Variability Of Biological Parameters Research Articles

Understanding rhizospheric microbial dynamics in gladiolus corms through quorum sensing and quorum quenching for disease control and growth promotion

Gladiolus, a widely cultivated cut flower known for its aesthetically pleasing multicoloured spikes, has earned significant commercial popularity. A comprehensive understanding of the rhizosphere bacterial community associated with gladiolus is imperative for revealing its potential benefits. Molecular characterization is considered an effective method to gain insights into the structural and functional aspects of microbial populations. The soil characteristics and bacterial communities in the rhizosphere are typically influenced by quorum sensing (QS) and quorum quenching (QQ) mechanisms. This study aims to explore the niceties and diversity of rhizospheric bacterial populations linked with gladiolus corms, with a specific focus on understanding the dynamics of QS and QQ mechanisms in their complex interactions. The isolation of bacterial strains was achieved through the serial dilution method on nutrient agar (NA) media. The identification of the isolates was accomplished by amplifying 16 S rRNA gene sequences via polymerase chain reaction (PCR) via the use of universal primers. Sequence analysis was conducted via BLAST on the National Center for Biotechnology Information (NCBI) database. The characteristics of the isolated bacteria were elucidated via biosensors. This study identified three QS strains and five QQ strains. A consortium of quenchers was formulated utilizing five strains that demonstrated efficacy in mitigating the impact of disease on gladiolus and fostering growth. Among the three treatments—Scale, Descale, and Descale and Cut Half (DSC)—the DSC treatment emerged as the most effective. This treatment exhibited a broader range of variation in biological parameters over time, aligning with prevailing trends in the local market.

Dynamics of autonomous and nonautonomous Leslie–Gower model for the impacts of fear and its carry‐over effects including predator harvesting

Recently, certain biological field experiments and research findings have revealed that predators not only reduce prey populations through direct predation (lethal effect) but also indirectly affect the growth rate of prey by inducing fear; these nonlethal effects can be carried over seasons or generations. In this paper, we proposed an autonomous and a nonautonomous Leslie–Gower model incorporating some biological factors such as fear and its carry‐over effects, prey refuge, and nonlinear predator harvesting. In the autonomous model, first, we examined the well‐posedness, positivity solutions, and their boundedness. Also, it is shown that new equilibrium points emerge and disappear with the change in intrinsic growth rate of predator. Further, we compute and analyzed the local and global stability at the interior equilibrium points. Furthermore, Hopf bifurcation and direction and stability of limit cycle at interior equilibrium points are established. Moreover, the sensitivity analysis of the biological parameters is carried out numerically with two statistical methods via Latin hypercube sampling and partial rank correlation coefficients. It was found that at the small values of fear factor, carry‐over effect, and refuge behavior of prey parameters, the autonomous system exhibits oscillatory behavior, whereas for small values of prey birth rate and harvesting effort, the system remains stable. However, when intrinsic growth rate of predator increases from a low value to a higher value, the system shows transition from stability to instability and back to stability. We also explore the effects of seasonal variations in biological parameters in the nonautonomous model. Additionally, we investigate the theoretical existence of positive periodic solutions using the continuation theorem. The influences of seasonal variations in some parameters such as prey's birth rate, fear, and its carry‐over effects; refuge behavior of prey; intrinsic growth rate of predator; and harvesting effort are then numerically investigated. The results reveal the emergence of positive periodic solutions and bursting patterns in the seasonally forced model.

