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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Effect of nutrient concentration and growing seasons on growth, yield and quality of leafy lettuce (Lactuca sativa L.) in a hydroponic system

Chiloane, Thikanang Silence 25 June 2013 (has links)
Lettuce is becoming an increasingly important vegetable, both as a fresh market product and a ready-to use vegetable, especially in urban areas of South Africa. Nutrient solution concentration is one of the most practical and effective ways of controlling and improving the yield and nutritional quality of crops for human consumption. However, optimal fertilizer concentration for leafy vegetables also depends on the prevailing environmental conditions. This study was carried out to determine the effects of different nutrient solution concentrations and growing seasons on growth, yield and quality of leafy lettuce. The trial was conducted in a black and white shade net structure and the nutrient concentration treatments were 1.0, 2.0, 3.0, and 4.0 mS.cm-1. Measurements taken included: leaf number, leaf area, fresh leaf mass, dry leaf mass, dry root mass, as well as chlorophyll content. The sensory evaluation procedure was only done on plant samples grown during summer and winter seasons. The results showed that growth was less affected by nutrient concentration than by growing season. Regardless of the nutrient concentration, plants grown in summer reached maturity quicker as compared to plants grown in winter. Generally, leaf number, leaf area, leaf area index, fresh leaf mass, dry leaf mass and dry root mass did not significantly increase with increasing nutrient concentrations and therefore, yield was not influenced by nutrient concentrations. Quality was influenced by nutrient concentrations during the summer-autumn seasons where increasing nutrient concentration induced increased chlorophyll content of the leaves. During the winter-spring seasons this phenomenon was not significant. The study demonstrated that growth, yield and quality of lettuce were not significantly influenced by nutrient solution concentrations of 1.0, 2.0, 3.0 and 4.0 mS.cm-1. The sensory evaluation also showed no significant differences on the colour (quality) and flavor of the lettuce samples grown during summer and winter seasons and unfortunately it was not done during autumn and spring seasons. Irrespective of the nutrient solution concentration, growth was influenced by growing season because plants grown during summer reached maturity quicker as compared to plants grown during the other seasons. / Dissertation (MInstAgrar)--University of Pretoria, 2012. / Plant Production and Soil Science / unrestricted
62

Variation of active constituents in Euclea natalensis based on seedling stages, seasons, and fertilizers

