Generalized Electrical Substitution Methods and Detectors for Absolute Optical Power Measurements.

We have developed generalized methods for electrical substitution optical measurements, as well as cryogenic detectors which can be used to implement them. The new methods detailed here enable measurement of arbitrary periodic waveforms by an electrical substitution radiometer (ESR), which means that spectral and dynamic optical power can be absolutely calibrated directly by a primary standard detector. Cryogenic ESRs are not often used directly by researchers for optical calibrations due to their slow response times and cumbersome operation. We describe two types of ESRs with fast response times, including newly developed cryogenic bolometers with carbon nanotube absorbers, which are manufacturable by standard microfabrication techniques. These detectors have response times near 10 ms, spectral coverage from the ultraviolet to far-infrared, and are ideal for use with generalized electrical substitution. In our first tests of the generalized electrical substitution method with FTS, we have achieved uncertainty in detector response of 0.13 % (k=1) and total measurement uncertainty of 1.1 % (k=1) in the mid-infrared for spectral detector responsivity calibrations. The generalized method and fast detectors greatly expand the range of optical power calibrations which can be made using a wideband primary standard detector, which can shorten calibration chains and improve uncertainties.

Development of electrical substitution Fourier transform spectrometry for absolute optical power measurements.

We have demonstrated the first continuous-scan electrical substitution Fourier transform spectrometer (ES-FTS), which serves initially as an apparatus for absolute spectral responsivity calibrations of detectors over the wavelength range from 1.5 µm to 11 µm. We present data on the realization of a spectral detector-comparator system with high accuracy, high dynamic range, high spectral resolution and fast measurement in the infrared region, which is tied directly to an absolute power scale through electrical substitution. The ES-FTS apparatus employs a commercial Fourier transform spectrometer and a custom electrical substitution bolometer detector to enable spectrally-resolved absolute optical power measurements. A generalization of electrical substitution techniques enables determination of the voltage waveform that must be applied to the bolometer's electrical heater to cancel the optical signal from a Michelson interferometer in order to quantify the time-dependent optical power incident on the bolometer. The noise floor of the electrical substitution bolometer is on the order of 10 pW/Hz½ and its response is expected to be linear from the noise floor to 1 mW. A direct comparison between a pyroelectric standard detector and the ES-FTS has been performed, and experimental results reported here show great potential for this technique.

Childhood trauma and cognitive functioning in individuals at clinical high risk (CHR) for psychosis.

Evidence suggests that early trauma may have a negative effect on cognitive functioning in individuals with psychosis, yet the relationship between childhood trauma and cognition among those at clinical high risk (CHR) for psychosis remains unexplored. Our sample consisted of 626 CHR children and 279 healthy controls who were recruited as part of the North American Prodrome Longitudinal Study 2. Childhood trauma up to the age of 16 (psychological, physical, and sexual abuse, emotional neglect, and bullying) was assessed by using the Childhood Trauma and Abuse Scale. Multiple domains of cognition were measured at baseline and at the time of psychosis conversion, using standardized assessments. In the CHR group, there was a trend for better performance in individuals who reported a history of multiple types of childhood trauma compared with those with no/one type of trauma (Cohen d = 0.16). A history of multiple trauma types was not associated with greater cognitive change in CHR converters over time. Our findings tentatively suggest there may be different mechanisms that lead to CHR states. Individuals who are at clinical high risk who have experienced multiple types of childhood trauma may have more typically developing premorbid cognitive functioning than those who reported minimal trauma do. Further research is needed to unravel the complexity of factors underlying the development of at-risk states.

The effect of selenium source on the oxidative status and performance of broilers reared at standard and high ambient temperatures.

