PACT - Prediction of amyloid cross-interaction by threading

Amyloid proteins are often associated with the onset of diseases, including Alzheimer's, Parkinson's and many others. However, there is a wide class of functional amyloids that are involved in physiological functions, e.g., formation of microbial biofilms or storage of hormones. Recent studies showed that an amyloid fibril could affect the aggregation of another protein, even from a different species. This may result in amplification or attenuation of the aggregation process. Insight into amyloid cross-interactions may be crucial for better understanding of amyloid diseases and the potential influence of microbial amyloids on human proteins. However, due to the demanding nature of the needed experiments, knowledge of such interactions is still limited. Here, we present PACT (Prediction of Amyloid Cross-interaction by Threading) - the computational method for the prediction of amyloid cross-interactions. The method is based on modeling of a heterogeneous fibril formed by two amyloidogenic peptides. The resulting structure is assessed by the structural statistical potential that approximates its plausibility and energetic stability. PACT was developed and first evaluated mostly on data collected in the AmyloGraph database of interacting amyloids and achieved high values of Area Under ROC (AUC=0.88) and F1 (0.82). Then, we applied our method to study the interactions of CsgA - a bacterial biofilm protein that was not used in our in-reference datasets, which is expressed in several bacterial species that inhabit the human intestines - with two human proteins. The study included alpha-synuclein, a human protein that is involved in Parkinson's disease, and human islet amyloid polypeptide (hIAPP), which is involved in type 2 diabetes. In both cases, PACT predicted the appearance of cross-interactions. Importantly, the method indicated specific regions of the proteins, which were shown to play a central role in both interactions. We experimentally confirmed the novel results of the indicated CsgA fragments interacting with hIAPP based on the kinetic characteristics obtained with the ThT assay. PACT opens the possibility of high-throughput studies of amyloid interactions. Importantly, it can work with fairly long protein fragments, and as a purely physicochemical approach, it relies very little on scarce training data. The tool is available as a web server at https://pact.e-science.pl/pact/ . The local version can be downloaded from https://github.com/KubaWojciechowski/PACT .

Machine Learning Prediction Model for Inflammatory Bowel Disease Based on Laboratory Markers. Working Model in a Discovery Cohort Study

Inflammatory bowel disease (IBD) is a chronic, incurable disease involving the gastrointestinal tract. It is characterized by complex, unclear pathogenesis, increased prevalence worldwide, and a wide spectrum of extraintestinal manifestations and comorbidities. Recognition of IBD remains challenging and delays in disease diagnosis still poses a significant clinical problem as it negatively impacts disease outcome. The main diagnostic tool in IBD continues to be invasive endoscopy. We aimed to create an IBD machine learning prediction model based on routinely performed blood, urine, and fecal tests. Based on historical patients’ data (702 medical records: 319 records from 180 patients with ulcerative colitis (UC) and 383 records from 192 patients with Crohn’s disease (CD)), and using a few simple machine learning classificators, we optimized necessary hyperparameters in order to get reliable few-features prediction models separately for CD and UC. Most robust classificators belonging to the random forest family obtained 97% and 91% mean average precision for CD and UC, respectively. For comparison, the commonly used one-parameter approach based on the C-reactive protein (CRP) level demonstrated only 81% and 61% average precision for CD and UC, respectively. Results of our study suggest that machine learning prediction models based on basic blood, urine, and fecal markers may with high accuracy support the diagnosis of IBD. However, the test requires validation in a prospective cohort.

Standardised Ileal Amino Acid Digestibility in Field Pea Seeds of Two Cultivars Differing in Flower Colour for Broiler Chickens: Effects of Bird Age and Microbial Protease

Simple Summary

The extent to which field peas can replace soybean meal in diets for broiler chickens is limited, and one of the reasons for this may be a lack of careful consideration given to the age-related amino acid availability differences in feed formulations. As the digestibility of amino acids in feeds for poultry is a sensitive gauge of their bioavailability, this study has determined and compared standardised ileal amino acid digestibility estimates for whole (raw) seeds of white- and coloured-flowered pea cultivars fed to young and older chickens (14 or 28 days old) in the presence or absence of exogenous protease in their diet. The results demonstrate that when a digestible amino acid system is used, the coefficients of essential amino acids determined at 14 days of age in low-tannin white-flowered peas are not applicable to the formulation of grower-type feed mixtures containing seeds of coloured-flowered cultivars. The increased digestibility of nutritionally essential amino acids in white-flowered pea fed to bids at both ages and in coloured-flowered pea fed to chickens aged 28 days can be expected from protease supplementation. These results contribute to improved use of peas as an alternative to soybean meal vegetable protein sources in diets for broiler chickens.

