Effects Of Tea Tree Oil On Growth Performance,Serum Biochemical Parameters And Meat Quality Of Finishing Pigs

This experiment studied the influence of the Australia tea tree oil(Extracted from Australian Melaleuca Alternefolia,commonly known as Tea Tree Oil)on growth performance,meat quality,serum biochemical,antioxidatant indexes,immune indexes and related genes' mRNA level.1.Effects of tea tree oil on growth performance and growth-related genes'mRNA expression of finishing pigs64 castrated "Duroc×Landrace×Yorkshire" finishing pigs used with similar initial body weight(68.13±0.46)kg were selected in this experiment,they were randomly assigned to 4 groups with 4 replicates per group and 4 pigs per replicate(half male and half female).The pigs were fed 4 formulated diets contained a basal diet(control group)and 3 experimental diets,which were basal diets supplemented with 100 mg/kg,200 mg/kg and 300 mg/kg tea tree oil,respectively.The feeding transition period lasted for 10 days and the feeding period lasted for 56 days.(Result)The results showed as follows:(1)compared with the control group,final weight and average daily gain in 200 mg/kg and 300 mg/kg groups were significantly increased(P<0.05),and the feed/gain in 100 mg/kg and 200 mg/kg groups were significantly reduced(P<0.05).(2)the liver indexes of 200 mg/kg and 300 mg/kg groups were significantly higher than that of the control group(P<0.05),and the kidney indexes of 300 mg/kg group was significantly higher than that of the control group(P<0.05).(3)The CP of 100 mg/kg group and the EE of 200 mg/kg group were significantly increased than that of the control group.(4)In liver,the IGF-I mRNA expression of 100,200,300 mg/kg groups were significantly increased than that of the control group(P<0.05),and the MSTN mRNA expressiom of 300 mg/kg group were significantly decreased than that of the control group(P<0.05).The GH mRNA expression of 200 mg/kg group also tended to increase(P<0.1).In longissimus dorsi,the GH mRNA expression of 200 mg/kg and 300 mg/kg groups were significantly increased than that of the control group(P<0.05),and the IGF-I mRNA expression of 200 mg/kg group also significantly increased than that of the control group(P<0.05).The MSTN mRNA expression of 300 mg/kg group also tended to increase(P<0.1).2.Effects of tea tree oil on serum biochemical parameters and antioxidant capacity of finishing pigsThe blood was sampled from precaval vein to test serum biochemical parameters,antioxidant and immune indexes The results showed that:(1)supplement 200 mg/kg and 300 mg/kg dosage of TTO on the diet significantly decreased the serum AST concentration(P<0.05);supplement 200 mg/kg dosage of TTO on the diet significantly increased the ALP concentrations on the 28th day(P<0.05).(2)Serum TP concentration was significantly increased in three experiment groups on the 28th day and serum GLOB concentration was significantly increased in 100 mg/kg group on the 56th day(P<0.05).Serum CERA concentration was significantly deceased in 200 mg/kg group on the 28th day and 56th day.(3)On the 28th day of experiment period,after supplemented 200 mg/kg and 300 mg/kg TTO the GLU concentration was significantly decreased and 200 mg/kg group TG concentration was significantly decreased(P<0.05).(4)On 28th day,the concentration of IgG in 200 mg/kg group was significantly increased and the concentration of IgM in 100 mg/kg and 200 mg/kg groups were significantly increased(P<0.05).On the 56th day,the concentration of IgG in experiment groups were significantly increased than those in the control group.(5)The concentration of MDA of serum in group 200 mg/kg and 300 mg/kg was significantly lower than that of the control group(P<0.05),but the concentration of GSH-Px was on the contrary.The concentration of GSH-Px of Longissimus dorsi in group 200 mg/kg was significantly higher than that of the control group(P<0.05).The experimental results suggest that TTO supplementation in the diet of finishing pigs can regulate serum metabolism and immune function.3.Effects of tea tree oil on meat quality and meat-related genes' mRNA expression of finishing pigsLongissimus dorsi was sampled after the pig was slaughtered,and determination the meat-related genes' expression in liver,longissimus dorsi and back fat.The results showed as follows:(1)Compared with the control group,the redness value and pH24 h in 200 mg/kg group were significantly increased(P<0.05),and the intramuscular fat of longissimus dorsi muscle in 100 mg/kg and 200 mg/kg groups was significantly higher than that of the control group(P<0.05),but the shear force was on the contrary.(2)Compared with the control group,the asparaginic acid and alanine of 200 mg/kg group was significantly increased(P<0.05),the threonine,leucine,and phenylalanine of 200 mg/kg,300 mg/kg groups were significantly increased(P<0.05),The total amino acids of 200 mg/kg group also tended to increase(P<0.1).(3)Compared with the control group,the C16:0 of 100 mg/kg,300 mg/kg groups were significantly increased(P<0.05),the C18:2n6t of 100 mg/kg,200 mg/kg and 300 mg/kg groups were significantly increased(P<0.05).(4)In liver,the A-FABP mRNA expression of 100 mg/kg group was significantly increased than that of the control group and other trail groups(P<0.05).The H-FABP mRNA expression of 200 mg/kg,300 mg/kg were significantly increased than that of 100 mg/kg group(P<0.05).In longissimus dorsi,compared with the control group,the CAPN1 mRNA expression of 300 mg/kg group was significantly increased than that of the control group(P<0.05),the H-FABP,A-FABP mRNA expression of 200 mg/kg group was significantly increased than that of the 300 mg/kg group(P<0.05).In back fat,The HAL mRNA expression of 100 mg/kg,200 mg/kg were significantly increased than that of the control group.The CAST mRNA expression of 100 mg/kg was significantly increased than that of the control group,The A-FABP mRNA expression of 100 mg/kg group also tended to increase(P<0.1).To sum up,tea tree oil can improve the growth performance and meat quality of finishing pigs.-Its mechanism might be related with the effects on regulating growth-related and meat-related genes' mRNA expression and reducing antioxidant stress.Appropriate dosage of tea tree oil indiet was 200 mg/kg.