Chemistry Reference
In-Depth Information
IgM immune response. No effects were noted with IgG and IgA, similar to previous
findings that these immunoglobulins were not affected by prebiotic supplementation
of dogs.
Recently, Respondek et al.
9
evaluated the effects of scFOS on insulin sensitivity
and adipose gene expression in obese and lean adult beagles. Dogs were fed a control
diet or the control + 1 percent scFOS (DM basis). In obese dogs, the rate of glucose
infusion was increased in dogs supplemented with scFOS during the euglycemic
hyperinsulinemic clamp, suggesting a greater insulin sensitivity compared to the
obese dogs fed the control diet. Supplementation with scFOS also led to increases in
adipose tissue gene expression, including uncoupling protein 2 and carnitine palmi-
toyl transferase 1. Both genes play an active role in fatty acid metabolism, and the
authors suggested that these increases may have contributed to the increased insulin
sensitivity noted. Outcome variables measured in this study are unique in prebiotic
supplementation research and demonstrate the need for further testing. Obesity is a
growing problem in both dog and cat populations throughout the developed world.
Finding dietary mechanisms that may ameliorate diseases associated with obesity
would be beneficial to those populations.
Modern technology now allows for a more thorough analysis of microbial
changes in the gut due to prebiotic supplementation. One of the first of these
studies conducted was by Vanhoutte et al.
10
and evaluated fecal samples from
healthy, adult dogs fed a control diet, control + 4.5 g/day OF, or control + 5.6 g/
day inulin. Utilizing denaturing gradient gel electrophoresis (DGGE), research-
ers evaluated population diversity of microbial species. The DGGE analysis
revealed a band that appeared or became more prominent after fructan supple-
mentation. This band then was excised and sequenced. The sequencing deter-
mined the band was
Streptococcus lutetiensis
. To date, the role of
S. lutetiensis
in the dog remains unclear.
Use of DGGE during prebiotic supplementation was evaluated further by
Middelbos et al.
11,12
These researchers evaluated six diets: (1) control—no supple-
mental fermentable carbohydrate; (2) control + 2.5 percent cellulose (poorly ferment-
able fiber source); (3) control + 2.5 percent beet pulp (moderately fermentable fiber
source); (4) control + 1.0 percent cellulose + 1.5 percent scFOS; (5) control + 1.0
percent cellulose + 1.2 percent scFOS + 0.3 percent YCW; and (6) control + 1.0 per-
cent cellulose + 0.9 percent scFOS + 0.6 percent YCW. Decreased total tract apparent
CP digestibility and increased fecal butyrate concentrations with prebiotic supple-
mentation were noted. By using DGGE and quantitative real-time PCR, changes in
fecal bacterial species were noted. An increase in fecal bifidobacteria and a trend for
increased lactobacilli were noted in dogs fed the prebiotic-supplemented diets.
Middelbos et al.
12
compared qPCR analysis to the more conventional method of
plating for microbiota enumeration. In this study, comparisons of differing doses
of YCW supplementation were evaluated in healthy, adult dogs. Using the plating
techniques, fecal
E. coli
decreased linearly and
Clostridium perfringens
responded
cubically to increasing YCW supplementation. Using q-RT-PCR,
E. coli
and lacto-
bacilli tended to respond cubically to increasing YCW supplementation. The authors
indicated that the differences in results obtained from the techniques to measure
