Effects Of Flaxseed Lignan On The Metabolism And Growth Performance Of Animals And Its Possible Mechanism

To investigate their respective effects of defatted flaxseed meal (DFFS), flaxseed lignan crude extract (SDGCE) and flaxseed lignan (secoisolariciresinol diglucoside, SDG) on the growth performances in animals, rats were used as non-ruminant animal model. The studies on their causal mechanicsms were focused mainly on the endocrine pathway. And high performance liquid chromatography (HPLC) was used for analyzing the metabolism and absorption of SDG in non-ruminant. Meanwhile, goat was used as ruminant animal model, HPLC, denatureing gradient gel electrophoresis (DGGE), radioinnunoassay (RIA) and gas chromatography (GC) were used to analyze the relationships between the convertation of lignans, ruminal flora, hormones and ruminal metabolism in goats, thereby to understand more fully about the effect of lignans on ruminal metabolism.1 Effects of defatted flaxseed meal on the growth performances and related hormones in animalsAs a pretesting experiment, the aims of this study were to observe the impacts of defatted flaxseed meal (DFFS) on the growth performances, lipid metabolism and related hormones in experimental animals. The data show that DFFS could promote the growth of male animals via neuroendocrine pathway, and elevate the activities of lipid metabolism-related enzymes, thereby induce the lipid mobilization and inhibit the fat deposition in rats and mice. But it may inhibit the growth of female mice.1.1 SeriesⅠEffects of DFFS on the growth performances and related hormones in mice 100 mice (ICR,22 day-old) were assigned randomly to 4 groups (25 mice per group). In the control group, mice were fed basal diet, while DFFS treatment groups were supplemented with DFFS (2 g/kg,5 g/kg, and 10 g/kg basal diet, respectively).The experiment lasted 4 weeks. The data show that DFFS could significantly increase the feed efficiency and the body weight gain in male mice, but inhibit the growth of female mice. These may suggest that DFFS may possess gender-related different effects on animal growth performance. Meanwhile, DFFS could decrease the serum low density lipoprotein (LDL) content (P<0.05) and total cholesterol (TC) level (P<0.05), increase the activity of hepatic lipase (HL, P>0.05) in serum, and thereby inhibit the fat deposition in mice. DFFS could also upgrade the levels of serum testosterone (T, P<0.01) and growth hormone (GH, P>0.05), consequently, promote the muscle growth in male mice. The result may indicate that mice supplemented with DFFS in basal diet could increase the feed efficiency, affect the activities of lipid metabolism-related enzymes, and thereby inhibit the fat deposition. DFFS may promote the growth of males via neuroendocrine pathway.1.2 Series II Effects of DFFS on the growth performance and related hormones in rats32 male Sprague-Dawley (SD) rats (6 month-old), were assigned randomly to 4 groups (8 rats per group). Control group mice were fed with basal diet, while DFFS treatment groups were supplemented with DFFS (2 g/kg,5 g/kg, and 10 g/kg basal diet, respectively). The experiment lasted 4 weeks. The data show that DFFS could significantly increase the feed efficiency and the body weight gain in male rats, and significantly increase serum T (P<0.01) concentration and GH (P<0.05) contents. Meanwhile, DFFS could decrease the serum LDL level (P<0.01) and increase serum high density lipoprotein (HDL) concentration (P<0.05) and the activity of HL (P<0.05) in serum, and thereby inhibit the fat deposition. These may suggest that basal diet supplemented with DFFS could increase the feed efficiency, affect the activities of lipid metabolism-related enzymes, and thereby inhibit the fat deposition. DFFS may promote the growth of males via neuroendocrine pathway. 2 The metabolism and absorption of flaxseed lignan in non-ruminant animalsThe objective of current study was to investingate the relationship between germ in gastrointestinal tract (GIT) and flaxseed lignan, and the metabolism and absorption of lignans in non-ruminants. The rats, which had been adaptated to secoisolariciresinol diglusoside (SDG) for 7 d, were used as a model for non-ruminant animal. Two series of experiments were conducted to analyze the concentrations of SDG, enterodiol (END) and enterolactone (ENL) in GIT, faeces, bile and serum in rats with or without antibiotics. The results shows that the colon and caecum, which contain the most germs in GIT, produced the most mammalian lignans, and the formations of mammalian lignans depend on the GIT micro flora. The level of flaxseed lignan in serum was higher than that of END or ENL, and the antibiotics can significantly inhibit the absorption and convertation of flaxseed lignan. Once the flaxseed lignan and mammalian lignans were absorbed, they could undergo enterohepatic circulation.3 Effects of flaxseed lignan crude extract on the growth performance and related hormones in rats72 male SD rats (28 day-old), were assigned randomly to 6 groups (A～F,6 males and 6 females per group). Group A rats were fed basal diet, while in group B, C and D, the basal diet were supplemented with SDGCE (125 mg/kg,250 mg/kg, and 500 mg/kg basal