Nutritional evaluation of the white‐rot fungus Sporotrichum pulverulentum as a feedstuff to rats, pigs, and sheep

Abstract

AbstractThe production of single‐cell protein (SCP) based on cheap carbon sources such as spent liquor from paper mills is of interest for different reasons. The White‐rot fungus (Sporotrichum pulverulentum) has earlier been shown to degrade cellulose and lignin. The nutritive value of this fungus was investigated with rats, pigs, and sheep. The effect of different drying process was evaluated on rats. Experiments with piglets, growing pigs, and sheep were aimed at getting primary information on nutritive parameters with domestic animal species, Chemical analysis of S. pulverulentum showed that the sum of the amino acids corresponded to 70% and ammonia, GABA, and glucosamine to 20% of its crude protein content. Differences between drying treatments in their effect on protein digestibility were not noted. From a protein quality viewpoint, a tendency toward superiority was noted for two of the drying processes. The amino acid digestibility of S. pulverulentum was inferior to values for soybean oil meal given in textbooks. The piglet experiment confirmed the lower nutritive value of S. pulverulentum compared with soybean oil meal. in the piglet stage a content of metabolizable energy of S. pulverulentum was found which corresponded to 60% of that for soybean oil meal. With increasing age the ability of pigs to utilize the fungus increased. The limited nutritive value for monogastric animals is most certainly caused by the cell‐wall structure of S. pulverulentum with poor digestibility of the carbohydrates. The experiment with sheep showed more satisfactory results than with monogastric species, with digestibility of crude protein of 82% and a content of metabolizable energy of 70% of soybean oil meal.