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Departments of Animal Science and
Food Science, North Carolina State University, Raleigh, NC 27695-7621 and
*
Department of Animal Science & Technology, Seoul National University, Suweon, Korea 441–744
3To whom correspondence should be addressed.
 |
ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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KEY WORDS: • pigs • carnitine • biosynthesis • nitrogen balance • body composition
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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for review). Given that carnitine is a cosubstrate
of carnitine palmitoyltransferase, a pivotal regulatory enzyme in the
pathway of fatty acid oxidation, carnitine status could conceivably
affect utilization of fatty acids as metabolic fuel. This has led to
interest and unsubstantiated claims among athletes and
body-builders in the use of carnitine to enhance performance
(Heinonen 1996
). Similarly, interest in production
agriculture has stemmed from the desire to partition nutrients away
from fat accretion and toward muscle deposition. Several studies in a
variety of species have reported improved nitrogen (N) balance, reduced
body fat and/or increased protein accretion upon
L-carnitine supplementation (Bohles et al. 1984b
, Hongu and Sachan 2000
, Ji et al. 1996
, Penn et al. 1997
, Rabie and Szilagyi 1998
); however, the limited studies evaluating
carnitine effects in growing pigs (Cho et al. 1999
,
Hoffman et al. 1993
, Owen et al. 1996
)
have yielded inconsistent results.
Although biosynthesis of carnitine in the liver and kidney
appears sufficient for the metabolic needs of mammalian adults
(Rebouche and Seim 1998
), dietary carnitine is necessary
to maintain normal carnitine concentration in the newborn
(Borum 1983
). Indeed, the capacity of fatty acid
oxidation in neonatal pigs (Coffey et al. 1991
,
Kempen and Odle 1993
, 1995
, Wolfe et al. 1978
) depends on L-carnitine supply.
However, it is not known how well growing mammals can synthesize
carnitine de novo nor how dependent they are on carnitine supplied by
the diet. In typical swine husbandry, pigs make a transition from a
mixed-ingredient neonatal diet (containing various animal products)
to a strict vegetarian diet (i.e., a corn-soy– based diet, devoid of
animal products) at ~7–8 wk of age. Therefore, we chose to study
pigs at this age on the basis of the supposition that removal of
dietary carnitine sources (animal products) might occur while pigs were
not fully competent with respect to de novo carnitine biosynthesis.
To test the hypothesis that dietary carnitine can alter nutrient
partitioning in young growing pigs, we designed and fed basal diets
[i.e., low metabolizable energy
(ME)4
/lysine with restricted intakes] such that N retention and protein
accretion would respond to ME. Furthermore, diets were formulated to
contain 7% fat on the supposition that supplemental carnitine would
improve ME derived from fat (Fig. 1
.). Congruent with this hypothesis, the data reported herein will show
that carnitine reduced urinary N excretion, increased protein accretion
and reduced carcass fat.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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All animal procedures were approved by the IACUC of North Carolina
State University. Pigs (n = 25; 17.9 ± 0.1
kg; 54 ± 1 d of age) were used in five identical metabolic
trials (5 pigs/trial) to study the interactive effects of
L-carnitine and protein level on N and carnitine balance.
Pigs (PIC genotype) were obtained from the Lake Wheeler Field
Laboratory of North Carolina State University and fed corn-soybean
meal diets (9 or 12 g lysine/kg diet) containing either 0 or 500
mg/kg added L-carnitine (2 x 2 factorial, randomized
complete block design). Diets were formulated to contain 14.24 MJ ME/kg
diet and 40 g/kg supplemental soy oil, and to exceed requirements for
vitamins and minerals (NRC 1988
) as shown in Table 1
. The low protein diet was marginally adequate in protein, containing
0.63 g lysine/MJ ME. The high protein diet contained 0.84 g
lysine/MJ ME. The diets were supplemented with crystalline amino acids
to provide the same optimal ratios of essential amino acids
(Chung and Baker 1992
) to that of lysine.
