Seawater carbonate chemistry, Mg/Ca, Sr/Ca, oxygen production and calcification rate during experiments with coral Pocillopora damicornis, 2011

The Sr/Ca of aragonitic coral skeletons is a commonly used palaeothermometer. However skeletal Sr/Ca is typically dominated by weekly-monthly oscillations which do not reflect temperature or seawater composition and the origins of which are currently unknown. To test the impact of transcellular Ca2+ transport processes on skeletal Sr/Ca, colonies of the branching coral, Pocillopora damicornis, were cultured in the presence of inhibitors of Ca-ATPase (ruthenium red) and Ca channels (verapamil hydrochloride). The photosynthesis, respiration and calcification rates of the colonies were monitored throughout the experiment. The skeleton deposited in the presence of the inhibitors was identified (by 42Ca spike) and analysed for Sr/Ca and Mg/Ca by secondary ion mass spectrometry. The Sr/Ca of the aragonite deposited in the presence of either of the inhibitors was not significantly different from that of the solvent (dimethyl sulfoxide) control, although the coral calcification rate was reduced by up to 66% and 73% in the ruthenium red and verapamil treatments, respectively. The typical precision (95% confidence limits) of mean Sr/Ca determinations within any treatment was <±1% and differences in skeletal Sr/Ca between treatments were correspondingly small. Either Ca-ATPase and Ca channels transport Sr2+ and Ca2+ in virtually the same ratio in which they are present in seawater or transcellular processes contribute little Ca2+ to the skeleton and most Ca is derived from seawater transported directly to the calcification site. Variations in the activities of Ca-ATPase and Ca-channels are not responsible for the weekly-monthly Sr/Ca oscillations observed in skeletal chronologies, assuming that the specificities of Ca transcellular transport processes are similar between coral genera.

Apport d'un programme de génétique à une filière de production aquacole : l'exemple de l'ostréiculture

Two oyster species are currently present along the French coasts : the indigenous European flat oyster (Ostrea edulis), and the Pacific cupped oyster (Crassostrea gigas), that has been introduced from Japan since the beginning of the 70ies. The flat oyster successively suffered from two protozoan diseases during the 60ies and its production decreased from 20 000 tons/year by that time to 1 500 tons/year nowadays. Consequently, the oyster production is principally (99%) based upon the Pacific oyster species with approximately 150 000 tons/year among which 90% are grown from the natural spat. However, the hatchery production of this species is developing and was estimated to 400 to 800 millions spat in 2002. Moreover, strengthened relationships between IFREMER and the 5 commercial hatcheries, that all joined the SYSAAF (Union of the French poultry, shellfish and fish farming selectors), allow to plan for new genetic breeding programs. At the end of the 80ies, IFREMER initiated a genetic breeding program for the resistance of the European flat oyster to the bonamiosis, and obtained strains more tolerant to this disease. After two generations of massal selection, molecular markers had identified a reduced genetic basis in this program. It was then reoriented to an intra-familial selection. However, we were confronted to a zootechnic problem to manage such a scheme and we compromised by an intra-cohorts of families selection scheme managed using molecular markers. The program has now reached the transfer level with experimentation at a professional scale. Concerning the Pacific cupped oyster, and in parallel with the obtaining and the study of polyploids, performance of different Asian cupped oyster strains were compared to the one introduced in France thirty years ago and currently suffering from summer mortalities. The local strain exhibited better performance, certainly based upon a good local adaptation. In other respects, although early growth is a relevant criteria for selection for growth to commercial stage, it is not to be privileged in the context of an oyster producing region with a limited food availability. Contrary, the spat summer mortality became a priority for numerous teams (genetic, physiology, pathology, ecology,...) joined in the MOREST program. The first results showed important survival differences between fullsib and halsib families. They indicate a genetic determinism to this character "survival" and promote for its selection.

Estudo da prevalência e da gravidade da dermatite de contacto em 'frango do campo'