Bapela, Mahwahwatse Johanna 26 June 2008 (has links)
Euclea natalensis A.DC. belongs to the Ebenaceae family, and is extensively distributed along the eastern coast of southern Africa. Many Euclea species are widely gathered by indigenous people because of their medicinal properties. Roots of these plant species are frequently used to treat respiratory complications such as chest pains, bronchitis, pleurisy and asthma. Ground root powder is topically applied in cases of leprosy and is used by some ethnic groups to treat toothache and headache. The bioactivity encountered is attributable to naphthoquinones, which are common phenolic compounds in the Ebenaceae family. Naphthoquinones isolated from E. natalensis (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) have exhibited a broad spectrum of antimicrobial activity. The demand for these products will escalate due the amount of plant material required to further research. We need to explore techniques that can maximize their productivity. The present study was conducted on E. natalensis, in an attempt to establish if there exists any correlation between the accumulation of naphthoquinones and stages of seedling growth, seasonal fluctuations and application of fertilizers. A possible correlation between seedling growth stages and the accumulation of naphthoquinones (shinanolone, 7-methyljuglone and diospyrin) was investigated in seeds and seedlings of Euclea natalensis. In this study, the seeds represented the first stage, whereas the second seedling stage was defined as the stage when the radicles were about 6 cm long. The lengths of the seedlings at the third, fourth and fifth seedling stages were 9 cm, 12 cm and 16 cm respectively. Plant materials collected from the five seedling stages were separately extracted using chloroform and the naphthoquinones were then quantified by means of High Performance Liquid Chromatography (HPLC). Mobile phase of MeCN: H2O: AcOH (62.5: 32.5: 5) was used as an eluent in an isocratic mode and at a flow rate of 0.8 ml/min. Standard curves of each of the four compounds were obtained by making a series of dilutions in the concentration range of 22.5 µg/ml to 2.25 µg/ml. Ten microlitres of each dilution was injected three times into the HPLC, and the run time for each injection was 20 minutes. Calibration curves were then generated and used for the quantification of each compound. Shinanolone, which was the only naphthoquinone detectible in seeds, accumulated at variable rates (P<0.01) and no trend could be established between its synthesis and seedling growth. The content of shinanolone ranged from 87.5 mg/kg dry weight (dw) in seeds to a high mean value of 1047 mg/kg (dw) during the fourth seedling stage. A significant correlation (P<0.01) was found between the mean concentrations of 7-methyljuglone and seedling growth. 7-Methyljuglone was quantified at a high mean level of 5003 mg/kg during the third seedling stage and was not detected in the seed samples. A positive correlation (P<0.01) was established between the concentration of diospyrin and seedling stages. Diospyrin was detected at an elevated mean concentration of 6182 mg/kg during the fifth seedling stage, which was higher than the other quantified naphthoquinones. Seasonal variation of naphthoquinones (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) was investigated from eleven plants of E. natalensis subsp. natalensis growing in natural populations, over a period of four seasons. The roots were harvested, dried, extracted and analysed as in the previous study. The mean levels of shinanolone and 7-methyljuglone were found to be uniform in all the seasons and no statistically significant variation could be found between seasonal changes and their mean concentrations. Accumulation of isodiospyrin and neodiospyrin varied significantly with seasonal changes (P<0.05). These two bioactive naphthoquinones were detected only in summer and autumn respectively, and not in winter. A statistically significant variation (P<0.05) was established between the levels of diospyrin and seasonal fluctuations. Diospyrin was detected at a mean concentration of 3190 mg/kg (dw) during spring, which was higher than the other naphthoquinones quantified in all four seasons. The effect of NPK fertilizers on growth performance and accumulation of naphthoquinones (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) in