Pepper mild mottle virus as an effective tool in microbial source tracking for deficient domestic on-site water treatment systems

Pollution from domestic on-site wastewater treatment systems (OWTS) is a significant contaminant pressure in many rural catchments. However, due to their design, and dispersed proliferation, it is difficult to assess their impact. Water testing methodologies employ bacterial culturing methods and chemical analysis which may lose resolution and/or specificity being confounded by diffuse agricultural sources within a rural environment. In this study, we successfully assessed the applicability of Pepper Mild Mottle Virus (PMMoV) as a human faecal source tracker for deficient on-site wastewater treatment systems. The transport of PMMoV was first studied in the effluent of a 30 cm deep soil column which was dosed for 510 days with primary influent from a conventional septic system. The removal of PMMoV through the 30 cm deep soil column was quantified with a 5-day seeding trial employing primary influent mixed with PMMoV sourced from Tabasco pepper product ®. The trial was then carried out at field scale with the seeding solution dosed into an operational percolation trench receiving septic tank effluent which had been instrumented for porewater sampling. Samples were taken at depths of 10 cm, 30 cm, and 50 cm across the length of the trench at distances of 1 m, 7.5 m, and 17.5 m from the inlet of the trench. PMMoV was detected on all days of the trial, with a peak concentration of 1 × 106 found at the rear of the trench on day 2 of the seeding trial. Finally, to assess the effectiveness of PPMoV as a microbial source tracking tool from a water receptor perspective, three rural catchments with high densities of OWTSs were sampled and analysed for hourly variations in biological parameters which included total coliforms, Escherichia coli, PMMoV, and chemical parameters total organic carbon, total nitrogen, and total carbon. PMMoV was detected in all river samples over a 24-hour period, thereby indicating its suitability as a tracer of human wastewater effluent in such environments with multiple diffuse sources.

The potential for large-scale kelp aquaculture to counteract marine eutrophication by nutrient removal

Large-scale kelp aquaculture offers several opportunities to counteract eutrophication. Here, six sites from Ailian Bay to its offshore waters in Rongcheng, northern China, were selected to investigate the spatiotemporal variations of kelp (Saccharina japonica) and seawater concentrations of C, N, and P in 2017 and 2019 in order to assess nutrient removal by kelp farming. Variations in biological parameters and elemental nutrient concentrations of whole thalli were also quantified in 2015 and 2016. We found that kelp farming in Ailian Bay can remove 1309 tons of C, 104 tons of N, and 12 tons of P. The increase of total suspended matter and nutrient concentrations from the coast to offshore waters supports the hypothesis of nutrient removal by farmed kelp. This study provides evidence of the bioremediation potential of farmed kelp.

Triazophos induced lethal, sub-lethal and transgenerational effects on biological parameters and demographic traits of Pectinophora gossypiella using two sex life table

Pectinophora gossypiella, which destroys cotton crops' brackets, squares, flowers, and bolls, has been identified as a severe pest in practically all the world's cotton-growing nations. Triazophos, a trans-laminar, broad spectrum organophosphate insecticide can manage Lepidopteran pests in cotton, rice, and maize. P. gossypiella has developed resistance against major insecticides including triazophos. To comprehend the function of insecticides in the environment, it is vital to grasp their lethal, low, and/or sublethal impacts as well as transgenerational consequences. In this study, triazohpos had lethal, sublethal, and transgenerational effects in two P. gossypiella generations (F0 and F1). Triazophos caused greater toxicity against P. gossypiella, according to the findings of the bioassay, with LC50 values of 2.728 mg/l for F0 and 1.852 mg/l for F1 after 48 h of exposure. Triazophos LC10 and LC25 concentrations caused considerable variations in biological parameters, which clearly indicated longer larval duration during F0 and F1 generations. Parameters related to reproduction showed significant differences with lower fecundity of 231.08 eggs/ female (LC10); 203.87 eggs/ female (LC25) and 220.95 eggs/ female (LC10) 209.21 eggs/ female (LC25) of F0 and F1 generations respectively and as compared to control which were 264.76 eggs/ female and 274.62 eggs/ female for F0 and F1 respectively. Demographic parameters for F0 and F1 population revealed net reproduction rate (R0); intrinsic rate of increase (r); mean generation time (T) and (λ) were having significant difference in triazophos treated populations as compared to control. From results it can be asserted that life table reproductive and demographic parameters affected by triazophos can be helpful in managing P. gossypiella in cotton crop and will result in more success against triazophos populations of P. gossypiella.

