En el presente estudio se realizó ecocardiografía a un grupo de pollos broiler para comparar los valores obtenidos entre las diferentes semanas de producción. Así, se realizó la evaluación ecocardiográfica de 110 pollos broiler machos de la línea Cobb Vantress aparentemente sanos durante la 4°, 5°, 6° y 7° semana de producción. Se evaluó 30 pollos la 4°, 5° y 6° semana y 20 pollos la 7° semana. Los parámetros evaluados fueron: Frecuencia cardíaca (FC), Fracción de Acortamiento (FA%), Fracción de Eyección (FE%), Tracto ventricular izquierdo en diástole (TIVd), Diámetro ventricular izquierdo en diástole (DVId); Perímetro de la pared del ventrículo izquierdo en diástole (PPVId),Tracto ventricular izquierdo en sístole (TIVs), Diámetro ventricular izquierdo en sístole (DVIs), Perímetro de la pared del ventrículo izquierdo en sístole (PPVIs), Diámetro del ventrículo derecho en diástole (RvDd) y Masa Ventrículo Izquierdo (MLV). Los resultados fueron, para FC: 381±36.13, 403±34.03, 370±44.33, 367±30.68 lat/min; FA%: 57.7±11.48, 54.8±8.67, 56.5±8.96 y 55.7±10.17; FE%: 89.1±8.15, 87.6±6.65, 88,6±7.05 y 87.7±7.44; TIVd: 0.3033±0.079, 0.315±0.075, 0.3283±0.062 y 0.3785±0.078 cm; DVId: 1.0053±0.158, 1.2137±0.159, 1.303±0.177 y 1.361±0.373 cm; PPVId: 0.2767±0.058, 0.2897±0.057, 0.363±0.065 y 0.3655±0.069 cm; TIVs: 0.4923±0.083, 0.5657±0.106, 0.608±0.104 y 0.6365±0.131 cm; DVIs: 0.432±0.150, 0.5493±0.128, 0.571±0.151 y 0.6385±0.2 cm; PPVIs: 0.5237±0.104, 0.5563±0.096, 0.686±0.136 y 0.7315±0.115 cm; RvDd: 0.2455±0.135, 0.3743±0.168, 0.527±0.14 y 0.67±0.443 cm; MLV: 3.166±1.017, 4.153±0.99, 5.428±1.232 y 6.936±2.312 g; para la 4°, 5°, 6° y 7° semana de edad respectivamente. Así mismo, se determinó la relación VD/VT, obteniéndose los siguientes resultados: 0.2034±0.019, 0.1919±0.025, 0.1857±0.02 y 0.2234±0.055; para la 4°, 5°, 6° y 7° semana de edad, respectivamente. Se encontró diferencia estadísticamente significativa (p<0.05) entre todas las semanas evaluadas en los parámetros ecocardiográficos FC, TIVd, DVId, PPVId, TIVs, DVId, PPVIs, RvDd y MLV, y para el índice cardíaco VD/VT; y no se encontró diferencia estadísticamente significativa para FA% y FE% (p>0.05) a medida que aumentaba la edad del ave. Además los valores ecocardiográficos hallados para TIVd, TIVs, DVId, DVIs, PPVId, PPVIs, y RvDd mostraron una tendencia creciente a medida que aumentaba la edad del animal.

Two consecutive experiments were conducted to evaluate the influence of dietary composition, specifically protein and amino acid profile, on performance parameters, oocyst output, and lesion development in male and female replacement broiler breeders of two different genetic lines vaccinated with a live coccidiosis vaccine. Dietary formulations were based on either breeder specific recommendations or formulations of a broiler integrator. On day 28, males of each genetic line were added to female pens to evaluate the effect of co-mingling on male performance. Lesion assessment was performed on three separate occasions per each experiment. Fecal material was collected to determine oocyst cycling patterns. During experiment 1, flock uniformity was improved (P less than/equal to 0.05) in Line A males fed the integrator diet. Increased body weight and improved uniformity of Line B females was observed with the breeder recommended diet. Co-mingling negatively impacted (P less than/equal to 0.05) male body weight. Multiple oocyst peaks were observed in both genetic lines, with the first peak occurring at approximately 16 to 18 days post placement. This first peak tended to have the highest observed magnitude and corresponded with the highest level of intestinal lesions observed during the experiment. In experiment 2, diet impacted (P less than/equal to 0.05) average body weight in Line A males, Line B males, and Line B females. Line A males fed the breeder recommended diet had increased (P less than/equal to 0.05) body weight at the termination of the experiment. Line B males and females fed the breeder recommended diet had increased (P less than/equal to 0.05) body weights throughout the experiment beginning on day 7. Negative effects (P less than/equal to 0.05) on male body weight resulting from co-mingling were observed. Oocyst peaks were delayed and at a lower magnitude in both genetic lines compared to peaks observed in experiment 1. Dietary interactions were observed in both experiments where magnitude of peak, duration of oocyst output, and severity of lesion development was influenced by diet in both male and female genetic lines. These data indicate that co-mingling negatively impacts male performance and dietary composition can impact male and female performance, oocyst cycling, and lesion development during coccidiosis vaccination in replacement broiler breeders and should be taken into consideration when rearing replacement broiler breeders.

