O estudo consistiu em quatro experimentos com o objetivo de avaliar a redução proteica e níveis de metionina+cistina sobre o desempenho e qualidade de ovos (produção de ovos, consumo de ração, conversão alimentar, peso de ovo e fatores de qualidade dos ovos, unidade Haugh, espessura de casca, resistência à quebra, pigmentação de gema, gravidade específica) de poedeiras comerciais leves e semipesadas de 24 a 40 semanas de idade. Em cada experimento, foram utilizadas 240 poedeiras comerciais distribuídas em delineamento inteiramente casualisado com 8 aves por unidade experimental com 10 repetições. Os níveis dos aminoácidos, treonina, triptofano e valina foram mantidos os mesmos em todos os tratamentos através da suplementação de aminoácidos sintéticos. No primeiro e segundo experimentos avaliaram-se três níveis de proteína bruta (15,4%, 16,4% e 17,4%) em dietas para aves leves (experimento I) e aves semipesadas (experimento II) das linhagens Bovans White e Bovans Brown, respectivamente. No experimento I não foram observadas diferenças estatísticas para os parâmetros relacionados à qualidade da casca do ovo, nem mesmo para altura de albúmen e peso do ovo. A redução do nível proteico da dieta para 16,4% não afetou o desempenho das poedeiras leves (P<0,05). No experimento II, não houve diferenças estatísticas para os parâmetros avaliados. Nos experimentos III e IV avaliou-se o efeito de dois níveis de proteína bruta (16,4% e 17,4%) e dois níveis metionina+cistina (0,66% e 0,77) em dietas para aves leves (experimento III) e aves semipesadas (experimento IV) das linhagens Bovans White e Bovans Brown. No experimento III a qualidade de ovo não foi influenciada pelos tratamentos. Houve interação entre os níveis de proteína bruta e aminoácidos sulfurados para as variáveis de produção de ovos, consumo de ração e conversão alimentar por dúzia de ovos. As aves alimentadas com a dieta com 15,4% de proteína bruta apresentaram menor produção de ovos quando comparado às aves que receberam dietas com níveis de AAST elevados e com PB elevada. As aves alimentadas com 17,4% de PB e 0,77% de aminoácidos sulfurados apresentaram maior consumo e pior conversão alimentar (P<0,05). O aumento no nível de AAST resultou em maior peso do ovo. No experimento IV houve interação entre os fatores estudados, sendo que as aves alimentadas com níveis mais baixos de PB e AAST (16,4% e 0,66%, respectivamente), apresentaram menor produção de ovos e pior conversão alimentar. Para a variável peso de ovos, houve efeito dos níveis de AAST, sendo que as aves alimentadas com 0.77% produziram ovos com maior peso (P<0,05). / The study consisted of four experiments to evaluate the effect of protein and reduced levels of methionine+cystine on the performance and egg quality (egg production, feed intake, feed conversion, egg weight and egg quality factors, Haugh unit, shell thickness, breaking strength, yolk pigmentation) of light and semi heavy weight laying hens with 24-40 weeks of age. In each experiment 240 laying hens were distributed in a completely randomized design with 8 birds per experimental unit with 10 replicates. Levels of, threonine, tryptophan and valine were kept the same in all treatments by supplementation of synthetic aminoacid. In experiments I and II were evaluated three levels of crude protein (15.4%, 16.4% and 17.4 %) on diets for light Bovans White hens (experiment I) and Bovans Brown semi heavy weight (experiment II). In the first experiment there was no statistical differences in the parameters related to the quality of the egg shell, even for albumen height and egg weight were observed. The reduction of the protein level of the diet to 16.4% did not affect the performance of laying hens (P<0.05). In experiment II there were no statistical differences in the parameters evaluated. In experiments III and IV evaluated the effect of two levels of crude protein (16.4% and 17.4%) and two methionine + cystine levels (0.66% and 0.77%) on diets for light Bovans White hens (experiment III) and Bovans Brown semi heavy weight (experiment IV). In experiment III the egg quality was not affected by treatments. There was interaction between the levels of crude protein and sulfur aminoacids for the variables of egg production, feed intake and feed conversion per dozen eggs. Hens fed diets with lower protein levels had lower egg production when compared to hens fed diets with high levels of TSAA and high CP. Hens fed with diets with 17.4% of CP and 0.77% of sulfur aminoacids had higher intake and worse feed conversion (P<0.05). The increase in the level of TSAA resulted in higher egg weight. In experiment IV there was interaction between the factors studied, where lower levels of CP and TSAA (16.4% and 0.66 %, respectively), had lower egg production and lower feed conversion. For egg weight, there was effect of TSAA. Hens fed diets with 0.77% of TSAA produced heavier eggs (P<0.05).

