Made available in DSpace on 2014-07-29T15:07:35Z (GMT). No. of bitstreams: 1 Dissertacao_Januaria.pdf: 2695991 bytes, checksum: fea39a26b7b89cfb880fab37ea0fafc6 (MD5) Previous issue date: 2011-02-25 / In this research, we aimed to evaluate the digestible lysine levels in pre-starter diets in the histomorphological development of 18-day embryos and newborn chicks. The performance until 21 days and dry matter digestibility and nitrogen balance in pre-starter rations and allometry of digestible and immune organs until 14 days of age. Three experiments were performed in the Avian facilities and in the Preventive Veterinary Medicine Department of the Veterinary and Animal Science College of the Federal University of Goiás, Brazil, with fertile eggs obtained from breeders in different ages and eggs with different weights at the moment of hatching. In experiment 1, effect of breeder ages and egg weights in the internal quality was evaluated during incubation period and its relation with embryo development until hatch. In experiment 2 digestible lysine supplementation in pre-starter diets for chicks hatched from eggs of different breeder ages and in experiment 3 for chicks obtained from eggs with different weights at the first day of hatching period. A total of 320 day-old chicks were allotted in each experiment in a completely randomized design and factorial arrangement 2X4 (breeder age: 34 and 52 weeks or egg weight: 56-65g and 66-72g and digestible lysine levels: 1.1; 1.2; 1.3 and 1.4%). Embryos and newborn chicks were necropsied at 18 days of incubation, at seven and 14 days after hatch, and collected samples of the small intestine (duodenum e jejunum) to prepare histological slides and gastrointestinal organs weighed. At hatch, chicks were weighed and allotted in battery cages from four to seven days of age and the metabolic assay performed in total excreta collection. Performance variables performed were final chick weight, weight gain, feed intake and ffed conversion. Nitrogen balance and nitrogen and dry matter coefficientwere calculated. Villus height and crypt depth were determined in histological sldes of duodenum and jejunum. Data were submmited to variance analysis and polynomial regression performed for digestible lysine levels. In experiment 1, breeder age and egg weight showed negative correlations with Haugh unit and positive correlation to percenual of albumen, yolk and eggshell, with embryo weight at 18 days of incubation and chick weight at hatch. In experiment 2, no interaction was observed between breeder age and digestible lysine levels in pre-starter rations. Chicks from older breeders showed better performance. In experiment 3, performance and digestibility were not affected by the increasing levels of digestible lysine in diets or egg weights at the moment of hatch. / Objetivou-se, com o presente trabalho, avaliar a suplementação de lisina digestível na ração no desenvolvimento histomorfológico de embriões com 18 dias de incubação, pintos neonatos e pintos na fase pré-inicial de produção. Avaliou-se, também, o desempenho das aves até 21 dias de idades e a digestibilidade da matéria seca e balanço de nitrogênio na fase pré-inicial e a alometria dos órgãos do aparelho digestório e sistema imune até 14 dias de vida. Realizaram-se três experimentos no Aviário Experimental e no Departamento de Medicina Veterinária Preventiva da Escola de Veterinária e Zootecnia da Universidade Federal de Goiás com ovos embrionados provenientes de matrizes com diferentes idades e ovos com diferentes pesos no início da incubação. No experimento 1, avaliou-se o efeito da idade da matriz e peso do ovo na qualidade interna dos ovos. Realizou-se a análise física dos ovos nas duas categorias em estudo (idade de matriz e peso de ovo) e durante a incubação verificou-se o desenvolvimento dos embriões até a eclosão. No experimento 2 foi avaliada a suplementação de lisina digestível em pintos de corte provenientes de matrizes com diferentes idades e no experimento 3 essa mesma suplementação