A meta-analysis of responses to dietary nonphytate phosphorus and phytase in laying hens

Reducing the level of nonphytate P (NPP) in diets for laying hens without negatively affecting their productivity and heath is crucial for sustainable egg production. A meta-analytical approach using a full quadratic model was applied to quantify relationships between dietary NPP and phytase levels and performance of laying hens. Egg production (EP, %), egg mass (EM, g/hen/day), and feed conversion ratio (FCR) were considered as model outputs. A data set containing 168 P or P plus phytase treatments was extracted from 12 published papers. The data were assembled from 14 trials with a total of 8,752 hens in the range of 36 to 76 wk of age. The EP, EM, and FCR were analyzed using a linear mixed model that included the linear and quadratic effects of dietary NPP and phytase levels and their interactions. Except for the quadratic effect of dietary phytase on FCR, all other model components (that is, intercept, linear, quadratic, and interactions) were significant (P<0.05). There was a relatively strong relationship between observed and predicted EP (R2=0.78, RMSE=3.73), EM (R2=0.84, RMSE=2.09), and FCR (R2=0.78, RMSE=0.11), demonstrating that observations within study are practically predictable. Analyses of the model revealed that corn-soybean meal-based diets containing 0.22% of NPP without supplemental phytase resulted in high EP, EM, and feed efficiency in layers. In the presence of 150, 300, and 400 phytase units (FTU)/kg of feed, the dietary NPP level may be decreased and optimal levels were calculated as 0.18, 0.15, and 0.14%, respectively.

Immobilization of Pichia pastoris cells containing alcohol oxidase activity

BACKGROUND AND OBJECTIVES

The attempts were made to describe the development of a whole cell immobilization of P. pastoris by entrapping the cells in polyacrylamide gel beads. The alcohol oxidase activity of the whole cell Pichia pastoris was evaluated in comparison with yeast biomass production.

MATERIALS AND METHODS

Methylotrophic yeast P. pastoris was obtained from Collection of Standard Microorganisms, Department of Bacterial Vaccines, Pasteur Institute of Iran (CSMPI). Stock culture was maintained on YPD agar plates. Alcohol oxidase was strongly induced by addition of 0.5% methanol as the carbon source. The cells were harvested by centrifugation then permeabilized. Finally the cells were immobilized in polyacrylamide gel beads. The activity of alcohol oxidase was determined by method of Tane et al.

RESULTS

At the end of the logarithmic phase of cell culture, the alcohol oxidase activity of the whole cell P. Pastoris reached the highest level. In comparison, the alcohol oxidase activity was measured in an immobilized P. pastoris when entrapped in polyacrylamide gel beads. The alcohol oxidase activity of cells was induced by addition of 0.5% methanol as the carbon source. The cells were permeabilized by cetyltrimethylammonium bromide (CTAB) and immobilized. CTAB was also found to increase the gel permeability. Alcohol oxidase activity of immobilized cells was then quantitated by ABTS/POD spectrophotometric method at OD (420.) There was a 14% increase in alcohol oxidase activity in immobilized cells as compared with free cells. By addition of 2-butanol as a substrate, the relative activity of alcohol oxidase was significantly higher as compared with other substrates added to the reaction media.

CONCLUSION

Immobilization of cells could eliminate lengthy and expensive procedures of enzyme separation and purification, protect and stabilize enzyme activity, and perform easy separation of the enzyme from the reaction media.

Prediction of the true digestible amino acid contents from the chemical composition of sorghum grain for poultry

