Natural Diet Research Articles

Timing of outdoor light exposure is associated with sleep-wake consolidation in community-dwelling older men

IntroductionA consolidated sleep-wake pattern is essential for maintaining healthy cognition in older individuals, but many suffer from sleep fragmentation that exacerbates age-related cognitive decline and worsens overall mental and physical health. Timed light exposure (light therapy) has been explored as a countermeasure, but mixed results have been obtained. To determine whether the timing of light exposure is important for sleep-wake consolidation, we analyzed the natural light diets of a cohort of community-dwelling older men.MethodsThe degree of sleep-wake fragmentation and light exposure patterns were obtained over a week using wrist actigraphy. Correlations between fragmentation, light patterns, and various physical and mental health measures were examined (n = 877).ResultsOur findings revealed that higher sleep-wake fragmentation correlated with poorer physical and mental health and reduced cognition. Moreover, reduced daytime light exposure was associated with increased sleep-wake fragmentation. Interestingly, morning and evening light exposure (>1,000 lux) were not useful in distinguishing between low and high sleep-wake fragmentation scores, while increased afternoon light exposure showed much better discrimination. Specifically, optimal discrimination between low and high fragmentation occurred 6.7 h after habitual sleep offset. This suggests that afternoon light therapy might be more efficient in consolidating sleep and wake in older adults, particularly in those with low-amplitude circadian rhythms.DiscussionThis study highlights the significance of properly-timed light exposure in promoting consolidated sleep and cognitive health among older individuals. Tailored light-based strategies may have the potential to enhance physical, mental, and cognitive well-being in the aging population.

Atlantic cod individual spatial behaviour and stable isotope associations in a no-take marine reserve.

Foraging is a behavioural process and, therefore, individual behaviour and diet are theorized to covary. However, few comparisons of individual behaviour type and diet exist in the wild. We tested whether behaviour type and diet covary in a protected population of Atlantic cod, Gadus morhua. Working in a no-take marine reserve, we could collect data on natural behavioural variation and diet choice with minimal anthropogenic disturbance. We inferred behaviour using acoustic telemetry and diet from stable isotope compositions (expressed as δ13 C and δ15 N values). We further investigated whether behaviour and diet could have survival costs. We found cod with shorter diel vertical migration distances fed at higher trophic levels. Cod δ13 C and δ15 N values scaled positively with body size. Neither behaviour nor diet predicted survival, indicating phenotypic diversity is maintained without survival costs for cod in a protected ecosystem. The links between diet and diel vertical migration highlight that future work is needed to understand whether the shifts in this behaviour during environmental change (e.g. fishing or climate), could lead to trophic cascades.

Comparative analysis of pancreatic amylase activity in laboratory rodents

Alpha-amylase is the main enzyme for starch digestion in the mammalian gastrointestinal tract. There are species differences in the enzymatic activity of pancreatic amylase that are related to the digestive strategy and natural diet of a species. This aspect is well investigated in pet and farm animals, while in common laboratory animal rodents, information is scarce. In the context of the 3R concept, detailed knowledge of the digestive physiology should be the basis of adequate nutrition, experimental planning and data interpretation. The present study aimed to obtain reference data on amylase activity in pancreatic tissue and duodenal digesta in laboratory mice, rats and hamsters. In addition, digesta was stained with Lugol’s iodine to visualize starch in the process of degradation throughout the gastrointestinal tract. Amylase activity in pancreatic tissue and duodenal digesta was significantly lower in hamsters than rats and mice. The Lugol staining showed intense starch degradation in the hamsters’ forestomachs, presumably by microbial fermentation. A possible explanation is that the prae-duodenal microbial starch fermentation enhances digestibility and reduces the need for pancreatic amylase in hamsters. Rats and mice may rely more on pancreatic amylase for prae-caecal starch digestion, while the microbial fermentation is mainly located in the caecum. The results clearly show species differences in the digestive capacity for starch in mice, rats and hamsters that need to be considered in the feeding of these species in the laboratory setting as well as in the use of rodents as translational animal models.

Blenderized tube feedings: Practice recommendations from the American Society for Parenteral and Enteral Nutrition.