foi testada em pintos de corte provenientes de ovos com diferentes pesos no momento da incubação. Foram utilizados 320 pintos para cada experimento. O delineamento experimental adotado foi DIC e esquema fatorial 2X4 (idade de matriz: 34 e 52 semanas ou peso de ovo: 56-65g e 66-72g e níveis de lisina digestível: 1,1; 1,2; 1,3 e 1,4%). Foram realizadas necropsias em embriões com 18 dias de incubação, em pintos neonatos e depois aos sete e 14 dias de vida das aves, período em que foram coletadas amostras do intestino delgado (duodeno e jejuno) para montagem de lâminas histológicas e pesagem dos órgãos do trato gastrointestinal (TGI). Ao nascimento, as aves foram pesadas e distribuídas em baterias de aço galvanizado e no período de quatro a sete dias foi realizado ensaio metabólico pelo método de coleta total de excretas. As características de desempenho avaliadas foram peso médio final, ganho de peso, consumo de ração e conversão alimentar. Foi determinado o balanço de nitrogênio, o coeficiente de digestibilidade de matéria seca e coeficiente de digestibilidade do nitrogênio. Para histomorfometria, foi verificada a altura de vilo e a profundidade de cripta do duodeno e do jejuno. Os dados foram submetidos à análise de variância e para os níveis de lisina digestível foi aplicada a regressão polinomial. No experimento 1 verificou que a idade da matriz e o peso do ovo têm correlação negativa com a unidade Haugh e correlação positiva com a porcentagem de albúmen, de gema, de casca, com o peso do embrião, com o peso do ovo aos 18 dias de incubação e com peso do pinto ao nascimento. No experimento 2 não se verificou interação entre idade da matriz e níveis crescentes de lisina na ração, os pintos provenientes de matrizes velhas apresentaram melhor desempenho. No experimento 3, o desempenho e a digestibilidade não foram afetados pelos níveis crescentes de lisina digestível na ração ou pelo peso dos ovos no momento da incubação.

As proteases fazem parte da classe de enzimas com a capacidade de hidrolisar ligaÃÃes peptÃdicas em proteÃnas e fragmentos de proteÃnas, modificando os substratos com grande seletividade e especificidade. A fermentaÃÃo semi-sÃlida à um processo fermentativo no qual o crescimento do microrganismo e a formaÃÃo dos produtos ocorrem na superfÃcie do substrato sÃlido prÃximo à ausÃncia de Ãgua livre, geralmente utilizando matÃria-prima natural como fonte de carbono e energia. Realizou-se neste estudo o cultivo semi-sÃlido de fungos filamentosos, visando à produÃÃo de proteases utilizando como substrato a torta de canola. Avaliando-se, em um primeiro estudo, o potencial de diferentes linhagens de Aspergillus para a produÃÃo de proteases. As linhagens estudadas foram Aspergillus niger (CNPAT 001, IOC 207, IOC 4222, IOC 4220 e IOC 3883) e Aspergillus oryzae IV. A melhor linhagem obtida para a produÃÃo de protease foi a linhagem de Aspergillus oryzae IV. Em seguida, estudou-se a influÃncia da adiÃÃo de diferentes volumes de Ãgua a torta, onde a melhor produÃÃo foi obtida nos meios com proporÃÃo 40 mL de Ãgua para 100 g de torta. Determinada a melhor umidade do meio, avaliou-se a temperatura de incubaÃÃo, os melhores resultados obtidos foram em meios incubados a 20ÂC. Na sequÃncia, foram feitos estudos para determinaÃÃo da melhor concentraÃÃo de inÃculo, as concentraÃÃes testas foram 1Ã104, 1Ã105, 1Ã106 e 1Ã107 esporos por grama de meio, sendo 1Ã107 a melhor concentraÃÃo analisada. Avaliou-se a influÃncia da suplementaÃÃo do meio fermentativo com fontes de fÃsforo, carbono e nitrogÃnio. A suplementaÃÃo da torta de canola, com 1% (m/m) de fosfato de sÃdio monobÃsico nÃo influenciou positivamente na produÃÃo de proteases. A suplementaÃÃo do meio com diferentes fontes de nitrogÃnio foram estudadas na proporÃÃo de 1,0 % (m/m) em relaÃÃo ao peso do substrato, sendo o extrato de levedura a melhor fonte avaliada, apresentando maior produÃÃo de proteases. Em seguida, testou-se o perÃodo de incubaÃÃo do meio sem suplementaÃÃo de nutrientes, entre 0 e 240 horas de fermentaÃÃo