Influence of temperature variability on the feeding behavior and blood consumption of Triatoma infestans (Hemiptera: Reduviidae).

The transmission and incidence of vector-borne diseases rely on vector distribution and life history traits such as survival, fecundity, and feeding. Since arthropod disease vectors are ectotherms, these vital rates are strongly influenced by temperature. Chagas disease is a neglected tropical disease caused by the protozoan parasite, Trypanosoma cruzi. This parasite is transmitted when the feces of the infected triatomine enter the bloodstream of the host. One of the most important vector-species of this disease in the Southern Cone region of South America is Triatoma infestans. In this study, we evaluated the role of constant and variable environmental temperature on the feeding behavior of T. infestans. Fifth-instar nymphs were acclimatized to 4 thermal treatments comprising 2 temperatures (27 °C and 18 °C) with and without diurnal thermal variability (27 ±â€…5 °C and 18 ±â€…5 °C). Individuals were fed weekly for 7 wk to quantify their feeding. Our results showed lower feeding frequency in nymphs acclimatized to cold temperature compared to those from warmer temperature treatments. However, treatments with thermal variability presented a nonlinear effect on feeding, with an increased feeding rate in the cold, variable treatment and a decreased feeding rate in the warm, variable treatment. Individuals maintained under cold treatments, the variable temperature exhibited a higher feeding rate and the lowest amount of ingested blood among all treatments. Thus, natural diurnal temperature variation cannot be ignored if we are to make more accurate T. cruzi transmission risk predictions now and in the future.

Thermophilic anaerobic digestion of winery effluents in a two-stage process and the effect of the feeding frequency on methane production.

This investigation evaluates a two-stage process to treat highly concentrated winery effluents, including a thermophilic methanogenic stage. The inoculum adaptation, the effect of the organic loading rates on both stages, and the methanogenic reactor's feeding frequency on the process performance were studied. An active thermophilic inoculum was obtained by a one-step temperature increase from 35 to 55 °C. The application of organic loads above 120 kg COD m-3 d-1 in the acidogenic stage ensured the highest acetic acid concentration, while methane production rates as high as 7.1 Nm3 CH4 m-3 d-1 and a yield of 348 L CH4 kg-1 COD were obtained in the thermophilic methanogenic stage using an organic loading rate of 29.9 kg COD m-3 d-1. However, a lower removal of organic matter was observed under that condition. Lower feeding frequencies improved methane productivity and yield, suggesting that this parameter is a useful process optimization tool.

Feeding regimen modulates zebrafish behavior.

Here we show that the feeding regimen modulates zebrafish (Danio rerio) behavior. With regard to the time elapsed between feeding and behavioral evaluation, fish fed 3 h before behavioral evaluation in the novel tank test (NTT) showed decreased activity and a trend toward an anxiolytic reaction (increased use of the upper section of the aquarium) in comparison to fish fed 0.5, 6, 12, 24 or 48 h before testing, although differences were not statistically significant for all comparisons. Activity and use of the upper section of the aquarium did not differ significantly among the other treatments. Regarding feeding frequency, fish fed once a day showed higher anxiety-like behavior (decreased use of the upper section of the aquarium) in comparison to fish fed twice a day, but feeding four or six times per day or only every second day did not result in differences from feeding twice a day. Feeding frequency had no effect on activity level. Metabolically, fish fed once a day presented decreased levels of glucose and glycogen and increased lactate when compared to the regular feeding (fish fed twice a day), suggesting that feeding regimen may modulate carbohydrate metabolism. Mechanistically, we suggest that the metabolic changes caused by the feeding regimen may induce behavioral changes. Our results suggest that the high variability of the results among different laboratories might be related to different feeding protocols. Therefore, if issues pertaining to the feeding regimen are not considered during experiments with zebrafish, erroneous interpretations of datasets may occur.

