RESUMO

To date, the treatment for cysticercosis and neurocysticercosis consists of a single oral intake of praziquantel (5-10 mg/kg), which since it is only available as tablets, hinders its administration to pediatric patients. Praziquantel is a poorly water-soluble drug which represents a challenge for its formulation in solution, particularly for the pediatric population. Thus, this study aimed to develop a palatable solution for praziquantel using pharmaceutical-accepted co-solvent systems. A design of experiments approach was applied to identify the optimal conditions for achieving a suitable amount of praziquantel in solution using co-solvent mixtures. Thus, praziquantel solubility increased from 0.38 up to 43.50 mg/mL in the optimized system. A taste masking assay in healthy human volunteers confirmed a successful reduction of drug bitterness after the addition of selected flavors and a sweetener. Stability studies were also conducted at different temperatures (4, 25, and 40 °C) for 12 months Even though the presence of the three known impurities of praziquantel was observed, their amounts never exceeded the acceptance criteria of the USP. Thus, this novel approach should be considered a valuable alternative for further preclinical studies considering the high prevalence of this infection worldwide.

RESUMO

Estrogen has a well-known effect of reducing salt intake in rats. This mini review focuses on recent findings regarding the interaction of estradiol with brain angiotensin II to control increased sodium palatability that occurs as a result of sodium appetite in spontaneously hypertensive rats.

RESUMO

The risk of predation and the costs and benefits of diverse anti-predator strategies can shift across the life stages of an organism. Yet, empirical examples of ontogenetic switches in defense mechanisms are scarce. Anurans represent an alleged exception; previous meta-analytic work suggests that unpalatability of developing anurans is "rare", whereas adult anurans in many lineages are well defended by toxic and/or unpalatable skin secretions. Here, we revisit the question of the unpalatability of anuran young in a meta-analysis of the relative proportion of prey consumed within 922 predation tests, including 135 anuran species. We tested the hypotheses that a predator's propensity to consume anuran young depends on (1) prey family, (2) predator manipulation strategy, and (3) prey ontogenetic stage. We used a binomial mixed model approach with considerations for multiple effect sizes within studies to evaluate the log odds ratio of the proportion of prey consumed by individual predators. Prey consumption was highly variable, but toads (Bufonidae) were consumed in lower proportions. Chewing invertebrates consumed more anuran prey than biting vertebrates. Late stage tadpoles were more vulnerable to predation than other stages of anuran ontogeny. However, more studies are needed to unravel the roles of development and evolutionary history in the chemical ecology of anuran young. This synthesis provides clear meta-analytic evidence that relative unpalatability is an important component in the anti-predator defenses of young in some anuran families, calling into question the degree to which chemically defended anuran families undergo ontogenetic switches in anti-predator strategies.

Assuntos

RESUMO

Estrogens reduce 0.3 M NaCl intake and palatability in a widely used model of essential hypertension, the spontaneously hypertensive rats (SHRs). Here we investigated whether the inhibitory effects of ß-estradiol (E2, 10 µg/kg b.w. subcutaneously for 8 days) on water deprived partially-rehydrated (WD-PR) ovariectomized (OVX) adult female SHRs (fSHRs, n = 4-10/group) are related to interferences on brain angiotensin II AT1 receptors (AT1r). After WD-PR, E2 reduced 0.3 M NaCl intake (1.3 ± 0.6, vs. vehicle: 3.5 ± 1.2 ml/30 min), the number of hedonic responses to intraoral NaCl infusion (57 ± 11, vs. vehicle: 176 ± 32/min), and the relative angiotensin AT1r (Agtr1a) mRNA expression in the hypothalamus. Losartan (AT1r antagonist, 100 µg) intracerebroventricularly in OVX fSHRs treated with vehicle subcutaneously abolished 0.3 M NaCl intake (0.1 ± 0.1 ml/30 min) and only transiently reduced hedonic responses to intraoral NaCl. Losartan combined with E2 decreased the number of hedonic and increased the number of aversive responses to intraoral NaCl and abolished 0.3 M NaCl intake. E2 also reduced the pressor and dipsogenic responses to intracerebroventricular angiotensin II. The results suggest that AT1r activation increases palatability and induces NaCl intake in WD-PR fSHRs. E2 reduced hypothalamic Agtr1a mRNA expression, which may account for the effects of E2 on NaCl intake and palatability and intracerebroventricular angiotensin II-induced pressor and dipsogenic responses in OVX fSHRs. Future studies considering natural fluctuations in estrogen secretion might help to determine the degree of such interference in brain neuronal activity.

