Effect of feeding systems on omega-3 fatty acids, conjugated linoleic acid and trans fatty acids in Australian beef cuts: potential impact on humnan health

The influence of feeding systems on the levels of functional lipids and other fatty acid concentrations in Australian beef was examined. Rump, strip loin and blade cuts obtained from grass feeding, short-term grain feeding (80 days; STGF) and long-term grain feedlot rations (150-200 days; LTFL) were used in the present study. The typical Australian feedlot ration contains more than 50% barley and/or sorghum and balanced with whole cottonseed and protein meals were used as feed for STGF and LTFL regimens. Meat cuts from 18 cattle for each feeding regimen were trimmed of visible fat and  connective tissue and then minced (300 g lean beef); replicate samples of 7g were used for fatty acid (FA) analysis. There was a significantly higher level of total omega-3 (n-3) and long chain n-3 FA in grass-fed beef (P <0.0001) than the grain-fed groups regardless of cut types. Cuts from STGF beef had significantly reduced levels of n-3 FA and conjugated linoleic acid (CLA) and similar levels of saturated, monounsaturated and n-6 FA compared with grass feeding (P <0.001). Cuts from LTFL beef had higher levels of saturated, monounsaturated, n-6 FA and trans 18:1 than similar  cuts from the other two groups (P <0.01), indicating that increased length of grain feeding was associated with more fat deposited in the carcass. There was a step-wise increase in trans 18:1 content from grass to STGF to LTGF, suggesting grain feeding elevates trans FA in beef, probably because of increased intake of 18:2n-6. Only grass-fed beef reached the target of more than 30mg of long chain n-3 FA/100 g muscle as recommended by Food Standard Australia and New Zealand for a food to be considered a source of omega- 3 fatty acids. The proportions of trans 18:1 and n-6 FA were higher (P<0.001) for both grain-fed beef groups than grass-fed beef. Data from the present study show that grain feeding decreases functional lipid  components (long chain n-3 FA and CLA) in Australian beef regardless of meat cuts, while increasing total trans 18:1 and saturated FA levels.

Comparison of the color stability and lipid oxidative stability fo fresh and vacuum packaged lamb muscle containing elevated omega-3 and omega-6 fatty acid levels from dietary manipulation

A series of three experiments were conducted with second cross ([Merino×Border Leicester]×Poll Dorset) wether lambs to evaluate the effects of dietary treatments on manipulation of muscle long-chain (LC) omega-3 fatty acids (FA) on the color stability and oxidative stability of fresh and vacuum packaged lamb. At the end of 7-, 6- and 6-week experimental periods for experiments (Exp.) 1–3 respectively, lambs were slaughtered at a commercial abattoir. At 24 h post-mortem, muscle longissimus lumborum (LL) and longissimus thoracis (LT) were removed and evaluated for color and lipid oxidative stability under specified commercial storage and display condition. Of the dietary supplements used, fish meal and fish oil moderately (P<0.01) and markedly (P<0.001) increased muscle omega-3 FA content, while both protected canola seed (P<0.001) and protected sunflower meal protein significantly (P<0.02) increased muscle omega-6 FA content or ratio of omega-6/omega-3 of the longissimus muscle. In all experiments, the substantial increase (P<0.001) in muscle LC omega-3 and omega-6 FA had no consistent significant effect on color values (redness (a*), yellowness (b*) and lightness (L*)) for fresh and vacuum packaged lamb over a 6-day display period. Lipid oxidation, determined by the levels of thiobarbituric acid reactive substances (TBARS) indicated the enrichment of muscle polyunsaturated fatty acid (PUFA) levels in lambs did not produce significant differences resulting either from main treatment effects or for treatment×day×type interactions (where type was fresh and vacuum packaged). Present results demonstrated the color and lipid oxidative stability of lamb longissimus muscle during refrigerated display was not affected by enhanced levels of omega-3 and omega-6 FA due to dietary treatments.

Growth and product quality of European eel (Anguilla anguilla) as affected by dietary protein and lipid sources

A 12-week feeding trial was undertaken to evaluate the effects of partial replacement of marine raw materials in the diet with soybean meal and beef tallow on growth and product quality of European eel (Anguilla anguilla ). Based on growth, feed efficiency and chemical composition, soybean meal was found to be an unsuitable ingredient for eel diets as a substitute for fishmeal (25% on a protein basis), probably because of the low digestibility of its carbohydrate content. However, beef tallow can be used to replace 50% of fish oil without reduction in growth, provided that digestible carbohydrates are present in the diet. No major effects of protein and lipid sources in the diet were found on fillet chemical composition. Sensory analysis revealed no significant differences between fish fed the control and the experimental diets, with the exception of salty taste which was significantly higher in fish fed combined soybean meal and beef tallow compared with fish fed the control diet.

The effect of training in reduced energy density eating and food self-monitoring accuracy on weight loss maintenance

Background:
Failure to maintain weight losses in lifestyle change programs continues to be a major problem and warrants investigation of innovative approaches to weight control.
Objective:
The goal of this study was to compare two novel group interventions, both aimed at improving weight loss maintenance, with a control group.
Methods and Procedures:
A total of 103 women lost weight on a meal replacement–supplemented diet and were then randomized to one of three conditions for the 14-week maintenance phase: cognitive-behavioral treatment (CBT); CBT with an enhanced food monitoring accuracy (EFMA) program; or these two interventions plus a reduced energy density eating (REDE) program. Assessments were conducted periodically through an 18-month postintervention. Outcome measures included weight and self-reported dietary intake. Data were analyzed using completers only as well as baseline-carried-forward imputation.
Results:
Participants lost an average of 7.6 plusminus 2.6 kg during the weight loss phase and 1.8 plusminus 2.3 kg during the maintenance phase. Results do not suggest that the EFMA intervention was successful in improving food monitoring accuracy. The REDE group decreased the energy density (ED) of their diets more so than the other two groups. However, neither the REDE nor the EFMA condition showed any advantage in weight loss maintenance. All groups regained weight between 6- and 18-month follow-ups.
Discussion:
Although no incremental weight maintenance benefit was observed in the EFMA or EFMA + REDE groups, the improvement in the ED of the REDE group's diet, if shown to be sustainable in future studies, could have weight maintenance benefits.

