Reducción de la disposición de grasa abdominal en el pollo de carne mediante la modificación del perfil de ácidos grasos de la dieta
Reduction of abdominal fat deposition in Broiler chicken by dietary fatty acid profile modification.
Nieves Crespo Alcarria
Genetic selection and use of energetic rations has led to an increase in broiler growth. Fifty years ago chickens spend 85 days to reach 1.800g of body weight. Nowadays this period has been reduced to 36 days and moreover feed conversion ratio has been improved in more than 50%. However, as a consequence of this higher growth it has been produced higher carcass fat deposition.
In the processing plant, carcass fat constitute important economic loses. If we also take into account the higher acceptance of low fat content products by consumer, this justifies interest to obtain a reduction in body fat deposition of chickens.
Several works performed in mammals and some in chickens suggest that substitution of saturated fat by polyunsaturated fat in feed could reduce carcass fat deposition.
In the present work the effect of feed with different fatty acid profile on fat deposition and lipid metabolism in the chicken was studied. Four types of fat with different saturation level were used at 10% inclusion level. Tallow was added as a source of saturated fatty acid, olive oil as a source of monounsaturated fatty acids, sunflower oil as a source of polyunsaturated fatty acids of n-6 series and linseed oil as a source of polyunsaturated fatty acids of n-3 series.
Main objectives were to determine the effect of different dietary fats on:
? Performance parameters of broiler chickens.
? Body and abdominal fat deposition and fat deposition in other separable fat depots.
? Energy, protein, fat and fatty acid deposition.
? Hepatic lipid synthesis.
? Biochemical parameters related with fat deposition in broiler chicken (VLDL, glucose and insulin).
Obtained results show that diets rich in polyunsaturated fatty acids improve feed conversion ratio in about 10%.
Percentage of abdominal fat and other separable fat depots was significantly reduced with diets rich in polyunsaturated fatty acids. This reduction reached values of about 30g of adipose tissue.
On the other hand, higher fatty acid beta-oxidation was obtained in broilers fed diets rich in polyunsaturated fatty acids which could lead to lower energetic efficiency of feed. Results of hepatic fatty acid synthesis showed higher levels in broilers fed diet with added linseed oil, respect to the rest of the diets.
It was concluded that diets rich in polyunsaturated fatty acids reduce fat deposition in broiler chicken. Results suggest that the main cause of fat reduction by polyunsaturated fatty acids is not a modification in lipogenesis level but also the higher fatty acid beta-oxidation observed with these diets, that would lead to lower energetic efficiency of the diet to fat deposition. Taking into account the low contribution of endogenous fatty acid synthesis to fat deposition in broilers fed high fat diets, any modification in this endogenous activity would not lead to a modification in body fat deposition as it would be compensate by direct dietary fat deposition.
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Advisor:Esteve Garcia, Enric
School:Universitat Rovira i Virgili
Source Type:Master's Thesis
Keywords:departament de bioquímica i biotecnologia
Date of Publication:09/27/2004