Canine Diets Based on in Vitro Hindgut Fermentation

In animal nutrition, evaluation of diets based on digestibility and fermentation are

conducted conventionally by in-vivo trials. These experiments often meet with technical

difficulties and ethical questions. Therefore, in vitro models which can mimic gastrointestinal

digestion and fermentation processes are attempted as an alternative to the in vivo studies

(Peeters et al., 1998). In vitro techniques not only offer advantages of being relatively simple,

time saving, economical, producing repeatable estimates but they are less laborious compared

to animal experiments besides being ethically superior. One such in vitro fermentation

method is in vitro gas production technique, which exploits the relationship between

degradation and fermentative gas production to evaluate the nutritional parameters of

foodstuffs.

Several different methodologies have been proposed for the gas production technique,

each varying in its complexity, limitations and benefits. Although the gas production

technique has been used exclusively with ruminants, it may also be of value for nutritive

evaluation of foods for man and other monogastric animals (Coles et al., 2005). The benefits

of the technique include being able to run large batches simultaneously at low cost, the ability

to measure fermentation kinetics of soluble as well as insoluble fractions of food and

facilitation of relative comparisons among different foodstuffs. However, these in vitro

techniques of evaluation of diets need to be validated and justified by in vivo studies .

In monogastric animals like dogs, one of the factors which influence the health status

is the microbial fermentation in the hindgut (Williams et al., 2005). The large intestine of

dogs comprises a complex microbial ecosystem. In a healthy status, the diet and hindgut