Abstract
Effects of three kinds of diets, high carbohydrate (HC), isoenergetic high fat (HF1), and highenergetic high fat (HF2) on dietary energy and protein utilization were studied for Fischer rats at ambient temperature of 23°C or 8°C for 21 days. All of the three experimental diets contained 15% of casein as energy source. Only HF1 contains high level of cellulose of which energy content is equal to that of HC. To clarify effects of energy dilution by cellulose in the high fat diet, this study was conducted in the cold environment in which rats consumed more energy.
In all the experimental groups, the levels of body weight gains for 21 days were almost the same. However, the high fat diets caused significant increase in body fat and decrease in body nitrogen retention as compared with that of HC at 23°C. All the rats at 8°C showed significant decrease in body fat. The extent was the greatest in rats fed HF1. The body nitrogen retentions were almost the same in the three dietary groups at 8°C. The apparent protein digestibility of HF1 group was significantly lower than that of the others, while the apparent fat digestibility did not change in HF1 and HF2. The cold environment did not affect the digestibilities of fat and protein. These results suggested that cellulose might decrease body fat of rats fed HF1.
