XII - 12th International Symposium - Digestive Physiology of Pigs

Digestive
Physiology
of Pigs
of the fermented EGF-LL (Supern). The amount of EGF
was determined in the fermentation product and pigs were
given 70–100 ug EGF/kg/day during the first 3 weeks
post-weaning; growth performance was monitored for 4
weeks. Daily body weight gain (197 vs. 200 g/d; SEM 12)
and Gain:Feed (0.450 vs 0.454; SEM 0.020) of pigs on
the Ferm group was similar to that of the Control; these
measures of performance were improved (254 g/d and
0.540; P < 0.01) for pigs on Supern. Sucrase levels on d 9
of treatment were increased in Supern pigs (166.3 vs. 81.4
nmol glucose released/mg protein; P < 0.05) compared with
Control; sucrase levels of Ferm pigs were variable (202.2
nmol glucose released/mg protein). The lack of response to
Ferm was likely due to an overload of bacteria (daily dose
included 9.13x109 EGF-LL). These results suggest that the
EGF-LL fermentation product, after removal of EGF-LL, is
effective in increasing growth performance of early-weaned
piglets, can be used to reduce post-weaning growth lag,
and may reduce reliance on feeding antibiotics and high
quality animal proteins.
Key words: epidermal growth factor, probiotics, growth
performance
2049 early weaning decreases sodium-dependent
acidic ileal excitatory amino acid carrier-1 (EAAC1)
gene expression in pigs. Q. J. Wang 1 , C. Yang 2 , X. Teng 1 ,
L. Xu 1 , D. Lackeyram* 3 , K. Lien 4 , and M. Fan 3 , 1 Northeast
Agricultural University, Harbin, Heilongjiang Province,
China, 2 Lucta-Guangzhou Flavors Co., Ltd., Guangzhou,
Guangdong Province, China, 3 University of Guelph,
Guelph, Ontario Canada, 4 University of Alberta, Edmonton,
Alberta, Canada.
Enteral glutamate is preferentially used as metabolic
fuel and for glutathione biosynthesis in the gut mucosa.
Enterocyte apical excitatory amino acid carrier 1 (EAAC1)
plays an essential role in uptake of luminal acidic AA
glutamate. The glutamate transport-associated protein
3–18 (GTRAP3–18) is known to regulate post-translational
trafficking and apical membrane anchoring of EAAC1. This
study was conducted to examine the effect of early weaning
on adaptive changes in glutamate concentration, status of
oxidative stress, EAAC1 and GTRAP3–18 gene expression
in ileum in weanling pigs (n = 6) compared with the suckling
counterpart (n = 6) in Yorkshire pigs at ages of 10–22 d
(initial BW 3.23 ± 0.13 kg). Ileal tissue samples were
partitioned into apical membrane and cytosolic fractions by
differential centrifugation. Target gene protein abundances
were analyzed by Western blotting while their gene mRNA
relative abundances were measured by quantitative RT-
PCR with the Quantitect SYBR Green kit by using β-actin
as a housekeeping control. Weaning decreased (P < 0.05)
ileal free glutamate concentration (7.92 vs. 9.24, SEM =
0.29 mM) by 14% but did not significantly influence total
antioxidant capacity and glutathione levels in the ileum
compared with the suckling piglets. Weaning reduced (P <
0.05) abundances of the 57-kDa pre-mature EAAC1 protein
associated with ileal homogenate and the intracellular pool
by 17 and 33%, respectively, and abundance of the 73-kDa
mature EAAC1 protein associated with the apical membrane
XII INTERNATIONAL SYMPOSIUM ON
DIGESTIVE PHYSIOLOGY OF PIGS
113
Session IV
by 22%. Weaning decreased (P < 0.05) abundance of the
50-kDa GTRAP3–18 dimer protein associated with the ileal
homogenate, the intracellular pool and the apical membrane
by 8, 27, and 16%, respectively. Weaning also reduced (P
< 0.05) the ileal EAAC1 mRNA relative abundance by 73%
without affecting the ileal GTRAP3–18 mRNA abundance.
In conclusion, early weaning decreased the ileal free
glutamate concentration and the apical acidic sodium-
AA co-transporter EAAC1 abundance in association with
GTRAP3–18 but did not affect status of oxidative stress in
the ileum of early-weaned pigs.
Key words: early-weaned pigs, gene expression, sodiumacidic
amino acid co-transporter EAAC1
2050 early weaning up-regulates jejunal neutral
amino acid exchanger (ASCT2) gene expression in
pigs. X. Teng 1 , Q. J. Wang 1 , C. Yang 2 , and M. Fan* 3 , 1 Northeast
Agricultural University, Harbin, Heilongjiang Province,
China, 2 Lucta-Guangzhou Flavors Co., Ltd., Guangzhou,
Guangdong Province, China, 3 University of Guelph,
Guelph, Ontario Canada.
Although the intestinal apical Na and Cl − dependent, broadspectrum
neutral AA exchanger ASCT2 (SLC1A5) activity
does not lead to increased enterocyte net uptake of neutral
AA, expression of the apical ASCT2 is known to sensing
the luminal neutral AA availability as stimuli to enhance gut
mucosal growth via the mammalian-target-of-rapamycin
(mTOR) signaling. This study was conducted to examine the
effect of early weaning on adaptive changes in ASCT2 gene
expression in jejunum of weanling pigs (n = 6) compared
with the suckling counterpart (n = 6) in Yorkshire pigs at ages
of 10–22 d (initial BW 4.48 ± 0.26 kg). The proximal jejunal
tissue samples were partitioned into apical membrane
and cytosolic fractions by differential centrifugation. Target
gene protein abundances were analyzed by Western
blotting while their gene mRNA relative abundances were
measured by quantitative RT-PCR with the Quantitect
SYBR Green kit by using β-actin as a housekeeping control.
A 57-kDa ASCT2 protein was identified in the jejunum
tissue homogenate, the intracellular fraction and on the
apical membrane. Weaning increased (P < 0.05) ASCT2
protein abundance in the jejunal homogenate and the
intracellular soluble fraction by 25 and 26%, respectively,
without significantly affecting ASCT2 protein abundance (P
= 0.93) on the apical membrane compared with the suckling
piglets. Furthermore, weaning dramatically enhanced (P =
0.0095) the relative abundance of the jejunal ASCT2 gene
SLC1A5 mRNA by 109% in comparison with the suckling
piglets. In conclusion, early weaning enhances the jejunal
neutral AA exchanger ASCT2 gene SLC1A5 expression
and preserves the apical ASCT2 protein abundance, which
should biologically support potential practices of dietary
supplementation of crystalline neutral AA for improving
trophic gut growth and performance via the mTOR-signaling
pathway in the early-weaned pigs fed corn and SBM-based
low-cost weanling diets.
Key words: Early-weaned pigs, Gene expression, Neutral
AA exchanger ASCT2