Aspergillus spp. isolates from bovine rumen can increase the digestibility and degradability of forages

Flávia Oliveira Abrão,Otaviano De Souza Pires Neto,Eduardo Robson Duarte,Anna Carolynne Alvim Duque,Vera Lúcia Dos Santos,Eloísa De Oliveira Simões Simões,Norberto Mário Rodriguez,Moisés Sena Pessoa,Luciana Castro Geraseev

doi:10.33448/rsd-v10i8.17340

Abstract

The bovine production on pastures is a sustainable activity, responsible to generating income and employments in many tropical regions. However, in this system a major obstacle occurs during long dry periods, when the forages show low nutritional quality. In this research we evaluated the in vitro digestibility and degradability of Urochloa decumbens and Cynodon dactylons var Tiffton 85 inoculated with isolates of Aspergillus spp. from the gastrointestinal tract cattle. Four cows with rumen fistula were used as rumen contents donors to determine the in vitro digestibility of dry matter (IVDMD). The treatments were, as follows: control - No fungal inoculum, AT13 – (with Aspergillus terreus isolate), AF69 – (with Asperillus fumigates isolate, MIX (with mix of fungi AT13 and AF69). The analyses were performed in rumen simulator with four replications. The gas production was determined by semi-automatic method for both gas and the mechanics ability to fiber colonization of these fungi isolates were evaluated by scanning electron microscopy. The inclusion of AF69 and MIX promoted significant increase of IVDMD of U. decumbens (41.4 - 42.1%). The dry matter degradability were not influenced by the inoculums types using the by semi-automatic gas production method However, they linearly increased with fermentation time. The two isolates of Aspergillus spp. were able to colonize the U. decumbens fiber showing production of mycelium and reproductive structures in electronic microscopic analyses. The addition these Aspergillus isolates promotes significant increase of IVDMD to U. decumbens, indicating promising potential for development of microbial or probiotic additive to cattle raised on lignified tropical pasture.

Highlights

The remarkable capacity of protein production in ruminants is attributed to the pre-stomach system which houses a complex microbial ecosystem (Kamra, 2005; Liu et al 2020; Russell and Rychlik 2001)
For the four inoculuDM evaluated, U. decumbens IVDMD was significantly lower (35.3 to 42.1%), compared to that observed for Tifton 85 (51.6 to 60.2%)
Treatments with A. fumigatus and fungal mix promoted a significant increase in the IVDMD of U. decumbens (Table 2)

Summary

Introduction

The remarkable capacity of protein production in ruminants is attributed to the pre-stomach system which houses a complex microbial ecosystem (Kamra, 2005; Liu et al 2020; Russell and Rychlik 2001). Fungus species produce synergistically-acting lignocellulolytic enzymes which reduce lignocellulosic residues in nature and to favor the cellulose releasing and other carbohydrates for ruminant feed (Dashtban et al 2001; Russell and Rychlik 20002001). Anaerobic ruminal fungi shows major importance for tropical forage digestion and degradation lignified fibers (Hartinger et al 2021; Paul et al 2004). Facultative anaerobic fungi have notable production of enzymes that facilitate polysaccharide degradation in ruminants. Microbial cultures of Aspergillus oryzae, and the extracts of these fungi may been used as supplements in ruminant diets, improving productivity by 7-8% (Chiou et at., 2002; Sobhy Sallam et al 2020)

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Discussion

Conclusion