Ecotoxicological risks of calcium nitrate exposure to freshwater tropical organisms: Laboratory and field experiments.

This study aimed to analyze laboratory and field data to assess the ecotoxicological risks of calcium nitrate exposure to freshwater tropical biota. Short-term laboratorial tests resulted in estimated EC50 values of 76.72 (67.32-86.12)mg N-NO3₋ L(-1) for C. silvestrii and 296.46 (277.16-315.76) mg N-NO3₋ L(-1) for C. xanthus. Long-term laboratorial tests generated IC25 values of 5.05 (4.35-5.75) and 28.73 (26.30-31.15) mg N-NO3₋ L(-1) for C. silvestrii and C. xanthus, respectively. The results from in situ mesocosm experiments performed in the Ibirité reservoir (a tropical eutrophic urban water body located in SE Brazil) indicated that C. silvestrii and C. xanthus were not under severe deleterious acute impact due to the treatment because the higher nitrate concentrations determined were 5.2 mg N-NO3₋ L(-1) (t=24 h; sediment-water interface) and 17.5 mg N-NO3₋ L(-1) (t=600 h; interstitial water). However, an abrupt decrease in the densities of Cyanophyceae members and other benthic taxa was observed. In summary, the present work contributes greatly to the toxicity data linked to two taxonomically distinct organisms that have never been screened for calcium nitrate sensitivity. Furthermore, considering the problem of the management and restoration of eutrophic environments, our study reports a comprehensive field assessment that allows the elucidation of the possible toxic impacts caused by the addition of calcium nitrate (a remediation technique) on aquatic and benthic organisms as well as the implications on the aquatic ecosystem as a whole, which may greatly allow expanding the current knowledgebase on the topic.

Genetic diversity based on multivariate techniques in elephant grass genotypes for bioenergy.

The use of biomass for energy production constitutes a promising strategy that warrants the search for new sources of biomass. Elephant grass has been gaining notoriety due to its high dry matter yield and rapid growth. The present study was carried out to quantify the genetic divergence of nine elephant grass half-sib families in order to identify genotypes with greater genetic divergence and productive potential for hybridization, using the hierarchical clustering methodology based on principal components. Half-sib families were generated using genotypes from the Active Germplasm Bank of Elephant Grass. The experiment was laid out in a randomized-block design with nine half-sib families, three replicates, and eight plants per plot. A total of 216 genotypes of elephant grass were evaluated. Principal component (PC), biplot, and hierarchical clustering analyses for diversity estimation were conducted using R software. The first two PCs of biplot analysis accounted for 64% of the cumulative variation. Dry matter yield was the most important trait for genotype discrimination (0.89), followed by plant height (0.67) and stem diameter (0.61) in PC1. In this analysis, the distances between accessions were considered and there were no family links, which indicates the existence of wide variability within the evaluated families, since genotypes belonging to the same family were not grouped together, but rather distributed into different groups. Crosses between genotypes of group three and genotypes of groups one and two are recommended for the development of high-yielding genotypes when aiming at energy production.

Harmonised framework for ecological risk assessment of sediments from ports and estuarine zones of North and South Atlantic.

This paper presents a harmonised framework of sediment quality assessment and dredging material characterisation for estuaries and port zones of North and South Atlantic. This framework, based on the weight-of-evidence approach, provides a structure and a process for conducting sediment/dredging material assessment that leads to a decision. The main structure consists of "step 1" (examination of available data); "step 2" (chemical characterisation and toxicity assessment); "decision 1" (any chemical level higher than reference values? are sediments toxic?); "step 3" (assessment of benthic community structure); "step 4" (integration of the results); "decision 2" (are sediments toxic or benthic community impaired?); "step 5" (construction of the decision matrix) and "decision 3" (is there environmental risk?). The sequence of assessments may be interrupted when the information obtained is judged to be sufficient for a correct characterisation of the risk posed by the sediments/dredging material. This framework brought novel features compared to other sediment/dredging material risk assessment frameworks: data integration through multivariate analysis allows the identification of which samples are toxic and/or related to impaired benthic communities; it also discriminates the chemicals responsible for negative biological effects; and the framework dispenses the use of a reference area. We demonstrated the successful application of this framework in different port and estuarine zones of the North (Gulf of Cádiz) and South Atlantic (Santos and Paranaguá Estuarine Systems).

