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Animal Science Research Report AL73-2 Florida Agricultural
March 1973 Experiment Station
Gainesville, Florida

UTILIZATION OF NON-PROTEIN NITROGEN BY YOUNG SWINE -

G. E. Combs and H. D. Wallace

The relatively high cost of swine diets constantly stimulates research

to find more economical feed ingredients for lower production costs. Although

most reports show negative results, interest still remains high on the use of

non-protein nitrogen (NPN) as one possible means of reducing the cost of

expensive protein.

The present study was conducted to evl1Wl 'tuop_4 Ar heidiets of

young swine.

Experimental

Thirty six pigs were allotted to 6 gtty treatments from outcome
,... Cuiv. 01 Fjoridato
groups formed on the basis of weight and li'ter. ""."..'.-"" '

All pigs were fed a protein-free depletion diet for a 2 week period.

Following this depletion period the pigs were given the following treat-

ments for 4 weeks.

Treatment No. 1 2 3 4 5 6

Total dietary protein % 18 16 14 22 22 22
Soybean meal protein % 18 16 14 18 16 14
NPN protein % 0 0 0 4 6 8

1/ Other articles on this subject include Ani. Sci. Mimeo Series 70-12.
Data used in the article came from Experiment 179-C.
2/ Combs and Wallace, Animal Nutritionists, Department of Animal Science,
University of Florida.
Duophos (diammonium phosphate) supplied by International Minerals and
Chemical Corp.
This public document was promulgated at an annual cost of
$ 148.98 or .14898cents per copy to inform county agricul
tural directors, ranchers and growers of research results
in swine management and nutrition.

Department of Animal Science
Institute of Food and Agricultural Sciences

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At the end of the 4-week feeding period pigs on treatments 1,2 and 3 were

given treatments 4,5 and 6 and those on 4,5 and 6 switched to 1,2 and 3,

respectively.

Blood samples were taken at the end of the depletion period and

periodically throughout the repletion period for determination of blood urea

nitrogen, total serum protein and albumin:globulin ratio.

All pigs were self-fed in an enclosed, concrete-floored building.

Water was furnished by automatic watering devices.

Composition of the semi-purified diets is presented in table 1.

Results and Discution

A summary of the results is presented in table 2.

When compared to diets that contained 18, 16 or 14% protein from soybean

meal the presence of NPN at any level depressed rate of gain. The comparison

of feed intake data at all protein levels, with and without NPN, also shows

that NPN decreased feed intake.

In general the depressing action of NPN on rate and efficiency of gain

was illustrated quite well during the 14 day period in which the feeding of

NPN and non-NPN diets was switched. Growth rate and feed efficiency was

depressed by dietary NPN and increased by the feeding of the non-NPN diets.

Blood urea nitrogen values (BUN) tended to reflect the presence of

dietary NPN whereas total serum protein and albumin:globulin ratio were in-

effective indicators. Blood samples taken during the 1st, 2nd and 4th re-

pletion weeks showed significantly (P <0.5) higher BUN values with pigs

fed diets containing 2,4 or 8% NPN. When the diets were switched BUN

values continued to reflect the presence of dietary NPN.

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Summary

Thirty six pigs were fed a nitrogen-free depletion diet for 2 weeks

then given access to semi-purified diets with and without 4,6 or 8% NPN

from diammonium phosphate.

After a 4 week feeding period rate and efficiency of gain was

significantly (P <.05) depressed by addition of NPN.

Blood urea nitrogen but not total serum protein or albumin:globulin

ratio appeared to reflect the presence of dietary NPN.

These data indicate that in the presence of adequate or marginal

levels of dietary protein from soybean meal, NPN should not be added to

starter diets.

Table 1.Composition Of Diets

Diet No. 1 2 3 4 5 6
Item

Cerelose 26.98 28.98 30.98 25.70 26.81 27.92
Cane sugar 26.97 28.97 30.97 25.69 26.80 27.91
Corn oil 5.00 5.00 5.00 5.00 5.00 5.00
Duophos 3.56 5.34 7.12
Soybean meal 36.00 32.00 28.00 36.00 32.00 28.00
Limestone 2.00 2.00 2.00
Defluorinated phos. 3.00 3.00 3.00 -
Salt .50 .50 .50 .50 .50 .50
Trace mineral mix 1/ .10 .10 .10 .10 .10 .10
Vitamin mix / 3.20 3.20 3.20 3.20 3.20 3.20
Aureo S-P 250 .25 .25 .25 .25 .25 .25

1/ Provided the following (ppm): Mn, 57; Fe, 70; Cu, 48; Co, 1.6; K, 7.5
and Zn, 100.
2/ Supplied vitamin A, 1000 I.U.; vitamin D, 200 I.U.; niacin, 36 mg.;
riboflavin, 8 mg.; pantothenic acid, 16 mg.; choline, 400 mg.;
thiamin 0.6 mg.; pyridoxine, 0.5 mg.; vitamin B12, 10 mcg. per pound
of diet.

