A dor encontra-se inerente aos procedimentos de tratamento intensivo dos recém-nascidos pré-termo em Unidade de Terapia Intensiva Neonatal. As experiências precoces e repetidas de dor podem ter efeitos a longo prazo para os recém-nascidos vulneráveis. A Academia Americana de Pediatria e a Sociedade Pediátrica Canadense recomendam o uso da solução de sacarose como rotina para alívio da dor em Unidade de Terapia Intensiva Neonatal, durante os procedimentos invasivos e dolorosos. O presente estudo teve por objetivo avaliar as reações de dor de neonatos pré-termo durante procedimento de coleta de sangue, analisando o momento da punção, assim como os efeitos do manuseio dos neonatos para a anti-sepsia e o curativo e avaliar a eficácia da intervenção com solução de sacarose a 25% no alívio da dor administrando-a em dose única de 0,5ml/Kg. Trinta e três neonatos foram distribuídos randomicamente em dois grupos: Grupo Sacarose (n=17) e Grupo Água (n=16). Os neonatos foram avaliados durante dois dias consecutivos. Na primeira avaliação, os neonatos de ambos os grupos não receberam nenhuma substância antes do procedimento doloroso. Na segunda avaliação, o Grupo Sacarose recebeu sacarose oral e o Grupo Água recebeu água estéril, dois minutos antes do procedimento invasivo e doloroso de punção para coleta de sangue. Cada avaliação foi dividida em cinco fases: Linha de Base, Preparação para Punção (anti-sepsia), Punção, Recuperação com Manuseio (curativo) e Recuperação sem Manuseio. O indicador de dor foi avaliado pela atividade facial, que foi mensurada pelo Neonatal Facial Coding System. O nível de ativação dos neonatos foi medido pelo estado de vigília e sono e pela freqüência cardíaca. A análise entre grupos e intra-grupo dos dados revelou que no primeiro dia de avaliação os neonatos anteciparam a reação ao estímulo doloroso de punção, apresentando elevação significativa dos indicadores atividade facial, estado de vigília e sono e freqüência cardíaca avaliados na Preparação para Punção. Ambos os grupos mostraram alta reatividade comportamental e fisiológica na fase de Punção, em comparação à Linha de Base. Durante a recuperação, o indicador fisiológico de freqüência cardíaca continuou elevado. No segundo dia de avaliação os neonatos que receberam 0,5ml/Kg de solução de sacarose a 25% apresentaram menores escores de atividade facial, indicativo de menos dor, em comparação aos neonatos que receberam água estéril, antes, durante e após o procedimento de punção para coleta de sangue. Entretanto, o indicador fisiológico de freqüência cardíaca não apresentou diferença significativa entre os grupos. Conclui-se que a dose de 0,5ml/Kg de solução de sacarose a 25%, recomendada para a administração da substância em doses repetidas, foi eficaz no alívio de dor, avaliada por meio da redução de indicadores comportamentais. Entretanto, o indicador fisiológico continuou elevado, sugerindo a necessidade de outras medidas de conforto associadas à sacarose, com a finalidade de atenuação do estado de ativação e irritabilidade do sistema nervoso central. / Pain is inherent to the intensive treatment procedures offered to preterm neonates in Neonatal Intensive Care Units. The early and repeated experiences of pain may have a long-term effects for the vulnerable neonates. The American Academy of Pediatrics and the Canadian Pediatric Society recommend using a sucrose solution for pain relief in NICU during invasive and painful procedures. The present study had the purpose to assess the pain reactions of preterm neonates during a procedure for blood collection, evaluating the moment of puncture as well as the effects of handling the neonates for antisepsis and for bandages, and evaluating the efficacy of the intervention with the sucrose solution at 25% for pain relief by administering a single dose of 0.5 ml/Kg. Thirty-three neonates were randomly assigned to two groups: Sucrose Group (n=17) and Water Group (n=16). The neonates were evaluated during