Integrated sediment quality assessment in Paranaguá Estuarine System, Southern Brazil.

Sediment quality from Paranaguá Estuarine System (PES), a highly important port and ecological zone, was evaluated by assessing three lines of evidence: (1) sediment physical-chemical characteristics; (2) sediment toxicity (elutriates, sediment-water interface, and whole sediment); and (3) benthic community structure. Results revealed a gradient of increasing degradation of sediments (i.e. higher concentrations of trace metals, higher toxicity, and impoverishment of benthic community structure) towards inner PES. Data integration by principal component analysis (PCA) showed positive correlation between some contaminants (mainly As, Cr, Ni, and Pb) and toxicity in samples collected from stations located in upper estuary and one station placed away from contamination sources. Benthic community structure seems to be affected by both pollution and natural fine characteristics of the sediments, which reinforces the importance of a weight-of-evidence approach to evaluate sediments of PES.

Concentration of lead in mineral salt mixtures used as supplements in cattle food.

We measured lead concentrations in samples of mineral salt mixtures used in cattle feed in the states of Paraná and São Paulo, Brazil. Lead content was determined spectrometrically by the atomic plasma induction method. Of the 30 samples analyzed, 9 had lead concentrations above 30 ppm (range 35.7 to 284.5 ppm) which is the maximum concentration recommended by the National Research Council (NRC 1980). These findings show the necessity for careful industrial monitoring because some mineral mixtures contain sufficient lead to cause toxicity.

[Substituted thiazolidinediones and thioxothiazolidinones: synthesis and structure]. / Thiazolidinediones et thioxothiazolidinones substituées: synthèse et étude structurale.

Synthesis and physico-chemical properties of 3-(4-bromobenzyl)-, 3-(4-chlorobenzyl)-5-arylidene-thiazolidine-2,4-diones and 3-(4-chlorobenzyl)-4-thioxo-5-arylidene-thiazolidin-2- ones are described. Twelve new products were synthesized by the aldolisation-crotonisation reaction from aromatic aldehydes and N-alkylated thiazolidinediones or thioxothiazolidinones. Seven compounds were preliminary tested for their bacteriostatic activity.

Desempenho e termorregulação de porcas lactantes alojadas em diferentes localizações no interior de um galpão com sistema de resfriamento evaporativo em ambiente tropical / Performance and thermoregulation of lactating sows housed in different locations inside a shed with an evaporative cooling system in a tropical environment

The effects of housing lactating sows at different locations in a shed with evaporative cooling system (ECS) on their thermoregulation and reproductive and productive performance of the sow and the litter in summer were determined. 34 females were used in the three lines of cages at these locations: near the pad cooling; in the middle of the shed and near the exhaust fans. The air temperature and the temperature and humidity index (THI) were lower near the pad cooling (22.38ºC, 71.84) than the middle (24.56ºC, 74.82) and near the exhaust fans (25.00°C, 75.62). Respiratory rate, rectal and surface temperatures were lower in sows near the pad cooling (43.67 breaths.min -1 , 38.40°C; 29.51°C) than in the center (52.04 breaths.min -1 ; 38.48ºC; 32.02ºC) and near the exhaust fans (56.38 breaths.min-1, 38.93ºC; 32.52ºC). The backfat thickness, the weaning-estrus interval and daily average consumption of the sows, number of weaning piglets, corporal mass and daily average gain of the piglets were not influenced by the location of housing in the shed. Lactating sows housed in the middle and near the exhaust fans in the ECS presented increased thermoregulation physiological variables, however, this did not impair the performance.(AU)

Dados de estação meteorológica oficial subestimam o estresse por calor em bovinos leiteiros criados em ambiente tropical / Official meteorological station data underestimate the heat stress on dairy cattle in a tropical environment

Determinaram-se os valores de temperatura do ar, umidade relativa e índice de temperatura e umidade (ITU) de uma propriedade rural de produção de leite a pasto e da estação meteorológica oficial mais próxima, confrontando-os. Na fazenda, as leituras dos dados foram registradas por uma estação meteorológica automática, a cada cinco minutos, de fevereiro de 2015 a setembro de 2016. Depois, calcularam-se a média por hora e o ITU horário. Selecionaram-se os valores diários mínimo, médio e máximo. O mesmo foi feito com os dados da estação meteorológica oficial, que foram horários. As temperaturas mínima e média na estação meteorológica foram maiores que na fazenda durante todo o período experimental e em 16 meses, respectivamente. A temperatura máxima da propriedade rural foi maior que a da estação em seis meses. Já a umidade relativa mínima, a média e a máxima da estação meteorológica foram inferiores às da fazenda. O ITU mínimo foi maior na estação oficial e o ITU máximo superior na fazenda em todos os meses. Por fim, o número de dias com um ITU máximo igual ou superior ao ITU crítico foi maior na fazenda. Assim, dados da estação meteorológica oficial subestimam o estresse por calor.(AU)