|
Pigs were placed into metabolism cages (0.77, 1.27 and 0.85 m in
width, depth and height, respectively). After 5 d of adaptation to
the 1.2% lysine diet without L-carnitine, pigs (~54 d of
age) were allocated to experimental diets, and a 10-d nitrogen balance
trial was conducted. The amount of feed offered was based on NRC (1987)
formulas and previous measurements of ad libitum intakes
of pigs during the adaptation period. To further ensure energy
restriction, diets were offered at 85% of estimated ad libitum
intakes. This also resulted in rapid and complete feed intake. All pigs
were fed 400 g of diet twice (at 0800 and 2000h) on d 1 of
each metabolic trial, and the amount of feed per day was increased by
50 g every 2 d. Feed consumption was monitored along with
total excretion of feces and urine. Urine was collected into a plastic
bucket containing 30 mL of 6 mol/L HCl. A 50-mL aliquot of daily urine
was stored at 4°C until the last day of the trial and was
subsequently frozen at -20°C. Ferric oxide (0.25 g/100 g diet) was
used as a marker to identify feces from the initial meal of the
collection period. Total feces were collected daily, placed in aluminum
trays and stored at 4°C. At the end of the test, total feces were
desiccated in a 55°C air-forced drying oven. Fecal collections
were subsampled and ground through a 1-mm screen, weighed and stored in
plastic bags. Fecal and urine samples were analyzed for N by the
micro-Kjeldahl procedure (AOAC 1990
). Apparent
nitrogen balance was computed as the difference between consumption and
excretion.
Body composition analysis.
At the beginning of each replicate of the metabolic trial, one pig was
selected randomly and killed for measurement of initial empty body
composition [percentage of protein, lipid and ash; AOAC (1990)
]. At the end of each metabolic trial, (pig age = 64 d), all pigs were killed by electrocution. Except for the
contents of the gastrointestinal tract and bladder, and small tissue
biopsies taken, the entire carcass was ground once through a 15-mm
diameter plate, twice through a 9-mm plate and then twice through a
3-mm plate. Subsamples of the final mixture were taken and stored at
-20°C until they were analyzed for dry matter, ash, crude protein
(micro-Kjeldahl), crude fat, total carnitine and energy content.
Chemical analysis was conducted on each sample in duplicate. From the
chemical analysis, the total amounts of protein, lipid, ash and
moisture were determined for each pig on an empty body weight basis.
Thus, the initial carcass composition was subtracted from the
composition determined at d 64 of age. Daily protein and lipid
accretion rates were calculated as the difference between final (d 64
of age) and initial (d 54 of age) composition, divided by 10 d.
Blood sampling.
Blood samples were obtained in heparinized tubes by vena cava puncture, 2–3 h after feeding on the last morning of each balance trial. Blood samples were centrifuged at 2300 x g for 25 min within 1 h of collection. Plasma samples were stored at -20°C and analyzed for free carnitine by a radioenzymatic method.
Carnitine analysis.
[1-14C]acetyl-CoA was purchased from American
Radiolabeled Chemicals (St. Louis, MO). Scintillation fluid
(Scintisafe) and Resin (AG 1 x 8, 100–200, chloride form) were
obtained from Fisher Scientific (Fair Lawn, NJ) and Bio-Rad
Laboratories (Richmond, CA), respectively. Acetyl-CoA, carnitine
acetyltransferase (EC 2.3.1.7) and other chemicals were purchased from
Sigma Chemical (St. Louis, MO). All samples were prepared by the
procedure modified from Bhuiyan et al. (1992)
. Weighed
subsamples of diet, and ground body tissue were homogenized in
appropriate volumes of water using a PowerGen Homogenizer (Model 700,
Fisher Scientific, Atlanta, GA; 4 x 10 s at 30,000
rpm). Those mixtures and urine were alkalized with KOH and
incubated for 1 h at 60°C before treatment with
HClO4. Then, the supernatant was neutralized for total
carnitine assay. Free plasma carnitine and total carnitine of the
samples described above were assayed by the enzymatic radioisotope
method of McGarry and Foster (1976)
, modified as
described by Bhuiyan et al. (1992)
. Carnitine
concentrations of samples were corrected by blanks without
acetylcarnitine transferase that were measured for each sample type and
determined by using a standard concentration curve. The average
recovery of free carnitine and total carnitine was 99 and 90%,
respectively (data not shown).
Statistical analysis.
All data were analyzed as a randomized complete block design with a 2
x 2 factorial (L-carnitine x protein level)
arrangement of treatments using the General Linear Models procedure of
SAS (1989)
. The statistical model included 4 df for
replicate, and l df each for L-carnitine, protein level and
the interaction between L-carnitine and protein level. In
addition, daily N excretion data were analyzed as above with an
additional split-plot in time (Steel et al. 1997
).
