Effects of hardened palm oil and protein on the pathological and hematological characteristics of ducklings fed rapeseed oil.

The effects of the protein and hardened palm oil (HPO) content of the diet on the pathological and hematological characteristics of ducklings fed rapeseed oil (RSO) were investigated. Groups were fed for 3 weeks a basal diet containing a mixture of either HPO and soybean oil (SBO), RSO and SBO or RSO and HPO, together constituting 60% of total diet calories. Each fat mixture was given with either 23 cal% casein, 32 cal% casein or 32 cal% soyprotein. Growth was better with 32 cal% protein than with 23 cal% protein. The mixture RSO-SBO produced growth retardation irrespective of diet protein, which was largely overcome when HPO replaced the SBO in the mixture. RSO-SBO also produced an increased hematocrit, hydropericardium, vacuolar changes in the heart and skeletal muscles, cirrhotic changes in liver and hemopoietic activity in liver and spleen. The pathological changes were less severe with the higher-protein than with the lower-protein diet. The hydropericardium, liver and splenic changes almost disappeared as HPO replaced SBO in the fat mixture, but the skeletal muscles and heart changes persisted. The latter aggravated when the diet contained the lower protein level. Hemoglobin values were normal with all diets. Total serum protein was not changed by the RSO-SBO fat mixture, but the albumin was decreased and the globulin increased. The decrease in albumin was hardly evident with 32 cal% soyprotein. The addition of HPO to RSO corrected the decrease in albumin but did not decrease the globulin concentration. Total serum protein concentration was, therefore, raised. The results suggest an impairment of the albumin synthesis in the liver as a possible factor predisposing to the hydropericardium in RSO-fed ducklings.