| Feed contributes to over 70% of the production costs in the poultry industry.Increasing feed costs and environmental issues of husbandry prompted geneticists to include feed efficiency as selection goals in breeding.In this study,genetic parameter related to the feed conversion of Pekin duck was conduct with the AI-REML method using an animal model,and to reveal the genetic relationship between RFI traits and other important economic traits,which provided the basis for breeding of Pekin ducks.The RFI traits of four pekin duck strains were selected for five consecutive generations.The feed conversion and lean meat percentage of each line were significantly increased,and the sebum percentage was significantly reduced.The iTRAQ technique was used to analyze the proteome expression differences of Pekin duck's live,pectoral muscle and sebum after bidirectional selection of RFI traits.The results were summarized as followings:1.The heritability of Pekin duck body weight at 14 day(BW14),body weight at 42 day(BW42),feed intake(FI),feed conversion ratio(FCR),chest width(CW),kell long(KL),breast muscle thick(BMT),breast muscle volumev(BMV),residual feed intake(RFI)and average daily gain(ADG)were between 0.298 to 0.414,it belongs to medium heritability.The heritability of RFI,FCR and FI traits were 0.41,0.38 and 0.327,respectively.RFI traits were positively genetic correlation with FCR(0.655)and FI(0.626);negatively genetic correlation with CW,KL,BMT,BMV,GW and ADG(-0.588~-0.286);and were not significantly genetic correlation to BW42(-0.077).The FCR was negatively genetic correlation with all economically relevant traits except RFI and FI.In the high-RFI strain Pekin duck,the sebum weight,abdominal fat weight,and sebum rate were significantly higher than the low-RFI strain Pekin duck.The pectoral muscle weight and feed conversion efficiency were significantly lower than the low-RFI strain Pekin duck.This shows that the RFI trait can be used as the target trait for the selection of feed conversion efficiency in Pekin duck.2.The RFI traits of four pekin duck strains were selected for five consecutive generations.The feed conversion efficiency and lean meat percentage of each line were significantly increased,and the sebum rate was significantly reduced.The feed conversion of the four lines(A,B,C and D)decreased by 0.23,0.26,0.15,and 0.17 respectively.The breast muscle weight gain up to 201.7g of line B;the leg muscle weight gain up 53.4 on line C;the breast muscle rate gain up to 4.64 percentage points on line B;the leg muscle rate gain up to 3.34 percentage points;the sebum rate decline to 9.07 percentage points.3.Proteomic analysis showed that compared with the high RFI strains,there were 25 high-expressed proteins and 9 low-expressed proteins in the liver of low-RFI strains;34 high-expressed proteins and 21 low-expressed proteins in the breast muscle of low RFI strains;34 highly expressed proteins and 25 low expressed proteins in sebum of low RFI strains.The results of bioinformatics analysis showed that the differential proteins in the liver mainly participate in the processes of glucose metabolism and stress response;the differential proteins in the pectoral muscles mainly participate in biological processes such as muscle development and oxidative stress;the differential proteins in sebum are mainly involved in the biological processes such as fatty acid synthesis,metabolism and stress response.4.The high expression of the heat shock protein family in the low RFI strain reduced the stress response then improved the feed conversion efficiency;the high expression of fatty acid synthesis-related proteins in high RFI stain preliminarily revealed the molecular mechanism of high fat deposition ability in high RFI strain;the high expression of muscle development and anti-stress proteins in the breast muscle of low RFI strains provides direction for us to reveal the mechanism of high breast muscle rate in this strain. |
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