Antibiotics are added to animal feeds as prophylactic agents and to encourage weight gain in livestock. However, there is concern that the widespread use of antibiotics in animal agriculture encourages for the selection of resistance genes and has contributed to the rise of multiply antibiotic resistant strains of pathogenic bacteria. For this reason, there is interest in quantifying antibiotics in environmental samples. The determination of three antibiotics in swine waste, namely chlortetracycline, tetracycline and oxytetracycline, using LC-MS with electrospray ionization is presented here in. Antibiotics from swine waste were quantified across the lifespan of the swine. Trends were present in each of the four life stages (gestation, farrowing, nursery, and finishing). The nursery stage of life presented the most dominate concentrations and the most consistent trend in antibiotic concentrations.

No description available.

Bibliography: leaves 151-166. / xi, 166 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the development of two novel and complementary analytical approaches for assaying cyanoalanine non-protein amino acids. These assays are used to determine the distribution of these compounds both within and between plants and to identify accessions of common vetch which contain low levels of the cyanoalanine non-protein amino acids in germplasm collections. These analytical tools are used to correlate toxicity observed in animal feeding experiments with the cyanoalanine content. This thesis covers also the first report of the use of diffuse reflectance using dispersive infrared spectrometry for the "in situ" quantification of specific organic components from plant tissue as well as the first use of micellar electrokinetic chromatography for the quantitative analysis of 9-fluorenylmethyl chloroformate (FMOC) derivatised and non-derivatised components of extracts from plant material. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1997

Addendum pasted onto front end-paper. / Bibliography: leaves 176-216. / x, 216 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this project is to determine why LR3IGF-1 has such divergent effects in two different species. The study investigates the endocrine regulation of IGF-I and IGF binding protein-3 (IGFBP-3) in the pig and determines the effects of IGF-I and LR3IGF-I treatment on porcine IGF-I and IGFBP-3 expression at the gene and protein level. / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1997

Typescript / 420 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.)--University of Adelaide, Dept. of Agronomy, 1965

The first three experiments of this thesis examined the effects of particle size reduction of grains in relation to feed form (mash vs. pellet), grain type (wheat vs. maize) and xylanase supplementation on broiler performance, energy utilisation, digestive tract development and digesta parameters. The fourth experiment examined the interaction between wheat hardness and xylanase supplementation. The effects of insoluble fibre source and whole wheat inclusion were studied in the fifth experiment. In the first experiment (Chapter 4), pelleting reduced nitrogen-corrected apparent metabolisable energy (AMEn), but broiler performance was superior in birds fed pelleted wheat-based diets compared to those fed mash diets. Feed form had a greater effect on various measured parameters than did particle size. Pelleting evened out differences in particle size distribution between treatments and, as a result, wheat particle size had no effect on the performance of broilers fed pelleted diets. In contrast, the second experiment (Chapter 5) showed that differences in particle size distribution persisted between diets after pelleting and, as a result, coarse grinding of wheat or maize improved broiler performance compared to those fed diets based on fine particles. These results may be related, in part, to changes in size distribution following pelleting. In mash diets, inconsistency in performance reponses were found. In the first experiment (Chapter 4), coarse grinding of wheat improved weight gain and feed per gain compared to medium grinding. In the third experiment (Chapter 6), however, grinding particle size had no influence on broiler performance. The observed discrepancy suggests involvement of other factors such as wheat cultivar and grain hardness. Data reported in Chapter 6 showed that xylanase supplementation improved feed per gain of birds fed the coarse particle size diet, but had no effect on those fed the medium particle size diet. In Chapter 7, there was a significant interaction between wheat hardness and xylanase supplementation due to the improved feed per gain and AMEn of birds maintained on hard wheat-based diet, while there was no effect of xylanase on sort wheat-based diet. These findings suggest that the efficiency of exogenous enzymes is influenced by both particle size and wheat hardness. Data reported in Chapter 7 showed that inclusion of soft or hard whole wheat pre-pelleting produced different particle size distributions in the pelleted diets. This suggested that hardness of the grain must be considered when choosing whole wheat for inclusion in broiler diets. Data on the effect of feed particle size on its subsequent distribution in poultry digesta are scanty. Results reported in Chapters 4 and 5 showed that there was no effect of feed particle size within feed form on duodenal digesta particle size. On the other hand, particle size of duodenal digesta was influenced by feed form (mash vs. pellet). Wheat hardness was also found to influence the particle size of proximal (duodenum and jejunum) intestinal digesta (Chapter 7). These results indicated that the gizzard does not uniformly reduce the size of all particles. However, the gizzard appears highly efficient in grinding large particles, although some large particles escape the grinding. The final experiment demonstrated that the effects of insoluble fibre on digestive tract development and broiler performance differed depending on the fibre source. Wood shavings, a source of coarse insoluble fibre, increased relative gizzard size and improved corrected feed per gain and ileal starch digestibility. In contrast, cellulose, a source of fine insoluble fibre, had no influence on these parameters. In conclusion, dietary manipulations, which stimulated gizzard development, positively influenced broiler performance and starch digestibility. The findings of this thesis suggest that energy savings during feed processing could be achieved by coarse grinding of grains with no adverse effect on broiler performance and that cereals used in broiler diets can be ground more coarsely than the current practice. Wheat hardness appears to be an important criterion to consider when choosing a cultivar for whole wheat inclusion in broiler diets. Another major finding was that the effectiveness of exogenous xylanase in wheat-based diets could be improved by considering factors such as particle size and wheat hardness.