com amostras sendo retiradas a cada 24 h de processo fermentativo. A maior produÃÃo ocorreu em 96 h com produÃÃo de 336 U.g-1 de proteases. ApÃs esta etapa, avaliou-se a suplementaÃÃo do meio com diferentes fontes de carbono em diferentes concentraÃÃes, 1,0; 2,0; 3,0; 4,0; 5,0; 7,5; 10,0; 12,5 15,0 % (m/m) em relaÃÃo ao peso do substrato, a maior produÃÃo de proteases ocorreu no meio com adiÃÃo de glicose na concentraÃÃo de 7,5 % obtendo 452 U.g-1. Na Ãltima etapa, fez-se a caracterizaÃÃo do meio ao longo do processo fermentativo, atravÃs de determinaÃÃes analÃticas de ordem quÃmicas e fÃsico-quÃmicas. A maior produÃÃo de proteases obtida foi de 452 U.g-1 em 96 horas de processo fermentativo, nos meios suplementados com 7,5 % de glicose, nas seguintes condiÃÃes fermentativas: temperatura de incubaÃÃo do meio a 20ÂC, torta umedecida com 40 mL de Ãgua por 100 g de substrato e concentraÃÃo de inÃculo de 1Ã107 esporos.g-1. / The proteases belong to the class of enzymes with the capacity to hydrolyze peptidic connections into protein and protein fragments, modifying the substrate by great selectivity and specification. The semi-solid fermentation is a fermentation process in which the growth of microorganisms and the formation of the products occur on the surface of the solid substrate next to the absence of free water, usually using natural raw materials as a source of carbon and energy. On this study, it was done the semi solid cultivation of filament fungi, in order to produce proteases using as a substrate a cake of canola. It was evaluated, in a first study, the potential of different strains of Aspergillus for the production of proteases. The strains studied were Aspergillus niger (CNPAT 001, IOC 207, IOC 4222, IOC 4220 and IOC 3883) and Aspergillus oryzae IV. The best strain obtained for the production of protease was a strain of Aspergillus oryzae IV. Later on, it was studied the influence of the different quantities of water and coke canola added; the best production was obtained in proportion with 40 mL of water to 100 g of cake. After determination to medium of moisture, was evaluated the temperature of incubation, the best results were obtained in media incubated at 20 C. Further, studies were done to determine the best concentration of inoculum, the concentrations tested were 1 à 104, 1 à 105, 1 à 106 and 1 à 107 spores per gram of medium, being 1 à 107 to better concentration analyzed. The influence of supplementation of fermentation medium with sources of phosphorus, carbon and nitrogen was evalueted. Supplementation of the cake of canola, with 1% (w/w) monobasic sodium phosphate did not influence positively the production of proteases. Supplementation of medium with different sources of nitrogen were studied in the proportion of 1.0% (w/w) in the weight of the substrate, being the yeast extract of the best source evaluated, showing increased production of proteases. Then, it was tested the incubation period of the medium without supplementation of nutrients, between 0 and 240 hours of fermentation with samples being removed every 24 h of fermentation process. The highest production occurred at 96 h with production of 336 U.g-1 protease. After this stage, was evaluated the supplementation of medium with different carbon sources at different concentrations, 1.0, 2.0, 3.0, 4.0, 5.0, 7.5, 10.0, 12, 5 15.0 % (w/w) in the weight of the substrate; the increased production of proteases occurred in the medium with the addition of glucose at a concentration of 7.5 % obtaining 452 Ug-1. In the last stage, was performed the characterization of the medium during the fermentation process by of a chemical and physicochemical analytical determinations. The increased production of proteases obtained was 452 U.g-1 in 96 hours of fermentation process, in media supplemented with 7.5 % glucose, at the fermentation conditions: temperature of incubation of the medium at 20 C, damp cake with 40 mL water per 100 g of substrate and concentration of inoculum of 1 à 107 spores.g-1.