Feed management of pacu juveniles cultivated in net cages / Manejo alimentar de juvenis de pacu criados em tanques rede

The aim of this work was to evaluate the feed management (feed percentage and feeding frequency) of pacu (Piaractus mesopotamicus) juveniles bred in net cages. To evaluate the feed percentage 2,000 juveniles (12.12±0.51 g) were randomly distributed in 20 cages of 1 m3 (0.8 m3 of useful volume). The fish were fed four times a day (8:00 a.m.; 11:00 a.m.; 2:00 p.m.; and 5:00 p.m.) with 4, 7, 10, 13, and 16% of feed. To evaluate feeding frequency, another 2,000 juveniles (9.56±0.56 g) were randomly distributed in 20 cages of 0.8 m3 of useful volume. The fish were fed one, two, three and four times a day. Due to the feed percentage, significant effects (P0.05) by the feeding frequency. Considering the weight gain and apparent feed conversion of pacu juveniles cultivated in net cages, 8% of feed is recommended regardless of the feeding frequency adopted.

O objetivo do presente trabalho foi avaliar o manejo alimentar (porcentagem de arraçoamento e frequência alimentar) de juvenis de pacu (Piractus mesopotamicus) criados em tanques rede. Para avaliar a porcentagem de arraçoamento foram utilizados 2.000 juvenis (12,12±0,51 g), distribuídos em 20 tanques rede de 0,8 m3 de volume útil, alimentados quatro vezes ao dia (8, 11, 14 e 17 horas), com 4, 7, 10, 13 e 16% de arraçoamento. Para avaliar a frequência alimentar, foram utilizados 2.000 juvenis (9,56±0,56 g), distribuídos em 20 tanques rede com 0,8 m3 de volume útil, alimentados uma, duas, três e quatro vezes ao dia. Observou-se efeito significativo (P0,05) da frequência alimentar sobre os parâmetros zootécnicos, composição centesimal e bioquímicos do sangue. Considerando o ganho de peso e conversão alimentar aparente de juvenis de pacu criados em tanques rede, recomenda-se 8% de arraçoamento, independentemente da frequência alimentar adotada.

Feed management of pacu juveniles cultivated in net cages / Manejo alimentar de juvenis de pacu criados em tanques rede

The aim of this work was to evaluate the feed management (feed percentage and feeding frequency) of pacu (Piaractus mesopotamicus) juveniles bred in net cages. To evaluate the feed percentage 2,000 juveniles (12.12±0.51 g) were randomly distributed in 20 cages of 1 m3 (0.8 m3 of useful volume). The fish were fed four times a day (8:00 a.m.; 11:00 a.m.; 2:00 p.m.; and 5:00 p.m.) with 4, 7, 10, 13, and 16% of feed. To evaluate feeding frequency, another 2,000 juveniles (9.56±0.56 g) were randomly distributed in 20 cages of 0.8 m3 of useful volume. The fish were fed one, two, three and four times a day. Due to the feed percentage, significant effects (P<0.05) were observed for the parameters of weight gain, final length, final biomass, specific growth rate, and apparent feed conversion. The performance parameters, centesimal composition, and blood biochemistry were not influenced (P>0.05) by the feeding frequency. Considering the weight gain and apparent feed conversion of pacu juveniles cultivated in net cages, 8% of feed is recommended regardless of the feeding frequency adopted.(AU)

