Skeletal muscle fitness and physiology as determinants of firefighter performance and safety: a narrative review.

Firefighters routinely perform tasks that are reliant on their muscular fitness, which includes muscular strength, power and endurance. Separately, firefighters can present with unique skeletal muscle physiology characteristics due to the strenuous nature of this occupation. This review aims to summarise muscular fitness and physiology as determinants of a firefighter's ability to perform occupation-specific tasks, identify the relevance of both muscular fitness and physiology to a firefighter's risk for sustaining a work-related injury, and address the contributions of muscular fitness and physiology on a firefighter's ability to recover from tasks and their readiness for performing subsequent or future tasks. The presented evidence reveals muscular fitness can determine a firefighter's capacity to perform their job effectively, while also influencing risk for occupational injury. Collectively, this review indicates exercise training emphasising improvements in muscular strength, power, and endurance (i.e. resistance training) should be encouraged in this occupation.

This review addressed muscular fitness and physiology in firefighters. Current evidence suggests firefighter task performance and risk for injury is associated with high levels of muscular fitness. Additionally, firefighters undergo unique changes in muscle morphology and physiology that can negatively affect the ability to safely perform occupation-specific tasks repeatedly.

Inconsistent discharge diagnoses for young cardiac arrest episodes: insights from a statewide registry.

BACKGROUND: Administrative coding of out-of-hospital cardiac arrest (OHCA) is heterogeneous, with the prevalence of noninformative diagnoses uncertain. AIM: To characterize the prevalence and type of non-informative diagnoses in a young cardiac arrest population. METHODS: Hospital discharge diagnoses provided to a statewide OHCA registry were characterised as either 'informative' or 'noninformative.' Informative diagnoses stated an OHCA had occurred or defined OHCA as occurring due to coronary artery disease, cardiomyopathy, channelopathy, definite noncardiac cause, or no known cause. Noninformative diagnoses were blank, stated presenting cardiac rhythm only, provided irrelevant information or presented a complication of the OHCA as the main diagnosis. Characteristics of patients receiving informative versus noninformative diagnoses were compared. RESULTS: Of 1479 patients with OHCA aged 1 to 50 years, 290 patients were admitted to 15 hospitals. Ninety diagnoses (31.0%) were noninformative (arrest rhythm = 50, blank = 21, complication = 10 and irrelevant = 9). Two hundred diagnoses (69.0%) were informative (cardiac arrest = 84, coronary artery disease = 54, noncardiac diagnosis = 48, cardiomyopathy = 8, arrhythmia disorder = 4 and unascertained = 2). Only 10 diagnoses (3.5%) included both OHCA and an underlying cause. Patients receiving a noninformative diagnosis were more likely to have survived OHCA or been referred for forensic assessment (P = 0.011) and had longer median length of stay (9 vs 5 days, P = 0.0019). CONCLUSION: Almost one third of diagnoses for young patients discharged after an OHCA included neither OHCA nor any underlying cause. Underestimating the burden of OHCA impacts ongoing patient and at-risk family care, data sampling strategies, international statistics and research funding.

Causes, circumstances, and potential preventability of cardiac arrest in the young: insights from a state-wide clinical and forensic registry.

AIMS: The causes, circumstances, and preventability of young sudden cardiac arrest remain uncertain. METHODS AND RESULTS: A prospective state-wide multi-source registry identified all out-of-hospital cardiac arrests (OHCAs) in 1-50 year olds in Victoria, Australia, from 2019 to 2021. Cases were adjudicated using hospital and forensic records, clinic assessments and interviews of survivors and family members. For confirmed cardiac causes of OHCA, circumstances and cardiac history were collected. National time-use data was used to contextualize circumstances. 1319 OHCAs were included. 725 (55.0%) cases had a cardiac aetiology of OHCA, with coronary disease (n = 314, 23.8%) the most common pathology. Drug toxicity (n = 226, 17.1%) was the most common non-cardiac cause of OHCA and the second-most common cause overall. OHCAs were most likely to occur in sleep (n = 233, 41.2%). However, when compared to the typical Australian day, OHCAs occurred disproportionately more commonly during exercise (9% of patients vs. 1.3% of typical day, P = 0.018) and less commonly while sedentary (39.6 vs. 54.6%, P = 0.047). 38.2% of patients had known standard modifiable cardiovascular risk factors. 77% of patients with a cardiac cause of OHCA had not reported cardiac symptoms nor been evaluated by a cardiologist prior to their OHCA. CONCLUSION: Approximately half of OHCAs in the young have a cardiac cause, with coronary disease and drug toxicity dominant aetiologies. OHCAs disproportionately occur during exercise. Of patients with cardiac cause of OHCA, almost two-thirds have no standard modifiable cardiovascular risk factors, and more than three-quarters had no prior warning symptoms or interaction with a cardiologist.

