| Ruminal epithelium has many important physiological functions, such as the absorption and transport of nutrients, short-chain fatty acid metabolism and urea cycle. Biogenic amines are generated by catalysis of rumen microbial enzymes or enzymes inherent in the feed ingredients. Recent studies have shown that when ruminants are fed high concentrate, the fermentable carbohydrates and degradable protein of of their diets are rapidly degraded to acidic madia, such as VFA and lactic acid, by the role of microorganisms in the rumen, thereby undermining normal acid-base balance in the rumen, ruminal pH dropped and barrier function damaged, finally enabling the abnormal metabolism, which is not easy to permeate the rumen epithelium, into the blood, thus harming the animal body. In addition, the acidic medium produced by the rapid fermentation of the concentrate will change the microbial flora in the rumen; increase the numbers of ruminal biogenic amine-forming microorganism and the content of biogenic amines in the rumen, damage ruminal epithelial barrier, and the content of biogenic amines in the blood. Thereby, we firstly establish the method of determining biogenic amines in the rumen fluid by reverse phase-high performance liquid chromatography, secondly determine the content of biogenic amine in the blood of dairy cow fed high concentrate. On the other hand, we analyze some changes of the dairy cow fed different forage to concentrate ratio diets, such as rumen fermentation parameters, lactation performance, the numbers of ruminal biogenic amine-forming microorganism, feed intake, and the concentration of biogenic amines in the rumen fluid, blood and feces, to study the effect of high concentrate on rumen metabolism, rumen epithelial integrity and animal production performance. Finally, to study the integrity of rumen and cecal epithelium, and the intestinal segments of absorbing biogenic amines, we determined the changes of biogenic amines for goats fed high concentrate diets or a forage diet in the rumen fluid and rumen vein blood, cecal fluid and cecal vein blood. 1Determination of Biogenic Amines in the Rumen Fluid by Reverse Phase-high Performance Liquid ChromatographyThe method of simultaneously detecting the contents of biogenic amines in the goat rumen fluid by RP-HPLC was developed in the present study. Samples were extracted by0.5mol/L hydrochloric acid, and then derived using dansyl chloride. The mobile phase was a gradient elution program with a binarymixture of acetonitrile and0.1mol/L ammonium acetate solution. The flow rate was1mL/min. UV detector’s wavelength was254nm, and column Temperature was30℃. The results showed a good separation of five biogenic amines (tryptamine, putrescine, methylamine, histamine, tyramine) within40min was observed. The average recovery ranged from88.46%～98.49%for all amines, and the RSDs were less than10%. This analysis method developed was used to investigate the effect of the diet with different ration of the forage to concentrate on the changes of the biogenic amines in goat rumen. The results showed that, as compared with the lower concentrate, the tryptamine and histamine concentration was higher, while no significant changes was observed on the putrescine, histamine and tyramine concentration (P<0.05). The methods used in the present study can be used to determine the biogenic amine concentration, and the concentration of the biogenic amines in the rumen fulid of goat was affected by the quantifica of the forage to concentrate in the diet.2Preliminary Investigation of the Biogenic Amine Concentration in Blood of Dairy Cattle in Three Farms in Xigang, Changfeng and Shanghai, and its Correlation with the Milk Yield, Milk Composition and the VFA in FecesThis study was conducted to investigate the concentration of biogenic amine in blood of dairy cow, and its relationship with the milk yield, milk composition and the individual VFA in feces of the dairy cows. The blood from dairy cows were collected from three dairy farms in Xigang (the ratio of the forage to concentration (F:C):35:65), Changfeng ((F:C,3:7), and Shanghai (F:C,4:6). The concentration of biogenic amine from the blood is determined by reverse phase high performance liquid chromatography. The results showed that the high concentrations of tyramine, putrescine, histamine, methylamine and tryptaminethe were detected in the blood of all dairy cows. Correlation analysis showed that significant correlation was not observed between the levels of five amines concentration in tail vein blood and mile yield, milk protein and milk fatty content (P>0.05), the relationship between the volatile fatty acid in feces and the amines was also evaluated, and the results showed that, there was no significant correlation between the VFA composition and biogenic amines concentration (P>0.05). In conclusion, these results suggested that high concentration of biogenic amine were present in the blood in dairy cows from modern dairy farming in China, and it may disrupt the host health.3Effects of Dietary Concentrate on Rumen Fermentation and Biogenic Amines in the Rumen, Peripheral Blood and Feces of Dairy CowsThis study was conducted to investigate if high concentrate diet feeding results in increases of biogenic amine in rumen fluid, peripheral blood and feces, and to determine