Energetic costs of bill heat exchange demonstrate contributions to thermoregulation at high temperatures in toco toucans (Ramphastos toco).

Body temperature regulation under changes in ambient temperature involves adjustments in heat production and heat exchange rates between the animal and the environment. One mechanism involves the modulation of the surface temperature of specific areas of the body through vasomotor adjustment. In homeotherms, this thermoregulatory adjustment is essential for the maintenance of body temperature over a moderate temperature range, known as the thermal neutral zone (TNZ). The bill of the toco toucan (Ramphastos toco) has been described as a highly efficient thermal window and hypothesized to assist in the thermal homeostasis of this bird. Herein, we directly evaluated the contribution of heat exchange through the bill of the toco toucan and role of the bill in the delimitation of the TNZ. To do this, we measured metabolic rate (MR), via oxygen consumption, over a range of ambient temperatures from 0 to 35°C. MR measurements were made in birds with the bill intact and with the bill insulated. The limits of the TNZ did not differ between treatments, ranging from 10.8 to 25.0°C. The MR differed among treatments only at elevated temperatures (30 and 35°C), reaching 0.92±0.11 ml O2 g-1 h-1 (mean±s.d.) for the intact group and 1.13±0.13 ml O2 g-1 h-1 for the insulated group. These results indicate that although heat dissipation through the bill does not contribute significantly to widening of the TNZ, it may well be critically important in assisting body temperature regulation at higher temperatures extending above the upper limit of the TNZ.

Empirical estimation of skin resistance to water loss in amphibians: agar evaluation as a non-resistance model to evaporation.

Total resistance (rt) to evaporative water loss (EWL) in amphibians is given by the sum of the boundary layer (rb) and the skin resistance (rs). Thus, rs can be determined if the rb component is defined (rs=rt-rb). The use of agar models has become the standard technique to estimate rb under the assumption that the agar surface imposes no barrier to evaporation (rs=0). We evaluated this assumption by determining EWL rates and rb values from exposed surfaces of free water, a physiological solution mimicking the osmotic properties of a generalized amphibian, and agar gels prepared at various concentrations using either water or physiological solution as diluent. Water evaporation was affected by both the presence of solutes and agar concentration. Models prepared with agar at 5% concentration in water provided the most practical and appropriate proxy for the estimation of rb.

Cubic Octa-Carbon: Quantum-Chemical Design of Molecular Structure and Potential Way of Its Synthesis from Cubane.

Quantum-chemical calculation of most important parameters of molecular and electronic structures of octa-carbon C8 having cubic form (bond lengths, bond and torsion angles) using CCSD(T)/QZVP and DFT B3PW91/QZVP methods, has been carried out. NBO analysis data and HOMO/LUMO images for this compound are presented, too. Good agreement was found between the structural data obtained using the above two quantum-chemical methods and, also, with corresponding experimental data. Also, the standard thermodynamic parameters of formation of cubic C8 considered here, and namely standard enthalpy ΔfH0(298K), entropy Sf0(298K) and Gibbs' energy ΔfG0(298K) of formation for this compound were calculated. By using this data, a theoretically possible variant of the synthesis of this compound by dehydrogenation of cubane C8H8 is considered, and the thermodynamic characteristics of each of the four stages of this process have been calculated. It is noted that each of the four stages of this process is characterized by a very high (about 500 kJ/mol) enthalpy of activation, as a result of that, for their realization within a sufficiently short time, the use of appropriate catalysts is necessary.

Younger patients have worse outcomes after peripheral endovascular interventions for suprainguinal arterial occlusive disease.