1. This study investigated the oxidative status of broilers fed diets containing selenium (Se) from 14 to 35 d of age and reared at two different constant temperatures. Measurements of oxidative status included blood glutathione peroxidase (GSH-Px) and plasma total antioxidant status (TAS). Other variables included feed intake (FI), weight gain (WG), feed conversion ratio (FCR), Se levels in breast and liver tissue, jejunal villus morphometry, percentage weight of organs in relation to body weight; apparent metabolisable energy adjusted for nitrogen (AMEn); dry matter retention (DMR); fat retention (FR) and nitrogen retention (NR).2. The experiment started at 14 d of age, when 240 birds were randomly allocated to 48 pens (12 pens in four rooms). Treatments included a control diet 1 (SFC; 209.4 g/kg CP and 12.98 MJ/kg ME and no added Se containing saturated fat); diet 2 (SFSe) the control plus 12.605 mg/kg Se additive; diet 3 (USFC) was a second control diet (208.2 g/kg CP and 13.10 MJ/kg ME with no added Se containing unsaturated fat as rapeseed oil); diet 4 (USFSe) was the latter control plus 12.605 mg/kg Se additive. Two rooms were kept at a standard temperature of 20°C (ST) and two rooms were kept at high temperature of 35°C (HT).3. A temperature x Se interaction existed for GSH-Px in birds reared at ST (P < 0.05), and these birds had the highest levels of Se in liver tissue (P < 0.05). Fat x Se interactions were evident in breast tissue with highest levels in USFSe (P < 0.05). Adding Se improved jejunal VH: CD in USFSe fed birds (P < 0.001).4. Birds reared at ST had higher FI and WG than those reared at HT (P < 0.001), and had lower FCR than those reared at HT (P < 0.05). AMEn (MJ/kg DM) and FR were higher in birds fed USF diets, and lowest in birds fed SF (P < 0.50 and P < 0.001 respectively). NR was highest in birds raised at ST (P < 0.50).5. Broiler growth performance was reduced by HT. Oxidative status and Se in liver tissue was improved by adding Se in both diets.

Persistent negative symptoms in youth at clinical high risk for psychosis: A longitudinal study.

BACKGROUND: Severity of negative symptoms has been associated with poor functioning, cognitive deficits, and defeatist beliefs in schizophrenia patients. However, one area that remains understudied is persistent negative symptoms (PNS). Negative symptoms, including PNS, have been observed in those at clinical high-risk (CHR) for psychosis. The aim of this study was to determine if PNS were associated with functioning, neurocognition, and defeatist beliefs in a CHR sample. METHOD: CHR participants (n = 764) were recruited for the North American Prodrome Longitudinal Study. Negative symptoms were rated on the Scale of Psychosis-risk Symptoms. Generalized linear mixed models for repeated measures were used to examine changes over time between and within groups (PNS vs non-PNS). RESULTS: The PNS group (n = 67) had significant deficits in functioning at baseline, 6, 12, 18, and 24-months compared to the non-PNS group (n = 673). Functioning improved over time in the non-PNS group, while functioning in the PNS group remained relatively stable and poor over a two-year period. A consistent trend emerged demonstrating higher defeatist beliefs in the PNS group; however, this result was lost when controlling for persistent depressive symptoms. There were no significant differences between the groups on neurocognition, social cognition, and transition to psychosis. CONCLUSIONS: PNS exist in youth at CHR for psychosis, resulting in significant and persistent functional impairment, which remains when controlling for persistent depressive symptoms. PNS remain even in CHR youth who do not transition to psychosis. Thus, PNS may represent an unmet therapeutic need in CHR populations for which there are currently no effective treatments.

Impact of intra-operative hypotension on mortality rates and post-operative complications in dogs undergoing cholecystectomy.

OBJECTIVES: To report the mortality rate within a cohort of dogs undergoing cholecystectomy and investigate the impact of intra-operative hypotension on mortality. MATERIALS AND METHODS: Clinical records at five UK referral centres were reviewed for dogs undergoing cholecystectomy. Data collected included presenting signs, pre-operative blood test results, intra-operative data including frequency and duration of hypotension and the incidence and type of post-operative complications. RESULTS: Data from 119 dogs were included. Sixteen dogs (13%) died before discharge and by 28 days after surgery the total mortality was 19 dogs (17%). Hypotension lasting over 10 minutes during general anaesthesia occurred in 65 dogs (54.6%), with a mean ± sd duration of 36.1 ± 30.0 minutes. Intra-operative hypotension or the number of hypotensive episodes did not appear to be associated with in-hospital or 28-day mortality. American Society of Anaesthesiologists grade (of fitness for surgery) was significantly associated with both in-hospital and 28-day mortality on univariable analysis, as were post-operative hypoproteinaemia, ileus and pancreatitis. However on multivariable analysis, only ileus and pancreatitis were found to significantly impact mortality. CLINICAL SIGNIFICANCE: Dogs presenting with a higher American Society of Anaesthesiologists grade appear to have a higher risk of mortality, although intra-operative hypotension did not appear to be part of this risk.