Abstract

This study aimed to determine and compare standardised ileal digestibility (SID) coefficients of amino acids (AA) in raw seeds of the white-(WF) and the coloured-flowered (CF) field pea cultivar as sole sources of AA in the diets fed to broiler chickens aged 14 or 28 days. An additional purpose was to check the influence of exogenous protease added to pea-based assay diets on AA SID in birds at both ages. Each assay diet was offered to six replicate pens. On both sampling days, the contents from the lower half of the ileum were collected for determination of the apparent digestibility values. The SID coefficients were calculated using ileal endogenous AA losses determined from birds fed an N-free diet. Results indicated a substantial advantage of WF pea over CF pea as a source of digestible Lys, Met, Cys, His, Ile, Leu, Phe, Val, Asp and Glu for 14-day-old chickens. With the exception of methionine and cysteine, there was no significant difference between these two cultivars in the SID values of AA in 28-day-old birds. The protease increased SID of nutritionally essential AA from WF pea-based diet at both ages, and from CF pea-based diet in chickens aged 28 days. In conclusion, the SID coefficients of indispensable AA determined at 14 days of age in low-tannin WF peas are not applicable to the formulation of grower-type feeds containing seeds of CF cultivars.

Biomarkers associated with poor prognosis in patients with end-stage heart failure

Background

Despite advances in the treatment, end-stage heart failure (HF) is a disease with a severe prognosis, showing an annual mortality rate of 30 to 50%. Due to a poor prognosis in this population of patients, it is necessary to accurately stratify the risk of death, including simple and effective prognostic markers.

Objective

This study aimed to determine biomarkers associated with mortality in patients with end-stage HF.

Material and methods

The study was a prospective analysis of optimally treated patients with end-stage HF, who were hospitalised at the Cardiology Department between 2016 and 2018. At the time of enrollment to the study routine laboratory tests, cardiopulmonary exercise tests, echocardiography and right heart catheterization were performed in all patients. Human Interleukin 33 (IL-33) and IL-1 Receptor Like 1 (IL1RL1) were measured by sandwich enzyme-linked immunosorbent assay (ELISA) with the commercially available kit (Human Il-33 and IL1RL1 ELISA kit, SunRedBio Technology Co, Ltd, Shanghai, China). Plasma concentration of N-terminal brain natriuretic peptide (NT-proBNP) was measured using a commercially available kit (Human NTproBNP ELISA kit, Roche Diagnostics, Mannheim, Germany). The endpoint was all-cause mortality during a one-year follow-up. The Medical University of Silesia's local Institutional Review Board approved the study protocol, and all patients provided informed consent.

Results

The final study group consisted of 282 patients (87.6% males, median age 57.0 years). One-year mortality rate in the analysed population was 28%. In a multivariate analysis, independent risk factors of death included NT-proBNP [Hazard Ratio (HR) 1.056 (95% Confidence Interval (CI): 1.024–1.089); P<0.001], sodium [HR 0.877 (95% CI: 0.815–0.944); p<0.001], IL33 [HR 0.977 (95% CI: 0.965- 0.989); p<0.001] and IL1RL1 [HR 1.015 (95% CI: 1.008–1.023); p<0.001) serum levels.