Assuntos

RESUMO

The aim of this study was to evaluate the nycterohemeral patterns of ingestive behavior at 24, 48, and 72 h (Trial I) of sheep fed different roughages and the palatability index (Trial II) for sheep and goats fed different roughages used in a semiarid region. In the study, five sources of roughage were evaluated, namely: (1) Nopalea cochenillifera (L.) Salm-Dyck cladodes + urea + sugarcane bagasse (NUB); (2) Opuntia stricta (Haw.) Haw cladodes + urea + sugarcane bagasse (OUB); (3) Tifton hay; (4) corn silage; and (5) sorghum silage. Five Soinga sheep were used and arranged in a 5 × 5 Latin square design in Trial I. Six female Santa Ines sheep and six female Saanen goats were used to study the preferences for different roughages in Trial II, and three tests were carried out to determine the palatability index, comparing two roughage types at a time: test 1 - corn silage versus Nopalea cladodes + urea + sugarcane bagasse (NUB); test 2 - corn silage versus Opuntia cladodes + urea + sugarcane bagasse (OUB); and test 3 - NUB versus OUB. The highest dry matter (DM) intake was for diets composed by NUB. Feeding time (min/d) was higher for sorghum silage (291 min d-1), while rumination time was higher (P < 0.05) for corn silage (604.0 min d-1), sorghum silage (561.7 min d-1), and Tifton hay (529.7 min d-1). No difference (P > 0.05) was observed for feeding, rumination, and idleness time between species (sheep and goats), and there was no roughage × species interaction (P > 0.05). The palatability indexes were 76 and 77% (tests 1 and 2) for NUB and OUB, respectively. Sheep fed with roughage containing cactus cladodes associated with urea and sugarcane bagasse spent less time on ingestion and rumination activities. The ingestive behavior can be evaluated in a period of 48 h, using instantaneous scanning.

Assuntos

RESUMO

Resumen El objetivo de este trabajo fue determinar la palatabilidad de Monstera deliciosa Liebm, Eugenia myrtifolia sims y Justicia carnea lindl en programas de alimentación de mono araña de cabeza negra (Ateles fusciceps robustus). Esta investigación se desarrolló en la Fundación Zoológico Santacruz, localizada en el San Antonio del Tequendama (Colombia). Se utilizaron ocho animales adultos en cautiverio, los cuales tuvieron una ración complementaria. Asimismo, se ofreció forraje producido en el centro de conservación con 60 días de rebrote. Además, se determinó el consumo de forraje verde y materia seca de la planta completa y de cada fracción (hojas y tallos); y se evaluó la relación hoja: tallo y la calidad nutricional de la planta completa y de cada fracción. En el proceso, se empleó un diseño dado completamente al azar y de estadística descriptiva; para ello, se utilizó el programa Infostat®. Se presentaron diferencias entre especies en el consumo de forraje verde y materia seca de la planta completa (p = 0,0001, p < 0,0001, respectivamente) y de las fracciones hoja (p = 0,0002, p = 0,0001, respectivamente) y tallo (p < 0,0001, p < 0,0001, respectivamente). Como resultado, las especies presentaron buena calidad nutricional, siendo mayor en J. carnea, seguida de M. deliciosa y E. myrtifolia y se notó una relación positiva hoja: tallo, aunque se presentaron diferencias (p < 0,0001) entre las especies. Las especies evaluadas presentan potencial para ser utilizadas en los centros de conservación en cautiverio en planes de alimentación para Ateles fusciceps robustus.

Abstract This article aims to determine the palatability of Monstera deliciosa Liebm, Eugenia myrtifolia sims and Justicia carnea lindl in marimonda (Ateles fusciceps robustus) feeding programs. This research was developed at the Santacruz Zoo Foundation, located in San Antonio del Tequendama (Colombia). In the study, eight adult animals in captivity were used, which had a complementary ration. Likewise, forage produced in the conservation center was offered with 60 days of regrowth, the consumption of green forage and dry matter of the complete plant and of each fraction (leaves and stems) was determined. Also, the leaf: stem ratio and the nutritional quality of the complete plant and of each fraction were evaluated. It is worth to mention, a design was used for completely randomized and descriptive statistics, and the Infostat® program was used. There were differences between species in the consumption of green forage and dry matter of the whole plant (p = 0.0001, p < 0.0001, respectively) and of the leaf fractions (p = 0.0002, p = 0.0001, respectively) and stem (p < 0.0001, p < 0.0001, respectively). In the explored case, the species presented good nutritional quality, being higher in J. carnea, followed by M. delicious and E. myrtifolia and positive leaf: stem ratio were apparent, although there were differences (p < 0.0001) between species. The evaluated species have the potential to be used in captive conservation centers as feeding plans for Ateles fusciceps robustus.