The effect of feeding different sources and levels of selenium on growth performance and antioxidant status of broilers raised at two different temperatures.

1. This study examined the effects of different dietary sources and levels of selenium (Se) on growth performance, hepatic and breast meat Se content, glutathione peroxidase (GSH-Px) activity and total antioxidant status (TAS) in blood, when fed to broilers from 14 to 35 d of age and reared at two different temperatures (20°C and 35°C). 2. Five hundred and sixty male Ross 308 broilers were reared in a single floor pen and fed the same proprietary starter diet from 0 to 14 d age (229.9 g/kg CP and 12.67 MJ/kg ME, without Se supplementation). 3. The experiment started at 14 d age, and the birds randomly assigned to 112 raised-floor pens (0.36 m2 area, 5 birds/pen). Each of the seven experimental diets were offered to birds in 16 pens within four rooms. Two rooms were at 20°C and two rooms were maintained at 35°C. The experimental diets were fed from 14 to 35 d age and contained 214.9 g/kg CP and 13.11 MJ/kg ME. The experimental diets were as follows; control diet containing background Se only (0.189 mg/kg; C); low level sodium selenite (0.376 mg/kg; LSS): high level sodium selenite (0.558 mg/kg; HSS); low level commercial B Traxim® Se (0.244 mg/kg) (LBT); high level B Traxim® Se (0.448 mg/kg; HBT); low level selenised yeast (0.290 mg/kg; LSY); high level selenised yeast (0.487 mg/kg; HSY). 4. Birds consumed more when raised at 20°C compared to birds reared at 35°C (P ≤ 0.05). Birds fed lower Se level reared at 35°C had higher weight gain versus those fed higher Se level (P < 0.05). Birds fed SY had the lowest feed intake, weight gain and FCE (P < 0.05). The greatest GSH-Px activity was observed in birds fed SS diets (P < 0.001). There were interactions between diet x level for TAS, which were highest in birds fed LBT compared to birds fed HBT (P < 0.05). Breast Se content was higher in birds fed HSY compared to LSY (P < 0.001). The highest hepatic Se was seen in birds fed SY and lowest in C (P < 0.001). 5. Birds fed BT diets showed similar levels of Se to those birds fed inorganic Se, and similar levels of GSH-Px to birds fed SY. Further comparative work with broilers fed BT and other Se supplemented diets may elucidate the findings from this report.

Effect of age on the relationship between metabolizable energy and digestible energy for broiler chickens.

A total of 960 male Ross 308 chicks (day-old) were used to investigate the effect of age on the relationship between metabolizable energy (ME) and digestible energy (DE) for broiler chickens. Bird growth variables, nitrogen retention (NR), nitrogen digestibility (ND), as well as the relative weight of liver, pancreas, and the gastrointestinal tract were determined. Practical diets that compared 2 cereals (corn and wheat) and exogenous xylanase (0 or 16,000 BXU/kg) were evaluated at 5 ages (7, 14, 21, 28, and 35 D) in a 2 × 2 × 5 factorial arrangement of treatments with 8 replicates per treatment and started with 30 birds per replicate. A randomized block ANOVA analysis of repeated measures was performed, and a 2 × 2 × 5 factorial structure was used to investigate the 2 dietary treatment factors (cereal type and the presence of xylanase) within the 5 bird ages (7, 14, 21, 28, and 35 D), and their interactions. Apparent metabolizable energy (AME) increased linearly from 7 until 28 D of age, but (P < 0.05) decreased at 35 D of age. Digestible energy was high at 7 D of age, then dropped and remained similar (P > 0.05) from 14 to 35 D of age. The AME: DE ratio was lowest (P < 0.05) at 7 D of age but there were no (P > 0.05) differences thereafter. Cereal type and xylanase supplementation did not (P > 0.05) change the ME: DE ratio. The results indicate that determining ME before 14 D of age may give absolute values that are lower than would be obtained with older birds. ME values that are determined on older broiler chickens may overestimate the energy availability of practical feeds used in broiler starter feeds.

