학술논문
Use of soybean acid oil and palm fatty acid distillate in broiler chicken diets
Document Type
Dissertation/Thesis
Author
Source
TDX (Tesis Doctorals en Xarxa)
Subject
Language
English
Abstract
La incorporación de materias grasas en los piensos para pollos de carne tiene como principal objetivo incrementar su concentración energética. El aceite ácido de soja (SA) y los destilados de ácidos grasos de palma (PFAD) son subproductos derivados de la refinación del aceite de soja (S) y del aceite de palma (P), respectivamente. Éstos tienen una composición en ácidos grasos (AG) similar al aceite de origen, pero diferente estructura molecular (triacilgliceroles, TAG; diacilgliceroles, DAG; monoacilgliceroles, MAG; ácidos grasos libres, AGL). Puesto que su elevado contenido en AGL puede limitar su utilización por parte del animal, el objetivo global de esta tesis fue investigar el uso potencial de SA y PFAD combinados con aceites convencionales de distinto grado de saturación en la alimentación de pollos de carne, en piensos de iniciación y de crecimiento-acabado, profundizando en los procesos de digestión y absorción de la fracción lipídica. Se realizó un primer estudio in vitro con el objetivo de evaluar la hidrólisis y la bioaccessibilidad de SA, PFAD y sus respectivos aceites crudos. Los resultados obtenidos coincidieron con los derivados de estudios in vivo, determinándose que la bioaccessibilidad es más limitante que la hidrólisis en la utilización de los aceites. La evaluación de la bioaccessibilidad permitió corroborar que la utilización de los aceites se ve más influenciada por el grado de saturación que por los AGL de la dieta. En el segundo y el tercer ensayo se estudió el efecto de reemplazar S por PFAD y P por SA, sobre el contenido en fracciones lipídicas y la digestibilidad de los AG a lo largo del tracto intestinal y en las heces, en pollos de carne de 11 y 35 días (d). Los resultados indican que el íleon posterior es el segmento más importante para evaluar la absorción final de la grasa. Con respecto a la absorción de los AG, se observó que a medida que aumentaba el contenido de AG saturados (AGS) y AGL de la dieta, la absorción de grasa en pollos de iniciación disminuía y era más lenta. Conforme aumentaba la edad, la absorción de AGS y AGL en el yeyuno mejoraba e incrementaba la contribución del íleon anterior en la absorción de los AG. A 11d, la utilización de la grasa disminuyó al incluir PFAD al 6% o mezclado con S; sin embargo, mejoró con la substitución de P por SA, aunque no alcanzó el nivel de absorción de la dieta S. A 35 d, el uso de PFAD mezclado con S (2% y 4%, respectivamente) dio lugar a una alta utilización de la grasa, indicando que su incorporación en la dieta es una alternativa viable, siempre y cuando tenga al menos una relación de AG insaturados:AGS de 2,6 y no supere el 30% de AGL de la dieta. La utilización de la grasa obtenida con SA al 6% o con la mezcla de P y SA (2% y 4%, respectivamente) fue similar a la de S al 6%. En las dietas de crecimiento-acabado, cuando ambos subproductos se mezclaron con los aceites convencionales (aumentando AG insaturados:AGS y TAG:AGL en la dieta) se observó un sinergismo en los valores de energía metabolizable aparente. Los resultados obtenidos apuntan a que una forma adecuada de introducir estos subproductos en las dietas de pollos es a través de mezclas con grasas convencionales. Además, la digestibilidad de los AGL de la dieta fue mayor cuando estos provenían de una grasa insaturada que de una saturada. Estas estrategias implican una mejora de la rentabilidad, y una forma de reciclar estos subproductos, disminuyendo su impacto medioambiental.
