Ação combinada de benzoato de sódio e Lactobacillus buchneri sobre a qualidade da silagem de sorgo.

Abstract

The objective was to evaluate the effect of chemical additive and microbial additive on fermentative characteristics, losses, silage quality, growth of microbial populations and the microbiome of sorghum silages. An entirely randomized design (CID) was used in a 4×4 factorial scheme (4 types of silage × 4 opening times), with five repetitions per treatment. The treatments were: without additive (control); additive 1 (silage inoculated with (Lactobacillus buchneri); additive 2 (silage treated with chemical additive: sodium benzoate) and additive 3 (silage inoculated with L. buchneri and combined with chemical additive: sodium benzoate). There was an interaction (P<0.05) between the analyzed factors additive use and silo opening time, for the growth of lactic acid bacteria (BAL) and yeast population in forage sorghum silage. For yeast count the lowest population was observed at the opening of the silo at 60 days with the use of additive 1 (L. buchneri) of 1.67 Log CFU g-1. There was an interaction (P<0.05) for the variable pH between the analyzed factors use of additive and time of silo opening, obtaining higher pH values (3.70) for silages opened at 90 days (P<0.05) with the use of additive 2 (sodium benzoate). The lowest pH value (3.30) was found in the silage inoculated with L. buchneri (additive 1) at 60 days after opening the silo. The MS content (P<0.05) was higher in silage with additive 3 (L. buchneri + sodium benzoate) with a content of 324 g/kg. The FDN of silage with the use of L. buchneri and sodium benzoate (additive 3) had the lowest content of 613.0 g/kg MS in the silage (P<0.05). Regarding the losses due to the ensiling process at 120 days, there was an effect (P<0.05) of the use of additives in sorghum silage for gas loss (PG) of the silages. Additive 2 (sodium benzoate) differed from the other treatments, recording the lowest gas loss. There was an interaction (P<0.05) in the breakdown of aerobic stability of silages for use of additives and time of silo opening, where silages treated with additive 3 (L. buchneri + sodium benzoate) opened at 120 days had longer duration of aerobic stability (87.8 hours). The use of L. buchneri affected the diversity of the bacterial community with a predominance of lactobacilli when the microbial inoculant was used. There was greater bacterial diversity in the control treatment without the use of additives. The effects of the combined action of chemical additives and microbial inoculant (L. buchneri and sodium benzoate) is positive, preserving the chemical composition of silages, reducing gas losses, increasing dry matter content, decreasing fiber content, and satisfactorily improving aerobic stability. In addition, sorghum silages opened at 120 days show greater aerobic stability.