Long-term clinical outcomes following surgery for spontaneous pneumothorax caused by pulmonary blebs and bullae in dogs - a multicentre (AVSTS Research Cooperative) retrospective study.

OBJECTIVES: To report the clinical characteristics and recurrence rate of spontaneous pneumothorax secondary to pulmonary blebs and bullae following surgical management in a large cohort of dogs. To explore potential risk factors for recurrence and describe outcome. MATERIALS AND METHODS: Medical records were retrospectively reviewed for cases with spontaneous pneumothorax managed surgically between 2000 and 2017. Signalment, clinical presentation, diagnostic imaging, surgery, histopathology findings and patient outcomes were recorded. Follow-up was performed via patient records and telephone contact. RESULTS: Records of 120 dogs with surgically treated pneumothorax were identified and reviewed, with 99 cases appropriate for exploratory statistical analysis. Median follow-up was 850 days (range: 9-5105 days). Two- and 5-year survival rates were 88.4% and 83.5%, respectively. There was recurrence in 14 of 99 dogs (14.1%) with adequate follow-up, with a median time to recurrence of 25 days (1-1719 days). Univariable Cox regression analysis suggested increased risk for recurrence in giant breeds (hazard ratio = 11.05, 95% confidence interval: 2.82-43.35) and with increasing bodyweight (HR = 1.04, 95% confidence interval: 1.00-1.09). Of 14 dogs with recurrence, six were euthanased, two died of causes related to pneumothorax and six underwent further treatment, of which five were resolved. CLINICAL SIGNIFICANCE: Long-term survival for dogs with surgically managed spontaneous pneumothorax was good and associated with a low risk of recurrence. Giant breed dogs and increased bodyweight were the only variables identified as possible risk factors for recurrence. The outcome for dogs with recurrence undergoing a second intervention was also favourable.

Effect of feeding different sources of selenium on growth performance and antioxidant status of broilers.

1. This study was conducted to determine the effect of different sources of selenium (Se) on breast and liver tissue deposition, apparent metabolisable energy (AME), growth performance and antioxidant status of broilers, measured as Se content in liver and breast tissues and glutathione peroxidase (GSH-Px) in blood, when used in 0-35 d broiler chicken diets. 2. A total of 200 male Ross 308 broilers were used in the feeding trial, which comprised two dietary phases, a starter from 0 to 21 d and finisher from 21 to 35 d of age. Four treatments with 10 replications each were used. A control diet (C) was formulated that was sufficient in protein and energy (230 and 215 g/kg of crude protein and 12.67 and 13.11 MJ/kg of metabolisable energy, respectively), for both phases, but contained background Se only from the feed ingredients. Diet 2 (IS) was supplemented with 10.35 g/t inorganic, elemental source of Se. Diet 3 (SY) was supplemented with 136.36 g/t selenised yeast, an organic source derived from Saccharomyces cerevisiae. Diet 4 (SS) was supplemented with 0.666 g/t sodium selenite, an inorganic source. 3. Birds fed the SY diet consumed less and weighed less than those fed IS or C (P < 0.05; 0-35 d of age), but there was no difference compared to birds fed SS diets. There were no differences in FCR or dietary AME between broilers fed different Se sources. All diets containing supplementary Se increased concentrations in the liver and breast muscle, and for GSH-Px levels in blood compared to birds fed the C diet (P < 0.001). Birds fed SY diets had greater Se levels in liver and breast tissues compared to birds fed any of the other diets (P < 0.001). 4. Diets supplemented with Se had variable effects on broiler growth performances and antioxidant status. Feeding Se from a yeast source has higher transfer into breast tissues. Feeding different sources and levels of Se to birds in a more challenging situation to induce oxidative stress may bring more conclusive results.

Design and engineering colloidal magnetic particles for nanoscale thermometry.