Elk (Cervus elaphus spp) are widely used as a terminal sire in the New Zealand deer industry because elk red deer crosses are heavier at 12 months of age than pure-bred red deer (Cervus elaphus) and therefore better fit market demands. However, it is unclear whether nutritional requirements differ between genotypes. A series of experiments compared young (4 - 12 months) red deer and red deer-elk cross (hybrids) in various aspects of their nutrition. Single genotype groups (10-15) of red deer and hybrid weaner stags were offered one of four pasture allowances (2 to 12 kg DM/head/day) on a rotationally grazed mixed ryegrass - white clover pasture system for 9 weeks in winter (June-July), spring (October-December) and summer (February - March). Stags were weighed and given a new allocation of pasture weekly. Pre-grazing pasture mass ranged from 800 kg DM/ha for low pasture allowances to 4500kg DM/ha for higher allowances. Winter live-weight gain was low (40-80 g/day), relatively unaffected by pasture allowance and similar for both genotypes. In spring however, hybrids gained live-weight on average 100 g/day more than red deer across all pasture allowances and the response to additional pasture allowance was large (110 g/day at 2kg DM/head/day to 300 g/day at 9.5 kg DM/head/day). At the highest pasture allowance, hybrids grew faster (350 g/day) than red deer (250 g/day), although red deer were able to achieve this live-weight gain when offered less pasture (4 vs 12 kg DM/head/day, respectively). Summer live-weight gain was lower for both genotypes and responded less to increases in pasture allowance than during spring. A second experiment compared the live-weight gain of both genotypes at ad lib feeding in an indoor environment where intake could be accurately measured. A group of red deer (n =15) and a group of hybrid (n =15) weaner stags were housed indoors during winter (3 June - 27 August) and spring (16 October - 16 December) and fed a pelleted grain based ration ad lib. Mean daily intake for each group (kg DM/head/day) was calculated as the difference between feed offered and feed refused. Hybrids had a significantly higher (P< 0.05) absolute DM intake compared with red deer in both seasons, although when expressed on a metabolic body weight basis, there was no difference between genotypes irrespective of season. Live-weight gain during winter did not differ significantly between genotypes regardless of whether it was expressed on an absolute or metabolic weight basis. Spring live-weight gain, expressed both on an absolute and metabolic live-weight basis, was significantly higher for hybrids compared with red deer (P<0.05). Red deer and hybrids increased their feed intake from winter to spring by 20% and 24% respectively on a metabolic body weight basis. Although the difference between genotypes in their seasonal increase in intake was relatively small there was a large difference in their pattern of live-weight gain. Red deer exhibited a 34% and hybrids a 76% seasonal increase in live-weight gain expressed on a metabolic live-weight basis from winter to spring. These results indicate the greater rate of live-weight gain displayed by hybrids compared with red deer was not associated with a greater ad lib intake (expressed on a metabolic body weight basis) and the seasonal increase in live-weight gain is greater for hybrids than for red deer. A further experiment estimated the energy requirement for maintenance of both genotypes. Five deer of each genotype were housed in separate pens (3.5m²) during winter (3 June - 27 August) and spring (16 October - 16 December) and randomly assigned to one of 5 feeding levels (0.5, 0.6, 0.7, 0.8, or 0.9 times estimated ad lib intake of l.5 and l.7 kg DM/head/day during the winter and 3.0 and 3.3 kg DM/head/day during the spring for red deer and hybrids, respectively. Maintenance requirement was determined by regression analysis of live-weight gain on ME intake. Although there was no seasonal effect on the live weight gain response to intake there was a significant genotype effect. To maintain live weight during either season, hybrids required a higher ME intake (0.52 MJ ME/W0.75/day compared with red deer 0.41 MJ ME/W0.75/day). The rate of increase in live weight gain to increasing intake declined as intake increased and more so for red deer than hybrids. The final experiment in the series involved individually housed deer and aimed to more precisely determine differences in maintenance requirement and examine the difference in composition of gain between genotypes. In addition, in vivo apparent DM digestibility was measured in both genotypes. Red deer (n=7) and hybrid weaner stags (n=7) were housed in individual pens for a period of 8 weeks in both winter (July - August) and spring (November - December) and offered one of 7 feeding levels which ranged from maintenance to ad lib. During each 8 week experimental period, live weight gain, apparent digestibility and feed intake were measured. Immediately prior to, and at the conclusion of each 8 week period body composition was estimated using computer-assisted topography (CT scan). In winter, there was no significant difference in the live weight gain response to intake although red deer tended to have a higher (44 vs 55 MJ/kg) requirement for gain than hybrids. In spring, red deer had a lower requirement for maintenance (0.35 vs 0.47 MJ ME/W0.75/day) but a greater requirement for live weight gain (64 vs 35 MJ/kg) than hybrids. In spring, mean ad lib intake was about 30% higher than in winter and was greater for hybrids than for red deer. Energy retention in whole body (kJ/W0.75/day) did not differ between genotypes in either winter or spring but both the energy requirement for zero energy balance (0.59 vs 0.48 MJ ME/W0.75/day) and the efficiency of utilisation (0.37 vs 0.24) was greater in spring than in winter. The disparity between live weight gain and whole body weight gain may have been due to differences in gut fill. There was no significant difference between genotypes in relative growth coefficients for lean, bone or adipose tissue in whole body. However hybrids tended to have a higher winter and lower spring growth coefficient for fat compared with red deer. Growth coefficients for adipose, lean and bone, respectively were 0.983, 1.063 and 1.026 for winter and 1.02, 0.708 and 1.727 for spring. At the same whole body weight, deer in October had less adipose tissue than in August. It is unclear whether this represents a strategy for rapid spring growth or is an artefact of experimental protocol. Apparent dry matter digestibility (DMD) did not differ between genotypes but was higher by between 7 and 15 percentage units in winter compared with spring. Unexpectedly, digestibility was positively correlated with intake. Digestibility increased by 2.6 percentage units for every 10g DM/W0.75/day increase in either season in one group and 4.1 and 2.1 percentage units for deer in winter and spring respectively in another group. Errors in faecal collection were discounted as causes of the unexpected result.