Conclusions

Our study showed that lower sodium and IL-33 levels, as well as higher NT-proBNP and IL1RL1 levels are associated with an increased risk of death in patients with end-stage HF during a one-year follow-up.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical University of SIlesia, Katowice, Poland

Factors associated with the cardiac allograft vasculopathy after heart transplantation

Introduction

Cardiac allograft vasculopathy (CAV) is a major threat to long-term survival after heart transplantation (HT). The frequency of CAV is estimated to be 8% at 1 year after HT, 30% at the 5-year follow-up, and as high as 50% within 10 years after the procedure. Therefore, it is necessary to select those factors that are closely associated with the presence of CAV and facilitate the proper, fast and minimally invasive diagnosis of this disease.

Purpose

The aim of this study was determine risk factors associated with CAV detection in patients after HT.

Material and methods

We analyzed 299 consecutive patients after HT who underwent routine visits in our institution between 2015 and 2017. During the visit, echocardiography, routine coronary angiography, laboratory tests and immunosuppressive drug serum concentrations were performed in all patients. In addition, 10 ml of peripheral blood was collected to determine human interleukin 33 (IL-33) and IL-1 Receptor Like 1 (IL1RL1). IL-33 and IL1RL1 concentrations were measured by sandwich enzyme-linked immunosorbent assay (ELISA) with the commercially available kit. The diagnosis of CAV was based on the results of coronary angiography and defined according to the current International Society for Heart and Lung Transplantation (ISHLT) criteria.The Medical University Local Institutional Review Board approved the study protocol, and all patients provided informed consent.

Results

Patients' median age was 59.00 (45.00–66.00) years, and 74.2% were men. The median time from HT to study inclusion was 9.03 (6.02–13.01) years. The frequency of CAV according to the ISHLT criteria in the analysed population was 47.5%. At the time of enrolment all patients were receiving immunosuppressive therapy with calcineurin inhibitor and mycophenolate mofetil, and were free from acute rejection (diagnosed either by echocardiography or biopsy), clinical signs of infection or symptoms of acute heart failure. Multivariate analysis using logistic regression confirmed that IL-33 OR 0.958 (0.944–0.972), p<0.0001 as well as IL1RL1 OR 1.061 (1.040–1.083), p<0.0001) serum concentrations, donor age OR 1.046 (1.009–1.085) p=0.015, left ventricular diastolic dimension OR 1.081 (1.016–1.149) p=0.015, and time from HT to blood collection OR 1.256 (1.151–1.371), p<0.0001 were independent factors of CAV detection.

Conclusions

Lower IL-33 and higher IL1RL1 serum concentrations, as well as donor age, left ventricular diastolic dimension and time from HT to blood collection are independently associated with CAV. This study provides non-invasive, low-cost, and simple indicators for CAV detection.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical University of Silesia, Katowice, Poland

Coronary sinus oxidative stress markers allow for accurate assessment of the prognosis in patients with advanced heart failure awaiting transplantation

Background

Oxidative stress is a cause of cardiac diseases and contribute to apoptosis, cardiac remodeling, cardiac growth and repair. The end-stage heart failure (HF) is associated with ischemia-reperfusion, increased neurohumoral activity, cytokine stimulation and presence of inflammatory cells. Above factors are stimuli which generate free radicals and can induce oxidative stress in the heart and cause damage to essential myocardial structures and function. However, the role of oxidative stress in end-stage HF has not been fully understood.

Purpose

This study aimed to evaluate the prognostic value of the oxidative stress markers in ambulatory patients with end-stage HF awaiting heart transplantation (HT) during a 1.5 year follow-up period.

Method

The study was a prospective analysis of 85 optimally treated adult patients with end-stage HF, who were added to the HT waiting list at the Cardiology Department between 2015 and 2016. At the time of enrollment to the study routine laboratory tests, cardiopulmonary exercise test, echocardiography, spirometry and right heart catheterization were performed in all patients. During right heart catheterization, 10 ml of coronary sinus blood was additionally collected to determine total oxidant status (TOS) and total antioxidant capacity (TAC) levels. TOS and TAC were measured by Erel's method. The endpoint was all-cause mortality during a 1.5 years follow-up. The Medical University of Silesia's local Institutional Review Board approved the study protocol, and all patients provided informed consent.