Thermometry based on magnetic nanoparticles (MNPs) is an emerging technology that allows for remote temperature measurements throughout a volume that are impossible to achieve using conventional probe-based or optical methods. This metrology is based on the temperature-dependent nature of these particles' magnetization; however, commercially available MNPs generally display insufficient magneto-thermosensitivity for practical use in applications near room temperature. Here we present engineered MNPs based on cobalt-doped ferrites developed for 200 K - 400 K thermometry applications. The synthesis relies on easily scalable solution chemistry routes, and is tunable to afford MNPs of controlled size and composition. These improved nanothermometers form the basis of our effort to develop a practical means for spatially resolved, 3D, high-sensitivity measurements of temperature based on AC magnetometry.

Neurocognitive predictors of metacognition in individuals at clinical high risk for psychosis.

BACKGROUND: Metacognition refers to the ability to evaluate and control our cognitive processes. While studies have investigated metacognition in schizophrenia and clinical high risk for psychosis (CHR), less is known about the potential mechanisms which result in metacognitive deficits. AIMS: We aimed to investigate whether neurocognitive functions including attention, working memory, verbal learning and executive functions predicted the tendency to focus on one's thoughts (cognitive self-consciousness) and beliefs in the efficacy of one's cognitive skills (cognitive confidence). METHOD: Participants (130 CHR individuals) were recruited as part of the multi-site PREDICT study. They were assessed using the Metacognitions Questionnaire (MCQ) as well as measures of executive function (WCST), attention (N-Back), working memory (LNS) and verbal learning (AVLT). RESULTS: Cognitive competence was negatively correlated with N-Back while cognitive self-consciousness was positively correlated with N-Back and LNS. Linear regression analysis with N-Back, AVLT, LNS and WCST as predictors showed that neurocognition significantly predicted cognitive self-consciousness, with N-Back, LNS and WCST as significant predictors. The model accounted for 14% of the variance in cognitive self-consciousness. However, neurocognition did not result in a significant predictive model of cognitive competence. CONCLUSIONS: Neurocognition was associated with an increased focus on one's thoughts, but it was not associated with higher confidence in one's cognitive skills. Neurocognition accounted for less than one-sixth of the variance in metacognition, suggesting that interventions that target neurocognition are unlikely to improve metacognitive abilities.

Glucagon-like peptide 1 (GLP-1).

BACKGROUND: The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent ß-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW: In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS: Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.

Does hallucination perceptual modality impact psychosis risk?

OBJECTIVE: Subthreshold perceptual abnormalities are commonly used to identify individuals at clinical high risk (CHR) for developing a psychotic disorder. Predictive validity for modality-specific perceptual abnormality severity on psychosis risk is unknown. METHODS: We examined prospectively collected data from 164 individuals age 12-35 meeting criteria for CHR followed for 6-24 months or until conversion to psychosis. Using intake interview notes, baseline perceptual abnormality scores were split into auditory, visual, somatic/tactile, and olfactory/gustatory components, and auditory scores were further split into those for verbal vs non-verbal content. Relationships between perceptual abnormality characteristics and conversion were assessed with Cox proportional hazards regression and logistic regression. RESULTS: Unusual thought content and paranoia were predictive of conversion, but no modality-specific perceptual abnormality score predicted conversion status or days to conversion. However, when auditory perceptual abnormalities were further categorized as verbal vs non-verbal, the severity of verbal experiences was predictive of conversion to psychosis (P = 0.007). CONCLUSIONS: Perceptual abnormality scores failed to meaningfully predict conversion to psychosis in either direction in this CHR sample. However, verbal auditory experiences may identify a group of CHR individuals at elevated risk of conversion. Further exploration of the relationship between phenomenological aspects of perceptual abnormalities and conversion risk is warranted.

Nanokelvin DC and AC Meissner-transition-edge temperature detectors.