Nurse perspectives on the psychosocial care of patients with urinary incontinence in home hospice: A qualitative study.

BACKGROUND: Urinary incontinence is prevalent among patients receiving home hospice and presents multiple care management challenges for nurses and family caregivers. AIM: This study sought to understand how urinary incontinence influences the psychosocial care of patients receiving home hospice and the strategies that nurses employ to maximize patient and family comfort. DESIGN: Qualitative descriptive study using semi-structured interviews. SETTING/PARTICIPANTS: Nurses employed at a large not-for-profit hospice agency in New York City. RESULTS: Analyses of 32 interviews revealed three primary themes. First, nurses considered urinary incontinence to be associated with multiple psychosocial issues including embarrassment for patients and caregiver burden. Second, nurses described urinary incontinence as a threat to patient dignity and took steps to preserve their continence function. Third, nurses assisted patients and their families to cope with urinary incontinence through normalization, reframing incontinence as part of the disease process, mobilizing caregiving assistance, and encouraging use of continence supplies such as diapers and liners. CONCLUSION: Urinary incontinence influences the psychosocial care of patients receiving home hospice and nurses employ strategies to maximize patient and family comfort. Additional research is needed to examine the psychosocial benefits of facilitated discussions with patients and family members about incontinence, provision of caregiving support, and distribution of comprehensive incontinence supplies to patients with fewer resources.

Lithium therapy in patients on dialysis: A systematic review.

BACKGROUND: Lithium is a first-line pharmacotherapy for the treatment of bipolar disorder, but long-term use is associated with nephrotoxicity. However, as dialysis effectively eliminates lithium, it remains a pharmacotherapeutic option for patients on dialysis. This systematic review seeks to evaluate the dosing, safety, efficacy, and monitoring of lithium in patients receiving dialysis. METHOD: A PubMed database search performed May 5th, 2020, identified 535 article titles. After exclusion criteria were applied, a total of 15 articles were included in this systematic review. RESULTS: In 18 patients receiving dialysis, lithium was primarily used for the treatment of mood disorders. The majority of patients received 300-900 mg lithium carbonate thrice-weekly following dialysis, but several alternative lithium salts and dosing strategies were utilized. The pharmacokinetic properties of lithium in dialysis are not well understood and can be complicated by a serum lithium "rebound effect" following dialysis, due to a two-compartment volume of distribution. Additionally, presence of residual diuresis in some patients may be reason to administer lithium more frequently than thrice-weekly following dialysis. Lithium was shown to be an effective pharmacotherapy in all patients, with many demonstrating rapid improvement after drug initiation. Five patients experienced an adverse event on lithium, but only one patient required lithium discontinuation. CONCLUSION: Lithium may be used in patients on dialysis, with close monitoring of pre-dialysis serum lithium concentrations for at least two weeks after treatment initiation, followed by a lower frequency after stabilization to ensure therapeutic concentrations and reduce toxicity risk.

Higher rates but similar causes of young out-of-hospital cardiac arrest in rural Australian patients.