Accurate knowledge of true digestible amino acid (TDAA) contents of feedstuffs is necessary to accurately formulate poultry diets for profitable production. Several experimental approaches that are highly expensive and time consuming have been used to determine available amino acids. Prediction of the nutritive value of a feed ingredient from its chemical composition via regression methodology has been attempted for many years. The artificial neural network (ANN) model is a powerful method that may describe the relationship between digestible amino acid contents and chemical composition. Therefore, multiple linear regressions (MLR) and ANN models were developed for predicting the TDAA contents of sorghum grain based on chemical composition. A precision-fed assay trial using cecectomized roosters was performed to determine the TDAA contents in 48 sorghum samples from 12 sorghum varieties differing in chemical composition. The input variables for both MLR and ANN models were CP, ash, crude fiber, ether extract, and total phenols whereas the output variable was each individual TDAA for every sample. The results of this study revealed that it is possible to satisfactorily estimate the TDAA of sorghum grain through its chemical composition. The chemical composition of sorghum grain seems to highly influence the TDAA contents when considering components such as CP, crude fiber, ether extract, ash and total phenols. It is also possible to estimate the TDAA contents through multiple regression equations with reasonable accuracy depending on composition. However, a more satisfactory prediction may be achieved via ANN for all amino acids. The R(2) values for the ANN model corresponding to testing and training parameters showed a higher accuracy of prediction than equations established by the MLR method. In addition, the current data confirmed that chemical composition, often considered in total amino acid prediction, could be also a useful predictor of true digestible values of selected amino acids for poultry.

Response surface and neural network models for performance of broiler chicks fed diets varying in digestible protein and critical amino acids from 11 to 17 days of age

Central composite design (CCD; 5 levels and 4 factors), response surface methodology (RSM), and artificial neural network-genetic algorithm (ANN-GA) were used to evaluate the response of broiler chicks [ADG and feed conversion ratio (FCR)] to dietary standardized ileal digestible protein (dP), lysine (dLys), total sulfur amino acids (dTSAA), and threonine (dThr). A total of 84 battery brooder units of 5 birds each were assigned to 28 diets of CCD containing 5 levels of dP (18-22%), dLys (1.06-1.30%), dTSAA (0.81-1.01%), and dThr (0.66-0.86%) from 11 to 17 d of age. The experimental results of CCD were fitted with the quadratic and artificial neural network models. A ridge analysis (for RSM models) and a genetic algorithm (for ANN-GA models) were used to compute the optimal response for ADG and FCR. For both ADG and FCR, the goodness of fit in terms of R(2) and MS error corresponding to ANN-GA and RSM models showed a substantially higher accuracy of prediction for ANN models (ADG model: R(2) = 0.99; FCR model: R(2) = 0.97) compared with RSM models (ADG model: R(2) = 0.70; FCR model: R(2) = 0.71). The ridge maximum analysis on ADG and minimum analysis on FCR models revealed that the maximum ADG may be obtained with 18.5, 1.10, 0.89, and 0.73% dP, dLys, dTSAA, and dThr, respectively, in diet, and minimum FCR may be obtained with 19.44, 1.18, 0.90, and 0.75% of dP, dLys, dTSAA, and dThr, respectively, in diet. The optimization results of ANN-GA models showed the maximum ADG may be achieved with 19.93, 1.06, 0.90, and 0.76% of dP, dLys, dTSAA, and dThr, respectively, in diet, and minimum FCR may be achieved with 18.63, 1.26, 0.84, and 0.69% of dP, dLys, dTSAA, and dThr, respectively, in diet. The results of this study revealed that the platform of CCD (for conducting growth trials with minimum treatments), RSM model, and ANN-GA (for experimental data modeling and optimization) may be used to describe the relationship between dietary nutrient concentrations and broiler performance to achieve the optimal target.

Laparatomy due to gastrointestinal complications after open heart surgery

AIM

Abdominal complications following open heart surgery remain rare but fatal events with mortality rates of 14.5% up to 100%. Manifestations and managements of these complications are varying. Approximately, 25% of patients with gastrointestinal complications require surgical management with obviously higher mortality risks. The aim of this study was to determine the perioperative prognostic factors of gastrointestinal complications with surgical consequences after cardiac surgery.

METHODS

The study enrolled 15.737 patients who underwent open heart surgery between January 2002 and September 2007. Sixteen (0.1%) persons required laparatomy due to postoperative gastrointestinal complications. Additionally, the preoperative, operative, and postoperative risk factors for this condition were studied.

RESULTS

Among the patients enrolled, 15.737 patients underwent open heart surgery while 16 (0.1%) required laparatomy procedures due to gastrointestinal complications. They were comprised of 11 (68.8%) men and 5 (31.3%) women at a mean age of 62.88±12.56 years. There was a history of hypertension in 9 (56.3%) patients, hypercholesterolemia in 11 (68.8%), renal failure in 4 (25%), previous CABG in 2 (12.5%) and PTCA in 2 (12.5%). Morbidity and mortality were significantly higher in this group of patients with a mortality rate of 68.8% (68.8% versus 1.6%).

