XII - 12th International Symposium - Digestive Physiology of Pigs

Digestive
Physiology
of Pigs
0 to 5 and d 5 to 19) with 10 and 20% DDGS, respectively.
At the end of the experiment, all pigs fed diets 1–4 were
euthanized and a section of the jejunum was removed for
use in modified Ussing chambers. Overall (d 0–19), ADG
was numerically higher for PC and NC+AP+P over all other
treatments (443, 409, 415, 438, 406 g/d, respectively).
There was a tendency (P < 0.10) for improved G:F for PC
and NC+AP+P over NC (0.730, 0.664, 0.675, 0.726, 0.689,
respectively). Active glucose absorption, estimated based
on changes in short circuit current was 9.78, 18.55, 23.89
and 25.05 μA/cm2 for the NC, PC, NC+AP+P, and NC+AP,
respectively (P = 0.39, pooled SEM = 17). Active phosphate
absorption, based on changes in short circuit current
following phosphate addition to the serosal chamber, was
highest (P < 0.05) for pigs fed the NC diet. The addition
of AP to the NC diet resulted in a 26% reduction in active
phosphate absorption (P < 0.05). Pigs fed the PC or the
NC+AP+P had further reductions in active phosphate
absorption of 53 and 64%, respectively, relative to the NC.
The addition of Alkaline Phosphatase plus phosphorus
recovered pig performance equal to the positive control.
These data indicate an increase in luminal phosphate
resulting in decreased active phosphate absorption with the
addition of alkaline phosphatase.
Key words: swine, alkaline phosphatase, nutrient
absorption
1135 The effects of β-mannanase and β-glucanase on
nursery pig growth performance, intestinal morphology
and active nutrient absorption. Z. Rambo* 1 , B. E.
Aldridge 1 , B. T. Richert 1 , J. Ferrel 2 , D. Anderson 2 , and J. S.
Radcliffe 1 , 1 Purdue University, West Lafayette, IN, USA,
2 ChemGen Corporation, Gaithersburg, MD, USA.
Forty-eight, crossbred pigs were weaned at ~19 d of age,
fed a starter diet for 7 d and then moved to individual pens,
where they were randomly allotted to treatments for a 21 d
experiment (Phase 1: d7–14, 10% DDGS; phase 2: d14–
28, 20% DDGS) to investigate the effects of β-mannanase
or β-mannanase + β-glucanase on growth performance,
intestinal morphology and active nutrient transport. Diets
were 1) Positive control (PC), 2) Negative control (NC,
reduced ME by 80 kcal/kg), 3) NC + β-mannanase (M), and 4)
NC + β-mannanase + β-glucanase (M+G). At the end of the
experiment, pigs were euthanized, intestines were weighed
and measured, and a section of the jejunum was removed
for histological examination and for use in modified Ussing
chambers as an indicator of active nutrient absorption.
Overall (d 7–28) ADG was 406, 406, 462, 455 g/d, for PC,
NC, M, M+G, respectively. Overall ADFI decreased (P =
0.05) for PC over M and G:F tended (P < 0.10) to be higher
for PC over NC while all others were intermediate (0.706,
0.635, 0.660, 0.674, respectively). The small intestine was
11% longer (P < 0.05) in M+G fed pigs compared with all
other diets. Stomach and intestinal weights, large intestine
lengths, villus height, crypt depth and the villus:crypt did not
differ. Basal short circuit current was greater (P < 0.01) for
M fed pigs compared with all other diets. Active glucose and
XII INTERNATIONAL SYMPOSIUM ON
DIGESTIVE PHYSIOLOGY OF PIGS
90
Session II
glutamine absorption, measured by a change in short-circuit
current, were greater (P < 0.05) in NC (83% increase) and
M (73% increase) fed pigs than PC or M+G fed pigs. Active
phosphate absorption was 87% greater (P < 0.05) for PC
fed pigs than M or M+G fed pigs, with NC fed pigs being
intermediate. Active Gly-Sar absorption, basal resistance,
and carbachol induced chloride ion secretion did not differ.
The addition of M improved ADG and ADFI in phase 2 with
numerical improvements in performance observed for the
overall period and for G:F with the enzyme combination
(M+G). These data suggest that the inclusion of M and G in
nursery pig diets containing 20% DDGS has the potential to
improve performance and modify nutrient uptake.
Key words: swine, β-mannanase, β-glucanase
1136 effects of dietary true digestible Ca to P ratio on
growth performance and efficiency of Ca and P utilization
in growing pigs. M. Fan,* C. de Lange, and T. Archbold,
University of Guelph, Guelph, Ontario, Canada.
Objectives of this study were to determine effects of
dietary true digestible Ca to true digestible P ratio on
growth performance and efficiency of Ca and P utilization
in growing pigs fed corn-SBM based diets. Experiment 1
was carried out to measure true fecal digestibility of Ca and
P as well as the fecal gastrointestinal endogenous outputs
of these nutrients associated with a corn-SBM based diet
in Yorkshire growing pigs by the substitution method. True
fecal digestibility (%, ± SEM, n = 6) of Ca (53.6 ± 12.7) and
P (43.8 ± 16.7) as well as the endogenous outputs (g/kg
DMI, ± SEM, n = 12) of Ca (0.91 ± 0.20) and P (1.31 ± 0.15)
associated with the diets were determined. Experiment 2
was conducted with 36 Yorkshire barrows of an average
initial BW of 24.2 kg and the pigs were fed 6 diets according
to a completely randomized block design. The 6 diets
were corn and SBM-based with diet 1 containing 0.2%
true digestible Ca and 0.3% true digestible P and were
formulated to contain 6 total Ca to total P ratios based on
analyzed dietary Ca and P contents (diet 1, 0.6:1; diet 2,
0.7:1; diet 3, 0.8:1; diet 4, 1.3:1; diet 5, 1.0:1; and diet 6:
1.3:1) by supplementing gradient levels of limestone with
dietary P level for meeting the recommended requirement.
Changes in the dietary Ca to P ratio had no effects (P >
0.05) on the average ADFI. Changes in the dietary Ca
to P ratio had a linear effect (P < 0.05) on the ADG with
optimal responses occurred in diets 2 to 4. Changes in
the dietary Ca to P ratio had linear, quadratic and cubic
effects (P < 0.05) on the feed conversion ratio with optimal
responses also occurred in diets 2 to 4. However, due to
a large variability, changes in the dietary Ca to P ratio had
no effects (P > 0.05) on dietary Ca and P digestibility and
their efficiency of retention. Efficiency of P retention was
numerically high in diets 2 and 3 but very low in diet 6. We
conclude that changes in dietary Ca to P ratio have effects
on growth performance in grower pigs.
Key words: calcium to phosphorus ratio, endogenous Ca
and P loss, grower pigs