This thesis involves an investigation in three areas; first, a study of an enzymatic-gravimetric method for the analysis of dietary fibre; second, a survey of dietary fibre intake in an area of a developing country, and finally, some observations on the functional aspects of gel-forming dietary fibre in the rat. A simple and rapid enzymatic-gravimetric assay for both soluble and insoluble dietary fibre has been critically investigated. Reference samples were also analysed by a more comprehensive, enzymatic gas chromatographic method to allow testing of the relative accuracy of the enzymatic-gravimetric method. The enzymatic-gravimetric method was found to be highly reproducible but gave a slightly higher value for total dietary fibre than the more comprehensive method. This discrepancy is probably due to the presence of small quantities of resistant starch and protein residue which are recovered in the enzymatic-gravimetric method. In the enzymatic-gas chromatographic method, protein residue is not measured, and resistant starch is estimated, but not counted as dietary fibre. The enzymatic-gravimetric method was applied to the analysis of foods commonly consumed in the Padang region of West Sumatra in Indonesia, in order to estimate dietary fibre intake in the region. Daily intakes of usual foods were estimated by use of a 24-hour recall procedure aided by food photographs to assist in the estimation of portion size. Samples of approximately 60 of the most commonly consumed foods were collected and analysed for dietary fibre. These appear to be the first data which report values for dietary fibre in Indonesion foods and they represent a significant improvement upon the existing data on crude fibre content. Knowledge of the amounts of foods usually consumed and their dietary fibre content allowed an estimation of usual intakes of dietary fibre. Fibre intake was found to be lower than in the developing countries of Africa and was comparable to intakes measured in the U.K. This is the first study to show that in this part of South East Asia, a developing country area using polished rice as a staple food, dietary fibre intakes are as low as in Western countries. Low intakes of fibre are believed to be related to the prevalence of a range of diseases and, in this study, preliminary data on the rates of non-infective, chronic diseases were collected from the two main hospitals in West Sumatra. Chronic, non-infectious diseases such as inguinal hernia, appendicitis, haemorrhoids, diabetes mellitus, hypertension and malignant neoplasms of the rectum are relatively frequent in West Sumatra. While no firm conclusions can be drawn from these data, they do show the possibility of a relationship between low intakes of dietary fibre and the prevalence of these diseases, and suggest that further investigation is necessary. Some observations were made of the effect of gel-forming dietary fibre on stomach emptying and intestinal transit rate in the rat. Xanthan gum was added to iso-osmotic solutions to produce increased viscosity and phenol sulphonphthalein (phenol red) was used as a non-absorbable marker. Gavage feeding of solutions with a range of viscosities was used to study the effect of viscosity on the rate of stomach emptying and intestinal transit. Increased viscosity was observed to slow gastro-intestinal transit and this provides one mechanism by which dietary fibre of the gel-forming type ray improve glucose tolerance.

Optimal nutritional management of growing pigs is constrained by lack of quantitative information on the response of animals between 30 and 110 kg live weight to dietary energy content. Under 'ideal' conditions modern genotypes appear to adjust feed intake to maintain a constant DE intake over a much wider range of dietary energy concentrations than previously thought (Mullan et al, 1998). However, under commercial pen conditions, voluntary feed intake is lower, pigs respond in terms of both growth rate and feed conversion to dietary DE density considerably above the levels currently thought to maximise biological and economic responses. The present study was designed to provide information on the response of growing pigs to dietary energy content under ideal and commercial housing conditions for two growth periods 30-60kg liveweight and 60-100kg liveweight. The results of the pigs kept under individual (ideal) housed conditions were consistent with the literature in that they adjusted their voluntary feed intake with digestible energy density to maintain a constant energy intake. The results of the pigs kept in groups (commercial) housing conditions tended to increase their daily energy intake as the energy density of the feed increased. This increase in energy intake improved the growth rate of the pigs and increased the fat deposition of those pigs. Economic analysis of the experiments involving pigs in groups indicates that formulating diets to a least cost per megajoule of digestible energy is not the most profitable point to set the digestible energy density. Modelling programs need to be used to determine where the least cost per unit of growth of the pig occurs. This is the most economical digestible energy density to formulate too. This will have major impact on the cost of production of piggery operations as the cost of energy is the single most important parameter in the cost of producing a pig.