OBJECTIVE: To determine whether young rural Australians have higher rates or different underlying causes of out-of-hospital cardiac arrest (OHCA). DESIGN: A case-control design identified patients experiencing an OHCA, then compared annual OHCA rates and underlying causes in rural versus metropolitan Victoria. OHCA causes were defined as either cardiac or non-cardiac, with specific aetiologies including coronary disease, cardiomyopathy, unascertained cause of arrest, drug toxicity, respiratory event, neurological event and other cardiac and non-cardiac. For OHCAs with confirmed cardiac aetiology, cardiovascular risk profiles were compared. SETTING: A state-wide prospective OHCA registry (combining ambulance, hospital and forensic data) in the state of Victoria, Australia (population 6.5 million). PARTICIPANTS: Victorians aged 1-50 years old experienced an OHCA between April 2019 and April 2020. MAIN OUTCOME MEASURES: Rates and underlying causes of OHCA in young rural and metropolitan Victorians. RESULTS: Rates of young OHCA were higher in rural areas (OHCA 22.5 per 100 000 rural residents vs. 13.4 per 100 000 metropolitan residents, standardised incidence ratio 168 (95% CI 101-235); confirmed cardiac cause of arrest 12.1 per 100 000 rural residents versus 7.5 per 100 000 metropolitan residents, standardised incidence ratio 161 (95% CI 71-251). The underlying causation of the OHCA and cardiovascular risk factor burden did not differ between rural and metropolitan areas. CONCLUSION: Higher rates of OHCA occur in young rural patients, with standardised incidence ratio of 168 compared to young metropolitan residents. Rural status did not influence causes of cardiac arrest or known cardiovascular risk factor burden in young patients experiencing OHCA.

The End Unexplained Cardiac Death (EndUCD) Registry for Young Australian Sudden Cardiac Arrest.

In 2019, the first multi-source registry of sudden cardiac arrest and death for patients aged 1-50 years launched in Victoria, Australia. Sudden cardiac arrest (SCA) affects approximately fifteen hundred younger Victorians per year. The End Unexplained Cardiac Death (EndUCD) Registry enrols SCA/death (D) cases aged 1-50 years, providing family screening, access to psychological support through clinical sites and creating a genetic biorepository for whole-genome sequencing. The registry will support clear pathways of cardiac assessment, epidemiological profiling and routine family screening and psychological support.

Can post-mortem coronary artery calcium scores aid diagnosis in young sudden death?

This study sought to explore the feasibility and utility of post-mortem coronary artery calcium (CAC) scoring in identifying patients with ischemic heart disease as cause of sudden death. 100 deceased patients aged 18-50 years underwent post-mortem examination in the setting of sudden death. At post-mortem, fifty cases were determined to have ischemic heart disease, and fifty had death attributed to trauma or unascertained causes. The CAC score was calculated in a blinded manner from post-mortem CTs performed on all cases. CAC scores were assessable in 97 non-decomposed cases (feasibility 97%). The median CAC score was 88 Agatston units [IQR 0-286] in patients deceased from ischemic heart disease vs 0 [IQR 0-0] in patients deceased from other causes (p < 0.0001). Presence of any coronary calcification differed significantly between ischemic heart disease and non-ischemic groups (adjusted odds ratio 10.7, 95% CI 3.2-35.5). All cases with a CAC score > 100 (n = 22) had ischemic heart disease as the cause of death. Fifteen cases had a CAC score of zero but severe coronary disease at post-mortem examination. Post-mortem CAC scoring is highly feasible. An elevated CAC score in cases 18-50 years old with sudden death predicts ischemic heart disease at post-mortem examination. However, a CAC score of zero does not exclude significant coronary artery disease. Post-mortem CAC score may be considered as a further assessment tool to help predict likely cause of death when there is an objection to or unavailability of post-mortem examination.

Insights into sudden cardiac death: exploring the potential relevance of non-diagnostic autopsy findings.