Made available in DSpace on 2017-07-10T17:48:25Z (GMT). No. of bitstreams: 1 Juliana_de_Souza_Oro.pdf: 1702698 bytes, checksum: eca2bb734b54448d8132976360496070 (MD5) Previous issue date: 2011-07-28 / The main aspects and the effects of CO2 levels in hatchability of day old chick was the aim of this study. The maintenance of correct levels of CO2 during all the incubation period has a benefit in the correct embryo development and growth. The study was divided in two parts: at hatchery the eggs were exposed to different levels of CO2 until Day 10 of embryo development. The experimental design was customized randomized in a factorial 2 x 4 with two breeds (Cobb 500 and Ross 308) and four levels of CO2 (4000 ppm, 6.000 ppm, 8.000 ppm e 10.000 ppm) with 8 treatments, 6 repetitions with 84 eggs each one. The second experiment was conducted to analyze the offspring performance with the same 8 treatments, 4 repetitions each one, in a total of 32 experimental units. There were 30 birds per pen. The best hatch was the 4000 ppm CO2 level and the worst was the 10000 ppm CO2 level. Cobb 500 offspring had better weight than Ross 308 at hatch moment. The moisture loss was higher at 10000 ppm CO2 level. The broiler live weight until 35 days of age was higher for 10000 and 8000 ppm CO2 level in comparison to 6000 and 4000 ppm CO2 level. In conclusion, the CO2 levels had influence at pos hatch results and broiler performance, the 4000 ppm CO2 level had the best hatch and 8000 and 10000 ppm CO2 level had the best results in broilers until 35 days of age / O objetivo desse trabalho foi avaliar a importância e os efeitos do CO2 na incubação de ovos de frango de corte. A manutenção dos níveis corretos de CO2 durante todo ciclo de incubação tem um efeito benéfico no desenvolvimento e crescimento do embrião. O trabalho foi dividido em dois experimentos: no incubatório os ovos foram submetidos a diferentes níveis de CO2 até o décimo dia de desenvolvimento embrionário. O delineamento experimental foi inteiramente casualizado em esquema fatorial 2x4 com duas linhagens (Cobb 500 e Ross 308) e quatro níveis de CO2 (4.000 ppm, 6.000 ppm, 8.000 ppm e 10.000 ppm) totalizando 8 tratamentos, com 6 repetições de 84 ovos cada. O segundo experimento consistiu em analisar o desempenho zootécnico das aves do primeiro experimento. O delineamento experimental utilizado foi inteiramente casualizado, com 8 tratamentos, 4 repetições, totalizando 32 unidades experimentais, com uma lotação de 30 aves por unidade. O total de nascimento foi maior no tratamento com o nível de 4.000 ppm de CO2 e menor no tratamento de 10.000 ppm de CO2. Os pintainhos da linhagem Cobb, no nascimento obtiveram um maior peso relativo em relação à linhagem Ross. A porcentagem de perda de umidade foi maior quando os ovos foram expostos a 10.000 ppm de CO2. O ganho de peso dos frangos até os 35 dias de vida foi maior nos tratamentos de 10.000 e 8.000 ppm em relação aos níveis 6.000 e 4.000 ppm. Pode-se concluir que níveis de CO2 influenciam nos resultados pós-eclosão e no desempenho a campo, níveis de 4.000 proporcionam uma melhor eclosão, e também que níveis com 8.000 e 10.000 ppm de CO2 resultaram em melhores resultados até os 35 dias de vida do frango de corte

Foram desenvolvidos dois experimentos para avaliação do efeito da temperatura e do período de estocagem de ovos férteis sobre os resultados da incubação, qualidade do pintinho de um dia de idade, bem como sobre o desempenho e rendimento de carcaça de frangos de corte durante as fases inicial e final. Experimento I - Utilizou-se 1620 ovos férteis da linhagem Cobb 500, oriundos de matrizes de 38 semanas de idade distribuídos em delineamento experimental inteiramente casualisado em arranjo de tratamentos em fatorial 2x2 com os fatores: período (5 e 10 dias) e temperatura (17 e 20oC) na estocagem de ovos, totalizando 4 tratamentos com nove repetições de 45 ovos cada. Após a estocagem procedeu-se a incubação em máquina de estágio único por vinte e um dias. Experimento II - Utilizou-se 504 pintos machos e fêmeas de um dia de idade, distribuídos em delineamento experimental inteiramente casualisado com os mesmos 4 tratamentos do experimento I sendo eles: Tratamento 1 (5 dias e 20oC), tratamento 2 (5 dias e 17oC), tratamento 3 (10 dias e 20oC) e tratamento 4 (10 