Food Chain System Research Articles

Evaluating Ecosystem Characteristics and Ecological Carrying Capacity for Marine Fauna Stock Enhancement Within a Marine Ranching System

China has recently launched extensive marine ranching projects, highlighting the need for scientific evaluation of ecosystem structure and function to guide their development. This study established two energy flow models and an evaluation index system to assess the structure, function, carrying capacity, and ecological status of both a marine ranching ecosystem and a nearby control site in the Beibu Gulf. The results show that the ranching ecosystem outperformed the control ecosystem in terms of food chain length, system size, and ecological carrying capacity of economically important species. The ranching ecosystem was classified as “relatively good”, while the control ecosystem was deemed “relatively poor”, which may confirm the success of the ranching efforts. Mussels, large crabs, and scorpaenidae were identified as key species for stock enhancement based on their biomass potential. Scenario simulations using Ecosim, driven by biomass and fishing factors, indicate that stock enhancement strategies targeting MOB (mussels, oysters, and barnacles) significantly improved the ranching ecosystem, raising its status to “good”. However, the simulations also revealed that stock enhancement had limited effects on optimizing food web structure, system organization, and energy transfer efficiency, suggesting that a combination of strategies is necessary for further improvement.

Complex Dynamics and PID Control Strategies for a Fractional Three-Population Model

In recent decades, there have been many studies on Hopf bifurcation and population stability with time delay. However, the stability and Hopf bifurcation of fractional-order population systems with time delay are lower. In this paper, we discuss the dynamic behavior of a fractional-order three-population model with pregnancy delay using Laplace transform of fractional differential equations, stability and bifurcation theory, and MATLAB software. The specific conditions of local asymptotic stability and Hopf bifurcation for fractional-order time-delay systems are determined. A fractional-order proportional–integral–derivative (PID) controller is applied to the three-population food chain system for the first time. The convergent speed and vibration amplitude of the system can be changed by PID control. For example, after fixing the values of the integral control gain ki and the differential control gain kd, the amplitude of the system decreases and the convergence speed changes as the proportional control gain kp decreases. The effectiveness of the PID control strategy in complex ecosystem is proved. The numerical simulation results are in good agreement with the theoretical analysis. The research in this paper has potential application values concerning the management of complex population systems. The bifurcation theory of fractional-order time-delay systems is also enriched.

Evaluation of food pattern behaviours following nutritional education for health professionals

Abstract Background The “Work Programme - UN Decade of action on nutrition 2016-2025” highlights the importance of implementing Recommendation 19 of the Second International Conference on Nutrition of FAO and WHO related to nutrition education interventions (NEI) for health professionals (HP), in order to develop nutritional skills based on national dietary guidelines and coherent policies relating to food. The Local Health Agency integrated with Trieste University (ASUGI), since 2009, has performed 25 NEI with the formation of 910 HP. Post pandemic, the content of ASUGI’s last 5 NEI, programmed by the prevention plan of the Autonomous Region of Friuli Venezia Giulia, was aligned with the principles of the European Farm to Fork Strategy linked to Sustainable Healthy Diets (SHD). Objectives The objectives of the training programme (TP), approved for Continuing Medical Education, was to change and evaluate food pattern behaviour (FPB) of HP (n = 200) to adhere to the SHD. TP was characterized by a systemic view on complex interconnections between nutritional and sensorial food value, sustainability of food chain systems, evolution of urban food environments, as contexts into which SHD choices can be applied. The 2 days training, spread over 14 hours with 40 participants, concluded with interactive work and experiences to applied knowledge and beginning to make informed healthy dietary choices in practice. Results 6 months after the conclusion of TP it was reported that the percentage of HP who consumed the recommended portions of fruits and vegetables had increased from 62% to 70% and from 28% to 35% respectively, while those who consumed no cured meats, red meats or legumes, changed from 24% to 35%, from 19% to 25%, from 6% to 3% respectively. Conclusions The evaluation of the TP systemic structure has shown its effectiveness in improving some healthy FPB of HP and the importance of applying a continuous improvement process of the program to better adhere to the whole SHD. Key messages • The systemic and integrated structure of nutritional education intervention programs for health professionals contributes to improving their healthy food pattern behaviour. • The relationships between complex policies of food systems and the 17 SDGs included in the training programs on nutrition education are useful for promoting adherence to healthy and sustainable diets.