AIMS: Unexplained sudden cardiac death (SCD) may be attributable to cardiogenetic disease. Presence or absence of autopsy anomalies detected following premature sudden death direct appropriate clinical evaluation of at-risk relatives towards inherited cardiomyopathies or primary arrhythmia syndromes, respectively. We investigated the relevance of non-diagnostic pathological abnormalities of indeterminate causality (uncertain) such as myocardial hypertrophy, fibrosis, or inflammatory infiltrates to SCD. METHODS AND RESULTS: At-risk relatives of unexplained SCD cases aged 1-64 years without prior cardiac disease (n = 98) with either normal and negative (40%, true sudden arrhythmic death syndrome; SADS) or isolated non-diagnostic (60%, uncertain sudden unexplained death; SUD) cardiac histological autopsy findings at a central forensic pathology unit were referred to the regional unexplained SCD clinic for clinical cardiac phenotyping. Uncertain SUD were older than true SADS cases (31.8 years vs. 21.1 years, P < 0.001). A cardiogenetic diagnosis was established in 24 families (24.5%) following investigation of 346 referred relatives. The proportions of uncertain SUD and true SADS explained by familial cardiogenetic diagnoses were similar (20% vs. 31%, P = 0.34, respectively), with primary arrhythmia syndromes predominating. Unexplained SCD cases were more likely than matched non-cardiac premature death controls to demonstrate at least one uncertain autopsy finding (P < 0.001). CONCLUSION: Primary arrhythmia syndromes predominate as familial cardiogenetic diagnoses amongst both uncertain SUD and true SADS cases. Non-diagnostic or uncertain histological findings associate with SUD, though cannot be attributed a causative status. At-risk relatives of uncertain SUD cases should be evaluated for phenotypic evidence of both ion channel disorders and cardiomyopathies.

A Prospective Study of Sudden Cardiac Death among Children and Young Adults.

BACKGROUND: Sudden cardiac death among children and young adults is a devastating event. We performed a prospective, population-based, clinical and genetic study of sudden cardiac death among children and young adults. METHODS: We prospectively collected clinical, demographic, and autopsy information on all cases of sudden cardiac death among children and young adults 1 to 35 years of age in Australia and New Zealand from 2010 through 2012. In cases that had no cause identified after a comprehensive autopsy that included toxicologic and histologic studies (unexplained sudden cardiac death), at least 59 cardiac genes were analyzed for a clinically relevant cardiac gene mutation. RESULTS: A total of 490 cases of sudden cardiac death were identified. The annual incidence was 1.3 cases per 100,000 persons 1 to 35 years of age; 72% of the cases involved boys or young men. Persons 31 to 35 years of age had the highest incidence of sudden cardiac death (3.2 cases per 100,000 persons per year), and persons 16 to 20 years of age had the highest incidence of unexplained sudden cardiac death (0.8 cases per 100,000 persons per year). The most common explained causes of sudden cardiac death were coronary artery disease (24% of cases) and inherited cardiomyopathies (16% of cases). Unexplained sudden cardiac death (40% of cases) was the predominant finding among persons in all age groups, except for those 31 to 35 years of age, for whom coronary artery disease was the most common finding. Younger age and death at night were independently associated with unexplained sudden cardiac death as compared with explained sudden cardiac death. A clinically relevant cardiac gene mutation was identified in 31 of 113 cases (27%) of unexplained sudden cardiac death in which genetic testing was performed. During follow-up, a clinical diagnosis of an inherited cardiovascular disease was identified in 13% of the families in which an unexplained sudden cardiac death occurred. CONCLUSIONS: The addition of genetic testing to autopsy investigation substantially increased the identification of a possible cause of sudden cardiac death among children and young adults. (Funded by the National Health and Medical Research Council of Australia and others.).

Determination of gastrointestinal passage rate using three different markers in laying hens.

The titanium dioxide (TiO2 ) marker technique is currently widely practiced as a method to evaluate gastrointestinal (GI) passage rate in poultry. However, this method requires sacrificing the animal to obtain digesta samples, is labour-intensive and eliminates the possibility of follow-up studies with the same individual. The aim of this study was to evaluate whether the radiographic methods barium-impregnated polyethylene spheres (BIPS) and barium sulphate (BaSO4 ) suspension are in agreement with the TiO2 technique and can be used as an alternative method for GI passage rate determination in laying hens. Whole-body radiographs were taken at different time points. Hens of group 3 (n = 55) were orally inoculated with 5 g of feed mixed with 0.15 g TiO2 , 5 hens per time point sacrificed, and whole gastrointestinal organs (crop, proventriculus, gizzard, small intestine and large intestine) were collected and analysed for TiO2 content. The average marker passage rate of hens administered BaSO4 was significantly faster than those administered BIPS (gizzard: 15.2 hr vs. 43.2 hr; small intestine: 15.2 hr vs. 38.4 hr, respectively). A greater percentage of BIPS remained in the crop at 0, 0.5, 2, 3 and 8 hr post-inoculation (p.i.) and in the gizzard at 2, 24, 36 and 48 hr p.i. (all p < 0.05) compared to TiO2 . In conclusion, the evaluation of the GI transit time is feasible using BIPS, TiO2 and BaSO4 . The evaluation of the GI transit time using BIPS and BaSO4 needs further investigation.