True FRET‐Based Sensing of pH via Separation of FRET and Photon Reabsorption

AbstractFörster resonance energy transfer (FRET)‐based devices have been extensively researched as potential biosensors due to their highly localized responsivity. In particular, dye‐conjugated upconverting nanoparticles (UCNPs) are among the most promising FRET‐based sensor candidates. UCNPs have a multi‐modal emission profile that allows for ratiometric sensing, and by conjugating a biosensitive dye to their surface, this profile can be used to measure localized variations in biological parameters. However, the complex nature of the UCNP energy profile as well as reabsorption of emitted photons must be taken into account in order to properly sense the target parameters. To the authors’ knowledge, no proposed UCNP‐based sensor has accurately taken care of these intricacies. In this article, the authors account for these complexities by creating a FRET‐based sensor that measures pH. This sensor utilizes Thulium (Tm3+)‐doped UCNPs and the fluorescent dye fluorescein isothiocyanate (FITC). It is first demonstrated that photon reabsorption is a serious issue for the 475 nm Tm3+ emission, thereby limiting its use in FRET‐based sensing. It is then shown that by taking the ratio of the 646 and 800 nm emissions rather than the more popular 475 nm one, it is possible to measure pH exclusively through FRET.

Observations on Some Biological Characteristics of Rhipicephalus sanguineus Sensu Lato (Acari: Ixodidae) Under Natural and Laboratory Conditions in Nigeria

Abstract The brown dog tick, Rhipicephalus sanguineus sensu lato (s. l.) is a globally distributed tick of medical and veterinary significance. This study reports some observations on the biological characteristic of the brown dog ticks kept under natural and laboratory conditions in Nigeria. Variation in biological parameters was observed within the Nigerian R. sanguineus s. l. population kept under various conditions. A higher number of R. sanguineus exhibited the type 1 oviposition pattern than the type 2 pattern. The type 1 pattern was observed in 84.2 % and 80 % of R. sanguineus s. l. reared under laboratory and natural conditions, respectively. The pre-oviposition period was significantly shorter in ticks maintained under laboratory conditions than under natural conditions. Similarly, ticks kept under laboratory conditions laid significantly more eggs with higher egg mass weight than ticks kept under natural conditions. Furthermore, the incubation period and the total weight loss by female ticks throughout the oviposition period differed significantly between the two groups (P < 0.05). The engorged R. sanguineus s. l. females kept at 4 °C survived for up to 21 days and remained viable producing fertile eggs. Egg of R. sanguineus s. l. kept at 4 °C for up to 63 days retain viability and were able to hatch to larvae after variable incubation periods when returned to ambient temperatures depending on the duration of storage at 4 °C. The results showed that the tropical lineage of the brown dog tick can survive and remain fecund at low temperatures, suggesting that it can be translocated and established in temperate regions.

Biology and oviposition preference of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on fodder crops and its natural enemies from Central India

The fall armyworm (FAW), Spodoptera frugiperda is a ruinous insect pest, native to tropical and subtropical regions of western hemisphere. It has recently invaded Indian subcontinent during 2018, causing severe damage to crops of several genera of many plant families. The incidence of FAW infestation ranged from 12% to 74%, indicating its establishment in central India where it poses an immediate and significant economic threat to crop production. Phylogenetic analysis revealed that Jhansi, Uttar Pradesh isolate is closely related to the isolates of southern states of India. Studies on biology of FAW indicated no variation in biological parameters, when reared on fodder maize and fodder sorghum, however recorded longer larval and pupal duration (16.07 and 10.00 days) when reared on artificial diet. The adults laid more number of eggs under crop mosaic condition with varied phenological crop growth stages and the fodder maize (782.33 eggs) was most preferred for oviposition. A total of five parasitoids were recovered from the field collected larvae and also predation by generalist predator, Eocanthecona furcellata (Wolff) was recorded during the study period.