Results

Median age of the patients was 53.0 (43.0–56.0) years and 90.6% of them were male. During the observation period, the mortality rate was 40%. The area under the receiver operating characteristics (ROC) curves indicated an acceptable discriminatory power of TAC (AUC: 0.780 [CI: 0.677–0.883]; sensitivity 56%, and specificity 90%); and excellent power of TOS (AUC: 0.9530 [CI: 0.9279–0.9781]; sensitivity 88%, and specificity 94%) for 1.5 years mortality. Patients with a low TAC level (≤1.10) had a significantly worse 1.5-year survival compared to the group with a high TAC level (>1.10) (1.5 year survival: 20.8% versus 75.4%; (long rank p<0.001). Similarly, patients with a high TOS level (≥3.11) had a significantly worse survival compared to the group with a low TOS level (<3.11) (1.5- year survival: 9.1% versus 92.3%; p<0.001).

Conclusion

TAC with acceptable prognostic power and TOS with excellent prognostic power allows assessment of the prognosis in end-stage HF during a 1.5 year follow-up period.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical University of Silesia, Katowice, Poland

Copeptin, albumin and routine inflammatory markers are predictors of one-year mortality in patients with advanced heart failure underwent cardiac transplantation evaluation

Introduction

Despite significant advances in the prevention and treatment of heart failure (HF), the prognosis for patients with advanced stage of the disease is still poor. Therefore, a better understanding of the underlying HF pathophysiological mechanisms is crucial to improve prognosis in patients with advanced HF. One important research area is the role of inflammation in the pathophysiology of HF.

Purpose

This study aimed to investigate factors associated with mortality in HF patients with particular emphasis placed on inflammatory markers.

Methods

This is a prospective analysis of 282 optimally treated HF patients hospitalised in Cardiology Department between 2016 and 2018 for heart transplantation (HT) evaluation. Patients with contraindications to HT were excluded from the study. At the baseline echocardiography, routine laboratory tests, an ergospirometric exercise test, and right heart catheterisation were performed in all patients. In addition, 10 ml of peripheral blood was collected to determine inflammatory biomarkers. Human procalcitonin and copeptin concentrations were measured by the sandwich enzyme-linked immunosorbent assay (ELISA) with the commercially available kit. A highly sensitive latex-based immunoassay was used to detect plasma C-reactive protein (CRP) using the COBAS Integra 70 analyzer. The end-point of the study was all-cause mortality during one-year follow-up. The study protocol was approved by the Local Ethics Committee of our medical university. All patients provided informed, voluntary consent to participate in the study.

Results

The median age of patients was 57 (51–60) and 87.6% of them were male. A total of 79 (28%) patients died during a one-year follow-up. Multivariate analysis of the Cox proportional hazard model confirmed that procalcitonin [hazard ratio (HR) 1.003 (1.002–1.003), p<0.001], high sensitivity C-reactive protein (CRP) [HR 1.109 (1.039–1.183), p<0.002], copeptin [HR 1.109 (1.019–1.207), p<0.02] and albumin [HR 0.925 (0.873–0.979), p<0.01] serum concentrations, as well as Erythrocyte Sedimentation Rate (ESR) [HR 1.031 (1.001–1.063) p<0.05] were associated with mortality during a one-year follow-up.

Conclusions

Our study demonstrated that higher procalcitonin, CRP and copeptin serum concentrations as well as higher ESR and lower albumin serum concentrations are independently associated with reduced survival in patients with advanced HF.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical University of Silesia

Klotho protein, albumin level, left ventricular and left atrium dimensions are independently associated with moderate and severe cardiac allograft vasculopathy in heart transplant recipients

Background

Cardiac allograft vasculopathy (CAV) is one of the main risk factors influencing graft loss and patients survival. An important element of monitoring the patient after heart transplantation (HT) is the assessment of non-invasive indicators associated with the occurrence and progression of CAV. Therefore, new noninvasive sensitive and specific tools are necessary for detecting CAV early, which may result in the modification of immunosuppressive therapy, increase in statin doses, and intensive treatment of CAV-related comorbidities.

Purpose

The aim of the study was to research for factors associated with occurrence of moderate to severe CAV in heart transplant recipients.