The Cardiac Genetics Clinic: a model for multidisciplinary genomic medicine.

OBJECTIVES: To describe patient characteristics, standard operating procedure, and uptake of genetic testing at the multidisciplinary Cardiac Genetics Clinic (CGC) at the Royal Melbourne Hospital during its first 6 years. DESIGN: Database exploration of referral diagnoses, sex, number of clinic visits and incidence of genetic testing in a population of individuals attending the CGC. SETTING: Tertiary referral hospital (Royal Melbourne Hospital) providing cardiac genetics services to the state of Victoria. PARTICIPANTS: All individuals initially attending the clinic between July 2007 and July 2013, either as the proband or as an at-risk family member. MAIN OUTCOME MEASURES: Classification of patients into diagnostic categories, number of probands and at-risk relatives assessed, incidence and outcomes of genetic testing. RESULTS: 1170 individuals were seen for the first time over the 6-year period; 57.5% made only one visit. The median age was 39 years. Most were encompassed within four broad diagnostic categories: cardiomyopathy (315 patients), aortopathy (303 patients), arrhythmia disorders (203 patients) and resuscitated cardiac arrest and/or family history of sudden cardiac death (341 patients); eight patients had "other" diagnoses. Genetic testing (mutation detection or predictive testing) was undertaken in 381 individuals (32.6%), and a pathogenic mutation was identified in 47.6% of tests, representing 15.3% of the total population. CONCLUSION: The CGC fulfils an important role in assisting clinicians and patients by reviewing genetic cardiac diagnoses. Clinical practice during the study period moved from a selected candidate gene approach to broader gene panel-based testing. This move to next-generation sequencing may increase the detection of mutations and variants of unknown significance. A major contribution by the clinic to the care of these individuals and their families is the provision (or negating) of a diagnosis, and of a plan for managing risks of predictable cardiac disease.

Sudden Cardiac Death in People With Schizophrenia: Higher Risk, Poorer Resuscitation Profiles, and Differing Pathologies.

BACKGROUND: People with schizophrenia account for approximately 1.0% of the population and seem to experience increased rates of sudden cardiac death (SCD). OBJECTIVES: This study sought to determine characteristics of increased SCD in people with schizophrenia. METHODS: The End Unexplained Cardiac Death (EndUCD) prospective state-wide registry compared people aged 15 to 50 years with and without schizophrenia who experienced SCD within a 2-year time period and were referred for forensic evaluation. RESULTS: We identified 579 individuals, of whom 65 (11.2%) had schizophrenia. Patients with schizophrenia were more commonly smokers (46.2% vs 23.0%; P < 0.0001), consumed excess alcohol (32.3% vs 21.4%; P = 0.05), and used QTc-prolonging medications (69.2% vs 17.9%; P < 0.0001). They were less likely to arrest while exercising (0.0% vs 6.4%; P = 0.04). Unfavorable arrest-related factors included lower rates of witnessed arrest (6.2% vs 23.5%; P < 0.0001), more likely to be found in asystole (92.3% vs 73.3%; P < 0.0001), and being more likely to be found as part of a welfare check after a prolonged period of time (median 42 hours vs 12 hours; P = 0.003). There was more frequent evidence of decomposition, and they more commonly underwent autopsy (41.2% vs 26.4%; P = 0.04 and 93.8% vs 82.5%; P = 0.05), with a diagnosis of nonischemic cardiomyopathy being more common (29.2% vs 18.1%; P = 0.04). CONCLUSIONS: People with schizophrenia account for 11% of young SCD patients referred for forensic investigations, exceeding population rates by 11-fold. They have a higher preexisting cardiac risk factor burden, unfavorable resuscitation profiles, and higher rates of nonischemic cardiomyopathy. Strategies targeting biopsychosocial support may deliver not only psychological benefits, but also help to decrease unwitnessed cardiac arrest.

