This study was conducted with the aim to investigate the efficacy of exogenous enzyme supplementation in releasing metabolisable energy in broiler feeds. Two performance trials were conducted during this study. Effects were measured in terms of the body weight gain, feed intake, feed conversion ratio, mortality and production efficiency factor in broilers. Correct interpretation and practical application of the positive effects of exogenous enzyme supplementation to commercial broiler feeds can aid nutritionists to develop nutritionally balanced broiler feeds at lower costs. The negative effects of anti-nutritional factors in broilers feeds can be greatly reduced with the strategic use of exogenous enzyme addition to the feed. In the first performance trial, four treatment feeds were fed to broilers. The Positive control feed was a balanced diet, formulated according to standard nutrient specifications used by Daybreak Farms, with only the metabolisable energy marginally lower than the standard to ensure that energy was the first limiting nutrient. Nutrient specification met or exceeded recommendations by the NRC (1994). A Negative control feed, similar to the Positive control, was formulated with 0.35 MJ ME / kg feed less than the Positive control. An Avizyme treatment and a Hemicell treatment were formulated similar to the Negative control, with the addition of 0.05% Avizyme and 0.0125% Hemicell to the respective treatments. The addition of Avizyme and Hemicell to the respective treatments was hypothesised to release an additional 0.35 MJ ME / kg feed. Four thousand three hundred and twenty day-old Ross 788 chicks were randomly divided into four treatment groups, each with eight replicates and 135 birds per replicate for the first seven days. After seven days birds were reduced to 126 birds per replicate. In the second performance trial, five treatment feeds were fed to broilers. The Positive control feed was a balanced diet, formulated according to standard nutrient specifications used by Daybreak Farms, with only the metabolisable energy marginally lower than the standard to ensure that energy was the first limiting nutrient. Nutrient specification met or exceeded recommendations by the NRC (1994). Results of the first performance trial indicated that more than the hypothesised 0.35 MJ ME / kg feed was being released from the feed with exogenous enzyme addition. Subsequently, the difference in metabolisable energy between the Negative control and Positive control treatments were increased for the second trial. A Negative control feed, similar to the Positive control, was formulated with 0.45 MJ ME / kg feed less than the Positive control. An Avizyme treatment and a Hemicell treatment were formulated similar to the Negative control, with the addition of 0.05% Avizyme and 0.0125% Hemicell to the respective treatments. A Combination treatment was formulated similar to the Negative control, with the addition of both 0.05% Avizyme and 0.0125% Hemicell to the feed. Seven thousand five hundred and sixty day-old Ross 788 chicks were randomly divided into five treatment groups, each with 12 replicates and 126 birds per replicate. For both trials, birds were housed in environmentally controlled houses with a similar lighting schedule and ad libitum access to feed and water. Body weights, feed intake and mortality were recorded weekly for the duration of the five week performance trials. The data was statistically analysed, using the general linear model function in SAS (Statistical Analysis Systems, 1989; Statistical Analysis Systems, 1994). Fischer’s protected test was used for the post hoc multiple comparison test. Repeated tests were included in the model. The confidence interval was set at 95%. Initial body weight was tested as a covariate in all the analyses. Incorrect dosing of the trial feeds during the first performance trial prevented the evaluation of the treatments for the entire 35 day period. The difference between the Positive control and the Negative control treatments were not large enough to enable the exact determination of the amount of metabolisable energy that the Avizyme released in the feed. It could, however, be concluded that Avizyme addition to a broiler feed increased broiler production efficacy. The Avizyme treatment was contributed at least 0.35 MJ ME / kg feed during the trial released more than 0.35 MJ ME / kg feed during the extended starter phase of the trial. The above mentioned conclusions served as a motivation to increase the metabolisable energy difference between the Positive control and the Negative control treatments for the next performance trial. Addition of Hemicell to the feed contributed 0.35 MJ ME / kg feed over a five week growing period. With the second performance trial, the Avizyme and Hemicell treatments released an additional 0.45 MJ ME / kg feed, supported by broiler production variables similar to the Positive treatment. The Combination treatment was shown to release more than 0.45 