| This thesis consisted of two experiments, Exp.1studied growth performance, carcass quality and nutrients availability between male Maple Leaf Duck (MLD) and Cherry Valley Duck (CVD). Exp.2was conducted to comparatively study intestinal digestive physiology, blood chemistry between MLD and CVD during day1to35.Exp.l Comparison of growth performance, carcass composition and nutrients utilization between MLD and CVD2801-d-old MLD and2801-d-old CVD were randomly allocated in28replicates(10ducklings/replicate), respectively. All ducks were reared under the same environmental conditions. Water and feed were provided ad libitum throughout the experiment. The results showed as follows:(1) Absolute growth rate and1-14d relative growth rate of MLD were significantly higher than that of CVD (P<0.05); MLD exhibited superior (P<0.01) body weight up to35days of age, and reached2,905.75g.(2) ADFI of MLD was significantly less (P<0.01) during d15to35and the whole experiment, and feed:gain (F/G) was significantly lower (P<0.01) than CVD in each phases, F/G of MLD and CVD were1.52and1.72during the whole experiment, respectively.(3) The4th feather length was not difference between two kinds of ducks at age of35d, but there were significantly difference for the score of back with the higher score for MLD than CVD (P<0.01).(4) For MLD, eviscerated carcass weight and yield were higher than CVD (P<0.01), and breast yield was highly significant (P<0.01), but abdominal fat was much lower than CVD (P<0.01).(5) MLD had lower protein content (P<0.01), higher drop loss(P<0.01) of breast muscle than CVD’s.(6) Dietary AME for MLD was significantly lower (P<0.01) than that for CVD, but dietary AMEn was no difference (P>0.05) between MLD and CVD, were3.53kcal/g and3.57kcal/g, respectively.(7) MLD exhibited superior dietary amino acids ileal digestibility, except Leu, Phe, Tyr (P<0.05).Exp.2Comparison of intestinal digestive physiology between MLD and CVD401-d-old MLD and401-d-old CVD were randomly allocated in5replicates (8ducklings/replicate), respectively. Diet and management was the same with Exp.1. The results showed as follows:(1) BW of MLD were significant heavier (P<0.01) than that of CVD per week. Using Gompertz and Logistic models to fit BW of MLD and CVD by per week, two duck lines had a similar growth curve, the inflection point of age was a little earlier, and the inflection point of weight of MLD was a little heavier than those of CVD.(2) There was a similar development pattern of digestive organs of two lines with age. Relative weight of each intestinal segments and pancreas of MLD and CVD gained the maximum at7d of age, whereas relative weight of liver, proventriculus, gizzard and relative length of each intestinal segments existed the maximum at1-d-old, after that the numerical values drop gradually with age.(3) The relative weight of digestive organs and relative length of intestinal segments in MLD were significantly lower than those in CVD (P<0.01).(4) The villus height and the ratio of villus height to crypt depth in duodenum of MLD were higher than those of CVD.(5) PepT1and CAT2mRNA expression in duodenum and jejunum were higher than those in ileum, and their expression had the peak on14-d-old; Compared with duodenum and jejunum, ileum PepT1, CAT1,CAT2mRNA expression pattern were different. CAT1(P=0.086), CAT2(P=0.059), PepT1(P<0.05) mRNA expression in ileum of MLD had lower than those of CVD.(6) The change pattern of serum GLU, TC, HDL, TG, URE concentration of MLD and CVD with age were similar; Serum GLU raised first and then dropped, TC and HDL decreased gradually, TG increased gradually, and URE decreased to28-day-old and then raised back. Serum TC and TG concentration in MLD were significantly lower (P<0.05) than those in CVD. In conclusion, the combination of digestive organs (weight) and intestinal growth (weight and length) and maturation (villus height) allowed MLD to achieve a higher growth rate, feed conversion efficiency and dietary amino acid utilization. |
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