Five million years of Antarctic Circumpolar Current strength variability.

The Antarctic Circumpolar Current (ACC) represents the world's largest ocean-current system and affects global ocean circulation, climate and Antarctic ice-sheet stability1-3. Today, ACC dynamics are controlled by atmospheric forcing, oceanic density gradients and eddy activity4. Whereas palaeoceanographic reconstructions exhibit regional heterogeneity in ACC position and strength over Pleistocene glacial-interglacial cycles5-8, the long-term evolution of the ACC is poorly known. Here we document changes in ACC strength from sediment cores in the Pacific Southern Ocean. We find no linear long-term trend in ACC flow since 5.3 million years ago (Ma), in contrast to global cooling9 and increasing global ice volume10. Instead, we observe a reversal on a million-year timescale, from increasing ACC strength during Pliocene global cooling to a subsequent decrease with further Early Pleistocene cooling. This shift in the ACC regime coincided with a Southern Ocean reconfiguration that altered the sensitivity of the ACC to atmospheric and oceanic forcings11-13. We find ACC strength changes to be closely linked to 400,000-year eccentricity cycles, probably originating from modulation of precessional changes in the South Pacific jet stream linked to tropical Pacific temperature variability14. A persistent link between weaker ACC flow, equatorward-shifted opal deposition and reduced atmospheric CO2 during glacial periods first emerged during the Mid-Pleistocene Transition (MPT). The strongest ACC flow occurred during warmer-than-present intervals of the Plio-Pleistocene, providing evidence of potentially increasing ACC flow with future climate warming.

Effects of cottonseed hull on intake, digestibility, nitrogen balance, blood metabolites and ingestive behaviour of rams.

The aim of this study was to determine the effect of cottonseed hull (CH) in the diets of rams on intake, digestibility, nitrogen balance, ingestive behaviour, and blood metabolites. Twenty males, uncastrated with an average body weight of 29.08 ± 4.18 kg, were distributed in a completely randomized design with four treatment diets and five replicates. The diet contained a forage to concentrate ratio of 50 : 50 (ground corn, soybean meal, corn silage, and CH), and the experimental treatments were inclusion of 0, 10, 20, and 30% CH (dry matter basis). Inclusion of CH linearly increased water intake, effective intake of ethereal extract and non-fibrous carbohydrates, and crude protein digestibility. Dry matter (DM) and neutral detergent fiber (NDF) digestibility, nitrogen faecal losses, and nitrogen balance reduced linearly with CH inclusion in the diet. Inclusion of CH in rams' diet reduces intake, nutrient digestibility, and intake and rumination efficiencies. Thus, it is not recommended to add this by-product to the diet of high-performance rams, but for nurture that does not aim at high performance, inclusion of up to 5% of this by-product is recommended.

Intake and digestibility in sheep fed on marandu grass silages added with dehydrated barley / Ingestão e digestibilidade de ovinos alimentados com silagens de capim-marandu aditivadas com resíduo de cervejaria desidratado

The objective was to evaluate the intake and the apparent digestibility in sheep fed on marandu grass silages added with dehydrated barley. Twenty crossbred Santa Inês lambs were used, with a mean initial weight of 30±4.5 kg and mean age of 14±2 months. The experimental sheep were distributed into a completely randomized design and lining, with five treatments and four repetitions, with treatments levels of inclusion of 0, 10, 20, 30 and 40% natural matter of naturally dehydrated brewery residue for 36 hours to the marandu grass silage to feed the sheep. The evaluation period lasted 21 days, 15 for adaptation to the diets and 7 days for data collection. The data was submitted to analysis of variance, and when significant (P<0.05) the treatment means were analysed by regression. The inclusion of dehydrated barley to silage showed a linear increase in water intake (P<0.05), increased by 0.02% per unit of dehydrated barley. A quadratic effect was observed for the levels of dehydrated barley on the dry matter intake (DM), estimating a maximum consumption of 2.86% DM for silages containing 17.8% dehydrated barley. The crude protein intake (CP) behaved quadratically, with the maximum value estimated of 0.29% CP at a level of 22.5% dehydrated barley. Ether extract (EE) intake also exhibited quadratic behaviour (P<0.05), with the maximum value estimated of 0.2% EE at a level of 28.25% dehydrated barley. The regression study showed quadratic behaviour; with the maximum estimated value of neutral detergent fibre was 2.33% at a level of 34.58% dehydrated barley. No statistical significance was found for the intake of acid detergent fibre or organic matter (P>0.05). It was concluded that the addition of levels of 20 to 30% of dehydrated barley to silage resulted in a positive response for the dry matter intake, crude protein, Ether extract and neutral detergent fibre.(AU)