MJ ME / kg feed and significantly increased broiler performance. It was concluded that the combination of Hemicell and Avizyme in a broiler ration had a positive synergistic effect on each other in the young broiler, indicating that exogenous enzymes could be more effective in younger broilers. Although exogenous enzymes resulted in the release of a significant amount of additional metabolisable energy in the feed, the addition of these enzymes should undergo economical evaluation to ensure that the addition of these enzymes is viable under commercial circumstances. Addition of Avizyme with a calculated energy contribution of 0.35 MJ ME / kg and 0.45 MJ ME / kg to the feed realised an income over feed cost (IOFC) of 25 c / kg live weight and 4 c / kg live weight, respectively, during the five week period. The Hemicell treatment showed a negative IOFC (suggesting that Hemicell inclusion will decrease profit) of 24 c / kg live weight during the first four weeks of the first production trial and an IOFC of 2 c / kg live weight during the five week period of the second trial. The combination of both enzymes in the feed returned an IOFC of 16 c / kg live weight. In general the income over feed cost was the highest during the starter phase because of a higher efficacy of exogenous enzyme addition in younger broilers. / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Animal and Wildlife Sciences / unrestricted

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-05-23T13:07:09Z No. of bitstreams: 1 Anna Carolina da Silva.pdf: 1738062 bytes, checksum: 8a7486e43be42611cf895a1cc7556737 (MD5) / Made available in DSpace on 2016-05-23T13:07:09Z (GMT). No. of bitstreams: 1 Anna Carolina da Silva.pdf: 1738062 bytes, checksum: 8a7486e43be42611cf895a1cc7556737 (MD5) Previous issue date: 2013-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The xylanases randomly hydrolyzes β-1,4-glycosidic bonds of xylan, producing xylooligomers of different sizes, therefore, these enzymes can be used in the diet of monogastric animals to hydrolyze the non-starch polysaccharides like β-glucans and arabinoxylans found in cereals, improving feed conversion and weight gain by decreasing the anti-nutritional effects caused by xylan. All sources of xylanase, filamentous fungi are interesting from the industrial viewpoint, because they have a high enzyme production when compared to other micro-organisms in fermentation processes. The production cost of the enzyme is concentrated mainly in the post-fermentation processes in an attempt to obtain pure enzyme. The application of extractive fermentation decreases cost by the reduction in purification steps of the molecule. The objective of this work by producing xylanase in ATPS extractive fermentation by Aspergillus tamarii URM 4634, scale production in bioreactors, the enzyme partially characterize and evaluate the influence of their activity in monogastric digestion. The xylanase had a better performance at acidic pH (3.6) and 90 ° C, proving to be stable to pH and temperature, maintaining its activity above 40 and 50% respectively, for 180 minute test. Most ions and inhibitors tested did not significantly alter its activity. The xylanase has great potential to be applied in the feed industry for its features and especially for having behaved positively in simulated gastric digestion. / As xilanases hidrolisam aleatoriamente ligações β-1,4-glicosídicas da xilana, produzindo xilooligomêros de diferentes tamanhos; por esta razão, essas enzimas podem ser utilizadas na dieta de animais monogástricos para hidrolisar os polissacarídeos não-amiláceos como β-glucanos e arabinoxilanos encontrados em cereais, melhorando a conversão alimentar e o ganho de peso, por diminuírem o efeito anti-nutricional causado pela xilana. De todas as fontes de xilanases, os fungos filamentosos são interessantes do ponto de vista industrial, pelo fato de terem alta produção de enzimas quando comparados a outros micro-organismos em processos fermentativos. O custo de produção da enzima concentra-se, principalmente, nos processos pós-fermentativos na tentativa de se obter a enzima pura. A fermentação extrativa diminui o custo pela redução nas etapas de purificação da molécula. Objetivou-se com este trabalho produzir xilanase por fermentação extrativa em sistemas de duas fases aquosas (SDFA) por Aspergillus tamarii URM 4634, escalonar a produção em biorreatores, caracterizar parcialmente a enzima e avaliar a influência da sua atividade na digestão monogástrica. A xilanase produzida teve melhor desempenho em pH ácido (3,6) e a 90 °C, demonstrando ser estável ao pH e à temperatura, mantendo sua atividade acima dos 40 e 50%, respectivamente, nos 180 minutos de ensaio. A maioria dos íons e substâncias inibidoras testadas não alterou significativamente sua atividade. A xilanase tem grande potencial para ser aplicada na indústria de rações por suas características e principalmente por ter comportado positivamente na simulação da digestão gástrica.

