1,481 research outputs found
Metabolism of some gluconeogenic substrates in sheep during exercise
No full textSheep can exercise for long periods, during which blood glucose is utilised at an increased rate by working muscle (Pethick et al. 1987). The liver must therefore increase its rate of glucose secretion. This paper presents results to show the potential significance of several gluconeogenic precursors.n
The Physiology of marbling: What is it, and why does it develop
No full textThis review describes our current understanding of the factors affecting growth and development of adipocytes in bovine skeletal muscle and discusses alternative hypotheses to explain intramuscular fat deposition: marbling. While genetic predisposition clearly plays a role in the development of this commercially interesting phenotype, animal age, energy nutrition, vitamin nutrition, compensatory growth and previous growth rate may also contribute to the final outcome. The review briefly analyses the data supporting each hypothesis and attempts a mechanistic description based on the development of tissue precursor cells into mature adipocytes. Properties of the mature adipocyte in the context of whole animal and muscle biochemistry are discussed in the companion paper by Pethick et al. (2001)
Growth, development and nutritional development of marbling in cattle
No full textThis review discusses our current understanding of the growth and development of intramuscular fat and proposes a simple growth model to explain the accumulation of intramuscular fat in cattle. Potential effects of nutritional manipulation are discussed in relation to the proposed growth curve for intramuscular fat. The scope for nutritional control during both the pasture (or backgrounding) and intensive grain finishing phase are discussed. Additional discussion on nutritional triggers of the cellular and early life events associated with the development of the intramuscular fat are discussed in the companion paper by Harper and Pethick (2001)
Increasing the viscosity of the intestinal contents stimulates proliferation of enterotoxigenic Escherichia coli and Brachyspira pilosicoli in weaner pigs
No full textThe present study was designed to evaluate the effect of increased viscosity of the intestinal digesta on proliferation of enterotoxigenic Escherichia coli and the intestinal spirochaete Brachyspira pilosicoli in weaned pigs. Pigs were fed an experimental diet based on cooked white rice (R), which was supplemented with carboxymethylcellulose (CMC; 40 g/kg diet) to increase digesta viscosity. Thirty-six piglets weaned at 21 d of age were divided into six groups, three of which were fed R and three R + CMC. Addition of CMC increased digesta viscosity in the ileum (P=0.01), caecum (P=0.0007) and colon (P=0.0035), without increasing indices of large intestinal fermentation. Pigs fed R + CMC developed a natural infection with enterotoxigenic E. coli after weaning and had more (P<0.0001) diarrhoea than pigs fed R. Subsequent experimental infection of two groups of pigs with B. pilosicoli resulted in more (P<0.0001) colonisation in pigs fed R + CMC than R. At this time, all pigs fed R + CMC had wetter (P<0.0001) faeces than those fed R, irrespective of whether they were infected with B. pilosicoli, but infected pigs also had an increased (P=0.025) number of days with diarrhoea post-infection irrespective of diet. In pigs fed R + CMC, it was not clear to what extent the increased viscosity associated with CMC, or the concurrent infection with enterotoxigenic E. coli, was responsible for the increased proliferation of B. pilosicoli. In a second experiment, five pigs that were weaned onto an R diet were transferred onto R + CMC 3 weeks later. These pigs did not develop a natural infection with enterotoxigenic E. coli after the diet change, confirming the particular susceptibility of pigs to enterotoxigenic E. coli proliferation immediately post-weaning
Pigs experimentally infected with Serpulina hyodysenteriae can be protected from developing swine dysentery by feeding them a highly digestible diet
No full textWeaner pigs (n = 72) were fed 1 of 4 diets. These were based on either cooked rice and animal protein, cooked rice and lupin, wheat and lupin, or wheat and animal protein. Twenty-six of the pigs were slaughtered after 1 month. Those fed the highly digestible cooked rice and animal protein diet had drier colonic contents and faeces, lighter large intestines, and the contents of their large intestines had increased pH values and decreased total VFA concentrations. The other 46 pigs were orally challenged with broth cultures of Serpulina hyodysenteriae, and were monitored for faecal excretion of the spirochaetes, and for the development of swine dysentery (SD). None of 18 pigs fed the cooked rice and animal protein diet developed colonic changes or disease, whereas most pigs on the other diets developed mucohaemorrhagic colitis and dysentery. The reduced fermentation that occurred in the large intestines of pigs fed cooked rice and animal protein was associated with a subsequent failure of colonization by S. hyodysenteriae, and resultant protection against SD
The importance of Lean Meat Yield: The value it creates in the supply chain and the importance of better feedback to farmers
No full textLean meat yield is a key efficiency and profit driver throughout the supply chain. Lamb is sold in lower yielding formats at a retail level (ie more bone and fat) compared to beef, pork and chicken and is typically more expensive, especially when compared on a $/kg lean at retail (Pethick, Ball et al. 2010). High yielding carcases deliver cuts that have a better shape and ensure retailers do not have to present products of overly fat animals for display and sale. For processors a high yielding animal represents increased efficiency in the boning room. These carcases require less labour to trim fat and there is less carcase wastage. For producers, higher yielding animals can be finished to heavier weights without becoming overly fat and accruing penalties. Additionally, fast growing, high yielding animals can be finished either faster or to heavier weights, in a shorter period of time, offering the producer savings on feed costs.