two consecutive days. In the first assessment, the neonates from both groups did not receive the solution before the painful procedure. In the second assessment, the Sucrose Group received oral sucrose and the Water Group received sterile water, two minutes before the invasive painful procedure of puncture for blood collection. Each evaluation was divided into five phases: Baseline, Preparation for Puncture (antisepsis), Puncture, Recovery with Handling (bandage), and Recovery without Handling. The indicators of pain were evaluated by the facial activity, measured by the Neonatal Facial Coding System. The level of activation of the neonates was measured by their sleep-awake state and heart rate. The between and within-group data analysis revealed that, on the first day of evaluation, the neonates anticipated their reaction to the painful puncture stimulus, and showed a significant increase in the behavioral indicators of facial activity, sleep-awake state, and heart rate evaluated at the Preparation for Puncture. Both groups showed a high behavioral and physiological reactivity in the Puncture phase, in comparison to the Baseline. During recovery, the physiological indicator of heart rate continued high. In the second day of evaluation, the neonates who received 0.5 ml/Kg of the sucrose solution at 25% showed lower scores of facial activity, which indicates they experienced less pain in comparison to the neonates who received sterile water before, during, and after the procedure of puncture for blood collection. However, there were no significant differences in terms of the physiological indicator of heart rate. It is concluded that the dose of 0.5 ml/kg of sucrose solution at 25%, recommended for the administration in repeated doses, was efficient for pain relief, evaluated by means of the reduction of behavioral indicators. However, the physiological indicator remained high, which suggests there is a need for other comfort manegement associated to sucrose, with the aim to diminish the state of activation and irritability of the central nervous system.

A trajetória de desenvolvimento do neonato pré-termo se inicia no contexto da Unidade de Terapia Intensiva Neonatal, permeado pela presença contínua de diversos estímulos dolorosos. As experiências iniciais e repetidas de dor podem ter efeito em longo prazo para os neonatos vulneráveis. A Academia Americana de Pediatria e a Sociedade Pediátrica Canadense recomendam o uso da solução de sacarose como intervenção não-farmacológica para alívio de dor em neonatos, entretanto, a eficácia e segurança do uso continuado da sacarose necessitam de investigação. O presente estudo randomizado controlado duplo-cego teve por objetivos avaliar a eficácia da administração via oral da solução de sacarose a 25%, em esquema de doses repetidas no alívio da dor em neonatos pré-termo e avaliar os possíveis efeitos colaterais advindos do uso continuado da sacarose para os neonatos. Trinta e três neonatos pré-termo com muito baixo peso ao nascer foram distribuídos em dois grupos: Grupo Sacarose (n = 17) e Grupo Água (n = 16). Os neonatos foram avaliados durante quatro dias consecutivos, durante procedimento de punção para coleta de sangue. Cada avaliação foi dividida em cinco fases: Linha de Base, Preparação para Punção (antissepsia), Punção, Recuperação com Manuseio (curativo) e Recuperação sem Manuseio. O indicador de dor foi avaliado pela atividade facial, mensurada pelo Neonatal Facial Coding System (NFCS). O nível de ativação dos neonatos foi mensurado pelo estado de vigília e sono e pela frequência cardíaca. Na primeira avaliação, os neonatos de ambos os grupos não receberam nenhuma substância antes do procedimento doloroso. Nos três dias seguintes, o Grupo Sacarose recebeu 0,5ml/kg de sacarose oral e o Grupo Água recebeu água estéril, dois minutos antes de cada procedimento doloroso. Foram obtidos dados de evolução clínica dos neonatos nos prontuários médicos. Os resultados