Increased probiotic yogurt or resistant starch intake does not affect isoflavone bioavailability in subjects consuming a high soy diet

Objective - Probiotics and prebiotics that affect gut microflora balance and its associated enzyme activity may contribute to interindividual variation in isoflavone absorption after soy intake, possibly enhancing isoflavone bioavailability. This study examined the effects of the consumption of bioactive yogurt (a probiotic) or resistant starch (a known prebiotic) in combination with high soy intake on soy isoflavone bioavailability.

Methods - Using a crossover design, chronic soy consumption was compared with soy plus probiotic yogurt or resistant starch in older male and postmenopausal females (n = 31). Isoflavone bioavailability was assessed at the beginning and end of each 5-wk dietary period by sampling plasma and urine after a standardized soy meal.

Results - Chronic soy intake did not significantly affect plasma or urinary isoflavones after the soy meal and there were no significant effects of probiotic or resistant starch treatment. However, there were trends for increased circulating plasma daidzein and genistein after the probiotic treatment and for increased plasma daidzein and genistein 24 h after soy intake with resistant starch treatment. Neither treatment induced or increased equol production, although there was a trend for increased plasma equol in “equol-positive” subjects (n = 12) after probiotic treatment.

Conclusion - The weak or absence of effects of probiotic yogurt or resistant starch supplement to a chronic soy diet suggests that gut microflora were not modified in a manner that significantly affected isoflavone bioavailability or metabolism.

The role of fatty acids in satiation and satiety

Background – Satiation and satiety describe the events which lead to meal termination and the maintenance of hunger induced by physical and metabolic events following food ingestion. Fatty acids, components of dietary fat (triglyceride) may be important, if not essential components of satiation and satiety. Emerging evidence suggests fatty acid now constitutes a sixth taste modality and orally sensed fatty acids mediate unique cephalic and hormonal responses priming the body for fat digestion, and may contribute to sensory specific satiety. Once ingested, fatty acids are sensed in the gastrointestinal tract (GIT) where they cause the release of hormones, stimulate the vagus and enter the blood stream where they act a number of organs (brain, liver) to influence satiety.
Objective – To review the role of fatty acids in sensory and metabolic satiation and satiety.
Design – Literature search and review of papers from the past decade on satiety, satiation, fat taste and fatty acids.
Outcomes – The physiological significance of gustatory fat detection is still unclear, but it may signal the nutritious content of fat similar to the tastes of sweet or umami which signal the presence of carbohydrate or proteins. Like other tastants, fatty acid taste sensitivity is thought to vary in the population and differences in sensitivity may influence dietary choice and fat intake. Fatty acid taste may contribute to sensory specific satiety as foods are eaten. Animal models have observed an inverse relationship between oral fatty acid sensitivity and fat consumption, which leads to obesity. Observations that the obese have heightened preferences for, and consume more fat than lean individuals questions whether such a relationship may also be apparent in humans. At the GIT, fatty acids are sensed by enterocytes and bind to receptors, transporters or ion channels where they initiate gut-brain communication over nutrient status through the vagus and cause the release of satiety hormones which lead to meal termination. Inefficient fatty acid sensing at either or both locations is thought to accompany the aetiology of obesity.
Conclusion – Variations in sensitivity to fatty acids may alter preferences and consumption of fats or hormonal responses to fat ingestion which influence sensory-specific, metabolic and subjective satiety.

Urban living and obesity : is it independent of its population and lifestyle characteristics?

OBJECTIVES: Living in an urban area influences obesity. However, little is known about whether this relationship is truly independent of, or merely mediated through, the demographic, socio-economic and lifestyle characteristics of urban populations. We aimed to identify and quantify the magnitude of this relationship in a Sri Lankan population.

METHODS: Cross-sectional study of adults aged 20-64 years representing the urban (n = 770) and rural (n = 630) populations, in the district of Colombo in 2004. Obesity was measured as a continuous variable using body mass index (BMI). Demographic, socio-economic and lifestyle factors were assessed. Gender-specific multivariable regression models were developed to quantify the independent effect of urban/ rural living and other variables on increased BMI.

RESULTS: The BMI (mean; 95% confidence interval) differed significantly between urban (men: 23.3; 22.8-23.8; women: 24.2; 23.7-24.7) and rural (men: 22.3; 21.9-22.7; women: 23.2; 22.7-23.7) sectors (P < 0.01). The observed association remained stable independently of all other variables in the regression models among both men (coefficient = 0.64) and women (coefficient = 0.95). These coefficients equated to 2.2 kg weight for the average man and 1.7 kg for the average woman. Other independent associations of BMI were with income (coefficient = 1.74), marital status (1.48), meal size (1.53) and religion (1.20) among men, and with age (0.87), marital status (2.25) and physical activity (0.96) among women.

CONCLUSIONS: Urban living is associated with obesity independently of most other demographic, socio-economic and lifestyle characteristics of the population. Targeting urban populations may be useful for consideration when developing strategies to reduce the prevalence of obesity.

The effect of food temperature on post-prandial metabolism in albatrosses

Heat generated by the specific dynamic action (SDA) associated with feeding is known to substitute for the thermoregulatory costs of cold-exposed endotherms; however, the effectiveness of this depends on food  temperature. When food is cooler than core body temperature, it is warmed by body heat and, consequently, imposes a thermoregulatory challenge to the animal. The degree to which this cost might be `paid' by SDA depends on the relative timing of food heating and the SDA response. We investigated this phenomenon in two genera of endotherms, Diomedea and Thalassarche albatrosses, by measuring postprandial metabolic rate following ingestion of food at body temperature (40°C) and cooler (0 and 20°C). This permitted us to estimate potential contributions to food warming by SDA-derived heat, and to observe the effect of cold food on metabolic rate. For meal sizes that were ~20% of body mass, SDA was 4.22±0.37% of assimilated food energy, and potentially contributed 17.9±1.0% and 13.2±2.2% of the required heating energy of food at 0°C for Diomedea and Thalassarche albatrosses, respectively, and proportionately greater quantities at higher food temperatures. Cold food increased the rate at which postprandial metabolic rate increased to 3.2–4.5 times that associated with food ingested at body temperature. We also found that albatrosses generated heat in excess by more than 50% of the estimated thermostatic heating demand of cold food, a probable consequence of time delays in physiological responses to afferent signals.

