This
study investigated the effect of chilling and freezing canine feces on in vitro gas production kinetics and
fermentation end-product profiles from carbohydrate-rich and protein-rich
substrates. Feces were collected from three adult Retriever-type dogs fed a wet
diet for at least two weeks. Each fecal sample was divided into three portions:
one used as an inoculum (fresh) and the other two used after either chilling to
5°C for 30 minutes and storage in crushed ice for 23.5 hours (chilling) or
freezing to -20°C for 30 minutes and storage in a pre-frozen (-20°C) container
for 23.5 hours (freezing).
After
incubation, fermentation liquids were analyzed for short-chain fatty acids, NH3
and aromatic compounds. Chilling feces did not affect gas production kinetics
and end-product profiles of substrates compared to inocula from fresh feces.
Freezing feces decreased the maximum rate of gas production in FOS and across
substrates increased gas produced and time of maximum gas production. Furthermore,
compared to fresh fecal inocula, inocula from frozen feces resulted in increased
overall indole concentrations. Phenol concentrations were greater for frozen
feces than for fresh feces.
Freezing
canine feces for 24 hours slightly altered fermentative characteristics of
fecal inoculum, whereas chilling feces in crushed ice for 24 hours maintained
fermentative characteristics. Chilling in crushed ice is a practical method to
preserve feces during transport between laboratories within 24 hours for in vitro fermentation studies evaluating
dietary ingredients.
Source: G. Bosch et al., 2012. Effects of preservation
conditions of canine feces on in vitro
gas production kinetics and fermentation end-products. J Anim Sci online October 2012. doi: 10.2527/jas.2012-5262J