The challenge is to produce a fast growing lamb that can be turned off quickly, that are of favourable conformation, and also gives a satisfactory return to the producer. It is increasingly important that price signals reflect not just more carcase as it may represent increasing amounts of fat. With continued evolution of the payment scheme of lamb there is the potential to improve profitability through the use of genetic selection for increased yield
Increasing digesta viscosity may increase parasite establishment in the small intestine of sheep
No full textStrongyle infections and diarrhoea are major problems for the sheep industry, but the nutritional factors determining faecal consistency and susceptibility to enteric diseases are not well understood. Soluble non-starch polysaccharides (sNSP) have been shown to affect the physico-chemical environment of the gut lumen, by increasing viscosity of digesta and affecting microbial fermentation in the large intestine; however, the role of sNSP in sheep has not been studied. sNSP have been shown to increase parasite establishment in the small intestine of mice (3) and decrease parasite establishment in the large intestine of pigs (2). Carboxymethylcellulose (CMC) is a non-fermentable viscous-forming agent that is used to study the effect of soluble NSP in increasing digesta viscosity independent of potential effects on fermentation (I). The aims of this study were to investigate whether increasing viscosity of digesta using CMC may affect establishment of Trichostrongylus colubriformis and Telodorsagio (Ostenagia) circumcincta in sheep and whether the type of roughage and CMC may affect faecal consistency in sheep with strongyle infections
Nutritional influences on some major enteric bacterial diseases of pig
No full textThere are several enteric bacterial diseases and conditions of pigs that require control to prevent overt disease, to reduce morbidity and mortality, and to improve the efficiency of production. Traditionally, veterinarians, feed manufacturers and producers have relied upon antibiotics and minerals (for example, ZnO, CUSO4) in diets for a large part of this control. However, recent trends, particularly in Europe, are to reduce antimicrobial use and seek alternative or replacement strategies for controlling enteric bacterial diseases. The majority of these strategies rely on 'nutrition', taken in its broadest sense, to reduce the susceptibility of pigs to these diseases. Evidence to date suggests that specific dietary interventions, for example feeding very highly-digestible diets based on cooked white rice, can reduce the proliferation of a number of specific enteric bacterial infections, such as post-weaning colibacillosis. No simple and universal way to reduce susceptibility to pathogens in the gastrointestinal tract has been identified, and the underlying basis for many of the reported positive effects of 'nutrition' on controlling enteric infections lacks robust, scientific understanding. This makes it difficult to recommend dietary guidelines to prevent or reduce enteric bacterial diseases. Furthermore, some diseases, such as porcine intestinal spirochaetosis caused by Brachyspira pilosicoli, are sometimes associated with other pathogens (co-infections). In such cases, each pathogen might have different nutrient requirements, ecological niches and patterns of metabolism for which a variety of dietary interventions are needed to ameliorate the disease. Greater understanding of how 'nutrition' influences gut epithelial biology and immunobiology, and their interactions with both commensal and pathogenic bacteria, holds promise as a means of tackling enteric disease without antimicrobial. agents. In addition, it is important to consider the overall system (i.e. management, housing, welfare) of pig production in the context of controlling enteric bacterial diseases
Classification of sheep category using chemical analysis and statistical classification algorithms
No full textIn Australia, dentition (eruption of permanent incisors) is used as a proxy for age to define sheep meat quality. Lamb is defined as having no permanent incisors, hogget as having at least one incisor and mutton is defined as having two or more incisors. Classification of the carcase is done at the abattoir prior to the removal of an animal’s head. Recently, an Australian Senate inquiry into meat marketing reported that there was concern that substitution of hogget and mutton for lamb may be occurring in the industry. At present, no objective method is available that can be used for classifying sheep category. The general aims of this thesis were to i) evaluate whether chemical analysis of branched chain fatty acid (BCFA) content could be used as an objective tool to determine sheep age, ii) understand the effect that some production factors had on BCFA concentrations in Australian sheep and iii) develop new approaches (whether chemical and/or statistical) for determining sheep category (age).