Methods

Our analysis included consecutive adult patients after HT with CAV who underwent routine visits in our institution between 2015–2017. Exclusion criteria included history of kidney diseases, hepatitis B and C, autoimmune diseases, chronic pancreatitis or thyroid diseases, and cerebrovascular accidents. During each visit, all patients underwent echocardiography, laboratory tests, immunosuppressive drugs serum concentration analyses, and coronary angiographies. In addition, Klotho protein concentration was measured in all patients using sandwich enzyme-linked immunosorbent assay (ELISA) with the commercially available kit. Coronary angiographies of all patients enrolled to the study were reviewed by two independent interventional cardiologists to accurately classify coronary artery lesions according to International Society for Heart and Lung Transplantation (ISHLT) guidelines. Then, patients were divided into a group with mild CAV (1) and moderate to severe CAV (2/3). The local institutional review board of the Medical University of Silesia approved the study protocol, and all patients provided informed consent.

Results

The final group consisted of 141 patients with CAV. The age of the patients was 60.0 (53.0–66.0) and 77.5% of them were male. The median time from HT to include in the study was 11.6 (8.5–15.0) years. The frequency of CAV 2/3 in the analysed population was 36.6%. All included patients received optimal immunosuppressive therapy consisting of a calcineurin inhibitor (tacrolimus or cyclosporin) and mycophenolate mofetil. Multivariate analysis of logistic regression showed that Klotho protein (OR = 0.719 [0.598–0.866], p<0.001), albumin (OR=0.790 [0.686–0.910] p<0.001), left ventricular diastolic dimension (OR =1.135 [1.054–1.222], p<0.001), and left atrium dimension (OR=1.058 [1.013–1.106] p=0.012) were independent factors of CAV 2/3 presence.

Conclusions

Lower Klotho and albumin levels, as well as left ventricular and left atrium dimensions are the independent factors of moderate to severe CAV presence.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): MEdical University of Silesia, Katowice, Poland

Coronary sinus catalase and ceruloplasmin levels predict all-cause mortality in patients with end-stage heart failure awaiting heart transplantation

 

Background, As a consequence of the worldwide increase in life expectancy and due to significant progress in the pharmacological and interventional treatment of heart failure (HF), the proportion of patients that reach an advanced phase of disease is steadily growing. Hence, more and more numerous group of patients is qualified to the heart transplantation (HT), whereas the number of potential heart donors has remained invariable since years. It contributes to deepening in disproportion between the demand for organs which can possibly be transplanted and number of patients awaiting on the HT list. Therefore, accurate identification of patients who are most likely to benefit from HT is imperative due to an organ shortage and perioperative complications.

Purpose

The aim of this study was to identify the factors associated with reduced survival during a 1.5-year follow-up in patients with end-stage HF awating HT.

Method

We propectively analysed 85 adult patients with end-stage HF, who were accepted for HT at our institution between 2015 and 2016. During right heart catheterization, 10 ml of coronary sinus blood was additionally collected to determine the panel of oxidative stress markers. Oxidative-antioxidant balance markers included glutathione reductase (GR), glutathione peroxidase (GPx), glutathione transferase (GST), superoxide dismutase (SOD) and its mitochondrial isoenzyme (MnSOD) and cytoplasmic (Cu/ZnSOD), catalase (CAT), malondialdehyde (MDA), hydroperoxides lipid (LPH), lipofuscin (LPS), sulfhydryl groups (SH-), ceruloplasmin (CR). The study protocol was approved by the ethics committee of the Medical University of Silesia in Katowice. The endpoint of the study was mortality from any cause during a 1.5 years follow-up.

Results

The median age of the patients was 53.0 (43.0–56.0) years and 90.6% of them were male. All included patients were treated optimally in accordance with the guidelines of the European Society of Cardiology. Mortality rate during the follow-up period was 40%. Multivariate logistic regression analysis showed that ceruloplasmin (odds ratio [OR] = 0.745 [0.565–0.981], p=0.0363), catalase (OR = 0.950 [0.915–0.98], p=0.0076), as well as high creatinine levels (OR = 1.071 [1.002–1.144], p=0.0422) were risk factors for death during 1.5 year follow-up.

