Effect of different glucogenic to lipogenic nutrient ratios on rumen fermentation and bacterial community in vitro

High deoxynivalenol and ergot alkaloid levels in wheat grain: effects on growth performance, carcass traits, rumen fermentation, and blood parameters of feedlot cattle

This study was designed to assess the impacts of a mixture of deoxynivalenol (DON) and ergot alkaloids (EAs) on growth performance, rumen function, blood parameters, and carcass traits of feedlot cattle. Forty steers (450 ± 6.0 kg) were stratified by weight and randomly allocated to 1 of 4 treatments; control-low (CON-L), control-high (CON-H) which contained low or high wheat screenings that lacked mycotoxins at the same level as the mycotoxin-low (MYC-L; 5.0 mg/kg DON, 2.1 mg/kg EA), and mycotoxin-high (MYC-H: 10 mg/kg DON, 4.2 mg/kg EA) diets that included wheat screening with mycotoxins. Steers were housed in individual pens for a 112-day finishing trial. Intake was 24.8% lower (P < 0.001) for MYC steers compared to CON steers. As a result, average daily gains of MYC steers were 42.1% lower (P < 0.001) than CON steers. Gain to feed ratio was also lower (P < 0.001) for MYC steers compared to CON steers. Platelets, alanine aminotransferase, globulins, and blood urea nitrogen were lower (P ≤ 0.008), and lymphocytes, glutathione peroxidase activity (GPx), and interleukin-10 (IL-10) were elevated (P ≤ 0.002) in MYC steers compared to CON steers. Hot carcass weights and backfat thickness were reduced (P < 0.001) in MYC steers, resulting in leaner (P < 0.001) carcasses and higher (P < 0.007) meat yield compared to CON steers. Results suggest that a mixture of DON and EAs negatively impacted health, performance, and carcass traits of feedlot steers, with the majority of this response likely attributable to EAs. However, more research is needed to distinguish the relative contribution of each mycotoxin to the specific responses observed.

Dietary β-hydroxybutyric acid improves the growth performance of young ruminants based on rumen microbiota and volatile fatty acid biosynthesis

Introduction

The ketone body β-hydroxybutyric acid (BHB) plays critical roles in cellular proliferation and metabolic fuel utilization; however, its effects on the rumen microbiota remain unknown.

Methods

Here, three doses of BHB (low, medium, and high) were supplemented to early-weaned goat kids.

Results

Compared with controls, the beneficial effects of BHB on growth and rumen development were observed in goats at 90 days of age (d). The low dose of dietary BHB increased the concentration of rumen acetate, propionate, and butyrate on d90. The sequencing results of the rumen microbiota revealed marked shifts in rumen microbial community structure after early-weaned goat kids consumed BHB for 2 months. The signature bacterial ASVs for each treatment were identified and were the main drivers contributing to microbial interactions in the rumen. The bacteria associated with rumen weight were also correlated with body weight. Some classified bacterial signatures, including Prevotella, Olsenella umbonate, and Roseburia faecis, were related to rumen volatile fatty acids and host development.

Conclusion

Overall, dietary BHB altered rumen microbiota and environments in young goats, which contributed to rumen development and growth.

Effects of Phlorotannins from Sargassum on In Vitro Rumen Fermentation, Microbiota and Fatty Acid Profile

The fatty acid profiles of ruminant-derived products are closely associated with human health. Ruminal microbiota play a vital role in modulating rumen biohydrogenation (BH). The aim of this study was to assess the influence of dietary supplementation with phlorotannins (PTs) extracted from Sargassum on rumen fermentation, fatty acid composition and bacterial communities by an in vitro culture study. The inclusion of PTs in the diet increased dry matter digestibility and gas production, and reduced ammonia-N concentration and pH. PT extract inhibited rumen BH, increasing the content of trans-9 C18:1, cis-9 C18:1, trans-9 and trans-12 C18:2 and reducing C18:0 concentration. 16S rRNA sequencing revealed that PTs caused an obvious change in rumen bacterial communities. The presence of Prevotella decreased while carbohydrate-utilizing bacteria such as Prevotellaceae_UCG-001, Ruminococcus, Selenomonas, Ruminobacter and Fibrobacter increased. Correlation analysis between rumen FA composition and the bacterial microbiome revealed that Prevotellaceae_UCG-001, Anaerovorax, Ruminococcus, Ruminobacter, Fibrobacter, Lachnospiraceae_AC2044_group and Clostridia_UCG-014 might have been involved in the BH process. In conclusion, the results suggest that the inclusion of PTs in the diet improved rumen fermentation and FA composition through modulating the rumen bacterial community.

Shift of Feeding Strategies from Grazing to Different Forage Feeds Reshapes the Rumen Microbiota To Improve the Ability of Tibetan Sheep (Ovis aries) To Adapt to the Cold Season