Retino-Cortical Mapping Ratio Predicts Columnar and Salt-and-Pepper Organization in Mammalian Visual Cortex

In the mammalian primary visual cortex, neural tuning to stimulus orientation is organized in either columnar or salt-and-pepper patterns across species. For decades, this sharp contrast has spawned fundamental questions about the origin of functional architectures in visual cortex. However, it is unknown whether these patterns reflect disparate developmental mechanisms across mammalian taxa or simply originate from variation of biological parameters under a universal development process. In this work, after the analysis of data from eight mammalian species, we show that cortical organization is predictable by a single factor, the retino-cortical mapping ratio. Groups of species with or without columnar clustering are distinguished by the feedforward sampling ratio, and model simulations with controlled mapping conditions reproduce both types of organization. Prediction from the Nyquist theorem explains this parametric division of the patterns with high accuracy. Our results imply that evolutionary variation of physical parameters may induce development of distinct functional circuitry.

Association of patient-reported outcomes and heart rate trends in heart failure: a report from the Chiron project

Patient-reported outcomes (PROs) have been previously considered “soft” end-points because of the lack of association of the reported outcome to measurable biological parameters. The present study aimed to assess whether electrocardiographic measures are associated to PROs changes. We evaluated the association between heart rate (HR), QRS and QT/QTc durations and PROs, classified as “good” or “bad” according to the patients’ overall feeling of health, in patients from the Chiron project. Twenty-four chronic heart failure (HF) patients were enrolled in the study (71% male, mean age 62.9 ± 9.4 years, 42% ischemic etiology, 15 NYHA class II and 9 class III) providing 1086 days of usable physiological recordings (4 hours/day). The mean HR was significantly higher in the “bad” than in the “good” PROs class (74.0 ± 6.4 bpm vs 68.0 ± 7.2 bpm; p < 0.001). Conversely, the ratio between movement and rest activities showed significantly higher values in “good” compared to “bad” PROs. We also found significantly longer QTc and QRS durations in patients with “bad” PROs compared to patients with “good” PROs. That in patients with mild to moderate HF, higher HR, wider QRS and longer QTc, as well as a reduced HR ratio between movement and rest, were associated with “bad” PROs is clinically noteworthy because the association of worse PROs with measurable variations of biological parameters may help physicians in evaluating PROs reliability itself and in their clinical decisions. Whether a timely intervention on these biological parameters may prevent adverse outcomes is important and deserves to be investigated in further studies.

MRNA Expression and Biomarker Responses in Perch at a Biomonitoring Site in the Baltic Sea – Possible Influence of Natural Brominated Chemicals

Perch (Perca fluviatilis) has been used in biological effect monitoring in a program for integrated coastal fish monitoring at the reference site Kvadofjarden along the Swedish east coast, which is a site characterized by no or minor local anthropogenic influences. Using a set of physiological and biochemical endpoints (i.e., biomarkers), clear time trends for early warning signs of impaired health were noted in the perch from this site, possibly as a result of increased baseline pollution. The data sets also showed relatively large variations among years. To identify additional temporal variation in biological parameters, global mRNA expression studies using RNA sequencing was performed. Perch collected in 2010 and 2014 were selected, as they showed variations in several biomarkers, such as the activity of the detoxification enzyme CYP1A (EROD), the plasma levels of vitellogenin, markers for oxidative stress, white blood cells count and gonad sizes. The RNA sequencing study identified approximately 4800 genes with a significantly difference in mRNA expression levels. A gene ontology enrichment analysis showed that these differentially expressed genes were involved in biological processes such as complement activation, iron ion homeostasis and cholesterol biosynthetic process. In addition, differences in immune system parameters and responses to the exposure of toxic substances have now been verified in two different biological levels (mRNA and protein) in perch collected in 2010 and 2014. Markedly higher mRNA expression of the membrane transporter (MATE) and the detoxification enzyme COMT, together with higher concentrations of bioactive naturally produced brominated compounds, such as brominated indoles and carbazoles, seem to indicate that the perch collected in 2014 had been exposed to macro- and microalga blooming to a higher degree than did perch from 2010. These results and the differential mRNA expression between the 2 years in genes related to immune and oxidative stress parameters suggest that attention must be given to algae blooming when elucidating the well-being of the perch at Kvadofjarden and other Baltic coastal sites.

