Biological treatment of crop residues as an option for feed improvement in the tropics: A review

Abstract

In tropical countries, roughages feeds are the major diets of ruminant animals which are poor in quality. Hence, improving the nutritive value of feeds of such kind is vital for best utilization for ultimate goal of increased animal production. Animal feeds and feeding practices can be changed by biological catalysts such as fungi with the objective to improve nutritive value and to reduce environmental waste. Biological treatment of such crop residues using white rot fungi can break the lignocellulose structure, liberating free cellulose and thus enhancing their feeding value. Biologically treated roughages have higher digestibility for most of the nutrients with an increase in crude protein content as compared to untreated material, besides ensuring more fermentable substrates in the rumen. In addition, treatment of low-quality animal feeds with white rot fungi species increases the protein and ash contents with a reduction of its fibrous fraction. Moreover, biological treatment roughages feed increases the feed intake, digestibility and eventually livestock production and reproduction. However, the application of biological treatment of roughages is limited by lack of biological agents such as the typical fungi or its products (enzymes) and knowledge of utilization of such agents. The other setback is reduction of weight of the final substrate after the treatment in which case a dry matter loss of substrate can be as high as 40% in prolonged incubation with the fungus. Moreover, there is lack of know how to use such technology in most of tropical Africa including Ethiopia. This review was then organized to create awareness on utilization of biological treatment as remedy for poor quality of roughages, optimizing mechanisms must be sought.

Effect of chemically and biologically treated rice straw on some productive characteristics of Iraqi buffalo (Bubalus bubalis) calves

“…The moral improvement in the weight increases in the third treatment during the different weeks may be due to the action of the fungus on breaking the bonds linking lignin with cellulose and hemicellulose, which increases the availability of nutrients in the rumen and thus increases the utilization of them by microorganisms and improves the nutritional value of straw and improves Feed conversion efficiency [11]. The result of the biological treatment agrees with a previous result [20], which found an improvement in the daily and total gain and attributed this to the result of the positive effect of the biological treatment of rice straw with T. harzianum on the efficiency of microorganisms and the digestion of organic matter. The reason is due to the action of the cellulase enzyme secreted from this fungus used in the treatment, which led to the decomposition of the plant cell wall of the straw using the carbon contained in glucose as a source of energy, which affected the ability and increases the number of microorganisms in the animal's rumen, which led to an increase in the efficiency of food conversion and an improvement in the laboratories.…”

Pleurotus ostreatus Can Significantly Improve the Nutritive Value of Lignocellulosic Crop Residues

“…Although using novel feeds to provide alternative sources was suggested [13], the potential of such novel feeds will need to be confirmed. However, studies suggest that harnessing agricultural wastes could be a reliable source of cheap feed for increased productivity [14,15]. More so, agricultural by-products have been reported to be abundantly available worldwide [16][17][18].…”

“…Though there are physical and chemical treatments to disrupt carbohydrate-lignin complexes in lignocellulosic crop residues to improve their feeding value [21][22][23], their practical application is limited due to societal and environmental concerns. Additionally, the use of microbial additives to promote digestion, intestinal hygiene, and animal performance was reported to be widely investigated [14] which has resulted in the acceptance of biological treatment as an alternative practical and environmentally friendly approach to enhance the nutritive value of corn stover [14,18].…”

“…Asmare [14] provided extensive information on studies conducted on the biological treatment of crop residues with white rot fungi that yielded positive results. It was reported that biological treatment can break lignocellulose structure to liberate cellulose and improve digestibility and nutrients, thus enhancing the feeding value for increased animal production.…”

“…It was reported that biological treatment can break lignocellulose structure to liberate cellulose and improve digestibility and nutrients, thus enhancing the feeding value for increased animal production. Previous studies have shown that white rot treatment of different crop residues resulted in significant changes in the lignin, neutral detergent fiber (NDF), and acid detergent fiber (ADF) contents with values ranging from lower than 10% and as high as over 70% [7,14,18]. Other authors reported a knowledge gap in the approaches for corn stover treatments to improve digestibility [18,24].…”