Study On The Effects Of Soy-Lecithin On Lipid Metabolism And Meat Quality In AA Broilers

This study was conducted to examine the effects of soy-lecithin on lipid metabolism and meat quality in broiler chickens.420 1-day-old Arbor Acres(AA) chicks were given a corn/soybean meal basal diet supplemented with different levels of soy-lecithin 0.0% (Cont.),0.5%(SL1),1.0%(SL2),2.0%(SL3) or basal diet with 2%soy-oil(SO);soy-oil and soy-lecithin mixture in proportion of 75/25(SOL1),50/50(SOL2) for 6 weeks.The growth performance,meat quality and related enzymes activities and gene expression of key enzymes and related hormones,as well as physiological and biochemical parameters were determined.The object of this study was to approach to the mechanism that soy-lecithin may possibly improve on carcass traits of broilers.1 Effects of soy-lecithin supplementation on growth performance, nutrient digestibility and digestive enzyme activities in broilersThe results showed that the body weight(BW) of broilers in SOL1 group was higher than the other groups in 42d(P＜0.05) and that the BW of broilers in SL2 was close to that in SO group.When calculated on the basis of entire experimental period(1-42d),growth performance of broilers in SL2,SOL1 and SOL2 group increased significantly compared with their control counterparts(P＜0.05).The relative weight of liver was increased by feeding with 2%soy-lecithin.The results of digestibility experiment showed that the utilization of dry matter(DM),crude protein(CP) and ether extract(EE) were improved in SL2 and SOL1 group from 19 to 21d.During 39-41d,apparent metabolizable energy(AME) in the groups supplemented with soy-lecithin and soy-oil was higher than the control group. The utilization of EE in SL3 group was higher than the control group(P＜0.05),but no significant effects were observed in the utilization of EE in SO,SOL1,SOL2 and SL3 group(P＞0.05).The growth performance and utilization of nutrients decreased in SL3 group.The activity of maltase in anterior intestinal in soy-lecithin supplemented groups and 2%soy-oil group was higher than the control group(P＜0.05).It is suggested that lecithin exerted a dose dependent manner on the growth performance of broilers.Basal diets supplemented with 1%soy-lecithin and soy-lecithin/soy-oil in a proportion of 25/75 exerted a positive effect on the growth performance during the overall period and improved nutrients digestibility in broilers.2 Effects of soy-lecithin on the body fat distribution and meat quality in broilersThis study was conducted to examine the effects of soy-lecithin on body fat distribution,meat eating quality,muscle fatty acid composition,cholesterol levels and tissue oxidation stability in broiler chickens.The results showed that the percentage of thigh muscle fat was improved when 1%soy-lecithin was supplented to the diets of broilers (P＜0.05).SL3 group had the lowest abdominal fat pad weight.PH value(24h),drip loss (48h) and cooking loss were lower in the groups supplented with soy-lecithin and soy-oil compared with the control group.An increasing tendency was found in red color of breast muscle in soy-lecithin contained diets(P=0.072 between Cont.and SL2).The content of linoleic acid(C18:2),linolenic acid(C18:3) and polyunsaturated fatty acid(PUFA) were increased in the muscle of broilers fed with soy-lecithin.No statistical differences were observed in tissue MDA and cholesteral levies in different treatment groups(P＞0.05).No significant differences were observed among SO,SOL1,SOL2 and SL3 groups when concerned with the eating quality and PUFA content of breast and thigh muscle(P＞0.05). The results of the present experiment implied that soy-lecithin has body fat redistribution capacity,and it can increase unsaturated fatty acid levels and improve the meat qulity in broiler chickens.Soy-lecithin can replace soy-oil supplemented in the diet of broilers and do no negative effects on the quality and fatty acid profiles of chicken.3 Effects of soy-lecithin on serum lipoprotein profiles,lipid metabolism related hormones and antioxidation capacities in broilerThe purpose of this experiment was to determine the effects of soy-lecithin on the serum antioxidation competence,lipoprotein profile and hormones involving in lipid metabolism of broilers.The results showed that serum concentration of total serum cholesterol(TC) and low-density lipoprotein cholesterol(LDL-C) were reduced by soy-lecithin(P＜0.1),whereas high-density lipoprotein cholesterol(HDL-C) had an improving tendency(P＜0.06).Serum apoA levels in the control group was higher than SL2 group(P＜0.05),but had no significant differce compared with the other groups(P＞0.05). Insulin(INS) were elevated in SL3 group compared with control group(P＜0.05).Serum MDA levels were reduced when 1%soy-lecithin were supplented to the diets of broilers (P＜0.05).No significant difference was observed in the activity of SOD.The results indicate that soy-lecithin has cholesterol lowering capacity and that soy-lecithin can improve serum lipoprotein profiles.The antioxidation capacity of soy-lecithin may be related to its emulsification ability and that it can improve the composition of cell membrane.4 Effects of soy-lecithin on activity of lipid metabolic enzymes and expression of genes in broilerThe purpose of this experiment was to determine the effects of soy-lecithin on the activity of lipid metabolic enzymes and lipogenic genes expression in the liver of broiler chickens.At the end of the experiment,samples of serum and liver tissues were taken for analyses of the activity of lipid metabolic enzymes and the expression of selected genes. The hepatic expression of the genes encoding malic enzyme(ME),fatty acid synthase (FAS),acetyl-CoA carboxylase(ACC) and 3-hydroxy-3-methylylutaryl-Coenzyme A reductase(HMG-CoAR) were determined with reverse transcription-polymerase chain reaction(RT-PCR) using SYBR green as a flourophore monitored in a real time mode.The results showed that the activity of serum lipoprotein lipase(LPL) and hepatic lipase(HL) were improved when soy-lecithin were involved in the diets(P＜0.05),but no significant differenc were observed in the activity of serum HL and total lipase(P＞0.05).The abundance of ME,FAS,ACC and HMG-CoAR mRNA were increased with the increasing level of soy-lecithin.The results indicate that soy-lecithin alters the activity of enzymes and that the regulation of fat metabolism in AA broilers is not simply through suppression of hepatic lipogenic gene expression.