Beneficial role of quinoa and Nigella sativa seeds as antihyperuricemia in rats

Tsativa seeds (NSS) and their combination on hyperuricemia. Thirty male albino rats assigned to five groups (n=6). The first these fed on the standard diet as normal control rats. The other rats (n=24), received a basal diet including a 20g /kg diet potassium oxonate to create hyperuricemia. Then ill rats divided into four groups. The hyperuricemic control group and three groups treated with added to their diet 10% QS; 4% NSS and mix from10% QS plus 4%NSS respectively. After that, the researcher calculated the biological status and estimated biochemical analysis. The results appear that high uric acid groups, in which feeding remedy diets showed no significant variation in biological parameters compared with the normal rats. The same groups indicated a significant improvement in renal function when compared with the injury group. Likewise, rising kidney tissues antioxidant status “superoxide dismutase; catalase and glutathione transferase and decrease malondialdehyde and interleukin-1 (IL-6). Also, the mixture diet increased antioxidant activity. This study concluded that QS and NSS may improve kidney function and may reduce oxidative stress. This article recommended that special meals of hyperuricemic patients supplemented by a blend of QS and NSS.

A stochastic bio-economic pig farm model to assess the impact of innovations on farm performance

Recently developed innovations may improve the economic and environmental sustainability of pig production systems. Generic models are needed to assess the impact of innovations on farm performance. Here we developed a stochastic bio-economic farm model for a typical farrow-to-finish pig farm to assess the impact of innovations on private and social profits. The model accounts for emissions of greenhouse gases from feed production and manure by using the shadow price of CO2, and for stochasticity of economic and biological parameters. The model was applied to assess the impact of using locally produced alternative feed sources (i.e. co-products) in the diets of finishing pigs on private and social profits of a typical Brazilian farrow-to-finish pig farm. Three cases were defined: a reference case (with a standard corn–soybean meal-based finishing diet), a macaúba case (with a macaúba kernel cake-based finishing diet) and a co-products case (with a co-products-based finishing diet). Pigs were assumed to be fed to equal net energy intakes in the three cases. Social profits are 34% to 38% lower than private profits in the three cases. Private and social profits are about 11% and 14% higher for the macaúba case than the reference case, whereas they are 3% and 7% lower for the co-products case, respectively. Environmental costs are higher under the alternative cases than the reference case suggesting that other benefits (e.g. costs and land use) should be considered to utilize co-products. The CV of farm profits is between 75% and 87% in the three cases following from the volatility of prices over time and variations in biological parameters between fattening pigs.

Variability of biological parameters of Colorado potato beetle development at evaluation of Solanaceous cultivars for resistance in different ecological conditions

Variability of biological parameters of Colorado potato beetle development at evaluation of Solanaceous cultivars for resistance in different ecological conditions

Fewer eggs from larger size limits: counterintuitive outcomes in a spatially heterogeneous fishery

