Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

As leitoas são consideradas a categoria de matrizes que deve ter uma atenção especial na preparação para a vida produtiva, pois a introdução no momento certo no rebanho de produção é crucial para o desempenho e longevidade desta futura matriz. Todo período experimental deste trabalho foi realizado em uma granja produtora de leitões, localizada no Centro-Oeste do país, com capacidade de alojar 2400 fêmeas (Camborough 22®). O primeiro estudo teve como objetivo determinar se leitoas com maiores taxas de crescimento, em diferentes categorias de idade no início do estímulo à puberdade, apresentam o primeiro estro em idade mais precoce. As leitoas foram avaliadas de acordo com dois grupos de idade à exposição ao cachaço (A= 130-149 d, n= 751 e B= 150-170 d, n= 735) e de acordo com três classes de taxa de crescimento (TC) do nascimento ao início do estímulo (I = 550-649 g/d, n= 371; II= 650-725 g/d, n= 749 e III= 726- 830 g/d, n= 366). A idade no momento da exposição ao cachaço para as leitoas dos Grupos A e B foram 142,6 ± 4,9 e 157,0 ± 5,1 dias, respectivamente. No geral, em 40 dias de estimulação, 85% das leitoas foram púberes. No grupo A, leitoas da classe TCIII manifestaram maior percentual cumulativo de fêmeas em estro dentro de 10 dias (38,1 vs. 29,0 vs. 27,6%) e 20 dias de estimulação (59,7 vs. 48,7 vs. 48,2%) em comparação às classes TCII e TCI, respectivamente (P<0,05). No entanto, dentro do grupo B não houve diferença nos percentuais de fêmeas púberes entre as classes de taxa de crescimento TCIII, TCII e TCI, aos 10 dias (43,2% vs. 45,3% vs. 44,3%) e 20 dias (63,8% vs. 67,3% vs. 63,7%) após a exposição ao macho. Leitoas da classe TCIII estimuladas mais jovens (grupo A) foram mais precoces à puberdade (P<0,05) do que as de baixa taxa de crescimento (159,6 vs 164,8 dias). No entanto, a idade à puberdade não foi afetada pela taxa de crescimento, quando as leitoas foram expostas ao cachaço em idade mais avançada (grupo B). No geral, a idade à puberdade foi positivamente associada com a idade no início da exposição ao cachaço (r=0,38; P<0.0001), e o intervalo de estímulo foi menor (r= -0,19; P<0.0001) em leitoas estimuladas mais velhas. Em conclusão, a estimulação da puberdade pode ser efetuada pela exposição ao macho em idade menos avançada em leitoas com alta taxa de crescimento. O segundo estudo foi desenvolvido com o objetivo de avaliar o reflexo da taxa de crescimento e da espessura de toucinho (ET) na 1ª inseminação, sobre o desempenho subsequente da leitoa e sobre a variação de peso da leitegada ao nascimento. As leitoas foram separadas em três classes de TC do nascimento até a primeira inseminação: TCI (600-700 g/d; n= 345), TCII (701-770 g/d; n= 710) e TCIII (771-870 g/d; n= 366). As análises também foram realizadas considerando três grupos de leitoas de acordo com a ET (mm) na inseminação: ET 10-15 (n= 405), ET 16-17 (n= 649) e ET 18-23 (n= 367). Não houve diferença nas taxas de parto e retorno ao estro entre os grupos de TC e ET (P>0,05). Leitoas TCII e TCIII tiveram, respectivamente, 0,5 e 0,9 leitões a mais quando comparadas às leitoas TCI (P<0,05). Porém, leitoas TCIII apresentaram maior percentual de natimortos intra-parto (P<0,05) em comparação às leitoas das classes TCI e TCII. Leitoas da classe TCIII apresentaram maior número de leitões (P<0,05) pesando abaixo de 1.200 g ao nascimento, comparativamente às leitoas TCI. Além disso, o coeficiente de variação do peso ao nascer foi menor nas fêmeas TCI comparativamente ao das fêmeas TCII e TCIII. Leitoas TCIII apresentaram maior percentual de leitegadas com coeficiente de variação acima de 20%, comparativamente às TCI e TCII (P<0,05). Maiores números de leitões nascidos e nascidos vivos foram observados nas fêmeas do grupo ET16-17 em comparação ao grupo ET10-15 (P<0,05). Não houve diferença entre os grupos de ET no número de natimortos e nem nas variáveis relativas ao peso ao nascer dos leitões (P>0,05). Esses resultados mostram que não há vantagem, em termos de taxa de parto e número de leitões nascidos vivos, em realizar a primeira cobertura de leitoas com ganho de peso acima de 770 g/d e com mais de 17mm de ET. O terceiro estudo teve por objetivo avaliar a influência do peso da primeira inseminação sobre o desempenho reprodutivo e sobre a taxa de descarte ao longo dos três primeiros partos. As leitoas foram classificadas em três grupos, de acordo com seu peso na primeira inseminação: GI (130-150 kg, n= 298), GII (151-170 kg, n= 1007) e GIII (171-200 kg, n= 421). Leitoas do grupo GIII tiverem maior