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Scientists have long known that certain pesticides, industrial chemicals and heavy metals have a detrimental impact on the reproductive health of a wide range of species (including humans) by disrupting the endocrine system. As exposure to, and the effects of, ‘endocrine disrupters’ are likely to be more pronounced in wild species with a short gestation period and life-cycle we have chosen to develop non-invasive tools based upon faecal steroid analysis to monitor the reproductive status of the short-tailed field vole (Microtus agrestis). This approach is hoped to eventually provide a sensitive means of detecting environmental disturbances that could adversely affect humans, livestock and wildlife by establishing the the field vole as a terrestrial biomarker. Faecal steroid hormone analysis has already been demonstrated as being a convenient and reliable means of diagnosing reproductive state in a large range of mammalian species (including gazelle, rhino, macaque and mice), however, as of yet little is known regarding the hormonal changes that occur during pregnancy in M. agrestis.
A method for monitoring the reproductive status of female pigs, using non–invasive hormone analysis was developed. Plasma and saliva samples were collected from five reproductively active sows, and analysed for oestradiol–17ß and progesterone by immunoassay. The oestradiol–17ß content of the saliva samples was also measured using a novel biosensor–based method to demonstrate, in principle, the potential to develop an automated system for hormone analysis and interpretation. A hand–held saliva sampling device was designed and built for the purpose of this experiment. Plasma and saliva samples were collected for 3.5 months from four of the five sows. The vascular access port implanted into the fifth sow failed; therefore she could only be used for saliva collection. Saliva sampling was 100% successful for the first two weeks of the study. Over the entire sampling period, daily and twice weekly samples could be collected on 86% of the attempts made. Both progesterone and oestradiol–17ß were measured in saliva samples using conventional immunoassay techniques.
The improvement of neonatal viability by maternal nutrition during gestation has been widely studied in numerous species. Recent investigations have explored the role of long chain omega-3 essential fatty acids (EFAs) in maternal diets during pregnancy. These are the major fatty acids, docosahexaenoic acid (DHA) in particular, in brain and nervous tissue, with specific roles in neural development and cognitive function. Studies in monogastric species have shown that supplementing maternal gestation diets with EFAs positively influences neonatal survival and growth (Rooke et al., 2001), but work in ruminant species is scarce. Previous investigations have predominantly used fish oil as the source of omega-3 EFAs but alternative, more sustainable, sources are desirable. To date, the effect of period of inclusion of EFAs in gestation diets has not been thoroughly explored. The period of rapid brain growth in the ovine foetus occurs between 10 and 6 weeks prior to birth (Turley et al., 1996). This study explored the effects of feeding an algal source of EFAs, with a high content of DHA, during different time periods on measures of lamb viability.
The use of direct fed microbials has been shown to enhance digestion in the ruminant. One source of microbial live populations is a yeast culture Saccharomyces cerevisae (Yea-Sacc1026, CBS 493.94; Alltech Inc, USA), and its use in ruminants has been associated with a range of benefits including an overall increase in dry matter and fiber digestibility (Wiedmeier and Arambel, 1985), combating heat stress in lactating cows (Huber and Higgenbotham, 1985) and increased performance (Fallon and Harte, 1987). Glade and Biesik (1982) working with yearling horses, demonstrated increased DM and N digestibility when S. cerevisae was added to the diet. It was suggested that S. cerevisae enhanced cellulolytic activity, triggering microbial metabolism changes in the horse’s large intestine that enhance hemicellulose fermentation. They also reported that the addition of S. cerevisae results in smaller percentages of absorbed nitrogen excreted in the urine, indicating that the biological value of the S. cerevisae -supplemented diets may be more than the direct contribution of the nitrogen within the yeast itself. The aim of this review is to determine the effects of S. cerevisae on performance parameters of bulls.
The post-weaning growth check causes considerable economic losses in pig production. Some of the problems in susceptibility to disease have been associated with immunoregulation. For example, immaturity of the neonatal immune system, stress-associated and pathogen-induced immunosuppression have all been linked to increased disease susceptibility throughout the early post-weaning period. Studies in both infants and animal models suggest that dietary nucleotides have significant effects on the immune and gastrointestinal systems (see Carver, 1999). It has been suggested that under conditions of limited nucleotide intake, rapid growth or certain disease challenges, dietary (or preformed) nucleotides may spare the cost of de novo nucleotide synthesis and optimise the metabolic function of rapidly dividing tissues such as those of the gastrointestinal and immune systems. The aims of the current study were to determine the effects of a yeast-based nucleotide source (Ascogen™; Chemoforma Ltd, Switzerland) on performance, gut physiology, microflora and immunological parameters in post-weaned piglets.
