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BACKGROUND A survey on 68 dairy farms was carried out to evaluate the ensiling procedures adopted to store corn silage. Samples from core, lateral and apical zones of the feed-out face of silos were analysed. A principal factor analysis ( PFA) was carried out on the entire database (196 silage samples and 36 variables) and 11 principal factor components ( PCs) were retained and interpreted. RESULTS Ensiling procedures influenced the area exposed to risk of air penetration. Cores had higher dry matter, starch and lactic acid content or lower pH, fibre, propionate and butyrate concentrations than peripheral samples ( P < 0.05). The highest ( P < 0.05) mycophenolic acid and roquefortina C concentrations were detected in lateral samples. Chemical and digestibility variables loaded on two PCs; four PCs were characterized by end-products associated with clostridia, heterolactic, homolactic and aerobic fermentations; two PCs were associated with mycotoxins, whereas three PCs explained ensiling procedures. CONCLUSION The main quality traits of corn silages differed throughout the entire silo face. Minimization of the area exposed to risk of air penetration represents the best strategy to preserve the nutritional value and safety of corn silages. PFA allowed a clusterization of original variables into 11 PCs, appearing able to discriminate well and poorly preserved corn silages. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The objective of this study was to identify and quantify fermentation end-products, detected with chromatographic techniques, that were negatively related to intake of grass silage by cattle. Further, the aim was to verify the intake-depressing effect of these compounds in a feeding trial. A set of twenty-four silages that had been used in a previous study to model variations in intake owing to fermentation quality was reanalysed with liquid and gas chromatography. Known and unknown chromatogram peaks were subjected to a regression analysis to determine which were negatively related to intake. Compounds were identified and quantified using a liquid chromatography-mass spectrometry system; acetic acid (AcA), caproic acid and tryptamine were chosen for verification. Growing steers were offered wilted silage with these three compounds added, separately or as a mixture, in proportions similar to the maximum values detected in the silages of the previous study. Dietary addition of AcA, either separately or mixed with the other two compounds, reduced silage dry matter (DM) intake. However, the reduction in silage DM intake equalled the amount provided by the added substances, so that no differences in total DM intake were observed for any of the dietary treatments. [ABSTRACT FROM AUTHOR]

Abstract: Sixty landrace piglets received either a control diet or a control diet with added carob bean gum (CBG), spray dried porcine plasma (SDPP) or sanguinarine, to test the effects on fermentation end-product profiles along the GI tract. After animals were euthanized digesta samples were obtained from the mid-jejunum, distal ileum, caecum, proximal and distal colon at days d0, d1, d2, d6 and d14 post-weaning. Volatile fatty acid (VFA) concentration in the caecum and proximal colon was larger than that in the distal colon, the ileum and mid-jejunum (P <0.05). At d0 the VFA and NH3 concentration in the ileum, ceacum and proximal colon was higher compared to d1 and d2 (P <0.05). The molar proportions of acetic (AP), propionic (PP) and butyric (BP) acid in the ileum shifted gradually from d0 (87:6:4) to d14 (70:11:16). The proportion of branched chain VFA (BCP) decreased from d1 to d14 in both the caecum (7.1 to 1.3%) and proximal colon (6.9 to 1.2%). At d1 and d2 the additive treatments gave a numerical decrease in VFA compared to control, ammonia levels showed a differential response, and the BCP was numerically higher for the additive treatments compared to control. Results indicated that at the moment of weaning considerable fermentation activity occurs. During the weaning period fermentation in the ileum, caecum and proximal colon shifted from a proteolytic to a carbohydrate type of fermentation. Addition of CBG, sanguinarine and SDPP only resulted in a numerical decrease of fermentation end-product in the caecum and proximal colon during the first days post-weaning. [ABSTRACT FROM AUTHOR]

The great biochemical variability of the raw materials used in horse feeds can induce changes in gastric fermentation, and therefore affect gastric health through the resulting acidity of the bacterial end products. This in vitro trial compared the effect of 6 raw materials (BA: barley; WB: wheat bran; OA: oats; SM: sunflower meal; SB: sugar beet pulp; AL: alfalfa – Table 1) commonly used in horse feeds on gastric bacterial fermentation and buffering capacity. In 3 horses fed a mixture of the 6 raw materials 3h before sampling, gastric chyme was collected via a nasogastric tube and mixed. Bottles containing 1mL of the mixed gastric chymes, 50mL dilution medium and 1.0g of substrate (50% pilled barley + 50% one pilled raw material) were incubated in a shaking water bath at 39°C for 10h. Gas production, volatile fatty acids (VFAs), pH and buffering capacity of the solution (HCl 0.1M volume added to lower pH to 4 in the 50mL solution) were measured every 2h in duplicate. Effect of the substrate, time and their interaction were analyzed using a mixed procedure (SAS). From 4h to 10h incubation, gas production was greater with WB than BA, SM and AL (P < 0.001), reflecting higher bacterial fermentations, probably associated with WB highest soluble sugars content. Higher VFAs concentration were observed with AL than OA and WB at 2h, than BA and SB at 8h, than all other substrates at 10h (P > 0.001). This intense VFAs production with AL suggested environmental conditions more adapted for starch and soluble sugars fermentation, maybe combined with protein fermentation. Little differences were observed between raw materials regarding pH evolution. However, all along the 10h, buffering capacity of the solutions containing AL remained significantly higher than all others (P = 0.002, Table 1). The inclusion of alfalfa in horse feeds could be of interest to delay the decrease in gastric pH associated with HCl secretions and fermentation end products appearance, and to limit the exposure time of gastric mucosa to pH ≤ 4. [ABSTRACT FROM AUTHOR]

• This is the first microbiome study of natural corn grain silage via IlluminaMiSeq. • There is a specific bacterial microbiome for silages linked with quality indicators. • Acetobacter and Lactobacillus were the dominant bacteria after ensiling. • Enterococcus and Clostridium were the dominant bacteria in rehydrated corn. • Plant maturity and storage affected the bacterial community of corn grain silages. This study evaluated changes in the bacterial community in high-moisture and rehydrated corn grain silage, and their correlation with fermentation quality attributes in distinct corn hybrids, the storage period, and kernel maturity at plant harvest. Most silages achieved good fermentation (pH < 4.2). Rehydrated corn had a higher pH across all storage periods evaluated and increased dry matter losses. Leuconostoc and Lactococcus were the dominant genera in fresh material, while Lactobacillus and Acetobacter were prevalent in silages. Clostridium and Enterococcus prevailed in rehydrated corn after 120 days storage, and Clostridium was highly and positively correlated with acetone, butyric acid, and 2,3-butanediol contents. The storage period and kernel maturity were the most important factors responsible for changes in the bacterial community of silages. Results confirmed the existence of a specific bacterial microbiome that was unique for each maturity and storage time. Variations in these factors also affected the fermentation quality through influencing the bacterial community. [ABSTRACT FROM AUTHOR]