Abstract

Partially purified amylase was extracted from the culture medium of Rhizopus sp. grown in potato dextrose broth for 48 h at room temperature by precipitation with 96.9% ethanol. The enzyme was used to hydrolyze sorghum starch. The hydrolyzed product was afterwards formulated into rat feed, which was fed to albino rats for a period of thirty days. The average daily body weight of the albino rats fed with hydrolyzed formulated feed on the 30th day of the experiment was 131 g while the values recorded for the groups fed with unhydrolyzed and commercial feed were 120 and 97.4 grams respectively. The hematological analysis revealed that the packed cell volume (PCV), Hemoglobin (Hb), red blood cells (RBC), mean cell hemoglobin concentration (MCHC) of the group fed with hydrolyzed formulated feed of 51.8%, 16.9 g/dl, 8.7 × 10⁵ µl^-1 and 32.7%, respectively, were higher than the experimental animals fed with commercial feed with values of 44.2%, 14.4 g/dl, 7.7 × 10⁵ µl^-1 and 32.3%, respectively. The histopathological results shows that there were no lesion present in both the liver and the kidney of the albino rats fed with commercial feeds while lesions were observed in both the liver of the albino rats fed with hydrolyzed formulated feed and unhydrolyzed formulated feed.

Key words: a-Amylase, Rhizopus sp., Sorghum bicolor starch, hydrolysis, feed formulation, biological studies, albino rats.