encontrados revelaram que no primeiro dia de avaliação os neonatos de ambos os grupos anteciparam a reação ao estímulo doloroso de punção, apresentando elevação significativa do escore do NFCS, do estado de vigília e sono e da frequência cardíaca, já na antissepsia, sendo que durante a recuperação a frequência cardíaca continuou elevada em comparação à fase de Linha de Base. A partir do segundo dia de avaliação, o Grupo Sacarose apresentou menores escores do NFCS e do estado de vigília e sono, durante o procedimento, em comparação ao Grupo Água. O indicador fisiológico de frequência cardíaca não apresentou diferença significativa entre os grupos, entretanto, a sacarose reduziu o tempo necessário para o neonato se recuperar e atingir a estabilidade fisiológica após passar pelo procedimento doloroso de punção. Não houve diferença significativa na evolução clinica dos neonatos de ambos os grupos, o que demonstra que a sacarose não causou efeitos colaterais em curto prazo aos neonatos. Conclui-se que a dose de 0,5ml/kg de solução de sacarose a 25% administrada em esquema de doses repetidas foi eficaz para o alívio da dor em neonatos pré-termo e não trouxe efeitos colaterais imediatos para o estado de saúde dos neonatos. / The development pathway of the preterm neonate begins in the context of the Neonatal Intensive Care Unit, permeated by the presence of several painful stimuli. Initial and repetitive pain may have long-term effect for vulnerable newborns. The American Academy of Pediatrics and Canadian Pediatric Society recommends the use of sucrose solution as non-pharmacological intervention for pain relief in neonates, however, the efficacy and safety of continued use of sucrose needs investigation. The present randomized controlled double-blind study aimed to assess the efficacy of oral administration of sucrose solution to 25% in repeated doses to relief pain in preterm neonates and to assess the possible side effects arising from the continued use of sucrose to newborns. Thirty-three preterm neonates with very low birth weight were divided into two groups: Sucrose Group (n = 17) and Water Group (n = 16). The newborns were assessed during four consecutive days during puncture procedure for blood collection. Each assessment was divided into five phases: Baseline, Antisepsis, Puncture, Dressing, and Recovery. The indicator of pain was assessed by facial activity, measured by the Neonatal Facial Coding System (NFCS). The level of activation of the neonates was measured by the sleep-wake states and heart rate. In the first assessment, the newborns of both groups did not receive any substance before the painful procedure. During the next three days, Sucrose Group received 0.5ml/kg of oral sucrose and Water Group received sterile water two minutes before each painful procedure. Clinical outcomes data of newborns were obtained in the medical records. The results showed that on the first day of assessment newborns of both groups have anticipated the reactivity to painful stimuli, with significant increase of NFCS score, sleep-wake states and heart rate as early as antisepsis, and during recovery heart rate remained increased in comparison to the Baseline phase. From the second day of assessment, the Sucrose Group had lower NFCS scores and sleep-wake states during the procedure, compared to the Water Group. The physiological indicator of heart rate showed no significant difference between groups, however, sucrose has reduced the time required for the infant to recover and achieve physiological stability after passing through the painful procedure of puncture. There was no significant difference in clinical outcome of newborn in both groups, demonstrating that sucrose did not cause short term side effects in neonates. The finding was that the dose of 0.5 ml/kg of sucrose solution to 25% administered in repeated doses was effective for pain relief in preterm and did not caused short term side effects to the health of newborns.

