UTILIZATION OF SUGAR CANE FINAL MOLASSES BY THE PIG: ENERGY METABOLISM
A sample of sugar cane final molasses (82.5% dry matter) contained the following components (percent of dry matter): ash, 11.4; sucrose, 32.8; fructose, 21.1; glucose, 7.4; and unidentified organic matter, 27.3. Three diets were prepared by mixing soybean meal with either starch, molasses, or a mixture of sugars to simulate those in the molasses. The digestible and metabolizable energy values of the diets were measured with pigs of approximately 35 kg liveweight. The digestible and metabolizable energy values of the molasses were 12.3 and 11.8 MJ/kg dry matter, respectively. The metabolizable energy values of the sugar mixture and the unidentified organic matter were 16.5 and 6.1 MJ/kg, respectively. The heat production of pigs of approximately 13 kg liveweight was measured following the consumption of the three diets, and their energy retention was calculated. The metabolizable energy from the molasses was retained at least as well as that from the other two diets, showing that the mixture of glucose and fructose absorbed from the molasses was an efficient metabolic fuel. These observations suggest that the reduction in performance which usually follows the substitution of molasses for cereals in pig diets is due to the low metabolizable energy value of the molasses coupled with failure of the pigs to increase feed consumption to maintain metabolizable energy intake. Key words: Molasses, pigs, digestible energy, metabolizable energy, respiration calorimetry