Antibiotics have been included in poultry feeds to improve growth performance. However, it is a concern that pathogens have become increasingly resistant to antibiotics. Lysozyme is a potential replacement for antibiotics. A trial with or without heat stress was conducted to investigate different inclusion levels (0, 50, 100 and 200ppm) of lysozyme on broiler chickens. Another two trials were conducted using clean or used litter to determine the effect of 100 ppm lysozyme on broiler chickens in each period of the growth cycle. Birds fed the 50 ppm treatment had heavier weight than birds fed the 200 ppm treatment on day 35 (P<0.05). When used litter was provided, feeding lysozyme to birds from days 5-14 and throughout the trial reduced the number of E. coli in the ileum compared with feeding antibiotic to birds (P<0.05). Dietary lysozyme positively influences bacterial numbers in the gastrointestinal tract of broiler chickens.

No description available.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Feed is the largest single cost factor (60%) in production of chicken meat with cost of energy being a major consideration given that birds eat to satisfy an energy requirement. The Australian chicken meat industry is highly dependent on supply of energy from cereals such as wheat and barley that are known to vary widely in apparent metabolisable energy (AME). In contrast, sorghum is a relatively consistent source of energy. Diets for broiler chickens are comprised mainly of cereal grains, legumes and protein-rich meals of plant and animal origin. The diets are formulated to provide essential nutrients for maintenance and rapid growth of the flock as a whole. However, some dietary ingredients may also have chemical and physical properties that can be detrimental to the processes of ingestion, digestion, absorption, transport and utilisation of nutrients. Soluble non-starch polysaccharides (NSP) in cereal grains such as wheat and barley can depress digestion of energy by broiler chickens. This thesis examined the general hypothesis that the effects of soluble NSP in cereal grains on gut structure and function, digesta transit time, and gut microflora differ substantially between individual chickens within a flock, thus contributing to variation in the digestion of energy by the flock as a whole. A major goal of the research was to determine what characteristics of the gastrointestinal tract of broiler chickens were the key determinants of digestion of energy. Twelve experiments were conducted during this study. Breath tests involving measurements of carbon dioxide, hydrogen and methane were developed as noninvasive indicators of digestive function, and were used in conjunction with conventional methods for measuring energy digestion in commercial strains of chickens. Sex of the chicken had a significant effect (P<0.05) on AME values obtained for a diet based on wheat with a high soluble NSP content. Females were superior to males (14.6 vs 14.0 MJ/kg DM), but strain of chicken had no effect on AME. Villus height and crypt depth in the intestinal epithelium were measured to determine if any relationships between gut morphology and AME could explain why males and females differed. Males had significantly greater ileal villus height than females (P<0.05). In one of the two strains of chickens studied, villus heights in the duodenum and jejunum tended to be greater in males than females (0.05<P<0.10). In the second strain of chicken, villus heights in the duodenum and ileum were lower (P<0.05) than those in the first strain, with little differences observed between males and females. Crypt depth was unaffected by strain or by sex of the chickens. Thus, individual measurements of gut morphology were poor indicators of AME. Furthermore, only 33% of the total variation in apparent metabolisable energy (AME) could be accounted for by combinations of measurements of villus height and crypt depth in the duodenal, jejunal and ileal sections of the small intestine. It was concluded that other determinants of digestive capacity were collectively more important than gut morphology. Energy excretion by male chickens was observed to rise in an exponential manner relative to energy intake, whereas the increase in females was linear. It was reasoned that increased energy excretion by males could be due to increased endogenous energy losses from the distal part of the intestinal tract, reduced production of volatile fatty acids (VF A) by microbial fermentation in the caeca, or reduced absorption of VFA by caeca. These possibilities pointed to the need for a closer examination of the role of gut microbiota on the digestive function of chickens. It was also clear that further studies should differentiate between digestion of energy in the small intestine (by measurement of ileal digestible energy) and whole of tract digestion (by measurement of AME). ileal digestible energy (DE) values for wheat and barley were unaffected by sex of chickens, whereas AME values were lower in male chickens compared with females. These results suggested that the sex-specific effects of microbiota occurred mainly in the hindgut. Furthermore, the influence of the gut microbiota on between-bird variation in AME was partially dependent on the type of cereal grain used in the diet, as indicated by the observation that the differential between males and females in expiration of hydrogen and methane in the breath changed according to the type of grain consumed. That is, the metabolic activity of the gut microbiota was influenced both by the sex of the chicken and by the properties of the diet. The results of these studies provided evidence that microbial colonisation of the gut is a key determinant of the digestive function of chickens. Further work is needed to determine why microbial colonisation of the gut is variable and why it differs substantially between male and female chickens. Then it may be possible to control the initial colonisation of newly hatched chicks and to maintain a health-promoting profile throughout the life of chickens in order to enhance efficient production, and product quality and safety. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1080042 / Thesis (Ph.D.) -- University of Adelaide, Dept. of Animal Science, 2003

