Essential Oils in Nellore Beef Cattle: In Vivo Impact on Rumen Emissions.

Essential oils (EOs), as rumen additives, decreased CH4 emissions in in vitro trials but results from in vivo studies are still limited. We investigated the effects of Origanum vulgare (OEO) and Thymus vulgaris (TEO) EOs on in vivo methane emissions from Nellore beef cattle. Six adult rumen-cannulated Nellore cattle were used in a double 3 × 3 Latin square design. Treatments consisted of three diets containing either 3 mL OEO per kg of concentrate, 3 mL TEO/kg of concentrate, or no EO addition. The experimental period consisted of three 21 d feeding periods and methane production was measured using the sulfur hexafluoride (SF6) technique from Day 16 to Day 21 of each feeding period. Intake, total apparent digestibility (dry matter as well as neutral and acid detergent fiber), and rumen parameters (pH, ammoniacal nitrogen concentration, and short-chain fatty acids) were also evaluated. The EOs did not decrease CH4 emissions and had no effect on rumen parameters.

Effect of timing of paddock allocation in tropical grass on performance, nitrogen excretion, and enteric methane emissions from dairy cows.

The objective of this study was to investigate the influence of timing of paddock allocation (AM or PM) in tropical grass on nutritive value of the herbage, dry matter intake (DMI), milk yield and composition, ruminal fermentation, nitrogen excretion, and enteric CH4 emissions of dairy cows. Twenty cows were grouped in pairs and randomly distributed within pair to one of two treatments. PM herbage had greater contents of dry matter (DM), soluble carbohydrates, starch, and nonfibrous carbohydrate to protein ratio and lower contents of neutral detergent fiber and acid detergent fiber. There was no treatment effect on DMI, N excretion, milk yield, and CH4 emissions. However, milk protein and casein yields tended to be greater for PM than AM, while milk urea nitrogen concentration was lower for PM than AM. The increase in nutritive value of the afternoon relative to the morning herbage within the framework of this study was not large enough to increase DMI and milk yield or to decrease CH4 emission intensity by the dairy cows as hypothesized. The findings indicate that PM treatment can be a simple and useful grazing strategy that results in an herbage harvest with greater nutritional value and in lower excretion of urea N into milk.

Increased atmospheric CO2 combined with local climatic variation affects phenolics and spider mite populations in coffee trees.

Modelling studies on climate change predict continuous increases in atmospheric carbon dioxide concentration [CO2] and increase in temperature. This may alter carbon-based phytochemicals such phenolics and modify plant interactions with herbivorous. We investigated the effects of enhanced [CO2] and local climatic variation on young coffee plants, Coffea arabica L. cv Catuaí vermelho IAC-144 and Obatã vermelho IAC-1669-20, cultivated in the FACE (Free-Air Carbon Dioxide Enrichment) facility under two atmospheric [CO2] conditions. Coffee leaves were evaluated for total soluble phenolics (TSP), chlorogenic (5-CQA) and caffeic (CAF) acids, diversity and population size of mites, along two dry and two rainy seasons. Elevated atmospheric CO2 (e[CO2]) significantly decreased 5-CQA in cv. Catuaí but did not affect cv. Obatã. Species richness and population size of mites in coffee leaves were not affected by e[CO2] but were strongly related to the seasonal variability of coffee leaf phenolics. In general, high levels of phenolics were negatively correlated with population size while the mite species richness were negatively correlated with 5-CQA and TSP levels. Our findings show that [CO2] enhancement affects phenolics in coffee plants differentially by cultivars, however seasonality is the key determinant of phenolics composition, mite species richness and population size.

Effect of pasture management on enteric methane emissions from goats.