the effect of high concentrate diet feeding on rumen fermentation characteristics, Change of predominant ruminal biogenic amine-forming microorganism at Oh of sampling and the relationships between ruminal pH and biogenic amines in the rumen fluid, peripheral blood and feces were also evaluated. Four cannulated primiparous (60to140d in milk) Holstein dairy cows were assigned to2diets in a2×2crossover experimental design. The experimental period lasted for21d, with11d of adaptation and10d of measurements. The diets contained (dry matter basis):40%(LowC;control) and70%(HighC) concentrate feeds. Milk samples were collected on d7,8and9of the measurement period to determine milk composition and yield. Rumen fluid samples were collected on d1,4,6and10of the measurement period, and pH, VFA, NH3-N and biogenic amine content were measured. In addition, peripheral blood were collected immediately at15min before feed delivery and at4h and8h after feed delivery on d1,4,6and10of measurement period to measure biogenic amine content. Fecal samples were also taken on d1,4,6and10of measurement period to measure biogenic amine content. Results showed that HighC feeding increased the averages of total volatile fatty acids (125.21to110.83mM), butyrate (14.53to11.29mM), valerate (7.05to4.76mM), total branched-chain VFA (4.93to3.80mM) and decreased the acetate to propionate ratio from3.63to3.29in the rumen (P<0.05). HighC feeding did not significantly increased the daily average of acetate (74.90to70.71mM; P=0.269) and NH3-N (14.465to13.401mM; P=0.315)(P>0.05), and has an increase trend for propionate (23.81to20.29mM;P=0.051)(0.05<P<0.10). The average concentration of tyramine, putrescine, histamine, methylamine and tryptamine were higher in the rumen (147.976vs.99.941μmol/L,39.444vs.17.524μmol/L,161.188vs.46.432μmol/L,31.809vs.28.088μmol/L, and72.251vs.48.767μmol/L, respectively), peripheral blood (8.254vs.2.444μmol/L,9.020vs.1.403μmol/L,7.920vs.2.034μmol/L,15.523vs.12.915μmol/L, and9.247vs.2.705, respectively) and feces (6.166vs.3.871μmol/g,6.707vs.3.387μmol/g,3.740vs.1.564μmol/g,5.830vs.2.978μmol/g,4.733vs.2.077μmol/g, respectively) of HighC group compared with the LowC (P<0.05). Correlation analysis showed that there is a significant negative relationship between ruminal pH and biogenic amines in the rumen fluid, peripheral blood, and between fecal pH and biogenic amine in feces (P<0.05), however, the similar result was not observed in feces. In addition, the relative quantitation of Lactobacillus spp. were affected by the diet fed (P<0.05). In conclusion, results suggest that HighC feeding caused translocation of biogenic amine from the digestive tract and increase of predominant ruminal biogenic amine-forming Lactobacillus spp. Further research is warranted to explore the role of amine and the concrete biogenic amine-forming microorganism in animal physiologic activities, especially in inflammation response during HighC feeding.4The Effect of High Concentrate Feeding on the Changes of Concentration of the Biogenic Amines in Rumen Liquid, Cecum Content, the Blood of Rumen and Cecum Vein in GoatsThis study was conducted to investigate the effect of two diets (10%concentrate diet, LowC;60%concentrate diet, HighC) on the concentration of biogenic amine in the rumen fluid and rumen vein blood, cecal fluid and cecal vein blood, and the correlation between the biogenic concentration of the rumen fluid and rumen vein blood, cecal fluid and cecal vein blood, and the concentration of VFA in the rumen fluid and cecal fluid were also evaluated. Six cannulated goat were assigned to2diets in a randomized block experimental design. Each group contained three goats. The experimental period was lasted for25day. On day23and24of experimental period, the rumen fluid was collected at Oh,2h,4h,6h,8h,10h and12h to measure biogenic amine content, VFA concentration and ruminal pH. On day25, the goats were anesthetized at8:00in the morning, and then slivered the abdomen to collect the rumen fluid, rumen vein blood, cecal fluid and cecal vein blood. The results showed that the concentration of biogenic amine, total VFA, acetate, butyrate, valerate, and total branched-chain VFA were higher in the rumen of HighC group compared with the LowC(P<0.05), however, ruminal pH and the ratio of acetate:propionate were lower(P<0.05). In addition, the concentration of biogenic amine in the rumen fluid, rumen vein blood, cecal fluid and cecal vein blood were higher in the rumen of HighC group compared with the LowC(P<0.05), however, total VFA and valerate in cecum content has a increased trend(P=0.073and P=0.086), and acetate:propionate has a reduced trend(P=0.055). Correlation analysis showed that, except no significant changes was observed between the content of putrescine in the cecal fluid and the content of histamine in the cecal vein blood (P>0.05), there were significant correlations between the biogenic concentration of the rumen fluid and the corresponding amine in rumen vein blood, cecal fluid or cecal vein blood (P<0.05). The results suggested that the high concentrate feeding decreased the rumen and cecum pH, and increased the concentrations of the biogenic amines in the rumen fluid and cecal fluid, and further disrupted the rumen and cecum health. |
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