BCFAs are implicated as the main contributors to “mutton flavour”, often associated with the cooked meat of older animals. BCFAs are reported to increase with age, which suggests that chemical analysis of these compounds could be used as an objective method. Concentrations of three BCFAs (4-methyloctanoic (MOA), 4-ethyloctanoic (EOA) and 4- methylnonanoic (MNA) acids) were measured in a survey of fat samples taken from 533 sheep carcases at abattoirs in New South Wales, Victoria and Western Australia. This thesis shows that, on its own, chemical analysis of the BCFAs is not sufficient to discriminate lamb from hogget and mutton as pre-slaughter nutrition is a significant factor in classifying sheep using this approach. Uncertainty at the BCFA concentration ranges found in Australian sheep was determined to be high making it difficult to discriminate between sheep carcases of different ages based on the BCFA level.
Fast gas chromatography was evaluated as the basis for a high throughput chemical technique but was not sufficiently sensitive for BCFA measurements. Solid-phase microextraction (SPME) was also found to be suitable for sampling 3-methylindole and p-cresol, compounds responsible for diet-related “pastoral flavour” in sheep fat, but further work is needed to validate this approach for measurement of these compounds in sheep fat.
Statistical classification algorithms, when applied to the chromatograms measured for the 533 carcasses, showed great promise for predicting sheep category. Specifically, the random forests algorithm, when applied to mean-centred data, gave 100% predictive accuracy when differentiating between lamb, hogget and mutton. This approach could be used for the development of an objective method for determining sheep age and category, suitable for use by the Australian sheep meat industry
Poe's biopics : representations of the author in D.W. Griffith's Edgar Allen Poe and James Mcteigue's The raven
No full textLiterary biopics often reinforce romantic images regarding the creative process, emphasizing biographic and author-centered approaches to literature previously denounced by Roland Barthes (1977). Curiously, one of the most famous critics of such romantic conceptions, Edgar Allan Poe, has himself been a victim of this very same treatment, his literary production being taken as part and result of his controversial biography in a number of works. This article analyzes two biographical films, or biopics, about the renowned poet, D.W. Griffith’s Edgar Allen Poe (sic) (1909) and James McTeigue’s The Raven (2012). The analysis of these works indicates that both reinforce the merge of the artist’s life and oeuvre, as well as the blurring of borders between fact and fiction, author and character, high and mass culture, thus contributing to the characterization of the biopic as a fitting example of historiographic metafiction. (Hutcheon, 1988).Cinebiografias literárias frequentemente reforçam visões românticas quanto ao fazer artístico, reiterando a visão biografista e a centralidade do autor há muito denunciadas por Roland Barthes (1977). Curiosamente, um dos mais célebres críticos de tais concepções românticas, Edgar Allan Poe, viu-se vítima desse mesmo tratamento ao ter sua produção literária apropriada como parte e reflexo de sua controversa biografia em diversas obras. O presente artigo debruça-se sobre dois filmes biográficos, ou biopics, acerca do célebre poeta, Edgar Allen Poe (sic), de D.W. Griffith (1909), e O Corvo, de James McTeigue (2012). A análise das obras aponta que ambas reiteram a fusão entre vida e obrado artista, bem como o apagamento das fronteiras entre fato histórico e ficção, entre autor e personagem, alta cultura e cultura de massa, contribuindo para a caracterização do gênero biopic como um dos mais bem-acabados exemplos de metaficção historiográfica (Hutcheon, 1988)
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