The study includes separate papers, which are all linked by their emphasis on the effect of different diets on the impact of the development of the small intestine of the young ostrich. This abstract is intended to provide readers with a broad overview of the outcomes of the study. Part 1: Yolk utilisation and the development of the small intestines Chapter 2 deals with the composition of egg yolk as it is absorbed by starved ostrich Struthio camelus L. ) chicks from one to seven days post-hatching and for ostrich (Struthio camelus L.) chicks from one to sixteen days post-hatching on a pre-starter broiler diet. Chapter 3 provides information on the intestinal enzymes of ostrich (Struthio camelus L. ) chicks from one to sixteen days post-hatching on a pre-starter broiler diet. The effect of growth on enzyme activity immediately post-hatching up to sixteen days of age was studied. Chapter 4 details a histological and morphological study of the gastrointestinal tract of ostrich (Struthio camelus L.) chicks from two to sixteen days post-hatching on a pre-starter broiler diet. The effect of growth on histological and morphological changes in the various parts of the small intestines was examined. Part 2: Influence on various pre-starter diets on growth and the development of the intestinal tract Chapter 5 discussed a growth and digestibility study of ostrich (Struthio camelus L.) chicks on eight different pre-starter diets. The performance, growth and physiological development of the chicks on high and low variations of different nutritional components were examined. Chapter 6 provides information on certain intestinal enzymes of ostrich (Struthio camelus L.) chicks on the eight different pre-starter diets. Chapter 7 dealt with the histological and morphological changes of the gastrointestinal tract of ostrich (Struthio camelus L.) chicks as a result of high and low variations of different nutritional components in prestarter diets. Implications The first part of this study revealed that although it appeared that yolk content was absorbed faster in starved ostrich chicks, intake of external feed had a positive influence on the absorption of fat from the yolk. The changes in the fatty acid composition of the yolk fat content that were observed may indicate that ostrich chicks have the ability to withdraw certain fatty acid components, especially unsaturated fatty acids. The digestive tract of ostrich chicks was compared with that of broiler chicks and differences observed in amylase and lipase activity between the birds in this trial and in poultry could be due to genetic differences between species. It could also be due to the genetic homogeneity of the poultry chicks that were used in the trials, whereas ostrich chicks have not been subjected to the same extent of advanced breeding improvement to date. Results on histological and morphological growth of the small intestines of the ostrich chick indicate increased absorption with an increase in age. The second part of this study revealed that ostrich chicks performed differently on diets formulated with different nutritional components. It appears that a high fat and low sugar content in the diet is advantageous in ostrich pre-starter diets. Although there were a few mortalities during the trials, there is no clear indication as to why the chicks died, as the causes of mortalities were not investigated. Differences in composition of the eight pre-starter diets did not seem to have an influence on the protein content or enzyme activity of the small intestines of ostrich chicks. An anti-nutritional factor within certain feedstuffs may, however, have had an influence on enzyme activity. Similar results were obtained for the histological and morphological parameters which were measured in chicks fed the different diets. There was no single diet that promoted intestine development, although it seemed as if the small intestines of the chicks fed the high protein diet were under higher digestive stress than those of the chicks fed the other diets. / Thesis (PhD)--University of Pretoria, 2011. / Anatomy and Physiology / Unrestricted

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No. of bitstreams: 1 oliveira_krb_me_jabo.pdf: 2302462 bytes, checksum: 2cef5c4c9d0cc1b9d04d7b59e343a79c (MD5) Previous issue date: 2016-07-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Devido ao maior interesse por biocombustíveis, indústrias brasileiras iniciaram, recentemente, a produção de etanol também a partir de grãos de milho, gerando um resíduo com potencial de uso como ingrediente em rações para animais, o DDGS (grãos secos de destilaria com solúveis). Por resultar de processos de fermentação de grãos de milho por leveduras e enzimas, este resíduo possui um elevado teor proteico e baixo teor de carboidratos solúveis, o que o torna boa fonte de proteína vegetal em rações para animais. Além do baixo custo, possíveis benefícios relacionados aos resíduos de leveduras e enzimas restantes da fermentação também contribuem para seu potencial de mercado. Desta forma, com este trabalho, objetivou-se avaliar a viabilidade de inclusão do DDGS do milho em dietas para juvenis de Piaractus mesopotamicus em substituição ao farelo de soja. Para tal, foram realizados três ensaios experimentais. No primeiro ensaio avaliaram-se os coeficientes de digestibilidade aparente (CDA) de nutrientes do DDGS para juvenis de P. mesopotamicus (13±0.3 gramas), distribuídos, em delineamento inteiramente casualizado (DIC), em seis tanques de fibra de vidro, na densidade de 35 peixes tanque -1 em sistema de recirculação contínuo de água. A coleta das fezes foi realizada em sistema de Guelph modificado. Após obtenção dos CDAs, foram