Evaluation of vitamin A status on myogenic gene expression and muscle fiber characteristics     

Kimberly B Wellmann  Jongkyoo Kim  Phil M Urso  Zachary K Smith  Bradley J Johnson 《Journal of animal science》2021,99(3)

A randomized complete block design experiment with 30 yearling crossbred steers (average BW = 436.3 ± 39.8 kg) fed a steam-flaked corn-based diet was used to evaluate the effects dietary vitamin A (Rovimix A 1000; DSM Nutritional Products Ltd., Sisseln, SUI) supplementation on myogenic gene expression and skeletal muscle fiber characteristics during the finishing phase. Steers were blocked by BW (n = 5 blocks; 6 steers/block), randomly assigned to pens (n = 2 steers/pen), and one of the following treatments: no added vitamin A (0 IU; 0.0 IU/kg of dietary dry matter intake of additional vitamin A), vitamin A supplemented at the estimated requirement (2,200 IU; 2,200 IU/kg of dietary dry matter (DM) of additional vitamin A), and vitamin A supplemented at 5× the estimated requirement (11,000 IU; 11,000 IU/kg of dietary DM of additional vitamin A). After all treatments underwent a 91-d vitamin A depletion period, additional vitamin A was top-dressed at feeding via a ground corn carrier. Blood, longissimus muscle, and liver biopsy samples were obtained on days 0, 28, 56, 84, and 112. Biopsy samples were used for immunohistochemical and mRNA analysis. Sera and liver samples were used to monitor circulating vitamin A and true vitamin A status of the cattle. Expression for myosin heavy chain (MHC)-I diminished and rebounded (P = 0.04) over time. The intermediate fiber type, MHC-IIA, had a similar pattern of expression (P = 0.01) to that of MHC-I. On day 84, C/EBPβ expression was also the greatest (P = 0.03). The pattern of PPARγ (P < 0.01) and PPARδ (P < 0.01) expression seemed to mimic that of MHC-I expression, increasing from days 84 to 112. Distribution of MHC-IIA demonstrated a change over time (P = 0.02). Muscle fiber cross-sectional area increased by day (P < 0.01) for each MHC with the notable increase between days 0 and 56. Total nuclei density decreased (P = 0.02) over time. Cells positive for only Myf5 increased (P < 0.01) in density early in the feeding period, then declined, indicating that satellite cells were fusing into fibers. The dual-positive (PAX7+Myf5) nuclei also peaked (P < 0.01) around day 56 then declined. These data indicated that gene expression associated with oxidative proteins may be independent of vitamin A status in yearling cattle.  相似文献   

Landscape capability models as a tool to predict fine-scale forest bird occupancy and abundance     

Zachary G. Loman  William V. Deluca  Daniel J. Harrison  Cynthia S. Loftin  Brian W. Rolek  Petra B. Wood 《Landscape Ecology》2018,33(1):77-91

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Ocular dermoids in dogs: A retrospective study     

Zachary Badanes  Eric C. Ledbetter 《Veterinary ophthalmology》2019,22(6):760-766

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Using visual-based social norm methods to understand distance-related human–wildlife interactions     

Zachary D. Miller  Wayne Freimund 《Human Dimensions of Wildlife》2018,23(2):176-186

Distance-related human–wildlife interactions are a challenge in diverse settings across the globe. However, few methodological approaches have been proposed to explore the issue of distance in human dimensions research. Drawing from previous research related to crowding, noise pollution, and other visitor experience concepts, this methodological article describes a novel visual-based social norm method for evaluating distance-related human–wildlife interactions. We discuss the process of constructing the tools, the field testing of the techniques in Yellowstone National Park, and reflect on the methodological approach. From these methods, practitioners can gain information about distance thresholds of visitors in relation to wildlife viewing and potentially help identify deviant groups of visitors. Future research directions include pre-post research designs, controlled experiments, and belief evaluations for improving communications.  相似文献   

Seasonal effects of macrophyte growth on rainbow trout habitat availability and selection in a low‐gradient,groundwater‐dominated river          下载免费PDF全文

Zachary J. Kuzniar  Robert W. Van Kirk  Eric B. Snyder 《Ecology of Freshwater Fish》2017,26(4):653-665

Rainbow trout habitat use is often described in high‐gradient, runoff‐driven, heterotrophic streams where geomorphic features and overhanging riparian vegetation provide channel complexity and cover. However, many rainbow trout populations thrive in rivers with contrasting aquatic habitat. We describe rainbow trout habitat use in a low‐gradient, groundwater‐dominated tailwater river where river flow management and macrophyte growth and senescence largely govern available trout habitat. In the summers of 2013 and 2014, available aquatic habitat (depth, velocity, macrophyte cover, substrate size) was quantified, while individual trout location was determined by radio telemetry and linked to environmental variables. Detailed habitat surveys indicate that macrophyte cover increases throughout the summer and is a strong determinant of in‐stream habitat characteristics. Paired logistic regression shows that adult rainbow trout prefer greater depths. Water depth increases with macrophyte abundance at both reach and local scales as plants restrict flow, and available trout habitat is linked to this seasonal pattern. When macrophyte abundance is high, adult trout show secondary preference for localised areas of lower macrophyte cover but otherwise show no selectivity for macrophyte cover, velocity or substrate size. Results suggest that submerged aquatic plants increased the quantity and quality of rainbow trout habitat as a source of channel complexity and cover. Macrophytes may play a similar role in other low‐gradient streams and should not be overlooked by fisheries managers considering habitat suitability.  相似文献   