dias e 17oC) com 9 repetições de quatorze aves cada para avaliação de desempenho e características de carcaça. Todos os dados foram analisados pelo Statistical Analysis System (SAS, 2008) e submetidos à análise de variância pelo procedimento MIXED ao nível de 5% de significância. Os dados que não respeitaram as premissas da análise estatística foram submetidos à análise não paramétrica de frequência pelo procedimento GLIMMIXED. No experimento I, não foi observado efeito significativo da interação entre os fatores analisados. Os melhores resultados de eclosão e eclodibilidade (77.28 e 77.86%, respectivamente) foram para ovos estocados por 5 dias. O efeito do período também foi observado no embriodiagnóstico, aumentando a ocorrência de mortalidade embrionária nas fases inicial e final em ovos estocados por 10 dias. A qualidade do pintinho foi superior em aves de ovos estocados durante os mesmos períodos. No experimento II, o desempenho não foi afetado significativamente pelos fatores, como também não houve efeito significativo da interação (p<0.05). Para as características de carcaça houve efeito significativo do fator temperatura (P<0,05) para peso vivo e rendimento de pernas. As aves de ovos estocados a 20oC foram mais pesadas aos 42 dias e apresentaram maior rendimento de pernas quando comparadas aos cortes de aves de ovos estocados a 17oC. Concluiu-se que a estocagem de ovos influencia os resultados da incubação bem como a qualidade do pintinho, principalmente no que diz respeito ao período em que permanecem estocados. Por outro lado o manejo pré-incubação não influenciou o desempenho de frangos de corte, mas sim características de carcaça, demonstrando que ambiência, sanidade, nutrição e melhoramento genético são fatores imprescindíveis na produção avícola mundial. / Two experiments were conducted to evaluate the effect of temperature and storage time of fertile eggs on the results of incubation, chick quality day old, as well as on the performance and carcass yield of broilers during the initial phases and final. Experiment I - was used in 1620 fertile eggs from Cobb 500, from breeders 38 weeks of age distributed in completely randomized design with treatments arranged in a 2x2 factorial with the factors: time (5 and 10 days) and temperature (17 and 20 o C) in the storage of eggs, totaling 4 treatments with nine replicates of 45 eggs each. After storage incubation proceeded in single stage machine for twenty-one days. Experiment II - was used 504 male and female chicks from one day of age in completely randomized design with 4 treatments of the same experiment I being: Treatment 1 (5 days, 20 o C), treatment 2 (5 days and 17 o C), treatment 3 (10 days and 20 o C) and treatment 4 (10 days and 17 o C) with 9 repetitions of fourteen birds each for performance evaluation and carcass characteristics. All data were analyzed using Statistical Analysis System (SAS, 2008) and subjected to analysis of variance by the MIXED procedure at the 5% significance level. Data that did not meet the assumptions of statistical analysis were analyzed by frequency nonparametric by procedure GLIMMIXED. In experiment I, there was no significant interaction between the factors. The best results hatching and hatchability (77.28 and 77.86%, respectively) were for eggs stored for 5 days. The effect of time was also observed in embryo diagnosis, increasing the occurrence of embryonic mortality in early and late in eggs stored for 10 days. Chick quality was higher in birds from eggs stored for long memos. In the second experiment, the performance was not affected by the factors, as there was no significant interaction (p <0,05). For carcass traits was no significant effect of temperature factor (P <0.05) on body weight and yield legs. Birds from eggs stored at 20 o C were heavier at 42 days and showed higher upside compared to cuts of poultry eggs stored at 17 o C. It was concluded that the storage of eggs influences the results of the incubation and chick quality, especially with regard to the period that remain stocked. On the other hand the management pre-incubation did not influence the performance of broilers, but carcass characteristics, demonstrating that ambience, sanitation, nutrition and genetic improvement are indispensable factors in poultry production worldwide.