Adaptation to mandated restrictions on smoking in dining areas : results of an Internet survey

Objective : The study aimed to measure changes in dining behaviour associated with the introduction of smoking restrictions on July 1, 2001, to describe strategies adopted by smokers and non-smokers to adapt to the changes, and to describe some of the thoughts, feelings and beliefs underlying the adaptations that people make in response to the introduction of new restrictions.

Method : Data were collected in a longitudinal study with repeated measures of a total of 257 respondents before and after the introduction of the restrictions, using a questionnaire administered via the Internet. Data collection occurred on seven occasions between April 2001 and March 2002. In addition, a series of in-depth telephone interviews was conducted among a group of 31 smokers and non-smokers, who were interviewed once before and twice after the introduction of the bans.

Results : Dining patterns, dining frequency, restaurant choice and expenditure on a meal did not change among either smoking or non-smoking patrons following the introduction of the law. The majority of Victorians approved of smokefree dining legislation before its implementation, and agreement with the law increased sharply and significantly among both smokers and non-smokers immediately following the introduction of the policy, remaining at high levels for the duration of the study period.

Conclusions : These findings suggest there was rapid adaptation to and acceptance of the restrictions among both smokers and non-smokers, and are supported by evidence from other jurisdictions, both interstate and internationally, regarding the introduction of smokefree dining.

Does the inclusion of moderate amounts of red meat in the diet of exercising older women impact on faecal markers of bowel health, including faecal lactoferrin?

Background: High intakes of red meat may be associated with increased risk of colorectal cancer (CRC), however, to determine CRC risk, it is important to assess faecal changes related to protein and carbohydrate metabolism.

Objective: To determine the influence of three weekly meals rich in red meat as opposed to a carbohydrate control diet on faecal markers which are involved in the aetiology of CRC.

Design: Twenty post-menopausal women (aged 60-75) undertook, 3 times a week for 12 weeks, a 30 minute exercise session followed immediately by a cooked meal that was high in lean red meat, low in carbohydrate (n= 10) or low in lean red meat, high in carbohydrate (n=10). Dietary fibre intake and macronutrients were kept constant. At the beginning and end of the study, three-day faecal samples were collected and by-products of protein fermentation and carbohydrate metabolism, undigested fibre residues, and faecal output and colonic bacterial microbiota changes measured.

Outcomes: No significant differences were observed in subjects on either diet when comparing faecal output, faecal pH, other faecal markers, nor faecal lactoferrin. There was a trend observed in changes in the population of colonic microbiota using FISH analysis. Bacteroides spp. and Prevotella spp. appeared to decrease in women consuming a high red meat diet compared with an increase in women consuming a high carbohydrate diet.

Conclusions: In this pilot study the trend in colonic microbiota change is interesting and suggests that dietary influence of colonic microbiota, especially changes in Bacteroidetes, may be indicative of risk of gut damage and disease compared to other faecal markers.

Amylase and glucosidase enzyme inhibitory activity of ginger (Zingiber officinale Roscoe) an in vitro study

The prevalence of type 2 diabetes has reached to an epidemic proportion in Sri Lanka. The need for achieving better control of blood glucose level has been evident in diabetes management. However it is not easy to achieve this goal in a large proportion of patients. This is partly due to limitations of currently available pharmacological agents which stimulate research on novel anti-diabetic agents with different mechanisms. Digestive enzymes have been targeted as potential avenues for modulation of blood glucose concentration through inhibition of the enzymatic breakdown of complex carbohydrates to meal derived glucose absorption. Acarbose is a widely used oral anti-diabetic drug which inhibits the α-glucosidase, enzyme responsible for breaking down of disaccharides and polysaccharides into glucose. Many herbal extracts have been found to posses similar inhibitory effects. Ginger (Zingiber officinale Roscoe) has developed a reputation in treatment of several diseases. In vitro enzymic inhibitory effect of ginger was investigated in this study. Enzymes α -amylase and α -glucosidase treated with either Acarbose or ginger extract were allowed to react with cooked rice and percentages of glucose content were measured. The glucosidase and amylase activities on the rice were inhibited by addition of ginger cause significant reduction in glucose percentages (36.86± 1.05 to 26.87± 2.17, P<0.05 and 49.04±0.65 to 35.35±2.22, P<0.05) which showed comparable results with Acarbose on glucosidase activity (36.86± 1.05 to, 27.8±1.32 P<0.05). Results of the study indicates ginger as a potential plant based amylase and glucosidase inhibitor in carbohydrate digestion but usage in glycaemic control in human has to be investigated further.

