Effect of different forage-to-concentrate ratios on ruminal bacterial structure and real-time methane production in sheep

Abstract

Emission from ruminants has become one of the largest sources of anthropogenic methane emission in China. The structure of the rumen flora has a significant effect on methane production. To establish a more accurate prediction model for methane production, the rumen flora should be one of the most important parameters. The objective of the present study was to investigate the relationship among changes in rumen flora, nutrient levels, and methane production in sheep fed with the diets of different forage-to-concentration ratios, as well as to screen for significantly different dominant genera. Nine rumen-cannulated hybrid sheep were separated into three groups and fed three diets with forage-to-concentration ratios of 50:50, 70:30, and 90:10. Three proportions of the diets were fed according to a 3 × 3 incomplete Latin square, design during three periods of 15d each. The ruminal fluid was collected for real-time polymerase chain reaction (real-time PCR), high-throughput sequencing and in vitro rumen fermentation in a new real-time fermentation system wit. Twenty-two genera were screened, the abundance of which varied linearly with forage-to-concentration ratios and methane production. In addition, during the 12-hour in vitro fermentation, the appearance of peak concentration was delayed by 26-27min with the different structure of rumen bacteria. The fiber-degrading bacteria were positively correlated with this phenomenon, but starch-degrading and protein-degrading bacteria were negative correlated. These results would facilitate macro-control of rumen microorganisms and better management of diets for improved nutrition in ruminants. In addition, our findings would help in screening bacterial genera that are highly correlated with methane production.

Camelina sativa L. Oil Mitigates Enteric in vitro Methane Production, Modulates Ruminal Fermentation, and Ruminal Bacterial Diversity in Buffaloes

“…Our study revealed higher bacterial species richness both in high-roughage diets and in the lower level of CO as revealed by rarefaction curves. The four phyla, including Bacteroidetes, Firmicutes, Proteobacteria, and Spirochaetes, were detected as major phyla in our study, which is in agreement with earlier reports (13,60). However, change in roughage-to-concentrate ratio favored two phyla Fibrobacteres and Lentisphaerae in the R70:C30 diet and one phylum Synergistetes in R50:C50 diet.…”

Effect Of Dietary Concentrate And Bypass Fat Supplements On In Vitro Rumen Fermentation, Digestibility And Rumen Microbial Population In Buffaloes

“…Similar to the results of this research, concentrate and bypass fat supplementation increased protozoan population in ewes [74]. Conversely, reported by Li et al [45], showed number of total bacteria, methanogens and protozoa were decrease with the in increasing of concentrate ratio in the diet. This nding also might be differing among study because of the variation mixture in the commercialize concentrate provided to the animals.…”

“…The increase in these two cellulolytic bacteria in treatment groups may be due to the impact of the of ingredient contains in concentrate such as corn grain, soybean meal and rice brain, which are known to have enhancer effect on cellulolytic bacteria and eventually improve ber digestibility. With a rise in dietary starch content, the number of cellulolytic bacteria also increased signi cantly in this experiment, suggesting a shift in the carbohydrate fermentation substrate from a non-structural to structural carbohydrate [45]. The lower population of protozoa in this study, with a signi cant increase in Ruminococcus albus is described by the decline of protozoa in the rumen often results in greater proliferation of bacteria and greater passage of bacterial nitrogen N out of the rumen [68].…”

“…compositions within each supplement [11,45]. Bypass fat and concentrate containing high fat and protein were commonly used in ruminant nutrition, especially in cattle and sheep to regulate the activity of the rumen fermentation [10] and rumen microbial population.…”

Cross Inoculation of Rumen Fluid to Improve Dry Matter Disappearance and Its Effect on Bacterial Composition Using an in vitro Batch Culture Model

“…Increases in this genus have been identified previously when providing perennial ryegrass to an in vitro model of rumen fermentation (Elliott et al, 2018) and Pseudobutyrivibrio has also been identified as a native rumen bacterium that holds potential as a rumen probiotic, due to its ability to modulate in vitro fermentation to improve energy yields (Fraga et al, 2014). As Pseudobutyrivibrio has been shown to increase linearly with increasing NDF and ADF in the diet (Li et al, 2019), it is possible that the substrate provided to the model had higher proportions of these than the diet consumed by the animal. In future experiments, it would be of interest to measure enzyme activity as an indicator of changes in bacterial activity.…”