Foi conduzida uma série de experimentos onde se buscou definir: 1) o limite de tolerância do espermatozóide caprino a soluções hiperosmóticas de sacarose; 2) um diluente para criopreservação de sêmen que minimizasse as flutuações de volume celular. O limite de tolerância da membrana, avaliado pelo corante eosina-nigrosina, foi de 930 mOsm em soluções de sacarose em Ringer-lactato a 38oC. Os danos à integridade de membrana (IM), em osmolalidades acima deste valor, se estabeleceram no primeiro minuto de exposição e não se agravaram até 10 minutos depois. A motilidade (MOT) foi mais afetada que a IM. A rediluição abrupta em meio isosmótico causou dano extenso e proporcional ao grau de desidratação prévia. Nos experimentos seguintes, adição de 375 mM de sacarose ao diluidor TRIS-gema com 6,8% de glicerol (TGG), 5 minutos antes da congelação, resultou em MOT e IM similares ao controle TGG sem sacarose. Descongelação e rediluição a 4oC favoreceram a MOT e, a 38oC, favoreceram a IM. O diluente TRIS-gema com 375 mM de sacarose e concentração de glicerol reduzida para 1,7% apresentou melhor MOT e IM que o controle (65% e 187% vs 52% e 100%, respectivamente). A MOT após 2 h e o vigor após 6 h foram maiores quando a rediluição pós-descongelação foi em 5 passos se comparado a 3 passos (28% e 9% vs 19% e 2%, respectivamente). Na fase seguinte do trabalho, diluentes elaborados com 300 mM após 6 h a 38oC, melhor MOT e vigor que o controle (33% e 26% vs 15% e 10%, respectivamente). A descongelação a 20oC favoreceu a MOT e o vigor nos tempos zero, 2 h e 6 h pós-descongelação em todos os grupos contendo sacarose. O etilenoglicol não diferiu do glicerol na concentração de 3,4% quando adicionado a diluente contendo 300 mM de sacarose. Nestes diluentes, a rediluição em 5 passos a 20oC não diferiu em MOT e IM da feita em 1 passo a 38oC. No último experimento, sêmen congelado em diluente contendo 300 mM de trealose e zero% de glicerol mostrou melhor IM após descongelação em um passo a 38oC (320% vs 100% no controle) e maior MOT às 6 h após descongelação e rediluição em 5 passos a 20oC (56% vs 26% no controle). Conclui-se que o sêmen caprino tolera soluções de sacarose até o limite de 930 mOsm, mas a rediluição deve ser progressiva. A desidratação parcial, causada por soluções concentradas de sacarose ou trealose, permite a congelação de sêmen sem adição de crioprotetores permeantes. Os melhores resultados foram obtidos em diluente TRIS-gema sem glicerol e adicionado de 300 mM de trealose. / The objective of this study was to: 1) define the tolerance limits of goat sperm to hyperosmotic sucrose solutions; 2) establish an extender that minimizes cell volume variations during the processes of freezing and thawing. Boer goat semen was diluted with Ringer-lactate-Sucrose solutions at 38oC. The hyperosmotic tolerance limit was 930 mOsm evaluated with eosin-nigrosin stain. At osmolalities above this value, damage was evident after 1 min and was not affected by further exposure. Redilution in a single step resulted in massive membrane damage that was nearly proportional to the dehydration intensity previously undergone. Motility (MOT) was more distinctly impaired than membrane integrity (MI). In the next experiments, addition of 375 mM sucrose (Suc) 5 min previous to freezing to TRIS-egg yolk extender containing 6.8% glycerin (TYG) resulted in sperm motility (MOT) and MI similar to control extender TYG without sucrose. Thawing and redilution at 4oC affected favorably the MOT, and at 38oC, was favorable to MI. When freezing in TRIS-egg yolk-Suc extenders with low glycerin concentration (1.7%) MOT and MI were significantly higher than in the control TYG (65% and 187% vs 52% and 100%, respectively). MOT 2 h after thawing and intensity of motility (INTMOT) after 6 h after thawing were better preserved after a redilution of 5 increasing volume-steps than after redilution of 3 steps (28% and 9% vs 19% and 2%, respectively). In sequence, extenders containing 300 mM sucrose and thawed-rediluted 5 steps at 20oC improved MOT and INTMOT after 6 h (33% and 26% vs 15% and 10% in the control Group). The thawing-redilution at 20oC improved the results in all groups containing sucrose. At a concentration of 3.4% added to TRIS-yolk extender with 300 mM sucrose, the cryoprotectant ethylene glycol gave similar results as glycerin. MOT and INTMOT in the different time intervals were not influenced by redilution in 5 steps at 20oC or in one step at 38<SUPoC. In the last experiment made, semen frozen in a TRIS-yolk extender with 300 mM trehalose and devoid of glycerin showed the best MI after thawing-redilution in 1 step at 38oC (320% vs 100% in the control Group). The highest MOT after 6 h incubation was observed when this group was thawed-rediluted at 20oC in 5 steps (56% vs 26% in the control). From the results obtained it may be concluded that the upper tolerance limit of goat spermatozoa to hyperosmotic sucrose solutions is 930 mOsm. The redilution and return to isosmolality should be stepwise made. Goat semen can be frozen in extenders devoid of permeant cryoprotectants like glycerin when, previous to freezing, the cells are partially dehydrated by concentrated sucrose or trehalose solutions. The best survival rate was obtained when freezing goat spermatozoa in a glycerin-free TRIS-yolk-extender containing 300 mM of trehalose.