seedlings of E. natalensis grown in shade and under field conditions was investigated. Each group was subdivided into four subgroups, which were then subjected to four respective treatments of water-soluble foliar feed (2:1:2 (44) NPK) at three different concentrations. Treatments tested were as follows: Treatment 1 at 40 g/l, Treatment 2 and Treatment 3 at 20 g/l and 10 g/l respectively. The control group received only supplemental water. The first harvest was conducted after 6 months of application of fertilizers and the second one was done after 12 months of treatment. Roots and shoots were harvested and analysed separately. The naphthoquinones were quantified as previously described. The bioactivity of root extracts from seedlings was tested against Mycobacterium smegmatis and extracts with lower MIC were further tested on M. tuberculosis. Growth parameters differed between the two groups, with seedlings from the shadehouse showing more plant vigour than the field grown plants. No significant interaction could be established between the measured growth factors and treatment. A significant interaction (P<0.001) was found between Treatment 2 and shadehouse seedlings. Treatment 2 enhanced vegetative performance with the mean values of fresh weight of shoots and roots being twice as much as their respective control mean values. A significantly positive correlation was established between the concentration of shinanolone (P<0.01), isodiospyrin (P<0.05) and neodiospyrin (P<0.05) with fertilization from field-grown seedlings. Application of NPK fertilizers significantly (P<0.05) increased the accumulation of neodiospyrin in seedlings subjected to shadehouse conditions. The most potent naphthoquinone, 7-methyljuglone, was found to be abundant in all the extracts and was quantified at a high mean concentration of 10200 mg/kg from shadehouse seedlings. Root extracts of E. natalensis seedlings grown under field conditions were generally more active against the bacterial strain of M. smegmatis as compared to extracts acquired from roots of seedlings maintained under a shadehouse setting. A lowest minimum inhibitory concentration (MIC) of 0.78mg/ml against M. smegmatis was observed from the second harvest of field-cultivated seedlings of the control and Treatment 1 subgroups. The MIC values for shadehouse seedlings ranged from 1.6 to 6.3 mg/ml. Minimum bactericidal concentration (MBC) values from all the extracts tested were relatively higher than their respective MIC’s. Root extracts of E. natalensis were more active against M. tuberculosis and their MIC values were lower than the tested concentrations. Extracts acquired from field-grown seedlings were more active against M. smegmatis with a lowest MIC value of 0.78 mg/ml. Extracts from the control group and Treatment 1, which had less application of fertilizers were more active against strains of M. tuberculosis with MIC value of 10 µg/ml. This shows the selectivity of E. natalensis against the mycobacterial strain of M. tuberculosis. Based on the findings, synthesis and accumulation of naphthoquinones in E. natalensis is highly variable within individuals of the species investigated. Naphthoquinones accumulate in relatively higher amounts in roots of E. natalensis than in the aboveground structures, which validate their harvest by indigenous people. The concentration of shinanolone varied slightly and its production increased with seedling growth. The synthesis of 7-methyljuglone is independent of fertilisation as its accumulation was enhanced in seedlings subjected to control treatment. Neodiospyrin and isodiospyrin were always present in every sample obtained from the seedlings but they were not detectible in every profile of samples from mature plants. Diospyrin is the only naphthoquinone that was detected in every sample analysed and also quantified in high concentrations from mature plants harvested in spring. The study showed that depending on the requirement of a particular naphthoquinone for research, one could target the seasons and seedling stages recommended from this study. This study also showed that field-cultivated seedlings produced more potent naphthoquinones than the ones subjected to controlled environments. / Dissertation (MSc (Plant Science))--University of Pretoria, 2008. / Plant Production and Soil Science / unrestricted
63