Hohenheim, Univ., Diss., 2008.

Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 80-89).

Hohenheim, Univ., Diss., 2005.

Tierärztl. Hochsch., Diss., 2004--Hannover.

Made available in DSpace on 2014-06-11T19:27:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-29Bitstream added on 2014-06-13T19:55:41Z : No. of bitstreams: 1 barreiro_fr_me_jabo.pdf: 251881 bytes, checksum: 48e1f2d6aae2e7f23f8a2781b2726622 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo desse experimento foi pesquisar a eficiência do uso de cloro na água de frangos de corte durante o período de jejum pré-abate, para a diminuição de microrganismos como Escherichia coli e enterococos no inglúvio e conteúdo cecal das aves, pois se ocorrer diminuição na quantidade desses microrganismos, é muito provável que os patogênicos também seguirão essa mesma tendência. Também foi avaliado se o cloro associado ao jejum causou algum dano intestinal que poderia facilitar a disseminação de microrganismos para a carcaça. Foram utilizadas 40 aves de corte da linhagem Cobb, distribuídas em boxes de acordo com o tratamento (sem jejum no início do período pré-abate, 12 horas de jejum sem adição de cloro, 12 horas de jejum com adição de cloro, sem jejum no final do período pré-abate). Foram coletadas amostras de conteúdo cecal e inglúvio, para análise microbiológica; e o duodeno e jejuno para análise morfológica, após a eutanásia de 10 aves de cada tratamento. Foi realizada a determinação dos números mais prováveis (NMP) de Escherichia coli e enterococos nas amostras coletadas e a mensuração da concentração de cloro residual livre na água. Também foram feitas a morfometria e a microscopia eletrônica de varredura do duodeno e jejuno. Pode-se concluir que o cloro foi eficaz na diminuição dos microrganismos no inglúvio das aves, sendo realmente necessário associar o jejum com a desinfecção do inglúvio através do cloro na água, já que o tratamento levando em consideração apenas o jejum fez com que o NMP de enterococos e Escherichia coli no inglúvio aumentasse, representando assim, maior risco de contaminação da carcaça durante o seu processamento no abatedouro. O cloro adicionado à água não danificou a mucosa do duodeno e jejuno, sendo importante sua adição durante o jejum pré-abate, pois melhorou a integridade da mucosa intestinal / The objective of this experiment was to test whether the addition of chlorine to drinking water during a 12-hour pre-slaughter feed withdrawal period was efficient in reducing the quantities of microorganisms, such as Escherichia coli and Enterococci, in broiler crops and ceca. Reduction of these microorganisms would likely also reduce pathogenesis post-slaughterhouse. It was also investigated if the chlorine caused some intestinal damage that could cause the dissemination of microorganisms to the carcass. A total of 40 Cobb male broilers were distributed in pens accord to the treatment (without feed withdrawal at the beginning of the pre-slaughter period, after feed withdrawal without chlorine additon, after feed withdrawal with chlorine additon, and without feed withdrawal after the pre-slaughter period). Samples of crop and cecal content were collected for microbiological analysis; and duodenum and jejunum for morphological analysis from 10 birds in each treatment. The Most Probable Number (MPN) of E. coli and Enterococci in the collected samples, the measure of the free residual chlorine in water; and the morphometry and scanning electron microscopy from duodenum e jejunum were determined. Chlorine was efficient in reducing the quantities of microorganisms in crops. Therefore, pre-slaughter feed withdrawal should be coupled with crop disinfection; because pre-slaughter feed withdrawal increases the MPNs of Enterococci and E. coli, presenting a higher risk for carcass contamination during slaughterhouse processing and, consequently, a higher risk for public health. The chlorine added to water did not damage the duodenum and jejunum mucosa and should be added during the pre-slaughter feed withdrawal because improved the intestinal mucosa integrity