Orientador: Edivaldo Antonio Garcia / Banca: Lúcio Francelino Araújo / Banca: Ricardo de Albuquerque / Resumo: Com o objetivo de comparar níveis de cálcio e fósforo durante toda a fase de produção, foi realizado um experimento utilizando-se 720 codornas japonesas (Coturnix coturnix japonica) com 7 semanas de idade. O período experimental teve duração de 48 semanas e utilizou-se quatro níveis de cálcio (2,0; 2,5; 3,0 e 3,5%) e três níveis de fósforo (0,25; 0,35 e 0,45%) divididos em 12 tratamentos com 6 repetições cada. O experimento foi dividido em 3 fases: período inicial de produção (4 primeiros ciclos de 28 dias: 7 a 22 semanas de idade), período intermediário (4 ciclos de 28 dias: 23 a 38 semanas de idade) e período final de produção (os últimos 4 ciclos de 28 dias: 39 a 54 semanas de idade). O desempenho das aves e a qualidade dos ovos foram avaliados ao final de cada ciclo de 28 dias, e teores de cálcio e fósforo presentes no plasma, ao final do período experimental (54 semanas de idade). Concluiu-se que independente da fase de produção, as exigências nutricionais de cálcio e fósforo para codornas japonesas em postura que proporcionam bom desempenho produtivo e manutenção satisfatória da qualidade dos ovos são de 2,5% e 0,25%, respectivamente / Abstract: With the objective to compare levels of calcium and phosphorus during all the production phase, was conducted an experiment using 720 Japanese quails (Coturnix coturnix japonica) with 7 weeks of age. The experimental period lasted 48 weeks, and used four levels of calcium (2.0; 2.5; 3.0 e 3.5%) and three levels of phosphorus (0.25; 0.35 e 0.45%) divided into 12 treatments with six replicates. The experiment was divided into three phases: initial production phase (the first 4 cycles of 28 days: 7 to 22 weeks), intermediate phase (4 cycles of 28 days: 23 to 38 weeks) and the final production phase (the last 4 cycles of 28 days: 39 to 54 weeks). The bird performance and egg quality were evaluated after each cycle of 28 days, and grades of calcium and phosphorus in the plasma, at the end the experimental period (54 weeks). It was concluded that regardless of production phase, the nutritional requirements of calcium and phosphorus to Japanese cleaned common quails in posture that provide good performance productive and satisfactory maintenance of the quality of eggs are 2.5% and 0.25% respectively / Mestre