Stomach contents of 19 mature sperm whales, 18 males and one female, that stranded on New Zealand beaches between the mid 1990s and 2004 were examined, identified and measured. Three of the stomachs were empty. All other samples consisted almost entirely of cephalopod beaks. A total of 23,223 cephalopod beaks (10,647 upper and 12,576 lower), representing at least 36 species in 17 families were found in the remaining 16 stomachs. Non-cephalopod remains in the stomachs of sperm whales stranded in New Zealand included limited quantities of fish, salps, crustacean exoskeletons, a copepod, some wood and sand.The present investigation represents the most comprehensive study of the diet of sperm whales in New Zealand since the early 1960s. The results show that oceanic squid of the families Histioteuthidae, Cranchiidae, Onychoteuthidae and Octopoteuthidae are the most common remains found in the stomachs of sperm whales stranded on New Zealand beaches, with the families Onychoteuthidae, Histioteuthidae, Octopoteuthidae and Architeuthidae being the most important by estimated weight in whale diet, and the families Cranchiidae, Pholidoteuthidae and Ancistrocheiridae secondarily so.The beaks of three cephalopod species thought to be restricted to Antarctic waters (Kondakovia longimana, Mesonychoteuthis hamiltoni and Psychroteuthis glacialis) were found in 12 of the stomachs, suggesting these whales had recently migrated into New Zealand from more southern feeding grounds. The amount of local cephalopod beaks in the stomachs suggests some of the stranded sperm whales did not feed much within New Zealand waters in the days prior to stranding.The beaks of Taningia danae, Octopoteuthis megaptera, Octopoteuthis sp. 'Giant' and Lepidoteuthis grimaldii are illustrated and described. Oblique and lateral illustrations of the lower beaks are given, as well as sections of the rostrum, jaw angle, shoulder and lateral wall, to show the major identifying features for each of the species.Squid are an important component of food chains in the Southern Ocean and they act as both high-level predators and prey for apex predators. Therefore, seasonal fluctuations in their abundance must have cascading effects on the diets of apex predators. With increasing global fishing effort, and with cephalopods representing over 4% of the global annual catch, there are competing interests between the ocean's top teuthophagous predators and the fishing industry.Uncertainty of the effects fisheries have on the marine ecosystem has stimulated numerous research studies in recent years. However, despite the economic and ecological importance of cephalopods, there are few ecological studies on them or their significance in the trophic systems of the deep-sea and their life cycles and distribution patterns are only now beginning to be understood. Additional dietary studies that investigate the cephalopod composition and size-class structure in the diet of predators are needed to assess their importance in deepsea food webs, and the potential impact that deep-sea fisheries might have on associated and dependant species, namely apex oceanic predators.The results of this study provide the first significant insight into the diet of the sperm whale, one of the most important apex predators in New Zealand waters.

In recent years, dietary calcium intake among children and adolescents has fallen sharply. This trend is alarming because childhood and adolescence are the primary ages for building bone mass. Therefore, an interactive website, Clueless in the Mall (http://calcium.tamu.edu) was developed targeting youth to increase knowledge, improve attitudes, and equip them to incorporate calcium-rich foods into their diets. This website was created with the help of adolescents at every stage of development and has been pilot tested with adolescents at home and in school, showing improvements in knowledge and attitudes. However, the website has not been tested for effectiveness in changing behaviors, specifically for increasing calcium intake. The present study was conducted to measure the effectiveness of the website for changing knowledge, attitudes, and behaviors. The hypothesis of this investigation was that the website intervention would significantly improve attitudes and knowledge about calcium and increase dietary calcium intake among adolescents and pre-adolescents who took part in the study. After the group-administered Food Frequency Questionnaire (FFQ) was validated among a local church youth group, a total of 126 middle school and high school students were recruited from 12 local public school classes to participate. Each student took three questionnaires during class time to measure baseline knowledge, attitudes, and behaviors (including calcium intake using the FFQ). Then each student took one class period to view the calcium website. Four to six weeks later, the investigators returned to administer the same three tests to each student. Demographic information was collected, and data were analyzed using paired samples t-tests and analyses of variance (ANOVA). Results demonstrated that the website alone was sufficient to improve knowledge scores; however, it was not enough to change attitudes and behaviors significantly. In conclusion, the website should be used to promote and reinforce health behaviors, but should not be expected to stand alone as an intervention.