O objetivo do presente trabalho foi avaliar o manejo alimentar (porcentagem de arraçoamento e frequência alimentar) de juvenis de pacu (Piractus mesopotamicus) criados em tanques rede. Para avaliar a porcentagem de arraçoamento foram utilizados 2.000 juvenis (12,12±0,51 g), distribuídos em 20 tanques rede de 0,8 m3 de volume útil, alimentados quatro vezes ao dia (8, 11, 14 e 17 horas), com 4, 7, 10, 13 e 16% de arraçoamento. Para avaliar a frequência alimentar, foram utilizados 2.000 juvenis (9,56±0,56 g), distribuídos em 20 tanques rede com 0,8 m3 de volume útil, alimentados uma, duas, três e quatro vezes ao dia. Observou-se efeito significativo (P<0,05) para os parâmetros de ganho de peso, comprimento final, biomassa final, e conversão alimentar aparente, em função do percentual de arraçoamento. Não foram observadas influências (P>0,05) da frequência alimentar sobre os parâmetros zootécnicos, composição centesimal e bioquímicos do sangue. Considerando o ganho de peso e conversão alimentar aparente de juvenis de pacu criados em tanques rede, recomenda-se 8% de arraçoamento, independentemente da frequência alimentar adotada.(AU)

Vertical flow-constructed wetlands for domestic wastewater treatment under tropical conditions: effect of different design and operational parameters.

This study assessed the treatment of domestic wastewater to find the optimum vertical flow-constructed wetland (VFCW) configuration under tropical conditions. Eight pilot-scale configurations units were studied to compare between fine sand and medium gravel used as substrate, two feeding frequencies (20 pulses d-1 and 10 pulses d-1), and the presence or absence of tropical plants (Heliconia psittacorum). The results showed that the sand beds were significantly more efficient in the removal of organic matter, ammonia nitrogen, and total suspended solids than gravel beds, presenting average removal rates of 48 and 24 g m-2 d-1 of COD; 35 and 16 g m-2 d-1 of BOD5; 7 and 4 g m-2 d-1 of [Formula: see text]; 9 and 0 g m-2 d-1 for sand and gravel, respectively. The oxygen consumption rates were calculated and a value of 65 g m-2 d-1 was obtained for sand beds while for the gravel beds the consumption rate was 30 g m-2 d-1. The assessment of different kinds of nitrogen showed interesting dynamics in the nitrification processes. The presence of H. psittacorum showed positive effects in the total nitrogen (TN) removal. The different loading frequencies applied did not show significant statistical differences in the removal of the tested contaminants. Preliminary results were found in the pathogen removal, where the sand is favorable as the substrate. This work represents the first step in the research of optimum VFWC design and operation parameters for Colombia as well as the use of plants of the genus Heliconia.

Feeding frequency and growth performance of juvenile pink shrimp ([farfantepenaeus paulensis) / Frequência de oferta alimentar e desempenho zootécnico de juvenis do camarão rosa (farfantepenaeus paulensis)

It is generally believed that increasing feeding frequency has immediate benefits, including reduced nutrient leaching and increased shrimp growth. In this context, the aim this work was to evaluate the effect of feeding frequency in growth performance of Farfantepenaeus paulensis. Juveniles of Farfantepenaeus paulensis were grown for 30 days in pen enclosures, at a stocking density of 5 shrimp/m2. The shrimp were fed on feeding trays at a rate of 8% of their biomass per day, with treatments of one, two, three and four times per day, with four replicates each. The results showed no differences (5% probability) in biomass gain of F. paulensis when feed was offered two, three or four times per day. However, it was observed that the once a day frequency had a negative influence on weight gain for this species of shrimp. We conclude that the supply of food with 35% crude protein twice a day is sufficient for the growth of F paulensis. Feeding frequency of three or four times can provide increased spending in the cultivation of juveniles of this species.

Acredita-se que uma frequência maior de alimentação traz benefícios imediatos, incluindo a redução da lixiviação de nutrientes e o aumento do crescimento do camarão. Nesse contexto, o objetivo do presente trabalho foi avaliar o efeito de diferentes frequências de oferta de alimento sobre o crescimento de Farfantepenaeus paulensis. Juvenis de Farfantepenaeus paulensis foram criados por 30 dias em tanques-rede, na densidade de estocagem de cinco camarões/m 2. Os camarões foram alimentados em comedouros com 8% da sua biomassa/dia, ofertados em parcelamentos de uma, duas, três e quatro vezes ao dia, com quatro repetições para cada tratamento. Os resultados mostraram que não ocorreram diferenças (5% de probabilidade) no ganho de biomassa de F. paulensis quando a frequência alimentar foi de duas, três ou quatro vezes ao dia. No entanto, os dados indicam que a frequência alimentar de uma vez ao dia interferiu negativamente no ganho de peso dessa espécie. Conclui-se que o fornecimento de ração com 35% de proteína bruta duas vezes ao dia é suficiente para o crescimento de F paulensis. O fornecimento de alimento três ou quatro vezes ao dia poderia acarretar maiores gastos no manejo de juvenis dessa espécie.

