Efficacy of l-glutamic acid,N,N-diacetic acid to improve the dietary trace mineral bioavailability in broilers     

Gavin M Boerboom  Ronald Busink  Coen H Smits  Wouter H Hendriks  Javier Martín-Tereso 《Journal of animal science》2020,98(12)

Trace minerals are commonly supplemented in the diets of farmed animals in levels exceeding biological requirements, resulting in extensive fecal excretion and environmental losses. Chelation of trace metal supplements with ethylenediaminetetraacetic acid (EDTA) can mitigate the effects of dietary antagonists by preserving the solubility of trace minerals. Lack of EDTA biodegradability, however, is of environmental concern. l-Glutamic acid, N,N-diacetic acid (GLDA) is a readily biodegradable chelating agent that could be used as a suitable alternative to EDTA. The latter was tested in sequential dose–response experiments in broiler chickens. Study 1 compared the effect of EDTA and GLDA in broilers on supplemental zinc availability at three levels of added zinc (5, 10, and 20 ppm) fed alone or in combination with molar amounts of GLDA or EDTA equivalent to chelate the added zinc, including negative (no supplemental zinc) and positive (80 ppm added zinc) control treatments. Study 2 quantified the effect of GLDA on the availability of native trace mineral feed content in a basal diet containing no supplemental minerals and supplemented with three levels of GLDA (54, 108, and 216 ppm). In study 1, serum and tibia Zn clearly responded to the increasing doses of dietary zinc with a significant response to the presence of EDTA and GLDA (P < 0.05). These results are also indicative of the equivalent nutritional properties between GLDA and EDTA. In study 2, zinc levels in serum and tibia were also increased with the addition of GLDA to a basal diet lacking supplemental trace minerals, where serum zinc levels were 60% higher at the 216 ppm inclusion level. Similar to the reported effects of EDTA, these studies demonstrate that dietary GLDA may have enhanced zinc solubility in the gastrointestinal tract and subsequently enhanced availability for absorption, resulting in improved nutritional zinc status in zinc-deficient diets. As such, GLDA can be an effective nutritional tool to reduce supplemental zinc levels in broiler diets, thereby maintaining health and performance while reducing the environmental footprint of food-producing animals.  相似文献   

Preparation of 2H-furo[2,3-c]pyran-2-one derivatives and evaluation of their germination-promoting activity     

Flematti GR  Goddard-Borger ED  Merritt DJ  Ghisalberti EL  Dixon KW  Trengove RD 《Journal of agricultural and food chemistry》2007,55(6):2189-2194

The butenolide, 3-methyl-2H-furo[2,3-c]pyran-2-one (1), has recently been identified as the germination stimulant present in smoke that promotes the germination of seeds from a wide range of plant species. In this paper, we describe the preparation of a number of analogues of 1 and compare their efficacy in promoting seed germination of three highly smoke-responsive plant species, Lactuca sativa L. cv. Grand Rapids (Asteraceae), Emmenanthe penduliflora Benth. (Hydrophyllaceae), and Solanum orbiculatum Poir. (Solanaceae). The results show that the methyl substituent at C-3 in 1 is important for germination-promoting activity while substitution at C-7 reduces activity. In contrast, bioactivity is mostly retained with analogues substituted at C-4 or C-5.  相似文献   

Evaluation of resistance to Phomopsis stem blight (caused by Diaporthe toxica) in Lupinus albus     

Raymond B. Cowley  Gavin J. Ash  John D. I. Harper  David J. Luckett 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(3):631-644

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Ontogenetic behaviour and swimming ability of the endangered eastern freshwater cod,Maccullochella ikei,with notes on growth and development     

Gavin L. Butler  Stuart J. Rowland  Peter R. Baverstock  Stephen Morris 《Ecology of Freshwater Fish》2012,21(1):23-33

Abstract – Understanding the larval ecology of individual fish species is fundamental in ensuring their long‐term conservation. The endangered eastern freshwater cod, Maccullochella ikei, is endemic to the Clarence and Richmond River systems of north‐eastern New South Wales, Australia. Little is known about the behaviour of larval M. ikei in the wild, particularly before and after the swim‐up stage, and following dispersal from the nest site. The aims of this study were to quantify the swimming ability, depth selection, light preference and substrate selection of hatchling to day‐30 M. ikei under controlled laboratory conditions, and to describe its growth and development over the same period. Maccullochella ikei larvae grew constantly but not consistently during the experiment. Exogenous feeding commenced around day 12, prior to the full exhaustion of the yolk. Maximal swimming ability improved daily, but maximum swimming speed declined significantly between days 12 and 13 and remained low. Maccullochella ikei larvae were initially photonegative but were positively phototactic by day 10. Depth selection was for the benthos until day 8, beyond which time larvae dispersed to all depths when released. Substrate selection was for sand in younger larvae but changed to upstream substrates as the experiment progressed. The results of the current study suggest that the period between day 10 and day 20 is critical in the early ontogeny of M. ikei, when it switched phototrophic behaviour, transitioned from endogenous to exogenous feeding and experienced a decline in swimming ability.  相似文献   