In the poultry industry, further processed meat products have the highest share in the market, and because there is a growing demand of food products with enriched amounts of unsaturated fatty acids, the objectives of this research were to assess lipid oxidation development and quality characteristics of chicken meat as affected by dietary fat and vitamin E levels. Broilers were fed during six weeks with diets containing animal/vegetable, lard, palm kernel, soybean, conjugated linoleic acid, flaxseed, or menhaden oil. Each lipid diet was supplemented with either a control (33 or 42 mg/kg) or a supranutritional level (200-400 or 200 mg/kg) of vitamin E. Breast and thigh meat, or skin, were processed, packaged, and refrigerated as raw meat, cooked patties, or cooked sous vide meat. The results showed that the chicken meat fatty acid composition reflected those from the dietary fats. In the meat or skin there was a higher lipid oxidation susceptibility as the proportion of unsaturated fatty acids increased, shown as malonaldehyde values, particularly in the treatments with low supplemented level of vitamin E (P<0.05). The relative lipid oxidative stability of the meat decreased in consecutive order from raw, cooked sous vide, and cooked meat patties. Sous vide cooked meat developed lipid oxidation at a slow rate and showed not to be affected by nonheme iron values. Dietary fat and vitamin E level affected breast meat lightness (L* color space) values (P<0.05), but not muscle pH, Allo-Kramer shear force, or water holding capacity. In conclusion, the increment in the proportion of unsaturated fatty acids increases the susceptibility to lipid oxidation in the meat. Supranutritional supplementation levels of vitamin E are more effective at inhibiting the lipid oxidation development in chicken meat than some current levels used by the poultry industry. Neither dietary fat nor vitamin E level seems to affect the development of pale, soft, and exudative meat condition in chicken meat.

The major objectives of this research were to examine the bioaccumulation parameters [depuration rates (kd), half life (t1/2) and biomagnification factor (BMF)] of individual isomers of hexabromocyclododecane (HBCD, C12H18Br6) in fish and to test the hypothesis of in vivo bioisomerization. This was done by exposing three groups of juvenile rainbow trout (Oncorhynchus Mykiss) to food fortified with known concentrations of an individual diastereoisomer (α, β, γ) for 56 days (uptake phase) followed by 112 days (depuration phase) of unfortified food. A fourth group of fish were exposed to unfortified food for the duration of the experiment. Fish (n=4) from all four aquaria were sacrificed on days 0, 7, 14, 56, 63, 70, 112 and 168 and muscle tissue was extracted and analyzed for diastereoisomer concentrations by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS). Bioaccumulation of the γ diastereoisomer was linear during the uptake phase while the α and β diastereoisomers were found to increase exponentially with respective doubling times of 14.1 and 20.5 days. Both the β and γ diastereoisomers followed first order depuration kinetics with calculated t1/2’s of 94 ± 25 and 84 ± 51 (± 1 × standard error) days, respectively. The BMF for the α diastereoisomer (BMF = 4.1) was one and a half times greater than the β-diastereoisomer (BMF = 2.6) and about one fifth larger than the γ-diastereoisomer (BMF = 3.6). The large BMF for the α diastereoisomer is consistent with this diastereoisomer dominating higher trophic level organisms in wildlife. Although the BMF of the β diastereoisomer suggests that it will biomagnify, because it is present in small quantities in commercial mixtures it is rarely detected in environmental samples. Results from these studies also provide evidence of bioisomerization of the β and γ diastereoisomers. Most importantly, the α diastereoisomer which was recalcitrant to bioisomerization by juvenile rainbow trout in this study and known to be the dominant diastereosiomer in fish, was bioformed from both the β and γ diastereoisomers. To our knowledge, this is the first report of bioisomerization of a halogenated organic pollutant in biota. / May 2006