Crossing Bowen Street : mapping interventions in the classed subject

Synopsis: Crossing Bowen Street Crossing Bowen Street is an extended novel set in Melbourne, Australia. The protagonist, Meg Flanagan, is accepted to teachers' college. Meg is 24 years old and has worked, and lived out of home, since 17. Having completed her year 12 studies part time while working, she has applied to the Melbourne State College for a Bachelor of Education. Melbourne State College is subsequently 'amalgamated'A into Philip University, the original 19th century sandstone institution which borders MSC. Meg has worked as a medical secretary prior to commencing her studies. An only child, she is the first member of her family to go to university, indeed to finish high school. Tertiary study is exciting for Meg and the novel explores the psychic journey as well as the intellectual one, as Meg experiences challenges to the possibilities for her life and the trajectory along which she once assumed it would flow. The narrative is told through episodic and epistolary forms, with particular periods in Meg's cultural and academic life forming the focus, picking up the integral elements of her journey and examining the psychic context and action. Characters in the undergraduate chapters of the novel are somewhat transient, although very important to Meg's rapidly developing, changing sense of herself. The constant 'trying out' of ways of being and even lifestyles sees Meg losing old 'friendships' and making new, even temporary, ones all the time. This allows the opportunity for Meg to explore her feelings about connecting to others and the nature of her relationships. The Meg reflected back to her by others is of constant interest to her, particularly as she is frequently reminded that others see a very different Meg than she does. The novel commences at the outset of Meg's tertiary career, as she initially articulates the extent of her aspiration, of her sense of the possibility of her own life. Each vignette deals, chronologically, with an aspect of Meg's expanding sense of possibility, socially, emotionally, intellectually. Certain vignettes explore her relations with friends and acquaintances in the course, which in turn provide A In 1988, Federal Labor Minister for Education John Dawkins, devised a plan to end the streaming of Australian tertiary institutions and created what is called the Unified National System. This meant that colleges of advanced education and institutes of technology were either created universities in their own right, or more commonly, merged with an appropriate existing university. This process allows a fascinating insight into the class dimensions of hierarchies and stratifications. The need of universities and their members for status has been profoundly underscored. the background and context for her sexual relationships. That aspect of her developing subjectivity provides a marked contrast, which Meg uses as leverage, when set against her sense of herself as a scholar and her growing notion of entitlement, which allows her to 'choose', where previously she believed she had no choice; the choice is a scholarly career. Within all this, Meg discovers and is deeply empowered by certain political left, and feminist, discourses within the university community. She is equally dismayed and alienated by other feminist practices; her growing engagement with her own agency sees her quickly abandoning feminist subject positions previously dear to her, which served a particular purpose and are now superseded. This notion of feeling betrayed by the promise of a value system (or rather, its practitioners) will recur throughout the action of the novel, as Meg moves into an academic role, first as doctoral student and then as academic, seeking to live her values as practice and to remain true to what her trajectory has taught her. This is crystallised in the novel as the role played by the place she came from, and how that informs, and complicates, who she becomes. The novel seeks to explore the fundamental contradictions in doing so, through Meg's increasing awareness that the academy is not the harmonious, class aware institution she has idealised, but a world driven by status and hierarchies. This realisation must be reconciled in the light of Meg's anxieties about her working-class background. Meg's doctoral training at an elite university underscores her developing sense of what constitutes excellence and the role played by highly influential conservative institutions in maintaining social arrangements. As her academic career unfolds, the holding of a Cambridge PhD allows Meg opportunities to make change as certain privileges are afforded her by virtue of her Cambridge status. Yet it is this very notion that she seeks to challenge. Her growing passion for the State University of Victoria, an institution developed for the education of working-class people, informs her activism within the academy. Why are excellence and equity polarised? Why does the institution matter more than the scholarship? Why is so much practice within universities contrary to the values scholars often claim? These questions are explored through the dynamics of academic working life as student and later as a teacher at a university with an explicit equity agenda. The Start of the End (2003): The action commences on a late Friday after at SUV, when the Department of Communication & Cultural Studies has just been advised of Meg's promotion to Associate Professor. This vignette sees the initial soiree and celebrations and allows Meg to reflect on her experience. As her colleagues and friends are congratulating her, a particular student comes looking for Meg. It is clear that Angela Watson needs course advice particularly from Meg. Their discussion seems a straightforward one on the face of it, but it underscores many things; that Meg has come the full circle in her academic life, and what it is that her journey has really been about. The route to professorial appointment is considered, as is the source of Meg's greatest professional joy and fulfillment; is it scholarship, followed by leadership, in her discipline? It is knowing she has continued to speak and act to change the life chances of all students, wherever possible? Or is it the subtle distilling of both of these, along with the knowledge which emerges from the nexus of teaching and research. That scholarship, new knowledge, surely must be taking us somewhere specific in relation to others? The more we know, the more we can do...to what end? From this reflection, we see the action of the novel unfold. We return to this scene at the end of the novel, as Meg considers the trajectory of her life and its themes in her work. The novel ends as she is faced with the next challenge. Arrival (1989): Acceptance sees Meg as she is attempting to transform her life and create a new one. She has just been advised of her admission to an undergraduate Bachelor of Education program, at the major Melbourne teachers' college. Meg shares her rented home with her high school best friend, Anna, and her fiance, Jason, who appears to be superfluous in her life. Meg is aware he is a partner for who she used to be. We see Meg in her job as a medical secretary and this allows the mapping of Meg's sense of her own world, as she travels between home and work. This first stage of seeking her aspiration- to be an English teacher-evolves. As Meg considers the meaning of what she is about to do and how she knows it is right. This involves a consideration of what work means in our lives and how this is different for jobs according to how they are classed. Her relationship with the life she has known, the person she has been, is changing and this change is represented through her relationship with Jason. Meg's first day at teachers' college demonstrates that she is in a constant, often painful, dialogue with herself. The difficulties she encounters in making sense of the relation between her two 'lives' are thrown into sharp relief. The preparation for college sees Meg interrogating herself about how she can be different. Her initial experiences at the College resonate with her highest expectations of the life that awaits her, of the multiple possibilities currently being authored for her. Her first attendance at classes offers the opportunity to try out some of those possibilities, to test them against those she meets and to map the ways she could discover to 'be'. There is much tension and fear, but also endless excitement and these conflicting emotional states parallel and marble each other. It is on this day that she meets Jennifer Wren, her first real friend at university, who offers so many challenges to Meg. Their friendship involves a constant exhausting shift of subject positions, which Meg is able to look back on with affection in years to come. Going Bowling (1989): within a few weeks of commencing at university, Meg is socializing with some of her new friends, having neatly segmented her home and college lives. Meg has already realised that her friendships fall into separate groups; her friendship with Jennifer and the people Jennifer knows does not find its way into this group. They meet in the city to go bowling and have a meal. While Meg really enjoys these new people, already tensions are developing in relations between the group. Their unofficial leader, Rosemary Marshall, has a tendency to seek control and already resistance is showing. Rosemary particularly does not like Jennifer. Meg is enjoying her flirtation with Pete Danville, whom she has assumed to be gay. His very flattering attention has already developed Meg's confidence and stoked her ego, which has eroded in her stagnating relationship with Jason. Rosie has developed a crush on Pete and seems to take the flirtation with Meg personally. Dynamics in the group become slightly uncomfortable but Meg has grown quickly fond of her new friends, especially flamboyant Marina, another whom Rosemary seems to dislike. The discussions which occur during their evening deepen both the relationships and the tensions between them and draw lines which will determine the outcome of their various friendships. The Ball (1990): In the third year of her degree, much has happened to Meg. She is married to Jason, although she omits him from much of her psychic (and practical) life. Meg and her friends attend the Faculty's annual formal dinner dance. Meg has so far managed to balance the competitiveness which occurs between all of them, both academically and personally. The negotiation of her respective friendships with Jennifer and Marina requires a great deal of diplomacy; the subtext in this is very disturbing to Meg. What exactly is the conflict about? She can't be sure why they don't like each other; it could be Marina's smoking, or Jennifer's confidence to spare, but these things also annoy her, yet she does not fight with either girl as they do with each other. Rose has always insisted that the problem is Jennifer's private school background, but Marina went to