Sugar (primarily sucrose) has been a part of the daily diet for literally hundreds of years, but research is now suggesting that sugar intake can be detrimental to our health. In particular, excessive consumption of simple sugars with high glycemic index (GI) values have been shown to cause overeating and weight gain. As well, elevated postprandial hyperglycemia can result after consuming sugars and this has been linked to disease formation and progression, the development of advanced glycation endproducts, inflammation and increased mortality rates. Honey has been recognised as having a number of beneficial health properties, including slower uptake into the bloodstream, a pharmacological action of reducing blood glucose levels and a high level of bioavailable antioxidants, all of which may mean that honey could be less harmful to health than sucrose in the diet. This study was therefore designed to investigate the health benefits of honey in the diet as a replacement for sucrose, using small animal studies. As well, because of the interest in using honey as a replacement for sucrose in sweetened dairy foods, a small number of in vitro investigations were carried out to determine whether honey could retain its bioactive properties when combined with milk/dairy products. Using the in vitro studies, it was shown that the combination of milk with honey had no effect on either the antibacterial or antioxidant capabilities of honey. During the animal feeding studies a number of significant findings were observed. In the earlier work it was shown that honey had a significant effect on protein metabolism when fed for 14 days at a level of 600 g/kg diet (comprising 480 g sugars and 120 g water) compared with animals fed an equivalent amount of sucrose. In this study, honey-fed rats exhibited significantly lower weight gains (p less than 0.001), food intake (p less than 0.05) and nitrogen intakes (p less than 0.05) and significantly higher faecal nitrogen outputs (p less than 0.05) compared with sucrose-fed rats. Animals fed a diet consisting of 480 g/kg of mixed sugars as in honey generally exhibited protein metabolism parameters that were comparable to those of the sucrose-fed rats, suggesting that the effects of honey on protein metabolism were not due solely to its distinctive sugar composition. Furthermore, in another study that specifically investigated the effects of honey on weight regulation, honey (100 g/kg diet) resulted in significantly reduced weight gain after 6 weeks (p less than 0.01) compared with animals fed the same amount of sugars as sucrose, although food intake was not reduced in this study. Percentage weight gains were shown to be comparable between honey-fed rats and those fed a sugar-free diet, suggesting that differences in glycemic control may be partly responsible for the results seen. Fasting lipid profiles and blood glucose levels were also measured in this study, but no significant differences were observed between diet groups. During long-term (12 months) feeding weight gain was again significantly reduced in rats fed honey (p less than 0.05) and a sugar-free diet (p less than 0.01) compared with those fed sucrose, the weights of honey-fed rats and those fed the sugar-free diet being comparable at the end of the study. In addition, blood glucose levels were significantly lower (p less than 0.001), and HDL-cholesterol levels significantly higher (p less than 0.05) in animals fed honey compared with those fed sucrose after 52 weeks, but no differences in these parameters were observed between rats fed sucrose and a sugar-free diet. No other significant differences in lipid profiles were observed. Immunity measures were improved after feeding honey or sucrose for 52 weeks, animals in both of these diet groups having significantly higher levels of neutrophil phagocytosis compared with those fed the sugar-free diet (both p less than 0.0001). In addition, the percentage of leukocytes that were lymphocytes was significantly higher in honey-fed rats at the end of the study. Furthermore, levels of oxidative damage in aortic collagen were significantly reduced in rats fed honey or the sugar-free diet (both p less than 0.05) compared with those fed sucrose after 52 weeks. Full body DEXA scans were also undertaken in this 12-month study to assess body fat levels and bone mineral composition and density, although they revealed few statistically significant differences. Percentage body fat levels were shown to be