Feeding frequency and growth performance of juvenile pink shrimp (Farfantepenaeus paulensis) / Frequência de oferta alimentar e desempenho zootécnico de juvenis do camarão rosa (Farfantepenaeus paulensis)

It is generally believed that increasing feeding frequency has immediate benefits, including reduced nutrient leaching and increased shrimp growth. In this context, the aim this work was to evaluate the effect of feeding frequency in growth performance of Farfantepenaeus paulensis. Juveniles of Farfantepenaeus paulensis were grown for 30 days in pen enclosures, at a stocking density of 5 shrimp/m2. The shrimp were fed on feeding trays at a rate of 8% of their biomass per day, with treatments of one, two, three and four times per day, with four replicates each. The results showed no differences (5% probability) in biomass gain of F. paulensis when feed was offered two, three or four times per day. However, it was observed that the once a day frequency had a negative influence on weight gain for this species of shrimp. We conclude that the supply of food with 35% crude protein twice a day is sufficient for the growth of F paulensis. Feeding frequency of three or four times can provide increased spending in the cultivation of juveniles of this species.(AU)

Acredita-se que uma frequência maior de alimentação traz benefícios imediatos, incluindo a redução da lixiviação de nutrientes e o aumento do crescimento do camarão. Nesse contexto, o objetivo do presente trabalho foi avaliar o efeito de diferentes frequências de oferta de alimento sobre o crescimento de Farfantepenaeus paulensis. Juvenis de Farfantepenaeus paulensis foram criados por 30 dias em tanques-rede, na densidade de estocagem de cinco camarões/m 2. Os camarões foram alimentados em comedouros com 8% da sua biomassa/dia, ofertados em parcelamentos de uma, duas, três e quatro vezes ao dia, com quatro repetições para cada tratamento. Os resultados mostraram que não ocorreram diferenças (5% de probabilidade) no ganho de biomassa de F. paulensis quando a frequência alimentar foi de duas, três ou quatro vezes ao dia. No entanto, os dados indicam que a frequência alimentar de uma vez ao dia interferiu negativamente no ganho de peso dessa espécie. Conclui-se que o fornecimento de ração com 35% de proteína bruta duas vezes ao dia é suficiente para o crescimento de F paulensis. O fornecimento de alimento três ou quatro vezes ao dia poderia acarretar maiores gastos no manejo de juvenis dessa espécie.(AU)

Oral health and feeding frequency of preschool children in a city in northern Brazil / Perfil da saúde bucal e frequência alimentar de crianças na fase pré-escolar em um município do Norte do Brasil

Oral health and healthy eating habits are related to socioeconomic and cultural conditions of the population and imply the biopsychosocial health of the individual. This study investigated the oral health and feeding frequency of children attending a daycare in the municipality of Ananindeua, Pará State, northern Brazil. This was a cross-sectional study, quantitative and qualitative, descriptive, involving the examination of the oral cavity of children and questionnaires to parents, caregivers and those responsible for the daycare. Forty-seven children aged one to six years participated in this study; most were girls (57.5%). The daycare had no specific place for tooth brushing that was performed only once daily, without flossing. It was reported by parents that 48.94% of children have never visited a dentist. On examination of the oral cavity we observed carious lesion (51.10%), dental calculus (42.55%), fluorosis (10.64%) and gingivitis (2.13%). It was found that the children had 3 or more meals and had the habit of consuming cariogenic foods such as soft drinks, candy and/or gum, even not being provided by the daycare. Most of the children had at least one decayed tooth, and the daycare offered a healthy diet, but the children had the habit of eating cariogenic foods.

