Experiments were conducted to investigate the effect of reducing dietary anion-cation balance (AC-balance), defined as meq $ sp circ$(Sodium + Potassium)-(Chloride + Sulfur) S, on calcium (Ca) metabolism. Reducing the dietary AC-balance from +314 to $-22$ (meq kg$ sp{-1}$ dry matter (DM)) did not affect plasma Ca level but reduced Ca retention mainly due to a 10-fold increase in urinary Ca excretion with similar rate of apparent absorption. It also decreased urine pH and titratable acidity. The response to induced hypocalcemia created by the infusion of 4.6% EDTA solution revealed that reducing dietary AC-balance from +354 to +37 (meq kg$ sp{-1}$DM) did not affect the volume of the compartment, within which there was rapid equilibration of free Ca but tended to increase the rate of Ca mobilization from it during the infusion. The Ca kinetic study with a four-compartment model indicated that reducing dietary AC-balance from +338 to $-127$ (meq kg$ sp{-1}$DM) during the eucalcemic period and from +429 to $-147$ (meq kg$ sp{-1}$DM) during an EGTA-infusion period (simulated lactational Ca loss) caused hypercalciuria and increased ionized form of plasma Ca. Increased true intestinal Ca absorption and reduced bone accretion were observed in the lowest AC-balance diet only during the EGTA-infusion period. There were no differences in the size of total exchangeable Ca pool but the amount of Ca movement between them tended to increase in reduced AC-balance diets during both periods. Results indicated that feeding reduced AC-balanced diet may have a beneficial role in preventing parturient paresis (milk fever) by increasing Ca flux through the exchangeable Ca pool and Ca mobilization capability.

Four studies were conducted to investigate some factors affecting milk fatty acid composition of dairy ewes. The first study was performed to determine the influence of freezing temperatures and storage time on ovine milk composition and cheese making. The other three experiments were conducted to examine the effects of dietary added fats with different profiles of fatty acids from canola, sunflower and flaxseeds on animal performance, nutrient utilization, milk yield and cheese making. The main emphasis was on fatty acid composition, particularly CLA and Omega-3 fatty acids, in milk and cheese. Results showed that: (1) feeding up to 8% of canola, sunflower and flaxseed had no adverse effects on dry matter intake and total tract digestibilities of dry matter, neutral detergent fiber, acid detergent fiber and crude protein, while the digestibilities of fatty acids and gross energy were increased with oilseed supplementation; (2) feeding flaxseed to lactating ewes up to 260g/ewe/d increased milk yield by up to 8.4%, and fat content by up to 14.3% without adversely affecting other milk components or cheese yield and composition; (3) Oilseed supplementation increased milk concentrations of long-chain and unsaturated fatty acids in the expenses of short-chain, medium-chain and saturated fatty acids. The concentrations of CLA and Omega-3 fatty acids were also increased by oilseed supplementation; (4) the manipulated fatty acids profiles can be reflected in cheese; (5) good quality cheese can be produced from ovine milk frozen at -15°C and -25°C for up to 6 months without influencing cheese content of fat and protein and fatty acid composition. / In conclusion, ovine milk with nutritionally healthy characteristics can be produced by feeding ewes diets with oilseeds, and freezing storage of milk for up to 6 months at -15°C or -25°C does not significantly affects milk composition including fatty acid composition. The characteristics of milk can be reflected in cheese.

Taste is detected by cells of taste buds in the oral cavity. Mammalian taste buds contain three types of cells: receptor, presynaptic, and glial-like. Of these three, glial-like cells are the least studied. Their only known function is that they clear neurotransmitters from the extracellular space. The present work describes two previously undocumented properties of glial-like cells. First, Oxytocin receptor (OXTR) mRNA was detected by RT-PCR in taste tissue of mice. In the taste buds of Oxtr-YFP knockin mice, YFP was seen in glial-like taste cells and other cells immediately outside the taste bud, but no other cells in oral epithelium. Oxytocin (OXT) elicited Ca2+ responses from cells that resemble glial-like taste cells (by criteria including gene expression and lack of excitability). The EC50 for OXT in these cells was 33 nM, and responses saturated at 1 µM. 500 nM L-371,257 (an OXTR antagonist) significantly inhihited the responses to OXT. In a semi-intact preparation of lingual slices, OXT did not alter bitter tastant-evoked Ca2+ responses. Further, in behavioral studies, OXT (10 mg/kg i.p.) did not alter the responses of mice to aversive salty (NaCl), bitter (quinine), or sour (citric acid) solutions. In contrast, OXT (0.1 mg/kg i.p.) significantly decreased taste behavioral responses to low-to-intermediate concentrations of sucrose. My data suggest that OXT may modulate sweet taste sensitivity in vivo by acting on glial-like cells in taste buds. Second, Renal Outer Medullary K channel (ROMK) mRNA was also detected by RT-PCR in taste buds . Immunostaining revealed that ROMK is localized to the apical tips of glial-like taste cells. In the kidney, ROMK, apically localized in nephron epithelium facilitates a unidirectional flow (i.e. excretion) of K+. I suggest that, analogous to glia in the central nervous system, glial-like taste cells homeostatically redistribute extracellular [K+ ] within taste buds to maintain their sensitivity. The results of this study reveal that glial-like taste cells resemble nervous system glia in more ways than simply clearing neurotransmitters. They may also modulate the sensory output of the taste bud and buffer the extracellular [K+]. A more active role for glial-like cells in the functioning of the taste bud should be investigated.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 102-123). / Microfiche. / xiii, 123 leaves, bound ill. (some col.) 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 127-136). / x, 136 leaves, bound ill. 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 70-81). / vii, 86 leaves, bound ill. (some col.) 29 cm