nearly 10% lower in honey-fed rats compared with sucrose-fed animals at the end of the study (p less than 0.05), but no other significant differences between diet groups were observed. With one exception, no differences in bone mineral composition or bone mineral density were observed between the three diet groups after 52 weeks. This data agreed with the results generated from two earlier studies that showed that feeding honey short-term (for 6-8 weeks) to rats that were either calcium-deficient or fed a low calcium diet had no effect on bone calcium levels, bone mineral content, bone mineral density or bone breaking parameters. Lastly, long-term feeding of honey to rats had a number of statistically significant effects on anxiety and cognitive performance when assessed using animal maze tasks. Anxiety-like behaviour was significantly reduced in honey-fed rats overall compared with those fed sucrose (p = 0.056) or a sugar free diet (p less than 0.05). Spatial memory was also better in honey fed-rats throughout the 12 month study, these animals not displaying the same degree of age-related spatial memory loss seen in the other two diet groups. No significant differences in recognition memory or learning capability were observed between diet groups after 52 weeks. In conclusion, both short-term and long-term feeding of honey result in a number of health benefits compared with eating similar amounts of sucrose. These include less weight gain, improved immunity, reduced levels of oxidative damage and improved cognitive performance.. These effects of honey are likely to occur through a number of different processes, although the presence of high concentrations of antioxidants and other minor components in honey are likely to be important contributors. Honey may therefore help to improve human heath if it is used as an alternative to sucrose in foods and beverages, although feeding studies in humans are required to assess its efficacy. In addition, more animal studies are needed to assess which features of honey (e.g. fructose content, antioxidant content and bioactivities) are required to achieve optimal effects, and to determine what impact heating and food processing may have on the beneficial health effects of honey.

Brood pheromone of the honey bee, (Apis mellifera) has been shown to elicit a wide array of primer and releaser effects on non‐foragers and foragers leading to the regulation of nursing, pollen foraging, and behavioral development such that the behavior of the colony may be regulated by the amount and condition of the larvae. To date, all studies into the effects of brood pheromone have either used uncharacterized whole extracts or a single blend of brood pheromone characterized from a population of honey bees in France. The variation in the relative proportions of the ten fatty‐acid ester components that characterize brood pheromone and some effects of this variation on pollen foraging and sucrose response thresholds were therefore observed. The objectives met in this dissertation were to determine whether changes in brood pheromone component proportions (blend) or amount communicates larval nutritional status and reports the results of observations of nurses and foragers in response to blends of brood pheromone from deprived and‐non deprived larvae, to measure how changes in brood pheromone blend changed pollen foraging behavior and if such changes could account for the pollen foraging differences between Africanized and European bees, and finally to observe the effects of exposure time on brood pheromone blend and to observe whether non‐foragers made contact with the pheromone. Brood pheromone was found to vary by larval rearing environment, but did not elicit the expected behaviors that would support a cue of nutritional status. Brood pheromone also varied significantly by mitochondrial lineage/population source and responses to brood pheromone appeared to be coadapted to blend, suggesting that brood pheromone may be important in race recognition. Finally, brood pheromone varied significantly over time and was found to be removed from sources by bees, suggesting possible mechanisms for loss of effect. Combined the results of this research indicate that brood pheromone blend differences lead to profound changes in colony behavior related to pollen foraging and food provisioning, providing novel tools for colony manipulation and mechanisms for understanding brood rearing division of labor and chemical communication.