The effect of pasture management on CH4 emissions was investigated from goats in a tropical climate. Two experiments were conducted in a "Tanzania Guinea grass" (Panicum maximum Jacq.) pasture to assess enteric CH4 production in a completely randomized design. Emissions from light, moderate, and heavy grazing intensities were analyzed in the first experiment, and variations between grazing days were explored in the second experiment. Grazing intensity was defined as 2.4, 1.6, and 0.8 post-grazing leaf area index. Pasture management employed intermittent grazing with variable stocking rate using Anglo Nubian female adult goats. SF6 tracer gas technique was used to measure CH4 production. Grazing intensity was not found to affect CH4 emissions per animal, dry matter forage intake (DMI), and gross energy (GE) intake. However, the second experiment showed that CH4 production was influenced by the grazing day. CH4 emissions were 18.1 g day-1, and the variables were 0.88 g kg-1 of metabolic weight, 17.45 g kg-1 of DMI, and 5.5% of GE. CH4 production increased linearly with the grazing day, possibly reflecting a reduction in forage quality. These findings suggest that the day of occupation in intermittent grazing has a greater effect on CH4 emissions than that by grazing intensity and that a single day grazing of Tanzania Guinea grass could mitigate CH4 emissions.

Tannin as a natural rumen modifier to control methanogenesis in beef cattle in tropical systems: Friend or foe to biogas energy production?

The grazing of Zebu cattle in poor-quality tropical pastures during the dry season has an increased environmental impact and cost of production. The use of condensed tannins (CT) as a natural feed additive to modulate ruminal archaea can mitigate the methane emissions from cattle in tropical systems. We investigated the effects of CT on in vivo methane emissions and rumen microbiota ecology in beef cattle. Batch experiments were also conducted to evaluate the impact of dietary CT on the biogas production from beef cattle manure. Six adult rumen-cannulated Nellore cattle were used in a double 3 × 3 Latin square design. Treatments consisted of three diets containing either a 0%, 1.25% or 2.5% CT additive from Acacia mimosa extract. The experimental period consisted of 63 days, and methane production was measured using the sulfur hexafluoride (SF6) technique from Day 16 to 21 of each feeding period. Adding Acacia extract to the diets reduced daily methane emissions per animal. Methane suppression occurred more by reduction of intake than by the direct effect on methanogenic archaea. We verified that CT directly suppresses archaea rumen communities and increases total rumen bacteria. Our study indicates that CT benefit rumen Fibrobactersuccinogenes and Ruminoccous flavefaciens populations and have no negative effect on biogas production from cattle manure. Acacia extract as a feed additive has promising potential as part of an overall nutritional strategy to reduce the methanogenesis from Zebu beef cattle in tropical systems.

Methane emission from a flooded rice field under pre-germinated system / Emissão de metano em área de arroz irrigado sob sistema pré-germinado

ABSTRACT: Local greenhouse gas flow measurement studies have been encouraged at a global level as a subsidy for national and state inventories. This study aimed to evaluate the seasonal methane emission during the 2008/2009 harvest, from an irrigated rice plantation, under pre-germinated system, in the municipality of Tremembé, State of São Paulo, using the static chamber technique and gas chromatography. The study showed high seasonal emission of methane (CH4) for the studied area, probably due to the long flooding period. It was estimated the CH4 emission factor (6.51 kg CH4 ha-1 dia-1), the partial global warming potential (pGWP, 27.2 Mg CO2eq growing season-1 ha-1) and the yield-scaled pGWP (YpGWP, 3.9 kg CO2eq kg-1 grain).

RESUMO: Estudos locais de mensuração de fluxos de gases de efeito estufa em sistemas agrícolas têm sido incentivados a nível global como base para subsidiar estimativas nacionais e estaduais de emissão. Este estudo objetivou quantificar a emissão sazonal de metano (CH4) em cultivo de arroz irrigado, sob sistema pré-germinado, no município de Tremembé, Estado de São Paulo, na safra de 2008/2009, utilizando o método de câmara estática e cromatografia gasosa. O estudo mostrou elevada emissão sazonal de CH4 para a área estudada, em função, provavelmente do longo período de inundação. Foi estimado o fator de emissão de CH4 (6,51 kg CH4 ha-1 dia-1), o potencial de aquecimento global parcial (PAGp, 27,2 Mg CO2eq estação de crescimento-1 ha-1) e o PAGp escalonado pelo rendimento (R) de grãos (PAGpR, 3,9 kg CO2eq kg-1 grão).