CONCLUSION

Our multivariate logistic regression model identified the following parameters to be the prognostic factors for gastrointestinal complications with surgical consequences: a history of previous CABG, previous PTCA, preoperative renal failure, preoperative anticoagulant agent use, valve surgery, combined valve and CABG surgery, and intra-aortic balloon pump requirement with OR of 51.95, 4.623, 26.436, 0.140, 5.43, 11.469 and 3.76, respectively.

Tracing fine sediment sources in small mountain catchment

Fine sediment represents an important diffuse source pollutant in surface waters, due to its role in governing the transfer and fate of many substances, including nutrients, heavy metals, pesticides and other organic contaminants, and its influence on aquatic ecology. Therefore, catchment management strategies frequently need to include provision for the control of sediment mobilization and delivery. The sediment tracing concept provides a valuable framework for assisting the management and control of diffuse source sediment pollution by identifying the key sources and demonstrating the importance of intermediate storages and the likely impact of upstream mitigation strategies on downstream sediment and sediment associated contaminant fluxes. In this research, fine sediment sources were identified using tracing method. By field works, sediments were sampled from dam reservoir, different sources were also sampled. Fifteen tracers were first selected for tracing which are: The amounts of N, P, C, Cr, Co, Mg, K, Na, smectite, chlorite, illite, kaolinite, and two magnetic properties consisting of LOW Frequency Magnetic Susceptibility (X(LF)) and Frequency Dependent Magnetic Susceptibility (X(FD)). The samples were analyzed in the laboratory for these parameters and different statistical methods were applied to the data including Non-parametric Kruskal-Wallis Test and Stepwise Discriminant function analysis. The results provide important information on the relative importance of fine sediment sources to the reservoir sediments, which can be used to support model validation and the targeting of management and control strategies.

The integration of broiler chicken threonine responses data into neural network models

In making general recommendations for amino acids, researchers might survey various published data on the responses of poultry to amino acids. In this way, the use of appropriate mathematical and statistical approaches may help researchers draw appropriate conclusions. The purpose of this study was to develop artificial neural network (ANN)-based models to analyze data on the responses of broiler chickens [ADG and feed conversion ratio (FCR)] to protein and threonine from 21 to 42 d of age. A data set containing 92 dose-response treatments was extracted from the literature, compiled, and entered into the training and testing sets of the ANN models. The constructed models were subjected to a process of sensitivity analysis to evaluate the relative importance of the effects of dietary protein and threonine on ADG and FCR. Optimal values for the input variables (protein and threonine requirements) to maximize ADG and minimize FCR in birds were obtained by using the ANN models with an optimization algorithm. Based on the calculated goodness of fit criteria, it appeared that the platform of ANN-based models with the sensitivity analysis and optimization algorithms was an efficient tool for integrating published data on the responses of broiler chickens to threonine. The analyses of ANN models for ADG and FCR based on the compiled data set suggested that the dietary protein concentration was more important than the threonine concentration. The optimization algorithm revealed that diets containing 18.69% protein and 0.73% threonine could lead to optimal ADG, whereas the optimal FCR could be achieved with diets containing 18.71% protein and 0.75% threonine.

Plasma adiponectin concentration and insulin resistance: role of successful kidney transplantation

Adiponectin (ADPN) has been reported to be inversely correlated with insulin resistance (IR) in uremic subjects and following kidney transplantation. Kidneys have been suggested to play a part in ADPN clearance. This study sought to evaluate this hypothesis. We enrolled 67 candidates with end-stage renal disease (ESRD) along with 30 healthy unrelated donors. Plasma ADPN, IR (based on the homeostasis model assessment for IR index), and glomerular filtration rates were compared between control and patient groups. The correlations of the aforementioned variables were also compared in the patient group 1 day before and 14 days following transplantation. The changes in measured parameters were also compared with control group values. The glomerular filtration rate was significantly decreased among recipients. ADPN levels were remarkably higher in the patient group before transplantation when compared with healthy subjects (P<.001) and remained significantly higher thereafter (P<.001). Insulin resistance was higher, albeit not significantly, among ESRD patients compared with controls (P>.05) and it increased following transplantation (P=.03). There was no correlation between ADPN, IR, and glomerular filtration rate in normal individuals or ESRD patients before or after transplantation. It is our assumption that mechanisms other than kidney function are probably involved in ADPN metabolism in ESRD patients and in the immediate phase following transplantation. It does not seem that ADPN substantially affects IR either in ESRD or transplantation patients.

