Effects Of EGCG On Lipid Metabolism And Its Related Gene Expression In Broiler Chickens

In past decades, poultry breeding industry have got a rapid development to meet the consumption demand, but chicken containing higher fats was also a pressing problem at the same time. The traditional breeding method takes much time, thus feed regulation is an essential way to settle the problem. Some researchers have reported that fed added with green tea could improve the chicken meat quality. Under this background, we surveyed the effect of EGCG (the main monomer composition among tea catechins) on lipid metabolism of broilers in its middle-late growth period, simultaneously with its underlying mechanism in this study. The researches in this paper could provide exact theoretical to promote the popularization and the application of green tea in poultry animals fed.Seventy-two 28 days male broilers were subjected to three EGCG oral injection concentration treatment:0 mg/kg body weight (NC),40 mg/kg body weight (L-EGCG),80 mg/kg body weight (H-EGCG). Samples collected at weeks 2 and weeks 4 of the orally experiment respectively. To study the effects of EGGC on fat metabolism in chickens, serum parameters, fat deposition levels, hepatic fatty acid composition, expression of genes related to lipid metabolism in liver and abdominal adipose tissues, and activities of hepatic fatty acid metabolism enzymes were investigated in chickens, the primary results of this research as follows:(1) With EGCG treatment for 2 weeks, no significant differences in serum lipid parameters and fat deposition indicators of broilers were observed among different group broilers. After 4 weeks, compared with NC group birds, the 40mg dose of EGCG supplementation decreased the serum TG by 45%, and increased FFA by 39%; the 80mg dose of EGCG supplementation decreased the serum levels of TG (48%) and LDL-c (22%), moreover serum contents of HDL-c and FFA were increased by 20% and 52%; P<0.05, respectively. Two doses of EGCG supplementation significantly reduced the fat deposition in broilers compared with that of NC group after 4 weeks, these indicators as:the abdominal fat rate was reduced by more than 30%, intramuscular fat thickness was reduced by more than 25%, subcutaneous fat thickness and hepatic fat rate were reduced by about 10%, P<0.05, respectively. The results showed the anti-obesity of EGCG in broilers, and it suggested the time effect of EGCG on body lipid parameters in chicken was no less than 2 weeks for our dose of EGCG. In our study, it indicated that EGCG supplement had no negative influence on the growth of broilers.(2) The fatty acids composition in the liver was determined after broilers supplement with EGCG for 2 and 4 weeks, results suggested that green tea EGCG could significantly increase the polyunsaturated fatty acids ratio (about 15% in both dose groups birds) in broilers compared with NC group, such functional fatty acids as ARA、DHA and DPA, this might make contributions to improve the nutritional value of chicken.(3) Our results suggested that EGCG could down-regulate the mRNA levels of hepatic lipid anabolism genes FAS (44%), SCD (73%), SREBP (56%), and reduced the activities of hepatic fatty acid synthesis enzymes ACC (17%), FAS (44%); EGCG could up-regulate the expression of fat catabolism related genes CPT-1 (2.31 fold), ACOX (3.38 fold), PPARα (1.49 fold), and increased the activity of fatty acid catabolism enzyme CPT-1 (4.7 fold); EGCG up-regulated the expression of fat hydrolysis gene ATGL (1.6 fold) and reduced fat deposition by inhibiting the expression of LPL (25%) in abdominal fat tissue; P<0.05, respectively. Our study suggested that the lipid-lowering effects of EGCG in broiler chickens were partly by inhibiting the lipogenesis, simultaneously promoting lipolysis and fat oxidation in broiler chickens.