There is extensive research regarding the neural mechanisms that control satiety and meal termination; in contrast, there is very limited understanding of how the central nervous system regulates meal onset and thus the duration of the postprandial intermeal interval (ppIMI) and meal frequency. Based on emerging evidence, we hypothesize that dorsal hippocampal neurons, which are critical for episodic memory, form a memory of a meal and inhibit meal onset during the ppIMI. To test whether hippocampal neurons form a memory of a meal, we first determined that ingesting sucrose or isopreferred concentrations of the non-caloric sweetener saccharin increased the expression of the plasticity-related immediate early gene activity-regulated cytoskeleton-associated protein (Arc) in dorsal CA1 hippocampal (dCA1) neurons in Sprague-Dawley rats. Furthermore, repeated exposure to the sucrose meal attenuated the ability of the sucrose to induce Arc expression. Together, these data indicate that orosensory stimulation produced by a sweet taste is sufficient to induce synaptic plasticity in dCA1 neurons in an experience-dependent manner. Second, we showed that reversibly inactivating dorsal hippocampal neurons with infusions of the GABAA agonist muscimol after the end of a sucrose meal accelerated the onset of the next meal, indicating that dorsal hippocampal neurons inhibit meal onset. Lastly, using a clinically-relevant animal model of early life inflammatory injury, we found that neonatal injury (1) impairs hippocampal-dependent memory, (2) decreases the ppIMI and increases sucrose intake, (3) increases body mass, (4) attenuates sucrose-induced Arc expression in dCA1 neurons, and that (5) blocking inflammatory pain with morphine at the time of injury reverses the effects of injury on memory, energy intake and Arc expression. Collectively, the findings of this dissertation support the overarching hypothesis that dorsal hippocampal neurons inhibit meal onset during the ppIMI and suggest that dorsal hippocampal dysfunction may contribute to the development and/or maintenance of diet-induced obesity.

The easily utilized energy sources, glycerol, glucose and sucrose were used in broiler starter diets to improve growth performance. Trials investigated the effects of inclusion of easily utilized energy sources (EUES) on broiler duodenum and ileum histological developments. The effects of EUES on CHICKS delayed access to feed were investigated. In trial one, newly hatched chicks were randomly assigned to immediate (IA) or 36 hours delayed access to feed and water (DA) and fed 4 or 8% EUES during first 14 days post hatch. In trial two, males and female chicks were randomly assigned to IA or 48 hours DA, and fed 8% glycerol or glucose diets for a 14 days period. In both trials growth performance, duodenum and ileum developments were affected by dietary treatments. In conclusion, glycerol can be added into broiler starter diets up to 8%.

The main objective of this work is to propose a mechanism for the transfer of impurities into the sucrose crystal. To this end the transfer of impurities into the sucrose crystal was investigated, under crystallisation conditions similar to those found industrially. Most of the impurities, namely, colour bodies, potassium, calcium and starch, were selected on the basis of their industrial importance, but some exotic species, namely lithium and nickel, were chosen to represent other mono- and di-valent ions respectively, and dyes, such as methylene blue, which have been used in work with single crystal sucrose crystallisation, were included to make the results more general. A parameter to measure the rate at which impurities are transferred into the sucrose crystal was proposed. Experiments, carried out in a pilot plant evaporative crystalliser, were performed to establish the effect of selected factors on both the concentrations of impurities found in the sucrose crystal, and on the rate at which these impurities are incorporated into the crystal. All the factors selected, namely the rate of crystallisation, the temperature, the concentration and type of impurity, the diffusivity of the impurity in concentrated sucrose solutions, and the crystal dimensions, are shown to influence the rate of impurity transfer. Only the concentration in the feed and type of impurity, however, affect the final concentration of the impurity in the crystal. Concepts involving partition coefficients and adsorption isotherms were also investigated. The experimental data did not fit the adsorption isotherm models well, but the values obtained for the partition coefficients were similar to those quoted in the literature when exchange types of reactions are operative. Activation energies have been measured, both for the rate of crystallisation of sucrose, and for the rates of impurity transfer. The values obtained, particularly for the rate of impurity transfer, indicate that a transport mechanism is effective. The experimental results have been used to investigate the relevance of two models, one involving a two-step approach and the other an interfacial process, for the incorporation of the impurity into the sucrose crystal. The results obtained indicate that the interfacial breakdown model describes the transfer of all the impurities studied here, except for starch. / Thesis (Ph.D.)-University of Natal, Durban, 1998.