The doubly labelled water technique was validated for captive-bred, laying Japanese quail (Coturnix coturnix), and used to measure the energy expenditure of free-living laying swallows (Hirundo rustica). Swallows had a slightly higher energy expenditure during laying than during incubation or nestling-rearing. Energy expenditure and the net cost of incubation increased sharply for female dippers (Cinclus cinclus) when clutches were enlarged to 6 eggs. Lipophilic dyes were used to determine the rate of ovarian follicular growth and the volume of yolk deposjted in a 24 h period by captive quail and free-living swallows. Rates of yolk deposition were related to daily energy expenditure in quail, but not in swallows. Balances placed under swallow nests recorded an increase in female mass from 5 d before the first egg was laid. Female mass peaked on the evening before the first egg and declined as eggs were laid. Mass changes during laying were equal to the mass of the oviduct and developing ova. However, body composition also changed, as a lipid reserve was built up in the final 4 d before the first egg was laid, whilst body water content declined. This substantially increased the peak energy requirement for biosynthesis in a laying swallow. The lipid reserve was catabolized during the remainder of the laying period. The lipid reserve was likely to serve as an insurance against a drop in food intake during laying. Shortage of food on the day before the first egg was laid led to a reduction in clutch size for some swallows. There was no evidence for use of a protein reserve by laying swallows. A model was developed from which it was predicted that egg production by swallows, and probably all other insectivorous birds, would be constrained by energy rather than crude lipid or protein requirements. It was concluded that laying patterns and clutch sizes were sometimes constrained by food availability during egg-laying, and that an upper limit to clutch size could be set by the capacity of an incubating bird to cover the eggs.

Comprendre le devenir du carbone organique stable du sol (COS) dans un environnement globalement plus chaud est un défi majeur pour prévoir sur le long terme la concentration en CO2 atmosphérique. Pour cela il apparaît nécessaire de mieux comprendre ce qu'est ce COS stable à l'échelle pluri-décennale et comment sa cinétique de minéralisation est modulée par la température. C'est avec cette ambition que cette thèse se propose (1) d'étudier la sensibilité à la température de la minéralisation du COS stable; (2) d'étudier la réponse à la température de la communauté microbienne qui minéralise le COS et (3) d'établir un lien entre âge et décomposabilité du COSLes échantillons issus de 4 essais de jachère nue ont été utilisés dans cette thèse. Des échantillons prélevés en début de chacun de ces essais et après plusieurs décennies de jachère nue ont été incubés à différentes températures pendant 427 jours. La respiration de ces échantillons a été suivie régulièrement. En fin d'incubation, la structure des communautés microbiennes a été déterminée par pyroséquençage. D'autre part, une datation du COS contenu dans les échantillons de la chrono-séquence de l'essai de jachère nue de Versailles a été réalisée.Les résultats obtenus mettent en évidence une relation générale entre vitesse de décomposition du carbone et sensibilité à la température. Ces travaux ont également mis en lumière une plus grande diversité et une plus grande sensibilité à la température des communautés microbiennes associées au carbone stable. Enfin, cette thèse met en lumière les difficultés rencontrées lors de l'utilisation de la technique de datation de la matière organique du sol par le 14C. / To understand the fate of stable soil organic carbon (SOC) in a warmer world is a major challenge to be able to predict future atmospheric CO2 concentrations. To do so, it is of prime importance to understand what the stable SOC is exactly and how its mineralization rate is modulated by temperature. This thesis proposed to study (1) the temperature sensitivity of stable SOC mineralization; (2) the response of soil microbial communities to temperature and (3) to establish a link between SOC decomposability and its age. Soil samples from four long term bare fallow experiments were used for work. We incubated soils sampled at the beggining of each experiment and after several decades of bare fallow at different temperatures for 427 days and we regularly monitored soil respiration. At the end of the incubation, soil microbial communities were assessed using pyrosequencing techniques. Finally, we determined the age of soil organic carbon by radiocarbon dating in soil samples from the chrono-sequence located at Versailles, France. The results obtained brought evidence for a general relationship between the mineralization rate of soil organic carbon and its temperature sensitivity. We also found that microbial communities linked to stable organic carbon are more diverse but also more sensitive to a temperature increase. Some bacterial phyla were particularly impacted by the temperature increase and the organic resource rarefaction. Finally, this thesis highlighted the difficulties met with the radiocarbon dating technique.