Abstract available in the Current Developments in Nutrition.

<p dir="ltr">For this dissertation, two experiments were conducted to evaluate the effects of a multienzyme mix and partially defatted black soldier fly larvae meal on chicken coccidiosis, focusing on growth performance, intestinal health, and microbiota dynamics. Experiment 1 examined the growth performance, nutrient utilization, microbiota modulations, and other gut health-related indicators of broiler chickens under coccidia challenge, with dietary supplementation of multienzyme, including phytase, xylanase, β-glucanase, amylase, hemicellulase, and pectinase. Ross 308 broilers were assigned to 4 treatments in a 2×2 factorial arrangement comprising of 0 or 50 g·kg-1 multienzyme and oral challenge with PBS or mixed Eimeria spp. oocysts (250,000 E. acervulina, 50,000 E. maxima, and 50,000 E. tenella). Multienzyme reduced (P < 0.05) Eimeria-induced loss in feed efficiency and nutrient utilization, partially explained by reduced decrease of b0,+ amino acid transporter in jejunum. Multienzyme suppressed (P < 0.05) the overexpression of interleukin-8 in the duodenum and jejunum and ameliorated (P = 0.05) the decreased expression of antioxidant heme oxygenase 1 in ileum induced by Eimeria infections. Multienzyme facilitated (P < 0.01) the bloom of short-chain fatty acid-producing and fiber-degrading microbes. The study concluded that multienzyme supplementation partially alleviated the adverse effects of Eimeria infections through various mechanisms, including enhanced nutrient utilization, reduced local inflammations, and restoration of microbial homeostasis. Experiment 2 investigated the growth dynamics, nutrient assimilation, and gut health responses of broiler chickens under coccidia challenge, with dietary supplementation of partially defatted black soldier fly larvae meal (pBSFLM) with increasing concentrations of 0, 60, 120 g/kg. During the infection phase (from d 13 to 19), interactions between Eimeria and pBSFLM revealed significant associations with gain to feed ratio (G:F) (P < 0.05) and cecal interferon-γ (IFN-γ, P < 0.05), while showing tendencies for crypt depth (P = 0.088) and cecal acetate concentration (P = 0.06). The incremental inclusion of pBSFLM demonstrated a negative effect on the G:F and the generation of IFN-γ and acetate in the ceca during coccidia challenge. Conversely in the non-challenged birds, the impact of dietary pBSFLM varied from neutral (e.g. G:F) to potentially advantageous (e.g. acetate). Challenged broilers exhibited decreased (P < 0.01) BW, feed intake (FI), G:F, as well as the apparent ileal digestibility (AID) and total tract nutrient utilization (ATTU) of DM, gross energy (GE), and nitrogen (N). Eimeria challenge led to reduced (P < 0.01) serum carotenoid concentrations, increased (P < 0.01) ileal crypt depth (CD), and an increase in the generation of branched-chain fatty acids, specifically isobutyrate (P = 0.059) and isovalerate (P < 0.05) in the ceca. Dietary pBSFLM addition caused a linear reduction (P < 0.05) in BW, FI, G:F, and N utilization. Furthermore, a tendency (P < 0.06) was observed where pBSFLM linearly decreased the villi height: CD ratio and reduced goblet cell density in the villi. Results from this experiment reveal that higher levels of pBSFLM supplementation, especially at 12%, had detrimental effects on growth, ileal morphology, cecal acetate production, and downregulated the expression of key cytokines in response to coccidia infection. In summary, these studies shed light on the multifaceted effects of dietary interventions on Eimeria infections in broiler chickens, with a specific emphasis on growth, nutrient utilization, and indicators of gut health.</p>