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Protein digestion in pigs measured in vitro
1WB Tierernährung der Univ. Rostock, Liebig, DDR.
Archiv Fur Tierernahrung
|August 1, 1990
Summary
In vitro protein digestibility assays using pepsin-HCl or pepsin and trypsin do not accurately reflect ileal digestibility. Precipitating large polypeptides with copper hydroxide improves accuracy for nitrogen and lysine measurements.
Area of Science:
- Animal Nutrition
- Biochemistry
- Food Science
Background:
- In vitro protein digestibility assays are commonly used to assess feedstuffs.
- Existing in vitro methods using pepsin-HCl, pepsin, or trypsin show poor correlation with in vivo ileal digestibility.
- Accurate protein digestibility assessment is crucial for optimizing animal diets and reducing nitrogen excretion.
Purpose of the Study:
- To evaluate a modified in vitro method for determining protein digestibility.
- To compare results from the modified method with ileal protein digestibility figures.
Main Methods:
- Feedstuffs were treated with pepsin-HCl, pepsin, and trypsin separately.
- A modified method involved precipitating the largest polypeptides using copper hydroxide after peptic and tryptic treatment.
- Nitrogen (N) and lysine content were analyzed.
Main Results:
- In vitro protein digestibility results using standard pepsin-HCl, pepsin, or trypsin treatments differed significantly from ileal digestibility.
- Comparable results for N and lysine were obtained when using the modified method involving copper hydroxide precipitation.
Conclusions:
- Standard in vitro protein digestibility assays lack predictive accuracy for ileal digestibility.
- The modified in vitro method, utilizing copper hydroxide precipitation of large polypeptides, offers a more reliable approach for assessing protein and amino acid digestibility.