The values of air temperature, relative humidity and Temperature Humidity Index (THI) of one pasture-based milk production farm and from the nearest official weather station were confronted. At the farm, data readings were recorded by an automatic weather station, every five minutes, from February 2015 to September 2016. Then, the hourly average and hourly THI were calculated. The minimum, average, and maximum daily values were selected. The same was done with data from the official hourly weather station data. The minimum and mean temperature in the meteorological station were higher than on the farm throughout the experimental period and in 16 months, respectively. The maximum temperature of the rural property was greater than that of the station in six months. Meanwhile, the minimum, average, and maximum relative humidity of the meteorological station were lower than those of the farm. The minimum THI was higher at the official station and the maximum THI was higher at the farm in every month. Finally, the number of days with a maximum THI equal to or greater than the critical THI was greater on the farm. Thus, official weather station data underestimate the heat stress.(AU)

Efeito de dois sistemas de resfriamento sobre os hormônios tireoidianos e as variáveis termofisiológicas de matrizes suínas em lactação / Effect of two cooling systems on thyroid hormones and thermophysiological variables of lactating sows

Avaliaram-se os efeitos do sistema de resfriamento evaporativo com pressão negativa (SRE) e aspersão de água sobre o telhado (AAT), as variáveis termofisiológicas, os hormônios tireoidianos e a relação neutrófilo:linfócito (N:L) em porcas. Utilizaram-se 61 fêmeas em lactação, que foram divididas nos dois ambientes térmicos, sendo 30 em SRE e 31 em AAT, no verão. A temperatura e a umidade do ar, a frequência respiratória (FR), as temperaturas de superfície (TS) e retal (TR), a concentração de tiroxina e de tri-iodotironina, o número de neutrófilos e linfócitos e a relação N:L foram determinados. A temperatura ambiente pela manhã foi menor em SRE que em AAT (22,1ºC vs. 23,5ºC) e pela tarde (24,8ºC vs. 28,0ºC). Em ambos os períodos, a FR, a TS e a TR foram menores em SRE (de manhã 49 resp.min-1, 31,1ºC e 38,5ºC, respectivamente, e à tarde 55 resp.min-1, 30,3ºC e 38,8ºC, respectivamente) que em AAT (de manhã 54 resp.min-1, 32,8ºC e 38,6ºC, respectivamente; e à tarde 65 resp.min-1, 31,4ºC e 39,1ºC, respectivamente). Animais sob galpão AAT apresentaram menores concentrações de T4 que animais sob SRE (37,84 vs. 42,22nmol.L-1). Em ambiente tropical, no verão, porcas lactantes de ambos os sistemas mantêm a homeotermia.(AU)

The effects of the evaporative cooling system with negative pressure (ECS) and water spray on the roof (WSR) on physiological variables, thyroid hormones and neutrophil/lymphocyte ratio (N:L) in lactating sows were evaluated. Sixty-one lactating females were divided in the two thermal environments, being 30 in SRE and 31 in the AAT shed in the summer. The air temperature and humidity, respiratory frequency (RF), surface temperatures (ST) and rectal (RT), serum thyroxine and triiodothyronine concentration, number of neutrophils and lymphocytes and the N/L ratio were determined. In the afternoon, the matrices in ECS (Tar: 25.0°C and THI: 74.7) and WSR (Tar: 27.6°C and THI: 77.3) were exposed to heat stress. In the morning, RF, ST and RT were lower in ECS (49 breaths.min -1 , 31.1°C and 38.5°C, respectively) than WSR (54 breaths.min -1 , 32.8°C and 38.6°C) and also in the afternoon ECS (55 breaths.min -1 , 30.3°C and 38.8°C, respectively) and WSR (65 breaths.min -1 , 31.4°C and 39.1°C, respectively). Animals under WSR shed presented lower concentrations of T4 than animals under ECS (37.84 vs 42.22nmol.L -1 ). In a tropical environment, in the summer, lactating sows of both systems maintain homeothermia.(AU)

