Nitrogen utilization and performance of pigs given diets containing a dried or undried fermented blood/molasses mixture

The effect of feeding either a dried or undried fermented blood/molasses (80 : 20 w/w) mixture to pigs as a source of nitrogen was evaluated in two experiments. In Experiment 1, twelve pigs (initial weight 20.6, sd 0.05 kg) were randomly assigned to one of two treatments in a 2 × 2 factorial arrangement with main effects being form of fermented blood/molasses mixture (dried versus undried) and sex (male versus female). There were six pigs in each treatment. Fermented blood/molasses mixture was incorporated at a level of 60 g kg−1 to partially replace soybean meal in each case. Pigs were housed individually and fed ad libitum. Water was also available in unlimited quantities at 8:00, 13:00, and 17:00 h daily. Daily gain, feed intake, and feed efficiency were measured over a 35 day experimental period. In Experiment 2, four barrows (initial weight 58, sd 3.1 kg) were fed individually in metabolic cages according to a 4 × 4 Latin square design. The treatments compared were: (1) maize + soybean meal, (2) maize + soybean meal + 100 g kg−1 dried fermented blood/molasses mixture, (3) maize + soybean meal + 100 g kg−1 undried fermented blood/mixture, (4) Maize alone. All diets contained adequate minerals and vitamins for growing pigs. The aim of Experiment 2 was to investigate the digestibility and utilization of nitrogen (N) in fermented blood/molasses mixture. The results of Experiment 1 showed that daily gain and feed efficiency were not affected (P > 0.05) by the form in which the mixture was given. However, feed intake was greater (P < 0.05) for the pigs fed the diet containing undried fermented blood/molasses mixture. Furthermore, females were more efficient (P < 0.05) in the utilization of feed than males. The results of Experiment 2 showed the digestibility of N in diets containing blood/molasses mixture were similar to that of the maize–soybean meal diet (P > 0.05). In addition, nitrogen retention (NR) and biological value (BV) were comparable among diets containing either fermented blood/molasses mixture or soybean meal. The absolute biological value for the maize–soybean meal diet was relatively lower (43.8%) than those of diets which contained dried (49.8%) and undried (54.4%) blood/molasses mixture. The digestibility of N in maize, soybean meal, dried, and undried blood/molasses mixture was 66.5%, 91.6%, 85.3%, and 87.3% respectively. It is concluded that the utilization of N in fermented blood/molasses mixture is high in growing pigs and not affected by the form (dried or undried) in which it is incorporated in the diets. Therefore, the results suggest that fermented blood/molasses mixture does not have to be dried before it is incorporated in pig diets.