| The aim of this study was to test the effect of early feeding and exogenous putrescine on bodyweight, muscle weight and some parameters of the development of jejunum of ducks, and investigate the relationship among the development of GIT, muscle weight and bodyweight. The result will provid a theory for feeding duck with high coefficient of performance and healthy. The trial was in 2×2 factorial experimental design. Two hundred and ninety eight Cherry Valley Ducks were obtained from a commercial hatchery 0-3h posthatch as experimental animals for our study. First of all, ten ducks were selected randomly and slaughtered to get the samples. Then, the rest were distributed equally into four treatments according to weight and each treatment contains 8 replicates and 9 ducks in each. The control treament (C) contained ducklings which were held for 48h without access to feed. In treatmentⅡ(T1), the Ducks were provided water and feeds 48h later posthatch and diet supplemented with 0.25% putrescine. Ducks in TreatmentⅢ(T2) were provided water immediately and were fed in 6h posthatch. In treatmentⅣ(T3), the ducks were provided water and feeds 6h later posthatch and diet supplemented with 0.25% putrescine. In treatmentsⅡandⅣ, the time of additive exogenous putrescine was from 0d to 7d post-hatch, after 7d, all the experimental animals were fed control diet. The whole experimental stage lasted 35 days. We got the samples on day 0, 2, 4, 7, 15, 25 and 35 posthatch, the samples included yolks, breast mucsle, thigh mucsle, liver and intestine. We determined the weight of them and then tested the concerntration of liver on day0 , 2 and 4. Then we determined disaccharidase activity, the concerntration of DNA and protein in one week posthatch, respectively, finally, the morphometric analysis was undertook. The results of this study were as follows:Part 1 Effect of early and exogenous putrescine on growth performance, energy status and weight of muscle of ducks1,During 48 h posthatch early feeding can significantly improve the bodyweight of ducks, early feeding improve the BW about 10%, and delay access to feed decrease the BW about 24%. On day 7 and 35, early improved the BW about 25.8% and 5.2%, respectively. This indicated that early feeding can affect the BW on day 7 and then effect the BW on day 35. There were no significantly effect on BW when diet was supplemented with 0.25% putrescine (P>0.05) .2,On day 0, the weight of residuary yolk was 6.2g. It decreased and was less than 0.3g on fourth day after hatch, there was a noticeable tendency earling feeding promoted the absorption of residuary yolk of ducks (P=0.0571), this may be beneficial for the development of intestine. Dietary putrescine can not impact the weight of residuary yolk of ducklings after hatch.3,On day 0, the concertration of the liver glycogen was 246.24 mg/100g, total liver glycogen was 3.36 mg . On day 2, The liver glycogen concentration of early feeding ducks was 3234.72 mg/100g , however , delay access to feed decreased this and value, it was 134.05 mg/100g. At the same time total liver glycogen of early feeding were significantly higher (P<0.01) than ducklings which were held for 48h without access to feed, and there were no significantly effect on them when added exogenous putrescine.4,Early feeding can significantly improve 7.2% of the relative weight of breast muscle on day 2(P<0.01), and aslo can significantly improve the relative weight of breast muscle on day 25 and day 35, the data were 7.7%和13.1%, respectively. There was no effect on the relative weight of thigh muscle (P>0.05) . Exogenous putrescine can not impact the relative weight of breast muscle , but can significantly decreased the relative weight of thigh muscle on day 25 and day 35, the values were 5.2% and 9.5%, respectively.Part 2 Effect of early and exogenous putrescine on development of intestine of ducks1,Early feeding can markly improve the development of the small intestine of meat ducks in one week after hatch. Because early feeding can significantly enhance the mass and 12.5% of the lengh of the small intestine (P<0.05 or P<0.01), and improve the activity of maltase on day 4 (P<0.01) and sucrase on day 2 and day 4 of jejunum, respectively. This suggested that early feeding can improve the digestion of carbohydrate. Early feeding aslo can raise the villus height on 2d, 4d and 7d (P<0.01), respectively, and depress the crypt depth on 2d and 7d (P<0.05 or P<0.01), respectively. This suggested that early feeding can improve the absorption of nutrient. Finally, Early feeding significantly improved the protein concentration of jejunum on day 4 and day 7 posthatch (P<0.05 or P<0.01), respectively, significantly improved the total DNA of jejunum 0-7d posthatch (P<0.05 or P<0.01).2,Under the condition of our experiment, exogenous putrescine maybe retard the development of the small intestine. Because dietary putrescine significantly decreased the weight of jejunum on day 4 (P<0.01) and decreased the weight of ileum on day 4 and 7 (P <0.05), respectively, and aslo significantly decreased about 3.3% of the lengh of them(P<0.05 or P <0.01). At the same time, exogenous putrescine significantly depressed the activity of maltase on day 4 (P<0.05) although increased the activity of maltase and sucrase afterwards. The final, diet supplemented with 0.25% putrescine degraded the protein concentration of jejunum on day 4 (P<0.05) and had the tendency of improving the crypt depth on day 7 (P=0.0775). These data indicated that: (1) Early feeding can improve the absorption of yolks and enhance the status of liver , then decrease the weight loss of pectoralis muscle. At the same time, early feeding can improve the volume of enterocyte, subsequently increase the height of intestinal villus and the mass and length of intestine. Thus, it's beneficial for the digestion and absorption of nutrient, and then improve the weight of ducks. (2) Diet supplemented with 0.25% putrescine could not accelerate the speed of the development of small intestine, and it had no significantly effect on growth performance of Cherry Valley Ducks, the result didn't support our hypothesis.
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