The supplementation of fats and oils in broiler chicken feeds is a common practice to increase the energy content of diets and provide essential fatty acids. Soybean acid oil (SA) and palm fatty acid distillate (PFAD) are by-products derived from the soybean oil (S) and palm oil (P) refining industry, respectively. They have similar fatty acid (FA) composition to their respective crude oil, but different molecular structure (triacylglycerols, TAG; diacylglycerols, DAG; monoacylglycerols, MAG; free fatty acids, FFA). Its high content in FFA, represents a limitation to upcycle these by-products in the animal feed industry. The global aim of this thesis was to investigate the potential use of SA and PFAD in blends with conventional oils with different saturation degree in broiler chicken diets, focusing the study on the fat intestinal absorption in both starter and grower-finisher chickens. In the first experiment, in vitro methodologies were performed with the aim to evaluate the hydrolysis and bioaccessibility of SA, PFAD, and their respective crude oils. The results supported the findings reported in in vivo studies, the bioaccessibility was the most limiting step in oil digestion, not the hydrolysis. Moreover, the assessment of the bioaccessibility corroborated that the FFA level of dietary fat influences fat utilization less than its saturation degree. The second and the third trial were conducted in parallel in order to study the effect of the replacement of S by PFAD and P by SA on lipid-class content and FA digestibility along the intestinal tract (upper and lower jejunum, upper and lower ileum) and in the excreta in broiler chickens at 11 and 35 days (d). The assessment of the lipid-class content and the apparent FA digestibility in the different intestinal segments was crucial for a better understanding of the utilization of different fat sources in broiler chickens, being the lower ileum the most important segment to evaluate the final fat utilization. Concerning the absorption dynamics, as the saturated FA (SFA) and FFA dietary content increased, the absorption of dietary fat was reduced and delayed in starter chickens. On the other hand, as the age of the chicken increased, was seen an improvement in the absorption of SFA and FFA in the jejunum and an increase in the contribution of the upper ileum to FA absorption. The results revealed that for 11-d-old broiler chickens the inclusion of PFAD at 6% or blended with S impaired fat utilization, whereas the replacement of P by SA improved FA absorption, although did not reach the fat absorption obtained with S. In broiler chickens at 35 d, the inclusion of PFAD blended with S (2% and 4%, respectively) represented a suitable fat alternative, when the blend has from 2.6 unsaturated FA:SFA ratio and the FFA% does not exceed 30%, which led to adequate fat utilization. Moreover, the use of SA at 6% or the blend between P and SA (2% and 4%, respectively) led to obtaining similar fat utilization than S at 6%. Furthermore, in 35-d-old broiler chickens, the synergism obtained in the apparent metabolizable energy of diets when both by-products were blended with the conventional oils suggested that the increase in both the unsaturated FA:SFA ratio and the proportion of TAG to FFA in the diet is a good way to introduce these by-products in broiler chicken diets. An interesting result was that the dietary FFA digestibility was higher when FFA were provided from unsaturated rather than saturated fat sources. This potential strategy to use SA and PFAD implies a reduction in economic costs of feed and a way to upcycle them decreasing their environmental impact.
Universitat Autònoma de Barcelona. Programa de Doctorat en Producció Animal
The supplementation of fats and oils in broiler chicken feeds is a common practice to increase the energy content of diets and provide essential fatty acids. Soybean acid oil (SA) and palm fatty acid distillate (PFAD) are by-products derived from the soybean oil (S) and palm oil (P) refining industry, respectively. They have similar fatty acid (FA) composition to their respective crude oil, but different molecular structure (triacylglycerols, TAG; diacylglycerols, DAG; monoacylglycerols, MAG; free fatty acids, FFA). Its high content in FFA, represents a limitation to upcycle these by-products in the animal feed industry. The global aim of this thesis was to investigate the potential use of SA and PFAD in blends with conventional oils with different saturation degree in broiler chicken diets, focusing the study on the fat intestinal absorption in both starter and grower-finisher chickens. In the first experiment, in vitro methodologies were performed with the aim to evaluate the hydrolysis and bioaccessibility of SA, PFAD, and their respective crude oils. The results supported the findings reported in in vivo studies, the bioaccessibility was the most limiting step in oil digestion, not the hydrolysis. Moreover, the assessment of the bioaccessibility corroborated that the FFA level of dietary fat influences fat utilization less than its saturation degree. The second and the third trial were conducted in parallel in order to study the effect of the replacement of S by PFAD and P by SA on lipid-class content and FA digestibility along the intestinal tract (upper and lower jejunum, upper and lower ileum) and in the excreta in broiler chickens at 11 and 35 days (d). The assessment of the lipid-class content and the apparent FA digestibility in the different intestinal segments was crucial for a better understanding of the utilization of different fat sources in broiler chickens, being the lower ileum the most important segment to evaluate the final fat utilization. Concerning the absorption dynamics, as the saturated FA (SFA) and FFA dietary content increased, the absorption of dietary fat was reduced and delayed in starter chickens. On the other hand, as the age of the chicken increased, was seen an improvement in the absorption of SFA and FFA in the jejunum and an increase in the contribution of the upper ileum to FA absorption. The results revealed that for 11-d-old broiler chickens the inclusion of PFAD at 6% or blended with S impaired fat utilization, whereas the replacement of P by SA improved FA absorption, although did not reach the fat absorption obtained with S. In broiler chickens at 35 d, the inclusion of PFAD blended with S (2% and 4%, respectively) represented a suitable fat alternative, when the blend has from 2.6 unsaturated FA:SFA ratio and the FFA% does not exceed 30%, which led to adequate fat utilization. Moreover, the use of SA at 6% or the blend between P and SA (2% and 4%, respectively) led to obtaining similar fat utilization than S at 6%. Furthermore, in 35-d-old broiler chickens, the synergism obtained in the apparent metabolizable energy of diets when both by-products were blended with the conventional oils suggested that the increase in both the unsaturated FA:SFA ratio and the proportion of TAG to FFA in the diet is a good way to introduce these by-products in broiler chicken diets. An interesting result was that the dietary FFA digestibility was higher when FFA were provided from unsaturated rather than saturated fat sources. This potential strategy to use SA and PFAD implies a reduction in economic costs of feed and a way to upcycle them decreasing their environmental impact.
Universitat Autònoma de Barcelona. Programa de Doctorat en Producció Animal