Performance of elite cowpea (vigna unguiculata) genotypes at Mankweng and Bela-Bela, Limpopo Province

Sekgobela, Molebjane Marry January 2019 (has links)
Thesis (M. Sc. Agriculture (Agronomy)) -- University of Limpopo, 2019 / Cowpea (Vigna unguiculata) is a multi-purpose crop as it can be used for human consumption and livestock feeding. Cowpea serves as one of the cheapest sources of vegetable protein as the dry grain contains 25-30% protein. Its ability to tolerate drought and fix atmospheric nitrogen makes it suitable for marginal areas with low rainfall and poor soil fertility. However, low cowpea yields are common in Limpopo province due to shortage of improved varieties and lack of good seed for planting. The objectives of the present study were to determine growth, yield components and grain yield of elite cowpea genotypes across two locations and seasons, and to determine grain yield and yield components stability of the elite cowpea genotypes across the environments. The experiments were conducted at the University of Limpopo Experimental farm (Syferkuil) in Mankweng and Towoomba Research Station located in Bela-Bela, Limpopo Province during 2015/16 and 2016/17 growing seasons. The trials were carried out in a randomized complete block design (RCBD) consisting of three replications. Ten elite cowpea breeding lines (L1-L10) and a control check Bechuana White (BW) were planted at inter-row and intra-row spacings of 1 m and 0.3 m, respectively, in two rows of 6 m length. Round-up (isopropylamine salt of glyphosate) and Dual (S-metalachlor) at the rate of 3 L/ha and 0.5 L/ha, respectively, were used to control weeds at planting. Insecticide Karate (lambda-cyhalothrin) and Aphox (pirimicarb) at the rate of 1 L/ha and 500 g/ha were applied to control aphids, pod borers and other insects. Initial soil sampling was done at the depth of 0-20 cm to determine soil pH, organic matter, nitrate, ammonium, phosphorus and soil particle size. Agronomic data collected included number days to 50% flowering, number of days to 90% maturity, canopy width, plant height, peduncle length, number of pods per plant, pod length, hundred seed weight, fodder and grain yield. The collected data were subjected to analysis of variance using SAS software to determine the performance of the cowpea genotypes across the two locations and seasons. Means showing significant differences were separated using Duncan Multiple Range Test at the probability level of 5%. Data for number of days to 90% maturity, grain and fodder yields were further subjected to stability analysis through GGE biplot using Genstat software application. The results showed statistical differences for most of the studied traits as affected by genotype, location, seasonal effects and their interactions. Among the genotypes, average number of days to 50% flowering ranged from 53 to 60 days, while number of days to 90% maturity ranged from 89 to 96 days, with line L9 being the earliest to flower and mature. Tall plants were given by Line L5 (48.94 cm), followed by L7 (48.72 cm) and L10 (48.35 cm). Breeding line L7 recorded long peduncles with a mean of 36.37 cm. Number of pods per plant had a range of 16.00 to 25.52, while pod length varied from 14.46 to 17.63 cm, with line L7 having the highest number of pods per plant with long pods. Line L3 produced least number of pods per plant and shorter pods. Local check BW produced more number of seeds per pod as compared to all the breeding lines with a mean of 12.89 seeds/pod. One hundred seed weight varied from 15.67 g to 22.70 g among the genotypes. Grain yield among the genotypes ranged from 1441.20 to 2595.20 kg/ha with the best yielder being line L7, which was followed by line L2 (1928.00 kg/ha), L10 (1891.70 kg/ha) and Local variety BW (1858.70 kg/ha). The least grain yield was observed for line L8. Among the locations, Towoomba had significantly higher grain yield than Syferkuil with mean values of 1604.20 and 1982.20 kg/ha respectively. Significantly higher grain yield was recorded in 2016/17 season with a mean value of 1854.80 kg/ha than 2015/16 season (1732.30 kg/ha). Fodder yield ranged from 1934.20 to 3611.00 kg/ha, with line L3 being the highest yielder and it was followed by line L10 with an average of 3022.00 kg/ha. Local check BW produced the least fodder yields. The GGE biplot showed that lines L2, L9 and L4 matured earlier than all other lines including local variety BW and were stable across locations and seasons in terms of maturity. The biplot identified breeding lines L7, L2, L10 and Local check BW as the highest grain yielders but only line L7 and L2 were stable across the two locations and seasons. Lines L4, L10, L3, and L2 were the highest fodder yielders but only line L2 was stable across locations and seasons. Therefore, breeding lines L7 and L2 are recommended for both grain and fodder yield in both locations. Key words: cowpea, elite, breeding line, location, seasons, grain yield and stability.
64

Peromyscus Populations as Related to Seasons and Vefetative Types at the Hardware Ranch, Cache County, Utah

Turner, George Cleveland, Jr. 01 May 1950 (has links)
Members of the genus Peromyscus, White-footed Mice, are known to occur in nearly all habitats of North America. Because of their numerical abundance and widespread distribution, these mice are extensively used in the study of the dynamics of animal populations. Thus, information perteining to the local distruibution and activities of these mice is of value to the more comprehensive studies that are being carried out in the field of zoological research.
65

Kallbad vid Vinterviken / Cold bath at Vinterviken

Vitestam, Petter January 2018 (has links)
I vår snabba och upptagna värld med saker att göra, folk att träffa, platser att besöka, är det lätt att tappa kontakten med tidens gång, årstidernas förändring etc. Förändringar sker kring oss hela tiden men vi uppmärksammar dem ej, och rätt som det är har flera år flutit förbi. Vi brukade leva mer i synk med tiden och naturen, i ett naturligt förhållande till skiftningar och förändring, och jag tycker att det finns ett värde i att försöka återupprätta det förhållandet. Jag ville undersöka vårt förhållande till tid och närvaro och försöka hitta sätt som arkitektur kan hjälpa oss vara mer medvetna om vår plats i världen och tiden.Detta undersöks genom utformningen av ett kallbad som erbjuder besökaren en rituell resa av upplevelser. En plats där man kan slappna av och ha utrymme för eftertanke, ta sin tid att uppleva och se världen och sig själv på ett nytt sätt. Fokus ligger ej på eskapism och nöje utan på att skapa intensiva upplevelser som kan främja medveten närvaro. / In today's world we all live very fast, we all have places to be and stuff to do and most of the time we are not aware of time passing, seasons coming and going, changes happening etc. We used to live more closely connected with time and nature, and I think it is important to try to regain that connection. I wanted to look closer at our relationship to time and presentness, and try to find ways that architecture can help bring about an increased awareness of our place in the world.This is investigated through designing a cold bath which offers the user a ritual journey of experiences. A place where one can relax and reflect, and take ones time to experience and look at the world and one self in a new light. The focus is not on escapism or purely pleasure but rather on creating intense experiences to foster mindfulness.
66

