Abstract :
Addition of fat became a common practice to increase energy density of poultry diets. Blending of unsaturated with saturated fatty acids is the best way to use fat in poultry feeding. Influence of feeding broilers on diets contained dried high saturates vegetable oil blend was evaluated in the present work by designing the experiment as five groups of one day old broilers. The first group fed on starter, grower and finisher diets during 0-2, 3-4, and 5-6 weeks of age, respectively without dried fat and it was considered as control group. Other four groups fed on diets contained normal (NRC, 1994) or extra (75 Kcal/Kg diet) ME content from dried fat along the experimental periods (0-42 days old) and on diets contained normal or extra ME content from dried fat only after two weeks of age (14-42 days old) to evaluate the effects of dried fat supplementation on growth performance, blood parameters, and carcass traits. Our results data revealed a negative effect of feeding broilers on diets contained dried high saturates vegetable oil blend with normal ME content or extra ME content on the relative growth rates, body weights, feed intakes and feed conversion ratios either along the experimental periods (0-42 days of age) or only after the starting period (14-42 days of age) compared to the control group. Dressing percentages of birds` groups fed on diets contained dried fat were lower than that of control group. However, dressing percentages of birds fed on diets contained dried fat along the experimental periods were lower than those fed on diets contained dried fat only after the starting periods. Addition of dried fat to the diets of broilers diets didn’t influence the liver and breast weights but increased thigh weight compared to the control group. Abdominal fat weights decreased by supplementation of diets with dried fat either along the experimental periods or only after the starting period. Plasma triglycerides and cholesterol levels decreased by supplementation of diets with dried fat, whereas plasma LDL levels of groups fed on diets contained extra ME and plasma VLDL levels of groups fed diets contained dried fat along the experimental periods decreased compared with those of control group. On the other hand, plasma HDL levels increased by dried fat supplementation. Glutathione reductase concentrations of plasma decreased in birds of groups fed on diets contained extra ME either along the experimental periods or only after the starting period compared with that of control group. Plasma malondialdehyde levels decreased in all groups fed on diets contained dried fat either along the experimental periods or only after the starting period. It was concluded that feeding broilers on diets rich in saturated fatty acids decreased the growth performance, dressing percentages, abdominal fat, plasma triglyerides, LDL, VLDL, glutathione reductase, malondialdehyde and increased thigh weight, plasma HDL. These effects were more pronounced when birds fed these diets from one day to 42 days old.