Feeding strategies for performance horses generally involves the substitution of one-two thirds of the fibrous feeds (e.g., forages and pastures) with starchy materials, primarily cereal grains. Such strategies can result in enhanced susceptibility to colic or laminitis (Kronfeld and Harris, 1997) which can be reduced through the use of beneficial microbial combinations that increase nutrient availability, modify gut microflora and enhance performance. One source of microbial live populations is a yeast culture Saccharomyces cerevisae (Yea-Sacc 1026; CBS 493.94, Alltech Inc, USA) which has been shown to increase the digestibility of gross energy (GE) and enhance the retention of N in yearling horses (Glade and Biesik, 1986), together with enhanced performance. The aim of this review is to determine the effects of S. cerevisae on the digestibility of nutrients in the mare, and subsequent effects on milk composition, quality and performance of the offspring.
Evidence from studies involving zinc supplementation is equivocal. Carlson et al., (1999) stated that both early- and traditionally weaned pigs must be fed 3,000 ppm Zn for at least the first 2 weeks after weaning to enhance growth. Others have also demonstrated that weanling pigs exhibit increased growth performance when fed pharmacoloigcal concentrations of zinc (Zn) as zinc oxide (ZnO) (e.g. Hahn and Baker, 1993). However, the mode of action has not yet been fully elucidated. Specifically, there is no research available on the effects of pharmacological Zn concentrations on piglet gut morphology and gut microflora load. Accordingly a preliminary study was designed to examine the effects of dietary Zn and growth-promotant levels of avilamycin supplementation on gut morphological characteristic (villus height, width and crypt depth), together with gut microlflora characteristics, and digesta pH which is an independent factor influencing microflora colonisation.
Newly weaned piglet diets are normally highly digestible, and as such are composed of ingredients with high acid-binding capacities (Bolduan et al., 1988), which are potentially detrimental to the maintenance of a low gastric pH. The most active element effecting the phenomenon of acid-binding capacity (ABC) is calcium, and a high concentration in pig starter diets can significantly reduce post-weaning growth performance (Hardy, 1992). However, the mechanism by which ABC retards growth performance is largely unknown. Accordingly a preliminary study was designed to examine the effects of ABC on gut morphological characteristics such as villous height, width and crypt depth, together with digesta pH which is an independent factor influencing microflora colonisation.
Actigen™ is a second generation, unique bioactive fraction derived from the outer cell wall of a specific strain of yeast, Saccharomyces cerevisiae, where it acts in the gut to bind pathogenic bacteria, preventing disease and competition for nutrients. In the current trial, 260 sows were used and fed either an unsupplemented control diet or one containing Actigen™ at 0.08% of the formulation during gestation, farrowing and lactation, to assess its impact on sow and piglet performance. Results showed significant increases in feed intake for sows fed Actigen™ pre-farrowing, but this was reversed during lactation, leading to a 7 kg saving in feed intake per animal. At birth, piglets weighed 42 g more in litters from Actigen™-fed sows compared to the control group. Weaning weight of the total litter from Actigen™ sows was significantly higher (P< 0.05) by 3.3 kg, although individual piglet weights were the same. Sows showed no significant loss in body weight during the trial, indicating that the improved piglet production was related to improved nutrient availability and perhaps Ig status of piglets due to the addition of Actigen™ in the diet.
‘How am I supposed to collect qualitative data? It all sounds a bit scary, I know where I am with the numbers we collect.’
‘I don't have time to collect lots of detailed accounts of what people do.’
‘Is qualitative data any use to me? I'm not sure what I would do with it even if I had it.’
Qualitative approaches to research, evaluation and audit are concerned with the ‘why’ and the ‘how’ of what people do. This approach to research aims to explore issues or questions in a particular context and provide ‘thick description’ of both the issues or questions and the environment in which they occur. Ryle (1971) separates actions into layers – the first layer, or ‘thin description’, tells us what was done and how often it was done. The second layer, or ‘thick description’, emerges once we begin to explore the context in which it was done, how it was done and why it was done. This level of detail not only allows for deeper understanding but it also allows for transferability of the findings from one context to another if those contexts are sufficiently similar. Transferability is the qualitative equivalent of generalization. For this reason context is important in qualitative research and wherever possible the research should be carried out in the natural setting of research participants, in order to witness the framework of their own multilayered environment. This makes it an ideal approach for practitioner research, as you are already embedded in your context and you can bring understanding and insight to what goes on there. In qualitative research you, as the researcher, are central to the whole process and are able to use all of your knowledge and understanding of a situation to investigate the question and interpret the findings. (For further discussion on the nature and purpose of qualitative research see Denzin and Lincoln, 2011.)