Applicability of a multiplex PCR to detect O26, O45, O103, O111, O121, O145, and O157 serogroups of Escherichia coli in cattle feces     

Paddock Z  Shi X  Bai J  Nagaraja TG 《Veterinary microbiology》2012,156(3-4):381-388

Shiga toxin-producing Escherichia coli (STEC), particularly O157, are major food borne pathogens. Non-O157 STEC, particularly O26, O45, O103, O111, O121, and O145, have also been recognized as a major public health concern. Unlike O157, detection procedures for non-O157 have not been fully developed. Our objective was to develop a multiplex PCR to distinguish O157 and the 'top six' non-O157 serogroups (O26, O45, O103, O111, O121, and O145) and evaluate the applicability of the multiplex PCR to detect the seven serogroups of E. coli in cattle feces. Published sequences of O-specific antigen coding genes, rfbE (O157) and wzx and wbqE-F (non-O157), were analyzed to design serogroup-specific primers. The specificity of amplifications was confirmed with 138 known STEC strains and the reaction yielded the expected amplicons for each serogroup. In feces spiked with pooled 7 STEC strains, the sensitivity of the detection was 4.1 × 10(5)CFU/g before enrichment and 2.3 × 10(2) after 6h enrichment in E. coli broth. Additionally, 216 fecal samples from cattle were collected and tested by multiplex PCR and cultural methods. The multiplex PCR revealed a high prevalence of all seven serogroups (178 [O26], 108 [O45], 149 [O103], 30 [O111], 103 [O121], 5 [O145], and 160 [O157]) of 216 samples in fecal samples. Cultural procedures identified 33.1% (53/160) and 35.5% (11/31) of PCR-positive samples for E. coli O157 and non-O157 serogroups, respectively. Samples that were culture-positive were all positive by the multiplex PCR. The multiplex PCR can be used to identify serogroups of putative STEC isolates.  相似文献   

In vitro effects of oxytetracycline on matrix metalloproteinase-1 mRNA expression and on collagen gel contraction by cultured myofibroblasts obtained from the accessory ligament of foals     

Arnoczky SP  Lavagnino M  Gardner KL  Tian T  Vaupel ZM  Stick JA 《American journal of veterinary research》2004,65(4):491-496

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Evaluating alternative methods for biophysical and cultural ecosystem services hotspot mapping in natural resource planning     

Kenneth J. Bagstad  Darius J. Semmens  Zachary H. Ancona  Benson C. Sherrouse 《Landscape Ecology》2017,32(1):77-97

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How commercial fishing effort is managed     

Christopher M. Anderson  Melissa J. Krigbaum  Martin C. Arostegui  Megan L. Feddern  John Zachary Koehn  Peter T. Kuriyama  Christina Morrisett  Caitlin I. Allen Akselrud  Melanie J. Davis  Courtney Fiamengo  Ava Fuller  Qi Lee  Katherine N. McElroy  Maite Pons  Jessica Sanders 《Fish and Fisheries》2019,20(2):268-285

Wild capture fisheries produce 90 million tonnes of food each year and have the potential to provide sustainable livelihoods for nearly 40 million people around the world ( http://www.fao.org/3/a-i5555e.pdf ). After decades of overfishing since industrialization, many global fish stocks have recovered, a change brought about through effective management. We provide a synthetic overview of three approaches that managers use to sustain stocks: regulating catch and fishing mortality, regulating effort and regulating spatial access. Within each of these approaches, we describe common restrictions, how they alter incentives to change fishing behaviour, and the resultant ecological, economic and community‐level outcomes. For each approach, we present prominent case‐studies that illustrate behaviour and the corresponding performance. These case‐studies show that sustaining target stocks requires a hard limit on fishing mortality under most conditions, but that additional measures are required to generate economic benefits. Different systems for allocation allow stakeholder communities to strike a locally acceptable balance between profitability and employment.  相似文献   

Marine recreational fishing and the implications of climate change     

Bryony L. Townhill  Zachary Radford  Gretta Pecl  Ingrid van Putten  John K. Pinnegar  Kieran Hyder 《Fish and Fisheries》2019,20(5):977-992

Marine recreational fishing is popular globally and benefits coastal economies and people's well‐being. For some species, it represents a large component of fish landings. Climate change is anticipated to affect recreational fishing in many ways, creating opportunities and challenges. Rising temperatures or changes in storms and waves are expected to impact the availability of fish to recreational fishers, through changes in recruitment, growth and survival. Shifts in distribution are also expected, affecting the location that target species can be caught. Climate change also threatens the safety of fishing. Opportunities may be reduced owing to rougher conditions, and costs may be incurred if gear is lost or damaged in bad weather. However, not all effects are expected to be negative. Where weather conditions change favourably, participation rates could increase, and desirable species may become available in new areas. Drawing on examples from the UK and Australia, we synthesize existing knowledge to develop a conceptual model of climate‐driven factors that could impact marine recreational fisheries, in terms of operations, participation and motivation. We uncover the complex pathways of drivers that underpin the recreational sector. Climate changes may have global implications on the behaviour of recreational fishers and on catches and local economies.  相似文献