Strategic grazing management towards sustainable intensification at tropical pasture-based dairy systems.

Agricultural systems are responsible for environmental impacts that can be mitigated through the adoption of more sustainable principles. Our objective was to investigate the influence of two pre-grazing targets (95% and maximum canopy light interception during pasture regrowth; LI95% and LIMax, respectively) on sward structure and herbage nutritive value of elephant grass cv. Cameroon, and dry matter intake (DMI), milk yield, stocking rate, enteric methane (CH4) emissions by Holstein × Jersey dairy cows. We hypothesized that grazing strategies modifying the sward structure of elephant grass (Pennisetum purpureum Schum.) improves nutritive value of herbage, increasing DMI and reducing intensity of enteric CH4 emissions, providing environmental and productivity benefits to tropical pasture-based dairy systems. Results indicated that pre-sward surface height was greater for LIMax (≈135 cm) than LI95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. Grazing management based on LI95% criteria improved herbage nutritive value and grazing efficiency, allowing greater DMI, milk yield and stocking rate by dairy cows. Daily enteric CH4 emission was not affected; however, cows grazing elephant grass at LI95% were more efficient and emitted 21% less CH4/kg of milk yield and 18% less CH4/kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH4 emissions per hectare in LI95% grazing management. Thereby the same resource allocation resulted in a 16% mitigation of the main greenhouse gas from pasture-based dairy systems. Overall, strategic grazing management is an environmental friendly practice that improves use efficiency of allocated resources through optimization of processes evolving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems.

E2 potentializes benzo(a)pyrene-induced hepatic cytochrome P450 enzyme activities in Nile tilapia at high concentrations.

In the aquatic environment, biotransformation enzymes are established biomarkers for assessing PAH exposure in fish, but little is known about the effect of 17ß-estradiol (E2) on these enzymes during exposure to benzo(a)pyrene (BaP). In this study, Nile tilapia (Oreochromis niloticus) were exposed for 3, 5, and 10 days to BaP (300 µg L(-1)) and E2 (5 µg L(-1)). These substances were applied isolated or mixed. In the mixture experiment, fish were analyzed pre- and postexposure in order to better understand whether preexposure to the hormone masks the responses activated by PAH or vice versa. Phase I enzymes ethoxyresorufin-O-deethylase (EROD), pentoxyresorufin-O-depenthylase (PROD), and benzyloxyresorufin-O-debenzylase (BROD) activities as well as the phase II enzyme glutathione S-transferase (GST) were analyzed. Isolated E2 treatment decreased EROD activity after 3 days, but this enzyme activity returned to control values after 5 and 10 days of exposure. Isolated BaP treatment significantly induced EROD activity after 3 and 5 days, and the activity returned to control levels after ten exposure days. Combined treatment (E2 + Bap) significantly increased EROD activity, both in the pre- and postexposure. This increase was even higher than in the isolated BaP treatment, suggesting a synergism between these two compounds. When E2 and BaP were used singly, they did not change BROD and PROD activities. However, combined treatment (E2 + Bap) significantly increased PROD activity. Isolated BaP treatment increased GST activity after 10 days. However, this response was not observed in the mixture treatment, suggesting that E2 suppressed the GST induction modulated by BaP. The results put together indicated that E2 altered the biotransformation pathway regarding enzymes activated by BaP in Nile tilapia.

Influence of different supplements and sugarcane (Saccharum officinarum L.) cultivars on intake, digestible variables and methane production of dairy heifers under tropical conditions.