Antibiotic resistance genes are transferred from manure-contaminated water bodies to the gut microbiota of animals through the food chain

Fecal-contaminated water may enter the food chain and become an important route for the transmission of antibiotic resistance genes (ARGs) to the human microbiome. However, little is known about the spread of ARGs from fecal contamination in water bodies along the aquatic food chain. In this study, laboratory-raised Daphnia magna and Aristichthys nobilis were used to investigate the effects of the addition of manure on target ARGs in water and their intestinal contents to determine the potential transmission route of ARGs in the aquatic food chain system. The abundance of target ARGs in water as well as D. magna and A. nobilis intestinal contents significantly increased when fecal contamination was present. ARGs bioaccumulated along the food chain, with four ARGs (tetM-01, tetX, qnrS, and sul2) detected regularly. Mn and Cr were key environmental factors that promoted the transfer of ARGs along the food chain. Fecal addition significantly changed the structure of microbial communities in water, D. magna gut, and A. nobilis gut. The ARG spectrum was significantly correlated with the composition and structure of the bacterial community. Proteobacteria, Bacteroidetes, and Firmicutes were identified as the main host bacteria and were likely to act as carriers of ARGs to promote the spread of antibiotic resistance in the food chain. The composition and structure of bacterial communities, along with mobile genetic elements, were two key drivers of ARG transfer. These findings provide new insights into the distribution and spread of ARGs along the freshwater food chain.

Dynamics of a ratio-dependent three-species food-chain system in a random environment

We consider a system of stochastic differential equations, which is established by introducing white noises into a periodic and ratio-dependent food-chain system of three-species. We investigate the asymptotic behaviors for such a system, and obtain the sufficient conditions for its extinction and persistence with the help of Itô’s formula. We discuss the existence of a nontrivial positive periodic solution based on Has’minskii theory of periodic solution. Further, we study a ratio-dependent food-chain system of three-species including not only white noise but also telephone noise. For such a model, we give the sufficient conditions to guarantee the existence of a unique ergodic stationary distribution.

Chaos and extinction risks of sexually reproductive generalist top predator in a seasonally forced food chain system with Allee effect.

This paper investigates the dynamics of a tritrophic food chain model incorporating an Allee effect, sexually reproductive generalist top predators, and Holling type IV and Beddington-DeAngelis functional responses for interactions across different trophic levels. Analytically, we explore the feasible equilibria, their local stability, and various bifurcations, including Hopf, saddle-node, transcritical, and Bogdanov-Takens bifurcations. Numerical findings suggest that higher Allee intensity in prey growth leads to the inability of species coexistence, resulting in a decline in species density. Likewise, a lower reproduction rate and a higher strength of intraspecific competition among top predators also prevent the coexistence of species. Conversely, a rapid increase in the reproduction rate and a decrease in the strength of intraspecific competition among top predators enhance the densities of prey and top predators while decreasing intermediate predator density. We also reveal the presence of bistability and tristability phenomena within the system. Furthermore, we extend our autonomous model to its nonautonomous counterpart by introducing seasonally perturbed parameters. Numerical analysis of the nonautonomous model reveals that higher seasonal strength in the reproduction rate and intraspecific competition of top predators induce chaotic behavior, which is also confirmed by the maximum Lyapunov exponent. Additionally, we observe that seasonality may lead to the extinction of species from the ecosystem. Factors such as the Allee effect and growth rate of prey can cause periodicity in population densities. Understanding these trends is critical for controlling changes in population density within the ecosystem. Ecologists, environmentalists, and policymakers stand to benefit significantly from the invaluable insights garnered from this study. Specifically, our findings offer pivotal guidance for shaping future strategies aimed at safeguarding biodiversity and maintaining ecological stability amidst changing environmental conditions. By contributing to the existing body of knowledge, our study advances the field of ecological science, enhancing the comprehension of predator-prey dynamics across diverse ecological conditions.