Player Position Affects Relationship Between Internal and External Training Loads During Division I Collegiate Female Soccer Season

Ishida, Ai, Travis, S K., Draper, Garrison, White, Jason A., Stone, Michael H. 01 February 2022 (has links)
Ishida, A, Travis, SK, Draper, G, White, JB, and Stone, MH. Player position affects relationship between internal and external training loads during Division I collegiate female soccer season. J Strength Cond Res 36(2): 513-517, 2022-The purpose of this study was to investigate how competition phase and player position affect the relationship between internal and external training loads (ITL and ETL, respectively) in collegiate female soccer. Seventeen players participated (21.8 ± 1.7 years; 165.1 ± 6.2 cm; and 63.7 ± 7.9 kg). Nineteen match-plays (10 nonconference and 9 conference) were completed during the 2019 competitive season, including 270 observations of 17 players (defenders = 5, midfielders = 9, and forwards = 3). Internal training load was assessed using session rating of perceived exertion (sRPE). External training load included total distance and high-speed running (HSR) distance. A linear mixed model was compiled with fixed effects of total distance, HSR, competition phase, and player position (defenders, midfielders, and forwards) and random effects of player. There were statistically significant main effects for total distance (p < 0.001), HSR (p = 0.047) and player position (p = 0.045) on the prediction model of sRPE. However, the main effect of competition phase did not statistically contribute to the prediction model of sRPE (p = 0.38). In the final model, total distance (p < 0.001) and player position for forwards (p = 0.008) were significant predictors of sRPE. However, there was no statistically significant fixed effect of HSR on sRPE (p = 0.15). The final model explained 60.6% of the variance in sRPE (R2 = 0.60), whereas the random effect also explained 6.1% of the variance (R2 = 0.06). Our findings indicated that total distance and player position were strong predictors of sRPE. The relationship between ITL and ETL should be monitored by player position in female soccer players.
67

Students' with Visual Impairments Conceptions of Causes of Seasonal Change

Wild, Tiffany Ann 10 September 2008 (has links)
No description available.
68

Os professores de ci?ncias e suas pr?ticas: uma proposta did?tica para o ensino do conte?do esta??es do ano

Jesus, Daniel Marcos de 26 September 2016 (has links)
Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2017-04-03T21:49:05Z No. of bitstreams: 1 DANIEL disserta??o final.pdf: 4325548 bytes, checksum: b4560db31ae6473c5148330591094d47 (MD5) / Made available in DSpace on 2017-04-03T21:49:05Z (GMT). No. of bitstreams: 1 DANIEL disserta??o final.pdf: 4325548 bytes, checksum: b4560db31ae6473c5148330591094d47 (MD5) Previous issue date: 2016-09-26 / In this work, we analyze the understanding of Science, Geography and Education?s teachers of S?o Miguel das Matas, Bahia, about teaching and learning process of Seasons content that has been reflected on the construction and using of a didactic material (model System Earth-Sun), developed from a workshop with teachers who teach science?s classes in elementary school. The methodology has been based in questionnaires, videos and experimental demonstrations. The results showed that many science?s teachers have difficulties regarding to the understanding of the Seasons content. As a result, we can say that a didactic workshop in Seasons concept could make better the understanding of this content. / Neste trabalho, analisamos a compreens?o dos professores de Ci?ncias, Geografia e Pedagogia da cidade de S?o Miguel das Matas, Bahia, a respeito do processo de ensino e aprendizagem do conte?do de Esta??es do Ano e refletimos sobre a constru??o e utiliza??o de um material did?tico (maquete do Sistema Terra-Sol), desenvolvido a partir de uma Oficina com os professores que ministram aulas de Ci?ncias no Ensino Fundamental. Na metodologia foram utilizados question?rios, v?deos e demonstra??es experimentais. Os resultados demonstraram que muitos professores de ci?ncias apresentam dificuldades com rela??o ao entendimento do conte?do Esta??es do Ano e que ao trabalhar com materiais did?ticos dentro da Oficina Did?tica puderam compreender este conte?do.
69

