Publicação
Rational use of dietary enzymes and lipids to improve broiler performance and meat quality
| Resumo: | The importance of carbohydrate-binding modules (CBMs) and the use of novel enzymes with specific catalytic activities to improve the nutritive value of barley based diets for broilers and the effectiveness of a lipidic supplementation to improve the levels of benefic fatty acids in broilers meat remain to be investigated. In this work we studied the importance of a β-glucan binding domain (CBM11) when appended to three different enzymes (GH26GH5 and GH16, belonging to Clostridium thermocellum, and GH5, belonging to Celvibrio mixtus) to improve the nutritional quality of barley-based diets for broilers. In addition, the crystal structure and biochemical properties of a family 42 carbohydrate binding module (CBM) from Clostridium thermocellum, termed CtCBM42A, were investigated. Data presented here revealed that CBM11 has an important target effect in directing the appended catalytic modules to their target substrates, resulting in an improvement in broiler performance. However, this effect seems to be dependent on the level of supplementation. In addition, barley composition, namely its endogenous β-glucanase activity, influences the response to enzyme supplementation. Thus, exogenous enzymes were shown to be ineffective when used to supplement barleys expressing high endogenous β- glucanase activity. CtCBM42A revealed to be a type C CBM with three subdomains (α, β and γ), with affinity for arabinoxylan (arabinose side chains) and arabinan. The γ subdomain seems to dominate ligand recognition for arabinoxylan while the β and γ subdomains cooperate in arabinan recognition. Thus, CtCBM42A is potentially a good candidate for strategies aimed at improving the nutritive value of wheat-based diets for broilers. In order to improve the fatty acid profile of poultry meat, two different lipidic sources, extruded linseed and a subproduct of a marine alga (DHA goldTM), were used to supplement broiler diets. This experiment allowed the evaluation of the metabolic rates of the biosynthetic pathway of long-chain ómega 3 polyunsaturated fatty acids (LC n-3 PUFA).The supplementation of broiler diets with DHA goldTM and extruded linseed showed that conversion of linolenic acid in LC n-3 PUFA is not effective and, consequently, direct supplementation with LC n-3 PUFA seems to be the best option to enrich and improve LC n-3 PUFA in broilers meat. However, higher incorporation dosages of DHA goldTM could affect meat quality. |
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| Autores principais: | Ribeiro, Teresa Paula Costa |
| Assunto: | Broilers Plant cell wall Carbohydrate-binding modules Non-starch polysaccharides Long-chain n-3 fatty acids Meat quality Frangos de carne Parede celular Módulos de ligação a hidratos de carbono Polissacáridos não-amiláceos Ácidos gordos n-3 de cadeia longa Qualidade da carne |
| Ano: | 2011 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | The importance of carbohydrate-binding modules (CBMs) and the use of novel enzymes with specific catalytic activities to improve the nutritive value of barley based diets for broilers and the effectiveness of a lipidic supplementation to improve the levels of benefic fatty acids in broilers meat remain to be investigated. In this work we studied the importance of a β-glucan binding domain (CBM11) when appended to three different enzymes (GH26GH5 and GH16, belonging to Clostridium thermocellum, and GH5, belonging to Celvibrio mixtus) to improve the nutritional quality of barley-based diets for broilers. In addition, the crystal structure and biochemical properties of a family 42 carbohydrate binding module (CBM) from Clostridium thermocellum, termed CtCBM42A, were investigated. Data presented here revealed that CBM11 has an important target effect in directing the appended catalytic modules to their target substrates, resulting in an improvement in broiler performance. However, this effect seems to be dependent on the level of supplementation. In addition, barley composition, namely its endogenous β-glucanase activity, influences the response to enzyme supplementation. Thus, exogenous enzymes were shown to be ineffective when used to supplement barleys expressing high endogenous β- glucanase activity. CtCBM42A revealed to be a type C CBM with three subdomains (α, β and γ), with affinity for arabinoxylan (arabinose side chains) and arabinan. The γ subdomain seems to dominate ligand recognition for arabinoxylan while the β and γ subdomains cooperate in arabinan recognition. Thus, CtCBM42A is potentially a good candidate for strategies aimed at improving the nutritive value of wheat-based diets for broilers. In order to improve the fatty acid profile of poultry meat, two different lipidic sources, extruded linseed and a subproduct of a marine alga (DHA goldTM), were used to supplement broiler diets. This experiment allowed the evaluation of the metabolic rates of the biosynthetic pathway of long-chain ómega 3 polyunsaturated fatty acids (LC n-3 PUFA).The supplementation of broiler diets with DHA goldTM and extruded linseed showed that conversion of linolenic acid in LC n-3 PUFA is not effective and, consequently, direct supplementation with LC n-3 PUFA seems to be the best option to enrich and improve LC n-3 PUFA in broilers meat. However, higher incorporation dosages of DHA goldTM could affect meat quality. |
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