Effects Of Lactic Acid Bacteria On Meat Quality And Immune Gene Expression Of Rex Rabbits

Lactic acid bacteria, as a kind of probiotics that has longest history and most widly application scope,with good effect on growth, immune and production performance for livestock, which has high value inanimal production and has important significance on developing environment protecting animalhusbandry. This experiment studies the effects of lactic acid bacteria on digestion, antioxidant capacity,sensory quality of meat and spleen immune-related genes, and mRNA relative expression of IGF-1, IGF-1R,GHR in musculature of the rex rabbits. To research the mechanism on growth and immune of the rabbits, aswell as the appropriate dosage. A total of eighty healthy white rex rabbits with43days of age wereaccording to the principle of male female half randomly divided into5experimental groups. the test groupsⅠ、Ⅱ、Ⅲ、Ⅳ were fed basal diet supplemented with104,107,1010and1013cfu/ml lactic acid bacteria,respectively. The C group is control group, was fed basal diet with physiological saline and once everyother day to feed10ml each time. Sampling at the30th day and the60th day, selected4slaughter samplingsof each group randomly. The alimentary canal contents, blood, muscle was collected to measure digestiveenzyme, autioxidant enzyme activities and meat quality. spleen and muscle was collected, then total RNAwas extracted and reverse transcription. The relative expression of IFN-γ, IL-2, IGF-1, IGF-1R and GHRgene was detected with real-time fluorescence quantitative PCR method. The results showed as follows:(1) Lactic acid bacteria could improve the sensory quality of meat. Compared with the control group, thedriage of test Ⅰ and Ⅱ group significantly decreased4.49%and2.27%(P<0.05), respectively. While，there was no significant difference effect on PH, shear force and color of the meat（P>0.05）.(2) Lactic acid bacteria could increase the activity of digestive enzymes in jejunal. About80-day-old rexrabbits, lactic acid bacteria improved the activity of amylase and lipase in jejunum, but no significant effectof trypsin and chymotrypsin (P>0.05), amylase activity of test group Ⅱ and lipase activity of test groupⅢ were significantly higher than that of the control group (P<0.05). About110-day-old rex rabbits, lacticacid bacteria increased lipase activity and trypsin activity, but no significant effect on amylas in jejunum,lipase activity of each test groups and trypsin activity of test group Ⅲ are higher than that of the controlgroup, significantly (P <0.05). At80and110days of age, lactic acid bacteria had no significant effect oncellulase activity of caecum in rex rabbits (P>0.05).(3) Lactic acid bacteria increased the activity of antioxidant enzyme in plasma of rex rabbits. At80days ofage, the GSH-PX activity of test group Ⅲ was higher than that of control group, significantly (P<0.05).MDA level of each test groups was lower than that of control group, significantly(P<0.05). At110days of age, compared with the control group, GSH-PX activity of each test groups raised significantly (P<0.05),and MDA levels of each test groups dropped significantly (P<0.05).(4) Lactic acid bacteria could enhanced the expression of IFN-γ and IL-2gene in spleen of rex rabbits. At80days of age, IFN-γ expression of Ⅱ, Ⅲ, Ⅳ test group was higher than that of control groupsignificantly (P<0.05), and that of group Ⅲ was the biggest, IL-2expression of test group Ⅲ was higherthan that of control group significantly (P<0.05), the rest test groups and the control group had nosignificant difference (P>0.05). At110days of age, IFN-γexpression of Ⅲ, Ⅳ test group was higherthan that of control group significantly (P<0.05), and that of group Ⅲ was the biggest, IL-2expression oftest group Ⅱ was higher than that of control group significantly(P<0.05), the rest test groups and thecontrol group had no significant difference (P>0.05).(5) Lactic acid bacteria improved mRNA relative expression of IGF-1and GHR, the mRNA relativeexpression of IGF-1in test groups Ⅰ was maximum, the mRNA relative expression of GHR in testgroups Ⅱ was maximum, both of which were exceed the control group significantly (P<0.05). But, Therewas no significant different effect on mRNA relative expression of IGF-1R（P>0.05）.In conclusion, lactic acid bacteria could enhance the antioxidant capacity, could increase the digestiveability and improve the meat quality of rex rabbits. From the perspective of molecular biology, lactic acidbacteria could promote mRNA expression of IFN-γ, IL-2, IGF-1and GHR gene, and then could strengthenthe immune performance, influence the growth rate of muscle and the characteristics of myofiber. Theappropriate supplemental level of lactic acid bacteria is107cfu/ml, and the recommend range is107~1010cfu/ml under this experimental condition.