a catholic girls' school, so what could the difference be? The ball is initially a happy occasion; the girls dress up and they dance and drink champagne together with the boys. But dynamics operating beneath the surface force their way up. Rosie is ready to force Pete to confront her continuing crush on him; Pete confronts Meg about their ongoing flirtation. Meg gives in and admits to herself for the first time that she does want to be with Pete. He is grown up and exciting and strong. He offers her something she has never had with Jason. Married less than a year, she pushes her husband out of her thoughts. The events of the ball force Meg to confront the differences between all her friends and the discomfort this affords everyone. Rosie's continued need for control over the group is acknowledged. Future Present (1991): Meg lives in Carlton with Pete. This is the busiest year thus far in her academic career and the financial, academic and emotional pressure is showing. This vignette gives us the range of Meg's academic activities and the way her life has fallen since the events at the ball eight months earlier. We see Meg grappling with her own evaluation of the changes in her 'way of being'; trying on different ways of living that she has idealised and finding them just as wanting as the last. Meg faces some key existential questions in this vignette and seeks answers which she finally discovers only she can give. Her relationship with Pete, the values and goals they share (and don't share) are thrown into sharp relief and provide a touchstone for the clearer determination of Meg's aspiration and future. Her relationship with various female friends is also revisited and this offers insight into Meg's constant checking of herself against idealised female templates. There is a crisis of identity and strength which constitutes an important fork in Meg's road. Beyond (1992): Beyond sees Meg determinedly seeking ways she can progress towards her goal, while still constantly checking against herself that postgraduate study (let alone a scholarly life) is available to her. We accompany Meg as she seeks and locates the academic path she wants; this is the backdrop for her further psychic exploration of the women who intimidate yet fascinate her, particularly Heloise Waul, who is a significant influence through Meg's postgraduate career. The sites in which Meg's personal struggles manifest are highlighted in this vignette, particularly in terms of dress and cultural pursuit. The conversations between Meg and Heloise also allow an exploration of the feminist politics of that milieu and the class tensions which operate tacitly within those politics. Bound to the Caucus (1992); Meg has now nearly completed her undergraduate degree and has been active for some time in university life and student politics. Her feminist and socialist education is well advanced. Bound to the Caucus shows us Meg in her student politics world for the first time, where the segue of her activism and academic life have taken her. Meg has found female friends who understand that part of her which struggles with inadequacy, although at this point in the novel this common struggle is not well understood or articulated. It is in this vignette that Meg admits her growing attraction for a Liberal student activist, Stuart Noble; this proscribed liaison raises many questions about values and aspiration, as well as the dominant sexual politics of the time and place. Bound to the Caucus also offers insight into the student activism occurring at universities like Philip in the early 1990s. Divergence (1993): Set in 1993, Meg is now in the early weeks of her honours program, although she has been at work on her thesis on the poet William Blake for some months. Living unhappily in a share household near the University, her relationship with Stuart Noble continues to develop, reaching a crisis point in this period. These events occur in the context of Meg's activist career in the Student Left, particularly as she encounters issues of identity around her class, feminism and difference amongst Left women. While Meg fights these battles passionately in an intense milieu, she considers them emotionally in terms of her changing sense of herself. Meg is increasingly aware that the personal impact of her class is changing for her. Additionally, she explores her relation with a 'boyfriend' of right wing political affiliation; Meg comes to recognise that this relationship is undermining her sense of herself in a way that her relationships with women in the left previously did. Honour Roll (1993): Meg is now undertaking honours and this vignette opens with Meg seeing the honours coordinator, Professor Michaela Moore, who approximates all those apparently middle-class traits to which Meg has such a push-pull relation. We see the return of a chapter of the honours thesis, discussion of the content and the constantly shifting subject positions these experiences offer Meg. This vignette also directly introduces Agnes. Mia and Agnes meet Meg after her supervision and this conversation allows very distinct if tacit class themes to develop. Meg has warmed quickly to Agnes, who is unlike anyone she has known; they have much in common in relation to their work and this binds them. Mia continually presents a viewpoint which irritates Meg, in relation to entitlement: to academic life, to funding, even to questioning how these things are enabled. Honour Roll allows us to see Meg's flourishing theoretical and intellectual life and its role in assisting her emotionally as she re-frames the same conundrums that previously constituted obstacles. The Cusp (1993): Meg's developing friendship with Agnes offers her enormous insights into difference and her developing sense of self and aspiration. While the girls come from diametrical backgrounds, they are united by their passion for their research and scholarly work. Meg is increasingly self-conscious through their discussions in terms of how she has seen herself and allowed herself to dream and seek. Cusp is set at the end of the honours year, prior to the release of results. Meg and Agnes explore their feelings about academia and this leads to discussions of purpose and the role of class within that. This vignette also documents Meg's growing social confidence and those aspects of herself which have become so sure to her, that she no longer considers them at all. Whom (1996): [Not included in this abridged edition]. Set at Cambridge, two thirds into Meg's doctorate, Whom shows Meg in the mental space which will take her back to Melbourne and the State University of Victoria. Having risen to the challenge of doctoral study, she is confronted now by deeper demons, and the need to explore and challenge them in the ambivalent context of Cambridge, which so excites her still, but which has proved empty of the profoundly held higher ideals she expected to see reflected. Set in the midst of Meg's doctoral study, this vignette is dramatically abridged in the submission novel. The importance of Whom lies in its concern with Meg's rapidly shifting sense of herself and her own scholarly subjectivity and the changes to these that the culture of Cambridge has wrought. By the second year of her PhD Meg is crystal clear about her goals and decides to spend the long break at home, rather than travelling, because she wishes to 'touch base' with her future. The action described segues into that in Courting the Enemy. Whom describes Meg's ambivalent and contradictory but passionate feelings about Cambridge. Whom demonstrates Meg's increasing anger at the status and privilege to which her education now automatically admits her, and her need to find some sort of stasis and safety in her emotional life. In this vignette, Meg meets her life partner, Jeremy McCallum (I have intentionally reduced the attention in the novel to Meg's romantic life as she matures into her career). Courting the Enemy (late 1990s): By this time, Meg is a senior lecturer in English at the State University of Victoria, which was established in the nineteenth century as the Worker's College. This vignette starts with Meg's attendance at a University Committee which is considering a transformation in relation to equity in admissions policy. Meg was drawn to SUV because of its transparent and determined commitment to educate the children of working-class people. An attack on the equity admission policy of her university galvanizes Meg and some of her colleagues. The action of the vignette considers the role of the scholar, and of such an institution as SUV, in the light of daily academic life. This vignette is primary in its demonstration of the themes of the novel. In the unabridged version, I took the opportunity to illustrate some of the vast range of administrative, intellectual and even physical demands on a senior scholar in the routine of academic life. In placing Meg in this context, I sought to highlight how a scholar of her values and commitment makes sense of the constantly shifting terrain of her working world and how this continually informs her practice. This vignette is also significant for its retrospective description of Meg's employment at SUV some years earlier. Locus: (1995). This piece of writing stands apart from the rest of the novel. I wished to write in a reflective voice, which might be from Meg's journal, were it not in the (omniscient) third person, in order to consider the headspace and meaning-making which occurs as Meg settles into Cambridge, and the lifestyle her situation allows her. Locus is a deeper engagement with Meg's sense of her identity. It considers the impact on her of the physical journeys she must make to match those of her psyche. These are thoughts too personal for a letter, even to Anna. Meg is exploring her ever shifting self and the growth in her self-belief allows her to explore what is rage; that she was bounded by illusions about her worth. Locus seeks to allow some context for Meg's anger at the role Cambridge plays. I seek to create the space in which Meg's dawning self understanding will lead her to her next, driven, purpose. Letters: throughout the novel letters are used to reveal and inform Meg's relationship with her family. This is an intentional device to distance the birth family in an attempt to blur and muddy an assessment of Meg's class through traditional measures. The letters between Meg and Aunty Jean particularly reveal much of the classed emotional antecedents of Meg's life. There are also letters exchanged with Meg's high school best friend, Anna, who has moved to the country and a very different lifestyle. Meg writes to Anna often, using the acceptance she feels in the friendship and her sense that Anna understands her, to touchstone her own emotional growth. Formal letters from institutions ring changes in settings and mark significant points in the geographical and academic trajectory of the character. All the letters serve to introduce time and event changes consistent with the episodic style of the narrative.