Prior to the 1970s, blending food and liquids and putting them through an enteral access device (EAD) was the most common form of enteral nutrition (EN). However, in the 1970s, blenderized tube feedings (BTFs) became less popular due to the emergence of modern commercial enteral formulas (CEFs). Recently, a cultural shift toward consuming a natural diet, consisting of whole foods, has led to a resurgence in the use of BTF. The increasing use of BTF in a variety of patient care settings identifies a need for practice recommendations that provide guidance for nutrition professionals and patients. Members of the American Society for Parental and Enteral Nutrition (ASPEN) Enteral Nutrition Committee identified salient clinical questions concerning BTF, conducted a comprehensive literature search, and subsequently developed practice recommendations pertaining to the use of BTF. This paper was approved by the ASPEN 2022-2023 Board of Directors.

Extremely high levels of thallium in the natural diet and drinking water of giraffes (Giraffa camelopardalis giraffa)

Extremely high levels of thallium in the natural diet and drinking water of giraffes (Giraffa camelopardalis giraffa)

The evolution of ideas about vegetarianism in British literature in the Late 18th – Early 19th Century (a case of ‘An Essay on Abstinence from Animal Food, as a Moral Duty’ by J. Ritson, ‘Queen Mab’ and ‘A Vindication of Natural Diet’ by P.B. Shelley)

The article examines the literary representation of the topic of vegetarianism in the works of British writers in the Late 18th – Early 19th Century. English sugar merchant, author of popular self-help books Thomas Tryon was one of the first to propose the concept of vegetarianism, which was new to his contemporaries. His works, like those of his followers, inspired Joseph Ritson and Percy Bysshe Shelley. Joseph Ritson in his essay ‘An Essay on Abstinence from Animal Food, as a Moral Duty’ (1802) summarizes the experience of his predecessors and proposes an original concept of vegetarianism, close to the romantic philosophy. P. B. Shelley used Ritson's ideas in his philosophical poem ‘Queen Mab’ (1813) and his essay ‘A Vindication of Natural Diet’ (1813). The article presents the results of a productive dialogue between intellectuals of the Enlightenment (such as T. Tryon and G. Cheyne) and J. Ritson. This influenced the further development of the philosophy of vegetarianism in European culture. Thus, the poet of the romantic era P.B. Shelley, inspired by Ritson's essay, rethought his ideas in his own way and presented them in his works.

Sub-optimal host plants have developmental and thermal fitness costs to the invasive fall armyworm.

The fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith) is a global invasive pest of cereals. Although this pest uses maize and sorghum as its main hosts, it is associated with a wide range of host plants due to its polyphagous nature. Despite the FAW's polyphagy being widely reported in literature, few studies have investigated the effects of the non-preferred conditions or forms (e.g., drought-stressed forms) of this pest's hosts on its physiological and ecological fitness. Thus, the interactive effects of biotic and abiotic stresses on FAW fitness costs or benefits have not been specifically investigated. We therefore assessed the effects of host plant quality on the developmental rates and thermal tolerance of the FAW. Specifically, we reared FAW neonates on three hosts (maize, cowpeas, and pearl millet) under two treatments per host plant [unstressed (well watered) and stressed (water deprived)] until the adult stage. Larval growth rates and pupal weights were determined. Thermal tolerance traits viz critical thermal maxima (CTmax), critical thermal minima (CTmin), heat knockdown time (HKDT), chill-coma recovery time (CCRT), and supercooling points (SCPs) were measured for the emerging adults from each treatment. The results showed that suboptimal diets significantly prolonged the developmental time of FAW larvae and reduced their growth rates and ultimate body weights, but did not impair their full development. Suboptimal diets (comprising non-cereal plants and drought-stressed cereal plants) increased the number of larval instars to eight compared to six for optimal natural diets (unstressed maize and pearl millet). Apart from direct effects, in all cases, suboptimal diets significantly reduced the heat tolerance of FAWs, but their effect on cold tolerance was recorded only in select cases (e.g., SCP). These results suggest host plant effects on the physical and thermal fitness of FAW, indicating a considerable degree of resilience against multiple stressors. This pest's resilience can present major drawbacks to its cultural management using suboptimal hosts (in crop rotations or intercrops) through its ability to survive on most host plants despite their water stress condition and gains in thermal fitness. The fate of FAW population persistence under multivariate environmental stresses is therefore not entirely subject to prior environmental host plant history or quality.

