Compensatory Growth and Fat Parameters on Broiler Fasted in Early Life

The experiment was carried out to investigate the effect of feed withholding in the very early life ofbird on its compensatory growth capacity and fat parameters. A total of 60 mixed-sexes of one day oldRoss chicks were used in the experiment conducted with completely randomized design of 2 differentfeeding times after hatching, i.e.: T1: given access to feed and water ad libitum immediately afterhatching until 35d of age; and T2: withheld from feed (fasted) but not from water for 48h after hatchingand then fed ad libitum until d35. The birds were weighed at the start of experiment and weeklythereafter, and DWG was then calculated. Feed intakes and FCR were also recorded weekly. At d36,abdominal fat was taken out from 2 birds per pen and was weighed. Breast meat (skinless) from thesame birds was also sampled for total FA analysis. Final BW (d35) and total feed consumption of earlyfastedbirds were 1935.17±43.90 kg and 2745.55±47.48 kg and those of unfasted birds were2019.00±50.85 kg and 2910.84±128.10 kg, respectively. FCR of early-fasted and unfasted birds at d35were 1.42±0.03 and 1.45±0.07. The magnitude difference of DWG between early-fasted and unfastedbirds was 27% at d7, whereas at d35 the difference was only 4.5%. Abdominal fat percentage to live BWof early-fasted birds was 1.65±0.09% (male) and 1.60±0.10% (female) and that of unfasted birds was2.00±0.19% (male) and 1.89±0.38% (female). Total FA contained in meat of early-fasted and unfastedbirds were 0.82±0.10 and 0.85±0.10 g/100gDM. Overall, BW and feed consumption of early-fastedbirds were significantly lower (P0.05) between early-fasted and unfasted birds. Inconclusion, holding birds without feed following hatch (under practical conditions) may limit thecompensatory growth capacity of birds in the later age. Fasting applied in the very early life of broilerleads to impairment of cell hyperplasia resulting in permanent stunting. Abdominal fat and total FAcontained in meat might not be affected by fasting for 48h after hatching. The degree or duration of feedwithholding (for 48h after hatching) might not sufficient to reduce adipocyte proliferation or the numberof precursor adipocytes

Bayesian multi-QTL mapping for growth curve parameters

Background Identification of QTL affecting a phenotype which is measured multiple times on the same experimental unit is not a trivial task because the repeated measures are not independent and in most cases show a trend in time. A complicating factor is that in most cases the mean increases non-linear with time as well as the variance. A two- step approach was used to analyze a simulated data set containing 1000 individuals with 5 measurements each. First the measurements were summarized in latent variables and subsequently a genome wide analysis was performed of these latent variables to identify segregating QTL using a Bayesian algorithm. Results For each individual a logistic growth curve was fitted and three latent variables: asymptote (ASYM), inflection point (XMID) and scaling factor (SCAL) were estimated per individual. Applying an 'animal' model showed heritabilities of approximately 48% for ASYM and SCAL while the heritability for XMID was approximately 24%. The genome wide scan revealed four QTLs affecting ASYM, one QTL affecting XMID and four QTLs affecting SCAL. The size of the QTL differed. QTL with a larger effect could be more precisely located compared to QTL with small effect. The locations of the QTLs for separate parameters were very close in some cases and probably caused the genetic correlation observed between ASYM and XMID and SCAL respectively. None of the QTL appeared on chromosome five. Conclusions Repeated observations on individuals were affected by at least nine QTLs. For most QTL a precise location could be determined. The QTL for the inflection point (XMID) was difficult to pinpoint and might actually exist of two closely linked QTL on chromosome one

