Proportions of Concentrate and Corn Silage Rehydrated Ground Grain at Different Storage Times for Better Use of Starch by Lambs

The objective of this study was to evaluate the nutritional and bioeconomic potential of corn silage, rehydrated ground grain corn silage (RCGS), at different storage times associated with proportions of concentrates for better starch utilization by sheep. Forty Dorper-Santa Inês crossbred sheep were used, with an average body weight of 24 kg ± 3.9 kg, and an average age of 60 days. The sheep were confined for 63 days and distributed entirely at random with eight sets of repetitions and five experimental diets: Diet 1: ground corn dry; Diet 2: proportion of 850 g / kg of concentrate + rehydrated ground grain corn silage (RCGS) stored for 45 days; Diet 3: proportion of 650 g / kg of concentrate + RCGS stored for 90 days; Diet 4: RCGS stored for 45 days + 650 g/kg concentrate; Diet 5: RCGS stocked with 90 + 850 g/kg concentrate. As roughage, silage corn whole plant. Starch intake was higher (P<0.05) with the dry ground corn diet, however, digestibility was lower (P<0.05) for most nutrients compared to the RCGS diet. A smaller amount of starch was found in the feces of animals that received the RCGS diet. RCGS stored for 45 days and the diet with 650 g/kg of concentrate generates greater net income, increases nutrient intake, it is an alternative during the fluctuation of corn prices.

Metaproteomic responses of in vitro gut microbiomes to resistant starches: the role of resistant starch type and inter-individual variations

Resistant starches (RS) are dietary compounds processed by the gut microbiota into metabolites, such as butyrate, that are beneficial to the host. The production of butyrate by the microbiome appears to be affected by the plant source and type of RS as well as the individual’s microbiota. In this study, we used in vitro culture and metaproteomic methods to explore the consistency and variations in individual microbiome’s functional responses to three types of RS - RS2(Hi Maize 260), RS3(Novelose 330) and RS4(Fibersym RW). Results showed that RS2 and RS3 significantly altered the levels of protein expression in the individual gut microbiomes, while RS4 did not result in significant protein changes. Significantly elevated protein groups were enriched in carbohydrate metabolism and transport functions of families Eubacteriaceae, Lachnospiraceae and Ruminococcaceae. In addition, Bifidobacteriaceae was significantly increased in response to RS3. We also observed taxon-specific enrichments of starch metabolism and pentose phosphate pathways corresponding to this family. Functions related to starch utilization, ABC transporters and pyruvate metabolism pathways were consistently increased in the individual microbiomes in response to RS2 and RS3; in contrast, the downstream butyrate producing pathway response varied. Our study confirm that different types of RS have markedly variable functional effects on the human gut microbiome, and also found considerable inter-individual differences in microbiome pathway responses.

A deletion in theSTA1promoter determines maltotriose and starch utilization inSTA1+Saccharomyces cerevisiaestrains

Diastatic strains ofSaccharomyces cerevisiaeare common contaminants in beer fermentations and are capable of producing an extracellularSTA1-encoded glucoamylase. Recent studies have revealed variable diastatic ability in strains tested positive forSTA1,and here we elucidate genetic determinants behind this variation. We show that poorly diastatic strains have a 1162 bp deletion in the promoter ofSTA1. With CRISPR/Cas9-aided reverse engineering, we show that this deletion greatly decreases the ability to grow in beer and consume dextrin, and the expression ofSTA1. New PCR primers were designed for differentiation of highly and poorly diastatic strains based on the presence of the deletion in theSTA1promoter. In addition, using publically available whole genome sequence data, we show that theSTA1gene is prevalent in among the ‘Beer 2’/’Mosaic Beer’ brewing strains. These strains utilize maltotriose efficiently, but the mechanisms for this have been unknown. By deletingSTA1from a number of highly diastatic strains, we show here that extracellular hydrolysis of maltotriose throughSTA1appears to be the dominant mechanism enabling maltotriose use during wort fermentation inSTA1+strains. The formation and retention ofSTA1seems to be an alternative evolutionary strategy for efficient utilization of sugars present in brewer’s wort. The results of this study allow for the improved reliability of molecular detection methods for diastatic contaminants in beer, and can be exploited for strain development where maltotriose use is desired.

Non-lethal growth inhibition by arresting the starch utilization system of clinically relevant human isolates of Bacteroides dorei

Acarbose elicits potent, non-microbicidal growth inhibition of clinically relevant Bacteroides dorei strains by arresting the starch utilization system.