Study of association of the polymorphism rs1799883 of the <i>FABP2</i> gene in children with bronchial asthma associated with obesity

Introduction. Currently, there is a separate phenotype “bronchial asthma – obesity”, manifested by a more severe course of the disease, low rates of achieving asthma control, resistance to basic therapy. Asthma, like obesity, is recognized as a classic example of multifactorial diseases, which are based on a rather complex gene network. The active search for genetic markers characterizing individual characteristics of human metabolism continues. Of particular interest are the genes involved in the regulation of fat and carbohydrate metabolism.Aim. Analysis of associations of polymorphic loci Ala54Thr (G163A) of the FABP2 gene with bronchial asthma of varying severity and control of asthma in children.Materials and methods. 161 children with bronchial asthma in remission were examined by a continuous sampling method, of which 59 patients with obesity of 1-3 degrees without concomitant endocrine pathology. The examination included general clinical, functional, and instrumental methods. The level of asthma control was determined according to the GINA criteria (2018). The biochemical study was carried out on an automatic analyzer SAPPHIRE 400 (Japan). The study of gene polymorphisms was carried out by real-time polymerase chain reaction using sets of “Metabolism” (Research and Production Company “Litekh”, Moscow) on the CFX-96 Biorat device (USA).Results. We have not identified associations of the presence of polymorphic loci of the FABP2 gene with obesity. It was determined that in children with bronchial asthma, the frequency of carrying the homozygous genotype Thr/Thr and the minor allele Thr increased by 1.5 times compared to the control group (OR 9.043; 95%CI [2,093–39,073], p=0.0011 and OR 2.946; 95%CI [1,698‒5,111], p=0.001, respectively), and in children with bronchial asthma with and without asthma control, the carriage of the homozygous Thr/Thr genotype and the rare A allele increased the risk of uncontrolled bronchial asthma (OR 2.42; 95%CI [1.23‒4.79], p=0.03 and OR 1.75; 95%CI [1,119‒2,736], p=0.01), the frequency of the homozygous Ala/Ala genotype and the frequent Ala allele was detected 1.5 times more often in children with bronchial asthma associated with obesity (OR 2.176; 95%CI [1.001‒4.727], p=0.0008 and OR 2.378; 95%CI [1.495‒3.780], p=0.0002, respectively).Conclusion. Although we have not identified associations of the presence of polymorphic loci of the FABP2 gene with obesity, it has been shown that children with Ala54Thr+Thr54Тhr genotypes have significantly higher glucose levels (4.9±0.06 mmol/L compared with carriers of the Ala54Ala genotype 4.0±0.06 mmol/L, p<0.001), cholesterol (4.8±0.4 mmol/L compared with carriers of the Ala54Ala genotype 3.93±0.1 mmol/L, p<0.05) and low density lipoproteins (2.55±0.09 mmol/L compared with carriers of the Ala54Ala genotype 2.26±0.1 mmol/L, p<0.05). There is an obvious need for further investigation of the effect of gene polymorphism on the indicators of carbohydrate and lipid metabolism, depending on the nature of diets. These issues require further study as part of the search for probable cause-and-effect relationships and the creation of personalized programs depending on polymorphic gene variants.

Fungi from the body surface of Spodoptera frugiperda (Lepidoptera: Noctuidae) and bioassay of insecticidal activity

Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important insect pest in Brazil and worldwide, and its control is based mainly on chemical methods that are harmful to the environment and human and animal health. We investigated the fungal community associated with the body surface of S. frugiperda and evaluated the potential of members of this fungal community to act as biocontrol agents. The caterpillars were collected in the field, reared in the laboratory on a natural diet, evaluated for association with fungi on their surface and the environment, and subjected to a bioassay for insecticidal activity. Our results suggest that fungi are often associated with the body of S. frugiperda, as it was possible to obtain these microorganisms from all insects sampled, with a higher frequency of filamentous fungi than yeast. Fusarium verticillioides was the most frequent filamentous fungus species (F3 = 42.1%), followed by Aspergillus aureolus (F2 = 36.8%). Candida pseudointermedia was the most frequent yeast species (L1 = 57.1%). Aspergillus aureolus F2 was the only strain that exhibited toxicity against S. frugiperda and can be considered a good candidate to be explored from the perspective of obtaining biotechnological products of interest for agriculture.

