Growth hormone and prolactin secretion in growing domestic fowl: Influence of sex and breed

1. Plasma growth hormone (GH) and prolactin concentrations were measured between 1 and 24 weeks of age in both sexes of a laying strain of chickens and from 1 to 9 weeks of age in broiler cockerels.

2. GH and prolactin concentrations were highest in young birds and higher in males than in females.

3. In both sexes GH and prolactin concentrations were correlated inversely with age and body weight and positively with relative weight gain.

4. Differences in growth rate between broilers and layers were related to differences in blood GH concentrations.

5. Water deprivation for periods of 6, 12, 18 or 24 h increased plasma prolactin markedly but did not affect GH secretion significantly.     

Addressing ecological,economic, and social tradeoffs of refuge expansion in constrained landscapes

Landscape Ecology - Conservation planning increasingly needs to be effective in areas that are influenced by anthropogenic land uses, yet many planning tools do not give equal consideration to...     

Quantification of priming and CO2 emission sources following the application of different slurry particle size fractions to a grassland soil

The highest emissions of CO₂ from soils and most pronounced priming effect (PE) from soils generally occur immediately after slurry application. However, the influence of different particle size slurry fractions on net soil C respiration dynamics and PE has not been studied. Therefore, a slurry separation technique based on particle sizes was used in the present study. Six distinct fractions (>2000, 425-2000, 250-425, 150-250, 45-150, <45 μm) were generated from two dairy slurries (one from cows fed a predominantly maize silage diet and the other from cows fed a grass silage diet) were applied to soil. During the first days of the 332 days experiment, all slurry fraction amendments significantly increased soil CO₂ effluxes (by 2-8 times) compared to the non-amended control. The increased CO₂ emission rates had a negative relationship with slurry particle size, but its duration was positively correlated with slurry particle size. The percentage of the cumulative CO₂ emitted was only higher in the first 8 days in the finest slurry particle sizes (<150 μm). The proportion of slurry-derived C emitted as CO₂ 2 h after addition to soil varied between 29% and 100% of total emitted CO₂-C. Generally, the proportion of slurry-derived C emitted initially decreased rapidly in the <250 μm fractions, but decreased more slowly or even increased in the >250 μm fractions. The overall contribution of slurry C to total CO₂ emissions was higher in smaller slurry particle size treatments in the first days after application. The addition of the various slurry fractions to soil caused both significant positive and negative PEs on the soil organic matter mineralization. The timing and type (positive or negative) of PE depended on the slurry particle size. Clearly, farm based separation pre-treatment leading to two or more fractions with different particle sizes has also the potential to reduce or modify short-term CO₂ emissions immediately after slurry application to soil.     

Demonstration and validation of enhanced monitored natural recovery at a pesticide-contaminated sediment site

Purpose

Monitored natural recovery (MNR) combined with a thin-layer cap (TLC), often referred to as enhanced monitored natural recovery (EMNR), has the potential to accelerate and improve the effectiveness of MNR as a remedial strategy while minimizing widespread disturbance to the existing habitat. This study evaluated the effectiveness of a nominal 15-cm thin-layer sand cap as an EMNR remedial strategy to address sediments that were moderately contaminated with the chlorinated pesticide dichlorodiphenyltrichloroethane and its derivatives, collectively DDX.

Materials and methods

Physical, chemical, and biological measurements were conducted pre-remedy placement and 2, 14, and 25 months post-placement. Measurements were used to evaluate (1) TLC stability; (2) bottom-up mixing of the TLC; (3) advection through the TLC; (4) characteristics of newly deposited sediment atop the EMNR layer compared to pre-remedy surface sediment conditions; (5) changes in contaminant bioavailability; and (6) physical impacts to the benthic community.

Results and discussion

Significant reductions were observed from measurements conducted pre- and post-placement in surface sediment (84–97%), porewater (33–75%), and tissue concentrations (Lumbriculus variegatus deployed in situ) (72–82%). A 63 to 72% decrease in DDX depositional mass flux also was observed. Multiple lines of evidence indicated that the TLC material remained stable. Deposition of suspended material with low concentrations of DDX influenced low concentrations in the surface sediments. No adverse effects were observed on the benthic invertebrate community after TLC placement, and ecological metrics indicated increases in benthic community health, even in the short time period (2 months) following TLC placement.

Conclusions

This demonstration showed that EMNR can be effective at reducing biological exposure in surface sediments while minimizing short-term disturbances to benthic communities at sites where MNR is a remedy option, but natural deposition rates are inadequate to achieve cleanup goals within a reasonable timeframe.