RESUMO

The intensity of sucrose (its perceived concentration) and its palatability (positive hedonic valence associated with ingestion) are two taste attributes that increase its attractiveness and overconsumption. Although both sensory attributes covary, in that increases in sucrose concentration leads to similar increases in its palatability, this covariation does not imply that they are part of the same process or whether they represent separate processes. Both these possibilities are considered in the literature. For this reason, we tested whether sucrose's perceived intensity could be separated from its hedonically positive palatability. To address this issue, rats were trained in a sucrose intensity task to report the perceived intensity of a range of sucrose concentrations before and after its palatability was changed using a conditioned taste aversion (CTA) protocol. We found that the subjects' performance remained essentially unchanged, although its palatability was changed from hedonically positive to negative. Overall, these data demonstrate that sucrose's perceived intensity and its positive palatability can be dissociated, meaning that changes of one taste attribute render the other mostly unaffected. Thus, the intensity attribute is sufficient to inform the perceptual judgments of sucrose's concentrations.

Assuntos

RESUMO

ABSTRACT As palatability of medical formulas has been documented as unpleasant, new options are required to improve acceptance and adherence in people with inborn errors of metabolism (IEM). Miracle fruit (Synsepalum dulcificum) has a glycoprotein named miraculin that transforms a sour, bitter taste such as the one found in metabolic formula, into a sweet perception. The objective of this work is to analyze the response in the taste perception of metabolic formula with the use of the miraculin tablets in patients with IEM and healthy adults. To test this hypothesis a prospective, longitudinal, quasi-experimental, analytical study was performed. Patients with IEM and healthy adults were recruited. All participants assessed 3 different liquids (lemon, apple cider vinegar and metabolic formula) before and after the administration of miraculin tablets and completed a questionnaire. The sensory responses were evaluated using hedonic scales, analyzed with nonparametric tests for paired data. Seven patients with IEM and 14 healthy subjects were included. After miraculin intake 57% of patients (Z ≤ -1.89 p= 0.059) and healthy adults (Z≤ -2.31 p= 0.021) had a positive change in their taste perception. The absolute frequency of patients who did not like the metabolic formula decreased from 4 to 1, and in patients who liked it or loved, it increased from 0 to 2 and from 0 to 1 respectively; the frequency of patients who perceived the metabolic formula as indifferent or hated it, did not change. Response in taste perception had a positive change of 57% in both groups. The use of miraculin tablets may improve palatability of metabolic formula.

RESUMEN La palatabilidad de las fórmulas médicas se ha reportado como desagradable, se requieren nuevas opciones para mejorar la aceptación en personas con errores innatos del metabolismo (EIM). La fruta milagrosa (Synsepalum dulcificum) contiene una glucoproteína llamada miraculina que transforma el sabor agrio y amargo en dulce. El objetivo fue analizar la respuesta en la percepción del sabor de la fórmula metabólica con el uso de las tabletas de miraculina en pacientes con EIM y adultos sanos. Se realizó un estudio analítico prospectivo, longitudinal, cuasi-experimental. Los participantes evaluaron la percepción de 3 líquidos (limón, vinagre de manzana y fórmula metabólica) antes y después de la administración de tabletas de miraculina y completaron un cuestionario. Las respuestas sensoriales se evaluaron mediante escalas hedónicas, analizadas con pruebas no paramétricas para datos pareados. Se incluyeron 7 pacientes con EIM y 14 adultos sanos. Después de la miraculina el 57% de los pacientes (Z ≤ -1,89 p= 0,059) y adultos sanos (Z≤ -2,31 p= 0,021) tuvieron un cambio positivo en su percepción del sabor. La frecuencia absoluta de pacientes a los que no les gustó la fórmula disminuyó de 4 a 1, y en quienes les gustó o les encantó, aumentó de 0 a 2 y de 0 a 1 respectivamente; la frecuencia de los pacientes que percibieron la fórmula como indiferente u odiada, no cambió. La respuesta en la percepción del sabor cambió positivamente en el 57% en ambos grupos. El uso de miraculina puede mejorar la palatabilidad de la fórmula metabólica.