Objetivou-se avaliar o consumo e a digestibilidade aparente de ovinos alimentados com silagens de capim marandu aditivadas com resíduo de cervejaria desidratado. Foram utilizados 20 ovinos mestiços de Santa Inês machos inteiros, com peso médio inicial de 30±4.5 kg e média de 14±2meses de idade. O delineamento experimental foi o inteiramente casualizado, com cinco tratamentos e quatro repetições, sendo os tratamentos níveis de inclusão de 0, 10, 20, 30 e 40% da matéria natural de resíduo de cervejaria desidratado naturalmente por 36 horas à silagem de capim-marandu. O período de avaliação teve duração de 21 dias, sendo 15 para adaptação às dietas e seis para as coletas. Os dados foram submetidas à análise de variância, e quando significativo, as médias dos tratamentos à análise de regressão. A inclusão do resíduo de cervejaria desidratado promoveu aumento linear (P<0,05) no consumo de água, que aumentou em 0,02 ponto percentual a cada unidade de resíduo adicionada. Observou-se efeito quadrático (P<0,05) nos níveis de resíduo de cervejaria desidratado sobre o consumo de matéria seca, estimando-se consumo máximo de 2,86% peso vivo (PV) para silagens contendo 17,8% de resíduo de cervejaria. O consumo de proteína bruta apresentou comportamento quadrático, de modo que o valor máximo foi estimado em 0,29%PV de proteína bruta para o nível de 22,5% de resíduo de cervejaria desidratado. Para o consumo de extrato etéreo, houve comportamento quadrático (P<0,05), em que o valor máximo foi estimado em 0,2%PV de extrato etéreo para o nível de 28,25% de resíduo de cervejaria desidratado. O estudo de regressão mostrou comportamento quadrático (P<0,05) para o consumo de fibra em detergente neutro, em que o valor máximo foi estimado em 2,33% PV de fibra em detergente neutro para o nível de 34,58% de resíduo de cervejaria desidratado. Para os consumos de fibra em detergente ácido e matéria orgânica, não foi observada significância estatística (P>0,05). Conclui-se que silagens aditivada com níveis de 20 a 30% de resíduo de cervejaria desidratado, promoveram respostas positivas aos consumos de matéria seca, proteína bruta, extrato etéreo e fibra em detergente neutro.(AU)

Unlimited access to low-energy diet causes acute malnutrition in dams and alters biometric and biochemical parameters in offspring.

Here we analyze the outcomes of unlimited access to a low-energy (LE) diet in dams and their offspring. At 3 weeks' gestation, pregnant Wistar rats were divided into two groups: (1) the control group received a normoenergetic diet; and (2) the experimental group received the LE diet. In dams, lactation outcomes, food intake, body weight, plasma IGF-1, prealbumin, transferrin and retinol-binding protein levels were evaluated; in offspring, biometric and biochemical parameters and food intake were evaluated. No differences were observed during pregnancy. However, after lactation, dams that received the LE diet demonstrated significant reductions in body weight (P<0.05), plasma IGF-1 (P=0.01), prealbumin and visceral fat (P<0.001). Pups born to dams that received the LE diet demonstrated reduced body length and weight at weaning (P<0.001) and were lighter than the control animals at the end of the experimental period. Pups also demonstrated reduced plasma, low-density lipoprotein (P=0.04), triglycerides (P=0.002) and glucose levels (P<0.05), and differences were noted in visceral fat. These results indicate that feeding dams with LE diet during the reproductive period induces acute malnutrition and impairs the growth and development of offspring, as well as certain metabolic parameters.

Biomonitoring method for the simultaneous determination of cadmium and lead in whole blood by electrothermal atomic absorption spectrometry for assessment of environmental exposure.

The aim of this work is to propose a biomonitoring method for the simultaneous determination of Cd and Pb in whole blood by simultaneous electrothermal atomic absorption spectrometry for assessment of environmental levels. A volume of 200 microL of whole blood was diluted in 500 microL of 0.2% (wv(-1)) Triton) X-100+2.0% (vv(-1)) HNO3. Trichloroacetic acid was added for protein precipitation and the supernatant analyzed. A mixture of 250 microg W+200 microg Rh as permanent and 2.0% (wv(-1)) NH4H2PO4 as co-injected modifiers were used. Characteristic masses and limits of detections (n=20, 3s) for Cd and Pb were 1.26 and 33 pg and 0.026 microg L(-1) and 0.65 microg L(-1), respectively. Repeatability ranged from 1.8 to 6.8% for Cd and 1.2 to 1.7% for Pb. The trueness of method was checked by the analysis of three Reference Materials: Lyphocheck Whole Blood Metals Control level 1 and Seronorm Trace Elements in Whole Blood levels 1 and 2. The found concentrations presented no statistical differences at the 95% confidence level. Blood samples from 40 volunteers without occupational exposure were analyzed and the concentrations ranged from 0.13 to 0.71 microg L(-1) (0.32+/-0.19 microg L(-1)) for Cd and 9.3 to 56.7 microg L(-1) (25.1+/-10.8 microgL(-1)) for Pb.