Effect of fungal fermentation on proximate composition and in vitro performance of agrowastes used in animal feed
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Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Ife Journal of Science
Abstract
Large quantities of agricultural wastes generated annually from the processing of agricultural produce are
disposed of indiscriminately in the environment, thus contributing to environmental pollution. Value addition to
cassava (Manihot esculenta Crantz) peels, and a mixture of yam (Dioscorea spp.) and plantain (Musa paradisiaca) peels, which accumulate during manual peeling will help reduce this environmental impact in addition to being a source of income. The effects of fungal fermentation on their proximate composition and suitability for use as enriched animal feed were thus investigated in this study. Cassava peel and yam-plantain peel mixture were each fermented with Aspergillus niger and Trichoderma spp. at 32 C at moisture content of 52% and 60% respectively for a week and the potential of the biomass was investigated in feeding trials of Wistar rats over a four-week period. After sacrifice, their sera and vital organs were analysed for key enzymes and metabolic products. It was observed that Aspergillus niger-fermented cassava peel (FCP) was the best treatment with increased protein content (from 6.73% to 19.3%) due to microbial biomass. While the carbohydrate content decreased following fermentation, the calorific value remained similar to that of the raw peel. No mortality was recorded in the experimental rats fed the FCP and standard commercial feed (CF) while 100% mortality was then observed by the 4 week in the control group fed unfermented cassava peel (UCP). Organ-body weight ratio and some biochemical parameters e.g. cholesterol, high density lipoprotein (HDL), urea of FCP-fed rats were similar to those of the CF group. Lower amounts of some markers e.g. aspartate transaminase (ALP) and alanine transaminase (AST) were observed relative to UCP group. This research demonstrates the potential of microbially-detoxified food waste to replace commercial feed as a cheap alternative with minimal undesirable physiological effects in the animal models.
Description
Solid state fermentation of cassava peels with Aspergillus niger for seven days resulted in improved nutritional profile of the CP which is an abundant agro-waste in Nigeria, suggesting it could be used as a low-cost commercially produced animal feed. A bioassay using Wistar rats demonstrated the effects of fermentation on cassava peel in a living system. Most of the biomarkers showed that fermentation significantly decreased the toxicological effect and improved the tolerance of this otherwise toxic agro-waste. This work thus shows that enriching waste cassava peels by A. niger fermentation could potentially generate increased value for the cassava value-chain while also ameliorating the environmental pollution caused by the indiscriminate disposal of the cassava peels. Subject to further investigations to confirm its effects on the filtering capacity of the kidney and develop mitigation strategies if found necessary, Aspergillus niger-fermented cassava peels are thus recommended for use as a protein-enriched carbohydrate source for various animal feeds.
Keywords
Fungal Fermentation;, Wistar Rats, Plantain Peel, Aspergillus niger, Yam Peel, Food Wastes
Citation
Ahmed El-Imam, A. M., Sulaiman, F. A., Abdulganiyu, A., Inaolaji, S.T., Sanusi, M. (2019) Effect of fungal fermentation on proximate composition and in vitro performance of agrowastes used in animal feed. Ife Journal of Science vol. 21, no. 3. Pages 1 -11.