Assuntos

RESUMO

The aim of this study was to (i) gain an overview of the protocols of food preference tests in cats through a systematic review, (ii) assess the effects of test duration, time of day, and sex, and (iii) propose a statistical approach based on power analysis to determine sample size and analyze the results. The manuscripts included in this review had marked variations in the number of days (2-56), sample size (9-60 cats), feeding times (2.5-1440 min), and number of meals per day (1-2) during the test. Additionally to the literature review, three palatability tests (lasting 10 days each) were conducted with 40 cats (22 males and 18 females, 1.8 ± 0.16 years, 3.73 ± 0.90 kg) to assess the effects of test duration, time of day, and gender on the results. From the second day of the test, the sensitivity of the results was higher, because on the first day the results in one of the tests differed from the others (p = .0058). There was no difference (p > .05) between times of day (morning vs afternoon) or gender (males vs females) on the results of the feed intake ratio. For a SD of 0.20, p < .05, and delta of 0.10, the minimum number of cats for two-bowl assays is 23 (test power higher than 0.75).The sample size and test duration are critical factors in the decision making by the investigators about the design of food preference tests in cats. The use of a power test is recommended upon planning a food preference test protocol in cats.

Assuntos

RESUMO

Sucrose is attractive to most species in the animal kingdom, not only because it induces a sweet taste sensation but also for its positive palatability (i.e., oromotor responses elicited by increasing sucrose concentrations). Although palatability is such an important sensory attribute, it is currently unknown which cell types encode and modulate sucrose's palatability. Studies in mice have shown that activation of GABAergic LHAVgat+ neurons evokes voracious eating; however, it is not known whether these neurons would be driving consumption by increasing palatability. Using optrode recordings, we measured sucrose's palatability while VGAT-ChR2 transgenic mice performed a brief access sucrose test. We found that a subpopulation of LHAVgat+ neurons encodes palatability by increasing (or decreasing) their activity as a function of the increment in licking responses evoked by sucrose concentrations. Optogenetic gain of function experiments, where mice were able to choose among available water, 3% and 18% sucrose solutions, uncovered that opto-stimulation of LHAVgat+ neurons consistently promoted higher intake of the most palatable stimulus (18% sucrose). In contrast, if they self-stimulated near the less palatable stimulus, some VGAT-ChR2 mice preferred water over 18% sucrose. Unexpectedly, activation of LHAVgat+ neurons increased quinine intake but only during water deprivation, since in sated animals, they failed to promote quinine intake or tolerate an aversive stimulus. Conversely, these neurons promoted overconsumption of sucrose when it was the nearest stimulus. Also, experiments with solid foods further confirmed that these neurons increased food interaction time with the most palatable food available. We conclude that LHAVgat+ neurons increase the drive to consume, but it is potentiated by the palatability and proximity of the tastant.

RESUMO

Despite the importance of hedonic reactions in pig's intake, feed palatability has been typically inferred from preference or acceptance measures. However, these measures are influenced by factors beyond palatability, such as energy density and hunger. The aim of this study was to evaluate palatability responses in pigs to sweet and umami taste at different inclusions levels. Pigs (24 per experiment) were video recorded while exposed in pairs to different sucrose (Exp. 1) or monosodium glutamate (MSG, Exp. 2) solutions over seven consecutive 10 min tests (one concentration per day). In both experiments, palatability was estimated through consumption patterns (consumption time per approaches, CT/A), facial expressions (snout openings and tongue protrusions), and consumption during a brief 2 min period. Data were analyzed by sucrose or MSG concentration. Sucrose concentration affected total intake, producing an inverted-U function and a quadratic relationship with sucrose concentration (P = 0.012). In contrast, CT/A and snout openings showed a dose effect (P < 0.005) with a direct correlation between sucrose concentration and CT/A (R = 0.23, P = 0.033) but not for openings (R = 0.18, P = 0.105) where a quadratic relationship appears (P < 0.001). Tongue protrusions and brief consumption time were not affected by sucrose concentration (P = 0.144 and 0.205, respectively). MSG concentration affected consumption, CT/A, snout openings, and brief consumption time (P < 0.001), with significant (P < 0.001) positive correlations (R = 0.59, 0.56, 0.56, and 0.68), respectively. As with rats, CT/A appears to provide a novel and interesting measure reflecting the palatability of preferred ingredients in pigs. However, brief consumption time and orofacial reactions show less similarity between pigs and rodents. Thus further studies are necessary both to better understand the measurement methods themselves and relationship between hedonic reactions and simple consumption in pigs.