Designing qualitative research
A qualitative research study starts out with a broad map of the research question or topic you want to explore, the context in which you will be exploring it and an indication of how you intend to explore it. Your research question will usually come from something that you've noticed in everyday practice or in the literature you've been reading.
A trial was conducted using 134 pigs from weaning (21 kg) to finishing (105 kg) fed wheat-soy based commercial feeds formulated with either inorganic minerals or lower levels of organic (chelated) forms. Pigs fed the organic mineral diet has significantly higher (P < 0.05) average daily gain (ADG) compared to those receiving the inorganic control diet between day 31 and 64 of the trial period. The pigs receiving the organic minerals yielded 2 kg extra carcass weight, higher slaughter efficiency (P < 0.05) and greater ham width (P < 0.05). Economic benefits resulted for the organic mineral diets, due to improved performance and reduced mineral inclusion.
A study was conducted to evaluate a natural carbohydrate fraction Actigen™ (NCF), derived from mannanoligosaccharide, in feed on growth performance, intestinal morphology and goblet cell number and area of male broilers'. Dietary treatments included: 1) control diet (antibiotic and NCF free), 2) NCF at 200 g/t, 3) NCF at 400 g/t, and 4) NCF 800 g/t. Two hundred and forty birds were placed into 12 replicate pens per treatment (5 birds/pen), sixty birds per treatment. Body weight and feed intake were recorded weekly up to day 42. At this time a 2.5cm section of jejunum and duodenum were excised post mortem for morphological analysis. Birds fed 200 g/t and 800 g/t NCF were significantly (P < 0.01) heavier from day 14 onwards than the control birds. Feed intake was significantly higher in birds fed 200 g/t NCF compared to those fed the control at 21 and 35 days (P < 0.05). Diets containing 200 g/t and 800 g/t of NCF significantly decreased broiler feed conversion ratio (FCR) compared to the control in the first phase (1–14 days) (P < 0.01) and levels of NCF decreased FCR (P < 0.05) in the second phase (15–28 days). NCF had no significant effect on villus height, villus width, crypt depth or villus to crypt ratio in either duodenum or jejunum. NCF did not significantly affect goblet cell area or goblet cell number in the duodenum, however, in the jejunum, 800 g/t NCF significantly (P < 0.05) increased goblet cell area over the control. In conclusion, NCF showed a positive effect on broiler performance in the starter and grower phases, and increased goblet cell area in the jejunum, suggesting higher levels of mucin production. This indicated that the performance benefit of NCF could be age-dependent, with younger birds responding more than the older ones. There were no additional benefits to performance when feeding NCF for a longer period (after 28 d of age), however it is postulated that birds fed NCF would have greater defence to pathogenic challenge through increased storage capacity of mucin.
Lynntech, Inc has successfully researched and demonstrated a unique method for the manufacture of quasicrystalline (QC) coatings that utilizes the process of electrocodeposition. The purpose of this study was to optimize the physical-mechanical properties of the QC coatings. All metal substrates were aluminum alloy Al-3004 and codeposition was performed using Al65Cu23Fe12 QC powders in nickel plating solutions. X-ray diffraction spectroscopy was performed in order to verify the attachment of quasicrystals to the aluminum alloy substrate and coated samples displayed identical spectra to those of raw QC powders. The average contact angle θ was 117.2° for electrocodeposited QC coatings. Friction was monitored during pin-on-disk wear tests and QC coated samples had coefficients of friction as low as 0.01 and an average value of 0.05 with samples showing no visible wear scar. Lynntech's electrocodeposited quasicrystalline coatings withstand high temperatures and exhibit low wear and friction characteristics with a low surface energy making them ideal for cookware, as well as various other applications such as bearings, landing gear and engine parts, where thermal and mechanical conditions are prime importance.
