XII - 12th International Symposium - Digestive Physiology of Pigs

Digestive
Physiology
of Pigs
flow rate estimated using p-aminohippuric acid infused
into the mesenteric vein. Repeated measures analyses
were carried out using the mixed procedure of SAS. The
interaction of diet and breed with time was not significant
(P > 0.10). Portal plasma Lys and Met concentrations in
pigs were maximal by 0.5 h postprandial although Thr
peak occurred 1.5 h postprandial. Net portal absorption
of Lys was greatest (P < 0.05) when pigs consumed the
16% CP (34 vs. 24 μmol/min) diet and no differences (P
> 0.10) were found between breeds. Net portal absorption
of Thr was greatest in Landrace (154 vs. 46 μmol/min; P <
0.001) and in pigs fed 16% CP diet (135 vs. 66 μmol/min;
P < 0.01). Net portal absorption of Met (3.7 μmol/min) was
neither affected by breed or diet (P > 0.10). Differences in
portal appearance of limiting AAs may partially explain the
disparate growth capacity of Iberian pigs compared with
modern genotypes.
Key words: portal absorption, amino acid, pig
1053 Lower gut nitrogen supply has no effect on
apparent ileal digestibility of nitrogen or amino acids in
growing pigs. D. Columbus* 1 , M. F. Fuller 2 , and C. F. M. de
Lange 1 , 1 Department of Animal and Poultry Science, University
of Guelph, Guelph, Ontario, Canada, 2 Department
of Surgery, State University of New York, Stony Brook, New
York, USA.
An implicit assumption in measures of ileal digestibility (ID)
to estimate bioavailability of amino acids (AA) and nitrogen
is that ID is not influenced by lower gut nitrogen metabolism.
The absorption of nitrogenous compounds from the lower
gut, derived from fermentative AA catabolism, may have an
impact on nitrogen metabolism and microbial AA synthesis
in the upper gut as a result of urea recycling. The objective
of this trial was to determine the apparent ID of nitrogen
and AA in growing pigs fed a cornstarch and soybean
meal-based diet and receiving an infusion of nitrogen into
the cecum at 40% of nitrogen intake. Eight pigs (initial
BW of 23.3 ± 0.55 kg) were fitted with simple T-cannulas
in the ileum and cecum, and randomly assigned to 1 of
3 continuous cecal infusion treatments (saline, sodium
caseinate, or urea) according to a crossover design with 3
periods. Each experimental period lasted 9 d and consisted
of a 5 d adaptation period followed by 2 consecutive 2 d
collection periods. Digesta samples were collected and
pooled per pig for each 2 d period, freeze-dried, ground,
and analyzed for dry matter, organic matter, total nitrogen,
and AA. Titanium dioxide was included in the diet as an
indigestible marker. There was no effect of lower gut nitrogen
supply on apparent ID of dry matter, organic matter, total
nitrogen (85.4, 83.4, and 82.7 ± 1.74%; P = 0.31), or any
AA (90.1, 89.0, and 89.9 ± 1.08% for lysine; P = 0.70) for
saline, casein, and urea treatments, respectively. Apparent
ileal digestibility may be an insufficiently sensitive measure
to determine effects of lower gut nitrogen metabolism on
nitrogen absorption from the lower gut and subsequent
recycling into the upper gut.
Key words: lower gut, fermentation, ileal digestibility
XII INTERNATIONAL SYMPOSIUM ON
DIGESTIVE PHYSIOLOGY OF PIGS
60
Session II
1054 The effect of supplementing a xylanase to nursery
diets on growth performance of 9 to 36 kg Bw pigs.
E. Fruge 2 , E. Hansen 2 , R. Cabrera* 1 , and J. Foss 1 , 1 Huvepharma
USA, Inc., Peachtree City, GA, 2 Hubbard Feeds,
Inc., Mankato, MN.
Enzymes are promising tools to counteract the price
volatility in raw materials due to their ability to affect nutrient
digestibility. The challenge is to match the types and amounts
of non-starch polysaccharides (NSP) in ingredients with the
appropriate enzymes. The objective of this trial is to determine
the impact of a xylanase on growth and economic performance
in nursery pigs. A total of 991 pigs were randomly allocated to
3 dietary energy treatments: positive control (PC) with 3,344
kcal/kg of ME, negative control (NC) with 3,267 kcal/kg of ME
and negative control + Xylanase (NC+X) with 3,267 kcal/kg
of ME. Xylanase was added to phase 2 and 3 diets at 1,500
EPU/kg of feed respectively. Phase 2 diet had corn, SBM,
ground steam rolled oats and 10% DDGS. Phase 3 diet was
a straight corn-SBM with 20% DDGS. Pens of pigs were
weighed every 7 d until the end of the experiment on d 42.
Each treatment had 12 pens and pigs were stocked 27 pigs/
pen. PROC GLM of SAS was used and P < 0.05 was chosen
to determine the statistical differences among the treatments.
From d 0 to d 14 (9 to 15 kg of BW), dietary treatments did
not differ for ADG, ADFI, FG, and total gain. From d 14 to d 42
(15 to 36 kg of BW), PC and NC+X treatments had greater (P
= 0.03) ADG (0.74 and 0.73 vs. 0.71 kg/d respectively) and
total gain (20.6 and 20.4 vs. 19.8 kg respectively) than NC.
PC also had increased (P = 0.05) feed conversion (1.47 vs
1.54) when compared with NC. From d 0 to d 42 (9 to 36 kg
of BW), NC+X had intermediate response in both ADG and
total gain when compared with PC and NC treatments. PC
had greater (P = 0.05) ADG (0.64 vs. 0.62 kg/d respectively)
and total gain (26.9 vs. 26.2 kg respectively) than NC and
increased (P = 0.05) feed conversion (1.41 vs. 1.47 and
1.45 respectively) when compared with either NC or NC+X.
In conclusion, the improvement in FCR of pigs fed NC + X
confirms an improvement of dietary energy utilization equal
to approximately 33 Kcal/kg of ME.
Key words: xylanase, metabolizable energy, FCR
1055 The effects of supplementation of a novel bacterial
6-phytase on mineral digestibility and plasma minerals
in lactating sows. Z. Nasir* 1 , J. Broz 2 , and R. T. Zijlstra
1 , 1 University of Alberta, Edmonton, AB, Canada, 2 DSM
Nutritional Products, Basel, Switzerland.
Phosphorus present in plant feedstuffs is poorly digested
by pigs because endogenous phytase enzyme to hydrolyze
P from its complex phytate (inositol hexaphosphate) is
lacking, resulting in P excretion in feces. Phytate can also
bind other minerals. In most studies with piglets and growerfinisher
pigs, supplemental phytase increased digestibility
of minerals including P and Ca; however, data on efficacy
of phytase in lactating sows are scarce. As such, effects of
adding a novel bacterial 6-phytase expressed in a strain
of Aspergillus oryzae (Ronozyme HiPhos, DSM Nutritional
Products) on apparent total tract digestibility (ATTD) of P,
Ca and other minerals was assessed in 45 lactating sows
with free access to feed for the majority of the lactation.