número total de leitões nascidos e maior número de natimortos (P<0,05) no primeiro parto comparativamente aos demais grupos de peso. No entanto, o número total de leitões nascidos em três partos não diferiu entre os grupos (P>0,05). Na inseminação após o primeiro desmame, houve diferença (P<0,05) na taxa de parto entre os três grupos de peso (89,3% vs. 80,3% vs. 74,9%) e a taxa de retorno ao estro foi menor no grupo GI (9,4%) do que nos grupos GII (16,4%) e GIII (19,5%). Ao final dos três partos, houve uma taxa de retenção de 66,6%. As taxas de descarte devido a problemas locomotores e por falha reprodutiva foram, respectivamente 10,8% e 11,2%. A taxa de remoção do grupo GIII (38,9%) foi maior (P= 0,006) do que no grupo GII (31,5%) e tendeu a ser maior (P= 0,06) do que no grupo GI (32,2%). A taxa de descarte devido a problemas locomotores foi superior (P<0,05) em fêmeas com maior peso na primeira inseminação (GIII) comparativamente com as dos grupos GII e GI (15,2% vs. 10,3% vs. 6,0%). Considerando que fêmeas mais pesadas apresentam maior taxa de descarte por problemas locomotores e menor taxa de retenção sem nenhuma falha reprodutiva, ao longo de três ciclos de produção, não é vantajoso realizar o primeiro acasalamento de leitoas com mais de 150 kg de peso corporal. / Gilts are regarded as the class of females that must have special attention in preparation for productive life, because the introduction at the right time in the herd of production is crucial for the future performance and longevity of this female. The studies were performed in a sow farm with capacity to accommodate 2,400 sows (Camborough 22®), located in the Midwest of Brazil (Parallel 14º). The objective of the first study was to verify whether pubertal estrus could be influenced by the growth rate and age of gilts at the onset of boar exposure. Gilts were evaluated according to two groups of age at boar exposure (A= 130-149 d, n= 751 and B= 150- 170 d, n= 735) and three classes of growth rate (Low= 550-649 g/d, n= 371; Intermediate= 650- 725 g/d, n= 749 and High= 726-830 g/d, n= 366). Gilts of groups A and B were, respectively, 142.6 ± 4.9 and 157.0 ± 5.1 days of age at the onset of boar exposure. Overall, 85% of gilts showed estrus within 40 days of boar exposure. Within group A gilts a higher (P<0.05) cumulative percentage of estrus within 10 days (38.1 vs. 29.0 vs. 27.6%) and 20 days (59.7% vs. 48.7% vs. 48.2%) of stimulation was observed in High than in Intermediate and Low growth rate gilts. Nevertheless, within group B there was no difference (P<0.05) in the percentage of estrus among High, Intermediate and Low growth rate classes within 10 days (43.2% vs. 45.3% vs. 44.3%) and 20 days (63.8% vs. 67.3% vs. 63.7%) of boar stimulation. Within group A, puberty was attained earlier (P<0.05) in High than in Low growth rate gilts (159.6 vs. 164.8 days). However, age at puberty was not affected by growth rate, when gilts were exposed to boar at an older age (group B). Overall, age at puberty was positively associated with the age at the onset of boar exposure (r= 0.38; P<0.0001) and the older the gilts were at boar exposure the lower was the interval (r= -0.19; P<0.0001) from stimulation to onset of puberty. In conclusion, successful stimulation of puberty can be obtained through an earlier exposure to boars in high growth rate gilts. The second study evaluated the influence of growth rate (GR) and backfat thickness (BF), at first mating of gilts, on the reproductive performance until the first farrowing and on the variation in birth weight of piglets. Gilts were categorized into three groups according to GR from birth until first mating: GRI (600-700 g/d, n= 345), GRII (701-770 g/d, n= 710) and GRIII (771-870 g/d, n= 366). Analyses were also performed considering three groups formed according to BF (mm) at mating: BF10-15 (n= 405); BF16-17 (n= 649) and BF18-23 (n= 367). There were no differences in farrowing rate and return to estrus rate among BF or GR groups (P>0.05). GRII and GRIII females had larger litter size compared to GRI gilts (P<0.05), respectively 0.5 and 0.9 more piglets, but a higher percentage of intrapartum stillborns (P<0.05) was observed in GRIII than in GRI and GRII females. Moreover GRIII females had more piglets (P<0.05) weighing less than 1,200 g, litters with a higher coefficient of variation for birth weight and a higher percentage of litters with coefficient of variation above 20% (P<0.05) than GRI females. More total born and born alive piglets were observed in BF16-17 compared with BF10-15 females (P<0.05).There were no