Dietary assessment across various life stages of seven-spotted lady beetle Coccinella septempunctata (Coleoptera: Coccinellidae)

BackgroundCoccinella septempunctata (L.) is an important predator in fighting against aphids on edible crops and vegetables. However, to establish a successful mass-rearing technique, it is crucial to determine the optimal diets for larvae, pupae, and adults in terms of fecundity, longevity, and ingredient ratios. The current study aims to learn more about the biology of ladybird beetle using both artificial and natural food components.ResultsThis study tested six different ratios of natural and artificial diets, ranging from a natural aphid diet to a variety of artificial diets containing protein hydrolyzate, casein protein, honey, dry aphids, yeast, and agar. The results showed that the natural diet (D1) produced from aphids showed approximately 290.2 eggs, while artificial diets D2 and D4 produced 56.5 and 40.2 eggs, respectively. The effect of different diets on the longevity of different life stages was also tested. The minimum longevity of egg, larval, pupal, and adult stages were recorded for D1 and D4. Furthermore, the maximum percentage emergence of larval, pupal, and adult stages was observed for D1 and D2. D6 produced the longest adult duration, with a maximum of 84.60 days. However, there was no significant difference in sex ratio among the various diet components.ConclusionsIn conclusion, the results suggest that artificial diets are essential for sustaining C. septempunctata cultures in laboratories, especially during periods when natural prey is scarce. The most effective and efficient mass-rearing approach would be to provide both natural and artificial foods simultaneously. These findings may have significant implications for the development of biological control strategies for aphids in agriculture.

Food Preponderance Index and Feeding Habit of Macrognathus pancalus, (Hamilton, 1822) from Kotpally Reservoir Vikarabad District, Telangana State, India

The striped spiny eel, Macrognathus pancalus is a widely distributed species of fish in the Mastacembelidae family found in Asia. This study article discusses with the natural diet of M. pancalus as a first step towards understanding its feeding and nutrition, emphasising periodic dietary fluctuations and the link between fish size and diet. The study demonstrates that M. pancalus feeding strategy is more sophisticated than previous reports. GaSI provides details on the conditions around fish feeding. Prior to dissection, the fish's body weight was measured, and a weighing scale was used to determine the weight of the alimentary canal in order to determine the gastrosomatic index of the fish. The 'index of preponderance method was used to determine the relative importance of each dietary item. In the present study, 392fish species of M. pancalus relative lengths of the gut (RLG) was measured during the study period from February 22 to January 23. The study revealed minimal variation in the different sizes and lengths of fish species. The lowest value was 0.55± 0.11 in the 19–21 cm group, while the highest value was 0.68 ± 0.14 in the 6–8 cm group In general, the RLG value was higher in the younger size groups of the species. Monthly fluctuations in feeding percentage intensities of the gut were determined to be 8.38% with full gut, 23.20% with 3/4th full gut, 31.84% with 1/2th full gut, 23.79% with 1/4th full gut 7.61% with full gut, and 12.43% empty. In the present investigation, the fullness of gut in different maturity stages showed that higher active feeding (22.91% with 3/4full & 9.37% with full gut 23.52% with 1/2 full) were found in maturing stage; moderate (1/2 full with 23.52%) were found in immature stage; highest percentage of poor feeding (51.21% with empty and nearly empty29.26%) were recorded in ripe stage. More empty stomachs (16.67%) and ½ full with 26.19% were found in spent stage. The preponderance index values of M. pancalus showed that the insect larvae were the most favored food item (65.26%) for this species, followed by zooplankton (14.33%), digested food (13.76%), crustaceans (3.12%), sand and mud (2.71%), annelids (0.62%), molluscans (0.16%), and fish scales (0.007%).

The Relationship between Age, Gender, BMI, Diet, Salivary pH and Periodontal Pathogenic Bacteria in Children and Adolescents: A Cross-Sectional Study.

The oral microbiome can be influenced by many factors and its dysbiosis can have negative effects on oral and general health. The purpose of this study was to analyze the intensity of 11 periodontal pathogenic microorganisms identified in the oral cavity of a sample of children and adolescents from Oradea, Romania and to investigate the association of some variables (age, gender, body mass index, diet, and salivary pH) with the identified microorganisms. The cross-sectional study was conducted on a group of clinically healthy patients under the age of 18 years from Oradea, Romania. For the analysis of the periodontal pathogens, the micro-IDent kit was used, which determines 11 bacterial markers for periodontitis and peri-implantitis. The kit is based on the polymerase chain reaction (PCR). Bacterial sampling was carried out according to the manufacturer's instructions. A total of 60 children (23 male, 37 female) were included in this study, and were divided into three different age categories. No statistically significant results were identified for gender. However statistically significant results were obtained for other variables. Positive results for Prevotella intermedia and Bacteroides forsythus were associated with ages between 13 and 18 years, while positive results for Capnocytophaga spp. were associated with ages between 2 and 5 years. Positive results for Prevotella intermedia, Bacteroides forsythus, Peptostreptococcus micros, Campylobacter rectus and Eikenella corodens were associated with an overweight BMI. Negative results for Prevotella intermedia and Eikenella corodens were associated with a natural diet in the first 6 months of life. Positive results for Fusobacterium nucleatum and Campylobacter rectus were associated with an acidic salivary pH. In this study, the identified periodontal pathogens were associated with age, body mass index, diet in the first 6 months of life, and salivary pH.

