Production of hemicellulolytic enzymes through solid substrate fermentation and their application in the production of balanced feed for broilers

Abstract

AGROINDUSTRIAL BY-PRODUCTS MAY BE RECYCLED TO REDUCE ENVIRONMENTAL POLLUTION, BY INCORPORATING THEM INTO SOLID SUBSTRATE FERMENTATION (SSF) PROCESSES, WHERE HIGHER VALUE-ADDED PRODUCTS CAN BE OBTAINED. SSF CAN BE CARRIED OUT USING COFFEE WASTES FROM THE SOLUBLE COFFEE INDUSTRY AND CORN COBS AS SUBSTRATES, AND THE FILAMENTOUS FUNGI ASPERGILLUS NIGER GS1, IN ORDER TO PRODUCE ENZYMATIC COMPLEXES WITH HEMICELLULOLYTIC ACTIVITY. TWO ENZYMATIC EXTRACTS WERE OBTAINED, ONE SHOWING HIGH MANNANASE (M) ACTIVITY WHILE THE OTHER SHOWED HIGH XYLANASE (X) ACTIVITY. THESE EXTRACTS WERE CONCENTRATED AND MIXED IN A 1:1 (V/V) RATIO (MX). MX CONTAINED 143.6 U/ML OF MANNANASE, AND 268.7 U/ML OF XYLANASE (1 U = µG OF MANNOSE AND XYLOSE RELEASED PER MIN AT 50°C, FROM LOCUST BEAN GUM AND OAT SPELT XYLAN AS SUBSTRATES, RESPECTIVELY). MX WAS ADDED TO SOYBEAN-SORGHUM-BASED DIETS CONTAINING A METABOLIZABLE ENERGY (ME) AND CRUDE PROTEIN 3% LOWER THAN THE ONE EMPLOYED FOR BROILER CHICKS KEPT IN METABOLIC CHAMBERS, OVER A PERIOD OF 21 DAYS. MX INDUCED A SIGNIFICANT INCREASE (P < 0.05) IN ME (2%) THAT WAS ATTRIBUTED TO PARTIAL HYDROLYSIS OF THE HEMICELLULOSE AVAILABLE IN THE FEED. UNDER COMMERCIAL PRODUCTION CONDITIONS OF BROILER CHICKS (52 DAYS), THE ADDITION OF THE ENZYMATIC EXTRACTS M AND MX TO THE FEED SIGNIFICANTLY IMPROVED (P < 0.05) BODY WEIGHT GAIN (BWG) AND FEED CONVERSION INDEX (FCI), WHEN COMPARED TO THE USE OF A COMMERCIAL ENZYMATIC ADDITIVE. THE M EXTRACT GAVE THE BEST RESULTS, WITH 3132 G OF AVERAGE BWG AND A FCI OF 1.55, WHILE THE CONTROL FEED PRODUCED 2931 G OF BWG AND A FCI OF 1.70.