     

Regulation of Anti‐Müllerian Hormone and Its Receptor Expression around Follicle Deviation in Cattle

The anti‐Müllerian hormone (AMH) is an important marker of ovarian reserve and for predicting the response to superovulatory treatments in several species. The objective of this study was to investigate whether AMH and its receptor (AMHR2) are regulated in bovine granulosa cells during follicular development. In the first experiment, granulosa cells were retrieved from the two largest follicles on days 2 (before), 3 (at the expected time) or 4 (after deviation) of follicular wave. In the second experiment, four doses of FSH (30, 30, 20 and 20 mg) or saline were administered twice a day starting on Day 2 of the first follicular wave of the cycle. Granulosa cells and follicular fluid were collected from the two largest follicles 12 h after the last injection of FSH or saline. AMH mRNA abundance was similar in granulosa cells of the two largest follicles (F1 and F2) before deviation (Day 2), but greater in dominant (DF) than subordinate follicles (SF) at the expected time (Day 3) and after (Day 4) deviation (p < 0.05). In experiment 1, AMH mRNA levels declined in both DF and SF near the expected time and after deviation when compared to before deviation. There was no difference in AMHR2 mRNA levels before and during follicular deviation (p > 0.05), but they tended to be greater in DFs than SFs (p < 0.1) after deviation. Experiment 2 showed that AMH and AMHR2 mRNA in granulosa cells and AMH protein abundance in follicular fluid were similar (p > 0.05) between both co‐dominant follicles collected from the FSH‐treated cows. These findings indicate the followings: AMH mRNA levels decrease in both DFs and SFs during follicular deviation; granulosa cells from heathy follicles express more AMH mRNA compared to subordinate follicles undergoing atresia and FSH stimulates AMH and AMHR2 mRNA expression in granulosa cells of co‐dominant follicles.     

Amur tigers and leopards returning to China: direct evidence and a landscape conservation plan

Context

The Amur tiger and leopard, once roaming over the Eurasian continent, are now endangered and confined to the Sikhote-Alin Mountains, Russia—a landscape that has been increasingly fragmented due to human activities. The ultimate fate of these big cats depends on whether they can resettle in their previous main historical range in NE China. Recent sightings of these animals along the China–Russia border have aroused new hope, but direct evidence is lacking.

Objectives

The main objectives of our study were (1) to determine the abundance and spatiotemporal patterns of tigers, leopards, and primary prey; (2) to investigate factors influencing the resettlement of the two big cats; and (3) to propose a landscape-scale conservation plan to secure the long-term sustainability of the Amur tiger and leopard.

Methods

We monitored the two felids, their prey, and human activities, with 380 camera-trap stations, for a total of 175,127 trap days and over an area of 6000 km² in NE China. We used the constraint line method to characterize cattle grazing and human influences on tigers, leopards, and their prey species.

Results

Our results show that, unexpectedly, at least 26 tigers and 42 leopards are present within China, which are confined primarily to a narrow area along the border with Russia. We have further identified that cattle grazing and human disturbances are the key hurdles to the dispersal of the tigers and leopards farther into China where suitable habitat is potentially available.

Conclusions

Amur tigers and leopards are returning to China, indeed, but their long-term resettlement is not likely without active and timely conservation efforts on landscape and regional scales. To overcome the hurdles to the resettlement of tigers and leopards in China, we propose a “Tiger and Leopard Resettlement Program” that will engage the government, local communities, and researchers, so that the long-term sustainability of the Amur tigers and leopards can be ensured.

     

Assessment of antiepileptic drugs as substrates for canine P-glycoprotein

OBJECTIVE: To determine whether antiepileptic drugs (AEDs) are substrates for canine P-glycoprotein (P-gp). Sample Population-OS2.4/Doxo cells (canine osteosarcoma cells induced via exposure to doxorubicin to highly express P-gp). PROCEDURES: Competitive inhibition of rhodamine 123 efflux from OS2.4/Doxo cells was used to determine whether AEDs were substrates for canine P-gp. Flow cytometry was used to quantify mean fluorescence intensity of cells treated with rhodamine alone and in combination with each experimental drug. RESULTS: Known P-gp substrate drugs ivermectin and cyclosporin A altered rhodamine efflux by 90% and 95%, respectively. Experimental drugs altered rhodamine efflux weakly (diazepam, gabapentin, lamotrigine, levetiracetam, and phenobarbital) or not at all (carbamazepine, felbamate, phenytoin, topirimate, and zonisamide). CONCLUSIONS AND CLINICAL RELEVANCE: At clinically relevant doses, it appeared that AEDs were weak substrates (diazepam, gabapentin, lamotrigine, levetiracetam, and phenobarbital) or were not substrates (carbamazepine, felbamate, phenytoin, topirimate, and zonisamide) for canine P-gp. Therefore, it seems unlikely that efficacy of these AEDs is affected by P-gp expression at the blood-brain barrier in dogs.     

Carbon,Fossil Fuel,and Biodiversity Mitigation With Wood and Forests

Life-cycle analyses, energy analyses, and a range of utilization efficiencies were developed to determine the carbon dioxide (CO₂) and fossil fuel (FF) saved by various solid wood products, wood energy, and unharvested forests. Some products proved very efficient in CO₂ and FF savings, while others did not. Not considering forest regrowth after harvest or burning if not harvested, efficient products save much more CO₂ than the standing forest; but wood used only for energy generally saves slightly less. Avoided emissions (using wood in place of steel and concrete) contributes the most to CO₂ and FF savings compared to the product and wood energy contributions. Burning parts of the harvested logs that are not used for products creates an additional CO₂ and FF savings. Using wood substitutes could save 14 to 31% of global CO₂ emissions and 12 to 19% of global FF consumption by using 34 to 100% of the world’s sustainable wood growth. Maximizing forest CO₂ sequestration may not be compatible with biodiversity. More CO₂ can be sequestered synergistically in the products or wood energy and landscape together than in the unharvested landscape. Harvesting sustainably at an optimum stand age will sequester more carbon in the combined products, wood energy, and forest than harvesting sustainably at other ages.