The source of a reliable supply of seed is one of the most important factors determining the success of aquaculture. At present mud crab culture is reliant on wild caught juveniles, which limits the expansion of mud crab farming globally. This, coupled with the paucity of knowledge of the spawning and egg characteristics of mud crabs, prompted the investigation into the captive spawning, incubation and egg quality of Scylla serrata in South Africa. A total of 112 mature females were caught from three estuaries in northern KwaZulu Natal and acclimated to captive conditions. Mature females were present in the estuaries throughout the year and ranged from 90 to 200 mm carapace width. Except for 40 crabs all the females spawned in captivity. On average spawning took place 38 ± 23 days after capture but was not dependent on crab size. Fecundity was significantly correlated to crab size (p = 0.026), with larger females producing more eggs. The average fecundity per batch was 5.79 ± 2.07 million eggs. Hatch success rate for all egg batches was high averaging 84 ± 6 %. Egg dropping occurred in all egg batches during incubation. On average 6.5 % of the egg mass was dropped during incubation. At the average temperature of 27⁰C eggs in the incubation system hatched within 292 ± 12 hours after extrusion. In-vitro incubation of eggs proved to be an ineffective means of incubating Scylla serrata eggs with a hatch success rate of only 25 ± 5 %. Egg quality was assessed both directly, using variables such as hatch success rate and hatch synchronicity and retrospectively by using stress tests and comparing survival of larvae from different coloured egg batches. Lipid class composition and fatty acid methyl ester content for 28 batches of eggs and 16 batches of larvae were analyzed. The biochemical composition of the egg was correlated to survival of larvae in the stress tests to ascertain if the lipid content of the eggs determines their quality. Stress tests were used to retrospectively assess egg quality. Four stressors were administered to newly hatched larvae and the LD50 values recorded. An average LD50 of 64 hours was recorded for the starvation tests, 40% for the salinity tests, 37 ppm for the formalin tests and 39.7 mg/l NH3 for the ammonia stress tests was recorded. Egg colour ranged from pale yellow to orange-red. Egg colour was not influenced by female size or the time the females spent in captivity prior to spawning. Egg colour can therefore not be used as an indicator of quality. The lipid profiles of newly extruded eggs had no effect on hatch synchronicity or hatch success rate. However, the stress tests identified female size (p ≤ 0.02), DHA content of the egg (p ≤ 0.02), Σ omega-3 fatty acids of eggs (p ≤ 0.02) and EPA content of eggs (p ≤ 0.007) as possible determinants of egg quality. Larger crabs tended to produce poorer quality eggs. Egg quality also decreased as the amount of DHA, EPA and the Σ omega-3 fatty acids decreased in the eggs. To summarize, the results of this study indicated that the following parameters affect egg quality - crab size, DHA, EPA and Σ omega-3 fatty acid content of eggs.

