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Compiled by: mushroom, edited by: xiaojunzhu, Jiang shunyao.
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Guide reading
In recent years, the research on the direct relationship between human inflammation and aging and intestinal flora is very common, but there are few reports on dairy cows. In order to understand the changes of intestinal microbial community, inflammatory state and milk production performance in the aging process of dairy cows, the fecal bacterial community, milk composition, inflammatory cytokines, blood routine and rumen microbial community of 180 dairy cows were studied and analyzed.
1. By analyzing the milk composition and daily milk output of dairy cows in different lactation period, the change rule of milk production was evaluated. The results showed that the daily milk output and lactose content of dairy cows in the elderly group decreased significantly, and the number of somatic cells increased significantly.
2. The high-throughput sequencing of 16S rRNA amplification fragment was used to analyze the microbial community and predict its function, and then to study the change rule of rumen and fecal microbial community. The results showed that the fecal microorganisms were mainly composed of prevoridae and trichospirillaceae, and they were abundant in young and middle-aged cows (lefse, LDA & gt; 2). The rumen and fecal microorganisms in the samples of six pastures showed similar changes with age. The abundance of probiotics such as Bacteroides, eubacteria and bifidobacteria in the faeces of the old group was lower (lefse, LDA & gt; 2). The reconstruction of fecal bacterial community showed that compared with the young group, the fermentation pattern of the old group was changed: protein metabolism related function increased, carbohydrate and fat metabolism related function decreased (P & lt; 0.05).
3. The level of cytokines related to inflammation in serum was measured to reveal the progress of inflammation. The level of inflammatory cytokines (IL-10, TNF - α and TGF - β) was significantly increased in the old group (P & lt; 0.001), which indicated that there was chronic inflammation in the old group.
4. Through redundancy analysis and network analysis, the relationship between intestinal flora, inflammation and age was revealed.
This study provides strong evidence for the hypothesis that "by regulating the intestinal microbial community structure to prolong the life span and improve the performance of dairy cows".
Paper ID
The original name: the association between infant and age related changes in the rural and fecal microbiology among lactingholstein costs
A study on the relationship between rumen and fecal microbial community and inflammation and age in Holstein cows during lactation
Journal: front Microbiol
IF：4.259
Time of publication: August 2019
Corresponding author: Wang Yachun
Corresponding author unit: Key Laboratory of animal genetics and breeding, Ministry of education, School of animal science and technology, China Agricultural University, National Engineering Laboratory of animal breeding
experimental design
The blood, feces, milk and 30 rumen fluid from the same pasture were collected from 180 Holstein cows of different ages. Cows were divided into three groups according to lactation period: L1 group (young group, n = 60, the first lactation), L3 group (middle-aged group, n = 60, the third lactation) and L5 group (old group, n = 60, the fifth to ninth lactation, the average was the sixth lactation). Cows in the same ranch use the same total mixed diet, and cows in different ranch use different total mixed diet, which is based on corn silage. All the six pastures belong to Beijing Senlong Animal Husbandry Development Co., Ltd., so their pastures management and breeding mode are similar. There was no significant difference in rectal temperature (mean of two independent measurements in the morning), days of lactation (DIM) and body condition score (th) between the three groups (Table 1). The milk components and milk production, the blood cytokines and blood routine tests, the high-throughput sequencing of 16S rRNA amplification fragments of rumen and fecal microorganisms, and the prediction of their functions and metabolic pathways were carried out, and then the results were statistically analyzed. Finally, redundancy analysis and network analysis are used to explore the internal relationship of the change process.
Table 1 shows the body condition score, rectal temperature and lactation days of the experimental cows.
Result
1. The production performance of dairy cows will be decreased due to the inflammatory cytokines produced by the growth of their age
As shown in Table 2, the concentrations of TNF - α, TGF - β and IL-10 in L5 group were significantly higher than those in L1 group and L3 group (P & lt; 0.001), indicating that there was low level of inflammation in vivo, but there was no statistical difference between L1 group and L3 group. The level of IL-6 in L3 group and L5 group was significantly higher than that in L1 group, and there was no significant difference between L3 group and L5 group. It can be seen that the level of all cytokines in L5 group was significantly higher than that in L1 group (P & lt; 0.05). It was also found that lactose and milk production decreased with age, while somatic cell number and freezing point of milk increased (P & lt; 0.001). Among the three groups, the daily milk output of L5 group was the lowest (P & lt; 0.05), and the level of dry matter and milk protein in milk was also the lowest (average level, but the difference was not significant). The results showed that with the increase of age, milk production performance and physiological function of dairy cows decreased. The number of RBC in L1 group was significantly higher than that in L3 group and L5 group (P & lt; 0.001), and the blood physiological indexes related to RBC size (MCV, MCH) and platelet size (PDW, MPV, P-LCR) were lower than those in L5 group (P & lt; 0.05). As shown in Figure 1, cows with high levels of TNF - α in the blood produced less milk (about 2 kg, P & lt; 0.01). .
