Effects Of Dietary Different Levels Of Pollen On The Fatty Acid Composition In Egg Yolk And Study On The Inhibition Of Obesity On Cell Level In Vitro

The experiment was conducted to investigate the effects of dietary differentlevels of rape pollen on the fatty acid composition in egg yolk and tissue of layinghens.540 healthy Hy-Line variety brown hens which were in egg-laying peak and atthe same time were randomly allotted to four dietary treatments, supplying with0%(group A)、3%(group B)、5%(group C) and 8%(group D) rape pollen in basal dietrespectively. The experiment lasted for 70 days including two phases, the first phase(0~50d) fed with basal diet and rape pollen and the second phase (51~70d) only fedwith basal diet respectively.During the period of pollen added,the daily feed intake、the laying rate、theaverage egg weight、the average daily egg yield and feed/egg of group B and group Chad no significant difference with group A(P＞0.05), The diet containing 3% and 5%of rape pollen showed no adverse effects on the performance of laying hens.Compared to the control group,the diet containing 8% of rape pollen had nosignificant effect on the daily feed intake and the average egg weight, the layingrate(P=0.009＜0.01) and the average daily egg yield(P＜0.05) decreased significantly,feed/egg increased significantly(P＜0.05), but the average egg weight of eachexperimental group tended to rise compared to the control group.After stoppingfeeding pollen,the ratio of feed/egg reduced to the control group level.In the first stage (0~50d), the contents ofω-3PUFA (ω-3 polyunsaturated fattyacid)、ALA (α-linolenic acid)、DHA(docosahexaenoic acid) in egg yolk increasedwith the increasing of dietary rape pollen,whereas the ratio ofω-6/ω-3PUFA wasexact opposite and group D had significant difference from 5d to 30d (P＜0.01 vs group A). The contents ofω-3PUFA、ALA、DHA in egg yolk and the ratio ofω-6/ω-3PUFA returned to its original level in the second stage(51~70d). Dietarydifferent levels of rape pollen had no effect on the fatty acid composition in brain(P＞0.05). The contents ofω-3PUFA in breast meat decreased with the increasing ofdietary rape pollen. The contents ofω-3PUFA in chicken liver were 1.96%、1.89%、3.11% and 3.28% respectively. Group D increased extreme significantly(P＜0.01 vsgroup A). While the contents ofω-3PUFA in adipose tissue were 1.61%、1.84%、1.86% and 2.27% respectively. Group D increased significantly(P＜0.05 vs group A).These data suggested that dietary rape pollen could increase the content ofω-3PUFAin egg yolk, liver and adipose tissue. The diet containing 8% of rape pollen showedthe best effects among three dosages.The content of MDA in egg yolk of group B and group C had no significantdifference(P＞0.05) with group A(except group B on the fifteenth day). During theperiod of pollen added, the content of MDA in egg yolk of group D was higher thanthe control and there were significant difference on day 15th(P=0.014＜0.05 vs groupA) and day 20th(P=0.010＜0.05 vs group A).After stopping feeding pollen,the contentof MDA in egg yolk of group D was lower than the control on day 60th.The content of rape pollen in diet is not the more the better,in this study, the dietcontaining 8% of rape pollen affected the performance of laying hensadversely.During the period of pollen added,the content of MDA in egg yolk wasobviously higher than the content of MDA in egg yolk of group A, and there weresignificant differences on day 15th and day 20th(P＜0.05).In vitro study on the cell level showed that the aqueous extract(250μg/mL and125μg/mL)of pine pollen had an significant adverse effect on the differentiation of3T3-L1 preadipocyte(P＜0.05) and the inhibitory rate was 36.36%.The alcoholicextract of pine pollen could stimulate the differentiation of 3T3-L1 preadipocytesignificantly(50μg/mL, P＜0.01; 12.5μg/mL和3.125μg/mL, P＜0.05).The results suggested that:(1) The diet containing 3% and 5% of rape pollenshowed no effects on the performance of laying hens, but 8% of rape pollen affectedthe performance of laying hens adversely.(2) Dietary rape pollen could increase the content ofω-3PUFA in egg yolk, the diet containing 8% of rape pollen could increasethe content ofω-3PUFA in liver and adipose tissue significantly and promoted thelevel of MDA in egg yolk obviously.(3)The aqueous extract of pine pollen had ansignificant adverse effect on the differentiation of 3T3-L1 preadipocyte while thealcoholic extract of pine pollen could stimulate the differentiation of 3T3-L1preadipocyte significantly.