Studies of digestibility in growing pigs fed final and high-test sugarcane molasses

Ten barrows of 35 kg of weight were used to study the rectal digestibility of five diets containing different ratios of sugarcane high-test and final molasses (75:0, 60:15, 45:30, 30:45 and 15:60 respectively). The diets were supplemented with fishmeal and Saccharomyces yeast as protein source, and daily feed intake was ad libitum. Rectal digestibility of DM, N, and energy were 91.2, 84.4 and 85.7; 90.5, 84.1 and 90.7; 89.8, 83.2 and 89.1; 88.8, 84.2 and 90.0 and 87.8, 92.8 and 88.3% in the same order. Significant differences (P < 0.05) among diets were found for energy digestibility, although DM, organic matter, and N digestibility tended to decrease with increasing levels of final molasses in the diet. A linear response was found in feed consumption (R-2, 0.837; P < 0.029), which was highest and lowest for diets containing high-test and final molasses (2.4 and 1.9 kg DM/animal, respectively). According to the results, it is not possible to consider that rectal digestibility of nutrients in the diets are directly responsible per se for performance traits determined by a high proportion of final molasses in the feed. Other causes, such as the low energy density of final sugar molasses, should be directly involved in this status, which could be aggravated if animals do not increase their voluntary feed intake.