OBJECTIVE: The choice of intervention for treating suprainguinal arterial disease, open bypass vs endovascular intervention, is often tempered by patient age and comorbidities. In the present study, we compared the association of patient age with 1-year major adverse limb events (MALE)-free survival and reintervention-free survival (RFS) rates among patients undergoing intervention for suprainguinal arterial disease. METHODS: The Vascular Quality Initiative datasets for bypass and peripheral endovascular intervention (PVI; aorta and iliac only) were queried from 2010 to 2017. The patients were divided into two age groups: <60 and ≥60 years at the procedure. Age-stratified propensity matching of patients in bypass and endovascular procedure groups by demographic characteristics, comorbidities, and disease severity was used to identify the analysis samples. The 1-year MALE-free survival and RFS rates were compared using the log-rank test and Kaplan-Meier plots. Proportional hazard Cox regression was used to perform propensity score-adjusted comparisons of MALE-free survival and RFS. RESULTS: A total of 14,301 cases from the Vascular Quality Initiative datasets were included in the present study. Propensity matching led to 3062 cases in the ≥60-year group (1021 bypass; 2041 PVI) and 2548 cases in the <60-year group (1697 bypass; 851 PVI). In the crude comparison of the matched samples, the older patients undergoing bypass had had significantly greater in-hospital (4.6% vs 0.9%; P < .001) and 1-year (10.5% vs 7.5%; P = .005) mortality compared with those who had undergone endovascular intervention. The rates of MALE (7.5% vs 14.3%; P < .001) and reintervention (6.7% vs 12.7%; P < .001) or death were significantly higher for the younger group undergoing PVI than bypass at 1 year. However, the rates of MALE (12.9% vs 14.3%; P = .298) and reintervention (12.7% vs 12.9%; P = .881) or death for were similar both procedures for the older group. Both log-rank analyses and the adjusted propensity score analyses of MALE-free survival and RFS in the two age groups confirmed these findings. The adjusted comparison of outcomes using propensity score matching favored PVI at 1-year survival (hazard ratio, 1.4; 95% confidence interval, 1.1-1.9; P = .003) for the older group but was not different for the younger group (hazard ratio, 0.6; 95% confidence interval, 0.3-1.0; P = .054). CONCLUSIONS: Among the patients aged <60 years undergoing intervention for suprainguinal arterial disease, the choice of therapy should be open surgical intervention given the higher risk of reintervention and MALE with endovascular intervention. Endovascular intervention should be favored for patients aged ≥60 years because of reduced perioperative mortality.

Heterotrophic flagellates and centrohelid heliozoans from marine waters of Curacao, the Netherlands Antilles.

Recent progress in understanding the early evolution of eukaryotes was tied to morphological identification of flagellates and heliozoans from natural samples, isolation of their culture and genomic and ultrastructural investigations. These protists are the smallest and least studied microbial eukaryotes but play an important role in the functioning of microbial food webs. Using light and electron microscopy, we have studied the diversity of heterotrophic flagellates and centrohelid heliozoans from marine waters of Curacao (The Netherlands Antilles), and provide micrographs and morphological descriptions of observed species. Among 86 flagellates and 3 centrohelids encountered in this survey, five heterotrophic flagellates and one сentrohelid heliozoan were not identified even to the genus. Some flagellate protists have a unique morphology, and may represent undescribed lineages of eukaryotes of high taxonomic rank. The vast majority (89%) of identified flagellates is characterized by wide geographical distribution and have been reported previously from all hemispheres and various climatic regions. More than half of the species were previously observed not only from marine, but also from freshwater habitats. The parameters of the species accumulation curve indicate that our species list obtained for the Curacao study sites is far from complete, and each new sample should yield new species.

Ammonia Storage in Hydrogen Bond-Rich Microporous Polymers.

The fascinating structural flexibility of porous polymers is highly attractive because it can result in optimized materials with specific host-guest interactions. Nevertheless, the fundamental mechanisms responsible for controlling the weak interactions of these hydrogen bond-rich networks-essential for developing smart task-specific materials used in recognition, capture, and sequestration processes-remain unexplored. Herein, by systematically comparing performance changes between poly(amic acid) (PAA)- and polycyclic imide (PI)-based porous polymers before and after NH3 adsorption, the role of hydrogen bonds in conformational lability and responsiveness toward guest molecules is highlighted. By combining thermal gravimetric analysis with neutron spectroscopy supported by DFT calculations, we demonstrate that PAA's chemical and physical stability is enhanced by the presence of stronger host-guest interactions. This observation also emphasizes the idea that efficient adsorption relies on having a high number of sites, upon which gas molecules can adsorb with greater affinity via strong hydrogen bonding interactions.

Feeding alters the preferred body temperature of Cururu toads, Rhinella diptycha (Anura, Bufonidae).