The dynamics of ruminant-rumen microbiome symbiosis associated with feeding strategies in the cold season were examined. Twelve pure-grazing adult Tibetan sheep (Ovis aries) (18 months old; body weight, 40 ± 0.23 kg) were transferred from natural pasture to two indoor feedlots and fed either a native-pasture diet (NPF group) or an oat hay diet (OHF group) (n = 6 per treatment), and then the flexibility of rumen microbiomes to adapt to these compositionally different feeding strategies was examined. Principal-coordinate analysis and similarity analysis indicated that the rumen bacterial composition correlated with altered feeding strategies. Microbial diversity was higher in the grazing group than in those fed with native pasture and an oat hay diet (P < 0.05). The dominant microbial phyla were Bacteroidetes and Firmicutes, and the core bacterial taxa comprised mostly (42.49% of shared operational taxonomic units [OTUs]) Ruminococcaceae (408 taxa), Lachnospiraceae (333 taxa), and Prevotellaceae (195 taxa), which were relatively stable across different treatments. Greater relative abundances of Tenericutes at the phylum level, Pseudomonadales at the order level, Mollicutes at the class level, and Pseudomonas at the genus level were observed in a grazing period than in the other two treatments (NPF and OHF) (P < 0.05). In the OHF group, due to the high nutritional quality of the forage, Tibetan sheep can produce high concentrations of short-chain fatty acids (SCFAs) and NH3-N by increasing the relative abundances of key bacteria in the rumen, such as Lentisphaerae, Negativicutes, Selenomonadales, Veillonellaceae, Ruminococcus 2, Quinella, Bacteroidales RF16 group, and Prevotella 1, to aid in nutrients degradation and energy utilization. The levels of beneficial bacteria were increased by the oat hay diet; these microbiotas are likely to help improve and maintain host health and metabolic ability in Tibetan sheep to adapt to cold environments. The rumen fermentation parameters were significantly influenced by feeding strategy in the cold season (P < 0.05). Overall, the results of this study demonstrate the strong effect of feeding strategies on the rumen microbiota of Tibetan sheep, which provided a new idea for the nutrition regulation of Tibetan sheep grazing in the cold season on the Qinghai-Tibetan Plateau. IMPORTANCE During the cold season, like other high-altitude mammals, Tibetan sheep have to adapt their physiological and nutritional strategies, as well as the structure and function of their rumen microbial community, to the seasonal variation of lower food availability and quality. This study focused on the changes and adaptability in the rumen microbiota of Tibetan sheep when they adapted from grazing to a high-efficiency feeding strategy during the cold season by analyzing the rumen microbiota of Tibetan sheep raised under the different management systems, and it shows the linkages among the rumen core and pan-bacteriomes, nutrient utilization, and rumen short-chain fatty acids. The findings from this study suggest that the feeding strategies potentially contribute to variations in the pan-rumen bacteriome, together with the core bacteriome. Fundamental knowledge on the rumen microbiomes and their roles in nutrient utilization furthers our understanding of how rumen microbial adaptation to harsh environments may function in hosts. The facts obtained from the present trial clarified the possible mechanisms of the positive effects of feeding strategy on nutrient utilization and rumen fermentation in harsh environments.

Glucogenic and lipogenic diets affect in vitro ruminal microbiota and metabolites differently

This study was conducted to evaluate the effects of two glucogenic diets (C: ground corn and corn silage; S: steam-flaked corn and corn silage) and a lipogenic diet (L: sugar beet pulp and alfalfa silage) on the ruminal bacterial and archaeal structures, the metabolomic products, and gas production after 48 h in vitro fermentation with rumen fluid of dairy cows. Compared to the C and S diets, the L dietary treatment leaded to a lower dry matter digestibility (DMD), lower propionate production and ammonia-nitrogen concentration. The two glucogenic diets performed worse in controlling methane and lactic acid production compared to the L diet. The S diet produced the greatest cumulative gas volume at any time points during incubation compared to the C and L diet. The metabolomics analysis revealed that the lipid digestion especially the fatty acid metabolism was improved, but the amino acid digestion was weakened in the L treatment than in other treatments. Differences in rumen fermentation characteristics were associated with (or resulting from) changes in the relative abundance of bacterial and archaeal genera. The rumen fluid fermented with L diet had a significantly higher number of cellulolytic bacteria, including the genera of Ruminococcus, Butyrivibrio, Eubacterium, Lachnospira, unclassified Lachnospiraceae, and unclassified Ruminococcaceae. The relative abundances of amylolytic bacteria genera including Selenomonas_1, Ruminobacter, and Succinivibrionaceae_UCG-002 were higher in samples for diets C and S. The results indicated that the two glucogenic diets leaded to a higher relative abundance of bacteria which functions in succinate pathway resulting in a higher propionate production. The steam-flaked corn diet had a higher gas production and lower level of metabolites in fatty acids and amino acids. Most highly abundant bacteria were observed to be not sensitive to dietary alterations of starch and fiber, except for several amylolytic bacteria and cellulolytic bacteria. These finding offered new insights on the digesting preference of ruminal bacteria, which can assist to improve the rumen functioning.

Possibility of Using By-Products with High NDF Content to Alter the Fecal Short Chain Fatty Acid Profiles, Bacterial Community, and Digestibility of Lactating Dairy Cows

This study aimed to investigate whether agricultural by-products with a high NDF content and small-particle-size substitute for forage could cause hindgut acidosis and dysbacteriosis in lactating dairy cows. We investigated the impact of soybean hull and beet pulp on the fecal fermentation, bacterial community, and digestibility of cows. Sixteen lactating Holstein cows were treated as follows (% of dry matter (DM)): amount of by-product added was 0 (control, CON), 1.67% (low by-products, LB), 3.33% (medium by-products, MB), and 5% (high by-products, HB). The results showed the fecal pH of cows to be 7.23–7.29, implying no hindgut acidosis. With increased inclusion of by-products in the diets, the proportion of fecal propionate; relative abundance of the phylum Bacteroidetes, the family Lachnospiraceae, and genera unclassified_f_Lachnospiraceae, Acetitomaculum, and Prevotella; and the DM and NDF digestibility of cows all increased linearly. Meanwhile, the fecal genera Turicibacter and Clostridium_sensu_stricto_1 decreased linearly. By-products promoted the abundance of fecal bacteria genes related to energy metabolism, glycolysis/gluconeogenesis, and propanoate metabolism; and correlations between fecal short chain fatty acids, digestibility, and the bacteria genera were seen. Overall, our study suggested that adding 5% by-products could be a viable dietary formulation strategy that promotes digestibility and makes positive changes in hindgut fermentation and bacteria.