Confronté à la faiblesse de l’activité entrepreneuriale, le gouvernement tunisien tente de promouvoir l’impulsion d’entreprises en multipliant les mécanismes d’encouragement et d’aide des entrepreneurs. Parmi ces instruments figurent les structures d’accompagnement. Ces structures existent en Tunisie depuis 2001. Un questionnement sur leur performance et la réussite de leur intervention donc s’impose. Pour la réalisation de cette évaluation nous avons d’abord, dans une première partie, présenté l’intervention de ces structures (chapitre I), en mobilisant la théorie du capital social (chapitre II) et en faisant appel au modèle des 3 E développé par Paturel (1997) pour exposer le processus d’accompagnement (chapitre III) et le modèle des 3 F de Paturel (2007) facilitant l’introduction des critères de performance que nous avons employé (chapitre IV). Dans une deuxième, nous avons mis en oeuvre cette évaluation en adoptant une démarche éclectique combinant analyse qualitative et quantitative (chapitre I). Nos résultats nous ont poussé à conclure que les entrepreneurs tunisiens ne sont pas satisfaits de l’intervention des structures d’accompagnement tunisiennes et que seulement deux des treize structures que nous avons enquêtées sont performantes (chapitre II). En proposant une grille d’évaluation nous avons tenté de proposer quelques recommandations en fonction du profil des structures d’accompagnement afin de remédier à cette situation (chapitre III et IV). / Entrepreneurial activity is very limited in Tunisia in spite of the effort that the government is making in order to help people create their business. These efforts are implied in the development of support structures. As these structures have existed in Tunisia since 2001, we need to assess the success of their intervention. Indeed, in order to evaluate this intervention, we have, in the first part of our research, presented these structures (chapter I). We mobilized the social capital (chapter II), the 3 E mod-el’s (Paturel 1997) so as to expose the incubation process (chapter III), and also the 3 F mod-el’s (Paturel 2007) which helped us introduce the performance criteria that we used to realize this evaluation (chapter IV). In our second part, we implemented the evaluation of Tunisian support structures by adopting an eclectic approach combining a qualitative and quantitative analysis (chapter I). Our results show that Tunisian entrepreneurs aren’t satisfied with the services provided by these structures and that only two support organizations out of thirteen are prosperous (chapter II). By proposing an evaluation grid (chapter III), we tried to suggest some recommendation as a remedy for this situation (chapter IV).

The ductus arteriosi (DA) are two blood vessels connecting the pulmonary arteries to the descending aorta in the avian embryo. Following hatching, the DA closes, separation of the systemic and pulmonary circulation. I present the morphological changes that occur in the chicken DA during prepipping, internal pipping, external pipping, and hatching. The avian DA consists of two distinct tissue types, a proximal and a distal portion. Histological examination shows developmental differences between the proximal and distal portions of the DA with regard to lumen occlusion, endothelial cells, smooth muscle and elastin. Endothelial cell proliferation begins to occur as early as external pipping, with the lumen almost completely occluded by the 3rd day of post-hatching life. Expression of vascular endothelial growth factor (VEGF) increases in avian endothelial cells during hatching. I provide a morphological timeline of changes in the DA as the chicken develops from embryo to hatchling.

Developing chicken embryos have two ductus arteriosus (DA) that shunt blood away from the lungs and to the chorioallantoic membrane, the embryonic gas exchanger. In mammals, DA closure is stimulated by an increase in blood gas O2 that occurs as the animal begins to breathe with its lungs. The goal of this study was to determine the influence of O2 levels during incubation on the vascular reactivity and morphology of the O2-sensitive DA and to examine the effects of changing O2 levels during late incubation on the morphology of the DA from chicken embryos. In comparison to normoxia, hypoxia (15%) reduced venous O2 levels in day 16 and day 18 embryos and reduced aircell O2 values in day 16, day 18, and internally pipped (IP) embryos, whereas hyperoxia (30%) increased venous O2 levels and aircell O2 level in day 16, day 18, and IP embryos. In comparison to normoxia, hypoxia delayed closure of the DA, whereas hyperoxia accelerated DA closure. In comparison to the left DA from externally pipped (EP) normoxic embryos, the left DA from EP hypoxic embryos exhibited a significantly weaker contractile response to O2. The DA from day 18 hypoxic embryos exhibited a significantly weaker contractile response to norepinephrine and phenylephrine when compared with the DA from day 18 normoxic and hyperoxic embryos. The effect of incubation in hypoxia / hyperoxia during different developmental windows on the DA O2-induced contractile response was observed only in IP embryos that were incubated in normoxia for 16 days and were then moved to hyperoxia. Incubation in hypoxia / hyperoxia resulted in differences in embryo mass, yolk mass, and heart mass. There is an association between the decreased contractile response to O2 and delayed closure in the proximal portion of the DA from hypoxic embryos; as well as an increased contractile response to O2 and accelerated closure in the proximal portion of the DA from hyperoxic embryos.