Serotyping and Cross-Reactivity's Between Different Pseudomonas aeruginosa Isolates Prevalent in Iran

BACKGROUND AND OBJECTIVES

300 Pseudomonas aeruginosa strains were isolated from hospitalized patients in Iran. Using international antigenic typing system (IATS) antibodies, all strains were classified into 16 serotypes while serotype 14 was not identified among the 17 known serotypes. To evaluate the rate of cross-reactivity between O- antigenic determinants, monospecific polyclonal antibodies were made against whole-killed-cells and live cells of each serotype.

MATERIALS AND METHODS

Each antiserum was challenged against homologous and heterologous antigens using slide agglutination test. The degree of agglutination reaction is shown by -ve, 1+ve, 2+ve, 3+ve and 4+ve for 0, 25%, 50%, 75% and 100% agglutination respectively. Then, the results were tabulated for further study.

RESULTS

The rate of cross-reactivity between O-antigenic determinants demonstrated that strains 10.55 and 15.14 had the highest agglutination reaction with serum of all the homologous and heterologous serotypes.

CONCLUSION

Evaluation of the results obtained from the present study can be applied in production of reliable vaccines and antisera as therapeutic agents or as diagnostic kits.

Predicting caloric and feed efficiency in turkeys using the group method of data handling-type neural networks

Neural networks (NN) are a relatively new option to model growth in animal production systems. One self-organizing submodel of artificial NN is the group method of data handling (GMDH)-type NN. The use of such self-organizing networks has led to successful application of the GMDH algorithm over a broad range of areas in engineering, science, and economics. The present study aimed to apply the GMDH-type NN to predict caloric efficiency (CE, g of gain/kcal of caloric intake) and feed efficiency (FE, kg of gain/kg of feed intake) in tom and hen turkeys fed diets containing different energy and amino acid levels. Involved effective input parameters in prediction of CE and FE were age, dietary ME, CP, Met, and Lys. Quantitative examination of the goodness of fit for the predictive models was made using R2 and error measurement indices commonly used to evaluate forecasting models. Statistical performance of the developed GMDH-type NN models revealed close agreement between observed and predicted values of CE and FE. In conclusion, using such powerful models can enhance our ability to predict economic traits, make precise prediction of nutrition requirements, and achieve optimal performance in poultry production.

The protective effect of diabetes mellitus against prostate cancer: role of sex hormones

BACKGROUND

Diabetes mellitus (DM) has been associated with decreased risk of prostate cancer (PC) in several reports. Hormonal environment of diabetic patients is believed to be an important contributing factor in this regard.

METHODS

Using data from a multi-center case-control study in Iran, base line testosterone, sex hormone binding globulin (SHBG), estradiol, and albumin levels as well as thorough demographic and medical characteristics of 194 newly diagnosed prostate cancer patients were determined. There were 317 ethnicity-matched men with no cancer as controls as well. Data was analyzed for hormones of interest in DM patients regarding their cancer status.

RESULTS

Of 511 enrolled patients, twenty-one cases and 63 controls were diagnosed as DM. Patients with DM were significantly less likely to have PC (OR: 0.44, P = 0.003). Time since DM diagnosis was also inversely correlated with the risk of cancer (P trend < 0.0001). Control patients had significantly higher testosterone, estradiol, and testosterone/SHBG ratio (P < 0.05). As time since DM diagnosis increased by quartiles, testosterone significantly increased (P trend < 0.05). The risk of PC also significantly declined (P trend < 0.0001) following an initial remarkable increase early after DM diagnosis. After including the hormones in the logistic regression model, there was a weak, yet significant inverse association of testosterone/SHBG and DM duration with the risk of PC.

CONCLUSIONS

Based on our results DM duration is inversely correlated with the risk of prostate cancer. Our results do not support the hypothesis that sex hormones, including testosterone, play a major role in the protective effect of DM against PC.