Conclusions

Coronary sinus lower ceruloplasmin and catalase levels, as well as higher creatinine level are independently associated with death during 1.5 year follow-up.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical University of SIlesia, Katowice, POland

Coronary sinus fetuin and sodium levels are independently associated with all-cause mortality in patients awaiting heart transplantation

Background

Risk stratification is a critical component of selection process of the patients with end-stage heart failure (HF) who are considered for heart transplantation (HT). Due to the constantly increasing number of the patients placed on the transplant waiting lists and a global shortage of organs available for HT, the key issue becomes an accurate risk stratification of death and proper organ allocation to these patients who will benefit the most from this form of treatment.

Purpose

The aim of this study was to identify the factors associated with mortality during a 1.5-year follow-up in patients with end-stage HF awaiting HT.

Methods

We prospectively analysed 72 patients with advanced HF awaiting HT at our institution between 2015 and 2016. At the time of inclusion in the study routine laboratory tests, cardiopulmonary exercise test, echocardiography, and right heart catheterisation were performed in all patients. During right heart catheterisation, 10 ml of coronary sinus blood was collected. Fetuin serum concentration was measured by the sandwich enzyme-linked immunosorbent assay (ELISA) with the commercially available kit.The end-point was defined as all-cause mortality during a 1.5 years follow-up. Our medical university local Institutional Review Board approved the study protocol, and all patients provided informed consent. The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments.

Results

Patients' median age was 53.00 (46.00–58.00) years, and 91.7% were men. During the 1.5-year follow-up, 31 (43.1%) patients died. The area under the receiver operating characteristic curve indicated a good discriminatory power of fetuin (AUC: 0.917 [95% CI: 0.858–0.977]). The cut-off point for fetuin (<632.36) had a sensitivity of 87% and a specificity of 83%. Patients with a lower fetuin level had a significantly worse 1.5-year survival compared to the group with a higher fetuin level (20.6% versus 89.5%; (long rank p<0.001). Fetuin OR 0.990 (0.986–0.996); p<0.001) and plasma sodium levels (OR, 0.640 [0.464–0.882]; p<0.001) were independent predictors of death during 1.5-year follow-up period.

Conclusions

Our study demonstrated that a low coronary sinus fetuin and peripheral blood sodium levels are associated with mortality patients with advanced HF accepted for HT. In addition, fetuin level, with excellent prognostic strength, allows for the risk stratification of death in analysed group of patients.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical University of Silesia

The Efficiency of Xylanase in Broiler Chickens Fed with Increasing Dietary Levels of Rye

In this paper, we present a study on the evaluation of the effect of xylanase addition to a diet with an increasing content of modern hybrid rye (Brasetto variety) on the performance indices and viscosity of small intestine content in broiler chickens. A total of 560 1-day-old male Ross 308 chickens were randomly assigned to 1 of 10 treatments, each comprising 7 replicate cages, with 8 male birds per cage. A 5 × 2 factorial arrangement was employed, with five dietary levels of ground rye (0%, 5%, 10%, 15%, and 20%). All the diets were either unsupplemented or supplemented with xylanase (200 mg/kg of feed; with minimum xylanase activity 1000 FXU/g). In the starter rearing period (1⁻21 days of age), the inclusion of rye (without xylanase supplementation) to the diet, even at the lowest dietary level (5%), negatively affected body weight gain (p < 0.05); there was no effect on feed intake and feed conversion ratio. In older chickens (the grower-finisher rearing period; 22⁻42 days of age), none of the dietary levels of rye (5⁻20%) affected growth performance indices. Similarly, no significant effect of increasing dietary level of rye was found for the entire rearing period (1⁻42 days of age). Diet supplementation with xylanase improved body weight gain and feed conversion ratio in chickens from 1 to 21 days of age. No positive effect of enzyme was found in older birds. No significant effects of the experimental factors used were noticed on the results of slaughter analysis, i.e., the carcass yield, breast meat yield, abdominal fat, and relative weight of the liver and gizzard. A high dietary concentration of rye (20%) increased the viscosity of small intestine content (p < 0.05); however, diet supplementation with xylanase significantly alleviated this effect. The findings of this experiment indicated that modern hybrid rye grain may be used at a 20% dietary level in broiler diets during the second feeding phase, i.e., from 22 to 42 days of age, without any detrimental influence on growth performance indices, while enzyme (xylanase) positively affected body weight gain and feed conversion ratio in younger chicks (1⁻21 days of age).

