Introduction.

Solid state fermentation is a biotechnology that allows to improve nutritional quality of forages and agricultural by-products in order to be used in ruminant feeding.

Objective.

To determine the effect of solid state fermentation process on fermentation indicators (temperature and pH) and chemical composition of taiwan grass (Pennisetum purpureum), black forage sorghum (Sorghum almum) and pineapple (Ananas comosus) peel.

Materials and methods.

A completely randomized design with 3 substrates: taiwan grass, black forage sorghum and pineapple peel with 4 repetitions was used. 1.0 m2 frames, made with concrete blocks; were used, 490 kg of each substrate were mixed with 5% molasses, 1.5% urea, 0.7% ammonium sulfate, and 0.5% mineral mixture. They were deposited in the frames and the fermentation process was carried out on a disinfected concrete floor provided with shade. Material in the frames was turned every 6 hours for 36 hours while the fermentation process lasted.

Results

. In relation to temperature, significant statistical differences (p<0.05) were found between substrates for the different fermentation times. At 0 hours, taiwan grass had the highest temperature and at 24 hours of fermentation, pineapple peel reached the peak with a temperature of 42.5°C. Considering pH, significant differences (p<0.05) were found for the different subtrates at different hours of fermentation, and the values ranged from 4.28 to 7.71. Regarding crude protein concentration, significant differences (p<0.05) were found for pineapple peel, which went from 40.48% at 0 h to 43.40% at 24 h and 33.43% at 36 h of fermentation. No significant differences (p>0.05) were found for cell wall components during the fermentation process.

Conclusions.

Solid state fermentation is a biotechnological process that allowed to detemine its effect on fermentation parameters of 2 forage species and pineapple peel, and also improved crude protein concentration in pineapple peel after 24 h of fermentation.