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Current Research
Activities in Swine Nutrition
Weanling
Pig Research
-
Fatty
acids. Studies
are assessing omega-6:omega-3 fatty acid ratios
on performance, immunological, blood, and tissue
responses in young pigs.
- Brewers
yeast as a source of mannan-oligosaccharides
(MOS).
Brewers yeast (Brewtec®, International
Ingredients Corp.) was evaluated as a source
on MOS as a
possible alternative to antibiotics for
pigs. Performance was not improved by adding
brewers
yeast or carbadox to unmedicated starter
diets. In other experiments, the efficacy
of brewers
yeast in preventing colonization of pathogenic
E. coli K-88 in the gut of pigs is being
investigated.
- Ingredients
in starter diets. Amino-Lac®,
a product consisting of whey protein concentrate,
meat protein isolate, and yeast protein
(50% protein, 3.4% lysine) was comparable
to dried
animal plasma on a lysine basis and found
to be equal in nutritional value.
- Zinc
and antibiotics. We
cooperated with NCR-42 in a study to evaluate
the combination of high Zn (1,500 or 3,000 ppm,
from Zn oxide) and carbadox on performance of
weanling pigs. The combination of high Cu and
carbadox was additive. Another NCR-42 study assessed
Zn oxide (2,500 ppm Zn) and zinc methionine (250,
500, 750 ppm Zn). Zn oxide was more efficacious
than the organic Zn form. In another study, 2000,
and 3000 ppm added Zn from Zn oxide had markedly
increased Zn excretion compared with a low-Zn
control diet. High Zn had a slightly negative
effect on P, Cu, and Fe absorption, as well as
on liver Cu.
Growing-Finishing
Pig Research
- Low-phytate
corn. The
mutant lpa1 gene substantially reduces
the phytate content of corn without affecting
the total P. Experiments conducted with chicks
and pigs indicated that the P in low-phytate
corn (Optimum Quality Grains/DuPont Specialty
Grains) was 3-4 times as bioavailable as the
P in a near-isogenic normal corn. Additional
studies with growing and finishing pigs indicate
that total dietary P can be reduced by 0.10 to
0.15 of a percentage unit when diets containing
low-phytate corn are fed, which will reduce P
excretion by 30-40%.
- Low-oligosaccharide,
low-phytate soybean meal. Studies
were conducted to assess the bioavailability
on P in low-oligosaccharide, low-phytate soybean
meal (DuPont Specialty Grains) and to assess
its nutritional value when fed in combination
with normal and low-phytate corn. The bioavailability
of P in low-phytate soybean meal was 2-3 times
higher than in normal soybean meal for both pigs
and chicks. Growing pigs fed low-phytate corn
and low-phytate soybean meal with no inorganic
P supplementation had similar performance and
bone strength as pigs fed conventional corn-soybean
meal diets, and they excreted half as much P
in their feces.
- Genetically
modified soybean meal. Studies
have been completed to assess soybean meal
from Roundup Ready® vs isogenic control
soybeans grown under the same environmental
conditions. As expected,
there were no differences in the performance
or carcass traits of the pigs fed the two
diets. Loins are being evaluated by taste
panel. Tissues
from these pigs are being evaluated for
transmission of genetic material (DNA)
and the specific protein
that makes the soybean tolerant to herbicides.
- Bioavailability
of phosphorus in meat byproducts. The
P in meat and bone meal was found to be
considerably higher (~90%) than previously
observed. Ash content
(beef [high ash] vs pork [low ash] origin)
of meat and bone meal had a greater effect
on P
availability (beef>pork) than particle
size or processing temperature, but none
of these
factors affected ileal digestibility of
amino acids.
- Phytase. Phytase
additions were evaluated in corn-soy diets with
normal and low-phytate corn. Phytase was more effective
in diets with normal corn. The effects of phytase
(250, 500, 750 PTU/kg) on digestibility of amino
acids, Ca, and P in soybean meal were assessed
in ileal cannulated pigs. Apparent and true digestibility
of Ca and P, but not amino acids were influenced
by dietary phytase. In another study, formulation
matrix replacement values for graded levels of
phytase were assessed.
- Vitamin
levels for pigs. A
series of studies have examined the potential
of extra vitamin supplementation to enhance performance
of growing-finishing pigs. The increase of a
standard vitamin supplement (that was devoid
of certain vitamins and had various levels of
other vitamins) did not improve growth or carcass
response. Alternatively, graded levels of five
B-vitamins when all other vitamins were present
and when other nutrients were not lacking provided
an improvement in growth, feed efficiency, and
carcass leanness. The response peaked at supplementation
levels above current NRC standards but the study
design did not allow determination of which vitamin(s)
were responsible.
- Betaine
for finishing pigs. In
several experiments, betaine supplementation
improved performance and carcass leanness to
a greater degree in finishing pigs fed a low
energy, corn-soybean meal diet with 20% wheat
middlings than in a corn-soybean meal diet. Betaine
was also assessed in low protein, amino acid
supplemented diets and in crowded pigs. Crowding
(5 and 7 vs 9 sq. ft./pig markedly reduced pig
performance, and betaine did not appear to offset
this depression.
- Diet
manipulation and manure gasses. Studies
were conducted to assess diet manipulation (reduced
protein + amino acids) and various dietary additives
on NH3 and H2S emissions
from manure in simulated anaerobic manure pits.
Dietary protein reduction reduced NH3 emissions
and pH of the slurry. The additives reduced NH3 to
varying degrees. Studies are underway to assess
H2S emissions from manure of pigs
fed low sulfur diets.
- Long-term
antibiotic withdrawal. There
is renewed interest in the antibiotic resistance
area. We continue to periodically monitor resistance
patterns of enteric flora in pigs from a herd
that has not had any exposure to antibiotics
for 25 years and a herd having continuous exposure
to antibiotics.
Sow
Research
- Phytase. Gilts
were used were used to assess fecal P excretion
in late gestation as affected by dietary phytase
additions.
- Enzymes. Sows
have been surgically modified with ileal T-cannulae.
A variety of assessments of digestibility, some
involving enzymes, will be conducted during the
coming year.
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