Assuntos

RESUMO

This study aimed to evaluate the effects of including 200 g kg −1 dried distillers grains with solubles (DDGS) to xylanase- and protease-supplemented diets for dogs on kibble properties, digestibility, fecal characteristics, and palatability. Experimental diets consisted of: 0 g kg −1 DDGS without enzymes (0WE), 0 g kg −1 DDGS with xylanase and protease (0XP), 200 g kg −1 DDGS without enzymes (200WE), 200 g kg −1 DDGS with xylanase (200X), 200 g kg −1 DDGS with protease (200P), and 200 g kg −1 DDGS with xylanase and protease (200XP). Kibbles were evaluated for density, extruded size, expansion index, hardness, and uniformity. Six beagle dogs were distributed in a 6×6 Latin square design for analysis of digestibility and fecal characteristics. A palatability assay was also conducted in 16 beagle dogs, comparing the following treatment groups: 0WE vs. 200WE and 0XP vs. 200XP. The results showed that DDGS inclusion had no influence on kibble physical properties and reduced digestibility of dry matter (DM), ether extract after acid hydrolysis, gross energy, and organic matter, regardless of enzyme addition. Moreover, dietary addition of DDGS reduced fecal pH and increased total short-chain fatty acid, acetate, and propionate productions. Fecal odor was increased in dogs fed diets containing DDGS. Regarding palatability, animals preferred diets supplemented with enzymes and without DDGS, and no difference was observed when comparing 0WE and 200WE diets. No changes in the physical properties of kibbles were caused by DDGS inclusion; therefore, it can be used in diet formulation without interfering with the industrial process. Increased production of SCFA and a possible modulation of digestive tract microbiota promoted by DDGS addition may benefit animals. However, at the tested levels, enzymes had no positive effects on diet digestibility. Despite reducing digestibility, DDGS can still be included without enzyme supplementation in low-cost diets for dogs, as nutrient digestibility of the diet remains within acceptable limits for some pet food categories.(AU)

Assuntos

RESUMO

The purpose of this study was to identify predictors of preference for alfalfa hay by equines. A total of 15 quarter horses, at average age and body weight of 10 years and 500 kg were used, respectively. It was conducted an evaluation to identify the preference for alfalfa hay by horses by short-period tests of 10 min. This evaluation was conducted in pairs for each test hay (1-30), available on the market, against each standard (A, B, C), until the completion of all resulting combinations. Alfalfa hays classified as A, B and C, contained on average 22.88, 17.78 and 13.16% of crude protein, respectively. The evaluated variables were constituted by ethological, morphological, microbiological, bromatological and biological analysis. The horses showed a preference for the type A of alfalfa hay, followed by type B and C. The preference for alfalfa hay type A can be predicted by the equation: Pref . A = 98.19 + 1.61 ( acid detergent fiber ) + 1.53 ( in vitro dry matter digestibility ) + 18.54 ( stem thickness ) 0.03 ( acid detergent fiber x in vitro dry matter digestibility ) 0.02 ( acid detergent fiber x stem thickness ) 0.28 ( in vitro dry matter digestibility x stem thickness ) , r 2 = 0.31 , P = 0.0044. It was concluded that horses showed preference to alfalfa hay, wherein the best type A bales. Therefore to predict of preference of the equines for high quality alfalfa hay it's necessary to select bales with lower values of stem thickness and fiber in acid detergent, as well as presenting high level of dry matter digestibility.