differences among BF groups in number of stillborn neither in variables concerning the birth weight of piglets (P>0.05). These results show that there is no advantage, in terms of farrowing rate and number of born alive, in performing the first mating of gilts with GR >770g/d and BF >17 mm. The objective of the third study was to evaluate the influence of the weight at the first mating of gilts on the reproductive performance and on the removal rate until the third farrowing. Gilts were categorized into three groups according to weight at first mating: GI (130- 150 kg, n= 298), GII (151-170 kg, n= 1007) and GIII (171-200 kg, n= 421). In the first farrowing, GIII females had larger litter size compared to GRI and GII gilts (P<0.05), but a higher percentage of stillborns (P<0.05) also was observed in GRIII than in GRI and GRII females. However, total born over three parities were not different among groups (P>0.05). In the insemination after the first weaning, there were differences (P<0.05) in farrowing rate among all weight groups (89.3% vs. 80.3% vs. 74.9%) and return to estrus rate was lower in GI (9.4%) than in GII (16.4%) and GIII (19.5%) groups. The overall retention rate over three parities was 66.6%. Culling rate due to locomotion problems was 10.8% and due to reproductive failure was 11.2%.The removal rate over three parities in GIII females (38.9%) was higher (P= 0.006) than in GII females (31.5%) and tended to be higher (P= 0.06) than in GI females (32.2%). The culling rate due to locomotors problems was different (P<0.05) among all groups (6.0% vs. 10.3% vs. 15.2% for GI, GII and GIII, respectively). Taking into account that heavy females have higher culling rates due to locomotors disorders and lower retention rate without reproductive failure, over three productive cycles, it is not advantageous to perform the first mating of gilts with more than 150 kg of body weight.

Les surfaces de rupture par fatigue peuvent représenter les aspects complexes en fonction de: type de matériau, le mécanisme de condition de sollicitations mécaniques, environnement ambiant etc.Dans le cadre des chargements complexes ou variables les surfaces de rupture sont encore plus difficiles à analyser, car de telles sollicitations peuvent engendrer les changements de mécanismes dans certains matériaux.Dans le cadre de changements variables, l'une des questions importantes est la connaissance de la vitesse de croissance des fissures.Des techniques actuelles de mesures de vitesse font appel aux mesures optiques ou aux mesures indirectes de mesures de la cinétique de croissance de fissures.Une méthode élégante consiste à faire des cycles marqueurs qui permettent de laisser une marque sur la surface de rupture que l'on ensuite identifier par analyse au microscope à balayage.A cette fin on peut utiliser : - les petites surcharges, les sous charges, les cycles en dessous du seuil de non propagation, un changement de température etc.Le but de travail de thèse serait de développer les cycles marqueurs sur trois matériaux:un alliage d'aluminium, un acier et un caoutchouc synthétique.L'idée étant de développer des cycles de marquage sans modifier le cinétique de propagation.Les essais comparatifs de fissuration seront menés avec ou sans cycles de marquage pour vérifier cette hypothèse.Le travail expérimental sera effectué au LMR (machine de fatigue) ainsi que l'analyse MEB. / The fracture surfaces of fatigue can represent complex aspects according to:type of material, provided mechanism of mechanical stresses, ambient environment, etc.Under complex loadings or variable ones, fracture surfaces are more difficult to analyze because such changes can cause change in mechanisms in certain materials.Under variable amplitudes, one of the important issues is the knowledge of the crack growth rate.Current techniques involve optical measurements or indirect ones that measures the kinetics of crack growth.An elegant method is to generate marker bands that can leave a mark on the fracture surface which is then identified by scanning electron microscope analysis.For this purpose one can use: - small overload, under load, cycles below the threshold, a change of temperature, etc.The aim of this thesis is to develop the technique of marker bands on three materials:an aluminum alloy, steel and synthetic rubber.The idea is to develop this technique without changing the propagation kinetics.The experiments will be conducted by fatigue cracking with or without marking marker bands to test this hypothesis.The experimental work has been carried out in LMR laboratory.