Influence of natural and non-natural diets on the fitness and rearing of Pectinophora gossypiella Saunders

In order to develop integrated management approaches for Pectinophora gossypiella, basic studies are crucial. The two-sex life table is the most important tool for describing the fitness and population parameters of both sexes (male and female) of an insect, while the traditional life table only explains the female sex of an insect. However, no study has reported on the biology of P. gossypiella using two-sex life table tools. Therefore, this study explains the rearing dynamics of P. gossypiella on a cotton seed-based artificial diet and a natural diet (mature cotton bolls). According to the results, the oviposition period of P. gossypiella was recorded to be longer on the artificial diet (9.07 ± 0.24) compared to the natural diet (7.40 ± 0.11). The total fecundity of P. gossypiella was greater on the artificial diet (125.94 ± 3.06) in comparison to the natural diet (60.37 ± 1.10). The population parameters, including intrinsic rate of increase, finite rate of increase, gross reproductive rate, and net reproductive rate of P. gossypiella were highest on the artificial diet in comparison to the natural diet. This study concluded that the cotton seed-based artificial diet was most suitable for the rearing of P. gossypiella. In the future, P. gossypiella may be studied in depth in light of the findings in this study.

Peri‐urban systems alter trophic niche size and overlap in sympatric coastal bird species

AbstractUrban habitats can create empty trophic niche space by providing abundant alternative dietary resources, allowing some generalist species to either shift or expand their trophic niches. Resulting changes to trophic niche size may consequently affect interspecific interactions and competition, although trophic impacts are less clear in peri‐urban systems, where both natural and urban resources are readily accessible to highly mobile species. We combined stable isotope (δ13C, δ15N, δ34S) data with GPS tracking of two sympatric coastal bird species (Larus argentatus, L. marinus) across four study sites on the east coast of the United States, ranging from a study site in New York City (the most populous city in the United States) to less‐urban sites off Massachusetts. We quantified the trophic niche size and trophic niche overlap in three‐dimensional isotopic space and assessed spatial overlap in foraging habitat between species at both peri‐urban and less‐urban study sites. We found that for both species, birds at peri‐urban study sites had significantly larger trophic niches than birds from the less‐urban sites. Furthermore, for study sites where both species occurred, we found that overlap in trophic niche space and foraging habitats between species was lower at the peri‐urban study site than at the less‐urban site. These results suggest that peri‐urban environments may facilitate trophic niche expansion and decrease niche overlap in mobile generalist species, contrasting with previous studies showing increased trophic niche overlap in more isolated urban populations. Following further analysis, we found that trophic niche expansion was facilitated by both within‐ and between‐individual differences in foraging strategies. We posit that peri‐urban environments, particularly along coastal areas, can reduce interspecific competition between sympatric species by providing access to a variety of natural and anthropogenic diet items, especially for highly mobile generalist consumers that can access both natural and urban foraging areas. Research assessing how and at what scale peri‐urban systems influence wildlife is key to understanding how further global urbanization will shape ecosystem structures.

Global trends of cancer: The role of diet, lifestyle, and environmental factors.

