Effect Of Pogostemon Cablin Essential Oil And Rhizoma Atractylodis Oil On Ruminal Fermentation And Nutrient Degradability In Jinjiang Yellow Cattle Under Heat Stress

The climate is hot, humid and rainy in southern summer, and feedlot cattle finished during summer months are often adversely affected by heat stress conditions. Heat stress induced animals digestive system disorder, nutrient utilization declined, severe diarrhea, decreased the growth performance of beef cattle. Rumen is an important organ of digesting and absorbing the nutrition in ruminant, and rumen fermentation has a decisive influence on ruminant nutrition. Our previous studies demonstrated that Pogostemon cablin, Rhizoma Atractylodis and other traditional Chinese medicine improved nutrient degradability and the growth performance of beef cattle under heat stress, but the influence mechanism were unclear. Some studies demonstrated that plant essential oil improved rumen fermentation on ruminant, and essential oil are the active ingredients of Pogostemon cablin and Rhizoma Atractylodis, but no reports are noticed about the effect of Pogostemon cablin and Rhizoma Atractylodis essential oil on regulating ruminal function. The objective of this study was to determine the effects of Pogostemon cablin essential oil and Rhizoma Atractylodis oil on ruminal fermentation and nutrient degradability of Jinjiang yellow cattle, probe the mechanism of the essential oil on ruminal fermentation, and provide theoretical basis on the application of essential oil in ruminant animal under hot environment of summer.Experiment 1:The objective was to determine the effects of Pogostemon cablin essential oil on ruminal fermentation and nutrient degradability of Jinjiang yellow cattle in vitro. An in vitro batch culture method was used in the study, and a basal diet with concentrate to forage ratio of 20:80 was supplemented with Pogostemon cablin essential oil by 0 (normal temperature control and high temperature group),0.25%,0.50%,0.75% and 1.00%, respectively.In this trial, the rumen fluid with nomal temperature control were taken from three fistula cattle fed under normal temperature environment, but other groups from three fistula cattle fed under high temperature environment. The results showed as follows:1) Ruminal fermentation:compared with control group, the concentrations of acetate, propionate, butyrate and total volatile fatty acids (TVFA) with high temperature group were increased, but pH value, concentrations of microbial protein (MCP) and ammonia nitrogendie (NH3-N) were decreased. However, compared with high temperature group, the total gas production with Pogostemon cablin essential oils was declined, rumen fluid pH value, the concentrations of MCP, NH3-N and TVFA were increased.2) Nutrient degradability:compared with control group, the degradability of DM and NDF with heat stress group were increased, but no difference was noticed about the degradability of CP and ADF. Compared with high temperature group, diet supplemental with Pogostemon cablin essential oils decreased the degradability of NDF and ADF, but no difference were noticed about the degradability of DM and CP.. These results indicated that high temperature environment declined the ruminal fermentation, but increased the nutrient degradability. While, diet supplemental with Pogostemon cablin essential oils improved ruminal fermentation, and decreased the nutrient degradability of Jinjiang yellow cattle under high temperature environment.Experiment 2:The objective of this study was to determine the effects of Rhizoma Atractylodis oil on ruminal ferment and nutrient degradability of Jingjiang cattle under high temperature environment. Experimental design was the same as the first experiment, but Rhizoma Atractylodis oil were supplemented by 0,0.25%,0.50%,0.75%and 1.00%, respectively. The results showed that:1) Ruminal fermentation:compared with normal control group, the pH value, concentrations of MCP, NH3-N and butyrate with high temperature group were increased, but acetate concentration were declined, and no difference was noticed about the total gas production and TVFA between high temperature group and control.2) Nutrient degradation:Compared with the control group, the degradability of DM and NDF with high temperature group were increased by 39.13% and 24.14%(P<0.01), but no difference was noticed about the degradability of CP and ADF. Diet supplemental with Rhizoma atractylodis oils by 0.75% increased the degradability of CP and ADF, but no difference were noticed about the degradability of DM and NDF comparing with high temperature group. These results indicated that high temperature environment declined the ruminal fermentation, and increased the nutrient degradability, but diet supplemental with Rhizoma atractylodis oils by 0.75% improved ruminal fermentation, and increased the nutrient degradability of Jinjiang yellow cattle under high temperature environment.Experiment 3:The objective of this study was to determine heat stress response of beef under high temperature conditions in summer.3 Jingjiang yellow cattle with normal temperature control group were fed in spring, while in summer, these cattle were randomly divided into three treatment groups by designing as a replicated 3×3 Latin square:high temperature control (HTC), Pogostemon cablin essential oil+high temperature (PCO I) and Rhizoma Atractylodis oil+high temperature (RAO) (n= 1 per group). The results showed that:1) Compared with normal control group, body temperatures, the rates of respiratory and diarrhea of Jinjiang yellow cattle in HTC group were increased significantly under high temperature environment in summer. There were a trend of decreasing about the rates of respiratory and diarrhea with Pogostemon cablin essential oil comparing with the HTC group.2) Ruminal fermentation:comparing with the HTC group, the proportion of acetic and propionic acid with Rhizoma Atractylodis oil was increased on day 5, and there was a trend of increasing about MCP contents and declining about NH3-N levels, but no difference was noticed about the contents of VFA and pH value among three groups.3) Nutrient degradability:there were a trend of increasing about the degradability of DM, NDF and ADF with Pogostemon cablin essential oil, but no difference was noticed about the degradability of CP comparing with the HTC group. Meanswhile, there was a trend of declining about nutrient degradabilities with Rhizoma Atractylodis oil compared with HTC group. These results indicated that high temperature and humidity environment induced heat stress response of beef cattle, diet supplemental with Pogostemon cablin essential oil and Rhizoma Atractylodis oil by 1g/kg improved ruminal fermentation, but did not affect the degradabilities of nutrient of Jinjiang yellow cattle.