1,720,962 research outputs found
Effect of Cyclic Heat Stress on Hypothalamic Oxygen Homeostasis and Inflammatory State in the Jungle Fowl and Three Broiler-Based Research Lines
Full text linkHeat stress (HS) is devastating to poultry production sustainability due its detrimental effects on performance, welfare, meat quality, and profitability. One of the most known negative effects of HS is feed intake depression, which is more pronounced in modern high-performing broilers compared to their ancestor unselected birds, yet the underlying molecular mechanisms are not fully defined. The present study aimed, therefore, to determine the hypothalamic expression of a newly involved pathway, hypoxia/oxygen homeostasis, in heat-stressed broiler-based research lines and jungle fowl. Three populations of broilers (slow growing ACRB developed in 1956, moderate growing 95RB from broilers available in 1995, and modern fast growing MRB from 2015) and unselected Jungle fowl birds were exposed to cyclic heat stress (36°C, 9 h/day for 4 weeks) in a 2 × 4 factorial experimental design. Total RNAs and proteins were extracted from the hypothalamic tissues and the expression of target genes and proteins was determined by real-time quantitative PCR and Western blot, respectively. It has been previously shown that HS increased core body temperature and decreased feed intake in 95RB and MRB, but not in ACRB or JF. HS exposure did not affect the hypothalamic expression of HIF complex, however there was a line effect for HIF-1α (P = 0.02) with higher expression in JF under heat stress. HS significantly up regulated the hypothalamic expression of hemoglobin subunits (HBA1, HBBR, HBE, HBZ), and HJV in ACRB, HBA1 and HJV in 95RB and MRB, and HJV in JF, but it down regulated FPN1 in JF. Additionally, HS altered the hypothalamic expression of oxygen homeostasis- up and down-stream signaling cascades. Phospho-AMPK(Thr172) was activated by HS in JF hypothalamus, but it decreased in that of the broiler-based research lines. Under thermoneutral conditions, p-AMPK(Thr172) was higher in broiler-based research lines compared to JF. Ribosomal protein S6K1, however, was significantly upregulated in 95RB and MRB under both environmental conditions. HS significantly upregulated the hypothalamic expression of NF-κB2 in MRB, RelB, and TNFα in ACRB, abut it down regulated RelA in 95RB. The regulation of HSPs by HS seems to be family- and line-dependent. HS upregulated the hypothalamic expression of HSP60 in ACRB and 95RB, down regulated HSP90 in JF only, and decreased HSP70 in all studied lines. Taken together, this is the first report showing that HS modulated the hypothalamic expression of hypoxia- and oxygen homeostasis-associated genes as well as their up- and down-stream mediators in chickens, and suggests that hypoxia, thermotolerance, and feed intake are interconnected, which merit further in-depth investigations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Characterizing and Evaluating Growth Performance and Poultry Production Efficiencies Using Conventional and Novel Monitoring Methods on Modern Broilers and Japanese Quail
Full text linkThe poultry industry is integral to the global agricultural system as consumption rates continue to rise worldwide. With the global population projected to reach 10 billion by 2050, there is an increasing need for efficient and sustainable animal protein sources. Feed efficiency is a significant factor in poultry production costs, as feed accounts for 50 to 70% of total production costs. Given increasing concerns surrounding feed efficiency improvements, there is a focus on the genetic improvement of broiler digestibility to improve nutrient utilization and reduce production costs. Water availability is also of critical concern for the poultry industry, as estimates suggest that freshwater availability needs to increase by ~25 percent to meet the needs of increasing population and production. Although broilers have the lowest water footprint of any meat protein, there is still an opportunity to improve water efficiency in broilers. One study aimed to evaluate the effect of sex on the growth performance and feed efficiency of Japanese quail. Female quails consistently reported higher body weights and feed intake; however, no differences were reported in FCR among male and female quails, suggesting that male quails may have the potential for increased relative feed efficiency. Another study assessed the efficacy of conventional and novel water monitoring systems on commercial broiler strains. The study demonstrates that bell waterers lack accuracy and result in increased water intake. Furthermore, the novel low-flow water monitoring system accurately measures water-related production traits without negatively affecting growth performance. Lastly, a final study examined the influence of conventional and novel water monitoring methods on the processing performance of commercial broiler strains. Research results show that water monitoring methods have minimal impact on processing performance and meat quality. These results are encouraging in that the novel low-flow water monitoring system is an accurate and viable method of measuring water intake in poultry. The poultry industry has made significant strides in improving efficiency and sustainability; however, further research into resource sustainability is critical for ensuring food security and reduced environmental impacts in the face of an increasing global population and resource scarcity
