XII - 12th International Symposium - Digestive Physiology of Pigs

Digestive
Physiology
of Pigs
1083 Net energy of Canadian feedstuffs in growing
finishing pigs. S. Moehn,* R. T. Zijlstra, and R. O. Ball,
University of Alberta, Edmonton, AB, Canada.
The objective was to determine the energy content of
diets based on Canadian feedstuffs of major importance
for pig production. Two sets of 8 castrated male pigs were
surgically fitted with T-cannulas at the terminal ileum.
Diets containing barley, wheat, corn, field pea, soybean
meal, zero-tannin fava bean, canola meal or corn DDGS
were formulated so that dietary methionine (pea, bean) or
lysine (other feedstuffs) content limited protein deposition
to similar rates to minimize its impact on dietary net energy
(NE) determination. Diets contained 0.5% of Cr 2 O 3 as an
indigestible marker and between 5 and 64% of a constantratio
mix of cornstarch, sugar, canola oil and cellulose. Diets
were offered twice daily at 2.5 × energetic maintenance
requirement (458 kJ/kg 0.75 BW). Experimental periods
consisted sequentially of a 7-d adaptation, 4-d N-balance
and apparent total tract digestibility (ATTD) determination,
2 12 h ileal digesta collections, and 24 h of indirect
calorimetry. Data were analyzed in SAS with diet and BW
as main effects. Mean BW (61.2 kg SE 1.7) and feed intake
(1,798 g/d SE 40.6), daily gain (631 g/d SE 23.9) and gain:
feed (0.36 SE 0.013) did not differ (P > 0.1) among diets.
The ATTD of energy was lowest (P < 0.05) for the DDGS
diet (65.9% SE 2.90) and highest for the control diet (i.e.,
soybean meal diet without added AA, 86.7% SE 0.44). The
ranking of energy content was similar for feedstuffs within
the 3 energy systems. The digestible, metabolizable and net
energy content was greatest (P < 0.05) for the control diet
at 14.3 (SE 0.08), 13.5 (SE 0.08) and 12.4 (SE 0.38) MJ/kg,
respectively, and was lowest (P < 0.05) for the canola meal
diet at 11.3 (SE 0.50), 9.3 (SE 0.81) and 8.9 (SE 0.35) MJ/
kg, respectively. Subtracting the N-free mix in the diets, the
estimated NE contents were 12.4 MJ/kg (wheat), 11.7 MJ/
kg (corn), 11.6 MJ/kg (barley), 11.5 MJ/kg (field pea), 10.3
MJ/kg (soybean meal), 10.1 MJ/kg (fava bean), 8.5 MJ/kg
(DDGS) and 6.5 MJ/kg (canola meal). These measured NE
contents ranked feedstuffs similar to NRC (1998).
Key words: growing pig, feedstuff, net energy
1084 Slowly-digestible starch influences mRNA abundance
of glucose and short chain fatty acid (SCFA)
transporters in the porcine distal intestinal tract. A. D.
Woodward* 1 , P. R. Regmi 1 , M. G. Gänzle 1 , T. A. T. G. van
Kempen 2 , and R. T. Zijlstra 1 , 1 University of Alberta, Edmonton,
AB, Canada, 2 North Carolina State Univ., Raleigh, NC,
USA.
The relationship between starch chemistry and nutrient
transporters in the intestinal epithelium is not well known.
We hypothesized that inclusion of slowly-digestible instead
of rapidly-digestible starch in pig diets will decrease
glucose and increase SCFA transporter expression in the
distal gut. Thus, weaned barrows (n = 32) were fed 4 diets
containing 70% rapidly- to slowly-digestible starch [ranging
from 0 to 63% amylose and 1.06 (rapidly) to 0.22%/
min (slowly) rate of in vitro digestion] at 3 × maintenance
energy requirement in a complete randomized design.
Ileal and colon mucosa was collected on d 21 to quantify
XII INTERNATIONAL SYMPOSIUM ON
DIGESTIVE PHYSIOLOGY OF PIGS
71
Session II
mRNA abundance of Na + -dependent glucose transporter-1
(SGLT1), monocarboxylic acid transporter-1 (MCT1),
and Na + -coupled monocarboxylate transporter (SMCT).
Messenger RNA was extracted and cDNA manufactured
before relative quantitative reverse transcription-PCR.
Data were analyzed using the 2-ΔΔC method, with β-actin
T
and GAPDH as reference genes, and regression analysis
was performed. As in vitro rate of digestion decreased,
SGLT1 increased linearly (P < 0.05) in the ileum and
quadratically (P = 0.08) in the colon. Contrary to SGLT1,
MCT1 tended to decrease linearly (P = 0.08) in the ileum
and increased quadratically (P < 0.001) in the colon with
decreasing rate of digestion. Starch digestion rate did
not affect SMCT in the ileum; however, SMCT decreased
quadratically (P < 0.01) with decreasing rate of digestion. In
conclusion, in contrast to our hypothesis, slowly-digestible
starch increased ileal glucose and decreased ileal SCFA
transporter mRNA abundance, possibly due to an increased
presence of glucose in the lumen of the ileum. Effects of
starch on colonic SCFA transporter mRNA abundance were
inconsistent, with slowly-digestible starch increasing MCT1
but decreasing SMCT.
Key words: glucose, short-chain fatty acid, transporter
1085 Net energy of Canadian feedstuffs in pregnant
sows. S. Moehn,* R. T. Zijlstra, and R. O. Ball, University of
Alberta, Edmonton, AB, Canada.
The objective of this experiment was to determine dietary
energy contents in diets based on Canadian-grown
feedstuffs for sows, in comparison to growing pigs. Ten
pregnant parity 2 or 3 sows were used to test the same
feedstuffs as used in the growing-finishing pig experiment.
Diets were formulated in the same manner as for growing
pigs, and offered to the sows randomly to obtain 6
observations per diet. Diets contained 0.5% of Cr 2 O 3 as an
indigestible marker and between 3 and 67% of a constantratio
mix of cornstarch, sugar, canola oil and cellulose.
Diets were offered twice daily according to the sow′s BW
and back fat at breeding. Experimental periods consisted
of 7 d adaptation, 4 d apparent total tract digestibility
(ATTD) determination and 24 h of indirect calorimetry. Data
were analyzed in SAS with diet and BW as main effects.
Mean BW (214 kg, range 172 - 277 kg), feed intake (2.62
kg/d SE 15.1), heat production (31.7 MJ/d SE 0.35) and
respiratory quotient (1.07 SE 0.011) did not differ (P > 0.4)
among diets. Regressing heat production on metabolizable
energy (ME) intake estimated fasting heat production as
22.5 MJ/d (402 kJ/kg 0.75 BW) and marginal efficiency of
energy utilization for energy retention as 0.74. The ATTD
of energy was lowest for the DDGS diet at 84.6% (SE 0.71)
and greatest for the soybean meal diet at 95.6% (SE 0.97).
The ranking of dietary energy content was similar for the
digestible energy and ME: highest (P < 0.05) found for
soybean meal, field pea and fava bean diets, and lowest for
the DDGS diet. Diet NE increased from 2nd to 3rd parity (P
= 0.048) and with increasing BW (P = 0.021). Subtracting
the N-free mix in the diets, the estimated NE contents were
11.9 MJ/kg (wheat), 11.6 MJ/kg (corn), 11.1 MJ/kg (corn
DDGS, barley), 10.6 MJ/kg (field pea), 9.4 MJ/kg (soybean
meal), 8.3 MJ/kg (fava bean) and 7.7 MJ/kg (canola meal).