Interaction of dietary fibre, carbohydrate metabolism and diabetes in the rat

It is currently accepted that the most appropriate diet in the treatment of non-insulin-dependent diabetes mellitus "e;NIDDM"e; is high in carbohydrates, high in fibre and low in fat. Dietary fibre reduces the rate of carbohydrate absorption, which may have a beneficial effect on insulin action. Furthermore, high fibre diets also increase the amount of carbohydrates which are not absorbed from the small intestine. These malabsorbed carbohydrates are fermented by the bacterial population in the large intestine, producing short chain fatty acids "e;SCFA"e;, including propionate, which has been shown to alter liver carbohydrate metabolism. This thesis investigated the actions of slowed carbohydrate absorption and carbohydrate malabsorption in streptozotocin-induced "e;STZ"e; diabetic rats. High carbohydrate diet supplemented with guar gum, a soluble dietary fibre, fed to STZ diabetic rats improved insulin sensitivity. investigation of the alterations in the stomach and small intestine demonstrated that guar increased the viscosity of the meal in the intestine. The action of increased fermentation, producing more propionate, was investigated by supplementing propionate into the diets of STZ diabetic rats or when perfused into isolated rat livers. No changes in insulin action or liver glucose metabolism were measured. in addition, it was shown that guar gum reduces food intake in STZ diabetic rats. Mild reductions in food intake in STZ diabetic rats were shown to increase insulin action. In summary, STZ diabetic rats fed high carbohydrate, high fibre diets reductions in food consumption and slowed carbohydrate absorption are important factors which may lower blood glucose concentrations and increase insulin action. increased SCFA production is unlikely to contribute significantly to the improvements in insulin action.

Nutrition, growth and production of Cherax Destructor Clark, 1936 (Decapoda, Parastacidae)