Ectothermic organisms depend primarily on external heat sources and behavioural adjustments to regulate body temperature. Under controlled conditions, in a thermal gradient, body temperature often clusters around a more or less defined range of preferred body temperatures (Tpref). However, Tpref may be modified in response to environmental parameters and/or physiological state. For example, meal ingestion is sometimes followed by a post-prandial thermophilic response leading to a transient increment in Tpref. Although thought to optimize digestive processes, its occurrence, magnitude, and possible determinants remains scarcely documented for anuran amphibians. Herein, we investigated whether the Cururu toad, Rhinella diptycha, exhibits a post-prandial thermophilic response by monitoring the body temperature of fasting and fed toads while they were maintained in a thermal gradient. We found that the toads' Tpref increased by about 13% from day 2 to 4 after feeding, in comparison with the Tpref recorded under fasting. Also, fed animals exhibited a broader range for Tpref at days 2 and 3 post-prandial, which reflects a greater level of locomotor activity compared to fasting individuals. We conclude that R. diptycha is capable to exhibit a post-prandial thermophilic response under the controlled conditions of a thermal gradient. Although this thermoregulatory adjustment is thought to optimize meal digestion yielding important energetic and ecological benefits, its occurrence in anuran amphibians in nature remains uncertain.

Effects of temperature and meal size on the postprandial metabolic response of Leptodactylus latrans (Anura, Leptodactylidae).

The postprandial increment of metabolism, often referred to as specific dynamic action (SDA), encompasses the summed costs of meal ingestion, digestion, absorption, and assimilation. Different SDA parameters, such as its magnitude, duration, and relative cost, are affected by a diverse set of environmental and physiological determinants, including meal size and body temperature. While the influence of these variables has been thoroughly examined in most ectothermic vertebrate groups, few studies have focused on the determinants and consequences of the SDA response in anuran amphibians. Thus, we examined the effects of meal size and body temperature on the SDA response of a Neotropical frog, Leptodactylus latrans, by measuring the rates of oxygen consumption of frogs while fasting and after being fed meals of different sizes at different temperatures. SDA lasted from 3 to 5 days and increased with meal size for frogs fed meals equivalent to 5-15% of their body mass. SDA cost was not affected by meal size and averaged 14.6% of the caloric content of the meal. Temperature increment was accompanied by proportional increases in metabolic rate and shorter SDA duration. The relative SDA cost averaged 14.8% of the meal caloric content at 20°C and 25°C, but increased to 23.5% at 30°C. Our results indicate that meal size imposes no physiological or energetic constraint to L. latrans feeding. Digestion at temperatures near the thermal preference of the species seems to optimize energetic return, whereas the shortening of SDA duration at higher temperatures may provide significant ecological advantages.

Exposure to fluctuating temperatures leads to reduced immunity and to stress response in rattlesnakes.

Ectothermic organisms often experience considerable variation in their body temperature throughout the circadian cycle. However, studies focusing on the measurement of physiological traits are usually performed under constant temperature regimes. This mismatch between thermal exposure in the field and experimental conditions could act as a stressor agent, as physiological functions are strongly influenced by temperature. Herein, we asked the question whether constant thermal regimes would cause a stress response and impact the immunity of the South American rattlesnake (Crotalus durissus) when compared with a fluctuating thermal regime. We addressed this question by determining heterophil:lymphocyte (H:L) ratio, plasma bacteria-killing ability (BKA) and corticosterone (CORT) levels in snakes kept under a constant temperature regime at 30°C, and under a fluctuating regime that oscillated between 25°C at night and 35°C during the day. The experiments had a mirrored design, in which half of the snakes were subjected to a fluctuating-to-constant treatment, while the other half was exposed to a constant-to-fluctuating treatment. The shift from constant to fluctuating thermal regime was accompanied by an increase in plasma CORT levels, indicating the activation of a stress response. Exposure to a fluctuating thermal regime at the onset of the experiments induced a decrease in the BKA of rattlesnakes. H:L ratio was not affected by treatments and, therefore, the shift between thermal regimes seems to have acted as a low-intensity stressor. Our results suggest that removal from temperatures close to the snake's preferred body temperature triggers a stress response in rattlesnakes.

