Biological fungal treatment of olive cake for better utilization in ruminants nutrition in Egypt

Abstract

Background Crop residues and agro-industrial by-products, available in appreciable quantities, can play a significant role in the nutrition of ruminants. The appropriate utilization of by-products in animal nutrition can improve the economy and the efficiency of agricultural, industrial and animal production. The present work investigates the bio-conversion of olive cake (OC), generated by the olive oil industries in Egypt, using locally isolated filamentous fungi in solid state fermentation, so as to upgrade its nutritional values and digestibility for its use as ruminants feed. Methods Seven non-mycotoxin producing fungal strains namely Trichoderma reesei F-418, T. harzianum F-416, T. virdie F-520, T. koningii F-322, Aspergillus oryzae FK-923, A. fumigatus F-993, and A. awamori F-524 were cultured on OC for 7 days at 36°C. Subsequently, the chemical composition and lignocellulolytic enzyme activities of the resultant substrate were determined. Results The most promising result was obtained by A. oryzae FK-923, whereas, an increase in crude protein content ranging from 9.5 % (untreated) to 17.4 % (treated) was detected, while phenols were decreased from 3.1 to 0.92 % and fibers declined from 33 to 22.2 %. A reduction in the values of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were reported. The addition of sugar cane molasses at 2 % showed an increase in crude protein to 18.9 % with a reduction in phenols and fibers to 0.69 and 21.8 %, respectively. Furthermore, the addition of active dry yeast (Saccharomyces cerevisiae) at 1.5 % to the fermentation medium raised the crude protein to 20.2 % (w/ w), while phenols and fibers were declined to 0.55 and 19.2 %, respectively. Conclusions Therefore, the present findings revealed A. oryzae FK-923 to be an efficient organism for lignocellulolytic enzymes production and simultaneous enhancement in crude protein and in vitro digestibility of OC.

Improving the nutritive value of olive pomace by solid state fermentation of Kluyveromyces marxianus with simultaneous production of gallic acid

“…This result is in accordance with that conducted by Uribe et al (2013). Crude fiber ratios of 40, 40.72 and 33% were reported by Ramachandran et al (2007), Brlek et al (2012) and Fadel and El-Ghonemy (2015), respectively. Besides, the crude fat was found to be 13.62% on dry matter basis which was higher than that reported by Uribe et al (2013), (2014a) Uribe et al (2014b).…”

“…Neifar et al (2013) reported ratios of 59, 45, 31, 14.1 and 14.3% for NDF, ADF, ADL, hemicellulose and cellulose, respectively. And, ratios of 62 and 48% were estimated for NDF and ADF, respectively, by Fadel and El-Ghonemy (2015). The variation in the chemical composition of OP reported by different authors can be attributed to the difference in olive variety, cultivation conditions (cultivation soil, geography of cultivation soil and use of pesticides and fertilizers), climatic conditions, harvesting conditions (the degree of ripening, harvesting time and system) and the applied oil extraction process (Doymaz et al 2004;Brlek et al 2012;Uribe et al 2013Uribe et al , 2014aUribe et al , 2014bUribe et al , 2015Christoforou and Fokaides 2016).…”

“…SSF of OP using K. marxianus resulted in an increase in crude protein by 2.74%, changing it from 10.05% for UFOP to 12.79% for FOP. This can be attributed either to the increased biomass or the secretion of enzymes into the fermented medium (Fadel and El-Ghonemy 2015). The increased protein content suggests that the treated substrate is a good protein source for livestock (Neifar et al 2013;Fadel and El-Ghonemy 2015).…”

“…This can be attributed either to the increased biomass or the secretion of enzymes into the fermented medium (Fadel and El-Ghonemy 2015). The increased protein content suggests that the treated substrate is a good protein source for livestock (Neifar et al 2013;Fadel and El-Ghonemy 2015). Also, a decrease of ash and crude fiber content by 0.38 and 8.56%, respectively, was observed after fermentation.…”

“…However, the support must possess enough moisture to sustain microbial growth and metabolism (Pandey 1991). Several researches dealing with SSF of OP using fungal strains have been conducted allowing its use as animal feed additive for both ruminants (cattle, sheep, goats and camels) and poultry (Neifar et al 2013;Fadel and El-Ghonemy 2015).…”