A saúde bucal e os hábitos alimentares saudáveis estão relacionados às condições socioeconômicas e culturais da população e implicam na saúde biopsicossocial do indivíduo. Este estudo buscou analisar as condições de saúde bucal e frequência alimentar de crianças matriculadas em uma creche no município de Ananindeua-PA, Norte do Brasil. Foi um estudo transversal, quanti-qualitativo, descritivo, envolvendo o exame da cavidade bucal das crianças e aplicação de questionários para os genitores, cuidadores e responsáveis da creche. Participaram 47 crianças na faixa etária de um a seis anos de idade, sendo a maioria meninas (57,5%). Foi verificado que a creche não possuía escovódromo e que a escovação dos dentes era realizada, apenas, uma vez ao dia, sem o uso do fio dental. Foi relatado pelos pais que 48,94% das crianças nunca foram ao dentista. No exame da cavidade oral foram observadas lesão cariosa (51,10%), cálculo dental (42,55%), fluorose (10,64%) e gengivite (2,13%). Foi verificado que as crianças realizavam três ou mais refeições e tinham o hábito de consumir alimentos cariogênicos como refrigerantes, balas e/ou chicletes, mesmo não sendo oferecidos pela creche. Foi observado que a maioria das crianças apresentou pelo menos um dente cariado e que a creche oferecia alimentação saudável.

Efeito do manejo alimentar no desempenho do matrinxã Brycon amazonicus em tanques de cultivo / Effect of the feed management on performance of Matrinxã Brycon amazonicus in rearing ponds

O objetivo deste estudo foi avaliar o efeito do horário, taxa e freqüência de alimentação no desempenho do matrinxã (Brycon amazonicus) em tanques de cultivo. O trabalho foi realizado no Centro de Aqüicultura da UNESP, Jaboticabal, SP, no período de outubro de 1997 a janeiro de 1998 sendo realizados três ensaios, em tanques de 200m² subdivididos em 4 de 50 m². No ensaio I foram medidos em 3 períodos (manhã-m; meio do dia-md e tarde-t) o consumo de ração, índice de ingestão, tempo de saciação e velocidade de ingestão em peixes com peso médio de 232,13 g, alimentados com ração extrusada (32 por cento de PB). Não foi observada diferença significativa nos parâmetros analisados. No ensaio II, em peixes com peso médio de 233,98 g, foi medido o consumo médio de ração, em intervalos de duas horas, das 07 às 19 horas. O maior consumo ocorreu quando o matrinxã foi alimentado às 17 horas. No ensaio III, durante 57 dias, os peixes foram alimentados uma vez ao dia (m); uma vez ao dia (t); duas vezes ao dia(m/t) e três vezes ao dia (m,md,t). Peixes com peso médio inicial de 322,25 g receberam ração com 32 por cento de PB, na quantidade de 2 por cento do PV. Não foram observadas diferenças significativas no ganho de peso diário (3,17; 2,80; 3,04 e 2,81 g) e na conversão alimentar aparente (2,11; 2,48; 2,16 e 2,31:1). Concluiu-se que a freqüência de alimentação de uma vez ao dia, em qualquer horário, mostrou ser suficiente.