Biophysical Modeling of Water Economy Can Explain Geographic Gradient of Body Size in Anurans.

Geographical gradients of body size express climate-driven constraints on animals, but whether they exist and what causes them in ectotherms remains contentious. For amphibians, the water conservation hypothesis posits that larger bodies reduce evaporative water loss (EWL) along dehydrating gradients. To address this hypothesis mechanistically, we build on well-established biophysical equations of water exchange in anurans to propose a state-transition model that predicts an increase of either body size or resistance to EWL as alternative specialization along dehydrating gradients. The model predicts that species whose water economy is more sensitive to variation in body size than to variation in resistance to EWL should increase in size in response to increasing potential evapotranspiration (PET). To evaluate the model predictions, we combine physiological measurements of resistance to EWL with geographic data of body size for four different anuran species. Only one species, Dendropsophus minutus, was predicted to exhibit a positive body size-PET relationship. Results were as predicted for all cases, with one species-Boana faber-showing a negative relationship. Based on an empirically verified mathematical model, we show that clines of body size among anurans depend on the current values of those traits and emerge as an advantage for water conservation. Our model offers a mechanistic and compelling explanation for the cause and variation of gradients of body size in anurans.

Droplet bubbling evaporatively cools a blowfly.

Terrestrial animals often use evaporative cooling to lower body temperature. Evaporation can occur from humid body surfaces or from fluids interfaced to the environment through a number of different mechanisms, such as sweating or panting. In Diptera, some flies move tidally a droplet of fluid out and then back in the buccopharyngeal cavity for a repeated number of cycles before eventually ingesting it. This is referred to as the bubbling behaviour. The droplet fluid consists of a mix of liquids from the ingested food, enzymes from the salivary glands, and antimicrobials, associated to the crop organ system, with evidence pointing to a role in liquid meal dehydration. Herein, we demonstrate that the bubbling behaviour also serves as an effective thermoregulatory mechanism to lower body temperature by means of evaporative cooling. In the blowfly, Chrysomya megacephala, infrared imaging revealed that as the droplet is extruded, evaporation lowers the fluid´s temperature, which, upon its re-ingestion, lowers the blowfly's body temperature. This effect is most prominent at the cephalic region, less in the thorax, and then in the abdomen. Bubbling frequency increases with ambient temperature, while its cooling efficiency decreases at high air humidities. Heat transfer calculations show that droplet cooling depends on a special heat-exchange dynamic, which result in the exponential activation of the cooling effect.

The consequences of seasonal fasting during the dormancy of tegu lizards (Salvator merianae) on their postprandial metabolic response.

Tegu lizards (Salvator merianae) aestivate for up to 5 months during Brazil's winter, when they retreat to burrows and halt most activities. Dormant tegus reduce their gastrointestinal (GI) mass, which allows a substantial energy economy. This strategy, however, implies that the first post-dormancy digestion would be more costly than subsequent feeding episodes as a result of GI atrophy. To address this, we determined the postprandial metabolic response (SDA) of the first (M1), second (M2) and several (RM) feeding episodes after tegus' dormancy. Another group of tegus (PF) was subjected to an extra 50 day fasting period after arousal. Glucose, triglycerides and uric acid levels were checked before and after feeding. M1 digestion lasted twice as long and cost twofold more when compared with M2 or RM, in agreement with the idea that GI atrophy inflates digestion cost at the first post-dormancy meal. The SDA response was similar in M2 and RM, suggesting that the GI tract was fully reorganized after the first feeding. The SDA cost was equal in PF and RM, implying that the change in state per se (dormant to arousal) triggers the regrowth of GI, independently of feeding. Fasting tegus at M1 presented higher triglyceride and lower uric acid levels than fed tegus, indicating that fasting is mainly sustained by fat storage. Our results show that seasonal fasting imposes an extra digestion cost to tegus following their next feeding, which is fully paid during their first digestion. This surplus cost, however, is negligible compared with the overall energetic savings from GI tract atrophy during the dormancy period.

The association of Carotid Revascularization Endarterectomy versus Stent Trial (CREST) and Centers for Medicare and Medicaid Services Carotid Guideline Publication on utilization and outcomes of carotid stenting among "high-risk" patients.