Eficiência ambiental, divergência genética e composição química de grãos de soja no Estado do Tocantins

Daronch, Douglas José 07 April 2015 (has links)
A soja, uma das principais commodities do Brasil, tem o óleo e o farelo como matéria prima para a produção de alimentos e ração animal. Entretanto, são escassas as informações sobre os teores de óleo e proteína de grãos de cultivares nas diferentes épocas de plantio, sob condições de baixa latitude. Assim, o presente trabalho teve como objetivo avaliar a eficiência ambiental e a divergência genética de dezessete genótipos de soja, sendo dez cultivares comerciais e sete linhagens oriundas do Programa de Melhoramento Genético da UFT, em ensaios conduzidos no período de safra e entressafra, no ano agrícola 2013/14, em Palmas e Gurupi-TO. O delineamento experimental utilizado em cada ensaio foi de blocos casualizados, com dezessete tratamentos e três repetições. As características estudadas foram: florescimento, maturação, altura de planta, altura da inserção da primeira vagem, número de grãos por vagem, número de vagens por planta, massa de cem sementes, produtividade de grãos, teor de óleo e proteína, eficiência ambiental e divergência genética. A eficiência ambiental foi avaliada através da metodologia adaptada de Fischer (1983) e a divergência genética, por meio de procedimentos multivariados: distância generalizada de Mahalanobis e método de agrupamento e otimização de Tocher. As hibridações 5X6-3 e TMG 1180, 4X5-2 e TMG 1180; 5X6-1 e TMG 1180 são promissoras para obtenção de populações segregantes para produção de grãos. As características número de dias para o florescimento (49,%) e número de vagens por planta (26,6%) foram as que mais contribuíram para a dissimilaridade genética. Para a característica teor de óleo na safra, a maior eficiência foi alcançada pelo genótipo P98Y70, para entressafra o maior valor foi obtido por CD 2737 RR. Para a característica teor de proteína a maior eficiência no período de safra foi obtida pelo genótipo M 9144 RR, para entressafra foi M 8766RR. / Soy, one of the main commodities in Brazil, has oil and bran as raw material for the production of food and animal feed, respectively. However, information on the oil content and protein cultivars grains are scarce, in different planting dates under conditions of low latitude. Thus, this study aimed to evaluate the environmental efficiency and the genetic divergence of seventeen soybean genotypes, ten cultivars and seven lines in trials conducted during the crop season and off season in the agricultural year 2013/14, Palmas and Gurupi -TO. The experimental design used in each trial was a randomized block, with seventeen treatments and three replications. The characteristics studied were flowering, maturity, plant height, pod height, number of seeds per pod, number of pods per plant, weight of hundred seeds, grain yield, oil content, protein, environmental efficiency and the genetic divergence. Environmental efficiency was evaluated using the methodology adapted from Fischer (1983) and the genetic divergence through multivariate procedures: generalized Mahalanobis and grouping method and Tocher. The 5X6-3 hybridizations and TMG 1180, 4X5-2 and TMG 1180; 5X6-1 and TMG 1180 are promising for obtaining segregating populations for grain production. Features number of days to flowering (49%) and number of pods per plant (26.6%) were the ones that contributed most to the genetic dissimilarity. For the characteristic oil content in the harvest, the highest efficiency was achieved by P98Y70 genotype for off season the highest value was obtained by CD 2737 RR. For the characteristic protein content greater efficiency in the harvest period was obtained by the M 9144 RR genotype for off season was M 8766RR.
70

N?veis de ?cidos graxos e qualidade de ovos comerciais convencionais e enriquecidos com ?mega-3. / Fatty acid levels and quality of conventional and enriched omega-3 eggs.