In the poultry industry, further processed meat products have the highest share in the market, and because there is a growing demand of food products with enriched amounts of unsaturated fatty acids, the objectives of this research were to assess lipid oxidation development and quality characteristics of chicken meat as affected by dietary fat and vitamin E levels. Broilers were fed during six weeks with diets containing animal/vegetable, lard, palm kernel, soybean, conjugated linoleic acid, flaxseed, or menhaden oil. Each lipid diet was supplemented with either a control (33 or 42 mg/kg) or a supranutritional level (200-400 or 200 mg/kg) of vitamin E. Breast and thigh meat, or skin, were processed, packaged, and refrigerated as raw meat, cooked patties, or cooked sous vide meat. The results showed that the chicken meat fatty acid composition reflected those from the dietary fats. In the meat or skin there was a higher lipid oxidation susceptibility as the proportion of unsaturated fatty acids increased, shown as malonaldehyde values, particularly in the treatments with low supplemented level of vitamin E (P<0.05). The relative lipid oxidative stability of the meat decreased in consecutive order from raw, cooked sous vide, and cooked meat patties. Sous vide cooked meat developed lipid oxidation at a slow rate and showed not to be affected by nonheme iron values. Dietary fat and vitamin E level affected breast meat lightness (L* color space) values (P<0.05), but not muscle pH, Allo-Kramer shear force, or water holding capacity. In conclusion, the increment in the proportion of unsaturated fatty acids increases the susceptibility to lipid oxidation in the meat. Supranutritional supplementation levels of vitamin E are more effective at inhibiting the lipid oxidation development in chicken meat than some current levels used by the poultry industry. Neither dietary fat nor vitamin E level seems to affect the development of pale, soft, and exudative meat condition in chicken meat.

In recent years, dietary calcium intake among children and adolescents has fallen sharply. This trend is alarming because childhood and adolescence are the primary ages for building bone mass. Therefore, an interactive website, Clueless in the Mall (http://calcium.tamu.edu) was developed targeting youth to increase knowledge, improve attitudes, and equip them to incorporate calcium-rich foods into their diets. This website was created with the help of adolescents at every stage of development and has been pilot tested with adolescents at home and in school, showing improvements in knowledge and attitudes. However, the website has not been tested for effectiveness in changing behaviors, specifically for increasing calcium intake. The present study was conducted to measure the effectiveness of the website for changing knowledge, attitudes, and behaviors. The hypothesis of this investigation was that the website intervention would significantly improve attitudes and knowledge about calcium and increase dietary calcium intake among adolescents and pre-adolescents who took part in the study. After the group-administered Food Frequency Questionnaire (FFQ) was validated among a local church youth group, a total of 126 middle school and high school students were recruited from 12 local public school classes to participate. Each student took three questionnaires during class time to measure baseline knowledge, attitudes, and behaviors (including calcium intake using the FFQ). Then each student took one class period to view the calcium website. Four to six weeks later, the investigators returned to administer the same three tests to each student. Demographic information was collected, and data were analyzed using paired samples t-tests and analyses of variance (ANOVA). Results demonstrated that the website alone was sufficient to improve knowledge scores; however, it was not enough to change attitudes and behaviors significantly. In conclusion, the website should be used to promote and reinforce health behaviors, but should not be expected to stand alone as an intervention.

Studies in other species indicate high protein diets increase urinary calcium (Ca) excretion and may lead to negative calcium balance and reduced bone density. As overfeeding of protein is commonplace in the horse industry, this study was undertaken to determine the effects of excess dietary protein on growth, physiologic response, mineral balance, bone density, and bone geometry in immature horses. Sixteen 10-month-old American Quarter Horses were blocked by age and sex into two dietary treatments. The control diet was formulated to provide the NRC (1989) recommended concentration of crude protein, while the high protein diet provided 130% of NRC (1989) recommendations. All other nutrients were formulated at or slightly above NRC (1989) recommendations. Blood samples, feces, and urine were collected during the 116-day study to determine any diet effect on pH and mineral balance. Radiographs were made of the left third metacarpal (MCIII) to determine bone density via radiographic bone aluminum equivalence (RBAE), and bone geometry was determined metrically from the radiographs. Urine pH decreased over time (p < 0.001), but there were no diet effects on blood pH or urine pH. Conversely, when normalized to day 0 values, fecal pH was reduced by feeding the high protein treatment (p < 0.02). Density of dorsal and palmar cortices increased over time (p < 0.001), but no differences were observed between diets. But, normalized total medial-lateral (ML) width of the MCIII was higher in the control diet (p < 0.05). Fecal Ca loss was greater in horses fed the high protein diet (p < 0.005), while Ca absorption and retention were lower for horses on the high protein treatment (p < 0.02). Phosphorus (P) balance was not different between diets, although feeding the high protein diet resulted in higher P intake overall (p < 0.001). While excess dietary protein may decrease fecal pH, increase fecal Ca excretion, and decrease Ca absorption and retention, there was no consistent effect of the high protein diet on bone density over the course of this study. Further research is necessary to determine if feeding high-protein diets is detrimental to bone quality in the growing horse.

Thesis (B.G.S.)--Texas Tech University, 2000. / Includes bibliographical references (leaf 30).