Improving sorghum digestion in broilers by targeting fermentation of xylan.

This study was to examine if it is possible to accelerate sorghum digestion in broiler chickens by targeting fermentation of the xylan. Cobb 500 broilers (n = 960, 80 birds per treatment) were fed 12 sorghum-soybean meal-based dietary treatments fed as 3 phases (starter d 0 to 12, grower d 13 to 23, finisher d 24 to 35), with 8 replicate pens of 10 birds per treatment. For half of the treatments (n = 6), 10% of the sorghum in the diet was directly replaced with 10% wheat bran, as a source of fermentable fibre. The diets were supplemented with either 0, 50 or 2,000 mg/kg xylo-oligosaccharides (XOS), with or without xylanase application. Body weight gain (BWG), feed intake (FI) and feed conversion corrected for mortality (cFCR) was determined at d 0 to 35, and male and female body weight were measured on d 35. On d 35, ileum and caeca samples were collected from 2 birds per pen, for determination of caecal cellulase and xylanase activity, microbiota composition and short chain fatty acid (SCFA) concentration, and ileal XOS concentration. Supplementation with 2,000 mg/kg XOS caused increased BWG at d 0 to 35 (P = 0.007) and enhanced caecal propionic, valeric and succinic acid concentration (P < 0.05). Wheat bran increased FI (P = 0.018) and BWG (P = 0.016), as well as caecal Bifidobacteria concentration (P < 0.001). Ileal XOS concentration was greatest when feeding combined wheat bran, 2,000 mg/kg XOS, and xylanase, resulting in increased caecal total SCFA, acetic acid and butyric acid concentration, and xylanase and cellulase activity (P < 0.05). Results from this study present that feed efficiency in birds fed sorghum-based diets is improved as a consequence of supplementing with fermentable fibre, xylanase and XOS.

Non-starch polysaccharide-degrading enzymes may improve performance when included in wheat- but not maize-based diets fed to broiler chickens under subclinical necrotic enteritis challenge.

The present study investigated whether supplementing fibre-degrading enzymes can ameliorate the severity of subclinical necrotic enteritis (NE) in broiler chickens offered wheat- or maize-based diets. A total of 1,544 mixed-sex broiler chickens were assigned to 16 experimental treatments as a 2 × 2 × 4 factorial arrangement of treatments. The factors were the following: NE challenge, yes or no; diet type, wheat- or maize-based; and enzyme supplementation, control (no enzyme), family 10 xylanase (XYN10), family 11 xylanase (XYN11) or ß-mannanase (MAN). Each treatment was replicated 6 times, with 16 birds per replicate pen. A three-way challenge × diet type × enzyme interaction occurred for body weight at 21 d of age (P = 0.025) and overall feed conversion ratio (P = 0.001). In the non-challenged birds fed the wheat-based diet, supplementing MAN increased d 21 body weight compared to the control. In challenged birds fed the maize-based diet, supplemental XYN11 impeded body weight and overall FCR compared to the control. Birds offered the maize-based diet presented heavier relative gizzard weights at both 16 and 21 d of age (P < 0.001) and reduced liveability (P = 0.046) compared to those fed the wheat-based diet. Enzyme supplementation reduced ileal and jejunal digesta viscosity at 16 d of age only in birds fed the wheat-based diet (P < 0.001). XYN11 increased ileal digesta viscosity in birds fed the maize-based diet, and MAN reduced it in birds fed the wheat-based diet at 21 d of age (P = 0.030). Supplementing XYN11 improved ileal soluble non-starch polysaccharides (NSP) digestibility in birds fed the wheat-based diet compared to non-supplemented birds (P < 0.001). Birds fed the wheat-based diet displayed a higher abundance of Bifidobacterium, Lactobacillus and Enterobacteriaceae and butyric acid in the caeca at 16 d of age compared to birds fed the maize-based diet (P < 0.05). In conclusion, supplemental XYN11 exacerbated the negative impact of NE on growth performance in birds fed the maize-based diet. Supplementing wheat-based diets with fibre-degrading enzymes ameliorates production losses induced by NE.