Table 2 differences of inflammatory cytokines, production performance and routine blood in three lactation groups
Three lactation groups (L1, L3, L5, corresponding to the 1st, 3rd, 5th lactation) were compared with the general linear model GLM in SAS for TNF - α, TNF - α, IL-6, IL-6, TGF - β, TGF - β and TGF - β; IL-10, IL-10; DMY, milk daily output; lactose, milk lactose; car, milk urea; FPD, milk freezing point; solids, milk dry matter; fat, milk fat; protein, milk protein; SCS, milk somatic cell number; WBC, leukocyte count; w-scr, lymphocyte ratio; w-mcr, monocyte ratio; w-lcr, granulocyte ratio; w-scc, lymphoid cell ratio Cell count; w-mcc, monocyte count; w-lcc, granulocyte count; RBC, RBC count; HGB, hemoglobin; HCT, hematocrit; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin volume; MCHC, mean corpuscular hemoglobin concentration; rdw-cv, coefficient of variation width of RBC distribution; rdw-sd, standard deviation width of RBC distribution; PLT, blood distribution Small plate count; PDW, platelet distribution width; MPV, mean platelet volume; P-LCR, platelet large cell ratio.
Figure 1. The SAS GLM program shows that cows with high levels of TNF - α produce less milk. According to the median level of TNF - α, 180 cows were divided into two groups: TNF - α and low level TNF - α. The daily milk production of the two groups was compared with the general linear model.
2. There are significant differences between the microbial communities of cow feces
The principal component analysis showed that there were significant differences (P & lt; 0.001) between the fecal microbial communities of six pastures (supplementary figure S1A), indicating that there were significant differences between the fecal microbial communities of different pastures. Petal chart shows that 54% of 4745 SOTUS are shared by all pastures, but the abundance will fluctuate obviously between pastures. Some SOTUS only exist in one pastureland.
Figure 2 (A-F) principal component analysis (PCoA) visualized the difference of fecal bacterial community among three lactation groups (L1, L2, L3) of six pastures (F1-F6). In each diagram, each point represents a sample, the distance between the two points is similar to the difference of their bacterial community (Bray Curtis), and the points of different lactation groups are represented by different colors.
Table 3 the differences of bacterial communities among the three lactation groups tested by permanova.
Permanova was used to test the difference of fecal bacterial community in three lactation groups of six pastures. F1-F6 represents 6 pasture groups, L1, L3 and L5 represent 3 lactation groups. All P values are calculated by 1000 permutations. Each pair of values is calculated from 20 samples, while each population p value is calculated from 30 samples in the corresponding pasture.
3. Fecal bacterial community will be rebuilt with age
According to the principal component analysis (Fig. 2), there are significant differences between L1 group and L5 group in the six ranch groups. The composition of bacterial community in L3 group in the three ranch groups is very close to L1 group. It is speculated that the similarity may lie between L1 group and L5 group. As shown in Table 3, the bacterial community centers of L1 and L5 groups were significantly separated (P & lt; 0.05). The results showed that there was significant difference between L1 group and L5 group. Non parametric lefse method was used to analyze the differential bacteria (LDA & gt) between lactation groups; 2) , the experimental results (Fig. 3, 4) show that 18 branches act as biomarkers of L5 group (terrispohector, cellosilicicum, christensenellacear-7, a branch and 8 rumen genera of elusimicrobia), and 11 branches are enriched in L3 group (pygmaiocharacter, tyzzerella 3, coprocccus 3. Clostridium 6, Bacteroides, a branch of Bifidobacterium), 33 branches as biomarkers of L1 group (Vibrio succinate, Eubacterium, defluvitaleaceae ucg-01, 12 Spirillum, 4 rumen and Prevotella). The results showed that the fecal microbial community of Holstein cows was reconstructed with the increase of age.
4. Changes of bacterial function with age
37% (93 pathways) of 249 third level KEGG pathways (sample size less than 90) changed during aging (ANOVA, P & lt; 0.05), and figure 5 shows 42 pathways with the most significant difference (P & lt; 0.005). Three carbohydrate metabolism related pathways (fructose and mannose metabolism, galactose metabolism, fructose and mannose metabolism), two lipid metabolism pathways (phospholipid metabolism and lipid metabolism), two immune related pathways (NOD like receptor signal pathway, antigen processing and presentation) were more abundant in group L1 than in group L3 and group L5; six amino acid metabolism related pathways (cysteine) Methionine metabolism, D-alanine metabolism, D-GLUTAMINE and D-glutamic acid metabolism, glutathione metabolism, glycine, serine and threonine metabolism, phosphate and phosphite metabolism) in group L1 were less than those in group L3 and group L5; in addition, in group L3 and group L5, the biosynthesis activity of ansamycin was lower, while some pathways, such as peroxisome, might produce toxic metabolites There are two ways related to trypanosomiasis (African trypanosomiasis and American trypanosomiasis) which are also very rich (Duncan test, P & lt; 0.05).
Fig. 3 histogram of LDA scores of fecal bacteria in three lactation groups with different abundances. Lefse score can be interpreted as the difference of relative abundance of fecal bacterial community in three lactation groups. As a result, the histogram identifies which branches are statistically and biologically different of all detected branches with rich statistical and biological differences, and can explain the largest difference between the 3 groups. In short, the blue lines represent the most abundant bacteria in the L5 group compared to the other two groups.
Figure 4 fecal bacteria