Effect of supplementation of allicin on methanogenesis and ruminal microbial flora in Dorper crossbred ewes

Background： Garlic extracts have been reported to be effective in reducing methanogenesis. Related mechanisms are not well illustrated, however, and most studies have been conducted in vitro. This study investigates the effects of supplementary allicin（AL） in sheep diet on in vivo digestibility, rumen fermentation, and shifts of microbial flora.Methods： Two experiments were conducted using Dorper × thin-tailed Han crossbred ewes. In experiment 1,eighteen ewes（60.0 ± 1.73 kg BW） were randomly assigned for 29 days to either of two dietary treatments： a basal diet or the basal diet supplemented with 2.0 g AL/head？day to investigate supplementary AL on nutrient digestibility and methane emissions. In experiment 2, six ewes（65.2 ± 2.0 kg BW） with ruminal canulas were assigned to the same two dietary treatments as in experiment 1 for 42 days to investigate supplementary AL on ruminal fermentation and microbial flora. The methane emissions were determined using an open-circuit respirometry system and microbial assessment was done by q PCR of 16 S r RNA genes.Results： Supplementary AL increased the apparent digestibility of organic matter（P 〈 0.001）, nitrogen（P = 0.006）,neutral detergent fiber（P 〈 0.001）, and acid detergent fiber（P = 0.002）. Fecal nitrogen output was reduced（P = 0.001）but urinary nitrogen output was unaffected（P = 0.691）, while nitrogen retention（P = 0.077） and nitrogen retention/nitrogen intake（P = 0.077） tended to increase. Supplementary AL decreased methane emissions scaled to metabolic bodyweight by 5.95 %（P = 0.007） and to digestible organic matter intake by 8.36 %（P = 0.009）. Ruminal p H was unaffected（P = 0.601） while ammonia decreased（P = 0.024） and total volatile fatty acids increased（P = 0.024） in response to supplementary AL. Supplementary AL decreased the population of methanogens（P = 0.001） and tended to decrease that of protozoans（P = 0.097）, but increased the populations of F. succinogenes（P 〈 0.001）, R. flavefaciens（P = 0.001）, and B. fibrisolvens（P = 0.001）.Conclusions： Supplementation of AL at 2.0 g/head？day effectively enhanced OM, N, NDF, and ADF digestibility and reduced daily methane emissions（L/kg BW0.75） in ewes, probably by decreasing the population of ruminal protozoans and methanogens.

Dose Response of Ruminal Microbial Flora and Metabolism of Sheep to Supplemental Polyacrylamide

[Objective] The paper was to test the effects of polyacrylamide(PAM) on ruminal microbial flora, activities of fibre-degrading enzymes and voluntary feed intake(VFI) of sheep. [Method] Five of 2-3 years old male Small-tail Han sheep, with body weight of(51.5±4.1) kg and fitted with permanent rumen fistula were used. By a 5×5 Latin square design, sheep were fed a basal diet supplemented with PAM at 0(control), 1.0, 2.0,3.0 and 6.0 g/kg diet, respectively. [Result] PAM supplementation affected VFI and ruminal indexes, and the peak values of them were at 2.0 g/kg diet by 17.9% for VFI, 56.6% for total bacteria, 18.3% for endocellulase, 19.4% for exocellulase and 16.5% for cellubiase( all P<0.05), respectively,compared with control. The NH3-N, protozoal counts, and the protease activity in rumen fluid were all linearly declined, but fungal counts increased linearly. No significant changes were found in pH, activities of xylanase and amylase of rumen fluid. The PCR copies of Fibrobacter succinogenes,Ruminococcus albus, Butyrivibrio fibrisolven and Selenomonas ruminantium increased to maximum of 21.4%, 22.7%, 22.6% and 20.6%(all above P<0.05), whereas these of Prevotella bryantii, Clostridium aminophilum, methanogens and microscopic counting of great coli decreased to maximum of 24.5%, 34.8%, 21.2% and 52.2%(all above P<0.05);but Salmonella bovis and Prevotella ruminicola were not affected by PAM. [Conclusion]PAM supplementation at 2.0 g/kg diet can reduce protozoa but increase bacteria, particularly those species for fibre digestion, and fungi in rumen.The effect of PAM on bacterial species was selective. These changes finally enhanced activities of enzymes for fibre digestion in rumen, and stimu-lated VFI of sheep, suggesting a potential application of PAM in ruminant production.