The objective of this study was the identification of effect of period, number of meals, ration feed and frequency of feeding on performance of Matrinxã Brycon amazonicus. The work was carried out on the Aquaculture Center of UNESP in Jaboticabal, SP. The observations were accomplished in three stages, from October 1997 to January 1998 in 16 ponds of 50m². In the first stage it was analyzed the feed consumption, ingestion index and satiation time. Fishes with initial average weight of 232.13g were fed extruded ration of CP 32 percent in three different periods of the day: morning, noon and afternoon. No significant differences were observed. In second stage the feed consumption was observed in two hours intervals from 7 AM to 7 PM. Fishes previous mean weight of 233.98g was used. The statistical analysis demonstrated that the greater consumption happened when the matrinxã was fed at 5 PM. In the third stage feeding frequency was tested (once a day: in the morning; once a day: in the afternoon; twice a day, in the morning and afternoon; three times a day: in the morning, noon and afternoon) during 57 days. Fishes with initial average weight of 322.25 g were fed extruded commercial pellets with 32 percent of CP at a 2 percent biomass rate. No statistical differences were found in weight daily gain (3.17; 2.80; 3.04; and 2.81g) and in food conversion rate (2.11; 2.48; 2.16 and 2.31:1). In order to support growth the results showed that it is enough to feed matrinxã once a day despite the feeding time.

Efeito do manejo alimentar no desempenho do matrinxã Brycon amazonicus em tanques de cultivo

The objective of this study was the identification of effect of period, number of meals, ration feed and frequency of feeding on performance of Matrinxã Brycon amazonicus. The work was carried out on the Aquaculture Center of UNESP in Jaboticabal, SP. The observations were accomplished in three stages, from October 1997 to January 1998 in 16 ponds of 50m². In the first stage it was analyzed the feed consumption, ingestion index and satiation time. Fishes with initial average weight of 232.13g were fed extruded ration of CP 32% in three different periods of the day: morning, noon and afternoon. No significant differences were observed. In second stage the feed consumption was observed in two hours intervals from 7 AM to 7 PM. Fishes previous mean weight of 233.98g was used. The statistical analysis demonstrated that the greater consumption happened when the matrinxã was fed at 5 PM. In the third stage feeding frequency was tested (once a day: in the morning; once a day: in the afternoon; twice a day, in the morning and afternoon; three times a day: in the morning, noon and afternoon) during 57 days. Fishes with initial average weight of 322.25 g were fed extruded commercial pellets with 32% of CP at a 2% biomass rate. No statistical differences were found in weight daily gain (3.17; 2.80; 3.04; and 2.81g) and in food conversion rate (2.11; 2.48; 2.16 and 2.31:1). In order to support growth the results showed that it is enough to feed matrinxã once a day despite the feeding time.

O objetivo deste estudo foi avaliar o efeito do horário, taxa e freqüência de alimentação no desempenho do matrinxã (Brycon amazonicus) em tanques de cultivo. O trabalho foi realizado no Centro de Aqüicultura da UNESP, Jaboticabal, SP, no período de outubro de 1997 a janeiro de 1998 sendo realizados três ensaios, em tanques de 200m² subdivididos em 4 de 50 m². No ensaio I foram medidos em 3 períodos (manhã-m; meio do dia-md e tarde-t) o consumo de ração, índice de ingestão, tempo de saciação e velocidade de ingestão em peixes com peso médio de 232,13 g, alimentados com ração extrusada (32% de PB). Não foi observada diferença significativa nos parâmetros analisados. No ensaio II, em peixes com peso médio de 233,98 g, foi medido o consumo médio de ração, em intervalos de duas horas, das 07 às 19 horas. O maior consumo ocorreu quando o matrinxã foi alimentado às 17 horas. No ensaio III, durante 57 dias, os peixes foram alimentados uma vez ao dia (m); uma vez ao dia (t); duas vezes ao dia(m/t) e três vezes ao dia (m,md,t). Peixes com peso médio inicial de 322,25 g receberam ração com 32% de PB, na quantidade de 2% do PV. Não foram observadas diferenças significativas no ganho de peso diário (3,17; 2,80; 3,04 e 2,81 g) e na conversão alimentar aparente (2,11; 2,48; 2,16 e 2,31:1). Concluiu-se que a freqüência de alimentação de uma vez ao dia, em qualquer horário, mostrou ser suficiente.