O objetivo com este estudo foi identificar preditores de preferência pelo feno de alfafa pelos cavalos. Foram utilizados 15 cavalos da raça quarto de milha, com idade média e peso corporal de 10 anos e 500 kg, respectivamente. Foi realizada uma avaliação para identificar a preferência pelo feno de alfafa por cavalos em testes de curto período de 10 min. Esta avaliação foi realizada em pares para cada teste de feno (1-30) em relação a cada padrão (A, B, C), até a conclusão de todas as combinações resultantes. As variáveis avaliadas foram constituídas por análises etológicas, morfológicas, microbiológicas, bromatológicas e biológicas. Os cavalos mostraram preferência pelo tipo A de feno de alfafa, seguido do tipo B e C. A preferência pelo tipo A do feno de alfafa pode ser predita pela equação: Pref . A = 98.19 + 1 , 61 ( ADF ) + 1 , 53 ( IVDMD ) + 18 , 54 ( ST ) 0 , 03 ( ADFxIVDMD ) 0 , 02 ( ADFxST ) 0 , 28 ( IVDMDxST ) , r 2 = 0,31 , P = 0,0044. Concluiu- se que os cavalos mostraram preferência ao feno de alfafa, em que os melhores fardos do tipo A podem ser identificados selecionando-os porque eles contêm baixas quantidades de espessura do caule e fibra de detergente ácido, bem como altos níveis de digestibilidade da matéria seca in vitro.

Assuntos

RESUMO

The purpose of this study was to identify predictors of preference for alfalfa hay by equines. A total of 15 quarter horses, at average age and body weight of 10 years and 500 kg were used, respectively. It was conducted an evaluation to identify the preference for alfalfa hay by horses by short-period tests of 10 min. This evaluation was conducted in pairs for each test hay (1-30), available on the market, against each standard (A, B, C), until the completion of all resulting combinations. Alfalfa hays classified as A, B and C, contained on average 22.88, 17.78 and 13.16% of crude protein, respectively. The evaluated variables were constituted by ethological, morphological, microbiological, bromatological and biological analysis. The horses showed a preference for the type A of alfalfa hay, followed by type B and C. The preference for alfalfa hay type A can be predicted by the equation: Pref . A = 98.19 + 1.61 ( acid detergent fiber ) + 1.53 ( in vitro dry matter digestibility ) + 18.54 ( stem thickness ) 0.03 ( acid detergent fiber x in vitro dry matter digestibility ) 0.02 ( acid detergent fiber x stem thickness ) 0.28 ( in vitro dry matter digestibility x stem thickness ) , r 2 = 0.31 , P = 0.0044. It was concluded that horses showed preference to alfalfa hay, wherein the best type A bales. Therefore to predict of preference of the equines for high quality alfalfa hay it's necessary to select bales with lower values of stem thickness and fiber in acid detergent, as well as presenting high level of dry matter digestibility.(AU)

O objetivo com este estudo foi identificar preditores de preferência pelo feno de alfafa pelos cavalos. Foram utilizados 15 cavalos da raça quarto de milha, com idade média e peso corporal de 10 anos e 500 kg, respectivamente. Foi realizada uma avaliação para identificar a preferência pelo feno de alfafa por cavalos em testes de curto período de 10 min. Esta avaliação foi realizada em pares para cada teste de feno (1-30) em relação a cada padrão (A, B, C), até a conclusão de todas as combinações resultantes. As variáveis avaliadas foram constituídas por análises etológicas, morfológicas, microbiológicas, bromatológicas e biológicas. Os cavalos mostraram preferência pelo tipo A de feno de alfafa, seguido do tipo B e C. A preferência pelo tipo A do feno de alfafa pode ser predita pela equação: Pref . A = 98.19 + 1 , 61 ( ADF ) + 1 , 53 ( IVDMD ) + 18 , 54 ( ST ) 0 , 03 ( ADFxIVDMD ) 0 , 02 ( ADFxST ) 0 , 28 ( IVDMDxST ) , r 2 = 0,31 , P = 0,0044. Concluiu- se que os cavalos mostraram preferência ao feno de alfafa, em que os melhores fardos do tipo A podem ser identificados selecionando-os porque eles contêm baixas quantidades de espessura do caule e fibra de detergente ácido, bem como altos níveis de digestibilidade da matéria seca in vitro.(AU)