Abstract The legal minimum length (LML) of female Southern Rock Lobster (Jasus edwardsii) was reduced in the Tasmanian fishery in 1966 for higher sustainable catches. Originally, the LML was to be reduced in slow growth southern areas only; however, the change was implemented across the entire fishery due to lobbying by commercial fishers. The lower LML has been controversial ever since, including during recent years when low recruitment resulted in a lower total allowable catch (TAC). Fishers argued that this could have been prevented with a higher female LML across the jurisdiction. A length- and sex-based bioeconomic model was used to examine probable outcomes of the larger statewide LML. This model showed that management of egg production would be poorly served by raising the statewide LML because of spatial patterns in the stock and fishery. Catch would be displaced from areas where egg production was already high and into the most depleted areas thus reducing production in areas of greatest concern. Spatial variation in biological parameters can have a profound effect on outcomes of management perceived to be conservative, possibly leading to negative impacts. This risk exists wherever catch is displaced, such as with Marine Protected Areas, spatial TACs and gear restrictions.

SU-E-T-146: Effects of Uncertainties of Radiation Sensitivity of Biological Modelling for Treatment Planning

Purpose: The aim of this study was to evaluate the distribution of uncertainty of cell survival by radiation, and assesses the usefulness of stochastic biological model applying for gaussian distribution. Methods: For single cell experiments, exponentially growing cells were harvested from the standard cell culture dishes by trypsinization, and suspended in test tubes containing 1 ml of MEM(2x106 cells/ml). The hypoxic cultures were treated with 95% N2−5% CO2 gas for 30 minutes. In vitro radiosensitization was also measured in EMT6/KU single cells to add radiosensitizer under hypoxic conditions. X-ray irradiation was carried out by using an Xray unit (Hitachi X-ray unit, model MBR-1505R3) with 0.5 mm Al/1.0 mm Cu filter, 150 kV, 4 Gy/min). In vitro assay, cells on the dish were irradiated with 1 Gy to 24 Gy, respectively. After irradiation, colony formation assays were performed. Variations of biological parameters were investigated at standard cell culture(n=16), hypoxic cell culture(n=45) and hypoxic cell culture(n=21) with radiosensitizers, respectively. The data were obtained by separate schedule to take account for the variation of radiation sensitivity of cell cycle. Results: At standard cell culture, hypoxic cell culture and hypoxic cell culture with radiosensitizers, median and standard deviation of alpha/beta ratio were 37.1±73.4 Gy, 9.8±23.7 Gy, 20.7±21.9 Gy, respectively. Average and standard deviation of D5 0 were 2.5±2.5 Gy, 6.1±2.2 Gy, 3.6±1.3 Gy, respectively. Conclusion: In this study, we have challenged to apply these uncertainties of parameters for the biological model. The variation of alpha values, beta values, D5 0 as well as cell culture might have highly affected by probability of cell death. Further research is in progress for precise prediction of the cell death as well as tumor control probability for treatment planning.

Variance-based sensitivity analysis of biological uncertainties in carbon ion therapy

PurposeBiological models to estimate the relative biological effectiveness (RBE) or the equivalent dose in 2 Gy fractions (EQD2) are needed for treatment planning and plan evaluation in carbon ion therapy. We present a model-independent, Monte Carlo based sensitivity analysis (SA) approach to quantify the impact of different uncertainties on the biological models. Methods and materialsThe Monte Carlo based SA is used for the evaluation of variations in biological parameters. The key property of this SA is the high number of simulation runs, each with randomized input parameters, allowing for a statistical variance-based ranking of the input variations. The potential of this SA is shown in a simplified one-dimensional treatment plan optimization. Physical properties of carbon ion beams (e.g. fragmentation) are simulated using the Monte Carlo code FLUKA. To estimate biological effects of ion beams compared to X-rays, we use the Local Effect Model (LEM) in the framework of the linear-quadratic (LQ) model. Currently, only uncertainties in the output of the biological models are taken into account. Results/conclusionsThe presented SA is suitable for evaluation of the impact of variations in biological parameters. Major advantages are the possibility to access and display the sensitivity of the evaluated quantity on several parameter variations at the same time. Main challenges for later use in three-dimensional treatment plan evaluation are computational time and memory usage. The presented SA can be performed with any analytical or numerical function and hence be applied to any biological model used in carbon ion therapy.