This daily-excretion statistical model included 12 df for
whole-plot error (trial x protein level x L-carnitine) and 4 df each for protein x time and
carnitine x time interactions. The experimental unit was the
individual pig in all statistical analyses. The relationships between
tissue carnitine and nutrient accretion were determined by regression
analysis. Significant differences and relationships were accepted at
P < 0.1.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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High protein feeding increased average daily gain (ADG) (P
< 0.01, Table 2
) by 34%, and L-carnitine supplementation increased ADG by
7.3% (P < 0.10). High protein feeding improved N
digestibility (P < 0.01) by 4.4% and N retention
(P < 0.01) by 5.2%, but increased urinary N excretion
by 29% (P < 0.01). Carnitine reduced urinary N
excretion by 14% (P < 0.10) and improved the
biological value (defined as the percentage of absorbed N retained in
the body) by 3.3% (P < 0.05). No interactions were
detected between L-carnitine and protein level
(P > 0.10).
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Carnitine supplementation increased daily urinary carnitine excretion
(P < 0.01) linearly over time, but neither carnitine
nor high protein feeding had any effect on daily fecal carnitine
excretion (data not shown). High protein feeding had negligible effects
on urinary or fecal daily carnitine excretions. Dietary
L-carnitine reduced daily urinary nitrogen excretion after
3 d of supplementation (P < 0.01, Fig. 2A
). High protein feeding maintained higher daily urinary N excretion for
the entire experimental period (P < 0.05). Neither
L-carnitine nor high protein feeding affected daily fecal N
excretion (P > 0.10, Fig. 2B
).
|
Body composition data showed that the percentage of fat in the carcass
decreased when L-carnitine was supplemented (P
< 0.10), but the proportions of crude protein (CP) and moisture
were not affected by either high protein feeding or
L-carnitine (P > 0.10, Table 3
). Body ash percentage was reduced by high protein feeding (P
< 0.05). Carnitine concentration in carnitine-supplemented
pigs was almost 100% higher than in control pigs (P < 0.01). High protein feeding increased CP accretion by 33%
(P < 0.01) and moisture accretion by 38%
(P < 0.01), but did not affect (P > 0.10) fat or ash accretion. Carnitine supplementation increased the CP
accretion rate by ~10% (P < 0.10), and increased
the carnitine accretion rate 4.5-fold (P < 0.01).
There were no interactions between L-carnitine and protein
level (P > 0.10).
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There were positive correlations between plasma free carnitine, body
carnitine (Fig. 3A
, r2 = 0.726, P < 0.001) and urinary carnitine excretion (not shown). Deviate
relationships between plasma free carnitine and protein accretion rate
for the two protein levels are shown in Figure 3B
. Protein
accretion rate was positively correlated with plasma free carnitine in
pigs fed high protein diets (r2 = 0.500, P < 0.023), but not in pigs fed low protein
diets (r2 = 0.001, P
= 0.92). Muscle carnitine concentration was positively correlated
with protein accretion rate only in pigs fed high protein diets
(r2 = 0.457, P < 0.032, Fig. 3C
).
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Studies evaluating L-carnitine effects on growth
performance in young pigs (Cho et al. 1999
,
Hoffman et al. 1993
, Owen et al. 1996
)
have reported variable findings. Cho et al. (1999)
observed no appreciable improvement in the performance of 21-d-old pigs
when 1000 mg/kg carnitine was supplemented into diets containing 17%
dried skim milk. Owen et al. (1996)
reported that
supplementation of 500 mg/kg L-carnitine improved feed
efficiency by 9% in pigs from d 36 to 57 of age when pigs were fed a
corn-soybean meal-dry whey diet containing 5% soy oil. This
improvement stemmed from reduced feed intake rather than increased ADG,
suggesting that pigs fed L-carnitine may improve energy
utilization from soy oil, but that control pigs fed no
L-carnitine may satisfy their energy requirement by
increasing feed intake. Hoffman et al. (1993)
reported
that supplemental L-carnitine or soybean oil did not affect
ADG, energy or nitrogen utilization in young pigs. Because pigs in
these experiments were allowed ad libitum access to feed, energy status
was likely high enough to maintain ADG regardless of dietary carnitine.
On the other hand, we suggest that energy limitation in our study
(i.e., low ME/lysine treatment and 85% ad libitum consumption)
accentuated energy utilization from dietary fat, and thus nitrogen
utilization was affected. The improved biological value of nitrogen in
the carnitine-supplemented group suggests that more dietary amino
acids were used for body protein synthesis rather than for energy.
Collectively, these observations show that carnitine improved nitrogen
utilization under ME-limited conditions.
Nutrient accretion and body composition.
