Probiotic levels, chemical composition and fermentative characteristics in the solid state fermentation of paper sludge for ruminant feeding
Sludge from the paper industry could be used for animal feeding when treated with probiotics upon solid state fermentation process. This study assessed the effects of four probiotic levels (PT) on chemical and fermentative characteristics in SSF of the paper sludge (PS) at controlled temperature (30°C) in laboratory scale. The probiotic used in this experiment is a mexican commercial trademark (Prozoot15®) rich in yeasts and lactobacilli, organic acids and vitamins. The tested treatments (T) were: T1 (0% PS), T2 (50 g/kg PS), T3 (100 g/kg PS) and T4 (150 g/kg PS), which were fermented at 0, 24, 48 and 72 h, according to a completely randomized design, in a 4 × 4 factorial arrangement with six repetitions per sampling. All treatments included (g/kg DM) 300 molasses, 15 urea, 20 ammonium sulfate, 9 calcium carbonate and 5 of vitamin and mineral premix, plus the PS which was substituted by the PT at 0, 50, 100 and 150 g/kg DM. The results showed a decrease in pH in all treatments at 24 h; however the lowest pH was at 72 h of fermentation. At 72 h of fermentation, the PT addition in T4 increased crude protein, true protein and yeast counts (P < 0.05), and decreased pH (P < 0.05). In all fermentation time, the PT addition increased ether extract, lactic acid and ammonia nitrogen (P < 0.05) and decreased dry matter, ash, NDF and ADF (P < 0.05). It was concluded that the addition of 150 g/kg of PT in SSF of paper sludge improves crude and true protein, ether extract, lactic acid, and ammonia. This treated byproduct may have a potential use in animal feeding.
Fermentation; Paper Sludge; Yeast;