Effective treatment of cancer requires understanding the nature of the disease and accurately addressing the main root causes. General risk factors for cancer include poor nutrition, an acidogenic diet, an unhealthy lifestyle, and exposure to carcinogens such as toxins, chemicals, and radiation. The risk of developing cancers may be reduced by sufficient oxygenation and maintaining optimal alkalinity and nutritional balance at the cell level. The review paper summarizes some diet and lifestyle modifications that may potentially be considered for preventing and controlling some cancers. Moreover, worldwide statistical data for cancer incidence rates published by International Agency for Research on Cancer are analyzed for certain cancers regionally, concerning the effect of dietary habits and environmental factors that meaningfully correlate with the global trends of cancer. The study of cancer root causes integrated with analyzing the statistics related to cancer incidence rates suggests that the risk of developing cancer may be reduced by modifying dietary habits and lifestyle factors, as well as reducing exposure to carcinogens. Those with healthy balanced dietary habits may have a lower cancer risk than those who frequently have unhealthy diets; hence, considering a balanced natural diet and healthy lifestyle may be suggested as a complementary or alternative solution in cancer treatments.

Insect-Based Feed Acceptance amongst Consumers and Farmers in Ireland: A Pilot Study

The potential of insect-based feed (IBF) as a sustainable alternative to conventional animal feed is widely reported, yet there is extremely limited information on its acceptance in Ireland, a country with a strong farming background. Therefore, this study aims to provide baseline data on factors affecting acceptance of IBF amongst a segment of consumers and farmers in Ireland. Quantitative and qualitative data were collected amongst 233 consumers, 73 of which were farmers. Non-parametric statistical tests revealed that the willingness to consume foods from animals fed with IBF depends on the type of food and is affected by a combination of consumer- and product-related factors. Consumers’ age, gender, diet, and education level, the foods’ packaging information, safety, and price, and whether insects are part of an animal’s natural diet or environmentally friendly had a significant effect. Safety concern regarding use of IBF was the main factor affecting farmers’ willingness to use it. Qualitative findings revealed concerns emanating from the bovine spongiform encephalopathy outbreak and a general need for more information. Accordingly, information on the benefits of using IBF increased its acceptance. Thus, IBF acceptance might depend on dedicated educational interventions which include addressing the safety aspect of the feed even among those with higher level of education.

Exploring the potential links between gut microbiota composition and natural populations management in wild boar (Sus scrofa)

We surveyed wild boar (Sus scrofa) populations using 16S rRNA gene analysis of the gut microbiota in fresh faeces taken from 88 animals hunted in 16 hunting estates. The wild boar is a very convenient model system to explore how environmental factors including game management, food availability, disease prevalence, and behaviour may affect different biological components of wild individuals with potential implications in management and conservation. We tested the hypotheses that diet (according to stable carbon isotopes analyses), gender (i.e., animal behaviour studying males and females), and both health (analyses of serum samples to detect exposure to several diseases) and form statutes (i.e., thoracic circumference in adults) are reflected in changes in the intestinal microbiota. We focused on a gut functional biomarker index combining Oscillospiraceae and Ruminococcaceae vs. Enterobacteriaceae. We found that gender and the estate (population) were explanatory variables (c.a. 28% of the variance), albeit a high degree of overlapping among individuals was observed. The individuals with higher abundance of Enterobacteriaceae showed a gut microbiota with low diversity, mostly in males. Significant statistical differences for thoracic circumference were not found between males and females. Interestingly, the thoracic circumference was significantly and inversely related to the relative abundance of Enterobacteriaceae in males. Overall, we found that diet, gender, and form status were major factors that could be related to the composition and diversity of the gut microbiota. A high variability was observed in the biomarker index for populations with natural diet (rich in C3 plants). Although, we noticed a marginally significant negative trend between the index (higher abundance of Enterobacteriaceae) and the continuous feeding of C4 plants (i.e., supplementary maize) in the diet of males. This result suggests that continuous artificial feeding in hunting estates could be one of the factors negatively influencing the gut microbiota and the form status of wild boars that deserves further investigations.

Fatty acid isotopic composition in Atlantic pollock is not influenced by environmentally relevant dietary fat concentrations.

The application of fatty acid (FA) isotopic analysis has great potential in elucidating food web structure, but it has not experienced the same wide-spread use as amino acid isotopic analyses. The failure to adopt FA isotopic methods is almost certainly linked to a lack of reliable information on trophic fractionation of FA, particularly in higher predators. In this work, we attempt to address this shortfall, through comparison of FA δ13C values in captive Atlantic pollock (Pollachius virens) liver and their known diets. Since catabolism is likely the main cause of fractionation and it may vary with dietary fat content, we investigated the impact of dietary fat concentration on isotopic discrimination in FA. We fed Atlantic pollock three formulated diets with similar FA isotopic compositions but different fat concentrations (5-9% of diet), representative of the range found in natural prey, for 20weeks. At the conclusion of the study, δ13C values of liver FA were very similar to the FA within the corresponding diets, with most discrimination factors < 1. For all FA except 22:6n-3, dietary fat had no effect on discrimination factors. Only for 22:6n-3 did fish fed the highest fat diet have lower δ13C values than the diet consumed. Thus, these FA-specific discrimination factors can be applied to evaluate diets in marine fish consuming natural diets and will serve as additional and valuable biomarkers in fish feeding ecology.