Effect of multiple gestation delays in a prey–predator food chain system with infected class of prey

Effect of multiple gestation delays in a prey–predator food chain system with infected class of prey

Global stability analysis and Hopf bifurcation due to memory delay in a novel memory‐based diffusion three‐species food chain system with weak Allee effect

This paper presents a detailed study on the dynamics of a three‐species food chain system with memory‐based delay under weak Allee effect and middle predator refuge. The local stability analyses of the non‐diffusive and memory‐based diffusion systems are investigated. Moreover, we give a priori estimates and obtain the existence of the positive constant steady state by applying the comparison theorem. Sufficient conditions for the global stability are established by Barbǎlat lemma and the Lyapunov function. The theoretical results suggest the joint effect of cross‐diffusion and memory‐based delay can lead to Hopf bifurcation, which cannot appear in the system with self‐diffusion or a small cross‐diffusion coefficient. Numerical results verify the validity of the theoretical analysis.

Macrogenomes reveal microbial-mediated microplastic degradation pathways in the porcine gut: a hope for solving the environmental challenges of microplastics.

It is increasingly recognized that microplastics (MPs) are being transmitted through the food chain system, but little is known about the microorganisms involved in MP degradation, functional biodegradation genes, and metabolic pathways of degradation in the intestinal tract of foodborne animals. In this study, we explored the potential flora mainly involved in MP degradation in the intestinal tracts of Taoyuan, Duroc, and Xiangcun pigs by macrogenomics, screened relevant MP degradation genes, and identified key enzymes and their mechanisms. The pig colon was enriched with abundant MP degradation-related genes, and gut microorganisms were their main hosts. The fiber diet did not significantly affect the abundance of MP degradation-related genes but significantly reduced their diversity. We identified a total of 94 functional genes for MP degradation and classified them into 27 categories by substrate type, with polystyrene (PS), polyethylene terephthalate (PET), and di(2-ethylhexyl) phthalate (DEHP) were the most predominant degradation types. The MP degradation functional genes were widely distributed in a variety of bacteria, mainly in the phylum Firmicutes and Bacteroidetes. Based on the identified functional genes for MP degradation, we proposed a hypothetical degradation mechanism for the three major MP pollutants, namely, PS, PET, and DEHP, which mainly consist of oxidoreductase, hydrolase, transferase, ligase, laccase, and isomerase. The degradation process involves the breakdown of long polymer chains, the oxidation of short-chain oligomers, the conversion of catechols, and the achievement of complete mineralization. Our findings provide insights into the function of MP degradation genes and their host microorganisms in the porcine colon.

Fractional dynamics and computational analysis of food chain model with disease in intermediate predator

<abstract> <p>In this paper, a fractional food chain system consisting of a Holling type Ⅱ functional response was studied in view of a fractional derivative operator. The considered fractional derivative operator provided nonsingular as well as a nonlocal kernel which was significantly better than other derivative operators. Fractional order modeling of a model was also useful to model the behavior of real systems and in the investigation of dynamical systems. This model depicted the relationship among four types of species: prey, susceptible intermediate predators (IP), infected intermediate predators, and apex predators. One of the significant aspects of this model was the inclusion of Michaelis-Menten type or Holling type Ⅱ functional response to represent the predator-prey link. A functional response depicted the rate at which the normal predator consumed the prey. The qualitative property and assumptions of the model were discussed in detail. The present work discussed the dynamics and analytical behavior of the food chain model in the context of fractional modeling. This study also examined the existence and uniqueness related analysis of solutions to the food chain system. In addition, the Ulam-Hyers stability approach was also discussed for the model. Moreover, the present work examined the numerical approach for the solution and simulation for the model with the help of graphical presentations.</p> </abstract>

Analysis of a stochastic Leslie-Gower three-species food chain system with Holling-II functional response and Ornstein-Uhlenbeck process