OBJECTIVE: Since the 2004 approval by the United States Food and Drug Administration of carotid artery stenting (CAS), there have been two seminal publications about CAS reimbursement (Centers for Medicare and Medicaid Services guidelines; 2008) and clinical outcomes (Carotid Revascularization Endarterectomy versus Stent Trial [CREST]; 2010). We explored the association between these publications and national trends in CAS use among high-risk symptomatic patients. METHODS: The most recent congruent data sets of the Nationwide Inpatient Sample (NIS) were queried for patients undergoing carotid revascularization. The sample was limited to include only patients who were defined as "high-risk" if they had a Charlson Comorbidity Score of ≥3.0. Subgroup analyses were performed of high-risk patients with symptomatic carotid stenosis. Utilization proportions of CAS were calculated quarterly from 2005 to 2011 for NIS. Three time intervals related to Centers for Medicare and Medicaid Services guidelines and CREST publication were selected: 2005 to 2008, 2008 to 2010, and after 2010. Logistic regression with piecewise linear trend for time was used to estimate different trends in CAS use for the overall high-risk sample and for neurologically asymptomatic and symptomatic cases. Multivariate logistic regression was used to compare odds of postoperative mortality and stroke between these two procedures at different time intervals independent of confounding variables. RESULTS: During the study period, 20,079 carotid endarterectomies (CEAs) and 3447 CAS procedures were performed in high-risk patients in the NIS database. CAS utilization constituted 20.5% of carotid revascularization procedures among high-risk symptomatic patients, with a significant increase from 18.6% to 24.4% during the study period (P < .001). There was an initial increase during 2005 to 2008 in the rate of CAS compared with CEA, CAS utilization significantly decreased during 2008 to 2010 by a 3.3% decline in the odds ratio (OR) of CAS per quarter (OR, 0.967; 95% confidence interval [CI], 0.943-0.993; P = .002), and after CREST (after 2010), CAS utilization continued to increase significantly from the prepublication to the postpublication time interval. The odds of in-hospital mortality (OR, 2.56; 95% CI, 1.17-5.62; P = .019) and postoperative in-hospital stroke (OR, 1.53; 95% CI, 1.09-3.68; P = .024) were independently and significantly higher for CAS patients in the overall sample. CONCLUSIONS: The use of CAS for carotid revascularization in a high-risk cohort of patients has significantly increased from 2005 to 2011. Compared with CEA, CAS independently increased the odds of perioperative in-hospital stroke in all high-risk patients and of in-hospital mortality in symptomatic high-risk patients.

Differences in Infant Care Practices and Smoking among Hispanic Mothers Living in the United States.

OBJECTIVE: To assess the association between maternal birth country and adherence to the American Academy of Pediatrics safe sleep recommendations in a national sample of Hispanic mothers, given that data assessing the heterogeneity of infant care practices among Hispanics are lacking. STUDY DESIGN: We used a stratified, 2-stage, clustered design to obtain a nationally representative sample of mothers from 32 US intrapartum hospitals. A total of 907 completed follow-up surveys (administered 2-6 months postpartum) were received from mothers who self-identified as Hispanic/Latina, forming our sample, which we divided into 4 subpopulations by birth country (US, Mexico, Central/South America, and Caribbean). Prevalence estimates and aORs were determined for infant sleep position, location, breastfeeding, and maternal smoking. RESULTS: When compared with US-born mothers, we found that mothers born in the Caribbean (aOR 4.56) and Central/South America (aOR 2.68) were significantly more likely to room share without bed sharing. Caribbean-born mothers were significantly less likely to place infants to sleep supine (aOR 0.41). Mothers born in Mexico (aOR 1.67) and Central/South America (aOR 2.57) were significantly more likely to exclusively breastfeed; Caribbean-born mothers (aOR 0.13) were significantly less likely to do so. Foreign-born mothers were significantly less likely to smoke before and during pregnancy. CONCLUSIONS: Among US Hispanics, adherence to American Academy of Pediatrics safe sleep recommendations varies widely by maternal birth country. These data illustrate the importance of examining behavioral heterogeneity among ethnic groups and have potential relevance for developing targeted interventions for safe infant sleep.