diet, respectively). The experiment lasted 5 weeks. The data shows that SDGCE may facilitate the body weight gain, and improve the feed efficiency; serum urea-nitrogen (urea-N) were decreased (P<0.01) gy SDGCE, while serum testosterone (T, P<0.01) and growth hormone (GH,P<0.05) contents, and the activity of serum glutamate-pyruvate transominase (GPT, P<0.05) were significantly increased, the RNA/DNA ratio in muscle were also increased (P<0.05) by SDGCE in male rats, these may indicate that SDGCE could increase serum T and GH level, and consequently induce the protein synthesis in muscle and inhibit the albuminolysis, and promote the fuse of sarcoblast and muscle fibril. Meanwhile, SDGCE could remarkably increase the serum leptin content (P<0.05) and the activities of hepatic lipase and lipoprotein lipase in serum (P<0.05),the serum free fatty acids (FFAs) in female rats were reduced (P<0.05) by SDGCE, however the FFAs seems like to be increased in male rats, it may suggest that SDGCE may induce the lipid mobilization and inhibit fat deposition in males, but it may play positive effects on fat deposition in females;Besides, SDGCE could increase the serum osteocalcin level (P<0.05) and the alkaline phosphatease activeities (P<0.05), reduce the blood calculus concentration (P<0.05) in rats. These may indicate that, SDGCE could promote the growth of skeletal muscles and bones, and affect the lipid metabolism via the neuroendocrine pathway in rats.4 Effects of flaxseed lignan on the growth of skeletal muscle in male rats and its possible mechanismTo determine the effects of flaxseed lignan on the growth of skeletal muscle in male animals, and its possible mechanisms. The impacts of the flaxseed lignan on skeletal muscle in male rats were determined in vivo. Daidzein (5ppm) and flaxseed lignan (50ppm) were added into the basal diets, and the concentrations of the serum lignans and daidzein were measured by HPLC, serum growth hormone and testosterone (T) levels were analyzed by RIA, and the expression of estrogen receptorβ(ERβ) in the soleus muscle and hypothalamus were determined by RT-PCR. Meanwhile, the impacts of lignans on skeletal muscle cell were analyzed in vitro. The data show that flaxseed lignan could significantly improve the feed efficiency ratios and facilitate the total weight gain of the femoral muscle in male rats. The rate of RNA to DNA in muscles and serum T levels were remarkably increased, while the urea nitrogen concentrations were significantly decreased by daidzein and flaxseed and/or its lignan. Meanwhile the expression of estrogen receptorβ(ERβ) in soleus muscle and hypothalamus were both upgraded by the two phytoestrogens. In vitro, low levels of lignans or daidzein could promote the growth of skeletal muscle cells. It was concluded that flaxseed lignan and Da may possess similar physiological functions in male rats. SDG and/or its metabolites could promote the growth of male rats, and this may occur via the neuroendocrine pathway. Their positive effects on skeletal muscle may involve direct (ERβ-related) or indirect (hormone-related) mechanisms. 5 The metabolism of flaxseed lignan in rumen and its impacts on ruminal flora and metabolism in goatsTo investigate the metabolism of lignans in the rumen and its impact on ruminal metabolism,6 healthy Huainan goats (4♂,2♀), with permanent rumen fistulae and temporary catheter in jugular vein were used in a crossover study. Twice a day during the treatment period,50 mg·kg-1 body weight secoisolariciresinol diglusoside crude extract (SDGCE) was infused into the rumen of the goats via the fistulae. Result:(1) The were low levels of secoisolariciresinol diglusoside (SDG), enterodiol (END) and enterolactone (ENL) in ruminal fluid under the basal diet conditions, and their concentrations were 0.003 mg·mL-1、0.017mg·mL-1 and 0.007 mg·mL-1, respectively, whereas the concentrations of all 3 lignans were below the level of detection in serum. Exposure to SDGCE could significantly increase the concentrations of lignans both in serum and ruminal fluid. (2) After exposure to SDGCE, the levels of pH and NH3-N were lowered byl.1%(P<0.05) and 36.3%(P<0.01),and the concentrations of microbial crude protein (MCP) and total volatile fatty acids (TVFA) were increased by 70.1%(P<0.05) and 37.4%(P<0.01), respectively,and the total activity of dehydrogenase (TDHA) was also increased by 25.5% (P>0.05) in ruminal fluid. (3) Furthermore, testosterone and 3,3’,5-triiodothyronine levels in serum and ruminal fluid were both significantly increased, although no marked change in serum thyroxine concentration was observed. The estradiol concentration in the rumen was 5.431±2.209 pg·mL-1 in male goats fed a basal diet; however, this decreased significantly by 161.19%(P<0.01) following SDGCE treatment. (4) SDGCE could significantly increase the mumber of predominat bands in the DGGE profiles and their Shannon index of general fiversity. Based on these observations, it is suggested that ruminal microorganisms efficiently convert SDG to END and ENL. In return, SDG and/or the 2 main mammalian lignans may directly or indirectly influence the activity of the microorganisms, thereby facilitating the utilization of nonprotein nitrogen and carbohydrates in the rumen.