Seasonal variations of phytoplankton species in L ake V ictoria and the influence of iron and zinc ions on the dominant species identified during 2006–2007 studies

The current study was conducted for 2 years (2006 and 2007) during January, April and September to investigate seasonal variations in biological parameters and planktonic biodiversity observed at four sampling sites (MRM, M500, SRM and S500) in Lake Victoria. Blue-green algae (Cyanophyta) dominated the lakeshore waters of Lake Victoria, comprising 54.1% of the total algal content, compared to 24.4% for diatoms and 14.7% for green algae (Chlorophyta). Euglenophytes and dinoflagellates both constitute <10% of the algal biomass. The algal distribution at the Sango Bay sampling sites, however, is different in that it is dominated by diatoms, in contrast to Murchison Bay, which was dominated by blue-green algae. This study also investigated the influence of iron (Fe2+and Fe3+) and zinc (Zn2+) ions on four strains of microcystis (CYN 464, CYN 465, CYN 478 and CYN 522) isolated from Murchison Bay in Lake Victoria. The suggestion that iron species and zinc ions might limit phytoplankton growth in Lake Victoria was tested by enriching algal culture media with different metal concentrations. Based on measurements of the algal biomass of four species of Lake Victoria, the algal biomass of the four microcystis strains generally decreased with increased zinc and Fe2+ concentrations. The algal biomass of the four strains, however, increased with increased Fe3+ concentrations. This response to different metal concentrations provides evidence that high Zn2+ and Fe2+ ion concentrations limit phytoplankton growth and species distribution. The availability of Fe3+ ions is an important selective force on Lake Victoria phytoplankton communities.

A model for estimating how variability of biological parameters affects economic factors in an integrated turkey farm

Turkeys, as well as other poultry meat, are marketed as a healthier alternative to red meat. At the same time, the necessary investment in integrated turkey projects is 65% higher than for similar broiler projects. This explains the importance of rigorous evaluation of new turkey farms, including their sensitivity to biological parameters. We present a method of evaluating poultry projects that takes simultaneous variability of several biological parameters into account, using a bio-economic model, stochastic simulation, and an integrated turkey farm in Russia as a real-life example. The algorithm based on the Cholesky decomposition of the covariance matrix was used to generate a multivariate normal random vector of biological parameters. The bio-economic model takes into account simultaneous variability of major input biological parameters related to all stages of an integrated poultry farm: survival, hatchability, ratio of carcass weight to live weight, and number of eggs per layer. The highest variability of the output economic indices was estimated for internal rate of return: the coefficient of variation (CV) of this major economic index was approximately 240% of the CV of the input biological parameters. Such estimation can be used to analyze a project's economic risks, i.e., variability in production cost and profitability.

A Model for Estimating How Variability of Biological Parameters Affects Economic Factors in an Integrated Turkey Farm

Turkey meat is marketed as a healthier alternative to red meat but the necessary investment in integrated turkey projects is 65% higher than for similar broiler projects. This explains the importance of rigorous evaluation of new turkey farms, including their sensitivity to biological parameters. We present a method of evaluating poultry projects that takes simultaneous variability of several biological parameters into account, using a bio-economic model, stochastic simulation, and an integrated turkey farm in Russia as a real-life example. The algorithm based on the Cholesky decomposition of the covariance matrix was used to generate a multivariate normal random vector of biological parameters. The bio-economic model takes into account simultaneous variability of major input biological parameters related to all stages of an integrated poultry farm: survival, hatchability, ratio of carcass weight to live weight, and number of eggs per layer. The variability of the output economic indices was indicated by coefficients of variation (CV) which were 100-108% of the CV of the biological parameter, for production cost, and 163-168% for project profitability. Such an estimation can be used to analyze a project’s economic risks, i.e., variability in production cost and profitability.