Two experiments were conducted to examine the interrelationships between body composition at parturition, herbage allowance during lactation and milk production. Detailed measurements of feed intake and changes in body composition allowed estimates of maintenance energy requirement and efficiency of use of energy for milk production. Dorset ewes were offered low (L-) or high (H-) herbage allowances during pregnancy to achieve post-partum body weights, respectively, of about 50 and 60-65 kg. During the first 6 weeks of lactation herbage allowances were approximately 2 (-L), 5 (-M and -Mm) and 8 (-H) kg DM/ewe/d and feed intake was determined using chromic oxide dilution. In the first experiment (Expt.A) ewes were machine-milked and in the second (Expt.B) they were suckled by twin lambs with a further group (-Mm) machine-milked. Samples of ewes were slaughtered during early pregnancy, post-partum, and after 6 weeks of lactation. Body weight differences post-partum between L- and H- groups were 10 and 15 kg in Expts.A and B respectively. During lactation body weight changes appeared erratic, particularly in Expt.B, owing to the effects of variation in gut fill. Daily feed intake of machine-milked ewes on -M and -H allowances reached a maximum (1.9-2.2 kg OM/ewe/d) 2-3 weeks after parturition but ewes rearing lambs on similar allowances showed maximum intake (2.5-2.8 kg OM/ewe/d) during the first week. Mean intakes during lactation were 58, 69 and 73 g DOM/kg W•⁷⁵/d respectively for -L, -M and -H groups machine-milked and 51, 75 and 83 g DOM/kg W•⁷⁵/d respectively for -L, -M and -H groups rearing twin lambs. In both experiments ewes in L- groups had approximately 14% greater mean intake (g DOM/kg W•⁷⁵/d) during lactation compared with those in H- groups. Mean daily milk production of ewes rearing lambs was 2.0, 2.5 and 2.7 kg/d respectively in -L, -M and -H groups and was 33-52% greater than that for machine-milked ewes offered similar herbage allowances. In both experiments L- ewes had 14% greater milk yield (g/kg W•⁷⁵/d) compared with H- ewes. Mean lamb growth rates in Expt.B averaged 209, 254 and 268 g/lamb/d in -L, -M and -H groups, respectively. Lambs in the H- group were approximately 11% heavier at birth than those in the L- group and their mean growth rate was 20 g/d greater. Body fat and energy content of live ewes at the start of lactation was predicted using regression relationships from ewes slaughtered post-partum. There was large variation in the energy content of body weight loss during lactation (-37 to +140 MJ/kg) owing to variation in weight of gut fill and changes in chemical composition of the empty body. In Expt.A the body fat content of ewes during early pregnancy was 16.9 kg. Predicted values post-partum were 10.0 and 15.7 kg in L- and H- groups, respectively. During lactation all groups showed body fat losses which ranged from 53 (LH) to 120 g/d (HL). Body fat content during early pregnancy in Expt.B was slightly greater (19.0 kg) than in Expt.A and predicted values post-partum were 11.5 (L-) and 19.7 kg (H-). Fat mobilization during lactation was greater than in Expt.A, and ranged from 157 (LH) to 287 g/d (HL). In both experiments there were losses in body protein during pregnancy in L- ewes (5 and 15 g/d in Expts.A and B respectively). During lactation, protein losses were most evident in H- ewes, being greatest in HL groups (26 and 43 g/d in Expts.A and B respectively). Water: protein ratio in the empty body showed a progressive increase during pregnancy and lactation in both experiments. Estimated maintenance energy requirement for machine-milked ewes tended to be greater for H- (.236 MJ ME/kg W/d) compared with L- ewes (.205 MJ ME/kg W/d) but was similar for both groups of ewe rearing lambs (average of.238 MJ ME/kg W/d). Efficiency of use of ME above maintenance for milk production (K₁) in L- and H- groups was, respectively, .69 and .95 in machine-milked, and .69 and .64 in suckled ewes. Energy from mobilized body tissues was utilized for milk production with respective efficiencies in L- and H- ewes of .23 and .35 in machine-milked, and .40 and .50 in suckled ewes. Efficiency of conversion of total energy available (i.e. ME above maintenance and mobilized tissue energy) to milk energy (K₁(t)) when compared among all groups in both experiments, tended to decrease (from .84 to .51) with increasing body energy mobilization. There was a positive relationship, however, between K₁(t) and the proportion of mobilized energy derived from body protein. Metabolizable energy intakes in the present experiments appeared to be 10-15% greater than calculated requirements from ARC (1980). Estimates of ME requirements for lactating ewes at pasture, in relation to body weight, level of milk production and body energy change, have been calculated based on the present data.

