XII - 12th International Symposium - Digestive Physiology of Pigs

Digestive
Physiology
of Pigs
when significant value for treatment effect (P < 0.05) was
observed, the differences between means were assessed
using Fisher’s LSD procedure. At HT conditions, feed intake
was lower (P = 0.016) than at NT conditions. Exposure of
pigs to high environmental temperature tended to lower (P
= 0.07) digestibility of nitrogen (85.2%) as compared with
NT conditions (87.6%). Urinary N excretion increased by
19.6% (P = 0.0175) and N retention decreased by 20.6%
(P = 0.001) at HT in comparison with NT. The N retention at
NT and HT conditions was 32.6 and 25.8 g/d, respectively.
Daily nitrogen retention decreased by 4.6 g per each 1°C
above upper critical temperature of animals (y = −4.5819x
+ 164.03; R 2 = 0.4083; P < 0.001). In conclusion, when
pigs are exposed for long-term periods to continuous high
environmental temperatures, N retention and digestibility
decrease, presumably due to decreased utilization of
metabolisable energy during respiration.
Key words: heat stress, pigs, nitrogen retention
1050 The supplementation of low-P diets with microbial
6 phytase from Aspergillus oryzae improves P
and Ca digestibility in growing pigs. D. Torrallardona* 1 ,
R. Salvadó 1 , and J. Broz 2 , 1 IRTA-Mas de Bover, E-43120
Constantí, Spain, 2 DSM Nutritional Products Ltd., CH-4002
Basel, Switzerland.
A trial was conducted to evaluate a novel microbial 6
phytase obtained from Aspergillus oryzae (Ronozyme ®
HiPhos, DSM) at different doses in pigs. Forty 8 individually
housed pigs (Landrace x Pietrain; 52 kg BW; 1/2 males, 1/2
females) were distributed among 6 experimental treatments
consisting of a basal control diet low in P (3.5 g P/kg; 1.1 g
digestible P/kg), which was supplemented with 500, 1,000,
2,000, or 4,000 FYT/kg of phytase, and a positive control
diet supplemented with dicalcium phosphate (4.5 g P/kg; 1.8
g digestible P/kg). After 21d, fresh feces were sampled from
all the animals and the apparent fecal digestibility of nutrients
was measured using TiO 2 as indigestible marker. Blood
samples were also obtained from each pig and analyzed
for P and Ca concentrations. The basal control low-P diet
increased Ca and reduced P blood concentrations (P <
0.05) relative to the positive control diet (10.8 vs. 10.2 and
6.7 vs. 7.7 mg/dL, respectively). Phytase supplementation
reduced Ca (from 10.8 to 9.9 mg/dL; linear response; P <
0.001) and increased P concentrations (from 6.7 to 8.0 mg/
dL; linear and quadratic responses; P < 0.001) in blood, and
reduced P concentration in feces (from 13.8 to 7.7 g/kg DM;
linear and quadratic responses; P < 0.001). Phytase also
improved the fecal digestibility of P (from 29.6 to 62.4%;
linear and quadratic responses; P < 0.001 and P < 0.05),
Ca (from 55.3 to 75.9%; quadratic response; P < 0.01) and
ash (from 46.4 to 57.7%; quadratic response; P < 0.01). It is
concluded that the microbial 6-phytase tested improves the
apparent fecal digestibility of P in growing pigs and reduces
P excretion in feces in a dose-dependent manner.
Key words: phytase, digestibility, pigs
1051 The supplementation of low-P diets with microbial
6 phytase from Aspergillus oryzae improves P
digestibility in sows. D. Torrallardona* 1 , L. Llauradó 1 ,
XII INTERNATIONAL SYMPOSIUM ON
DIGESTIVE PHYSIOLOGY OF PIGS
59
Session II
and J. Broz 2 , 1 IRTA-Mas de Bover, E-43120 Constantí,
Spain, 2 DSM Nutritional Products Ltd., CH-4002 Basel,
Switzerland.
Two trials were conducted to evaluate a novel microbial
6 phytase obtained from Aspergillus oryzae (Ronozyme
HiPhos, DSM) in gestating and lactating sows. In the first
trial, 24 sows (Duroc × Landrace; 223 kg BW) were offered,
at 16 d of gestation, a low-P control diet (4.0 g total P/kg; 1.5
g digestible P/kg) supplemented with 0, 500 or 1,000 FYT/
kg of phytase. Two weeks later, fresh feces were sampled
from all the animals and the apparent fecal digestibility of P
was measured using TiO 2 as indigestible marker. Phytase
supplementation did not significantly (P > 0.1) affect the
fecal digestibility of P despite of numerical improvements
from 8.7% in the non-supplemented diet to 17.6 and
19.1% in the diets with 500 and 1,000 FYT/kg of phytase,
respectively, but reduced P concentration in feces (from
14.5 to 12.0 and 12.0 g/kg DM; P < 0.05). In the second
trial, 32 lactating sows (Duroc × Landrace; 282 kg BW) were
used. They were offered, at 7 d of lactation, a low-P control
diet (6.1 g total P/kg; 3 g digestible P/kg) or the same diet
supplemented with 500 FYT/kg of phytase. After 2 weeks,
fresh feces were sampled from all the animals and the
apparent fecal digestibility of P was measured using TiO2
as indigestible marker. Phytase supplementation improved
the apparent fecal digestibility of P from 27.5 to 38.7% (P <
0.001) and reduced P concentration in feces (from 27.5 to
21.4 g/kg DM; P < 0.001). It is concluded that the microbial
6-phytase tested improves the apparent fecal digestibility of
P in sows and reduces P excretion in feces.
Key words: phytase, digestibility, sows
1052 Differences in portal appearance of lysine, threonine
and methionine in Iberian and Landrace pigs fed
diets differing in protein content. L. Gonzalez-Valero, J.
M. Rodriguez-Lopez, M. Lachica, and I. Fernandez-Figares,*
Estacion Experimental del Zaidin, CSIC, Granada,
Spain.
The Iberian pig is an obese breed that is used for production
of unique and value added pork products. Compared with
modern breeds, Iberian pigs have lower rates of muscle
protein deposition and body weight gain. Factors that
limit growth performance of Iberian pigs are not known.
The objective of this work was to determine the portal
appearance of Lys, Thr and Met, the AAs most frequently
limiting in practical diets, in Iberian and Landrace gilts fed
diets with different protein content. Net portal absorption
of AAs during the 6 h postprandial period was measured
in 6 Iberian and 6 Landrace gilts (28 kg BW) fitted with
chronic catheters placed in the portal vein, carotid artery
and mesenteric vein, trained to consume 25 and 75%
of their daily ration (85% ad libitum) at 9.00 and 15.00,
respectively. Blood samples were taken every 30 min for
4 h and then hourly until 6 h after feeding 2 isoenergetic
barley-soybean meal diets (14–14.5 MJ ME/kg DM) with
different CP (14 vs. 16%) in a crossover design, with an
adaptation period of one week for both diets. Net portal
AA absorption was calculated by multiplying porto-arterial
plasma AA concentration difference by portal vein plasma