Use of the mobile nylon bag technique for determination of apparent ileal digestibilities of crude protein and amino acids in feedstuffs for pigs
2011
Steiner, T., University of Hohenheim, Stuttgart (Germany). Inst. of Animal Nutrition | Bornholdt, U., Deutsche Tiernahrung Cremer GmbH and Co. KG, Mannheim (Germany) | Sauer, W.C., University of Alberta, Edmonton (Canada). Dept. of Agricultural, Food, and Nutritional Science | Ahrens, F., Ahrhoff GmbH, Boenen (Germany) | Joergensen, H., University of Aarhus, Tjele (Denmark). Dept. of Animal Health, Welfare and Nutrition | Mosenthin, R., University of Hohenheim, Stuttgart (Germany). Inst. of Animal Nutrition
Three digestibility experiments were conducted to evaluate the potential of determination of apparent ileal digestibilities (AID) of crude protein (CP) and amino acids (AA) by the mobile nylon bag technique (MNBT) using 21 feedstuffs and three mixed diets. In two conventional digestibility experiments (Exp. 1 and 2), AID were determined using 10 barrows (BW 35 kg) fitted with simple T-cannulas at the terminal ileum. For the MNBT studies, four pigs were fitted with a simple T-cannula at the proximal duodenum and a Post-Valve T-Caecum (PVTC) cannula at the terminal ileum. The MNBT studies included the feedstuffs (n = 10) from Exp. 1 and 2 as well as 14 further feedstuffs and mixed diets in which AID coefficients had been determined in previous trials. For each feedstuff 60 nylon bags were used. In vitro digestion of the bags was carried out in pepsin-HCl solution with 450 IU pepsin/L at pH 2.0 and 37 deg C for 4 h. In the 28-day in vivo experiment, 15 nylon bags per pig and day were inserted through the duodenal cannula and collected through the PVTC cannula after passage through the small intestine. Coefficients of AID were calculated based on the disappearance of CP and AA from the nylon bags during the in vitro and in vivo phase. In comparison with AID determined by the conventional method, AID of CP was on average 2.4% lower, whereas AID of lysine was on average 8.5% higher when determined by the MNBT. The correlation between AID coefficients determined by both methods was significant (P less than 0.05) for CP (r = 0.61) and some AA (r ranging between 0.62 and 0.72) in cereals only (n = 11). In conclusion, the potential of the MNBT to determine AID of CP and AA is rather limited. Differences in coefficients of AID of CP and AA were attributed to several factors such as diffusion of sample particles or endogenous protein through the nylon bags as well as to the presence of anti-nutritional factors (e.g. in legume seeds and oilseed meals).
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