Assuntos

RESUMO

The objective of this study was to evaluate different chemical stimulants with different flavours such as acids (citric and acetic), sweet (sucrose) and salty (sodium chloride) applied to cotton rolls and compare their effects on the volume, pH and protein concentrations of the saliva collected and the behaviour of dogs during sampling management. As an additional objective, serum cortisol concentrations of saliva samples obtained with or without citric acid and with or without previous pH adjustment were compared. Five clinically healthy were randomly assigned to one of 5 treatments with cottons with different substances: 1) control, 2) citric acid, 3) acetic acid, 4) sodium chloride, 5) sucrose. Each dog received one treatment per day, and in 5 days, all dogs were tested with the five treatments. On each day, cottons were applied to dogs at times 0, 20, 40, 60 and 80 minutes. The cottons with citric acid generated more volume than the rest of the treatments (p<0.0001), and sodium chloride generated more volume than the control and acetic acid (p≤0.03). Cottons with citric acid generated lower pH of saliva than the rest of the treatments (p<0.0001). Cottons with acetic acid generated lower pH than control, sodium chloride and sucrose (p<0.0001). There were no differences in cortisol concentrations between the control samples and those obtained with citric acid, nor between these same samples with and without pH adjusted with buffer. The concentration of proteins in saliva and excitement degree did not change with treatment. Citric acid was more palatable than the rest of the treatments (p<0.0001). Sodium chloride and sucrose were more palatable than control (p<0.05). In conclusion, citric acid was the chemical stimulant that generated greater volume of saliva and greater palatability in dogs. Although the pH of the saliva obtained with citric acid was clearly acidic, its acidic pH did not affect the determination of cortisol by chemiluminescence or RIA. Sodium chloride and sucrose allowed to obtain high volumes of saliva and were more palatable than the control, which can be other interesting options to obtain saliva in case of not being able to use citric acid.

RESUMO

The study reported four experiments aiming to test the effects of the pre-exposure schedule and water deprivation on the generalization of a conditioned taste aversion in rats, with a particular focus on testing whether or not the concurrent schedule might enhance generalization. In two experiments, non-water-deprived rats received concurrent, intermixed, or blocked exposure to a sweet-acid solution and a salty-acid solution before conditioning of one of these compounds and testing of both flavors. During pre-exposure, the rats consumed a greater amount of the sweet-acid solution than the salty-acid solution (Experiments 1 and 2), consumption of the former increasing during pre-exposure while consumption of the latter decreased (Experiment 1). Furthermore, consumption of the salty-acid solution was lower during concurrent than intermixed or blocked pre-exposure (Experiment 1 and 2) while consumption of the sweet-acid solution was greater during intermixed than concurrent or blocked pre-exposure (Experiment 1). It is discussed whether the pre-exposure schedule might modify stimulus perception beyond the mere enhancement of stimulus differentiation, by, for instance, affecting the palatability of gustatory stimuli. Evidence for enhanced generalization after concurrent pre-exposure was not found for either deprived (Experiments 1, 2, and 3) or non-deprived rats (Experiments 3 and 4), with deprivation leading to a general increase in consumption of both the conditioned and test flavors. This then raised the question of whether or not concurrent pre-exposure to flavors always increases generalization between them. The present study highlights the importance of this issue for various accounts of perceptual learning.

RESUMO

Although the palatability of sucrose is the primary reason for why it is over consumed, it is not well understood how it is encoded in the nucleus accumbens shell (NAcSh), a brain region involved in reward, feeding, and sensory/motor transformations. Similarly, untouched are issues regarding how an external auditory stimulus affects sucrose palatability and, in the NAcSh, the neuronal correlates of this behavior. To address these questions in behaving rats, we investigated how food-related auditory cues modulate sucrose's palatability. The goals are to determine whether NAcSh neuronal responses would track sucrose's palatability (as measured by the increase in hedonically positive oromotor responses lick rate), sucrose concentration, and how it processes auditory information. Using brief-access tests, we found that sucrose's palatability was enhanced by exteroceptive auditory cues that signal the start and the end of a reward epoch. With only the start cue the rejection of water was accelerated, and the sucrose/water ratio was enhanced, indicating greater palatability. However, the start cue also fragmented licking patterns and decreased caloric intake. In the presence of both start and stop cues, the animals fed continuously and increased their caloric intake. Analysis of the licking microstructure confirmed that auditory cues (either signaling the start alone or start/stop) enhanced sucrose's oromotor-palatability responses. Recordings of extracellular single-unit activity identified several distinct populations of NAcSh responses that tracked either the sucrose palatability responses or the sucrose concentrations by increasing or decreasing their activity. Another neural population fired synchronously with licking and exhibited an enhancement in their coherence with increasing sucrose concentrations. The population of NAcSh's Palatability-related and Lick-Inactive neurons were the most important for decoding sucrose's palatability. Only the Lick-Inactive neurons were phasically activated by both auditory cues and may play a sentinel role monitoring relevant auditory cues to increase caloric intake and sucrose's palatability. In summary, we found that auditory cues that signal the availability of sucrose modulate its palatability and caloric intake in a task dependent-manner and had neural correlates in the NAcSh. These findings show that exteroceptive cues associated with feeding may enhance positive hedonic oromotor-responses elicited by sucrose's palatability.