The sulphur hexafluoride (SF(6)) gas tracer method was used to measure methane (CH(4)) production of crossbred (3/4 Holstein x Zebu) dairy heifers fed two types of sugarcane (Saccharum officinarum L.; cultivar IAC-862480 (CC1) or cultivar IAC-873184 (CC2)) and supplemented with urea or concentrate. The study was performed at Embrapa Southeast Cattle, São Carlos, SP, Brazil, using a completely randomised design. Differences between treatments were significant for digestibility of dry matter, organic matter and energy. When animals were supplemented with urea differences between sugarcane cultivars did occur for NDF consumption, but not for daily methane production. This suggest that variation in chemical composition of sugarcane did not affect bovine ruminal CH(4) emissions. Concentrate inclusion in animal diet increased digestible organic matter intake, improving the nutrient intake by animals, but did not reduce CH(4) production expressed as a percentage of gross energy intake.

Variação diária da emissão de metano em solo cultivado com arroz irrigado no Sul do Brasil / Diurnal variation of methane emission from a paddy field under rice cultivation in the Southern Brazil

O metano (CH4 ) apresenta um potencial de aquecimento 23 a 32 vezes maior do que o dióxido de C e a sua emissão diária em lavouras de arroz varia com a temperatura do solo e da água, e o metabolismo das plantas. O objetivo deste estudo foi determinar o horário apropriado à coleta de amostras de ar para quantificar a emissão média diária de CH4, informação fundamental para estudos visando a derivação de índices regionais de emissão desse gás. Três campanhas de monitoramento da emissão de CH4, com coletas em intervalos de 3h, foram realizadas nos estágios de emissão da panícula (campanha 1) e de maturação de grãos (campanhas 2 e 3) do arroz sob diferentes sistemas de cultivo (convencional e plantio direto) na safra 2002/2003, na Estação Experimental do Instituto Rio Grandense do Arroz, em Cachoeirinha, RS. A coleta das amostras de ar foi realizada com seringas de poliestireno em câmaras de alumínio de 1m², sendo que as análises de metano foram realizadas por cromatografia gasosa. A emissão diária de CH4 apresentou padrão similar nas três campanhas de amostragem independente do sistema de cultivo. A faixa de emissão mínima (4-19mg CH4m-2 h-1) ocorreu entre as 24 horas e o início da manhã seguinte (9 horas), e a faixa de emissão máxima (8-33mg CH4 m-2 h-1) do início à metade da tarde (12-15 horas). A emissão de CH4 foi relacionada à temperatura da água de inundação (campanhas 1 e 3) e do solo (campanha 2). Com base nas curvas de emissão diária e considerando aspectos operacionais como a viabilidade de análise cromatográfica das amostras no período de 24h após a coleta, o intervalo entre 9 e 12 horas é recomendado para a avaliação das emissões de CH4 em lavouras de arroz irrigado quando objetiva-se a obtenção de valores equivalentes à emissão média diária desse gás. Acredita-se que a alta relação entre a temperatura e a emissão de metano valida esse procedimento para as sub-regiões produtoras de arroz no Sul do Brasil (região litorânea e Sul...

Methane (CH4) has a global warming potential 23 to 32 times higher than carbon dioxide and its emission rate in rice fields should vary daily with water and soil temperature, and plant metabolism. This study aimed to identify the appropriate time interval for air sampling in order to quantify the mean daily CH4 emission rate, key information to future studies aiming the derivation of regional indexes of CH4 emission. Three campaigns were performed to evaluate diurnal variation in CH4 emissions (3h interval) from continuously flooded rice (Oryza sativa L. cv. 'IRGA-422 CL') fields at different crop stages (panicle differentiation and ripening) and management systems (conventional tillage-CT and no-tillage-NT) during 2002/2003 crop season in long-term experiment at the Instituto Rio Grandense do Arroz (IRGA), in Cachoeirinha, RS, Brazil. Static chamber method was used and the air samples collected with polystyrene syringes were analyzed by gas chromatography. Methane emission showed a same diurnal pattern in the three campaigns in the both tillage systems. The maximum range of emission (8-33mg CH4m-2 h-1) was observed in the early afternoon (12.00 to 15.00p.m.) followed by a decline to a minimum around midnight to next morning (4-19mg CH4 m-2 h-1), in which fluxes were related to flood water temperature (campaign 1 and 3) or soil temperature (campaign 2). Taking into account the daily emission curves, plus operational aspects like chromatographic analysis of samples into the 24h period after air sampling, the time interval from 9.00 to 12.00a.m. is recommended to studies aiming to evaluate mean daily CH4 emission in rice fields. The close relationship between temperature and methane emission allows us infer about the suitability of the gas sampling procedure for the different rice sub-regions of South of Brazil (littoral region and south of RS, and south of SC) that present the same daily behavior of solar radiation and air temperature...