Silification and growth rates of diatoms were measured at three spatially distinct sampling sites in the Římov Reservoir in 2011. Silica deposition measured via PDMPO fluorescence technique was significantly related to growth rates of three dominant diatom species (Fragilaria crotonensis, Asterionella formosa, Aulacoseira italica). Over the study season, light has a decisive effect on diatom growth, which was the highest at the transition zone of the reservoir.

As leitoas são consideradas a categoria de matrizes que deve ter uma atenção especial na preparação para a vida produtiva, pois a introdução no momento certo no rebanho de produção é crucial para o desempenho e longevidade desta futura matriz. Todo período experimental deste trabalho foi realizado em uma granja produtora de leitões, localizada no Centro-Oeste do país, com capacidade de alojar 2400 fêmeas (Camborough 22®). O primeiro estudo teve como objetivo determinar se leitoas com maiores taxas de crescimento, em diferentes categorias de idade no início do estímulo à puberdade, apresentam o primeiro estro em idade mais precoce. As leitoas foram avaliadas de acordo com dois grupos de idade à exposição ao cachaço (A= 130-149 d, n= 751 e B= 150-170 d, n= 735) e de acordo com três classes de taxa de crescimento (TC) do nascimento ao início do estímulo (I = 550-649 g/d, n= 371; II= 650-725 g/d, n= 749 e III= 726- 830 g/d, n= 366). A idade no momento da exposição ao cachaço para as leitoas dos Grupos A e B foram 142,6 ± 4,9 e 157,0 ± 5,1 dias, respectivamente. No geral, em 40 dias de estimulação, 85% das leitoas foram púberes. No grupo A, leitoas da classe TCIII manifestaram maior percentual cumulativo de fêmeas em estro dentro de 10 dias (38,1 vs. 29,0 vs. 27,6%) e 20 dias de estimulação (59,7 vs. 48,7 vs. 48,2%) em comparação às classes TCII e TCI, respectivamente (P<0,05). No entanto, dentro do grupo B não houve diferença nos percentuais de fêmeas púberes entre as classes de taxa de crescimento TCIII, TCII e TCI, aos 10 dias (43,2% vs. 45,3% vs. 44,3%) e 20 dias (63,8% vs. 67,3% vs. 63,7%) após a exposição ao macho. Leitoas da classe TCIII estimuladas mais jovens (grupo A) foram mais precoces à puberdade (P<0,05) do que as de baixa taxa de crescimento (159,6 vs 164,8 dias). No entanto, a idade à puberdade não foi afetada pela taxa de crescimento, quando as leitoas foram expostas ao cachaço em idade mais avançada (grupo B). No geral, a idade à puberdade foi positivamente associada com a idade no início da exposição ao cachaço (r=0,38; P<0.0001), e o intervalo de estímulo foi menor (r= -0,19; P<0.0001) em leitoas estimuladas mais velhas. Em conclusão, a estimulação da puberdade pode ser efetuada pela exposição ao macho em idade menos avançada em leitoas com alta taxa de crescimento. O segundo estudo foi desenvolvido com o objetivo de avaliar o reflexo da taxa de crescimento e da espessura de toucinho (ET) na 1ª inseminação, sobre o desempenho subsequente da leitoa e sobre a variação de peso da leitegada ao nascimento. As leitoas foram separadas em três classes de TC do nascimento até a primeira inseminação: TCI (600-700 g/d; n= 345), TCII (701-770 g/d; n= 710) e TCIII (771-870 g/d; n= 366). As análises também foram realizadas considerando três grupos de leitoas de acordo com a ET (mm) na inseminação: ET 10-15 (n= 405), ET 16-17 (n= 649) e ET 18-23 (n= 367). Não houve diferença nas taxas de parto e retorno ao estro entre os grupos de TC e ET (P>0,05). Leitoas TCII e TCIII tiveram, respectivamente, 0,5 e 0,9 leitões a mais quando comparadas às leitoas TCI (P<0,05). Porém, leitoas TCIII apresentaram maior percentual de natimortos intra-parto (P<0,05) em comparação às leitoas das classes TCI e TCII. Leitoas da classe TCIII apresentaram maior número de leitões (P<0,05) pesando abaixo de 1.200 g ao nascimento, comparativamente às leitoas TCI. Além disso, o coeficiente de variação do peso ao nascer foi menor nas fêmeas TCI comparativamente ao das fêmeas TCII e TCIII. Leitoas TCIII apresentaram maior percentual de leitegadas com coeficiente de variação acima de 20%, comparativamente às TCI e TCII (P<0,05). Maiores números de leitões nascidos e nascidos vivos foram observados nas fêmeas do grupo ET16-17 em comparação ao grupo ET10-15 (P<0,05). Não houve diferença entre os grupos de ET no número de natimortos e nem nas variáveis relativas ao peso ao nascer dos leitões (P>0,05). Esses resultados mostram que não há vantagem, em termos de taxa de parto e número de leitões nascidos vivos, em realizar a primeira cobertura de leitoas com ganho de peso acima de 770 g/d e com mais de 17mm de ET. O terceiro estudo teve por objetivo avaliar a influência do peso da primeira inseminação sobre o desempenho reprodutivo e sobre a taxa de descarte ao longo dos três primeiros partos. As leitoas foram classificadas em três grupos, de acordo com seu peso na primeira inseminação: GI (130-150 kg, n= 298), GII (151-170 kg, n= 1007) e GIII (171-200 kg, n= 421). Leitoas do grupo GIII tiverem maior número total de leitões nascidos e maior número de natimortos (P<0,05) no primeiro parto comparativamente aos demais grupos de peso. No entanto, o número total de leitões nascidos em três