<abstract><p>This paper studies a stochastic Leslie-Gower model with a Holling-II functional response that is driven by the Ornstein-Uhlenbeck process. Some asymptotic properties of the solution of the stochastic Leslie-Gower model are introduced: The existence and uniqueness of the global solution of the model are given; the ultimate boundedness of the model is proven; by constructing the Lyapunov function and applying Ito's formula, the existence of the stationary distribution of the model is demonstrated; and the conditions for system extinction are discussed. Finally, numerical simulations are used to validate our conclusion.</p></abstract>

Optimal control problem of a discrete spatiotemporal prey–predator three-species fishery model

In this work, we discuss a spatiotemporal discrete prey–predator model. It consists of three compartments: prey, predator, and super-predator. The proposed model describes the interaction between prey, predator, and super-predator in a region with a discrete displacement. We also provide research on appropriate regional control strategies. The controls are applied to the predator and the super-predator, respectively; they represent catching these in measured quantities in a space and a time chosen. The aim is to increase the number of prey and reduce the number of predators, restore the food chain system, and ensure its sustainability. Finally, we provide graphical visuals and numerical simulations to support our analytical findings.

Ecologically different earthworm species are the driving force of microbial hotspots influencing Pb uptake by the leafy vegetable Brassica campestris.

Food chain contamination by soil lead (Pb), beginning with Pb uptake by leafy vegetables, is a threat to food safety and poses a potential risk to human health. This study highlights the importance of two ecologically different earthworm species (the anecic species Amynthas aspergillum and the epigeic species Eisenia fetida) as the driving force of microbial hotspots to enhance Pb accumulation in the leafy vegetable Brassica campestris at different Pb contamination levels (0, 100, 500, and 1,000 mg·kg-1). The fingerprints of phospholipid fatty acids (PLFAs) were employed to reveal the microbial mechanism of Pb accumulation involving earthworm-plant interaction, as PLFAs provide a general profile of soil microbial biomass and community structure. The results showed that Gram-positive (G+) bacteria dominated the microbial community. At 0 mg·kg-1 Pb, the presence of earthworms significantly reduced the total PLFAs. The maximum total of PLFAs was found at 100 mg·kg-1 Pb with E. fetida inoculation. A significant shift in the bacterial community was observed in the treatments with E. fetida inoculation at 500 and 1,000 mg·kg-1 Pb, where the G+/G- bacteria ratio was significantly decreased compared to no earthworm inoculation. Principal component analysis (PCA) showed that E. fetida had a greater effect on soil microbial hotspots than A. aspergillum, thus having a greater effect on the Pb uptake by B. campestris. Redundancy analysis (RDA) showed that soil microbial biomass and structure explained 43.0% (R2 = 0.53) of the total variation in Pb uptake by B. campestris, compared to 9.51% of microbial activity. G- bacteria explained 23.2% of the total variation in the Pb uptake by B. campestris, significantly higher than the other microbes. The Mantel test showed that microbial properties significantly influenced Pb uptake by B. campestris under the driving force of earthworms. E. fetida inoculation was favorable for the G- bacterial community, whereas A. aspergillum inoculation was favorable for the fungal community. Both microbial communities facilitated the entry of Pb into the vegetable food chain system. This study delivers novel evidence and meaningful insights into how earthworms prime the microbial mechanism of Pb uptake by leafy vegetables by influencing soil microbial biomass and community composition. Comprehensive metagenomics analysis can be employed in future studies to identify the microbial strains promoting Pb migration and develop effective strategies to mitigate Pb contamination in food chains.

Fecal antibiotic resistance genes were transferred through the distribution of soil-lettuce-snail food chain.

Massive antibiotic resistance genes (ARG) were detected in the soil modified by manure, which may affect human life safety through the food chain. However, the transmission of ARGs through the soil-plant-animal food chain is still unclear. Therefore, this study used high-throughput quantitative PCR technology to explore the effects of pig manure application on ARGs and bacterial communities in soil, lettuce phyllosphere, and snail excrement. The results showed that a total of 384 ARGs and 48 MEGs were detected in all samples after 75days of incubation. The diversity of ARGs and MGEs in soil components increased significantly by 87.04% and 40% with the addition of pig manure. The absolute abundance of ARGs in the phyllosphere of lettuce was significantly higher than that of the control group, with a growth rate of 212.5%. Six common ARGs were detected between the three components of the fertilization group, indicating that there was internal transmission of fecal ARGs between the trophic levels of the food chain. Firmicutes and Proteobacteria were identified as the dominant host bacteria in the food chain system, which were more likely to be used as carriers of ARGs to promote the spread of resistance in the food chain. The results were used to assess the potential ecological risks of livestock and poultry manure. It provides theoretical basis and scientific support for the formulation of ARG prevention and control policies.

