Search Results (4)

Direct-fed microbials (DFMs) have shown the potential to improve livestock performance and overall health. Extensive research has been conducted to identify new DFMs and understand their mechanisms of action in the gut. Bacillus species are multifunctional spore-forming bacteria that exhibit resilience to harsh conditions, making them ideal candidates for applications in the feed industry and livestock production. This study investigates the mode of action of B. licheniformis and B. subtilis in the rumen using diverse in vitro techniques. Our results revealed that both strains germinated and grew in sterile rumen and intestinal contents from dairy cows and bulls. Gas composition analysis of in vitro cultures in a medium containing 40% rumen fluid demonstrated that germination of B. licheniformis and B. subtilis strains reduced oxygen levels, promoting an anaerobic environment favorable to rumen microbes. Enzymatic activity assays showed that B. licheniformis released sugars from complex substrates and purified polysaccharides in filtered rumen content. Additionally, the combination of B. licheniformis and B. subtilis survived and grew in the presence of a commercial monensin dose in rumen fluid media. The effects of B. licheniformis and B. subtilis on rumen fermentation activity and microbiota were studied using an in vitro batch fermentation assay. In fermenters that received a combination of B. licheniformis and B. subtilis, less CO₂ was produced while dry matter degradation and CH₄ production was comparable to the control condition, indicating better efficiency of dry matter utilization by the microbiota. The investigation of microbiota composition between supplemented and control fermenters showed no significant effect on alpha and beta diversity. However, the differential analysis highlighted changes in several taxa between the two conditions. Altogether, our data suggests that the administration of these strains of Bacillus could have a beneficial impact on rumen function, and consequently, on health and performance of ruminants. Full article

In this study, we investigated the variations in production performance, health status, and gut microbiota of meat rabbits raised in the semi-confined barn during summer and winter. Compared to summer, rabbits reared in winter possessed significantly higher slaughter weight and carcass weight. Rabbits fed in the summer were more vulnerable to different stressors, which led to increased protein levels of HSP90, IL-1α, IL-1β, IL-2, and concentrations of MDA, but declined GSH and SOD activities. Additionally, significant differences in gut microbial communities were observed. Compared to the winter, rabbits fed in the summer had significantly lower and higher alpha and beta diversity. Both Firmicutes and Verrucomicrobiota were the dominant phyla, and they accounted for greater proportions in the winter than in the summer. At lower microbial taxa levels, several seasonal differentially enriched microbes were identified, such as Akkermansia muciniphila, the Oscillospiraceae NK4A214 group, the Christensenellaceae R-7 group, Alistipes, and Muribaculaceae. Functional capacities linked to microbial proliferation, nutrient metabolism, and environmental adaptive responses exhibited significantly different abundances between summer and winter. Moreover, strong interactions among different indicators were presented. Based on our findings, we not only proposed several potential strategies to ameliorate the undesirable effects of seasonal changes on the productivity and health of meat rabbits but also underscored the directions for future mechanistic studies of adaptation physiology. Full article

Direct-fed microbial products (DFM) are probiotics that can be used advantageously in ruminant production. The in vitro gas production technique (IVGPT) is a method to simulate rumen fermentation and can be used to measure degradation, gas production, and products of fermentation of such additives. However, inter-laboratory differences have been reported. Therefore, tests using the same material were used to validate laboratory reproducibility. The objective of this study was to assess the effect of adding two DFM formulations on fermentation kinetics, methane (CH₄) production, and feed degradation in two different basal feeds while validating a newly established IVGPT laboratory. Six treatments, with three replicates each, were tested simultaneously at the established IVGPT lab at the University of Copenhagen, and the new IVGPT lab at Chr. Hansen Laboratories. Maize silage (MS) and grass silage (GS) were fermented with and without the following DFM: P1: Ligilactobacillus animalis and Propionibacterium freudenreichii (total 1.5 × 10⁷ CFU/mL), P2: P1 with added Bacillus subtilis and B. licheniformis (total 5.9 × 10⁷ CFU/mL). The DFM were anaerobically incubated in rumen fluid and buffer with freeze-dried silage samples for 48 h. Total gas production (TGP: mL at Standard Temperature and Pressure/gram of organic matter), pH, organic matter degradability (dOM), CH₄concentration (MC) and yield (MY), and volatile fatty acid (VFA) production and profiles were measured after fermentation. No significant differences between the laboratories were detected for any response variables. The dOM of MS (78.3%) was significantly less than GS (81.4%), regardless of the DFM added (P1 and P2). There were no significant differences between the effects of the DFM within the feed type. MS produced significantly more gas than GS after 48 h, but GS with DFM produced significantly more gas at 3 and 9 h and a similar gas volume at 12 h. Both DFM increased TGP significantly in GS at 48 h. There was no difference in total VFA production. However, GS with and without probiotics produced significantly more propionic acid and less butyric acid than MS with and without probiotics. Adding P2 numerically reduced the total methane yield by 4–6% in both MS and GS. The fermentation duration of 48 h, used to determine maximum potential dOM, may give misleading results. This study showed that it is possible to standardize the methodology to achieve reproducibility of IVGPT results. Furthermore, the results suggest that the P2 DFM may have the potential to reduce CH₄ production without affecting organic matter degradation. Full article

The constant increment in the world’s population leads to a parallel increase in the demand for food. This situation gives place the need for urgent development of alternative and sustainable resources to satisfy this nutritional requirement. Human nutrition is currently based on fisheries, which accounts for 50% of the fish production for human consumption, but also on agriculture, livestock, and aquaculture. Among them, aquaculture has been pointed out as a promising source of animal protein that can provide the population with high-quality protein food. This productive model has also gained attention due to its fast development. However, several aquaculture species require considerable amounts of fish protein to reach optimal growth rates, which represents its main drawback. Aquaculture needs to become sustainable using renewable source of nutrients with high contents of proteins to ensure properly fed animals. To achieve this goal, different approaches have been considered. In this sense, single-cell protein (SCP) products are a promising solution to replace fish protein from fishmeal. SCP flours based on microbes or algae biomass can be sustainably obtained. These microorganisms can be cultured by using residues supplied by other industries such as agriculture, food, or urban areas. Hence, the application of SCP for developing innovative fish meal offers a double solution by reducing the management of residues and by providing a sustainable source of proteins to aquaculture. However, the use of SCP as aquaculture feed also has some limitations, such as problems of digestibility, presence of toxins, or difficulty to scale-up the production process. In this work, we review the potential sources of SCP, their respective production processes, and their implementation in circular economy strategies, through the revalorization and exploitation of different residues for aquaculture feeding purposes. The data analyzed show the positive effects of SCP inclusion in diets and point to SCP meals as a sustainable feed system. However, new processes need to be exploited to improve yield. In that direction, the circular economy is a potential alternative to produce SCP at any time of the year and from various cost-free substrates, almost without a negative impact. Full article