Abstract

Background: The focus of this study was the production of a multi-enzyme complex (MC) (xylanase, amylase and cellulase) originating from the fungus Trichoderma harzianum (ALL 42 strain), specific for corn-soybean meal-based substrates, and its subsequent use in the diet of broiler chicks.

Methods: Spores of T. harzianum were inoculated in TLE medium containing 0.5% of corn-soybeanbased starter feeds for broiler chicks. After 48 h incubation at 28°C the supernatant was collected and used as source of enzymes. Activities of xylanase, amylase and cellulose were determined and the enzymes were partially characterized. 480 chicks were fed diets supplemented with this MC. These were male, Cobb, with an average starting weight of 50 g, maintained from 1 to 21 days in batteries. The treatments consisted of diets within pre-starter (from 1 to 7 days) and starter (from 8 to 21 days) phases. Food and water availability was unlimited during both experimental periods. Chick weight gain, feed intake, nitrogen intake, nitrogen in excreta, nitrogen balance, nitrogen digestibility and nitrogen retention were determined.

Results: The peak in enzyme production was established within 48 hours of culture; the zones of optimal pH were between 2.5-7.5 and optimal temperature was between 40-55°C. The enzymes presented a wide range of thermostability and were highly stable at optimal pH. Significant effects were not observed (P<0.05) regarding performance. There was a significant effect (P>0.05) with higher intake (39.42 g), balance (28.30 g) and retention (45.98) of nitrogen in the pre-starter phase.

Conclusion: MC enzymes produced by T. harzianum have potentially application in the development of broiler feeds, since are stable across wide pH and temperature ranges. MC enzymes have not provided performance improvement in the tested birds, but have improved the nitrogen metabolism in the prestarter phase.

Keywords: Fungus, exogenous enzymes, amylase, cellulase, xylanase, broiler chicks.

Graphical Abstract