| Hericium caput-medusae(Bull.:Fr.) Pers. that belongs to the genus Hericium is a well known edible and medicinal mushroom, the fermentation concentrate of this fungus has good effects on treatment gastrointestinal disease, and improvement body immunity. Polysaccharide is an important basis for the effects of the fermentation concentrate of Hericium caput-medusae(Bull.:Fr.) Pers. In recent years, some researchs indicated that polysaccharides from the fermentation concentrate of Hericium caput-medusae(Bull.:Fr) Pers. has the effects of antitumor, antioxidate, immune adjustment, and antibacte.The molecular mass range of HFCP was fractionated in this study, and 5 polysaccharide components of molecular mass range were obtained, including less than 5000 D, 5000 D to10000D, 10000 D to 20000 D, 20000 D to 50000 D, and more than 50000 D. The phenol-sulfuric acid method was used to measure the polysaccharide content of HFCP and different molecular mass components. The content of polysaccharide of HFCP was 77.5% of the dry weight. The polysaccharide content of different molecular mass components was obvious different, and the highest content was in the range of less than 5000 D, with 97.7% of the total sugar amount. The polysaccharide content of different molecular mass components ranked as follows: less than5000 D > 5000 D to 10000 D > more than 50000 D > 10000 D to 20000 D > 20000 D to 50000 D.The Coomassie brilliant blue G250 staining methord, Elson-Morgan method, Sulphuric acid- between hydroxyl diphenyl method, and Barium chloride- gelatin turbidimetry were used to determine the content of soluble protein, aminosaccharide, uronic acid, and sulfate radical of HFCP and different molecular mass components. The results showed that, the content of soluble protein, aminosaccharide, and uronic acid was low in HFCP, with 0.31%, 0.61% and 0.64% of the dry weight respectively. The sulfate radical of HFCP was higher, with 7.20%. The highest content of soluble protein was in the range of more than 50000 D, and the highest content of aminosaccharide, uronic acid, and sulfate radical was in the range of less than 5000 D, which was in accordance with the molecular mass range of the highest polysaccharide content component.The content of some active ingredients, including polysaccharide, polyphenol, and flavone of HFC were measured, which could give some basis for the application research of HFC. The content of polysaccharide, polyphenol, and flavone of HFC were 18.0%, 5.43 mg/g, and 2.05mg/g of the dry weight. In order to solve some pratical problems in agricultural production,broilers were used as the experimental animals in this study. For several decades, thecommercial broiler industry has focused on enhancing bird growth rate and feed conversation efficiency. However, this breeding strategy has led to inevitable problems, such as the decline of meat quality and the increase of concomitant body fat deposition. The relatively larger amount of body fat in broiler products, which are risk factors for obesity, diabetes, and cardiovascular diseases, is not welcomed by consumers. Furthermore, the discarded abdominal and viscera fat increases waste management problems. In recent years, there has been increased awareness of the benefits of functional additives to reduce fat deposition, and improve the carcass quality of broilers.The present study was designed to investigate the effects of dietary supplementation with polysaccharides from the fermentation concentrate of Hericium caput-medusae(Bull.:Fr.)Pers.(HFCP) on fat and cholesterol deposition of Arbor Acres broilers. In addition, the fermentation concentrate of Hericium caput-medusae(Bull.:Fr) Pers.(HFC) without polysaccharides extracting process but in the doses of polysaccharides addition was added to the broilers diet in order to save additive cost, and the effects of HFC on lipid metabolism,antioxidant status and meat quality of broilers were studied, which would provide the basis for the production of lower fat deposition broilers and the exploitation of fungi crops as feed additives.The experimental animal group situation in the HFCP feeding test were as follows: a total of 480 one-day-old Arbor Acres broilers were randomly divided into 4 dietary treatments(20broilers per pen with 6 pens per treatment): control group(basal diet), and three levels of HFCP(basal diet supplemented with 0.1%, 0.3%, and 0.5% of HFCP). The experiment lasted for 42 d.All parameters were recorded on day 21 and 42.Through the study of the effects of HFCP on serum lipid indexes, abdominal fat, short chain fatty acids(SCFA) in caecum, and lipid content in liver, muscles and excreta of broilers,the results revealed that: 1) Dietary supplementation with 0.3% and 0.5% of HFCP significantly decreased serum triglyceride(TG) content(P<0.05), the level of 0.5% significantly decreased liver TG content of broilers on day 21 and 42(P<0.05). 