partos não diferiu entre os grupos (P>0,05). Na inseminação após o primeiro desmame, houve diferença (P<0,05) na taxa de parto entre os três grupos de peso (89,3% vs. 80,3% vs. 74,9%) e a taxa de retorno ao estro foi menor no grupo GI (9,4%) do que nos grupos GII (16,4%) e GIII (19,5%). Ao final dos três partos, houve uma taxa de retenção de 66,6%. As taxas de descarte devido a problemas locomotores e por falha reprodutiva foram, respectivamente 10,8% e 11,2%. A taxa de remoção do grupo GIII (38,9%) foi maior (P= 0,006) do que no grupo GII (31,5%) e tendeu a ser maior (P= 0,06) do que no grupo GI (32,2%). A taxa de descarte devido a problemas locomotores foi superior (P<0,05) em fêmeas com maior peso na primeira inseminação (GIII) comparativamente com as dos grupos GII e GI (15,2% vs. 10,3% vs. 6,0%). Considerando que fêmeas mais pesadas apresentam maior taxa de descarte por problemas locomotores e menor taxa de retenção sem nenhuma falha reprodutiva, ao longo de três ciclos de produção, não é vantajoso realizar o primeiro acasalamento de leitoas com mais de 150 kg de peso corporal. / Gilts are regarded as the class of females that must have special attention in preparation for productive life, because the introduction at the right time in the herd of production is crucial for the future performance and longevity of this female. The studies were performed in a sow farm with capacity to accommodate 2,400 sows (Camborough 22®), located in the Midwest of Brazil (Parallel 14º). The objective of the first study was to verify whether pubertal estrus could be influenced by the growth rate and age of gilts at the onset of boar exposure. Gilts were evaluated according to two groups of age at boar exposure (A= 130-149 d, n= 751 and B= 150- 170 d, n= 735) and three classes of growth rate (Low= 550-649 g/d, n= 371; Intermediate= 650- 725 g/d, n= 749 and High= 726-830 g/d, n= 366). Gilts of groups A and B were, respectively, 142.6 ± 4.9 and 157.0 ± 5.1 days of age at the onset of boar exposure. Overall, 85% of gilts showed estrus within 40 days of boar exposure. Within group A gilts a higher (P<0.05) cumulative percentage of estrus within 10 days (38.1 vs. 29.0 vs. 27.6%) and 20 days (59.7% vs. 48.7% vs. 48.2%) of stimulation was observed in High than in Intermediate and Low growth rate gilts. Nevertheless, within group B there was no difference (P<0.05) in the percentage of estrus among High, Intermediate and Low growth rate classes within 10 days (43.2% vs. 45.3% vs. 44.3%) and 20 days (63.8% vs. 67.3% vs. 63.7%) of boar stimulation. Within group A, puberty was attained earlier (P<0.05) in High than in Low growth rate gilts (159.6 vs. 164.8 days). However, age at puberty was not affected by growth rate, when gilts were exposed to boar at an older age (group B). Overall, age at puberty was positively associated with the age at the onset of boar exposure (r= 0.38; P<0.0001) and the older the gilts were at boar exposure the lower was the interval (r= -0.19; P<0.0001) from stimulation to onset of puberty. In conclusion, successful stimulation of puberty can be obtained through an earlier exposure to boars in high growth rate gilts. The second study evaluated the influence of growth rate (GR) and backfat thickness (BF), at first mating of gilts, on the reproductive performance until the first farrowing and on the variation in birth weight of piglets. Gilts were categorized into three groups according to GR from birth until first mating: GRI (600-700 g/d, n= 345), GRII (701-770 g/d, n= 710) and GRIII (771-870 g/d, n= 366). Analyses were also performed considering three groups formed according to BF (mm) at mating: BF10-15 (n= 405); BF16-17 (n= 649) and BF18-23 (n= 367). There were no differences in farrowing rate and return to estrus rate among BF or GR groups (P>0.05). GRII and GRIII females had larger litter size compared to GRI gilts (P<0.05), respectively 0.5 and 0.9 more piglets, but a higher percentage of intrapartum stillborns (P<0.05) was observed in GRIII than in GRI and GRII females. Moreover GRIII females had more piglets (P<0.05) weighing less than 1,200 g, litters with a higher coefficient of variation for birth weight and a higher percentage of litters with coefficient of variation above 20% (P<0.05) than GRI females. More total born and born alive piglets were observed in BF16-17 compared with BF10-15 females (P<0.05).There were no differences among BF groups in number of stillborn neither in variables concerning the birth weight of piglets (P>0.05). These results show that there is no advantage, in terms of farrowing rate and number of born alive, in performing the first mating of gilts with GR >770g/d and BF >17 mm. The objective of the third study was to evaluate the influence of the weight at the first mating of gilts on the reproductive performance and on the removal rate until the third farrowing. Gilts were categorized into three groups according to weight at first mating: GI (130- 150 kg, n= 298), GII (151-170 kg, n= 1007) and GIII (171-200 kg, n= 421). In the first farrowing, GIII females had larger litter size compared to GRI and GII gilts (P<0.05), but a higher percentage of stillborns (P<0.05) also