Characterizing and Evaluating Growth Performance and Poultry Production Efficiencies Using Conventional and Novel Monitoring Methods on Modern Broilers and Japanese Quail
Full text linkThe poultry industry is integral to the global agricultural system as consumption rates continue to rise worldwide. With the global population projected to reach 10 billion by 2050, there is an increasing need for efficient and sustainable animal protein sources. Feed efficiency is a significant factor in poultry production costs, as feed accounts for 50 to 70% of total production costs. Given increasing concerns surrounding feed efficiency improvements, there is a focus on the genetic improvement of broiler digestibility to improve nutrient utilization and reduce production costs. Water availability is also of critical concern for the poultry industry, as estimates suggest that freshwater availability needs to increase by ~25 percent to meet the needs of increasing population and production. Although broilers have the lowest water footprint of any meat protein, there is still an opportunity to improve water efficiency in broilers. One study aimed to evaluate the effect of sex on the growth performance and feed efficiency of Japanese quail. Female quails consistently reported higher body weights and feed intake; however, no differences were reported in FCR among male and female quails, suggesting that male quails may have the potential for increased relative feed efficiency. Another study assessed the efficacy of conventional and novel water monitoring systems on commercial broiler strains. The study demonstrates that bell waterers lack accuracy and result in increased water intake. Furthermore, the novel low-flow water monitoring system accurately measures water-related production traits without negatively affecting growth performance. Lastly, a final study examined the influence of conventional and novel water monitoring methods on the processing performance of commercial broiler strains. Research results show that water monitoring methods have minimal impact on processing performance and meat quality. These results are encouraging in that the novel low-flow water monitoring system is an accurate and viable method of measuring water intake in poultry. The poultry industry has made significant strides in improving efficiency and sustainability; however, further research into resource sustainability is critical for ensuring food security and reduced environmental impacts in the face of an increasing global population and resource scarcity
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Investigating Growth Performance and Intestinal Barrier Integrity in Heat-stressed Modern Broilers and Their Ancestor Jungle Fowl
Full text linkHeat stress (HS) has a negative effect on poultry production sustainability due to its adverse consequence on bird welfare, health, growth, and mortality. Although modern broilers have greater gut mass and higher energy use efficiency than unselected birds, they are more vulnerable to HS that induces “leaky gut syndrome,” or increased intestinal permeability. The aim of the current study was to determine the effect of HS on growth performance and gut barrier integrity in three modern broiler lines and their ancestor the Jungle Fowl. Four chicken populations including Giant Jungle Fowl (JF), Athens Canadian Random Bred (ACRB), 1995 Arkansas Random Bred (95RAN), and Modern Random Bred (MRB) were studied. Day-old male broiler chicks from each population were raised under thermoneutral (TN) conditions with feed intake, water intake, and temperature measured daily. On day 28 the birds were subjected to one of two environment conditions: TN (24°C) or acute HS (2 hrs at 36°C). After two hours, samples from each section of the small intestine were harvested from two birds per line per treatment and flash frozen in liquid nitrogen. Following 28, the remaining birds were grown out to 56, during which birds were subjected to chronic cyclic HS (8 hrs a day at 36ºC). Growth performance, metabolite and blood hormone concentrations, and molecular data were analyzed by two-way ANOVA. These data show the significant effect HS had on growth performance and intestinal barrier integrity of the studied modern broilers. Acute HS was shown to decrease performance in the modern broilers and had significant effect on mRNA and protein expression of heat shock, tight junction, gap junction, and other intestinal barrier associated proteins. These data provide evidence for a mechanistic understanding of gut barrier physiology and how it can be influenced by growth-rate and heat stress
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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