The flow of non-starch polysaccharides along the gastrointestinal tract of broiler chickens fed either a wheat- or maize-based diet.

The present study characterised the types and amounts of non-starch polysaccharides (NSP) remaining undigested along the gastrointestinal tract (GIT) of broiler chickens offered a typical wheat- or maize-based diet. One-day old Cobb 500 mixed-sex chicks were assigned to 24 pens, with 10 birds/pen and 12 pens/treatment. Birds were offered the experimental diets in 3 phases (starter, day 0 to 10; grower, day 11 to 24 and finisher, day 25 to 35). Excreta and digesta samples from the crop, gizzard, duodenum, jejunum, ileum and caeca were collected at 12 and 35 days of age, and analysed for the NSP flow. The wheat-based diet contained higher levels of soluble NSP than the maize-based diet, whereas insoluble NSP levels were similar between the 2 diets. Detailed analysis of NSP constituents revealed that arabinoxylans were the primary NSP in the wheat-based diet, mostly in insoluble form. Pectins were the predominant NSP in the maize-based diet, followed by arabinoxylans. Overall, birds offered the wheat-based diet presented higher levels of soluble NSP remaining in all gut sections compared to birds offered the maize-based diet, at both 12 and 35 days of age (P < 0.050). Accumulation of insoluble NSP in the gizzard was noted in birds fed both diets, but was more pronounced in birds offered the maize-based diet compared to the wheat-based diet, at both 12 and 35 days of age (P < 0.001). The present study highlights marked differences in the amounts and types of NSP delivered to the different gut sections when feeding wheat-compared to maize-based diets, particularly in the gizzard and the lower GIT of birds.

Protease supplementation reduced the heat increment of feed and improved energy and nitrogen partitioning in broilers fed maize-based diets with supplemental phytase and xylanase.

An experiment was conducted to explore the effects of digestible amino acid (dAA) concentrations and supplemental protease on live performance and energy partitioning in broilers. Ross 308 male broilers (n = 288) were distributed into 24 floor pens and offered 1 of 4 dietary treatments with 6 replicates from 1 to 35 d of age. Dietary treatments consisted of a 2 × 2 factorial arrangement with dAA concentrations (standard and reduced [34 g/kg below standard]) and supplemental protease (without or with) as the main factors. At 1, 15, 28, and 35 d of age, feed and broilers were weighed to determine live performance. From 20 to 23 d of age, a total of 32 birds (2 birds/chamber, 4 replicates) were placed in closed-calorimeter chambers to determine respiratory exchange (heat production, HP), apparent metabolisable energy (AME), retained energy (RE), and net energy (NE). From 29 to 35 d of age, supplemental protease in the reduced-dAA diet decreased broiler feed conversion ratio (FCR) by 5.6 points, whereas protease supplementation in the standard-dAA diet increased FCR by 5.8 points. The indirect calorimetry assay revealed that supplemental protease decreased (P < 0.05) the heat increment of feed (HIF) by 0.22 MJ/kg. Also, from 20 to 23 d of age, broilers offered the reduced-dAA diet with supplemental protease had a higher daily body weight gain (BWG) (+10.4%), N intake (+7.1%), and N retention (+8.2%) than those offered the standard-dAA with supplemental protease. Broilers offered the reduced-dAA without supplemental protease exhibited a 3.6% higher AME-to-crude protein (CP) ratio than those offered other treatments. Protease supplementation in the standard- and reduced-dAA diets resulted in 2.7% and 5.6% lower AME intake-to-N retention ratios, respectively, compared with the unsupplemented controls. Reduced-dAA increased (P < 0.05) AME intake (+4.8%), RE (+9.8%), NE intake (+5.8%), NE intake-to-CP ratio (+3.0%), and RE fat-to-RE ratio (+8.6%). Protease supplementation increased (P < 0.05) respiratory quotient (+1.2%) and N retention-to-N intake ratio (+2.2%), NE-to-AME ratio (+1.9%), and reduced HP (-3.6%), heat increment (-7.4%), and NE intake-to-N retention (-2.5%). In conclusion, protease positively affected FCR and energy partitioning in broilers; responses were most apparent in diets with reduced-dAA concentrations.