Complex dynamics induced by multiple gestation delays in a Leslie–Gower‐type system with competitive interference

The dynamics of food consumption by higher trophic level is complicated as its availability, choice, and consequently their development. The top predator interference has a strong influence on the dynamic structure of the tritrophic food chain system. The proposed article deals with the characteristic features of a three‐tire modified Leslie–Gower model with a one‐prey two‐predator system with the assumption of multiple gestation delays. The intermediate predator of the food chain is taken as a specialist type, whereas the growth of top predator is assumed by sexual reproduction. Two different response functions named Monod–Haldane (M‐H) and Beddington–DeAngelis (B‐D) are considered for the modeling of system dynamics. The population densities of intermediate and top predators are assumed to be affected by two different gestation delays. The boundedness and positive equilibria and their stability conditions are examined theoretically for the delay‐free system. The local and global stability conditions of the delayed system are also determined. With the help of normal form theory and central manifold arguments, the properties of bifurcating periodic solutions are carried out. The numerical computation is performed to validate our analytical findings that show the different dynamical outcomes such as periodic and chaotic dynamics. The Hopf‐bifurcation scenario for different parameters of the model system is well studied. Further, the stability behavior of multiple delays for the different cases is investigated. The system shows chaotic behavior when the gestation delay of intermediate predators is large enough. It is also observed that the top predator density is highly fluctuating through the creation of chaos by the inclusion of time delay. Finally, the time delay destabilizing effect is noticed for three‐way interactions among prey, intermediate predator, and top predator, highlighting its significance in chaotic dynamics.

Recent Advancements in Fisheries Systems and Applications for Animal Growth in Water-Borne Animals Fisheries Systems

Advances in fisheries system have been made in the few past years due to different technological progress in the food chain system by improving the mutual communication among different types of organisms. Overfishing, anthropogenic climate change, and pollution are already having measurable impacts on the marine environment throughout the majority of the globe, and their potential long-term repercussions are very concerning. Fishing activity contributes to marine debris; the proportional contribution of recreational fishing has not been quantified. New approaches that are being used in various ways include the precautionary approach, the ecological approach, adaptive management, and harvest control rules. Growth in coastal population has made water and land pollution worse and placed additional pressure on coastal development. Satellite remote sensing has been an essential tool in fishery research, management, and harvesting because it offers synoptic ocean measurements for evaluating environmental influences on the abundance and distribution of fish populations and allows ecological analyses at community and ecosystem scales. Synthetic super-active analogues with higher inducing potency at lower doses were developed using biotechnological techniques including protein engineering and recombinant DNA technology. There are many methods of preservation, including as drying, smoking, freezing, chilling, and brining. Fish that has been smoked or dried has more nutrients and is easier to digest. Fish is often prepared by smoking or drying; both processes eliminate moisture by heating, which reduces the development of germs and increases shelf life. Advances in genetic engineering also helpful for improving the new varieties in the fisheries system.

Effectiveness of phase synchronization in chaotic food chain model with refugia and Allee effects during seasonal fluctuations.