Owen et al. (1996)
found that carcass lipid and daily
lipid accretion were reduced, but carcass protein and daily protein
accretion were unaffected by L-carnitine supplementation in
weaning pigs. A similar trend was found in older pigs (Owen et al. 1993
and 1994
) in that L-carnitine improved
carcass characteristics (i.e., reduced lipid accretion rate and backfat
thickness) and feed efficiency, but did not affect ADG in
growing-finishing pigs. By contrast, lipid accretion was not
reduced, but daily protein accretion was increased in our study. This
discrepancy is possibly due to differences in energy status and lysine
to ME ratio between the two experiments. Owen et al. (1996)
offered diets containing 5% soy oil ad libitum to
weaning pigs from 6 to 20 kg. Even if the
L-carnitine–supplemented group might have increased
ß-oxidation, decreased lysine degradation and improved ME for protein
synthesis, the unsupplemented group could have increased lysine and ME
available for protein synthesis by increasing feed intake (i.e., ad
libitum consumption). Therefore, it is possible that
L-carnitine did not affect daily protein accretion and ADG,
but decreased average daily feed intake in their research. In
contrast, we offered 85% of estimated ad libitum energy intake (0.63
or 0.84 g lysine/MJ ME for the low protein or high protein level,
respectively) to growing pigs from 18 to 22 kg. Lower energy status (by
restriction) was implemented to amplify putative
L-carnitine effects on protein accretion. With this
constraint, two possible mechanisms are plausible. One is that
L-carnitine increased ß-oxidation of fatty acids and
supplied more ME for protein synthesis. The other is that lysine
degradation was reduced by the increased ME from fat such that more
dietary amino acids could be directed toward protein synthesis. The
latter is supported by the increase in the biological value of N
observed when L-carnitine was supplemented in the present
study. Increased daily protein accretion and reduced body fat
composition due to L-carnitine supplementation support both
possibilities. Bohles et al. (1984b)
reported similar
findings in that L-carnitine supplementation of
mini-pigs during total parenteral nutrition with lipid emulsion
increased lipolysis, oxidation of fatty acids, energy gain from infused
fat and N balance. In particular, the branched-chain amino acids in
the muscle of the miniature piglets were increased with
L-carnitine (Bohles et al. 1984a
). In a
similar manner, Ji et al. (1996)
concluded that
L-carnitine altered intermediary metabolism and reduced
body fat without changing growth rate in Atlantic salmon.
Even though pigs fed both of our basal diets were marginally restricted
in daily ME, the high protein diet was relatively more restricted by a
low ME/lysine ratio. Indeed, this was evidenced by the higher urinary N
excretion from amino acid degradation in pigs fed the high protein
diet. For this reason, it was expected that the addition of
L-carnitine to the high protein diet would preferentially
improve growth performance and nutrient accretion rate compared with
that in low protein level. Even though the responses to carnitine in
the high protein diet were larger than those from the low protein diet,
no significant interaction (protein level x L-carnitine) was detected for any criteria by ANOVA. This
implies that pigs fed the low protein diet also were restricted
sufficiently in daily ME for L-carnitine to affect all
criteria in this study. Regression analysis (Fig. 3B and
C
), however, did support deviate responses for the two
protein levels, with greater apparent responses to carnitine in the
high protein diet compared with the low protein diet. Taken together,
our data support the hypothesis that supplemented
L-carnitine improves the efficiency of nitrogen utilization
by 20-kg pigs fed fat-containing diets that are limited in ME.
Thus, L-carnitine increased rate of gain in general and
protein accretion rate in particular.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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2 Supported in part by the North Carolina
Agriculture Research Service, Raleigh, NC, the Ministry of Agriculture
& Forestry-SGRP/HTDP in Korea, and the Algroup Lonza, Fair Lawn, NJ.
4 Abbreviations used: ADG, average daily gain; CP,
crude protein; ME, metabolizable energy.
Manuscript received December 14, 1999. Initial review completed February 7, 2000. Revision accepted March 9, 2000.
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REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
1. Association of Official Analytical Chemists Official Methods of Analysis 15th ed. 1990 AOAC Arlington, VA.
2. Bhuiyan A.K.M.J., Jackson S., Turnbull D. M., Aynsley-Green A., Leonard J. V., Bartlett K. The measurement of carnitine and acyl-carnitines: application to the investigation of patients with suspected inherited disorders of mitochondrial fatty acid oxidation. Clin. Chim. Acta 1992;207:185-204[Medline]
3. Bohles H., Michalk D., Brandl U., Fekl W., Borresen H. C., Stehr K. The effect of L-carnitine supplemented total parenteral nutrition on tissue amino acid concentrations in piglets. J. Nutr. 1984a;114:671-676
4.
