interannual differences in diet composition appeared to be influenced by interannual differences in flow, particularly years with higher magnitude flow. The observed spatial patterns in sculpin abundance throughout the watershed matched those of invasive brown trout (Salmo trutta), the top piscivore in the Logan River, and likely represent affinities for the suite of ecological conditions associated with downstream sections of the Logan River. Our results suggest that sculpin populations are regulated largely by density‐dependent processes and match those from other studies on sculpin population dynamics including a range of species and habitats that differ vastly in abiotic conditions.

Relative abundance and size composition of prey in the common minke whale diet in selected areas of the northeastern Atlantic during 2000-04

A total of 210 common minke whales (Balaenoptera acutorostrata) were sampled in five different areas in the northeastern Atlantic during May-June 2000-04. Analysis of forestomach contents revealed a relatively mixed diet at the population level, whereas on an individual level, each whale had fed upon mainly one species. There were significant differences in diet composition between areas and some differences between years. The importance of krill in the Barents Sea increased with latitude and krill dominated the Spitsbergen diet. Capelin dominated the diet around Bear Island and contributed considerably to the diet along the coast of northern Norway. In the latter area, herring and haddock were also a great part of the diet. The diet in the Norwegian Sea consisted of mainly mature herring, while the diet in the North Sea was dominated by sand eels and mackerel. The minke whales were found to feed on a wide range of prey sizes, apparently determined by the availability of different size classes.

Similar breeding performance despite inter-annual differences in diet composition of seabirds inhabiting a tropical environment

Amidst unprecedented anthropogenic pressure on marine ecosystems, seabirds can serve as sentinels for shifts in marine prey availability. We examined the diet and foraging ecology of 2 sympatric Procellariiformes, the Cape Verde shearwater Calonectris edwardsii and Bulwer’s petrel Bulweria bulwerii, during their breeding period in Cabo Verde, West Africa. By analysing fatty acids (FAs), δ15N and δ13C values, and using GPS loggers, we quantitatively assessed the diet of both adults and chicks, estimated the isotopic niche of adult birds, and identified their main foraging regions. Our findings revealed annual variations in the diet of both adults and chicks, supported by quantitative prey estimates and FA signatures. Adult Cape Verde shearwaters consistently displayed a diet enriched in commercial fishes (&gt;40%), with varying proportions of squid or non-commercial fishes across different years. Bulwer’s petrel displayed greater diet variability, consuming higher proportions of squid (54%), mesopelagic fishes (81%), and commercial fishes (29%) in 2017, 2018, and 2019, respectively. Chicks of both species exhibited varying diets across years. However, chick growth and fledging parameters remained fairly consistent among years. The isotopic niche, GPS tracking, and oceanographic conditions within foraging regions provided partial support for the annual variations observed in the diet of adults, especially for Cape Verde shearwaters. However, the diet differences for Bulwer’s petrels were less straightforward, likely due to the equitable distribution of their main prey. Notably, both species exhibited resilience in coping with unfavourable foraging conditions, enabling adult breeders to exploit a wide variety of prey resources without compromising breeding outcomes.

Do cage fish farms interfere with the food aspects of the wild species Metynnis lippincottianus (Characiformes, Serrasalmidae)?

We evaluated the differences in the diet and trophic guild of Metynnis lippincottianus under the influence of cage fish farms in the Neotropical reservoir. We collected samples from two areas (cage farm and control) in March and June 2019. Stomach contents were examined, and food items were identified and quantified using the volumetric method. Differences in diet composition were evaluated using PERMANOVA and SIMPER analyses, while trophic niche breadth was determined using PERMDISP. The trophic guild for each area was also determined. Significant differences in diet between cage farm and control areas were observed, due to consumption of pelleted feed, microcrustaceans, Egeria sp., and filamentous algae. In both sampling areas, M. lippincottianus was classified as algivorous. Despite the pelleted feed consumption in the cage farm area, no differences were observed in trophic niche breadth and the trophic guild. In addition, algae and macrophytes still accounted for the majority of this species' diet in both areas, indicating partitioning of resources. This resource partitioning may favor coexistence, but it is worth mentioning that pelleted feed consumption still indicates the influence of cage fish farms on the diet of wild fish.

DIET COMPOSITION, CONDITION FACTOR AND INTESTINAL COEFFICIENT OF THE FISH Astyanax lineatus REFLECT THE ANTHROPOGENIC EFFECTS ON STREAMS IN CENTRAL BRAZIL

Human activities, such as urbanization, can cause instability in the aquatic biota. This instability can modify aquatic food resource availability, consequently shifting the diet composition of fish. Because the diet consumed by fish closely affects the anatomy of their digestive tract, it can also alter their intestinal coefficient. In this study, we analyzed the diet composition, condition factor and intestinal coefficient of Astyanax lineatus (Perugia, 1891) from two distinct habitats: a “degraded habitat” (Cabaça stream) in a reserve inside the city perimeter and a “preserved habitat” (Salobra River) in Mato Grosso do Sul State, Central Brazil. We found a total of 15 food items, all of which were found in the urban stream, with a predominance of detritus and Chironomidae larvae, and six in the natural area, with a predominance of plant remains. There was a distinct difference in diet composition between fishes in the two areas ( p &lt; 0.05, PERMANOVA); however, there was no significant difference in inter-individual variability. The most frequent food items were detritus in the “degraded habitat”, while in the “preserved habitat” plant and insect remains were most frequent. The relative condition factor measured by the fish's length-weight relationship was not significantly different between the two habitats. The intestinal coefficient was significantly different between the individuals from each habitat, and it was longer in fish from the natural habitat. Therefore, even though A. lineatus is known to be a generalist species, its feeding plasticity depends on the ecological integrity of the two types of habitats.