Leucaena leucocephala and Sesbania sesban in dry form were fed as supplements to goats feeding on a low quality basal diet of barley straw. Each browse supplement was fed at four levels: 0 %, 0.83 % liveweight (LW), 1.66 % LW and at ad libitum. The intakes of dry matter (DM) and organic matter (OM), DM and OM digestibility, nitrogen (N) digestibility and balance, and liveweight gain were evaluated during a 5 week trial. For goats offered both leucaena and sesbania there was no significant (p<0.05) difference in DM or OM intakes between 0.83 % LW and 1.66 % LW levels of browse supplementation. When both lecaena and sesbania were offered ad libitum the DM and OM intakes were significantly (p<0.05) lower than for either 0.83 % LW or 1.66 % LW level of supplementation. Feeding both leucaena and sesbania increased the DM and OM digestibility coefficients significantly over thos of the controls. The growth rates for goats supplemented with leucaena at various levels were not significantly different from each other. For the goats offered sesbania at ad libitum, their growth rates were significantly lower than for those fed sesbania at either 0.83 % LW or 1.66 % LW. The apparent digestibility of nitrogen (ADN) was not significantly different among leucaena supplemented treatments. For goats offered sesbania, the ADN was significantly higher than for the controls. The ability of browse supplements to increase intakes and digestibility of both dry matter and organic matter is discussed.