ABSTRACT The Southern Rocklobster, Jasus edwardsii, supports a commercial fishing industry worth $180 million AUD per annum, the majority of which is exported live to Asia. The current market demands for smaller rocklobsters can sometimes result in discounting of the larger individuals, a significant financial loss for the industry. Value adding of large rocklobster into processed product may help combat this loss; however, there is financial risk associated with the development of new products for new markets without first understanding the product variability. The aims of this thesis were to quantify raw product flesh characteristics using physical, biochemical and sensory approaches, determining the extent of variation in those characteristics, and finally to investigate the potential biological and post-harvest sources of that variation. One of the initial requirements was the establishment of previously undefined key descriptors of sensory properties for raw rocklobster flesh, which were texture (chewiness and crunch), flavour (metallic, lobster and sweetness) and appearance (pinkness and translucency) (Chapter 2). These were tested using a combination of triangle tests and a hybrid descriptive test using a trained sensory panel. The trained panel found no significant difference in the texture, flavour or appearance of raw flesh between large and small rocklobster (Chapter 4). However, differences in the sensory descriptors of flesh translucency, pinkness and lobster flavour were significantly influenced by frozen storage of the product and the section of tail from which a sample was sourced (Chapter 4). Biochemically, these differences were largely associated with variation in flesh adenylates, with AEC, IMP load, total adenylate pool and K value being identified as the key contributors. Of all the potential sources contributing to variation in flesh biochemical properties, post-harvest factors such as �batch� (i.e. rocklobsters processed on a single day) had a dominant influence (Chapter 3). The difference detected in flesh characteristics between batches was greater than any seasonal pattern such as moult stage. Biological variables such as rocklobster condition and shell colour had no significant influence on flesh properties (Chapters 3 & 4). White rocklobsters are currently discounted in the live export trade; however this does not appear to be necessary for value added product owing to the lack of significant differences to red rocklobsters across a range of biochemical parameters (Chapter 3). Rocklobster physical condition (which has previously been associated with prior stress) was not shown to affect flesh biochemistry or sensory properties (Chapter 4). This result was not expected and may reflect the potential recovery of rocklobsters sampled in this study prior to processing. These findings suggest that commercial rocklobsters, which have had similar recovery, are unlikely to show reduced sensory properties. Recent commercial interest has focussed on holding rocklobster in tanks to provide year-round supply. As a result, the impacts of tank-holding and feeding on rocklobster flesh sensory properties were investigated (Chapter 5). Rocklobsters that were tank-held and fed for up to four months produced flesh with similar physical, biochemical and sensory properties to freshly caught rocklobster. Tank-holding therefore offers a viable solution to operators wanting a year-round supply of fresh product from a resource which is subjected to a restricted fishing season. A Japanese consumer panel was established to assess the greatest differences in flesh properties as detected by the trained sensory panel. The Japanese consumer panel assessed raw flesh from fresh, short and long-term frozen storage treatments (Chapter 4). This consumer panel detected similar differences in taste, texture and flavour as the trained panel, and whilst no significant overall preference was detected, half of the panellists showed a preference for rocklobster product that had been stored frozen for 18 months. The findings from this research are useful for the commercial industry as they indicate that raw rocklobster flesh has little variation associated with discounting factors such as size and shell colour. Although the greatest variation in flesh biochemistry was seen with frozen storage, even long term storage produced rocklobster flesh properties which were favourable for some panellists. The commercially caught Southern Rocklobster appears to have raw flesh properties well suited for a value added product.

Includes bibliographical references (leaves 290-309) / 310 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates aspects of the intake and utilization of barley grain and grain legume supplements by sheep fed low quality pasture hay and when grazing mature summer pastures. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1987

152 leaves : ill., photos., tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1979

ix, 131 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1974)--University of Adelaide, Dept. of Zoology, 1974