The Effects of Dietary Whey Lactose and Lactobacillus Agilis Bacteria on the Growth Performance, Physicochemical Conditions of the Digestive Tract and the Caecal Microbial Ecology of Broiler Chickens

The principal goal of this study was to assess the responses of broiler chickens raised on floor litter to the 2% dietary level of lactose (LAC) originating from dried whey fed in combination with live culture of Lactobacillus agilis bacteria (90 million cells/kg diet) in terms of the performance and basic postslaughter parameters, the lumen pH in some alimentary tract segments, concentration of volatile fatty acids (VFA ) in the total (T) and undissociated (UD) forms and count of selected microbial populations in the caeca determined by fluorescent in-situ hybridisation (FISH). A parallel aim was to evaluate the outcomes from the combined supplementation in comparison with feeding of LAC and the L. agilis bacteria as separate dietary supplements. Six hundred and forty Ross 308 chickens were placed in 16 floor pens (40 birds per pen having equal sex ratio) and were provided with free access to the feed (a mash maize-wheat-soybean meal-based diet) and water. Dietary treatments provided from day 8 to 42 of age were: LAC-free basal diet (CON), LAC-containing diet (CON + LAC), LAC-free diet with the addition of L. agilis (CON + BAC) and LAC-containing diet with addition of L. agilis (CON + LAC + BAC). The LAC supplementation caused significant decreases in the luminal pH of the crop, ileum and caeca, and the addition of the L. agilis bacteria reduced the pH in the crop and caeca. The overall concentration of total (T) volatile fatty acids was higher in the caeca of broilers receiving the LAC-containing diets. Both the LAC and the BAC supplements, independently from one another, resulted in significantly greater caecal levels of UD acetate, propionate and butyrate. The FISH analysis revealed that counts of Bacteroides sp./Prevotella sp. group were higher after the inclusion of LAC in the feed. All three dietary supplementations significantly reduced the total counts of the family Enterobacteriaceae and decreased the number of naturally occurring C. perfringens bacteria compared with the basal control diet (CON). Neither LAC inclusion nor BAC addition to the diet affected the counts of the Clostridium coccoides/Eubacterium rectale group. The synergistic effects of the simultaneous supplementation of LAC and L. agilis were found on the T butyrate concentration and on C. perfringens and the Enterobacteriaceae counts. No improvements in the body weight gains and post-slaughter traits were observed due to uncombined and combined supplementation with 2% LAC and L. agilis, indicating that the shifts in composition of the caecal microbiota toward a healthier composition by using these additives were not large enough to create the positive growth rate and processing yields responses in broilers maintained in a litter-floor environment.

Effect of selected feed additives on egg performance and eggshell quality in laying hens fed a diet with standard or decreased calcium content

The aim of the experiment with 240 ISA Brown hens fed the diets with standard or decreased Ca level was to evaluate the effect of selected feed additives on laying performance and eggshell quality. The hens were allocated to 10 treatments, each containing 12 cages (replicates) of 2 birds. A 2 × 5 experimental arrangement was used. From 26 to 70 wks of age, experimental diets containing 3.20 or 3.70% Ca were used. The diets were either not supplemented, or supplemented with sodium butyrate, probiotic bacteria, herb extracts blend or chitosan. The decreased dietary Ca reduced eggshell quality indices in older hens (43-69 wks) (P<0.05) without effect on performance indices. The addition of the probiotic, herb extracts, or chitosan increased the laying rate (P<0.05). In older hens, i.e. at 69 wk, chitosan increased eggshell thickness and breaking strength, while herb extracts increased eggshell thickness (P<0.05). There was no interaction between the experimental factors in performance and eggshell quality. The used feed additives had no influence on fatty acid profile of egg lipids, however diet supplementation with chitosan decreased cholesterol concentration in egg yolk lipids (P<0.05). It can be concluded that such feed additives as probiotic, herb extracts, or chitosan may positively affect performance and eggshell quality, irrespective of Ca dietary level.