Estimation of the growth curve parameters in Macrobrachium rosenbergii

Growth is one of the most important characteristics of cultured species. The objective of this study was to determine the fitness of linear, log linear, polynomial, exponential and Logistic functions to the growth curves of Macrobrachium rosenbergii obtained by using weekly records of live weight, total length, head length, claw length, and last segment length from 20 to 192 days of age. The models were evaluated according to the coefficient of determination (R2), and error sum off square (ESS) and helps in formulating breeders in selective breeding programs. Twenty full-sib families consisting 400 PLs each were stocked in 20 different hapas and reared till 8 weeks after which a total of 1200 animals were transferred to earthen ponds and reared up to 192 days. The R2 values of the models ranged from 56 – 96 in case of overall body weight with logistic model being the highest. The R2 value for total length ranged from 62 to 90 with logistic model being the highest. In case of head length, the R2 value ranged between 55 and 95 with logistic model being the highest. The R2 value for claw length ranged from 44 to 94 with logistic model being the highest. For last segment length, R2 value ranged from 55 – 80 with polynomial model being the highest. However, the log linear model registered low ESS value followed by linear model for overall body weight while exponential model showed low ESS value followed by log linear model in case of head length. For total length the low ESS value was given by log linear model followed by logistic model and for claw length exponential model showed low ESS value followed by log linear model. In case of last segment length, linear model showed lowest ESS value followed by log linear model. Since, the model that shows highest R2 value with low ESS value is generally considered as the best fit model. Among the five models tested, logistic model, log linear model and linear models were found to be the best models for overall body weight, total length and head length respectively. For claw length and last segment length, log linear model was found to be the best model. These models can be used to predict growth rates in M. rosenbergii. However, further studies need to be conducted with more growth traits taken into consideratio

Pharmacodynamic modelling of in vitro activity of tetracycline against a representative, naturally occurring population of porcine Escherichia coli

Background The complex relationship between drug concentrations and bacterial growth rates require not only the minimum inhibitory concentration but also other parameters to capture the dynamic nature of the relationship. To analyse this relationship between tetracycline concentration and growth of Escherichia coli representative of those found in the Danish pig population, we compared the growth of 50 randomly selected strains. The observed net growth rates were used to describe the in vitro pharmacodynamic relationship between drug concentration and net growth rate based on E max model with three parameters: maximum net growth rate (α max ); concentration for a half-maximal response (E max ); and the Hill coefficient (γ). Results The net growth rate in the absence of antibiotic did not differ between susceptible and resistant isolates (P = 0.97). The net growth rate decreased with increasing tetracycline concentrations, and this decline was greater in susceptible strains than resistant strains. The lag phase, defined as the time needed for the strain to reach an OD 600 value of 0.01, increased exponentially with increasing tetracycline concentration. The pharmacodynamic parameters confirmed that the αmax between susceptible and resistant strains in the absence of a drug was not different. EC 50 increased linearly with MIC on a log–log scale, and γ was different between susceptible and resistant strains. Conclusions The in vitro model parameters described the inhibition effect of tetracycline on E. coli when strains were exposed to a wide range of tetracycline concentrations. These parameters, along with in vivo pharmacokinetic data, may be useful in mathematical models to predict in vivo competitive growth of many different strains and for development of optimal dosing regimens for preventing selection of resistance

Regional Economic Policy: Structured Approach and Tools (The Oretical Formulation

The subject matter of the article is the development of a doctrine of coordinated regional development and the study of the structural quality of development of regional systems based on the theoretical analysis of institutional factors (parameters) that determine the technological efficiency of the regional economy. The purpose is to show possibilities of technological changes and the shift of economic growth in a particular regional system, with strict limits for accelerated development, with emphasis on industrial regions. For this purpose, we generated a number of structural models, analyzed the impact of technological factors on parameters of growth of the regional economy and determined conditions for development of industrial regions. We applied correlative and regression analysis to establish a statistically significant correlation between relevant parameters, used econometric models to show the possibility to estimate parameters of growth through control parameters, including technological factor. The structural aspect of regional economic growth is measured by dividing investments into two classes: old and new technologies. It is possible to increase the technological efficiency of the regional economy by improving results with regard to used (old) technologies and applying new technologies. This approach fundamentally refines the priority queue algorithm for regional development, provides a choice of a strategy of regional technological development. When resources are directed only to the latest technologies, the disproportion in development of the regional economic system can dramatically increase, and parameters related to diversion of resources and creation of a new resource will determine the growth rate of the region. The behavior of investment in old technologies has a major impact on the rate of regional economic growth in Russia, while investments in new technologies are minor and did not have an equivalent impact on the economic growth rate compared with old technologies. Institutional corrections that define parameters of resource diversion from old technologies and creation of a new resource for development, will determine the quality of new economic growth