Based upon a superconducting transition edge sensor (TES), the Meissner-TES is a relatively new type of high resolution cryogenic thermometer which employs the magnetic transition of a superconductor to measure temperature. We have improved the signal-to-noise for DC sensing by a factor of 30 compared to our prior effort and developed a new AC mode which uses an oscillating magnetic field and a lock-in technique with much lower magnetic noise than the DC mode. The thermometer was tuned in situ over a range of operating temperatures 10-50 times larger than the transition width of the superconductor, using an applied persistent magnetic field. The DC mode can have sensitivity better than 1 nK for 100 s averaging, and the AC mode has sensitivity better than 120 nK for very small applied magnetic fields near 14 nT and 100 s averaging. The Meissner-TES can be applied to high resolution temperature control, high sensitivity infrared sensing, optical power scale realization, and the study of temperature-dependent phase transitions.

The Early Psychosis Screener for Internet (EPSI)-SR: Predicting 12 month psychotic conversion using machine learning.

INTRODUCTION: A faster and more accurate self-report screener for early psychosis is needed to promote early identification and intervention. METHODS: Self-report Likert-scale survey items were administered to individuals being screened with the Structured Interview for Psychosis-risk Syndromes (SIPS) and followed at eight early psychosis clinics. An a priori analytic plan included Spectral Clustering Analysis to reduce the item pool, followed by development of Support Vector Machine (SVM) classifiers. RESULTS: The cross-validated positive predictive value (PPV) of the EPSI at the default cut-off (76.5%) exceeded that of the clinician-administered SIPS (68.5%) at separating individuals who would not convert to psychosis within 12 months from those who either would convert within 12 months or who had already experienced a first episode psychosis (FEP). When used in tandem with the SIPS on clinical high risk participants, the EPSI increased the combined PPV to 86.6%. The SVM classified as FEP/converters only 1% of individuals in non-clinical and 4% of clinical low risk populations. Sensitivity of the EPSI, however, was 51% at the default cut-off. DISCUSSION: The EPSI identifies, comparably to the SIPS but in less time and with fewer resources, individuals who are either at very high risk to develop a psychotic disorder within 12 months or who are already psychotic. At its default cut-off, EPSI misses 49% of current or future psychotic cases. The cut-off can, however, be adjusted based on purpose. The EPSI is the first validated assessment to predict 12-month psychotic conversion. An online screening system, www.eps.telesage.org, is under development.

Longitudinal changes in social cognition in individuals at clinical high risk for psychosis: An outcome based analysis.

Social cognition deficits have been observed in individuals at clinical high risk (CHR) for psychosis. Longitudinal change in social cognition were analyzed in CHR individuals from the North American Prodrome Longitudinal Study (NAPLS2) based on outcome at 24 months. Individuals (n = 359) were classified into remission, symptomatic, prodromal progression and transition to psychosis (CHR-T) groups. Social cognition was assessed using theory of mind, emotion perception, and social perception tasks. There were no differences at baseline or 24 months between the groups on social cognition. Non-transition groups improved significantly over time on social cognition, but CHR-T did not show this effect.

Feeding dihydroquercetin to broiler chickens.

1. A total of 80 male Ross 308 broilers were used in a study to investigate the effect of dietary dihydroquercetin (DHQ) on growth performance variables, gastrointestinal tract (GIT) and immune organ development, glutathione peroxidase (GPx) and haemoglobin in blood, hepatic vitamin E content, dietary N-corrected metabolisable energy (AMEn) and nutrient retention coefficients when fed to broiler chickens from 7 to 35 d of age. 2. Two treatments were used in this study: control (C) and C + 0.5 g/kg extract of Siberian Larch (Larix sibirica) per kg feed, containing 85% DHQ. The diets were fed over 2 feeding phases, a grower phase from 7 to 28 d of age and a finisher phase from 28 to 35 d of age. The birds were reared under the breeder's recommended conditions. 3. In general, there were no effects of DHQ on growth performance of broiler chickens. However, the results of this experiment showed that there can be changes in the redness colour of the breast meat when DQH is fed. No negative effects of feeding DHQ at 0.5 g/kg diet were observed in this study. 4. Supplementation of poultry diets with DHQ under standard industry-rearing conditions did not improve the performance or any of the studied variables, except an increase of redness index of the breast fillets. Feeding DHQ at different doses and/or under more challenging conditions, e.g. heat stress, may, however, bring positive responses.