2) Abdominal fat percent were signi?cantly reduced in the broilers fed with 0.3% and 0.5% of HFCP than that of the control group(P<0.05). 3) Dietary supplementation of HFCP had no significantly effect on lipid content in thigh muscle, breast muscle and excreta of broilers(P>0.05). 4) Dietary supplementation with HFCP significantly increased propionic acid content(P<0.05), and decreased the rate of acetic acid and propionic acid in caecum of broilers(P<0.05). 5) According to the analysis of regression, the serum TG level, liver lipid content, and abdominal fat percent decreased quadratically(P<0.001) when the HFCP levels increased. 6) According to the analysis of correlation between variables, on day 21, propionic acid content in caecum was significantlynegative correlated with abdominal fat percent(r =- 0.988), the rate of acetic acid and propionic acid was significantly positive correlated with serum TG(r = 0.973) and abdominal fat percent(r = 0.977). On day 42, propionic acid content in caecum was significantly negative correlated with abdominal fat percent(r =- 0.995), the rate of acetic acid and propionic acid was significantly positive correlated with abdominal fat percent(r = 0.977). It could be concluded that dietary supplementation with HFCP could significantly reduce TG content in serum and liver, decrease abdominal fat deposition, improve lipid metabolism of broilers, and it might be through regulating the SCFA content and rate in the caecum of broilers.Through the study of the effects of HFCP on the content of cholesterol in the serum, liver,muscles, and excreta, and bile acids excretion of broilers, the results revealed that: 1) In different age stage(day 21 and 42), dietary supplementation of HFCP in the levels of 0.3% and0.5% significantly decreased serum total cholesterol(TC) and low density lipoprotein cholesterol(LDL-C) content(P<0.05), and significantly increased serum high density lipoprotein cholesterol(HDL-C) content of broilers compared to the control group(P<0.05). 2)Cholesterol levels of breast muscle, thigh muscle, and liver were signi?cantly reduced in the broilers fed with 0.3% and 0.5% of HFCP than those of the control group(P<0.05). 3)Compared with the control group, supplementation with HFCP in different levels significantly increased bile acid excretion in feces of broilers(P<0.05). 4) According to the analysis of regression, the serum TC level, cholesterol content in liver, breast muscle and thigh muscle decreased quadratically(P<0.01) when the HFCP levels increased. 5) According to the analysis of correlation between cholesterol deposition indexes and bile acids, on day 21, bile acids content of faeces was significantly negative correlated with cholesterol content in liver(r =-0.993) and thigh muscle(r =-0.994). On day 42, bile acids content of faeces was significantly negative correlated with cholesterol content in serum(r =-0.992), liver(r =-0.980), thigh muscle(r =-0.981), and breast muscle(r =-0.993). The results of this study suggest that the decreased content of cholesterol in serum, liver, and muscles of broilers may be caused by an increase in the fecal excretion of bile acids. 6) According to the analysis of correlation between cholesterol deposition indexes and SCFA, on day 21, propionic acid content in caecum was significantly negative correlated with cholesterol content in liver(r =- 0.971) and thigh muscle(r =- 0.991), the rate of acetic acid and propionic acid was significantly positive correlated with cholesterol content in serum(r = 0.968), liver(r = 0.999), and thigh muscle(r=0.966). On day 42, propionic acid content in caecum was significantly negative correlated with cholesterol content in serum(r =-0.951), liver(r =-0.966), and breast muscle(r =-0.995),the rate of acetic acid and propionic acid was significantly positive correlated with cholesterolcontent in serum(r = 0.990), liver(r = 0.996), thigh muscle(r =0.965), and breast muscle(r=0.994). The results of this study suggest that the decreased content of cholesterol in serum,liver, and muscles of broilers may be correlated with the SCFA content and rate in the caecum of broilers after HFCP fermentation.In order to give more information to clarify the mechanism of the lipid-lowering effects of HFCP, the gene expression of the key enzymes of fat synthesis, including Acetyl-CoA carboxylase(ACC) and fatty acid synthase(FAS), and the key enzyme of cholesterol synthesis,β-hydroxy-β-methyl-glutaric acid acyl coenzyme A reductase(HMGR), were studied in this research. The results revealed that: 1) On day 21, dietary supplementation with HFCP had no signi?cant effect on ACC mRNA expression in the liver of broilers(P>0.05). On day 42, dietary supplementation with different levels of HFCP significantly decreased the mRNA expression of ACC in the liver of broilers(P<0.05), and the expression level decreased quadratically(P<0.001)when the HFCP levels increased. 