Efeito de diferentes tempos de exposição ao calor e de linhagens sobre o rendimento de carcaça e a composição química de peito de frangos de corte / Effect of different timing of exposure to heat and strains on the carcass yield and breast chemical composition of broiler

Investigaram-se os efeitos de diferentes tempos de exposição ao calor sobre o rendimento de carcaça, cortes e vísceras comestíveis e a composição química da carne de peito de frangos de corte de duas linhagens. Foram alojados 560 pintos de corte da linhagem Cobb 500 Slow® e 560 da Hubbard Flex® em 32 boxes. A partir do 14º dia, eles foram divididos nos ambientes térmicos: controle, uma hora, duas horas ou três horas diárias de estresse por calor. O rendimento de carcaça, peito sem osso, coxa e sobrecoxa com osso, asas, pés, fígado, moela e coração foi avaliado em seis aves de cada linhagem em cada ambiente térmico. Amostras foram obtidas para analisar matéria seca, extrato etéreo, proteína bruta e matéria mineral. O estresse cíclico por calor por até três horas diárias não influenciou o rendimento de carcaça, de peito sem osso, de coxa e sobrecoxa, de asa, de coração, de moela, de fígado e a composição química do peito. A linhagem Cobb 500 Slow® apresentou maior rendimento de peito. A Hubbard Flex® apresentou peito com maior percentual de matéria mineral e proteína. A linhagem Cobb é mais indicada à produção de peito, e a linhagem Hubbard à produção de frango inteiro.(AU)

The effects of different exposure periods under heat on the carcass yield, cuts and edible organs and breast chemical composition of broilers from two strains were investigated. Five hundred and sixty Cobb 500 Slow® and 560 Hubbard Flex® broiler chicks were housed in 32 pens and from the 14th day on, they were divided in thermal environments: control, 1 hour, 2 hours or 3 hours a day under heat stress. Carcass yield, boneless breast, thigh and drumstick with bone, wings, feet, liver, gizzard and heart were evaluated in six birds of each strain in each thermal environment. Samples were obtained to assess dry matter, ether extract, crude protein and mineral matter. The cyclic heat stress for up to three hours a day did not influence 33 the carcass yield, boneless breast, thigh and drumstick, wing, heart, gizzard, liver, and the breast chemical composition. Cobb 500 Slow® strain had higher breast yield. Hubbard Flex® had breast with higher percentage of mineral matter and protein. Cobb strain is best designed to breast production, and Hubbard is best for whole chicken production.(AU)

Calcium nitrate addition to control the internal load of phosphorus from sediments of a tropical eutrophic reservoir: microcosm experiments.

The main objective of this study was to perform laboratory experiments on calcium nitrate addition to sediments of a tropical eutrophic urban reservoir (Ibirité reservoir, SE Brazil) to immobilize the reactive soluble phosphorus (RSP) and to evaluate possible geochemical changes and toxic effects caused by this treatment. Reductions of 75 and 89% in the concentration of RSP were observed in the water column and interstitial water, respectively, after 145 days of nitrate addition. The nitrate application increased the rate of autotrophic denitrification, causing a consumption of 98% of the added nitrate and oxidation of 99% of the acid volatile sulfide. As a consequence, there were increases in the sulfate and iron (II) concentrations in the sediment interstitial water and water column, as well as changes in the copper speciation in the sediments. Toxicity tests initially indicated that the high concentrations of nitrate and nitrite in the sediment interstitial water (up to 2300 mg L(-1) and 260 mg L(-1), respectively) were the major cause of mortality of Ceriodaphnia silvestrii and Chironomus xanthus. However, at the end of the experiment, the sediment toxicity was completely removed and a reduction in the 48 h-EC50 of the water was also observed. Based on these results we can say that calcium nitrate treatment proved to be a valuable tool in remediation of eutrophic aquatic ecosystems leading to conditions that can support a great diversity of organisms after a restoration period.

Development of site-specific sediment quality guidelines for North and South Atlantic littoral zones: comparison against national and international sediment quality benchmarks.