Elucidating the trophic role of Tapinoma ibericum (Hymenoptera: Formicidae) as a potential predator of olive pests

AbstractAnts play a key role in improving the structure and function of local communities. They interact with plants, herbivores, predators and parasitoids and are able to change their trophic role in space and time. These features, however, make it difficult to establish the net trophic role of ants in agroecosystems. Here we aim to determine the isotopic enrichment and tissue incorporation rates in ants of the Tapinoma nigerrimum complex, which are found abundantly in olive orchards (i.e. T. ibericum), to determine their trophic role through stable isotopes analysis. We compared the isotopic signature of ants feeding on (1) natural diets, (2) experimental diets and (3) contrasting diets of ants inhabiting natural habitats and olive orchards with different management systems. Then, we contrasted our isotopic results on natural diets with the prey of ant foragers in olive orchards. Our results showed that (1) ants from olive orchards had an isotopic signature different from that of a hyper‐predator; (2) the isotopic signature did not vary significantly amongst different management practices and (3) the diet of ants in nature varies greatly on preys according to resource availability, which may be reflected in isotopic signatures. Therefore, T. ibericum is a species that can potentially contribute to control olive pests without posing a risk to other natural enemies because commonly it is not a hyper‐predator. The information presented here could be used by farmers and technicians to enhance local biological control planning and/or strategies in olive orchards.

Diet-induced changes in fecal microbiota composition and diversity in dogs (Canis lupus familiaris): A comparative study of BARF-type and commercial diets

BackgroundDiet is known to strongly modulate the composition of the gut microbiota, thereby affecting health conditions and disease. Natural BARF-type and commercial diets have been used for feeding pets (e.g. dogs and cats) promoting changes in the canine microbiota in terms of abundance, richness, and diversity that may favor certain metabolic processes and resistance to certain infectious agents. Therefore, the present study sought to identify microbiota changes in dogs fed with a BARF-type diet versus dogs fed with a commercial diet by sequencing the V4 region of the 16S rRNA gene. MethodsThe microbiota of dogs fed with the BARF-diet (n = 20) and commercial-diet (n = 26) was studied using fecal samples. A metabarcoding strategy was employed by sequencing the V4 hypervariable region of the 16S rRNA gene using the Illumina HiSeq platform. DADA2 was used to assess the quality profile of the reads and to determine the core sample inference algorithm of the reads to infer amplicon sequence variants (ASVs). The taxonomic assignment was performed using sequences from the Silva v138 formatted reference database. The microbial diversity analysis was performed using the R package Phyloseq, which was used to calculate diversity and abundance indices and construct the respective graphs. Linear discriminant analysis (LDA) effect size analysis (LEfSe) was used to identify the differentially abundant taxa in the BARF group versus the commercial-diet group. ResultsThe diet causes changes in fecal microbiota composition and diversity, with richness and diversity being higher in BARF-fed dogs. Beta diversity analyses confirmed that diet is directly related to microbiota composition regardless of breed or sex. Differentially enriched taxa were identified in each of the diets as Fusobacterium, Bacteroides, and Clostridium perfringens in BARF-fed dogs and Prevotella, Turicibacter, Faecalibacterium, and Peptacetobacter (Clostridium) hiranonis, mostly relevant in carbohydrate metabolism, in commercial-fed dogs. ConclusionsThis study is the first one carried out in dogs from Colombia that seeks to identify changes in the intestinal microbiota concerning natural BARF type diet and commercial diet using a metabarcoding approach. Important differences were identified in terms of richness, diversity, and differentially enriched bacteria in each of the diets. The microbiota of dogs fed the BARF diet was characterized by higher richness and diversity compared to the commercial diet. However, it was identified that BARF-fed dogs can potentially acquire more opportunistic infections by pathogens of importance such as C. perfringens. Most of the taxa enriched in commercial diet-fed dogs are linked to carbohydrate metabolism, which may be directly related to diet composition.