Effects Of Mentha Haplocalyx.Briq Extracts On Physiology, Biochemical Response And Performance Of Finishing Pigs

This experiment was designed to study the mechanism of heat stress on finishing pigs, and discuss the role and mechanism of Mentha haplocalyx. Briq Extracts. The experiment was conducted in the present study to investigate the mechanism of heat stress in. pigs, including performance, serum biochemical indexes, endocrine hormones, and physiology response.In the hot seasons, by observing the influence on the developments regular of biochemical parameters, the effect on digestive system, on the respiratory system, on the endocrine system, so as to offer some theory basis on alleviating heat stress and farther developing anti-heat stress herbs with low poison and side-effect, convenient and remarkable benefit.The experiment used single factor trial design. According to sex and weight, 180 three- way crossbred [Duroc×(Landrace×Yorkshire)] finishing pigs ( about 70±3 kg body weight) , were divided into five groups randomly, with three replications per group and 12 pigs per replication. Pigs of the control group were fed a basal diet and the trial groups fed on basal diet supplemented with 12.5 mg/kg, 25 mg/kg, 50 mg/kg, 100 mg/kg Mentha extracts, respectively. The experiment lasted 42 days. In addition, the digestive experiment with acid insoluble ash as indicator was conducted for three days during the 39-42th days. Plasma was taken at 21 day and 42 day.At an ambient temperature of 27.9 - 32.4℃, ambient humidity of 70.51%, rectal temperature of trial group decreased, except 12.5 mg/kg group. Comparing to the control group, Mentha extracts adding 50mg/kg and 100mg/kg group, rectal temperature changed significantly, 0.19℃and 0.17℃lower than control. Compared to the first stage (the first three weeks), rectal temperature of trial group decreased much more than that at the second stage, especially to the boar. Rectal temperature of boar in 100mg/kg trial group fell 0.76℃lower than that of first stage and 0.34℃lower than that of control (P=0.014) . Rectal temperature of boar in 50mg/kg trial group fell 0.36℃lower than that of first stage and 0.22℃lower than that of control(P=0.11). With the ambient temperature decreasing a little, the rectal temperature of finishing pigs played down.The result of breath frequency of finishing pigs indicated that adding Mentha extracts group relaxed to some extent under heat shock. 100mg/kg group eased 15 times per minute less than the control (P=0.012). Compared to the first stage (the first three weeks), breath frequency of trial group decreased much more than breath frequency at the second stage. Breath frequency of 100 mg/kg group reduced 17 times per minute less than the control (P=0.007).Comparing to the control group, ADFI, ADG showed a little lower and F/G a little higher than the control group. Feed/Gain of 12.5 mg/kg and 100 mg/kg trial group rised dramatically, comparing to the control. The productive performance of trial group seems no significant difference. The nutrients (GE, CP) digestibilities were detected and had no clearly difference (P>0.05). The results showed that Average Daily Feed Intake (ADFI) gradually cut down at the first stage and improved at the second stage to approach the same level. Compared to the control, 12.5 mg/kg and 100 mg/kg trial group decreased 16.99% and 15.53% respectively (P<0.05) at the first three weeks. ADFI of the control group and trail groups had a increasing current at the second stage, 33.92%, 20.54%, 11.79%, 31.03% much higher than that at the first stage. However contemporary records of the control was 8.28%.Studies showed that heat stress could increase the concentration of serum Na⁺ and Cl^-, and decreased the concentration of serum K⁺, Ca²⁺, Mg²⁺. But influence of Mentha extracts on inorganic ions concentration in serum was very intricate. Premix of Mentha extracts had no good significant effects on serum Ca²⁺, Mg²⁺, Cl^-. 100mg/kg trail group could alleciate the effects of heat exposure on inorganic ions concentration in serum.Exposed to high environmental temperature, studies showed that heat stress could dramatically increased the concentration of serum ALT, AST, LDH and CK. Adding Mentha extracts could attempt to abate AST, LDH and CK level in the second stage, especially for the dose of 100 mg/kg. Compared to the control, Serum CK significantly increased at the first three weeks but significantly decreased at the second three weeks.The serum concentration of TBA decreased in the second phage, but adding Mentha extracts could weaken the decreasing trend. Comparing to the control group, TBA of the trial group decreased in the first phage, 25 mg/kg and 100 mg/kg significantly decreased.Under heat exposure, results confirmed that heat stress could reduce the concentration of serum T3, T4. Results showed no obvious change to finishing pigs for adding Mentha extracts. Cor increased based on lasting heat exposure. It was found increased at the first three weeks and decreased at the next three weeks in the trial group.