EFFECTS OF DIETARY SOURCES AND LEVELS OF FAT ON PERFORMANCE, NUTRIENT RETENTION AND BONE MINERALIZATION OF BROILER CHICKS FED TWO LEVELS OF CALCIUM

It is often reported that oil in full-fat seeds is poorly utilized by chicks. Studies were conducted to note the role of fat-mineral interactions for various oil and fat sources. The effects of dietary animal-vegetable blend fat (AV-blend), soybean oil, canola oil or canola soapstock at 5 or 10% inclusion level in the presence of low (0.8%) or high (1.2%) dietary calcium were investigated using broilers from 0 to 3 wk of age. Birds fed canola oil consumed significantly less feed than birds fed AV-blend fat (P   0.05). There was no effect of the dietary treatments on protein retention (> 0.05). However, there was variation among the different sources of fat in their effects on fat retention and excreta soap concentration (P < 0.01). Significant interactions were observed between the dietary sources and levels of fat on calcium and magnesium retention (P < 0.01) and phosphorus retention (P < 0.05). There were also interactions between dietary sources of fat and calcium levels on magnesium and phosphorus retention (P < 0.05) while an interaction was observed between dietary levels of fat and calcium on the metabolizable energy values of the diets (P < 0.05). Birds fed diets with animal-vegetable blend fat had the lowest bone calcium content (P < 0.01). It is concluded from this trial that the problem of fat utilization often observed when full-fat protein supplements are fed to birds, relates to factors other than the type of fat they contain, since oils extracted from these full-fat protein supplements are well utilized. Key words: Fat, calcium, broiler performance, mineral metabolism