Seasonal effects powerfully shape the population dynamics with periodic climate changes because species naturally adjust their dynamics with seasonal variations. In response to these effects, sometimes population dynamics exhibit synchrony or generate chaos. However, synchronized dynamics enhance species' persistence in naturally unstable environments; thus, it is imperative to identify parameters that alter the dynamics of an ecosystem and bring it into synchrony. This study examines how ecological parameters enable species to adapt their dynamics to seasonal changes and achieve phase synchrony within ecosystems. For this, we incorporate seasonal effects as a periodic sinusoidal function into a tri-trophic food chain system where two crucial bio-controlling parameters, Allee and refugia effects, are already present. First, it is shown that the seasonal effects disrupt the limit cycle and bring chaos to the system. Further, we perform rigorous mathematical analysis to perform the dynamical and analytical properties of the nonautonomous version of the system. These properties include sensitive dependence on initial condition (SDIC), sensitivity analysis, bifurcation results, the positivity and boundedness of the solution, permanence, ultimate boundedness, and extinction scenarios of species. The SDIC characterizes the presence of chaotic oscillations in the system. Sensitivity analysis determines the parameters that significantly affect the outcome of numerical simulations. The bifurcation study concerning seasonal parameters shows a higher dependency of species on the frequency of seasonal changes than the severity of the season. The bifurcation study also examines the bio-controlling parameters and reveals various dynamic states within the system, such as fold, transcritical branch points, and Hopf points. Moreover, the mathematical analysis of our seasonally perturbed system reveals the periodic coexistence of all species and a globally attractive solution under certain parametric constraints. Finally, we examine the role of essential parameters that contribute to phase synchrony. For this, we numerically investigate the defining role of the coupling dimension coefficient, bio-controlling parameters, and other parameters associated with seasonality. This study infers that species can tune their dynamics to seasonal effects with low seasonal frequency, whereas the species' tolerance for the severity of seasonal effects is relatively high. The research also sheds light on the correlation between the degree of phase synchrony, prey biomass levels, and the severity of seasonal forcing. This study offers valuable insights into the dynamics of ecosystems affected by seasonal perturbations, with implications for conservation and management strategies.

The Occurrence of Serotypes and Virulence Genes of Listeria monocytogenes in Various Food Products

Background: Given that controlling Listeria contamination is very important in food chain system, the knowledge of their prevalence in food is very important. Therefore, this study aims to examine the prevalence of important Listeria species in various food types and evaluate serotype distribution, as well as the study of the virulence factors of L. monocytogenes. Methods: During July 2018 and January 2020, 900 food samples were collected in the North of Iran, including beef, chicken, fish, shrimp, milk and yogurt, green vegetables, mixed vegetable salad, Olivier salad, and cottage cheese. After isolation and identification steps, each bacterial DNA was extracted. Then, using specific primers, species, serotypes, and virulence genes of Listeria isolates were evaluated in the samples by Polymerase Chain Reaction (PCR) method. Results: The test results of 136 samples (15.1%) were positive for Listeria spp. and the most contaminated food was beef (35%) followed by chicken (29%) and green vegetables (23%). The most isolated Listeria spp. was L. monocytogenes and L. ivanovii. Among L. monocytogenes isolates, the dominant serogroups were 1/2a and 4b; furthermore, all of the isolates of this species harbored four virulence genes, including hlyA, plc, iap, and actA. Conclusion: These reports highlighted the importance of food safety in various food products, particularly raw meats and vegetables. Moreover, contamination of healthy foods such as fish and vegetables with Listeria is an indicator of public health.

A narrative action on the battle against hunger using mushroom, peanut, and soybean-based wastes.

Numerous generations have been affected by hunger, which still affects hundreds of millions of people worldwide. The hunger crisis is worsening although many efforts have been made to minimize it. Besides that, food waste is one of the critical problems faced by most countries worldwide. It has disrupted the food chain system due to inefficient waste management, while negatively impacting the environment. The majority of the waste is from the food production process, resulting in a net zero production for food manufacturers while also harnessing its potential. Most food production wastes are high in nutritional and functional values, yet most of them end up as low-cost animal feed and plant fertilizers. This review identified key emerging wastes from the production line of mushroom, peanut, and soybean (MPS). These wastes (MPS) provide a new source for food conversion due to their high nutritional content, which contributes to a circular economy in the post-pandemic era and ensures food security. In order to achieve carbon neutrality and effective waste management for the production of alternative foods, biotechnological processes such as digestive, fermentative, and enzymatic conversions are essential. The article provides a narrative action on the critical potential application and challenges of MPS as future foods in the battle against hunger.

Inclusive diets within planetary boundaries

Inclusive diets within planetary boundaries