In this study the nutrition, growth and production of C. destructor was examined. Selected nutritional requirements of juvenile animals were determined under controlled conditions with the aim of developing a pelleted diet for use in hatcheries, nurseries and growout situations. The best developed diet was assessed for its potential as a supplementary feed for animals cultured in earthen environments. The protein requirements were first determined simultaneously with an evaluation of the effect of replacing animal protein (fishmeal) by soybean meal. Juveniles were reared communally for 59 d on isoenergetic diets containing 15-30% protein and graded levels of soybean meal (0-60%, of protein). When soybean meal was included at a level of 40-60%, growth was reduced relative to that achieved with control diets containing 15% and 20% protein, but this was not the case at a 20% soybean meal substitution level. A two-way interaction occurred between dietary protein and soybean meal content. Higher protein feeds enabled higher soybean meal inclusion levels without significantly affecting growth. Protein increases of 5% produced better growth at the 40% and 60% soybean meal substitution levels. This effect was less pronounced in the control and the 20% soybean meal diets. Carcass %protein increased and %lipid decreased as dietary protein increased. A similar effect occurred by increasing the soybean meal level to 60%. No obvious trend in carcass moisture, energy, and ash occurred. A protein requirement of 30% was apparent when fish meal and soybean meal were included in diets at levels of 20% and 24% (dry matter) respectively. Alternative protein sources to soybean meal were subsequently identified. Juveniles were maintained for 12 weeks on isoenergetic diets containing 30% protein and differing in the primary source of protein used, with meat, snail, soybean, yabby, and zooplankton meals comprising the major protein ingredient. No significant difference occurred in mean weight (MW), percentage weight gain (%WG), SGR or survival among diets. Food conversion ratios (FCR) were low, with a minimum value of 0.95 for the snail-based diet. The apparent net protein utilisation (ANPU) varied from 29.6% (zooplankton-based diet) to 41.2% (snail-based diet). Carcass composition varied with diet, with the greatest difference occurring in carapace colour. Animals fed the zooplankton-based diet developed the strongest, most natural pigmentation. A new combination of previously used protein-based ingredients was subsequently tested with reference to two yabby species, Cherax albidus and Cherax destructor, that were grown simultaneously in identical conditions. Juvenile male animals were reared individually for 20 weeks on isoenergetic diets containing 15% or 30% protein with fish meal, soybean meal, yabby meal and wheat products forming the basis of the diets. C albidus grew the fastest and utilised the food the most effectively. Carcass composition was influenced by diet with the 30% protein diet resulting in an increase in carcass protein and ash and a decrease in carcass lipid and energy relative to the low protein diet. Carcass moisture and calcium were not affected by diet. The intermoult period (IP) was highly dependent on the premoult weight (W) but the mean moult increment (WI, as weight) was independent of the PM. The orbital carapace length (OCL) and the abdominal length (ABL) %moult increments generally declined with an increase in PM whereas the propus length (PL) %moult increment generally increased. The IP, WI, %OCL, %ABL, and %PL moult increments varied according to diet and to species. Elevated dietary protein caused a reduction to the IP (for similar sized animals) by 11 d and 7 d and an increase to the WI by 85% and 81% in C. albidus and C destructor respectively. Dietary induced morphological changes also occurred. Animals of a standard OCL (both species) had significantly larger abdomens when fed the higher protein diet. Growth on the best developed diet was compared to the growth obtained on a natural diet of freshwater zooplankton. Juveniles were reared individually for 12 weeks on the two diets. The MW, %WG and SGR were higher for the zooplankton diet. Carcass composition was influenced by diet and the zooplankton fed animals had a higher carcass %protein, %lipid, %ash and %fibre content and were more richly pigmented than animals fed pellets. The IP and the WI were highly dependent on the PM and varied according to diet; feeding with zooplankton reduced the IP by 1.2 days and increased the WI by 13.7% compared to pellets. Nutrient digestibility was determined for the pelleted diets evaluated in the growth trials. Protein digestibility (PD) and dry matter digestibility (DMD), using chromic oxide (Cr2O3) as an exogenous marker, were high for all diets, at around 93% and 83% respectively. Ash digestibility varied considerably from 17% to 73% for the snail and yabby meal diets respectively. Crude fibre digestibility was around 50% and probably indicates cellulase activity. Alternative markers to Cr2O3 were evaluated. Ash was considered to be the most suitable alternative to Cr2O3, providing a reasonable, albeit lower, estimate of nutrient digestibility. Cr2O3 and ash were preferentially excreted whereas fibre was retained in the digestive system for a longer period, consequently, the collection of a particular fraction of the deposited faeces (late or early) substantially affected the digestibility coefficients. In earthen-based environments, animals fed the best developed diet were compared to animals cultured using a forage crop of clover (Trifolium repens). Three supplementary feeding strategies representing varying levels of management intensity were evaluated in a series of trials conducted in ponds and pond microcosms. Growth on pellets consistently exceeded that obtained with the forage crop, with final MW being 67-159% higher than that using clover and appeared to be the result of direct pellet consumption and from a pellet fertiliser effect (on the sediment). Within-pond DMD and PD were high and similar for each treatment (DMD = 51-58%; PD = 89-92%). In the control pond, DMD and PD increased with each successive flood. The faecal egestion rate (PER) decreased with each successive flood in all ponds, and is negatively related to animal weight and to foregut fullness (FF) according to power curves. FF was consistently lowest in the control pond. Mean FF was 48.5%, 62.3%, and 26.7% for the pellet, crop and control ponds respectively. FF increased to the third flood in each pond. The foregut protein content was high in all samples and the mean values were 33.9%, 32.7% and 35.6% for the pellet, crop and control ponds respectively. Foregut ash was highly variable within each pond and is inversely related to the foregut protein content. In the control and pellet ponds the highest foregut ash content occurred during flood 1. The culture system (aquaria or pond) strongly influenced the composition of the foregut content. The foregut of animals fed the manufactured diet (B2) in ponds contained approximately 176% more ash and 5% more protein than the foregut of animals fed in bare-bottom tanks. The FF of the tank fed animals was approximately 45% higher than the FF of pond fed animals after a similar feeding period. Base-line yields for extensive production systems appeared to be around 400kg ha-1. The supplementary addition of T. repens produced yields of approximately 635kg ha-1 (in ponds) to around 1086kg ha-1 (in tanks). The sequential addition of cut-clover to tanks stimulated growth to levels approaching those achieved on pellets. Yabbies stocked into ponds at 15-20 m-2 with a mean weight of 2.67g and fed a 30% protein pelleted diet for 100 d, resulted in a yield of approximately 1117kg ha-1, but only 2% of the population were above a marketable size of 50g. The feed utilisation indices were better for animals reared on pellets in bare-bottom tanks than in earthen environments, indicating some degree of pellet wastage when natural feeds are simultaneously present. High apparent food conversion ratios and low protein efficiency ratios occurred when the forage crop was provided. A considerable quantity of the dry matter and protein content of the forage crop was either inefficiently utilised or directed into other production pathways. Sowing a forage crop into pond microcosms to which a pelleted diet was also provided, did not enhance growth performance. Pelleted feed inputs at a rate of approximately 129g m-2 to 198g m-2 (dry matter) and 38g -2 to 64g m-2 (protein) over 70-100 d resulted in acceptable growth and feed utilisation indices for animals reared in ponds and pond microcosms. Forage crop inputs of approximately 533g m-2 to 680g m-2 (as dry matter) or 84g m-2 to 177g m-2 (as protein) over a 70-100 d period produced reasonable growth rates but poor feed utilisation indices. Low inputs of dry matter (from 113-296g m-2) and protein (from 24-54g m-2) from clover were sufficient to maintain high growth rates in pond microcosms for around 28 d. In ponds, a very low level of 21g m-2 (dry matter) and 4.3g m-2 (protein) was sufficient for around 3 weeks. Forage depletion appeared to occur beyond week 3-4 and was probably a major growth limiting factor. The mean hepatosomatic index (HSI) was 9.44, 7.68, and 6.79 for the pellet, crop, and control ponds respectively. The relationship between hepatopancreas weight and overall animal weight was significantly different between treatments. The hepatopancreas of pellet-fed animals had the highest %lipid and lowest %ash, %protein, %carbohydrate and %moisture content. In terms of absolute quantities, the only major difference in hepatopancreas composition between treatments occurred for lipid and dry matter content. The hepatopancreas of the pellet-fed animals was a cream/cream-yellow colour and was very fragile, whereas in the other ponds it was a more ‘natural’ bright yellow colour and was structurally more robust. C. destructor has a capacious foregut, being approximately 5 times the volume of similar sized Penaeids. The foregut volume (V, ml) of the yabby is related to animal weight (W, g) according to V = 0.048 W0.9543. Animals that were starved for 96 h and then fed diet B2 were almost completely foil after 30 min. The ‘apparent enzymatic response’ of animals fed various natural and artificial diets in tanks was evaluated. Nutrient processing time and the enzymatic response following ingestion appeared to be regulated by the chemical and physical properties of the diet. For the natural feeds, foregut protein was 1.2% higher (for zooplankton) and up to 300% higher (for detritus) than dietary protein, whereas ash was 7.5% higher (zooplankton) and 46-63% lower (detritus) than dietary ash. For animals fed diet B2 after 48 h without food, FF was approximately half that of 96 h starved animals after a similar feeding period but foregut protein and ash contents were similar. Finally, the physiological and morphological attributes elucidated in this study are discussed with reference to the ecology of the yabby. High growth rates, excellent feed utilisation indices and high digestibility coefficients for a wide range of diet-types illustrate nutritional flexibility. A capacious foregut, a large hepatopancreas with a high energy storage capacity, the ability to partition and preferentially excrete the low nutrient value inorganic component of the diet, the capacity to alter body form, nutrient processing time and enzymatic secretions in relation to diet-type, and modified behaviour according to feed availability also demonstrate plasticity/adaptability/flexibility. The combined effect of these important characteristics ensures survival in environments that may be adverse and highly variable in terms of nutrient availability. Collectively the morphological and digestive traits elucidated in this study reflect the generalist-type nature of C destructor and indicate that a polytrophic classification still seems appropriate. Several priority areas for further nutrition research are identified and recommendations are made regarding the best-practices to use in the commercial culture of the yabby. Of paramount importance is the further clarification of the nutritional requirements and feeding preferences of animals in various phases of development.