Thesis (M.Sc. (Animal production)) --University of Limpopo, 2011 / A study was conducted to examine the effect of protein level of the diet of Naked neck hens on egg production, hatchability and chick productivity. The first part of the experiment determined the effect of protein level on feed intake, number of eggs produced, egg weight, egg white nitrogen content, egg yolk nitrogen content, egg hatchability and chick hatch-weight. A total of 25 hens aged 30 weeks were confined in cages and fed diets differing in protein content. A complete randomized design, comprising of diets differing in protein levels (P12.94%, P13.94%, P14.38%, P15.75% and P18.13% CP), replicated five times with one hen in each replicate was used. Semen was collected from one cock to fertilize all hens. Protein level had an effect on (P<0.05) feed intake and egg white nitrogen content. However, protein level of the diet of hens had no effect(P>0.05) on the number of eggs produced, egg white nitrogen content, egg yolk,egg weight, egg hatchability and chick hatch-weight. Quadratic analyses indicated that feed intake, number of eggs produced, egg weight, egg white nitrogen content, egg yolk nitrogen content, hatchability and chick hatch-weight were optimized at different protein levels of 14.7 (r2 = 0. 623),14.9 (r2 = 0.568),13.9 (r2 = 0.094), 18.2 (r2 = 0.563), 15.1(r2 = 0.424), 15.9 (r2 = 0.451) and 15.9 %(r2 = 0.898) , respectively. The second part of the experiment determined the effect of protein level of hens on productivity of their progenies from a day old up to 13 weeks of age. A total of 95 chicks hatched from the first part of the study were assigned to 20 floor pens according to the number of chicks hatched. Chicks had an average initial live weight of 35 ± 2 g per bird. The chicks were fed the same commercial grower diet and fresh water ad libitum up to seven weeks of age. Protein level of the diet of Naked neck hens had an effect (P<0.05) on feed intake, live weight and feed conversion ratio of chicks from a day old up to seven weeks of age. However, protein level of the diet of Naked neck hens had no effect (P>0.05) on growth rate and mortality of chickens from a day old to seven weeks of age. Feed intake, feed conversion ratio, growth rate and mortality of chickens were optimized atdifferent protein levels of 15.8 (r2 = 0.298), 16.1 (r2 = 0.236), 16.1 (r2 = 0.077) and 14.3 % (r2 = 0.617), respectively. Protein level of the diet of Naked neck hens had no effect (P>0.05) on feed intake, growth rate and feed conversion ratio of both their male and female progenies between eight and 13 weeks of age. Protein levels of the diet of hens had an effect (P<0.05) live weight of their male progenies and carcass weights of both their male and female progenies at 13 weeks of age. However, the level of protein of the diet of hens had no effect (P>0.05) on live weight of their male progenies, and breast meat yield, breast meat nitrogen content and fat pad weight of both their male and female progenies at 13 weeks of age. Live weight,breast meat yield, breast meat nitrogen content and fat pad weight of their male progenies at 13 weeks of age were optimized at different protein levels of the diets of hens of 18.9 (r2 = 0.666), 15.6 (r2 = 0.081), 15.4 (r2 = 0.786) and 17.7 %(r2 = 0.775), respectively. Similarly, live weight, carcass weight, breast meat yield, breast meat nitrogen content and fat pad weight of their female progenies at 13 weeks of age were optimized at different protein levels of 15.7 (r2 = 0.294),15.4 (r2 = 0.180), 15.8 (r2 = 0.059), 15.1 (r2 = 0.882) and 16.1 % (r2 = 0.405), respectively. It is concluded that protein level of the diet of the hen may affect its productivity and that of its progeny. However, the calculated protein levels for optimum productivity will depend on the production parameter in question. / National Research Foundation

Thesis (MA.Agricultural Management (Animal Production)) -- University of Limpopo, 2013 / The objectives of the study were to evaluate the productivity of the Vhembe egg production project and determine the management and socio-economic factors affecting productivity. The data were collected from 2005 to 2007. Thirty-two farmers from four municipalities were randomly selected. Each household received a once-off unit consisting of a cage with eighteen point of lay chickens 4x50 bags of laying mesh, feeding and drinking troughs. Production records from sampled farmers were used in the analysis. Data included monthly egg production, eggs consumed, eggs sold, income from eggs, production costs, monthly feed utilization and mortality. Primary data on educational standards, socio-economic characteristics (age and gender of the household head, farming size, level of education and alternative income, were collected using a questionnaire. The study revealed that sex, age and educational level had impact on production as low production was associated with older farmers and low level of education. These factors should be considered when planning community projects. Chicken rearing and ownership is often shared among the family members, in this study, the management was predominantly by women (63%) and children (18%). This may be an indication that if assistance efforts are targeted towards women, village poverty could be significantly reduced. It is concluded that the low income accrued from the project explains the reason for high abandonment or neglect of the project. The income received from the project is smaller than the government grants and as such not attractive. It is not surprising that presently most farmers have abandoned the project. It is noted that if labour costs had been taken into consideration, the project would be running at a serious loss and the resultant output would discourage even the most enthusiastic farmers.

Thesis (M.A. Agricultural Management (Animal Production)) -- University of Limpopo, 2013 / The objectives of the study were to evaluate the productivity of the Vhembe egg production project and determine the management and socio-economic factors affecting productivity. The data were collected from 2005 to 2007. Thirty-two farmers from four municipalities were randomly selected. Each household received a once-off unit consisting of a cage with eighteen point of lay chickens 4x50 bags of laying mesh, feeding and drinking troughs. Production records from sampled farmers were used in the analysis. Data included monthly egg production, eggs consumed, eggs sold, income from eggs, production costs, monthly feed utilization and mortality. Primary data on educational standards, socio-economic characteristics (age and gender of the household head, farming size, level of education and alternative income, were collected using a questionnaire. The study revealed that sex, age and educational level had impact on production as low production was associated with older farmers and low level of education. These factors should be considered when planning community projects. Chicken rearing and ownership is often shared among the family members, in this study, the management was predominantly by women (63%) and children (18%). This may be an indication that if assistance efforts are targeted towards women, village poverty could be significantly reduced. It is concluded that the low income accrued from the project explains the reason for high abandonment or neglect of the project. The income received from the project is smaller than the government grants and as such not attractive. It is not surprising that presently most farmers have abandoned the project. It is noted that if labour costs had been taken into consideration, the project would be running at a serious loss and the resultant output would discourage even the most enthusiastic farmers.

