دانلود رایگان مقاله توسعه سیلیکون T شکل کانولا برای گوارش روده ای ساده در اردک

Abstract

An experiment was conducted to develop and evaluate a T-shaped cannula for sampling intestinal digesta of ducks. Forty intestinal-cannulated drakes were selected to evaluate the survival rate for the cannulated ducks and body weight (BW) recovery after cannulation. After a recovery period of 30 days, 24 cannulated drakes and 24 intact drakes were selected by BW and divided into 8 replicates with 3 ducks per replication. The corn-soybean based diet 1 with a high metabolizable energy (ME) content and diet 2 with a low ME content were used to compare the digestible ability of cannulated drakes to intact drakes. Energy balance assays consisting of periods 1 (8 days), 2 (22 days) and 3 (22 days) were to determine the endogenous energy loss in 2 groups of ducks, and to determine the ME for the diets 1 and 2 with each using the same 2 groups of ducks, respectively. No significant difference was observed in the BW of the cannulated ducks on day 15 vs. day 0 after the surgical operation. The survival rate for the cannulated ducks was 75% on day 60 after the operation. In the energy balance assay, the BW loss of cannulated ducks was greater (P < 0.05) than that of intact ducks in the period 1, however, no significant difference of BW loss was observed between cannulated and intact ducks in the remaining 2 periods. Endogenous energy loss in the period 1, and the ME of diet 1 in the period 2 were not different between cannulated and intact ducks. However, in the period 3, less (P < 0.01) ME of diet 2 was observed in cannulated ducks than intact ducks. It indicated the cannulated ducks can be used for a period from 30 to 60 days after the cannulation.

3. Results and discussion

BW of cannulated ducks on day 15 after surgical operation were not significantly different from these of ducks before the operation (3612 ± 263 g vs. 3639 ± 298 g, P > 0.05) (Table 2). This result indicated that the BW of ducks can recover from the cannulation operation after 15 days. The estimate of 15 days was similar to estimates of 8–21 days for broilers reported by others (Van Leeuwen et al., 2000; Manangi et al., 2007). Of the 40 cannulated ducks, the cannula pulled out of the body wall in 8 ducks, and lameness was occurred in 2 ducks. The survival rate for the cannulated ducks was 75% on day 60 after the operation, which was greater than that reported by Gurnsey et al. (1985) in ileal-cannulated cockerels (66%) and Manangi et al. (2007) in ileal-cannulated hens (70%), but was less than that reported by Van Leeuwen et al. (2000) in ilealcannulated roosters (greater than 90%). The differences in the survival rates of surgical cannulation between the present and previous studies might relate to the type of cannula, the position of the cannulation in the intestine, and the species of animal (Harmon and Richards, 1997). Our results suggest a surplus of 25% of experimental animal numbers is necessary to use intestinal-cannulated ducks.