Effects Of Betaine,DL-methionine On Growth Performance And Carcass Compositon Of Table Duck And Approach To The Mechanism

The present study was conducted with meat duks to determine the effects of 2 levels of betaine (0, 500mg/kg) and 3 levels of methionine(0, 600mg/kg , 1200mg/kg) on growth performance, carcass composition ,and the interactions between betaine and methionine in a methionie-deficient diet, and approached the mechanism by determing the activities of betaine -homocysteine S-methyltransferase (BHMT) and the contents of carnitine . The basic diet contained 3.5g methionine/kg( 1-21 days), 3.0g methionine /kg (22-41 days ).Eight hundred and sixty four Cherry Valley Ducks were randomly divided into six groups , each of which included six replicates of tweaty four ducks . The total ducks were fed one of six diets in a 2 (0 and 0.5 gbetaine/kg) X 3 (0, 600mg, 1200mgDL-methionine/kg) factorial arrangement . The period of the test was 41 days and performance was determined at 21 and 41 days. During this period , feeding intake ,death percent ,body weight were written down.After feeding trials ,54 ducks (six replicates which were consisted of 9 ducks each) were randomly picked out for slaughter determining. At the same time ,liver ,breast and serum samples were taken for laboratory analysis. Contents of free carnitine , acid-insoluble carnitine in breast; activities of BHMT in liver were determined.The result of feeding trail showed that, in the earlier stage: (1) betaine treated groups singnificantly increased the weight of the earlier stage and decreased the feed:gain ratio (P<0.01) . In contrast to the control group, 500mg/kg betaine only treated groups increased weight at 21 days by 3.96 % (PO.05 ), feed: gain ratio by 7.13 % (P<0.05). (2 ) methionine treated groups also obviously increased weight and decreased feed: gain ratio(PO.01) .In contrast to the control group, 600mg/kg, 1200mg/kg DL-methionine treated groups increased weight at 21 days by 2.90%(P>0.05X 6.9% (PO.01) ,feed:gain ratio by 2.0% (P>0.05)> 6.15 % (PO.01) . (3)There no significant difference between the effects of 500mg/kg betaine and the effects of 1200mg/kg methionine on body weight and feed:gain ratio.In the later stage : (l)in contrast to the controul group ,betaine treated49groups has no singnificant effect on both the weight and the feed:gain ratio(P>0.05) . (2)methionine treated groups increased the weight at 41 daysobviously (PO.05) , but had no significant effect on the feed:gain ratio(P>0.05 ) .(3) There no obvious difference between the effects of500mg/kg betaine and the effects of 1200mg/kg methionine on body weightand feed:gain ratio.The results of slaughter trial showed as follows : (1) Betaine treated groups significantly increased the breast yield (PO.01) and decreased the percent abdominal fat (P<0.01) . In contrast to the controul group, 500mg/kg betaine increased the breast yield by 5.36%(P<0.01), decreased the percent abdominal fat by 10.65 % (P<0.05).(2) methionine supplementation also significantly increased the ducks' breast yield (P<0.01) ,but had no significant effects on percent abdominal fat (P>0.05) .In contrast to the controul group , the 1200mg/kg methionine increased the breast yield by 6.46% (P<0.01) . (3)There was no obvious effect of both betaine and methionine on carcass yield (P>0.05 ) . (4)In terms of breast yield and percent abdominal fat, there were consistent effects of 500mg/kg betaine and 1200mg/kg methionine .The anaylsised activities of BHMT indicated that : (1) the betaine treated groups obviously improved the total and specific activities of BHMT (PO.01) . In contrast to the control group , treat groups supplemented with 500mg/kg betaine respectively increased the total50activities of BHMT by 44.76 % (P<0.01) , increased the specific activities of BHMT by 47.54% (P<0.01) . (2) Treat groups supplemented with 600 mg/kg and 1200 mg/kg betaine respectively increased the total activity of BHMT and the specific activity of BHMT, yet had no obvious difference in contrast to the controul group .(3) Treat groups of 500mg/kg betaine increased the total activities of BHMT by 40.