The main aim of this thesis was to study domestication effects on foraging behaviour in chickens and to investigate whether and how domestication and selection for high production have influenced adaptability in chickens. Two domestic strains of chickens (egg layers and meat type chickens) and their wild ancestor, the red jungle fowl (RJF) were compared in different test situations with respect to foraging behaviour and adaptability. The domestic strains showed a modified foraging strategy, where they were less inclined to explore and feed from a hidden food source, i.e. they showed less contrafreeloading (CFL, the behaviour of working for food even though identical food can be easily obtained) than RJF. The difference in CFL between RJF and the layers were not altered by food deprivation, which suggests that the lower CFL in the layers represents a genetically based difference in feeding strategy. In addition, CFL decreased with age in RJF and layers and social isolation decreased CFL in RJF. Furthermore, when foraging, RJF acquired information about the quality of different food sources, which was utilised after a change in environmental conditions. Contrary to this, layers gained less information during foraging and showed an impaired spatial learning ability compared to RJF, and in this respect, layers showed a lower degree of adaptability. Chronic stress impaired the learning capacity of both breeds but RJF seemed to be overall faster to learn to locate food in a spatial learning task. Furthermore, stressed RJF started to eat faster in the spatial learning test than non-stressed RJF, and contrary to this, stressed layers showed a more passive response by prolonging the time to start feeding compared to non-stressed layers. This indicates a more active response to stress in RJF than in layers. Similarly, when RJF and layers were exposed to food deprivation, RJF showed an active response by increasing their time spent on foraging behaviour. The general results in this thesis most likely reflect different adaptive strategies, where RJF appear to be better adapted to a stochastic environment, and the domestic strains to grow and produce egg in a more predictable environment. The findings are in accordance with the resource allocation theory, which suggests that animals selected for high production are expected to reallocate a high proportion of resources into production traits and hence fewer resources might be left to other biological processes, e.g. exploratory behaviour. Selection for high production seems to influence the ability of chickens to cope with a changing environment, which may have implications for the welfare of chickens in a production environment.

Production, egg quality, behaviour, and physical condition were compared from Wk 20 to Wk 50 among three beak- trimmed commercial laying strains, Lohmann White (LW), H & N White (HN), Lohmann Brown (LB), and a non-commercial Cross between Rhode Island Red (male) and Barred Plymouth Rock (female) in conventional cages and in floor pens. All chicks were reared in their respective environments, and 450 and 432 pullets were housed at 18 and 7 weeks of age in cages and floor pens respectively. Hens in cages were provided with 688 cm2/bird and those in pens with over 6,000 cm2/bird, both of which are more than provided by commercial standards. Body weights and eggshell weights were higher for birds in floor pens than those in cages, and although they increased with age, body weight of hens in cages decreased at Wk 50. White-egg layers (LW, HN) used perches and nest boxes more than Brown-egg layers (LB, Cross). During the laying period, mortality was higher for all strains in cages and during the rearing period mortality was higher in floor pens for LB hens but not other strains. No aggressive behaviours were found, but the frequency of gentle feather pecking and pecking at the enclosure was higher in cages than in floor pens. Feather condition deteriorated over time in cages mainly because of contact with the cage wires whereas in floor pens, feather condition of birds at Wk 20 was not different from that at Wk 50. The frequency of keel bone deformities was higher for White-egg layers than for Brown-egg layers in cages and was higher for Cross hens than other strains in floor pens. Claws were longer in cages than in the floor pens. Foot condition was worse in floor pens than in cages. The welfare indicators used in this study showed that cages restricted the hens' behaviour compared to floor pens and resulted in higher laying period mortality, reduced body weight and deteriorated feather condition than floor pens. Both systems had advantages and disadvantages in regard to the hens’ health and welfare. The use of environmental complexities was strain specific in floor pens. The environment by genotype interactions suggests that the strain should be considered when considering alternative housing systems.