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Summary

Thirty six pigs were fed a nitrogen-free depletion diet for 2 weeks

then given access to semi-purified diets with and without 4,6 or 8% NPN

from diammonium phosphate.

After a 4 week feeding period rate and efficiency of gain was

significantly (P <.05) depressed by addition of NPN.

Blood urea nitrogen but not total serum protein or albumin:globulin

ratio appeared to reflect the presence of dietary NPN.

These data indicate that in the presence of adequate or marginal

levels of dietary protein from soybean meal, NPN should not be added to

starter diets.

Table 1.Composition Of Diets

Diet No. 1 2 3 4 5 6
Item

Cerelose 26.98 28.98 30.98 25.70 26.81 27.92
Cane sugar 26.97 28.97 30.97 25.69 26.80 27.91
Corn oil 5.00 5.00 5.00 5.00 5.00 5.00
Duophos 3.56 5.34 7.12
Soybean meal 36.00 32.00 28.00 36.00 32.00 28.00
Limestone 2.00 2.00 2.00
Defluorinated phos. 3.00 3.00 3.00 -
Salt .50 .50 .50 .50 .50 .50
Trace mineral mix 1/ .10 .10 .10 .10 .10 .10
Vitamin mix / 3.20 3.20 3.20 3.20 3.20 3.20
Aureo S-P 250 .25 .25 .25 .25 .25 .25

1/ Provided the following (ppm): Mn, 57; Fe, 70; Cu, 48; Co, 1.6; K, 7.5
and Zn, 100.
2/ Supplied vitamin A, 1000 I.U.; vitamin D, 200 I.U.; niacin, 36 mg.;
riboflavin, 8 mg.; pantothenic acid, 16 mg.; choline, 400 mg.;
thiamin 0.6 mg.; pyridoxine, 0.5 mg.; vitamin B12, 10 mcg. per pound
of diet.

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Table 2. Performance Of Pigs Fed Diets Containing
Various Levels Of NPN

Treatment No. 1 2 3 4 5 6
Total Dietary Protein 18 16 14 22 22 22
NPN % 0 0 0 4 6 8

Initial weight,lb.
Weight after 2 wk. depletion, lb.
eight after 28 days on treatment,
Wv. daily gain, 28 day period, lb.
kv. daily gain, 14 days on
switched diets

kv. daily feed intake, lb.:
28 day test period
14 day switched diet period

Feed/gain, lb.:
28 day test period
14 day switched diet period

Blood urea nitrogen:
End 2 week depletion
1 week repletion
2 week repletion
4 week repletion
2 week diet switch

Total serum protein:
End 2 week depletion
1 week repletion
2 week repletion
4 week repletion
2 week diet switch

Albumin:Globulin ratio:
End 2 week depletion (1:
1 week repletion
2 week repletion
4 week repletion
2 week diet switch

11.5
11.6
44.7
1.18a

11.5
11.6
42.1
1.09ab

1.41 0.89

1.92 1.75
.3.45 2.94

1.63 1.60
2.45 3.30

4.0
10.7b
11.4ac
16.8a
23.8a

4.5
4.9
5.5
5.9
6.1

1.21a
1.23
1.48
1.51
1.35

4.2
9.2ab
11. 6ac
15.4a
23.6a

4.4
4.5
5.3
5.5
5.9

1.32a
1.31
1.89
1.50
1.34

11.5
11.9
39.6
0.99abc

0.62

1.71
2.53

1.73
4.08

4.7
7.2a
8. 8a
15.8a
24.9a

4.3
5.1
5.4
5.8
5.8

1.29a
1.23
1.01
1.25
0.99

11.4
11.3
36.6
0.91bc

1.30

1.53
2.47

1.68
1.90

4.0
16.1c
19.8bc
23.8b
15.0b

4.8
4.8
4.8
5.8
6.2

1.56ab
1.41
1.52
1.33
1.25

11.4
11.9
35.8
0.85c

11.4
11.4
30.1
0.67d

1.45 1.59

1.20 1.39
3.58 4.25

1.41 2.07
2.47 2.67

3.5
16.5c
17.3ac
26.5b
18.9b

4.5
4.6
5.1
6.2
6.2

1.48ab
1.19
1.15
1.13
1.14

3.9
20.9d
18.0bc
26.4b
20.0b

5.6
4.9
5.3
6.1
6.0

2.41b
1.10
1.42
0.89
1.12

3acO Means on same line bearing different superscript
(P < .05).

letters differ significantly