Growth parameters of InAs/GaAs quantum dots grown by MOVPE

Quantum dots are zero dimensional structures and therefore have superior transport and optical properties compared to either 2-dimensional or 3-dimensional structures. Quantum dots show promise for use in diode lasers, amplifiers, and biological sensors. They are also vigorously researched for use in solid-state quantum computing. Indium arsenide quantum dots are currently studied for their use in the photoelectronic and semiconductor fields. In our research, Indium Arsenide (InAs) quantum dots are grown on Gallium Arsenide (GaAs) substrate using Metal Organic Vapor Phase Epitaxy (MOVPE) in the Stranski-Krastanov Growth mode. Several parameters influence the growth of InAs quantum dots greatly. We will be describing these growth parameters, which we have identified in our current growth attempts. We are currently trying to achieve device quality InAs/GaAs quantum dots by varying these parameters we have identified. These growth parameters include the V/III ratio of both InAs and GaAs, In/As growth temperature, and quantum dot growth time. By carefully fine tuning the parameters above, we will be able to grow device quality quantum dots. Deviations from the optimized value will result in either no formation of quantum dots, or the formation of large islands which are particularly susceptible to dislocations. The effects of differing growth parameters are observed by using an Atomic Force Microscope (AFM) located at Faculty of Science, UTM. The MOVPE is located at Ibn Sina Institute for Fundamental Science Studies, UTM

Estimation of the parameters of a stochastic logistic growth model

We consider a stochastic logistic growth model involving both birth and death rates in the drift and diffusion coefficients for which extinction eventually occurs almost surely. The associated complete Fokker-Planck equation describing the law of the process is established and studied. We then use its solution to build a likelihood function for the unknown model parameters, when discretely sampled data is available. The existing estimation methods need adaptation in order to deal with the extinction problem. We propose such adaptations, based on the particular form of the Fokker-Planck equation, and we evaluate their performances with numerical simulations. In the same time, we explore the identifiability of the parameters which is a crucial problem for the corresponding deterministic (noise free) model

Engineering the side facets of vertical [100] oriented InP nanowires for novel radial heterostructures

In addition to being grown on industry-standard orientation, vertical [100] oriented nanowires present novel families of facets and related cross-sectional shapes. These nanowires are engineered to achieve a number of facet combinations and cross-sectional shapes, by varying their growth parameters within ranges that facilitate vertical growth. In situ post-growth annealing technique is used to realise other combinations that are unattainable solely using growth parameters. Two examples of possible novel radial heterostructures grown on these vertical [100] oriented nanowire facets are presented, demonstrating their potential in future applications

Simulation of spherulite growth using a comprehensive approach to modeling the first-order isotropic/smectic-A mesophase transition

A comprehensive modeling and simulation study of the first-order isotropic/smectic-A transition is presented and applied to phase diagram computation and two-dimensional spherulite growth. An approach based on nonlinear optimization, that incorporates experimental data (from 12CB, dodecyl-cyanobiphenyl), is used to determine physically realistic model parameters. These parameters are then used in conjunction with an optimized phase diagram computation method. Additionally, a time-dependent formulation is presented and applied to the study of two-dimensional smectic-A spherulite growth. These results show the growth kinematics and defect dynamics of nanoscale smectic-A spherulite growth in an isotropic phase with an initially radial layer configuration