The Regulatory Mechanism of Feeding a Diet High in Rice Grain on the Growth and microRNA Expression Profiles of the Spleen, Taking Goats as an Artiodactyl Model

Several researchers have testified that feeding with diets high in rice grain induces subacute ruminal acidosis and increases the risk of gastrointestinal inflammation. However, whether diets high in rice grain affect spleen growth and related molecular events remains unknown. Therefore, the present study was conducted to investigate the effects of feeding a high-concentrate (HC) diet based on rice on the growth and microRNA expression profiles in goat spleen. Sixteen Liuyang black goats were used as an artiodactyl model and fed an HC diet for five weeks. Visceral organ weight, LPS (lipopolysaccharide) concentration in the liver and spleen, and microRNA expression were analyzed. The results showed that feeding an HC diet increased the heart and spleen indexes and decreased the liver LPS concentration (p < 0.05). In total, 596 microRNAs were identified, and twenty-one of them were differentially expressed in the spleens of goats fed with the HC diet. Specifically, several microRNAs (miR-107, miR-512, miR-51b, miR-191, miR-296, miR-326, miR-6123 and miR-433) were upregulated. Meanwhile, miR-30b, miR-30d, miR-1468, miR-502a, miR-145, miR-139, miR-2284f, miR-101 and miR-92a were downregulated. Additionally, their target gene CPPED1, CDK6, CCNT1 and CASP7 expressions were inhibited (p < 0.05). These results indicated that the HC diet promoted the growth of the heart and spleen. The HC diet also regulated the expression of miR-326, miR-512-3p, miR-30b, miR-30d, miR-502a and their target genes (CPPED1, CDK6 and CCNT1) related to the enhancement of splenocyte proliferation. The HC diet also modulated the expression of miR-15b-5p, miR-1468 and miR-92a, related to the suppression of splenocyte apoptosis.

Effects of Subacute Ruminal Acidosis (SARA) on Epidemiological and Clinicopathological Parameters of Dairy Cattle

Background: Subacute ruminal acidosis (SARA) is one of the most important metabolic disease of dairy cattle which decrease milk production, dry matter intake, productivity and increase culling rate and even cause death.Methods: In this study the epidemiological status of SARA namely age, breed, stage of lactation, lactation number, general health condition, body condition score, daily milk production, milk fat content and biochemical alteration were investigated.Result: Out of 100 cows examined 20 were found to be positive for SARA and the mean age of dairy cows suffering from SARA was found to be 6.53 ±0.68 years. The prevalence of SARA was 70 and 30 per cent in Jersey and HF breed of cows respectively and was high in mid lactation and the lactation number ranged from 2 to 6. 65 per cent. SARA affected cows were in poor body condition score, milk production and milk fat content was significantly low (P≤ 0.05). The mean GGT (Gamma Glutamyl Transferase) and AST (Asparate aminotransferase) values were significantly increased in SARA affected dairy cows. SARA seems to be a common problem in dairy cattle and it has to be considered when dealing with herd level problems like low milk fat, low milk production, poor body condition and appropriate management measures should be implemented to prevent it.

Liver transcriptome response to periparturient hormonal and metabolic changes depends on the postpartum occurrence of subacute ruminal acidosis in Holstein cows

We investigated changes in rumen fermentation, peripheral blood metabolites and hormones, and hepatic transcriptomic dynamics in Holstein cows with and those without subacute ruminal acidosis (SARA) during the periparturient period. Sixteen multiparous Holstein cows were categorized in the SARA (n-=-8) or non-SARA (n-=-8) groups depending on whether they developed SARA during the 2 weeks after parturition. Reticulo-ruminal pH was measured continuously throughout the study. Rumen fluid, blood, and liver tissue samples were collected at 3 weeks prepartum and 2 and 6 weeks postpartum, with an additional blood sample collected at 0 and 4 weeks postpartum. The 1-h mean pH was depressed postpartum in both groups, whereas depression was more severe in the SARA group simultaneously with significantly longer duration of time (for pH <5.6 and 5.8). Significant expression of differentially expressed genes in liver tissue (DEGs; false discovery rate corrected P-<-0.1) were identified only in the non-SARA group, and were further analyzed by Ingenuity Pathway Analysis software. Among the top expressed DEGs, the hepatic genes encoding lipid and cholesterol secretion (APOA1, APOA4, and G0S2) and gluconeogenesis (PC, G6PC, and PCK1) were upregulated postpartum. In silico analysis revealed the significant postpartum activation of upstream regulators, such as INSR, PPARG, and PPARGC1A. These results suggested that hepatic transcriptomic responsiveness to postpartum metabolic load and hormones were likely discouraged in cows with SARA when compared to the significant activation of genes and signaling pathways for adequate metabolic adaption to postpartum high-grain diet feeding in Holstein cows without SARA.

Real-time monitoring of ruminal microbiota reveals their roles in dairy goats during subacute ruminal acidosis

Ruminal microbiota changes frequently with high grain diets and the occurrence of subacute ruminal acidosis (SARA). A grain-induced goat model of SARA, with durations of a significant decrease in the rumen pH value to less than 5.6 and an increase in the rumen lipopolysaccharides concentration, is constructed for real-time monitoring of bacteria alteration. Using 16 S rRNA gene sequencing, significant bacterial differences between goats from the SARA and healthy groups are identified at every hour for six continuous hours after feeding. Moreover, 29 common differential genera between two groups over 6 h after feeding are all related to the altered pH and lipopolysaccharides. Transplanting the microbiota from donor goats with SARA could induce colonic inflammation in antibiotic-pretreated mice. Overall, significant differences in the bacterial community and rumen fermentation pattern between the healthy and SARA dairy goats are real-time monitored, and then tested using ruminal microbe transplantation to antibiotic-treated mice.