Metal mines release treated effluents that contain a variety of metals, metalloids, and organics into the aquatic environment. A number of metal mine effluents (MMEs) have been found to contribute to adverse effects in fish and benthic invertebrates, such as decreased diversity and density, however the specific causal factors of toxic responses during chronic exposures to the MMEs are often unknown. Therefore, the overall objective of this dissertation was to explore causative and modifying factors of MME toxicity to a resident fish species, the fathead minnow (Pimephales promelas), during chronic, multi-trophic exposures. The representative MME used in this study was the process water effluent (PWE) of a Canadian metal mine, which is released into Junction Creek in Sudbury, Ontario, Canada. Chronic exposure to the MME has been a source of decreased reproductive output in fathead minnows in several previous studies, however, these same studies were not able to determine the potential causal factors of the reproductive impairment. In order to address the overall objective, several laboratory mesocosm studies were conducted, which consisted of three separate components. The first component included exploring several metals (Cu, Ni, and Se; alone and in mixture) that are consistently present in the MME and are known to cause toxicity at fairly low concentrations as potential causes for decreased egg production in fathead minnows. The second component included evaluating the role of decreased food availability (a possible indirect effect of MME in the receiving environment) as a potential cause of decreased egg production in fathead minnows. The third and final component included examining the role of water chemistry [(increased alkalinity and dissolved organic carbon (DOC)] as potential modifying factors of chronic MME toxicity to fathead minnows. In general, my results suggest that the metals present in the MME likely do not contribute directly to decreased reproductive performance in fathead minnows during chronic exposures, under the conditions examined. Instead, the MME appears to decrease food availability, therefore indirectly influence fathead minnow egg production. Furthermore, water chemistry modifications tested in this thesis were not able to entirely mitigate the reproductive effects in fish induced by the MME, although they did improve egg production relative to unmodified MME. Metal concentrations in fish tissues were not influenced by increases to alkalinity or DOC level in the exposure water, suggesting that bioavailability of metals during chronic exposure to metal-mixtures cannot be fully explained based on our understanding of metal complexation with abiotic ligands (inorganic and organic) during single metal or acute exposures. From a regulatory perspective, water chemistry modifications may somewhat improve fathead minnow reproductive performance during chronic exposure to the MME, however the MME would still not be entirely free of effects relative to the uncontaminated water. Future studies should focus on understanding the factors responsible for decreased food availability in MME-impacted aquatic ecosystems, and further explore potential approaches for ameliorating effluent quality.

Production, egg quality, behaviour, and physical condition were compared from Wk 20 to Wk 50 among three beak- trimmed commercial laying strains, Lohmann White (LW), H & N White (HN), Lohmann Brown (LB), and a non-commercial Cross between Rhode Island Red (male) and Barred Plymouth Rock (female) in conventional cages and in floor pens. All chicks were reared in their respective environments, and 450 and 432 pullets were housed at 18 and 7 weeks of age in cages and floor pens respectively. Hens in cages were provided with 688 cm2/bird and those in pens with over 6,000 cm2/bird, both of which are more than provided by commercial standards. Body weights and eggshell weights were higher for birds in floor pens than those in cages, and although they increased with age, body weight of hens in cages decreased at Wk 50. White-egg layers (LW, HN) used perches and nest boxes more than Brown-egg layers (LB, Cross). During the laying period, mortality was higher for all strains in cages and during the rearing period mortality was higher in floor pens for LB hens but not other strains. No aggressive behaviours were found, but the frequency of gentle feather pecking and pecking at the enclosure was higher in cages than in floor pens. Feather condition deteriorated over time in cages mainly because of contact with the cage wires whereas in floor pens, feather condition of birds at Wk 20 was not different from that at Wk 50. The frequency of keel bone deformities was higher for White-egg layers than for Brown-egg layers in cages and was higher for Cross hens than other strains in floor pens. Claws were longer in cages than in the floor pens. Foot condition was worse in floor pens than in cages. The welfare indicators used in this study showed that cages restricted the hens' behaviour compared to floor pens and resulted in higher laying period mortality, reduced body weight and deteriorated feather condition than floor pens. Both systems had advantages and disadvantages in regard to the hens’ health and welfare. The use of environmental complexities was strain specific in floor pens. The environment by genotype interactions suggests that the strain should be considered when considering alternative housing systems.

Diss. (sammanfattning) Skara : Sveriges lantbruksuniv., 2002. / Härtill 4 uppsatser.