Downregulation of prostaglandin E2 is involved in hindgut mucosal damage in lactating goats fed a high-concentrate diet

Differential expressions of hypothalamic thermosensitive TRP ion channels may underlie the posthatching ontogeny of brain cooling capacity in broiler chickens

Two trials were performed to evaluate the association of hypothalamic abundances of thermosensitive transient receptor potential (TRP) ion channels with thermoregulation in broiler chickens. In trial 1, temporal changes in body temperatures, and hypothalamic expression patterns of TRP channels and thermoregulatory neurotransmitter concentrations were assessed from 3 to 42 d of age. In trial 2, the same variables were compared at 2 age stages between 2 distinct types of birds with high or low rectal temperatures (HRT or LRT). The core-to-brain temperature difference exhibited a rapid increase after hatching, arriving at a steady state in the fourth week (P < 0.01). The hypothalamus saw a progressive decrease of TRPV4 protein expression through 28 d (P < 0.01), followed by a great increase in the abundance of other channels right up to the end (P < 0.05). Compared to LRT birds, a decline in hypothalamic content of TRPV4 (P < 0.05), together with a bigger core-to-brain temperature difference (P < 0.01), was evident in the HRT counterpart at 33 d. In both trials, the core-to-brain and core-to-surface temperature differences were controlled in a synchronous and coordinated manner. These results allow concluding that developmental changes in the thermal sensitivity of hypothalamic neurons, determined by brain cooling capacity, involve a neuro-genomic mechanism, which regulates the ratio between thermosensitive TRP ion channels to attain a lower proportion of TRPV4 in comparison with other channels.

Impact of quorum sensing signaling molecules in gram-negative bacteria on host cells: current understanding and future perspectives

Quorum sensing is a molecular signaling-based communication mechanism in prokaryotes. In the basic mode, signaling molecules released by certain bacteria are sensed by intracellular receptors or membrane-bound receptors of other members in the community, leading to the collective isogenic signaling molecule synthesis and synchronized activities. This regulation is important for the symbiosis of the bacterium with the host, as well as virulence and biofilm formation. Notably, quorum sensing signaling molecules are not only able to control microbial community behavior but can likewise regulate the physiological status of host cells. Here, we provide a comprehensive review of the importance of quorum sensing signaling molecules in gram-negative bacteria in regulating host cell function and gut health, and suggest possible opportunities for application in combating human and animal diseases by blocking the pathways through which quorum sensing signaling molecules exert their functions.

Microbial community shifts elicit inflammation in the caecal mucosa via the GPR41/43 signalling pathway during subacute ruminal acidosis

Background

Dietary structure in ruminants is closely connected with the composition of gastrointestinal microbiota. Merging study has shown that dietary induced SARA causes the alteration of microbial community in the cecum leading to the local inflammation. However, the mechanisms of cecum inflammation elicited by the shift of microbial flora in ruminants are largely unknown, and whether the development of this inflammation is modified by epigenetic modifications.

Results

Ten multiparous lactating goats were randomly seperated into two groups and received either a low concentrate diet (LC, 40% concentrate, n = 5) or a high concentrate diet (HC, 60% concentrate) to induce subacute ruminal acidosis (SARA). Compared with LC, HC-induced SARA altered the predominant phyla and genera, thereby increasing the concentration of lipopolysaccharide (LPS) and short chain fatty acids (SCFAs). Meanwhile, HC-induced SARA enhanced the mRNA expression of cytokines and chemokines and the expression of mRNA and protein of GPR41, GPR43, p38 and ERK1/2, while HC-induced SARA had no effect on TLR4 and p65. Furthermore, HC-induced SARA decreased the percentage of chromatin compaction and DNA methylation at the area of the promoters of GPR41 and GPR43.

Conclusion

This study indicated that HC diet induced SARA resulted in the alteration in the composition of cecal microbiota. This alteration increased the concentration of LPS, but failing to activate TLR4 signaling pathway due to the tolerance effect of intestinal epithelial cell to certain level of LPS, as well as elevated the concentration of SCFAs, thereby activating GPR41 and GPR43 signaling pathway to produce cytokines and chemokins and cause the cecal inflammation. And epigenetic mechanisms contributed to the development of this inflammation in the lactating goats suffering from SARA.

Electronic supplementary material

The online version of this article (10.1186/s12917-019-2031-5) contains supplementary material, which is available to authorized users.

Microbiome-Metabolome Responses to a High-Grain Diet Associated with the Hind-Gut Health of Goats

Studies on the effect of a high-concentrate (HC) diet on the hindgut microbiota and metabolome of ruminants are rarely reported. We used 454 pyrosequencing of 16S rDNA genes and gas chromatography-mass spectrometry to evaluate the effects of long-term feeding (HL) or short-term (HS) feeding of an HC diet on changes in bacterial microbiota and their metabolites in the hindgut, with Guanzhong goat as a ruminant model. Results indicated that an HC diet decreased bacterial diversity and induced metabolic disorder in the hindgut. The levels of lactate, endotoxin (lipopolysaccharide, LPS), and volatile fatty acid concentrations were higher in the intestinal digesta of the HC goats than in those of the LC goats (P < 0.05). The level of beta-alanine decreased, whereas the levels of stigmasterol and quinic acid decreased in the cecal and colonic digesta of the HC goats. At the genus level, the abundance of Clostridium and Turicibacter was significantly increased in both the colonic and cecal digesta of the HC goats. Several potential relationships between metabolites and several microbial species were revealed in this study. The mRNA expression of the genes functionally associated with nutrients transport, including NHE2, NHE3, MCT1, and MCT4 were significantly downregulated in the colonic mucosa by the HC diet (P < 0.05). The expression levels of the genes related to the inflammatory response, including TLR4, MYD88, TNF-α, and IL-1β were markedly upregulated in the cecal mucosa by the HC diet (P < 0.05). Our results indicate that an HC diet induces microbiota dysbiosis, metabolic disorders, and mucosal damage in the hindgut of goats.