The effect of sweeteners on fruit flavor perception was studied through the use of fruitiness power functions for unsweetened and sweetened model systems. In the first part of the study, two isosweet concentrations of aspartame and sucrose were determined and combined with five concentrations of orange and strawberry flavorants. Fruitiness power functions were developed and compared to determine the effect of each sweetener on the fruit flavor. For the second part of the study in the first experiment, one isosweet concentration of sucrose, aspartame, acesulfame-K and 1:1 blended APM/Ace-K was combined with five concentrations of each of three orange flavorants. Fruitiness power functions were developed and compared to determine how each sweetener effected the fruit flavor of each flavorant. The second experiment addressed the question of whether or not subjects associated sweet taste with fruitiness or if there was an actual change in the volatile composition of the aroma between the unsweetened reference and the sweetened solutions. Fruit aroma of the middle concentration of each flavorant sweetened with the four sweeteners was compared to the corresponding unsweetened reference. Enhancement of fruitiness was observed in the aspartame sweetened systems at low flavor levels. The power function slopes of both flavorants were lowered by the addition of aspartame which resulted in a slower rate of growth in fruitiness perception with the addition of flavorant to the system. In both the orange and strawberry flavored systems the aspartame sweetened solutions were rated higher in fruitiness than the sucrose sweetened solutions. The enhancement was more pronounced in the orange flavored system, suggesting a flavorant effect. The sweeteners affected the fruitiness perception of the three orange flavorants in different magnitudes but the patterns were similar. The three fruitiness slopes were all lowered by the addition of each sweetener. Flavor enhancement was greatest in flavor 1 sweetened with aspartame or aspartame/acesulfame-K. The higher relative placement and low slope of the fruitiness power functions in aspartame sweetened systems caused the enhancement effect to be greatest over the lower concentrations of each flavorant. In the second experiment, the fruit aroma of aspartame sweetened solutions in flavor 1 was significantly higher than the other sweetened solutions. The fruit aroma of the second and third flavorants was not significantly changed by the sweeteners. / Graduation date: 1992

Bubbles in water are stabilised against coalescence by the addition of salt. The white froth in seawater but not in freshwater is an example of salt-stabilised bubbles. A range of experiments have been carried out to investigate this simple phenomenon, which is not yet understood.¶ The process of thin film drainage between two colliding bubbles relates to surface science fields including hydrodynamic flow, surface forces, and interfacial rheology. Bubble coalescence inhibition also stands alongside the better known Hofmeister series as an intriguing example of ion specificity: While some electrolytes inhibit coalescence at around 0.1M, others show no effect. The coalescence inhibition of any single electrolyte depends on the combination of cation and anion present, rather than on any single ion.¶ The surfactant-free inhibition of bubble coalescence has been studied in several systems for the first time, including aqueous mixed electrolyte solutions; solutions of biologically relevant non-electrolytes urea and sugars; and electrolyte solutions in nonaqueous solvents methanol, formamide, propylene carbonate and dimethylsulfoxide. Complementary experimental approaches include studies of terminal rise velocities of single bubbles showing that the gas-solution interface is mobile; and measurement of thin film drainage in inhibiting and non-inhibiting electrolyte solution, using the microinterferometric thin film balance technique.¶ The consolidation of these experimental approaches shows that inhibiting electrolytes act on the non-equilibrium dynamic processes of thin film drainage and rupture between bubble surfaces – and not via a change in surface forces, or by ion effects on solvent structure. In addition, inhibition is driven by osmotic effects related to solute concentration gradients, and ion charge is not important.¶ A new model is presented for electrolyte inhibition of bubble coalescence via changes to surface rheology. It is suggested that thin film stabilisation over a lifetime of seconds, is caused by damping of transient deformations of film surfaces on a sub-millisecond timescale. This reduction in surface deformability retards film drainage and delays film rupture. It is proposed that inhibiting electrolyte solutions show a dilational surface viscosity, which in turn is driven by interfacial concentration gradients. Inhibiting electrolytes have two ions that accumulate at the surface or two ions that are surface excluded, while non-inhibiting electrolytes have more evenly distributed interfacial solute. Bubble coalescence is for the first time linked through this ion surface partitioning, to the ion specificity observed at biological interfaces and the wider realm of Hofmeister effects.¶