was observed in GRIII than in GRI and GRII females. However, total born over three parities were not different among groups (P>0.05). In the insemination after the first weaning, there were differences (P<0.05) in farrowing rate among all weight groups (89.3% vs. 80.3% vs. 74.9%) and return to estrus rate was lower in GI (9.4%) than in GII (16.4%) and GIII (19.5%) groups. The overall retention rate over three parities was 66.6%. Culling rate due to locomotion problems was 10.8% and due to reproductive failure was 11.2%.The removal rate over three parities in GIII females (38.9%) was higher (P= 0.006) than in GII females (31.5%) and tended to be higher (P= 0.06) than in GI females (32.2%). The culling rate due to locomotors problems was different (P<0.05) among all groups (6.0% vs. 10.3% vs. 15.2% for GI, GII and GIII, respectively). Taking into account that heavy females have higher culling rates due to locomotors disorders and lower retention rate without reproductive failure, over three productive cycles, it is not advantageous to perform the first mating of gilts with more than 150 kg of body weight.

In my thesis I present data collected from a long-term selection experiment using the freshwater model organism Chlamydomonas reinhardtii. The selection experiment was designed to disentangle the effects of the number of multiple environmental drivers (MEDs) and the identity of those environmental drivers including high CO2, high temperature, general nutrient depletion, reduced light intensity, reduced phosphate availability, the addition of a herbicide, UV radiation and reduced pH. Using up to eight environmental drivers, I show how simple organisms such as C. reinhardtii evolve in response to MEDs. The first step in this investigation is to examine the short-term response of MEDs. Data collected at the beginning of the selection experiment will provide insight into the early stages of microevolution by investigating key differences in the short-term (plastic) responses to few vs. many MEDs. Here, I focus on how the data collected from the responses to single environmental drivers can help us predict the responses to MEDs by using ecological models (additive, comparative, multiplicative). I show that the short-term plastic responses to single environmental drivers can predict the effect of MEDs using the comparative model because the response is largely driven by the single dominant driver present. I also demonstrate the importance of the number of environmental drivers (NED) for making predictions from the single environmental drivers and show that predictions become more reliable as the NED increases. The results gathered from short-term responses provide evidence that single environmental driver studies are useful for predicting the effect of MEDs. After evolution, I found that the strength of selection varies with NED in a predictable way, which connects the NED to the evolutionary response (size of the direct response) through the strength of selection. Here, I used statistical models to quantify the effect of NED on the evolutionary response to MEDs and then interpreted this by considering the possible genetic constraints on adaptation to MEDs. A subset of populations evolved in environments with five environmental drivers and all populations evolved in the single environmental driver environments are used to examine how adapting to single vs. many environmental drivers affect local adaptation. I examine how populations selected in environments with one environmental driver, five environmental drivers and the evolved control, differ in their response to new environments with the same NED, environments with different NED, and a novel environment. I found that there is a relationship between local adaptation and the strength of selection in the local environment and patterns of local adaptation are affected by the NED of new environments. Lastly, I present the phenotypic consequences of evolution under MEDs. I found that before evolution, measures of chlorophyll content and cell size decline with increasing NED. However, after evolution the relationship between chlorophyll content and cell size with NED is weaker because populations converge on the same phenotypes as they evolve. I also present a case-study of how mass spectrometry methods can be used to better understand underlying molecular mechanisms of two phenotypes (chlorophyll positive and chlorophyll negative cells). This selection experiment is a good example of how laboratory investigations and model organisms can be used to design experiments with enough replication to have high statistical power in order to make more accurate predictions on the short- long-term effects of MEDs. Whilst there have been some studies on the effects of MEDs, these studies rarely have more than three environmental drivers (sometimes 5 environmental drivers) and there are only a handful of long-term MED studies. This study can be used to develop a priori hypotheses for investigating how environmental change will shape natural microbial communities, and is especially useful for organisms where long-term studies with multiple environmental drivers are unfeasible.