Cedro, Thaiz Marinho Magalh?es 29 August 2008 (has links)
Made available in DSpace on 2016-04-28T14:59:48Z (GMT). No. of bitstreams: 1 2008 - Thaiz Marinho Magalhaes Cedro.pdf: 1901514 bytes, checksum: e3897dc76edd8a3714a6678cf8139f8f (MD5) Previous issue date: 2008-08-29 / 1160 eggs were utilized in four experiments were conducted in Eggs Analyses Laboratory of the Institute of Animal Science of the Rural Federal University of Rio de Janeiro (UFRRJ) using commercial eggs produced by two groups of laying hens line Isa Brown with 33 weekold. In group 1, the birds were fed throughout their productive life with a basic diet of corn and soybean meal, while in group 2, since 22? weeks-old of the hens, was added to the basic diet 1.5% of marine algae substrate and 1.8% fish oil (production of enriched &#969;-3 eggs). In experiment 1, whose aim was to evaluate the internal and external quality of conventional and enriched &#969;-3 eggs stored at different temperatures, it was found that both types of eggs studied had similar characteristics of internal and external quality. Eggs stored for 21 days at 25?C had lower averages for Haugh unit and yolk index and higher averages of albumen pH and yolk pH when compared to other treatments related to temperature and period of storage. There were no significant differences in egg shell thickness, shell weight and shell percentage between the two types of eggs stored for 21 days, regardless of the temperature of storage. In experiment 2 was assessed the influence of the season on the quality of enriched &#969;-3 eggs stored in refrigerated environment. In this second issue was verify that the eggs collected in the summer showed eggs weight and internal and external quality aspects lower than those collected in winter. In this second issue was verify that the eggs collected in the summer showed eggs weight and internal and external quality aspects lower than those collected in winter. In this second issue was verify that the eggs collected in the summer showed eggs weight and internal and external quality aspects lower than those collected in winter. The storage affected negatively the eggs weight, Haugh unit and yolk index, but there was no effect on the shell thickness. In experiment 3 was compared the fatty acids levels and relationships in conventional and enriched &#969;-3 eggs. The enriched &#969;-3 eggs showed total levels of &#969;-3 polyunsaturated (1839 mg/100g of yolk) and monounsaturated fatty acids (10,744 mg/100g of yolk) higher than those of conventional eggs (927 and 7997 mg/100g of yolk, respectively). Relations between polyunsaturated/saturated fatty acids (P/S) and between &#969;-6/&#969;-3 of enriched eggs were close to the ideal estimated for human consumption (1.10 and 3.00, respectively). The conventional eggs had total levels of saturated (8740 mg/100g of yolk) and &#969;-6 polyunsaturated fatty acids (9600 mg/100g of yolk) significantly higher than the enriched &#969;-3 eggs (6640 and 5510 mg/100g of yolk, respectively). In Experiment 4, three people individually assessed the intensity of yolk pigmentation with a color range. It was found that conventional eggs had the yolk less pigmented enriched &#969;-3 ones. The storage at different temperatures caused the appearance of dark spots in the egg yolks enriched. Based on the results obtained in experimental conditions used it was found that enriched &#969;-3 eggs showed high levels of &#969;-3 polyunsaturated fatty acids, appropriate balance of the relations between P/S and between &#969;-6/&#969;-3 and good characteristics of internal and external quality, thus those eggs can be considered an excellent alternative