Bohles H., Segerer H., Fekl W. Improved N-retention during L-carnitine-supplementated total parenteral nutrition. J. Parent. Enteral Nutr. 1984b;8:9-13
5. Borum P. R. Carnitine. Annu. Rev. Nutr. 1983;3:233-259[Medline]
6. Cho W. T., Kim J. H., Bae S. H., Han I. K., Han Y. K., Heo K. N., Odle J. Effects of L-carnitine with different lysine levels on growth and nutrient digestibility in pigs weaned at 21 days of age. Asian-Australas. J. Anim. Sci. 1999;12:799-805
7. Chung T. K., Baker D. H. Ideal amino acid pattern for ten kilogram pigs. J. Anim. Sci. 1992;70:3102-3111[Abstract]
8. Coffey M. T., Shireman R. B., Herman D. L., Jones E. E. Carnitine status and lipid utilization in neonatal piglets fed diets low in carnitine. J. Nutr. 1991;121:1047-1053
9. Heinonen O. J. Carnitine and physical exercise. Sports Med 1996;22:109-132[Medline]
10. Hoffman L. A., Ivers D. J., Ellersieck M. R., Veum T. L. The effect of L-carnitine and soybean oil on performance and nitrogen and energy utilization by neonatal and young pigs. J. Anim. Sci. 1993;71:132-138[Abstract]
11.
Hongu N., Sachan D. S. Caffeine, carnitine and choline supplementation decreases body fat and serum leptin concentrations as does exercise. J. Nutr. 2000;130:152-157
12. Ji H., Bradley T. M., Tremblay G. C. Atlantic salmon (Salmo salar) fed L-carnitine exhibit altered intermediary metabolism and reduced tissue lipid, but no change in growth rate. J. Nutr. 1996;126:1937-1950
13. Kempen T.A.T.G. v., Odle J. Medium-chain fatty acid oxidation in colostrum-deprived newborn piglets: stimulatory effect of L-carnitine supplementation. J. Nutr. 1993;123:1531-1537
14. Kempen T.A.T.G. v., Odle J. Carnitine affects octanoate oxidation to carbon dioxide and dicarboxylic acids in colostrum-deprived piglets: in vivo analysis of mechanisms involved based on CoA- and carnitine-ester profiles. J. Nutr. 1995;125:238-250
15. McGarry J. D., Brown N. F. The mitochondrial carnitine palmitoyltransferase system from concept to molecular analysis. Eur. J. Biochem. 1997;244:1-14[Medline]
16. McGarry J. D., Foster D. W. An improved and simplified radioisotopic assay for the determination of free and esterified carnitine. J. Lipid Res. 1976;17:277-281[Abstract]
17. National Research Council Predicting Feed Intake of Food Producing Animals 1987 National Academic Press Washington, DC.
18. National Research Council Nutrient Requirements of Swine 9th ed. 1988 National Academic Press Washington, DC.
19. Owen K. Q., Nelssen J. L., Goodband R. D., Weeden T. L., Blum S. A. Effect of L-carnitine and soybean oil on growth performance and body composition of early-weaned pigs. J. Anim. Sci. 1996;74:1612-1619[Abstract]
20. Owen K. Q., Smith J. W., II, Nelssen J. L., Goodband R. D., Tokach M. D., Friesen K. G., Blum S. A. The effect of L-carnitine on growth performance and carcass characteristics of growing-finishing pigs. J. Anim. Sci. 1994;72(suppl. 1):274(abs.)
21. Owen K. Q., Weeden T. L., Nelssen J. L., Blum S. A., Goodband R. D. The effect of L-carnitine additions on performance and carcass characteristics of growing-finishing swine. J. Anim. Sci. 1993;71(suppl. 1):62(abs.)
22. Penn D., Bobrowski P. J., Zhang L., Schmidt-Sommerfeld E. Neonatal nutritional carnitine deficiency: a piglet model. Pediatr. Res. 1997;42:114-121[Medline]
23. Rabie M. H., Szilagyi M. Effects of L-carnitine supplementation of diets differing in energy levels on performance, abdominal fat content, and yield and composition of edible meat of broilers. Br. J. Nutr. 1998;80:391-400[Medline]
24. Rebouche C. J., Seim H. Carnitine metabolism and its regulation in microorganisms and mammals. Annu. Rev. Nutr. 1998;18:39-61[Medline]
25. SAS Institute Inc. SAS/STAT User’s Guide version 6 ed. 1989 SAS Institute Cary, NC.
26. Steel R.G.D., Torrie J. H., Dickey D. A. Principles and Procedures of Statistics: A Biometrical Approach 1997 McGraw-Hill New York. NY.
27. Wolfe R. G., Maxwell C. V., Nelson E. C. Effect of age and dietary fat level on fatty acid oxidation in the neonatal pig. J. Nutr. 1978;108:1621-1634
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