Enzymology properties of two different xylanases and their impacts on growth performance and intestinal microflora of weaned piglets

The enzyme xylanase is more and more widely used in feed production, but different xylanase have different properties, mechanism and application effects. To provide a theoretical basis for choosing more suitable xylanase in feed production, we selected bacterial xylanase(BX), labeled enzyme A, and trichoderma xylanase(TX), labeled enzyme B, and studied the enzymology properties and application effects on growth performance and gut flora in weaned piglets. The results showed that the activity levels of both appear parabolic along with increasing pH or temperature, but the amplitude of enzyme activity changing curves and the pH/temperature of optimal activity level are different, where enzyme A has the optimal activity level at 50 ℃ with a pH value of 5.0. The optimal activity level of enzyme B was achieved at 70 ℃ with a pH around 6.0. Enzyme B suffered very little activity loss with moisture level at16% and temperature from 80℃ to 90 ℃. Enzyme A suffered a big drop in activity level when processed with high temperature from around 80 ℃ to 90 ℃, and it was even completely inactivated at 90 ℃,Enzyme A has very low activity level after being processed in acid environment, but enzyme B has minor changes in activity level with respect to changes in acid level, indicating significantly different enzymatic properties between the two different sources of xylanases. In feeding experiment, the control group, was fed the basal diet, and the BX group and TX group were fed basal diets supplemented with 0,01% bacterial and fungal xylanases, respectively. The results showed that ADG of the BX group and TX group increased by 3.25%(P> 0.05) and 8.22%(P < 0.05), respectively, and the feed conversion ratio decreased by 6.74% and 7.86%(P > 0.05), respectively compared with the control group; TX group had significantly higher(P < 0.05) ADG compared with BX group; BX group and TX group had significantly lower ileum Escherichia coli level than the control group, which were reduced by up to 12.98%(P < 0.05) and 11.68%(P < 0.05), respectively, but the ileal lactic acid bacteria levels were significantly increased by 16.21%(P < 0.01) and 27.02%(P < 0.01),respectively. There were no significant differences(P > 0.05) between BX group and TX group in terms of lactic acid bacteria E. coli level. We concluded that fungal xylanase(enzyme B) has better performances in improving weaned piglet growth and in increasing ileal lactic acid bacteria level compared with bacterial xylanase(enzyme A).

Is Regular Probiotic Practice Safe for Management of Sepsis?

For decades,the gut has been thought to play an important role in sepsis pathogenesis.Sepsis is a serious life-threatening,chronic condition of an infection caused by dysregulated host immune response in most of the intensive care unit patients.Probiotics have dual roles in polymicrobial sepsis i.e.probiotics may induce sepsis in many cases and may prevent its prognosis in many cases.Experimental evidence from both pre-clinical and clinical studies have demonstrated that probiotic therapy ameliorates various inflammatory mediators such as tumor necrosis factor,interleukin-10(IL-10),IL-6,etc.,in septicemia.In addition,probiotic use was also found to reduce the severity of pathological conditions associated with irritable bowel disorder and prevent development of endocarditis in septicemia.On contrary,probiotic therapy in neonatal and athymic adult mice fail to provide any beneficial effects on mortality and sepsis-induced inflammation.Importantly,in few clinical trials probiotic use was found to aggravate sepsis by promoting inflammatory cascade rather than suppressing it.This review discusses various studies regarding the beneficial or harmful effects associated with probiotic therapy in sepsis.