[Truncated abstract] Current understanding of atherosclerosis suggests that it is a chronic inflammatory disease, and that increased oxidative stress may be an important pathological event contributing to the disease process. There has been interest in the ability of dietary derived nutrients such as vitamin E, to act as antioxidants and protect against atherosclerosis. Despite promising epidemiological data which suggested benefits from a higher intake of &alpha-tocopherol (&alphaT), one of the major forms of dietary vitamin E, for protection against atherosclerosis, large scale, randomised controlled trials have generally shown no protective effect of high dose &alphaT supplementation. Recent studies suggest that the other major dietary tocopherol isomer, &gamma-tocopherol (&gammaT), may possess biological activities not shared by &alphaT. Supplementation with &gammaT, or mixtures of tocopherols rich in &gammaT, have shown biological activities that may help protect against atherosclerosis. The aim of this PhD project is to further characterise the biological relevance of ?T for protection against CVD... Both ?- and mixed tocopherol supplementation resulted in reduced plasma F2-isoprostanes (P < 0.001 and P = 0.001, respectively) but did not affect 24 hour urinary F2-isoprostanes and erythrocyte antioxidant enzyme activities. Neither &alphaT nor mixed tocopherol supplementation affected any measured plasma markers of inflammation. The tocopherol supplementation also did not affect COX-2 activity as assessed by 14 stimulated whole blood prostaglandin E2 synthesis, and urinary prostacyclin metabolite output. Compared to the placebo group, stimulated neutrophil leukotriene B4 (LTB4) production decreased significantly in the mixed tocopherol group (P=0.02) but not in the &alphaT group (P=0.15). The ability of both pure &alphaT and mixed tocopherol supplementation to reduce systemic lipid peroxidation in patients with type 2 diabetes, suggests potential benefits of vitamin E supplementation in this population. However, despite decreasing oxidative stress, our results also suggests that in populations with well controlled type 2 diabetes, supplementation with either &alphaT, or mixed tocopherol rich in &gammaT, is unlikely to confer further benefits in reducing systemic inflammation. Future research into the possible unique biological activity of different tocopherol isomers other than &alphaT, for example, their ability to affect the 5-LO pathway and production of inflammatory mediators such as LTB4, is warranted.