KINETICS OF GAS PRODUCTION AND In vitro FERMENTATIVE CHARACTERISTICS OF THE SUBSTITUTION OF CANE MOLASSES FOR MANGO PULP IN THE ELABORATION OF NUTRITIONAL BLOCKS.

Abstract

Nutritional blocks (NB) are a supplement strategy for ruminants, and regional food ingredients such as mango (Mangifera indica L.) are included in their preparation. Due to its rapidly fermentable sugars, mango pulp (MP) may be used to substitute sugar cane molasses in the elaboration of NB. The objective of the present experiment was to evaluate the kinetic of gas production in vitro and the fermentative characteristics of the partial substitution of sugar cane molasses (Saccharum officinarum L.) with MP in the elaboration of NB. The experimental design was completely randomized and the treatments were MP0, MP10, MP20 and MP30, which was the level of substitution of molasses with MP. The variables determined in the sample of each treatment were: dry matter (DM), crude protein, ash, neutral detergent fiber (NDF) and acid detergent fiber (ADF). The biodigesters with 0.5 g of sample from each treatment and 50 mL of culture medium were maintained at 39 °C for 72 h. The variables calculated in the biodigesters were: maximum gas volume (Vf ), gas production rate (S), time lag (l), production of total gases and methane (CH4 ), volatile fatty acids (VFA), degradation of dry matter (DEGDM) and of NDF (DEGNDF) at 72 h. The MP0 produced Vf , of total gases and higher DEGDM and degradation of NDF (DEGNDF) at 72 h. The MP0 produced Vf , of total gases and highest DEGDM (p£0.05). MP0 and MP10 presented higher S and lower l (p£0.05). There were no differences among treatments (p>0.05) for DEGNDF, CH4 and VFA. The partial substitution of mango pulp for sugar cane molasses in nutritional blocks decreased the maximum volume of gas produced, degradation of dry matter, total gases and increased colonization time.