Elucidating the factors that drive variation in the abundance and distribution of organisms is central to ecology. Variables that explain the spatial variation in the abundance of organisms primarily include environmental (e.g., temperature and precipitation) and biotic factors (e.g., competition, predation, and parasitism). An important mechanism influencing the spatial distribution of organisms, at least at small spatial scales, is habitat selection. Traditionally, habitat selection theory has assumed that animals select habitat based on their ability to acquire depletable resources within that habitat, especially food. Ectotherms, however, may instead select habitat based on their ability to process food within the habitat, given the strong dependence of body temperature (and performance) on environmental temperature in this group. The major objective of my thesis was to determine whether energy gain, habitat selection, and population density were driven primarily by food availability or by temperature in ectotherms. I used Sceloporus jarrovii lizards as a study species because these lizards occur at high densities and in similar habitat across a broad altitudinal range. In Chapter 1, I tested the prediction, central to the thermal coadaptation hypothesis, that juvenile lizards prefer body temperatures that maximize their net energy gain. I also tested whether lizards shifted their preferred body temperatures to correspond to the optimal temperature for different energetic states, as per Huey’s (1982) energetics model. In Chapter 2, I determined whether the home range size and density of lizards shifted in response to manipulations of food availability and/or thermal quality within a site. In Chapters 3 and 4, I determined whether mean body condition, individual growth rate, and population density were driven by food availability or thermal quality. In Chapter 3, I visited 32 study sites over a 1,550 m altitudinal range within a year; whereas in Chapter 4, I food-supplemented five out of 10 study sites where I performed mark-recapture over a period of three years. Overall, my thesis demonstrates that both food availability and thermal quality of the habitat drive energy gain, habitat selection, and population density. Juvenile S. jarrovii preferred body temperatures that maximized net energy gain, regardless of energetic state. Although they did not shift their preferred body temperature range depending on energetic state, the difference in the optimal temperature for net energy gain between states (0.4°C), may have been too small to warrant a change in behaviour. Within a site, S. jarrovii increased their home range size and occurred at higher densities as natural food availability increased, and decreased their home range size and occurred at lower densities as the thermal quality under the rocks increased. This suggests that S. jarrovii respond to food availability and thermal quality at different scales, selecting territories based on thermal quality and home ranges based on food availability. Over 32 sites, the abundance of S. jarrovii increased with food availability, whereas the mean body condition increased and the rate at which lizards attained their maximum body size decreased with elevation (at lower thermal quality). In the three-year study, mean body condition and individual growth rate decreased and population density increased with thermal quality, but the strength of the relationship depended on natural food availability. Overall, both food availability and thermal quality of the habitat drive energy gain, habitat selection, and population density; however, thermal quality is often the stronger driver. Thus, improvements to habitat selection models should incorporate habitat thermal quality to improve predictions on how ectotherms distribute themselves on a landscape.

Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-01Bitstream added on 2014-06-13T18:52:30Z : No. of bitstreams: 1 assuncao_ica_me_botfca.pdf: 943075 bytes, checksum: ce539ad58264cbbab2e1e863aae2d636 (MD5) / Universidade Estadual Paulista (UNESP) / Um ensaio, com amendoim (Arachis hypogaea L.), cv. IAC-TATUST, foi conduzido, na área experimental do Setor de Ciências Ambientais (21,85° S; 48,43° W; 786 m), FCA/UNESP, em Botucatu, SP, em parcela única sob tratamento úmido durante o período de 11/02/2001 a 06/06/2001. Durante todas as fases de crescimento das plantas foram monitoradas as radiações fotossinteticamente ativa incidente, refletida e transmitida, bem como a produção semanal da biomassa acumulada e sua energia química, incluindo raízes, hastes, folhas, flores, frutos e sementes, com o objetivo de determinar a eficiência de uso da radiação (EUR) e a eficiência de conversão da radiação interceptada (ECR) pelas plantas cultivadas. Os resultados mostraram que a EUR média foi de 1,33 g MJ-1 e a ECR foi de 2,5%, cujos valores estão coerentes com aqueles encontrados em literatura. Nas condições de Botucatu, a cultura do amendoim interceptou, aproximadamente 600 MJ m-2 de radiação PAR, de modo que no final do seu ciclo a energia da biomassa atingiu a magnitude de 18 MJ m-2. Em termos médios, o coeficiente de extinção da luz (k) foi de 0,68, o índice de colheita, em base de energia, foi de 0,38 e a produtividade obtida, do amendoim em casca, foi equivalente a 4,5 t ha-£. / A trial, with peanut (Arachis hypogaea L.), cv. IAC-TATU-ST, was carried out, in experimental area of Setor de Ciências Ambientais (21,85° S; 48,43° W; 786 m), FCA/UNESP, in Botucatu, SP, in single section with humid treatment during the period from 11/02/2001 to 06/06/2001. For all growth phases of peanut crop, the incident, reflected and transmitted photosynthetically active radiations were monitored, as well as the weekly production of the accumulated biomass, chemical energy, including roots, stems, leaves, flowers, fruits and seeds, with purpose of determining the radiation use efficiency and the radiation conversion efficiency of intercepted PAR for the cultivated plants. The results showed that EUR was about 1,33 g MJ-1 and ECR was about 2,5%. The values are coherent with those found in literature. In Botucatu conditions, the peanut crop intercepted, more or less 600 MJ m-2 of PAR, so that in the end of cycle, the biomass energy reached to 18 MJ m-2. In standard terms, the light extinction coefficient (k) was about 0.68, the harvest index, in energy basis, was about 0.38 and peanut yield, in peel, was equivalent to 4.5 t ha-£.

Orientador: Dinival Martins / Banca: Raimundo Leite Cruz / Banca: Emerson Galvani / Resumo: Um ensaio, com amendoim (Arachis hypogaea L.), cv. IAC-TATUST, foi conduzido, na área experimental do Setor de Ciências Ambientais (21,85° S; 48,43° W; 786 m), FCA/UNESP, em Botucatu, SP, em parcela única sob "tratamento úmido" durante o período de 11/02/2001 a 06/06/2001. Durante todas as fases de crescimento das plantas foram monitoradas as radiações fotossinteticamente ativa incidente, refletida e transmitida, bem como a produção semanal da biomassa acumulada e sua energia química, incluindo raízes, hastes, folhas, flores, frutos e sementes, com o objetivo de determinar a eficiência de uso da radiação (EUR) e a eficiência de conversão da radiação interceptada (ECR) pelas plantas cultivadas. Os resultados mostraram que a EUR média foi de 1,33 g MJ-1 e a ECR foi de 2,5%, cujos valores estão coerentes com aqueles encontrados em literatura. Nas condições de Botucatu, a cultura do amendoim interceptou, aproximadamente 600 MJ m-2 de radiação PAR, de modo que no final do seu ciclo a energia da biomassa atingiu a magnitude de 18 MJ m-2. Em termos médios, o coeficiente de extinção da luz (k) foi de 0,68, o índice de colheita, em base de energia, foi de 0,38 e a produtividade obtida, do amendoim em casca, foi equivalente a 4,5 t ha-£. / Abstract: A trial, with peanut (Arachis hypogaea L.), cv. IAC-TATU-ST, was carried out, in experimental area of Setor de Ciências Ambientais (21,85° S; 48,43° W; 786 m), FCA/UNESP, in Botucatu, SP, in single section with "humid treatment" during the period from 11/02/2001 to 06/06/2001. For all growth phases of peanut crop, the incident, reflected and transmitted photosynthetically active radiations were monitored, as well as the weekly production of the accumulated biomass, chemical energy, including roots, stems, leaves, flowers, fruits and seeds, with purpose of determining the radiation use efficiency and the radiation conversion efficiency of intercepted PAR for the cultivated plants. The results showed that EUR was about 1,33 g MJ-1 and ECR was about 2,5%. The values are coherent with those found in literature. In Botucatu conditions, the peanut crop intercepted, more or less 600 MJ m-2 of PAR, so that in the end of cycle, the biomass energy reached to 18 MJ m-2. In standard terms, the light extinction coefficient (k) was about 0.68, the harvest index, in energy basis, was about 0.38 and peanut yield, in peel, was equivalent to 4.5 t ha-£. / Mestre