Methods of determining digestibilty


Digestion trial vs. Metabolism trial

Digestion trial
Metabolism trial
Gives information on proportion of nutrients in a feed or diet that are absorbed from the gastro intestinal tract
Similar to digestion trials but gives more information on utilization of nutrient after absorption from the gastro intestinal tract
Information obtained
Information on digestibility co-efficient of nutrients
In addition to digestibility co-efficient, one gets information on nutrient balances such as nitrogen, calcium, pPhosphorus, energy etc. Hence, metabolism trials provide complete information on nutrient digestion and utilization from feedstuffs than digestion trials
What is collected
Only feces
In addition to feces, urine, milk, gases like co, sloughed hair, feathers etc are also collected
Apparent digestibility co-efficient of nutrients
In addition to apparent digestibility co-efficient of nutrients, the information on positive or negative nutrient balance is obtained

Methods of Determining Digestibility

I. In vivo method

  • In this animals like sheep, goat, rabbit, pig, dairy cattle etc in which digestibility of a feed is to be determined are used.
  • The two in vivo methods are :
    • Direct Method or Conventional method
    • Indirect: In the indirect method there are two methods:
      • Difference Method
      • Indicators/Markers Method

II. Semi in vivo methods

  • Nylon bag technique 
  • VIVAR technique

III. In vitro methods

  • Using rumen liquor
  • Using enzymes instead of rumen liquor
  • RUSITEC method
Last modified: Friday, 30 March 2012, 9:53 AM