Dose-effect Study of Lipoic Acid Supplementation on Growth Performance in a Weaned Rat Model

The present study investigated the doseeffect relationship of graded levels of lipoic acid supplementation on growth performance and small intestinal development in a weaned rat model. Seventy-two weaned Sprague-Dawley rats, were fed semipurified diets （ n = 12 ）, either unsupplemented （ group I） or supplemented with 12.5,25,125, or 250 mg/kg body weight （ BW ） lipoic acid （ groups HI, IV, V, and VI）, with 200 mg/kg BW aureomycin as the antibiot- ic control （ group II）. The experiment lasted 21 days. Growth performance was not significantly different （P 〉 0.05） between rats under the antibiotic control （group I） and rats fed low levels （12. 5 and 25 mg/kg BW） of lipoic acid （groups III and IV）. In contrast,high level （125 and 250 mg/kg BW） lipoic acid supplementation （groups V and VI） （P 〈 0.05 ） reduced weight gain, feed consumption, and feed efficiency. In addition, high levels （125 and 250 mg/kg BW） of lipoic acid significantly （P 〈 0.05） reduced the villus height/crypt depth ratio, as well as the numbers of lactobacillus, total aerobes, and total anerobes in the gastrointestinal tract compared with the other treatments, which meant that high levels of lipoic acid impaired intestinal morphology and disordered the balance of intestinal microbiology. Furthermore,the results showed that high levels of lipoic acid supplementation （ P 〈 0.05 ） elevated interferon- γ and interleukin-2, but dramatically （ P 〈 0.05 ） depressed interleukin-4 and interleukin-10 compared with the low levels of lipoic acid supplementation and the control group, which indicated that high levels of lipoic acid would induce bias of Th1/Th2 lymphocytes. Taken together, the results indicate that lipoic acid supplementation can＇ t improve growth performance and intestinal development of normal animals, especially,high levels （ ≥ 125 mg/kg BW） of lipoic acid supplementation restrained growth performance and intestinal development, in association with unbalance of certain cytokines.

Preventive effects of the polysaccharide of Larimichthys crocea swim bladder on carbon tetrachloride(CCl_4)-induced hepatic damage

The aim of the present study was to determine the preventive effects of the polysaccharide of Larimichthys crocea swim bladder(PLCSB) on CCl4-induced hepatic damage in ICR mice.The in vitro preventive effects of PLCSB on CCl4-induced liver cytotoxic effect were evaluated in BRL 3A rat liver cells using the MTT assay.The serum levels of AST,ALT,and LDH in mice were determined using commercially available kits.The levels of IL-6,IL-12,TNF-α,and IFN-γ were determined using ELISA kits.The pathological analysis of hepatic tissues was performed with H and E staining,and the gene and protein expressions were determined by RT-PCR and Western blotting,respectively.PLCSB(20 μg·m L-1) could increase the growth of BRL 3A rat liver cells treated with CCl4.The serum levels of AST,ALT,and LDH were significantly decreased when the mice were treated with two doses of PLCSB,compared with the control mice(P < 0.05).PLCSB-treated groups also showed reduced levels of the serum pro-inflammatory cytokines IL-6,IL-12,TNF-α,and IFN-γ.PLCSB could decrease the liver weight,compared to the CCl4-treated control mice.The histopathology sections of liver tissues in the 100 mg·kg-1 PLCSB group indicated that the animals were recovered well from CCl4 damage,but the 50 mg·kg-1 PLCSB group showed necrosis to a more serious extent.The 100 mg·kg-1 PLCSB group showed significantly decreased mR NA and protein expression levels of NF-κB,i NOS,and COX-2,and increased expression of IκB-α compared with the CCl4-treated control group.In conclusion,PLCSB prevented from CCl4-induced hepatic damage in vivo.