2)Both on day 21 and 42, compared with the control group,dietary supplementation with HFCP in 0.3% and 0.5% levels significantly decreased the mRNA expression of FAS(P<0.05), and 0.3% level significantly decreased the mRNA expression of HMGR in the liver of broilers(P<0.05), and the expression levels of FAS and HMGR decreased quadratically(P<0.01) when the HFCP levels increased. The results of this study suggest that dietary supplementation with HFCP could decrease the gene expression of ACC, FAS and HMGR, which are the key enzymes during the fat and cholesterol synthesis, might decrease the fat and cholesterol synthesis in the liver of broilers, and thus had the function of decreasing fat deposition and meat cholesterol content of broilers.The fermentation concentrate of Hericium caput-medusae(Bull.:Fr) Pers. without polysaccharides extracting process but in the doses of polysaccharides addition was added to the broilers diet in order to save additive cost, and the effects of HFC on lipid metabolism, growth performance, antioxidant status and meat quality of broilers were studied. The experimental animal and group situation were as follows: a total of 600 one-day-old Arbor Acres broilers were randomly divided into 5 dietary treatments(20 broilers per pen with 6 pens per treatment):control group(basal diet), ANT(basal diet supplemented with 5 mg flavomycin/kg diet), and three levels of HFC(basal diet supplemented with 0.56%, 1.67% and 2.78% of HFC). The experiment lasted for 42 d. Lipid metabolism and growth performance parameters were recorded on day 21 and 42, and all other parameters on day 42.Through the study of the effects of HFC on lipid metabolism, growth performance,digestibility, intestinal microbiology, and intestinal morphology of broilers, the results revealed that: 1) Dietary supplementation with HFC could significantly reduce blood lipid, and fat andcholesterol content in the meat of broilers(P<0.05). 2) The average daily feed intake was not affected by HFC inclusion during the entire experimental period(P>0.05). Incorporation of dried HFC in chicken diet improved the average daily gain compared with the control and ANT treatments, and the average daily gain increased quadratically(P<0.001) when the HFC levels increased. 3) In the small intestinal digesta and the caecum digesta, the Escherichia coli count decreased while the lactobacilli count and bi?dobacteria count increased quadratically(P<0.001)when the HFC levels increased. 4) The crude protein digestibility of broilers increased quadratically(P<0.001) when the HFC levels increased. 5) In the duodenum, jejunum, and ileum of broilers, the villus height and villus height to crypt depth ratio increased quadratically(P<0.001) when the HFC levels increased. These results demonstrate that dietary supplementation with HFC without plosacchrides extracting process could decrease fat and cholesterol deposition of broilers. Dietary supplementation with HFC increased gut lactobacilli and bifidobacteria counts and inhibited Escherichia coli growth, improved nutrient utilisation and intestine villus structure, and thus improved the growth of broilers.Through the study of the effects of HFC on antioxidant status and meat quality of broilers,the results showed that: 1) The superoxide dismutase(SOD), catalase(CAT) and glutathione peroxidase(GSH-Px) values increased quadratically(P<0.05), while the malondialdehyde(MDA) level in the serum, liver, and breast muscle of broilers decreased quadratically(P<0.001)with the increasing of dietary HFC level. 2) The pH24 h value of the breast muscle increased quadratically(P<0.001), while the drip loss and cooking loss decreased quadratically(P<0.01)when the HFC levels increased. 3) Dietary supplementation with HFC had no signi?cant effects on shear force of broilers(P>0.05). 4) The lightness(L*) value decreased quadratically(P<0.01), while the redness(a*) and yellowness(b*) values of the breast muscle increased quadratically(P<0.01) when the HFC levels increased. These results demonstrate that HFC has promising antioxidant potential to enhance oxidative status and meat quality in broilers.In conclusion, the polysaccharide content of different molecular mass components in HFCP was obvious different, and the highest content was in the range of less than 5000 D. The content and ratio of SCFA were changed and the gene expression of the key enzymes during the fat and cholesterol synthesis was decreased after HFCP fermentation in broilers caecum, and then the fat deposition and meat cholesterol content of broiler chickens were decreased. Dietary supplementation with HFC containing active ingredients, such as polysaccharide and polyphenol,could improve the lipid metabolism, regulate the intestinal microflora, improve the nutrient digestibility, enhance the antioxidant status, and improve the growth performance and meat quality of broilers. |
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