Ileal profile of non-starch polysaccharides and oligosaccharides in response to exogenous enzymes in broiler chickens offered wheat- or maize-based diets under subclinical necrotic enteritis challenge.

The present study evaluated the impacts of fibre-degrading enzymes on the profiles of non-starch polysaccharides (NSP) and oligosaccharides (OS) in the ileum of broiler chickens offered wheat- or maize-based diets under subclinical necrotic enteritis (NE) challenge. A 2 × 2 × 4 factorial arrangement of treatments was used. Factors were the following: NE challenge, no or yes; diet type, wheat- or maize-based; and supplemental enzymes, control (no enzyme), family 10 xylanase (XYN10), family 11 xylanase (XYN11) or ß-mannanase (MAN). Birds in the challenged group were inoculated with Eimeria on d 9 and Clostridium perfringens on d 14 and 15. A 3-way interaction (P = 0.047) occurred on overall (d 0 to 16) weight gain. When NE was present, all the supplemental enzymes increased weight gain in birds fed the wheat-based diet; whereas in those fed the maize-based diet supplemental XYN10 and XYN11 decreased weight gain. When NE was absent, birds fed the wheat-based diet supplemented with XYN10 or MAN presented increased weight gain compared to non-supplemented birds, but no improvements with enzyme addition were observed in birds fed the maize-based diet. A 3-way interaction (P = 0.002) was observed on insoluble NSP level in the ileum. When NE was absent, all the supplemental enzymes reduced the ileal level of insoluble NSP, regardless of diet type. In the challenged birds, supplementing XYN10 and MAN reduced insoluble NSP level in the ileum, but only in birds fed the wheat-based diet. Ileal soluble NSP level was reduced by supplemental XYN11 and MAN, but only in birds fed the wheat-based diet, resulting in a 2-way diet type × enzyme interaction (P < 0.001). Ileal OS arabinose (P = 0.030) level was highest in birds offered the wheat-based diet supplemented with XYN11. Collectively, supplementation of NSP-degrading enzymes to the wheat-based diet enhanced bird performance regardless of NE challenge, with XYN11 significantly increasing oligosaccharide release. However, enzyme addition did not improve growth performance in birds fed maize-based diet, with supplemental XYN10 and XYN11 impeding weight gain when NE was present.

Artificial gut and the applications in poultry: A review.

Artificial gut models including both the gastric and intestinal phases have been used in poultry research for decades to predict the digestibility of nutrients, the efficacy of feed enzymes and additives, and caecal fermentation. However, the models used in the past are static and cannot be used to predict interactions between the feed, gut environment and microbiome. It is imperative that a standard artificial gut model for poultry is established, to enable these interactions to be examined without continual reliance on animals. To ensure the validity of an artificial model, it should be validated with in vivo studies. This review describes current practices in the use of artificial guts in research, their importance in poultry nutrition studies and highlights an opportunity to develop a dynamic gut model for poultry to reduce the number of in vivo experiments.

Dietary Soluble Non-Starch Polysaccharide Level Influences Performance, Nutrient Utilisation and Disappearance of Non-Starch Polysaccharides in Broiler Chickens.

This study evaluated the effect of dietary soluble non-starch polysaccharides (sNSP) on performance and nutrient utilisation in broilers from d 0 to 35. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed either wheat- or corn-soybean meal-based diets formulated to contain either a high, medium, or low sNSP content, in a 2 × 3 factorial arrangement, fed as Starter (d 0−14) and Grower (d 14−35). Birds fed the low sNSP level presented greater BWG at d 0−14 and lower feed intake at d 14−35 compared to birds fed the medium sNSP level (p < 0.005). At d 14, birds fed the high sNSP level presented greater ileal and total tract starch digestibility and total tract sNSP degradability and insoluble NSP degradability, compared to feeding the low sNSP level. At d 35, total tract DM and metabolisability of gross energy was greater in birds fed the medium sNSP level compared to those fed the high or low sNSP level (p < 0.005). Generally, bird performance and nutrient utilisation was greater in birds fed the corn-based diets compared to the wheat-based diets. These results illustrate that dietary sNSP level and composition influences bird performance and nutrient digestibility.