food for those consumers concerned about eating healthy diets. / Foram utilizados 1160 ovos comerciais em quatro experimentos realizados no Laborat?rio de An?lises de Ovos do Instituto de Zootecnia da Universidade Federal Rural do Rio de Janeiro (UFRRJ) produzidos por dois grupos de poedeiras da linhagem Isa Brown com 33 semanas de idade. No grupo 1, as aves foram alimentadas durante toda vida produtiva com ra??o a base de milho e farelo de soja (produ??o de ovos convencionais), enquanto que no grupo 2, ? partir da 22? semana de idade das aves, foi acrescentado a ra??o b?sica 1,5% de substrato de algas marinhas e 1,8% de ?leo de peixe (produ??o de ovos enriquecidos com &#969;-3). No experimento 1, cujo objetivo foi avaliar a qualidade interna e externa de ovos comerciais convencionais e enriquecidos com &#969;-3 armazenados em diferentes temperaturas, foi verificado que os dois tipos de ovos estudados apresentaram caracter?sticas de qualidade interna e externa semelhantes. Os ovos armazenados por vinte e um dias a 25?C apresentaram menores m?dias para unidade Haugh e ?ndice de gema e maiores para pH do alb?men e da gema quando comparado aos demais tratamentos relacionados a temperatura e per?odo de armazenamento. N?o foram observadas diferen?as significativas para espessura, percentual e peso da casca entre os dois tipos de ovos estocados por vinte e um dias, independentemente da temperatura de armazenamento. No experimento 2 foi avaliada a influ?ncia da esta??o do ano sobre a qualidade de ovos enriquecidos com &#969;-3 armazenados em ambiente refrigerado. Neste segundo ensaio foi observado que os ovos coletados no ver?o apresentaram peso, qualidade interna e externa inferior ao daqueles coletados no inverno. Com rela??o ao armazenamento, foi verificado efeito negativo sobre o peso, unidade Haugh e ?ndice de gema, mas n?o houve efeito sobre a espessura da casca destes ovos. No experimento 3, comparou-se os n?veis de ?cidos graxos e suas rela??es em ovos comerciais convencionais e enriquecidos com &#969;-3 e foi verificado que os ovos enriquecidos com &#969;-3 apresentaram teores totais de ?cidos graxos (AG) poliinsaturados da s?rie &#969;-3 (1839 mg/100g de gema) e de AG monoinsaturados (10744 mg/100g de gema) significativamente superiores aos dos ovos convencionais (927 e 7997 mg/100g de gema, respectivamente). As rela??es entre os ?cidos graxos poliinsaturados/saturados (P/S) e entre &#969;-6/&#969;-3 dos ovos enriquecidos foram pr?ximas ao ideal estimado para o consumo humano (1,10 e 3,00; respectivamente). Os ovos convencionais apresentaram teores totais de AG saturados (8740 mg/100g de gema) e de AG poliinsaturados da s?rie &#969;-6 (9600 mg/100g de gema) significativamente superiores aos dos ovos enriquecidos &#969;-3 (6640 e 5510 mg/100g de gema, respectivamente). No experimento 4, tr?s pessoas individualmente avaliaram a intensidade de pigmenta??o da gema com o aux?lio de um leque colorim?trico. Foi verificado que os ovos convencionais apresentaram gema menos pigmentada que os ovos enriquecidos com &#969;-3. O armazenamento em diferentes temperaturas provocou o aparecimento de manchas escuras nas gemas dos ovos enriquecidos. Com base nos resultados obtidos nas condi??es experimentais utilizadas concluiu-se que os ovos enriquecidos com &#969;-3 apresentaram elevados n?veis de AG poliinsaturados da s?rie &#969;-3, balan?o adequado das rela??es entre &#969;-6/&#969;-3 e P/S e boas caracter?sticas de qualidade interna e externa, sendo desta forma, considerados uma excelente alternativa de alimento para aqueles consumidores preocupados em ingerir dietas mais saud?veis.

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