formuladas dietas contendo cinco diferentes níveis de inclusão de DDGS (0, 10, 20, 30 e 40%) utilizadas nos ensaios posteriores. O segundo ensaio consistiu na avaliação dos CDAs dos nutrientes das dietas contendo 0, 10, 20, 30 e 40% DDGS, onde juvenis de P. mesopotamicus (27±1.4 gramas) foram distribuídos em cinco tanques de fibra de vidro na densidade de 30 peixes tanque -1 em sistema de recirculação de água. Utilizou-se delineamento em Quadrado Latino, 5x5 (05 dietas e 05 períodos). Concomitantemente ao segundo ensaio, e sob o mesmo sistema de recirculação, juvenis de P. mesopotamicus (21±0.2 gramas) foram distribuídos em 20 tanques de fibra de vidro, na densidade de 15 peixes tanque -1, em DIC, e alimentados com as dietas por 100 dias. Neste terceiro ensaio foram avaliados parâmetros de desempenho produtivo, viabilidade econômica, atividade das enzimas digestivas e de estresse oxidativo do intestino, bem como morfologia intestinal dos juvenis. Os dados obtidos de desempenho produtivo, estresse oxidativo e morfometria intestinal foram submetidos à one-way ANOVA e em caso de significância (p < 0.05) foi realizado teste de Tukey adotandose 5% como nível de probabilidade. Dados de enzimas digestivas foram submetidos a two-way ANOVA e em caso de significância para interação foi feita uma one-way ANOVA e teste Tukey a 5%. Os valores obtidos para os CDA do DDGS confirmaram seu potencial de uso como ingrediente proteico em dietas para P. mesopotamicus, assim como os resultados de desempenho produtivo, onde se obteve menor valor de conversão alimentar e melhor eficiência de retenção de proteína para a dieta contendo maior nível de inclusão de DDGS (40DDGS). Os demais parâmetros de desempenho não foram afetados significativamente. A atividade das enzimas digestivas foi reduzida da porção anterior do intestino para distal e para as dietas com níveis superiores a 10% de DDGS. A inclusão de DDGS levou a redução do status oxidativo do intestino e melhoras na morfometria intestinal. Sendo assim, é possível o uso de até 40% de DDGS do milho como ingrediente proteico em dietas para juvenis de P. mesopotamicus, substituindo em totalidade o farelo de soja, mantendo os valores de desempenho produtivo, melhorando a saúde intestinal dos peixes bem como a capacidade de absorção e aproveitamento dos nutrientes disponibilizados na dieta. / Due to the increased interest in biofuels, Brazilian companies started recently, the production of ethanol from corn, generating a waste with potential for use as an ingredient in animal feed, the DDGS (dried distillers grain with soluble). As its processes results from fermentation of corn grain by yeast and enzymes, this residue has high protein and low soluble carbohydrates, which makes it good source of vegetable protein for animal feed. Besides the low cost, possible benefits related to yeast residues and other enzymes from fermentation may also contribute to DDGS market potential. Thus, this work aimed to evaluate the feasibility of inclusion of corn DDGS in diets for Piaractus mesopotamicus juveniles to replace soybean meal. To this end, there were three experimental runs. In the first assay we evaluated the apparent digestibility coefficients (ADC) of DDGS nutrients for P. mesopotamicus (13 ± 0.3 grams), distributed in a completely randomized design (CRD) in six fiberglass tanks, at density of 35 fish tank-1 in a continuous recirculating water system. The collection of feces was carried out in modified Guelph system. After obtaining the ADCs, diets were formulated with five different levels of DDGS inclusion (0, 10, 20, 30 and 40%) used in subsequent assays. The second test was the evaluation of ADCs of nutrient in the diets containing 0, 10, 20, 30 and 40% DDGS where P. mesopotamicus juvenile (27 ± 1.4 g) were distributed in five fiberglass tanks at density of 30 fish tank-1 in a recirculating water system. We used a Square Latino design, 5x5 (05 diets and 05 periods). Concomitantly to the second test, and under the same recirculation system, P. mesopotamicus juveniles (21 ± 0.2 grams) were divided into 20 fiberglass tanks, at density of 15 fish tank-1 in CRD, and fed diets for 100 days. In this third test were evaluated growth performance, economic viability, activity of digestive enzymes and oxidative stress of the intestine and intestinal morphology of juveniles. Data obtained for growth performance, oxidative stress and intestine morphology were subjected to one-way ANOVA and in case of significance (p <0.05) Tukey's test was carried out adopting a 5% probability level. Data from digestive enzymes were subjected to two-way ANOVA and in case of significance to interaction was made a one-way ANOVA and Tukey's test at 5%. The ADCs values obtained for the DDGS confirmed its potential use as a protein ingredient in diets for P. mesopotamicus, as well as the results of productive performance, which showed lower value of feed conversion ratio and an improved on protein retention efficiency for the diet containing higher inclusion level of DDGS (40DDGS). The other performance parameters were not significantly affected. The activity of the digestive enzymes was reduced from anterior to distal portion of the intestine and for diets with levels above 10% DDGS. The DDGS inclusion led to reduction of oxidative status of the intestine and improvement in intestinal morphology. Thus, the use of up to 40% corn DDGS as a protein ingredient for P. mesopotamicus juvenile is possible, replacing in whole soybean meal, keeping the growth performance, improving fish gut health as well as the absorption and utilization of nutrients available in the diet. / CNPq: 130664/2014-6 / FAPESP: 2014/16685-5 / FAPESP: 2015/21245-7