Certain commercial horse feed supplements based on active yeast and its derivatives, and have been shown to improve digestion of feed (Medina et al, 2002), although this data is very limited and is mostly derived from studies in other species, such as pigs or cattle. Yeast-derived compounds are known to improve digestibility via different mechanisms, depending on their composition. Live yeasts interact at a gut level by removing any oxygen present, which can unbalance the fermentative microflora by promoting aerobic bacterial populations. This can lead to an increase in nonfermentative or pathogenic species, which increases the potential for diarrhoea or other digestive upsets. Yeast cell wall material (mannan-oligosaccharides) have been shown to bind pathogenic bacteria in the digestive tract, inhibiting their ability to reproduce, thereby stabilising the microflora and optimising fermentative capacity for fibre digestion, promoting animal growth and efficiency (Rosen, 2005). As horses rely on anaerobic fermentation to liberate energy from their natural high fibre diets, a stable and appropriate microflora is essential. The aim of the experiment was to investigate the benefits of feeding commercial digestive enhancers in horses with a history of gastric problems.
To determine whether feeding a sustainable, algal source of docosahexaenoic acid (DHA) to sheep during late pregnancy would improve neonatal lamb vigour, 48 English mule ewes, of known conception date, were divided into four treatment groups. For the last 9 weeks of gestation, ewes received one of two dietary supplements: either a DHA-rich algal biomass providing 12 g DHA/ewe per day, or a control supplement based on vegetable oil. The four dietary treatment groups (n = 12) were: control supplement for the duration of the trial (C), DHA supplement from 9 to 6 weeks before parturition (3 week), DHA supplement from 9 to 3 weeks before parturition (6 week) and DHA supplement for the duration of the trial (9 week). Dietary supplements were fed alongside grass silage and commercial concentrate. There was a tendency for gestation length to be extended with increased duration of DHA supplementation (P = 0.08). After parturition, the concentrations of eicosapentaenoic acid (EPA) and DHA in ewe and lamb plasma and colostrum were elevated in line with increased periods of DHA supplementation. Lambs from the 6-week and 9-week groups stood significantly sooner after birth than lambs from the C group (P < 0.05). These data show that neonatal vigour may be improved by the supplementation of maternal diets with DHA-rich algal biomass and that this beneficial effect depends upon the timing and/or duration of DHA allocation.
The objectives of this study were to determine the effect of the chemical form of selenium (Se) fed to sows (1) on production and immune quality of colostrum and (2) on piglet response to a deterioration of sanitary conditions after weaning. Twenty-two pregnant sows were assigned to receive a diet supplemented with 0.3 ppm Se from either sodium selenite (inorganic Se) or Se-enriched yeast (organic Se as Sel-Plex®; Alltech Inc., Nicholasville, KY, USA). Dietary treatments were applied during the last month of pregnancy and lactation. Blood samples were collected on sows before dietary treatment, on the day of weaning and 6 weeks later, and on three to five piglets within litters at birth, at weaning and 6 weeks post weaning. Whole blood was analysed for Se concentration. Colostrum samples were collected at 0, 3, 6 and 24 h post partum and milk samples on days 14 and 27 of lactation. Colostrum and milk were analysed for Se and immunoglobulin G (IgG) concentrations. At weaning, 40 pairs of littermate piglets were moved to rooms where sanitary conditions were good or purposely deteriorated. Piglets were reared individually and fed ad libitum. After 15 days, piglets and feed refusals were weighed and a blood sample was collected to measure plasma haptoglobin concentration. When sows were fed organic Se, Se concentrations were increased by 33% in colostrum (P < 0.05), 89% in milk (P < 0.001) and by 28% in whole blood of piglets at weaning (P < 0.001). Colostrum production during the 24 h after the onset of farrowing and IgG concentrations in colostrum and milk did not significantly differ between the two groups of sows. Weaned piglets reared in good sanitary conditions grew faster (P < 0.001) than piglets housed in poor conditions. Sanitary conditions did not influence mean plasma haptoglobin concentrations of piglets (P > 0.1). The source of Se fed to the dams did not influence piglet performance or haptoglobin concentrations after weaning. These findings confirm that, compared with inorganic Se, organic Se fed to the dam is better transferred to colostrum and milk, and consequently to piglets. They indicate that the Se source influences neither colostrum production nor IgG concentrations in colostrum, and that the higher Se contents of piglets does not limit the reduction of growth performance when weaning occurs in experimentally deteriorated sanitary conditions.
Since shunting is almost a purely mechanical treatment that radically affects pressure–volume compensation, patients’ cerebrospinal fluid hydrodynamics compensation should be examined before a shunt is implanted. Apart from an opening pressure and a resistance to cerebrospinal fluid outflow, pulse amplitude of intracranial pressure and the content of vasogenic waves are useful to gauge cerebrospinal fluid dynamics. Infusion studies, although invasive, may help with the decision about surgery. They also provide basic information for further management of shunted patients, when complications, such as shunt blockage, under- and over-drainage, arise.