Summer ice and carbon dioxide   总被引：1，自引：0，他引：1  

Kukla G  Gavin J 《Science (New York, N.Y.)》1981,214(4520):497-503

The extent of Antarctic pack ice in the summer, as charted from satellite imagery, decreased by 2.5 million square kilometers between 1973 and 1980. The U.S. Navy and Russian atlases and whaling and research ship reports from the 1930's indicate that summer ice conditions earlier in this century were heavier than the current average. Surface air temperatures along the seasonally shifting belt of melting snow between 55 degrees and 80 degrees N during spring and summer were higher in 1974 to 1978 than in 1934 to 1938. The observed departures in the two hemispheres qualitatively agree with the predicted impact of an increase in atmospheric carbon dioxide. However, since it is not known to, what extent the changes in snow and ice cover and in temperature can be explained by the natural variability of the climate system or by other processes unrelated to carbon dioxide, a cause-and-effect relation cannot yet be established.  相似文献   

Habitat selection by spotted owls after a megafire reflects their adaptation to historical frequent-fire regimes     

Jones  Gavin M.  Kramer  H. Anu  Whitmore  Sheila A.  Berigan  William J.  Tempel  Douglas J.  Wood  Connor M.  Hobart  Brendan K.  Erker  Tedward  Atuo  Fidelis A.  Pietrunti  Nicole F.  Kelsey  Rodd  Gutiérrez  R. J.  Peery  M. Zachariah 《Landscape Ecology》2020,35(5):1199-1213

Context

Climate and land-use change have led to disturbance regimes in many ecosystems without a historical analog, leading to uncertainty about how species adapted to past conditions will respond to novel post-disturbance landscapes.

Objectives

We examined habitat selection by spotted owls in a post-fire landscape. We tested whether selection or avoidance of severely burned areas could be explained by patch size or configuration, and whether variation in selection among individuals could be explained by differences in habitat availability.

Methods

We applied mixed-effects models to GPS data from 20 spotted owls in the Sierra Nevada, California, USA, with individual owls occupying home ranges spanning a broad range of post-fire conditions after the 2014 King Fire.

Results

Individual spotted owls whose home ranges experienced less severe fire (<?5% of home range severely burned) tended to select severely burned forest, but owls avoided severely burned forest when more of their home range was affected (~ 5–40%). Owls also tended to select severe fire patches that were smaller in size and more complex in shape, and rarely traveled?>?100-m into severe fire patches. Spotted owls avoided areas that had experienced post-fire salvage logging but the interpretation of this effect was nuanced. Owls also avoided areas that were classified as open and/or young forest prior to the fire.

Conclusions

Our results support the hypothesis that spotted owls are adapted to historical fire regimes characterized by small severe fire patches in this region. Shifts in disturbance regimes that produce novel landscape patterns characterized by large, homogeneous patches of high-severity fire may negatively affect this species.

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USE OF MAGNETIC RESONANCE ANGIOGRAPHY FOR DIAGNOSIS OF PORTOSYSTEMIC SHUNTS IN DOGS     

Bernard  Seguin  DVM  MS  Karen M.  Tobias  DVM  MS  Patrick R.  Gavin  DVM  PhD  Russell L.  Tucker  DVM 《Veterinary radiology & ultrasound》1999,40(3):251-258

A prospective study was conducted to determine the sensitivity and specificity of diagnosis of portosystemic shunts (PSS) and the accuracy of anatomically locating single congenital PSS in dogs using magnetic resonance angiography (MRA). MRA was performed on 10 normal dogs and 23 dogs with PSS. Sensitivity and specificity of MRA to diagnose any shunt among all dogs were 80% and 100%, respectively. Among dogs identified with PSS, sensitivity and specificity of MRA for diagnosis of multiple extrahepatic shunts were 63% and 97%, respectively, and for diagnosis of single congenital shunts were 79% and 100%, respectively. Using MRA, radiologists correctly identified shunts as extrahepatic or intrahepatic in 83% of patients and correctly identified the origin and insertion of the shunts in 57% and 97% of patients, respectively. Use of MRA is specific for diagnosis of PSS and is a sensitive indicator of anatomic location of single congenital portosystemic shunts.  相似文献   

Release of critically endangered crocodiles: Development and application of a food web approach to determine suitability of release habitat     

Paul J. McInerney  Michael E. Shackleton  Gavin N. Rees  Jackson L. Frechette  Han Sam  Leng Hor 《水产资源保护:海洋与淡水生态系统》2019,29(11):1849-1862

Autophagic fungal cell death is necessary for infection by the rice blast fungus   总被引：2，自引：0，他引：2  

Veneault-Fourrey C  Barooah M  Egan M  Wakley G  Talbot NJ 《Science (New York, N.Y.)》2006,312(5773):580-583

Rice blast is caused by the fungus Magnaporthe grisea, which elaborates specialized infection cells called appressoria to penetrate the tough outer cuticle of the rice plant Oryza sativa. We found that the formation of an appressorium required, sequentially, the completion of mitosis, nuclear migration, and death of the conidium (fungal spore) from which the infection originated. Genetic intervention during mitosis prevented both appressorium development and conidium death. Impairment of autophagy, by the targeted mutation of the MgATG8 gene, arrested conidial cell death but rendered the fungus nonpathogenic. Thus, the initiation of rice blast requires autophagic cell death of the conidium.  相似文献   

Media Update     

Gavin Atkins 《Australian veterinary journal》2006,84(3):N18-N18

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