Comparison On Development And Nutrient Contents Of Muscle In Meat-type Ducks At Different Ages

With the improving of living standard,meat products with special flavor and delicious taste are becoming increasingly popular.Generally,a number of factors have influences on the quality of meat products,such as the breed,the raising environment or mode,the fodder nutrition level and so on,especially,the marketing age also plays a pivotal role in affecting the meat quality.It has been shown that flavor molecules such as amino acids in vivo change gradually along with the increasing age,resulting in the change of meat quality.However,due to the lack of relevant research on meat-type ducks,the marketing age of ducks appears different as well as the quality of meat products.In this study,Cherry Valley ducks and White Kiaya ducks were selected to investigate development and nutrient contents of muscle at different ages,which provided reference for determining reasonable marketing age and product grading of fast-growing meat-type duck and high-quality meat-type duck.The main results are as follows:1.Effects of the different ages on the growth and development of Cherry Valley ducks'muscle:We detected the growth and development of muscle and muscle fibers of Cherry Valley ducks at different ages,including 28 days,38 days,42 days and 45 days of ages.The results revealed that the weight gain rate of Cherry Valley duck obviously decended after 38 days old,and the breast muscle and leg muscle weight also showed a similar trend.What's more,the muscle fiber area became thicker obviously at early age.The breast muscle and leg muscle fiber area of Cherry Valley duck at 38-day age were 791.48 ?m2 and 3180.76 ?m2,respectively.While the development of leg muscle fiber began to decline with the increasing age,and the development of breast muscle also dropped after 42 days.Moreover,the expression of genes related to muscle development at different ages showed that the highest expression of PPAR-?and MyoD appeared in breast muscle at 38 days old and in leg muscle 42 days old,repectively.While the highest expression of MSTN appeared in breast muscle at 45 days old and in leg muscle at 42 days old,repectively.These results suggested that the best age of growth and development and muscle fiber were from 38 to 42 days in Cherry Valley duck,while the duck of 45 days old slowed down in the growth and development of muscle and muscle fiber slowed down.2.Effects of the different ages on nutrient deposition in Cherry Valley ducks' muscle:The contents of nonnal nutrition composition,metal element contents,amino acid contents and fatty acid were detected in Cherry Valley ducks,muscle at different ages,including 28 days,38 days,42 days and 45 days of ages.The results showed that the protein content in breast muscle was 22.62%at the 38 days old,which was significantly higher than the other 3 periods(P<0.05),while the fatty contents reached to the lowest level at the 42 days old.The contents of Fe,Mg,P,K reached to the highest level in breast muscle at 38 days old,while the Ca,Zn were highest at 28 days old.The content of the essential amino acids such as threonine,valine,isoleucine,leucine,phenylalanine,lysine and the flavor amino acids such as alanine,serine,glycine,proline,glutamic acid reached the highest value at the 38 days old,among which the content of glutamic acid in muscle reached 33.72 g/kg.In addition,the contents of arachidonic acid,DHA and polyunsaturated acid in breast muscle reached the highest value at the age of 38 days,while octadecanoic acids and saturated acid reached the highest level at 42 days of age.Above all,the great majority of indexes of nutrition composition suggested that 38-42 days of ages were the preferential day at which nutrient deposition in muscle was the best.3.Effects of the different ages on the growth and development of small-sized meat ducks' muscle:The growth and development of muscle and muscle fibers were detected in White Kiaya ducks and Putian black ducks at different ages,including 42 days,49 days,and 56 days of ages.The results showed that White Kiaya ducks grew faster than Putian black ducks at early ages,the weight gain of breast muscle and leg muscle slowed down during 49 to 56 days of age.What's more,the growth and development trend of White Kiaya duck was similar to Putian black duck.,The breast muscle and leg muscle fiber areas decreased gradually during 49 to 56 days of age.Additionally,the expression of genes related to muscle growth and development showed that PPAR-a and MSTN in breast muscle and leg muscle of White Kiaya duck reached the highest value at the 56 days old,and the expression of MyoD in leg muscle reached the highest value at the same time.These results suggested that the growth and muscle fiber development of White Kiaya duck at early ages were fast but slowed down after 49 days old.4.Effects of the different ages on nutrient deposition in small-sized meat ducks' muscle:The contents of nutrition composition,metal element,amino acid and fatty acid were detected in White Kiaya ducks and Putian black ducks' muscle at different ages,including 42 days,49 days and 56 days of ages.The results showed that the protein and metal element deposition showed a similar trend between White Kiaya ducks and Putian black ducks.The protein content in White Kiaya ducks' breast muscle reached the highest value at the 56 days old(P<0.05);the content of Fe,Cu,Ca,Mg,P,K in breast muscle reached the highest level at 56 days old.However,fatty acid deposition in White Kiaya ducks and Putian black ducks' muscle showed an opposite trend,and muscle fat of White Kiaya ducks improed with the age increasing.The essential amino acids including threonine,proline,isoleucine,methionine and the flavor amino including glutamic acid,serine and alanine did not fluctuated significantly with the increase of age.The unsaturated fatty acids in the breast muscles of White Kiaya ducks had higher levels of enrichment at 49 or 56 days of age,while the unsaturated fatty acids in the leg muscles of Putian black ducks is higher at 42 or 56 days of age.From the above,it concluded that,the content of protein,metal elements such as Ca,Mg,P,K,and unsaturated fatty acid content improved with the age prolong for small-sized ducks,,but the deposition of muscle amino acid was not significantly improved.This result also clarifies that not all muscle nutrients are gradually transformed and accumulated as the age increases.In summary,the muscle growth and muscle fiber development are optimal at 38-42 days old for the large-sized meat duck(cherry valley duck),and the content of muscle protein,Fe,Mg,P,K flavor amino acids such as alanine,tyrosine,glycine,and glutamic acid,as well as arachidonic acid,DHA,and polyunsaturated fatty acids reached their peaks during this period.it was recommended that it should be on the market at 38-42 days old.For small-sized meat ducks,early growth and muscle fiber development were faster.the content of protein,Ca,Mg,P,K,unsaturated fatty acids reached the peak at the age of 56 days.It is recommended that it should be on the market at the 56 days old.In light of the smaller body weight of the Putian black ducks at the 56 days of age,the day to market may be appropriately delayed.