Effects of Different Dietary Levels of Whey Lactose as a Prebiotic Disaccharide on the Productive Performances and Selected Indices of the Caecal Micro-Environment in Broiler Chickens

The primary aim of this study was to investigate the impact of three dietary levels of lactose (LAC) originating from conventional dried whey (DW) and the duration of these treatments (from 8 to 21 or to 42 days of age) on growth performance, basic post-slaughter traits and excreta quality of broiler chickens kept in cages. A secondary purpose was to investigate the effect of LAC level on some parameters of the caecal micro-environment and gross morphology in these birds. A total of 560 Ross 308 chickens (sex ratio 1:1) were assigned to 7 dietary combinations with 10 replicate cages of 8 birds per cage. The control group was fed basal diets consisting of maize, wheat and soybean meal. The other 6 groups received the same basal diets with DW added in amounts equivalent to a LAC dietary levels of 1, 2 or 3%. Only continuous feeding (day 8 to 42) with 1% and 2% levels of LAC was found to yield the overall body weight gain (BWG) during the whole 42-day rearing period, which was significantly higher than that on the control diet, with a larger share of breast meat in carcass at a 2% LAC. However, these effects were associated with greater faecal score values indicating more watery excreta compared with the control. Increasing levels of LAC augmented the relative caecal weight and length. A reduction in the caecal pH was confirmed at day 21 for birds fed 1% and 2% of dietary LAC. The lower pH values were correlated to an increased sum of total volatile fatty acids (VFA), causing large increases in the concentration of undissociated forms of individual VFA. The decline in plate counts of coliform bacteria was observed with 2% and 3% LAC, whereas the counts of lactic acid-producing bacteria (LAB) were higher at these two LAC levels. The present findings lead to the conclusion that the dietary level of 2% LAC originated from DW is the most effective in enhancing the productivity of broilers, with moderate occurrence of undesirable side effects.

Effects of conjugated linoleic acid on growth performance, feed conversion efficiency, and subsequent carcass quality in broiler chickens

The effect of dietary conjugated linoleic acid isomers (CLA) on growth performance, carcass composition, fatty acid composition of adipose and muscle tissues, and serum lipoproteins was investigated in broiler chickens. A total of 160 (eighty male and eighty female) chickens were allocated to four dietary treatments (0.0, 0.5, 1.0, and 1.5 % CLA) and fed a standard starter diet from 8 to 21 d, and a grower-finisher diet from 22–42 d. When determined for the total period 8–42 d, feed intake and body weight gains of broiler chickens were significantly reduced (from 3.31 to 3.12 kg and from 1615 to 1435 g respectively; P<0.05), particularly at the 1.5 % dietary CLA level. Feed conversion efficiency and carcass yield values showed no significant effects of dietary CLA. Abdominal fat deposition was significantly reduced (from 2.68 to 1.78 %; P<0.05), the relative proportion of breast muscles was unaffected, and that of leg muscles significantly increased (from 19.0 to 20.6 %; P<0.05). The concentration of CLA isomers (% of total methyl esters of fatty acids) increased linearly in tissue samples from broilers fed 0.5, 1.0, and 1.5 % dietary CLA. The relative proportions of saturated fatty acids (16:0, 18:0) were significantly (P<0.01) increased, and those of monounsaturated (16:1, 18:1) and polyunsaturated fatty acids (18:2, 20:4 in muscle tissues) significantly (P<0.05) reduced. Total serum cholesterol concentrations reached a maximum in broilers fed 1.0 % CLA and then decreased slightly (from 141.73 to 136.47 mg/dl; P<0.01). The same was true also for HDL-cholesterol (from 113.58 to 109.97 mg/dl; P<0.01). The HDL cholesterol:total cholesterol ratio and serum triacylglycerol concentration was unaffected. In conclusion, feeding CLA to broiler chickens resulted in substantial incorporation of CLA isomers into their tissue lipids, thus providing a potential CLA-rich source for human consumption.