We aimed to develop site-specific sediment quality guidelines (SQGs) for two estuarine and port zones in Southeastern Brazil (Santos Estuarine System and Paranaguá Estuarine System) and three in Southern Spain (Ría of Huelva, Bay of Cádiz, and Bay of Algeciras), and compare these values against national and traditionally used international benchmark values. Site-specific SQGs were derived based on sediment physical-chemical, toxicological, and benthic community data integrated through multivariate analysis. This technique allowed the identification of chemicals of concern and the establishment of effects range correlatively to individual concentrations of contaminants for each site of study. The results revealed that sediments from Santos channel, as well as inner portions of the SES, are considered highly polluted (exceeding SQGs-high) by metals, PAHs and PCBs. High pollution by PAHs and some metals was found in São Vicente channel. In PES, sediments from inner portions (proximities of the Ponta do Félix port's terminal and the Port of Paranaguá) are highly polluted by metals and PAHs, including one zone inside the limits of an environmental protection area. In Gulf of Cádiz, SQGs exceedences were found in Ria of Huelva (all analysed metals and PAHs), in the surroundings of the Port of Cádiz (Bay of Cádiz) (metals), and in Bay of Algeciras (Ni and PAHs). The site-specific SQGs derived in this study are more restricted than national SQGs applied in Brazil and Spain, as well as international guidelines. This finding confirms the importance of the development of site-specific SQGs to support the characterisation of sediments and dredged material. The use of the same methodology to derive SQGs in Brazilian and Spanish port zones confirmed the applicability of this technique with an international scope and provided a harmonised methodology for site-specific SQGs derivation.

Morfometria da mucosa duodenal em frangos de corte submetidos à temperatura ambiente cíclica elevada / Intestinal morphometry of the duodenal mucosa in broiler chickens underwent to high cyclic environment temperature

Os efeitos da temperatura ambiente cíclica elevada sobre a morfometria da mucosa duodenal e o peso corporal em frangos de corte foram avaliados. Setenta pintos de corte, machos, foram alojados em gaiolas e distribuídos em dois grupos. Um grupo foi submetido diariamente, durante uma hora, à temperatura ambiente cíclica elevada do primeiro até o 42º dia de idade (ambiente ST); e outro foi mantido em conforto térmico (ambiente TN). Cinco frangos de cada grupo foram sacrificados, semanalmente, por deslocamento cervical para mensuração da altura de vilosidades (VI), profundidade das criptas (CR) e relação vilo/cripta (VI/CR) duodenal. Dez aves de cada grupo foram pesadas semanalmente em balança digital. Utilizou-se delineamento inteiramente ao acaso em esquema fatorial 7x2 (sete idades: um, sete, 14, 21, 28, 35 e 42 dias, e dois ambientes: ST e TN). Os ambientes foram comparados pelo teste de Fisher (P<0,05), e, para avaliar o efeito da idade, foi realizada análise de regressão polinomial. As aves do ambiente ST apresentaram menores VI aos 14 e 21 dias, menor CR aos 28 dias e menor VI/CR aos 21 dias de idade do que as aves do ambiente TN. A temperatura ambiente cíclica elevada teve efeito danoso sobre a estrutura da mucosa duodenal de frangos de corte até a quarta semana de idade e sobre o peso corporal ao final do ciclo produtivo.

The effects of high cyclic environment temperature on body weight and morphometry of the duodenal mucosa in broiler chicken were evaluated. Seventy one-day-old male broiler chicks were sheltered in cages and distributed in two groups. One group was daily exposed to high cyclic environment temperature for an hour, from hatching to 42 days of age (group ST), the other one was kept under thermoneutral conditions (group TN). Five chickens of each group were weekly slaughtered by cervical delocation to mesure the villosities height (VI), crypts depth (CR), and villo/crypt ratio (VI/ CR) in the duodenum. Ten chickens of each group were weighted weekly on a digital balance. A completely randomized experimental design in a 7x2 factorial arrangement (hatching, seven, 14, 21, 28, 35, and 42 days of age and two environments: ST and TN). The environments were compared by Fisher test (P<0.05) and the effects of days of life by polynomial regression. The ST group had reduction in VI at 14 and 21 days of age (P<0.01), CR at 28 days of age (P<0.05), and in VI/CR at 21 days of age (P<0.01). Cyclic high environment temperature had harmful effect on intestinal structure of broiler from hatching to four weeks of age and on body weigh at the end of the productive cycle.