RESUMO

This study aimed to mask fluconazole (FLU) taste and improve its rheological properties by an efficient process of cyclodextrin complexation. For this, hot-melt extrusion (HME) was used to obtain extrudates composed of FLU, hydroxypropylcellulose, and one of two different cyclodextrins (ß-cyclodextrin or hydroxypropyl-ß-cyclodextrin) maintaining the drug:cyclodextrin molar ratio at 1:0.3 or 1:0.2, respectively. Samples were characterized by physicochemical tests, palatability using e-tongue and antifungal assays. Drug stability was preserved after HME, according to spectroscopy test (correlation coefficient >0.9) and HPLC-assay (100-107%). Flowability was improved in HME systems with compressibility of <12%. Similarly, floodability exhibited significant enhancement (dispersibility <10%). Whereas extrudates of FLU containing only the polymeric matrix led to a slow drug dissolution efficiency (18.6%) and a partial drug taste masking; extrudates containing cyclodextrin accelerated FLU dissolution (dissolution efficiency approx. 30%) and provided a complete drug taste masking. Moreover, HME process could produce drug complexes with high complexation efficiency and preserve its antifungal activity.

Assuntos

RESUMO

This work aimed at obtaining an optimized itraconazole (ITZ) solid oral formulation in terms of palatability and dissolution rate by combining different polymers using hot melt extrusion (HME), according to a simplex centroid mixture design. For this, the polymers Plasdone® (poly(1-vinylpyrrolidone-co-vinyl acetate) [PVP/VA]), Klucel® ELF (2-hydroxypropyl ether cellulose [HPC]), and Soluplus® (SOL, polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol) were processed using a laboratory HME equipment operating without recirculation at constant temperature. Samples were characterized by physicochemical assays, as well as dissolution rate and palatability using an e-tongue. All materials became homogeneous and dense after HME processing. Thermal and structural analyses demonstrated drug amorphization, whereas IR spectroscopy evidenced drug stability and drug-excipient interactions in HME systems. Extrudates presented a significant increase in dissolution rate compared to ITZ raw material, mainly with formulations containing PVP/VA and HPC. A pronounced improvement in taste masking was also identified for HME systems, especially in those containing higher amounts of SOL and HPC. Data showed polymers act synergistically favoring formulation functional properties. Predicted best formulation should contain ITZ 25.0%, SOL 33.2%, HPC 28.9%, and PVP/VA 12.9% (w/w). Optimized response considering dissolution rate and palatability reinforces the benefit of polymer combinations.

Assuntos

RESUMO

Adaptive radiation is characterized by rapid diversification that is strongly associated with ecological specialization. However, understanding the evolutionary mechanisms fueling adaptive diversification requires a detailed knowledge of how natural selection acts at multiple life-history stages. Butterflies within the genus Adelpha represent one of the largest and most diverse butterfly lineages in the Neotropics. Although Adelpha species feed on an extraordinary diversity of larval hosts, convergent evolution is widespread in this group, suggesting that selection for mimicry may contribute to adaptive divergence among species. To investigate this hypothesis, we conducted predation studies in Costa Rica using artificial butterfly facsimiles. Specifically, we predicted that nontoxic, palatable Adelpha species that do not feed on host plants in the family Rubiaceae would benefit from sharing a locally convergent wing pattern with the presumably toxic Rubiaceae-feeding species via reduced predation. Contrary to expectations, we found that the presumed mimic was attacked significantly more than its locally convergent model at a frequency paralleling attack rates on both novel and palatable prey. Although these data reveal the first evidence for protection from avian predators by the supposed toxic, Rubiaceae-feeding Adelpha species, we conclude that imprecise mimetic patterns have high costs for Batesian mimics in the tropics.

Assuntos