XII - 12th International Symposium - Digestive Physiology of Pigs

Digestive
Physiology
of Pigs
pigs of 35-d of age housed in pens with 2 4-space feeders
with diets offered in a paired choice as mash (Exp. 3) or
pellets (Exp. 4) for 3 consecutive 7-d periods (3 d non test,
4 d preference). Diets were formulated to equal NE and
SID AA using canola oil and synthetic AA. Feeding up to
20% napus CM to pigs did not affect growth performance.
Increasing inclusion of juncea CM linearly reduced (P <
0.001) ADFI, ADG and feed efficiency. In Exp. 3 and 4,
pigs preferred SBM (P < 0.001) over napus and juncea CM
diets, and pigs preferred napus CM (P < 0.001) over juncea
CM diet. Glucosinolates likely reduced feed preference
in juncea CM more than napus CM. The reduced growth
performance of pigs fed juncea CM diets was associated
to its higher glucosinolate content, most likely the bitter
gluconapin-type dominant in juncea CM than the proigotrintype
dominant in napus CM. In conclusion, although pigs
clearly preferred the SBM diet over napus or juncea CM
diets, when given no choice, napus CM but not juncea
CM can replace up to 20% SBM in diets for weaned pigs
without affecting growth performance. Finally, the contrast
of results between preference and performance studies
feeding CM to pigs indicates that results of preference
studies should be interpreted cautiously until validated by
pig growth performance data.
Key words: canola meal, preference, soybean meal
3039 Redox potential of cecum content of growing
pigs and its relation with ph and VFA concentration.
R. Lizardo* 1 , N. Tous 1 , M. A. Calvo 2 , C. Sampsonis 3 , R.
D’Inca 3 , and J. Brufau 1 , 1 IRTA - Institut de Recerca i Tecnologia
Agroalimentaries, Constantí, Tarragona, Spain, 2 UAB
- Universidad Autónoma de Barcelona, Bellaterra, Barcelona,
Spain, 3 LFA - Lesaffre Feed Additives, Marcq-en-
Baroeul, Lille, France.
Digestive microflora is partly responsible for physiological
gut conditions. Bacteria density in pig cecum exceeds 10 9
logCFU/g of digesta suggesting a high fermentation activity.
The cecal milieu is anaerobic which suppose a redox
potential (Eh) markedly negative, reflecting the absence
of oxygen and a strong reducing power. Measurements of
Eh and pH of digesta can give a basis for understanding
microbial activity and dynamics of fermentation. However,
few studies have assessed the Eh of the gastro-intestinal
tract of pigs. Twenty-four pigs of around 30 kg liveweight
were slaughtered to measure Eh and pH of cecum content
in situ and, samples of ileum, cecum and colon contents for
VFA determinations were taken. Pigs were previously fed
with a non-medicated starter feed for 5 weeks. The cecum
was reached through an incision on the abdomen then a
second small incision (2–2.5 cm) was made to insert Eh and
pH electrodes. Measurements were recorded first at 2 min
and then each 5 min for 35 min to estimate kinetics and the
delay to reach stabilization of Eh value. Cecum Eh dropped
rapidly from −115 to −180 mV for 15th min after insertion
of electrodes (P < 0.001) and then slowly decreased until
−185 mV at 35 min. Cecal pH starts at 5.74 decreasing
slowly afterward until 5.53 after 35 min (P < 0.01). The
Eh value after stabilization was negatively correlated
with final pH (r = −0.64; P < 0.001). Acetic, propionic
and butyric acids account for 58.7, 24.0 and 12.8% of
XII INTERNATIONAL SYMPOSIUM ON
DIGESTIVE PHYSIOLOGY OF PIGS
133
Session VI
total VFA production of cecum content, respectively. VFA
production of ileal content was lower when compared with
cecum or colon (50.8, 142.1 and 130.8μmol/g; P < 0.001)
and a higher proportion of formic and lactic acids was
detected (32.3 and 27.0%, respectively). Proportions of
acetic and propionic acids were correlated negatively (r =
−0.53; P < 0.01) and positively (r = 0.66; P < 0.001) with
Eh, respectively. In conclusion, cecal Eh was not easily
measured, but predicted fermentative activity. So, it can be
considered in future research relating feed additives and
digestive physiology.
Key words: piglet, redox potential, cecum
3040 Blood sampling and hemolysis affect concentrations
of plasma nutrients. P. K. Theil* 1 , L. J. Pedersen 1 ,
M. B. Jensen 1 , C. C. Yde 2 , and K. E. Bach Knudsen 1 , 1 Dept.
of Animal Science, Aarhus University, Foulum, DK-8830
Tjele, Denmark, 2 Dept. of Food Science, Aarhus University,
Kirstinebjergvej 10,, DK-5792 Aarslev, Denmark.
Blood sampling of peripheral blood may be collected by
vein puncture or from a catheter. The latter is preferred
because stress of the animal and hemolysis of collected
plasma is avoided, but most studies use vein puncture.
This study aimed to reveal metabolites sensitive to stress
and/or hemolysis and quantify the effect on metabolite
concentrations. Blood was collected from early and mid
pregnant sows fed one of 2 different diets. A total of 24
sows were blood sampled using vein puncture during
nose snaring and another 30 sows were blood sampled
via jugular vein catheters. Sows were fed twice daily (08
and 15 h) and blood sampled repeatedly 1, 4, 11 and 23
h after morning feeding. Plasma levels of isobutyrate (P
< 0.001), NEFA (P < 0.01), and acetate (P < 0.05) were
lowered, and plasma levels of caproate (P < 0.001),
glucose (P < 0.01), lactate, and isovalerate (P < 0.05) were
elevated in samples obtained via vein puncture. Plasma
insulin, propionate and butyrate were not sensitive to the
blood sampling procedure. These findings suggest that
concentrations of many plasma metabolites are sensitive to
the blood sampling procedure, likely due to stress imposed
on the animal. Hemolysis is a common problem when blood
is collected by vein puncture and the effect of hemolysis
on plasma metabolite concentrations was studied in 48
sows fed 4 different diets (other conditions identical to that
described above). Plasma was categorized according to
no, minor or major hemolysis (clear (n = 218), yellow (n
= 97) or red (n = 37)) upon centrifugation. Plasma NEFA
(P < 0.001) and plasma insulin (P < 0.10) was lower in
hemolyzed samples while plasma propionate, caproate,
isovalerate (P < 0.001), isobutyrate (P < 0.05) and butyrate
(P < 0.10) was higher in hemolyzed samples compared with
clear plasma samples. Plasma glucose and lactate were
the only metabolites studied which were not affected by
hemolysis. No dietary interactions were found (P > 0.05). In
conclusion, blood sampling procedure and hemolysis affect
the measured metabolite concentrations and should be
considered or accounted for when comparing results within
and between experiments.
Key words: analysis interference, blood metabolites, pigs