Determination of human body composition

This thesis deals with two electrical methods designed to enable rapid, safe and noninvasive measurement of body composition, both for clinical and community use. The first section provides a review of the literature related to measurement of body composition in humans and outlines the approach of the research project. The second section deals with established methods of determining body composition, the two most important being hydrostatic densitometry and deuterium oxide dilution. In this part of the report, a novel method for measuring lung volume by hydrogen dilution at the time of underwater weighing is described. The main findings of the thesis are contained in the third section which deals with the assessment of body opposition by electrical means. There are two components to this part of the study. The first involved the testing of a commercially available bioelectric impedance analyser (BIA) which measures impedance to a flow of current through the body. Studies on the reproducibility and reliability of measurements were performed. Results showed the importance of correct electrode placement and revealed that subjects can consume a light meal and a drink before being measured with the BIA without adversely affecting impedance readings. Results suggested, however, that subjects empty their bladders before measurements are made. Strong correlations were found between height 2/ resistance and measurements of total body water (r = 0.839) and fat-free weight derived from densitometry (r = 0.821), Moderate correlations (r = 0.6 to 0.7) were also found when height /resistance was related to fat-free weight derived from anthropometric measurements. The second and major consonant of the third section deals with the development of a method based on the absorption of energy from a weak electromagnetic field established in a capacitor or chamber large enough to accommodate an adult human subject. The method involves measurement of the effect of the body on the electromagnetic field, and is based on differential absorption of energy by body fat and fat-free tissues. Regression equations were developed for predicting the weight of fat and fat-free tissue in the body from measurement of electromagnetic field effects in a test capacitor and in a resonating chamber. The test capacitor comprised a large aluminum cylinder with a copper rod as a central conductor. The following equation was derived for the relationship of fat-free weight (FEW) based on body density, with measurements of change in resonant frequency (ΔfR), height (H) and weight (W) : FFW = -4.39 + 0.690 W + 19.9 H + 37.6 ΔfR In a study of 17 subjects, a value of 0.891 was found for R2, and S.E.E. was 1.63. The resonating chamber consisted of a large enclosed aluminium cylinder with a copper rod as a central conductor. The following equation was derived for the relationship of fat weight (FW) based on the mean of estimates from body density and total body water, with measurements of change in signal attenuation (ΔA), change in resonant frequency (ΔfR), and height (H) and weight (W) : FW = 73.48 + 0.291 (W/√(ΔA) - 49.2 H - 0.53 ΔfR In a study of 27 subjects, a value of 0.956 was found for R2, and S.E.E. was 1.97. In these equations, variables were measured in the following units : FEW, FW and W (kg), ΔfR (MHz) and H (m).