O sector avícola enfrenta atualmente dois desafios muito estimulantes. O primeiro decorre do aumento, que se prevê continuar a crescer, nos níveis de procura de carne de aves no mercado interno e internacional; o segundo decorre do facto da criação avícola ter adotado métodos de produção mais intensivos (kg peso vivo/m2/ano) e em maior escala, i.e. com maior concentração animal na mesma exploração. Este carácter vincadamente “industrial” tem merecido uma natural atenção das sociedades e das autoridades pecuárias no sentido desta economia de escala passar a ter num conjunto de instrumentos legais e técnicos o devido contrapeso para a salvaguarda das aves enquanto ser vivo. O presente trabalho tem como ponto de partida a Directiva 2007/43/CE do Conselho de 28 de Junho, relativa ao estabelecimento de regras mínimas para a proteção de frangos de carne. Em virtude de não existir ainda informação suficiente sobre a forma como a qualidade do maneio animal pode ser monitorizada, ao nível do abate, por médicos veterinários e auxiliares oficiais, em frangos de criação especial segundo os modelos definidos no Regulamento (CE) n.º 543/2008, urge realizar estudos neste domínio. O principal objetivo da realização do presente trabalho de campo foi o estudo da ocorrência das dermatites de contacto plantar (pododermatites) e da bolsa sinovial préesternal em frangos produzidos em sistemas de produção considerados “protetores” do bem-estar animal, designadamente os seguintes: i) ar livre; e, ii) extensivo de interior. O estudo foi efetuado num centro de abate de frangos do campo, em Oliveira de Frades, entre Maio de 20012 e Março de 2013. Os animais abatidos foram criados em explorações com contratos de integração situadas no Distrito de Viseu. Os dados foram recolhidos em 39 bandos diferentes da espécie Gallus domesticus, dos quais 1021 carcaças foram avaliadas após evisceração, o que correspondeu ao exame de uma a cada quinze aves da linha de abate. Para a avaliação da pododermatite foi utilizado o método adaptado pela DGAV, enquanto para a avaliação da bursite esternal foi efetuada tendo em conta o modelo aplicado em perus por Berk em 2002. Apesar do modelo estatístico desenvolvido para a análise dos resultados obtidos no presente trabalho exigir um maior número de observações, foi possível identificar com grande precisão alguns fatores de risco que devem ser realçados pela sua relevância no contexto dos sistemas produtivos escrutinados ou no mecanismo fisiopatológico da dermatite de contacto, nomeadamente os seguintes: (i) a idade das aves que, apesar de não ter sido identificada uma relação directa com os scores de pododermatite e bursite, verificou-se que a idade elevada que os animais tipicamente atingem nos sistemas de produção extensivos está associada a uma taxa superior de rejeições pela inspecção sanitária; (ii) o peso pré-abate que, independentemente da inconsistência defendida por diversos autores em relação à influência do peso vivo do frango industrial sobre a dermatite de contacto, nos animais produzidos em regime extensivo, esta variável pode desempenhar um fator chave para a ocorrência desta lesão. De facto, há que realçar que o peso destes animais tem uma importância fulcral na modelação da biomecânica da ave, incluindo na pressão exercida sobre a superfície plantar; (iii) o tipo de sistema de abeberamento, tendo ficado demonstrado que a selecção do tipo de bebedouro tem uma importância peculiar sobre a ocorrência de pododermatite em “frango de campo”, algo que está provavelmente relacionado com a influência exercida sobre o teor de humidade da cama. Globalmente, as frequências de pododermatite e bursite apuradas neste trabalho devem ser consideradas inquietantes. Esta preocupação eleva-se quando se toma consciência que as aves provieram de regimes considerados “amigáveis” e “sustentáveis”, pelo que urge monitorizar adequadamente aqueles sistemas produtivos, melhorar as suas condições e reanalisar os benefícios ao nível do bem-estar animal.

Effect of poultry viscera meal inclusion in broiler diets in different rearing periods on performance, carcass and parts yields

The objective of the present study was to evaluate the effect of the dietary inclusion of poultry viscera meal (VM) on broiler performance and carcass, parts, and abdominal fat yields in broilers by replacing a diet containing VM with a strictly vegetable diet and vice-versa. A number of 720 one-day-old broiler chicks were randomly distributed in 6 groups: G1-basal diet (BD) - corn and soybean based meal, with no VM from 1 to 42 days of age, G2- 8% VM diet from 1 to 42 days, G3- BD from 1 to 21 and 8% VM diet from 22 to 42 days, G4- BD from 1 to 35 and 8% VM diet from 36 to 42 days, G5- 8% VM diet from 1 to 21 days and BD from 22 to 42 days, G6- 8% VM diet from 1 to 35 and BD from 36 to 42 days. Average body weight, weight gain, feed intake, feed conversion ratio (FCR), production efficiency index, and mortality were determined from 1 to 42 days. There was no effect of treatments on performance or mortality, except for FCR, which was significantly better in the group fed VM from 1 to 35 days and withdrawn at the end of rearing (36-42 days). Also, there were no differences in carcass, parts, and abdominal fat yields, showing that VM in broiler diets does not influence yield parameters.

NITROUS OXIDE EMISSIONS IN COVER CROP-BASED CORN PRODUCTION SYSTEMS

Nitrous oxide (N2O) is a potent greenhouse gas; the majority of N2O emissions are the result of agricultural management, particularly the application of N fertilizers to soils. The relationship of N2O emissions to varying sources of N (manures, mineral fertilizers, and cover crops) has not been well-evaluated. Here we discussed a novel methodology for estimating precipitation-induced pulses of N2O using flux measurements; results indicated that short-term intensive time-series sampling methods can adequately describe the magnitude of these pulses. We also evaluated the annual N2O emissions from corn-cover crop (Zea mays; cereal rye [Secale cereale], hairy vetch [Vicia villosa], or biculture) production systems when fertilized with multiple rates of subsurface banded poultry litter, as compared with tillage incorporation or mineral fertilizer. N2O emissions increased exponentially with total N rate; tillage decreased emissions following cover crops with legume components, while the effect of mineral fertilizer was mixed across cover crops.

Method of numerical correction of errors occasioned by delay of records during the monitoring of environmental variables of interest for animal production

As condições de ambiente térmico e aéreo, no interior de instalações para animais, alteram-se durante o dia, devido à influência do ambiente externo. Para que análises estatísticas e geoestatísticas sejam representativas, uma grande quantidade de pontos distribuídos espacialmente na área da instalação deve ser monitorada. Este trabalho propõe que a variação no tempo das variáveis ambientais de interesse para a produção animal, monitoradas no interior de instalações para animais, pode ser modelada com precisão a partir de registros discretos no tempo. O objetivo deste trabalho foi desenvolver um método numérico para corrigir as variações temporais dessas variáveis ambientais, transformando os dados para que tais observações independam do tempo gasto durante a aferição. O método proposto aproximou os valores registrados com retardos de tempo aos esperados no exato momento de interesse, caso os dados fossem medidos simultaneamente neste momento em todos os pontos distribuídos espacialmente. O modelo de correção numérica para variáveis ambientais foi validado para o parâmetro ambiental temperatura do ar, sendo que os valores corrigidos pelo método não diferiram pelo teste Tukey, a 5% de probabilidade dos valores reais registrados por meio de dataloggers.

Characterization of heat waves affecting mortality rates of broilers between 29 days and market age

Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM) of birds between 29 and 31 days of age. Maximum temperature humidity index (THI) above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1) maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2) maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days.