Effect Of Dietary Selenium Supplementation On Growth Performance, Antioxidant Indices, Meat Quality, Blood Biochemical Parameters And Liver Gsh-Px1 MRNA Expression Of Meat Rabbits

The experiment was designed to study the effect of dietary different selenium supplement levels on production performance, antioxidant indices, meat quality blood metabolites, serum hormone concentration and liver GPX mRNA expression of weaned to 3 months old meat rabbits. One hundred and twenty weaned growing meat rabbits were allocated to individual cages and randomly divided into five groups. Animals in each group were fed with a diet with the following selenium additional levels: 0, 0.15, 0.30, 0.45 and 0.60 mg/kg selenium in original matter basis respectively. The results were as follows.Dietary selenium levels significantly affected average daily gain (ADG) and feed/gain (P=0.0294, P=0.0156), however, selenium supplementation had no influence on average daily intake (ADFI) (P=0.3966). Selenium supplementation had significant influence on liver selenium concentration (P<0.0001), with the highest concentration in 0.45 mg/kg group. Dietary selenium supplementation significantly affected liver and serum GPX (P<0.0001, P=0.0281), but had no influence on their superoxide dismutase (SOD) (P=0.1319, P=0.8848). Liver and serum total antioxidant capacity (T-AOC) and catalase (CAT) (P=0.0406, P=0.0414) was significantly affected by dietary selenium supplementation. Liver malondialdehyde (MDA) (P=0.0018) tend to be higher in control group than in selenium supplementation groups. There was no significant difference on serum total protein (TP) (P=0.2401). Selenium supplementation can reduce serum total cholesterol (TC) (P=0.0349), triglyeride (TRI) (P=0.0001) and low density lipoprotein (LDL-C) concentration (P=0.0055), and at the same time increase the concentration of high density lipoprotein (HDL-C) (P=0.0077). Selenium supplementation significantly affect liver GPX m RNA expression (P<0.0001). In conclusion, the appropriate dietary selenium supplement level of weaned to 2 month-old meat rabbits was 0.15 mg/kg (The concentration of selenium in basal diet was 0.08 mg/kg).Different levels of selenium supplementation had no significant difference on rabbits'average daily food intake (ADFI) (P=0.1202), but average daily gain (ADG) and feed/gain were significantly better when selenium levels were 0.15 and 0.30 mg/kg (P=0.0194, P=0.0401). The dietary selenium levels had significant influence on glutathione peroxidase (GSH-Px) activity of liver, serum and muscle (P=0.0114 , P=0.0009, P<0.0001), superoxide dismutase (SOD) activity of liver and serum (P=0.0323, P=0.0149) and catalane (CAT) activity of liver (P=0.0434). The malonaldehyde (MDA) content of liver and muscle (P=0.0291, P=0.0190) and the total antioxidant capacity (T-AOC) (P=0.0376) were significantly affected by the dietary selenium levels. The dietary selenium levels had significant influence on muscle water loss ratio (P=0.0325) and drip loss (P=0.0042) and the muscle water loss ratio in 0.15 mg/kg group was lower than those in no add of selenium and 0.60 mg/kg groups. The shear value of muscle was significantly affected by the dietary selenium levels (P=0.0285) and the value in selenium supplemented groups were lower than that in no add of selenium group. With the increase of dietary selenium levels, the selenium concentration of the muscle and liver increased with the highest concentration in 0.30 mg/kg selenium added group. Rabbits'serum total cholesterol (TC) (P=0.0497) and density lipoprotein (LDL-C) (P=0.0386) were lower and serum total protein (TP) (P=0.0338), high density lipoprotein (HDL-C) (P=0.0235) was higher when feed forage supplemented with different selenium levels. Dietary selenium supplementation had no influence on triglyeride (TRI) (P=0.0895). Selenium supplementation can low the concentration of serum tetraiodothyronine (T4) (P=0.0327), and increase the concentration of serum triiodothyronine (T3) (P=0.0107), but it had no influence on serum thyrotrophic-stimulating hormone (TSH) (P=0.5981). Liver GSH-Px mRNA expression of 2 to 3 month-old rabbits was significantly affect ted by different selenium supplementation levels (P<0.0001), with the highest expression in 0.15 mg/kg group. In conclusion, the appropriate supplementation of selenium in diet of 2 to 3 months old growing meat rabbits was 0.15 mg/kg (The concentration of selenium in basal diet was 0.08 mg/kg).