Postdischarge Feeding Interactions and Neurodevelopmental Outcome at 1-Year Corrected Gestational Age.

OBJECTIVE: To determine the extent to which postdischarge feeding behaviors and interactions among caregiver-preterm infant dyads are associated with infant neurodevelopment at 1-year corrected gestational age (CGA). STUDY DESIGN: We studied 119 preterm infants born <34 weeks gestation and <1750 g at birth, and their caregivers, enrolled in the Collaborative Home Infant Monitoring Evaluation with in-person feeding assessments according to the Nursing Child Assessment Feeding Scale (NCAFS) at 39-59 weeks postmenstrual age that completed Bayley Scales of Infant Development, Second Edition testing at 1 year CGA. RESULTS: Mean ± SD gestational age was 29.6 ± 2.4 weeks, and birth weight was 1260 ± 320 g. After adjustment for maternal and infant demographics, gestational age at birth, discharge and birth weight, mode of infant feeding, and caregiver type during the postdischarge NCAFS assessment, overall NCAFS scores were positively associated with higher 1-year CGA Bayley mental developmental index (MDI) scores (for each 1 SD increase in overall NCAFS score, MDI increased by 2.8 [95% CI 0.7, 4.9] points). Among individual NCAFS domains, strongest effects were seen for caregiver responsiveness to infant distress, such that, compared with dyads having domain scores of 11 (highest possible score), the adjusted mean difference in MDI was 8.3 points (95% CI -15.2, -1.4) lower among dyads with scores <9. CONCLUSIONS: Caregiver-preterm infant feeding interaction and caregiver responsiveness to preterm infant feeding distress were associated with preterm infant Bayley MDI at 1-year CGA. Caregiver-infant feeding interaction may represent a modifiable factor to improve the neurodevelopment of at-risk preterm infants.

The evolution of the meatal chamber in crocodyliforms.

The unique outer ear of crocodylians consists of a large meatal chamber (MC) concealed by a pair of muscular earlids that shape a large part of the animal's head. This chamber is limited medially by the enlarged tympanic membrane. Yet, the anatomy of this distinctive and complex region is underexplored and its evolutionary history untraced. The osteology and soft tissues of the MC in extant crocodylians was analysed to describe it and establish osteological correlates within this region. A broad survey of the osteological correlates was conducted in major clades of fossil crocodyliforms to estimate evolutionary trends of the MC. The reorganization of the MC at the origin of crocodyliforms includes characters also present in more basal taxa such as 'sphenosuchians' as well as unique traits of crocodyliforms. Three major patterns are recognized in the MC of basal mesoeucrocodylians. The distinct 'thalattosuchian pattern' indicates that extensive modifications occurred in this clade of aquatic fossil crocodyliforms, even when multiple alternative phylogenetic positions are taken into account. Some traits already established in putative closely related clades are absent or modified in this group. The 'basal notosuchian/sebecian pattern' is widespread among basal metasuchians, and establishes for the first time characters maintained later in neosuchians and extant forms. The 'advanced notosuchian pattern' includes modifications of the MC possibly related to a terrestrial lifestyle and potentially a structure analogous to the mammalian pinna. The main variation in the MC of neosuchians is associated with the homoplastic secondary opening of the cranioquadrate passage. The inferred phylogenetic trends in the crocodyliform MC suggest the great anatomical disparity in this region followed a complex evolutionary pattern, and tympanic hearing played an important role in the origin and diversification of Crocodyliformes.

Seasonal reproductive endothermy in tegu lizards.

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as "true endotherms": the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy.

Physiological responses of Brazilian amphibians to an enzootic infection of the chytrid fungus Batrachochytrium dendrobatidis.