Exsudato glandular de genótipos de tomateiro e desenvolvimento de Bemisia tabaci (Genn) (Sternorryncha: Aleyrodidae) biótipo B / Glandular exudate of tomato genotypes and development of Bemisia tabaci (Genn) (Sternorryncha: Aleyrodidae) biotype B

Bemisia tabaci (Genn.) é uma das principais pragas do tomateiro no Brasil, provocando severas perdas devido à sucção de seiva, indução do amadurecimento irregular dos frutos e transmissão de viroses. O objetivo deste trabalho foi determinar o efeito de tricomas glandulares no desenvolvimento de B. tabaci biótipo B em oito genótipos de tomateiro, em casa de vegetação. Utilizou-se o delineamento de blocos ao acaso, em arranjo fatorial (genótipo x exsudato), com três repetições, sendo os genótipos avaliados na condição com e sem exsudato. Adultos da mosca-branca foram transferidos para uma gaiola de voil, onde permaneceram durante 24h. As variáveis avaliadas foram número de ovos e viabilidade, período de incubação, número de ninfas, duração e sobrevivência da fase ninfal. Efetuou-se a contagem de tricomas e a determinação do pH e teor de acilglicose para todos os genótipos. Na presença de exsudato, LA716 proporcionou redução na oviposição do inseto, o que sugere efeito antixenótico. Resistência antixenótica em LA1739 e PI134417 não foi associada ao exsudato glandular. O efeito do exsudato na oviposição do inseto foi explicado pelo teor de acilglicose. O pH apresentou papel secundário na oviposição da mosca-branca. A densidade de tricomas favoreceu o desenvolvimento do inseto. LA1584 destacou-se pela redução na sobrevivência do inseto e prolongamento do ciclo, além de propiciar oviposição intermediária, podendo ser adequado para incorporação em programas de melhoramento. Entretanto, há necessidade de estudos adicionais para determinar o potencial de uso desse genótipo ou de seus híbridos no manejo integrado de pragas.

Bemisia tabaci (Genn.) is one of the most important tomato pests in Brazil and causes severe losses due to the sap suction, the induction of the irregular ripening of the fruit and virus transmission. The objective of this study was to determine the effect of exudates released by the glandular trichomes on the development of B. tabaci biotype B on eight tomato genotypes, under greenhouse conditions. The experiment was arranged as a factorial scheme (genotype x exudate) in a randomized block design, with three replications, being the genotypes evaluated in two conditions (with and without exudate). Whitefly adults were transferred to a voile cage for 24h. The variables evaluated were number of eggs and viability, incubation period, number of nymphs, duration and viability of the nymphal stage. Trichome counts and determination of pH and acylglucose content were made for all the genotypes. Intact leaflets of LA716 were less accepted for oviposition than leaflets without exudate, which suggests an antixenotic effect. Antixenotic resistance in LA1739 and PI134417 was not associated to the glandular exudate. The effect of exudates on the insect oviposition was explained by the acylglucose content. The pH showed secondary role on the whitefly oviposition. Trichomes density improved the insect development. LA1584 reduced the insect survival and increased its cycle, besides promoting an intermediate oviposition. For this reason, it can be useful in breeding programs. However, further studies are needed to determine the potential of this genotype and hybrids for future utilization in integrated pest management.