Pathophysiological effects of clinical chytridiomycosis in amphibians include disorders of cutaneous osmoregulation and disruption of the ability to rehydrate, which can lead to decreased host fitness or mortality. Less attention has been given to physiological responses of hosts where enzootic infections of Batrachochytrium dendrobatidis (Bd) do not cause apparent population declines in the wild. Here, we experimentally tested whether an enzootic strain of Bd causes significant mortality and alters host water balance (evaporative water loss, EWL; skin resistance, R(s); and water uptake, WU) in individuals of 3 Brazilian amphibian species (Dendropsophus minutus, n = 19; Ischnocnema parva, n = 17; Brachycephalus pitanga, n = 15). Infections with enzootic Bd caused no significant mortality, but we found an increase in R(s) in 1 host species concomitant with a reduction in EWL. These results suggest that enzootic Bd infections can indeed cause sub-lethal effects that could lead to reduction of host fitness in Brazilian frogs and that these effects vary among species. Thus, our findings underscore the need for further assessment of physiological responses to Bd infections in different host species, even in cases of sub-clinical chytridiomycosis and long-term enzootic infections in natural populations.

Treatment of poultry litter does not improve performance or carcass lesions in broilers / El tratamiento de la cama no afecta el desempeño ni las lesiones en la canal del pollo de engorde / Desempenho produtivo e lesões na carcaça de frangos de corte não são afetados pelo tratamento da cama de frango

Background: broilers spend most of their lives in contact with litter; litter quality can affect their health and performance. Objective: the effects of litter treatment on performance and carcass lesions were evaluated in five consecutive flocks with 640 male broilers each. Methods: a completely randomized model was used comprising eight treatments and four replicates. The treatments included (1) untreated litter, (2) litter subjected to in-house composting, (3) litter treated (LT) with aluminum sulfate, (4) LT with gypsum, (5) LT with quicklime, (6) LT with dolomitic limestone, (7) LT with zeolite, and (8) LT with charcoal. Chopped elephant-grass hay was used as poultry litter in all flocks. Results: none of the litter treatments were found to influence the performance and carcass lesions of the male broilers in all five flocks. Furthermore, poultry litter treatments were not economically viable. Conclusion: poultry litter treatments did not affect the performance and scores of carcass lesions of male broilers, but increased the cost of poultry production.

Antecedentes: los pollos de engorde pasan la mayoría de su vida en contacto con la cama; la calidad de la cama puede afectar la salud y desempeño del ave. Objetivo: fueron evaluados los efectos de diferentes tratamientos de la cama sobre el desempeño y lesiones en la canal de pollos de engorde durante cinco lotes consecutivos con 640 aves cada uno. Métodos: se empleó un modelo completamente aleatorizado con ocho tratamientos y cuatro repeticiones. Los tratamientos incluyeron (1) cama no tratada, (2) cama sometida a compostaje en el galpón, (3) cama tratada (CT) con sulfato de aluminio, (4) CT con yeso agrícola, (5) CT con cal, (6) CT con calcáreo dolomítico, (7) CT con zeolita y (8) CT con carbón vegetal. Heno de pasto elefante picado fue usado como cama en todos los lotes. Resultado: los tratamientos no influenciaron el desempeño ni las lesiones en la canal de los pollos en ningún lote. Además, ninguno de los tratamientos de las camas fue económicamente viables. Conclusión: el tratamiento de la cama de pollo no solo no afecta el desempeño ni las lesiones en la canal de los pollos sino que eleva los costos de producción de las aves.

Antecedentes: os frangos de corte passam a maioria de suas vidas em contato com a cama e a qualidade desta pode afetar a saúde e o desempenho produtivo da ave. Objetivo: Avaliou-se os efeitos dos tratamentos da cama de frango sobre o desempenho no crescimento e lesões na carcaça de frangos de corte. Métodos: avaliaram-se 640 aves por lote, durante cinco lotes consecutivos, analisaram-se empregando um modelo completamente casualizado com oito tratamentos e quatro repetições. Os tratamentos consistiram de (1) cama não tratada, (2) cama submetida a compostagem no galpão, (3) cama tratada (CT) com sulfato de alumínio, (4) CT com gesso agrícola, (5) CT com cal virgem, (6) CT com calcário dolomítico, (7) CT com zeolita e (8) CT com carvão vegetal. Feno de capim elefante picado foi usado como cama em todos os lotes. Resultado: os diferentes tratamentos não influenciaram o desempenho na produção e as lesões na carcaça dos frangos em nenhum lote, entretanto, os tratamentos da cama foram economicamente inviáveis. Conclusão: o tratamento da cama de frango não afeta o desempenho produtivo e os escores de lesões na carcaça dos frangos de corte, além, eleva os custos da produção avícola.