Nucleotides tested in postweaning pig diets

Nucleotides tested in postweaning pig diets

*John H. Goihl is president of Agri-Nutrition Services Inc., Shakopee, Minn. To expedite answers to questions concerning this article, please direct inquiries to Feedstuffs, Bottom Line of Nutrition, 7900 International Dr., Suite 650, Bloomington, Minn. 55425, or email [email protected]

THE process of weaning piglets is a challenging event because of the social, dietary and environmental stresses.

These stresses reduce digestion and absorption of nutrients, increase immune challenges, increase oxidative stress and cause diarrhea, which results in reduced feed intake and growth performance.

Sow's milk contains high levels of nucleotides. There are various nucleotides (e.g., 5'CMP, 5'AMP, 5'GMP and 5'UMP) in sow's milk that are used for maintenance and growth, intestinal development, immune system support and reducing oxidative stress of the piglet. However, typical postweaning diets may contain insufficient nucleotide concentrations.

Therefore, supplemental dietary nucleotides could benefit the health of newly weaned pigs. Also, nucleotide demand increases during periods of stress and rapid growth such as postweaning.

Nucleotides are building blocks of DNA and RNA and serve to carry packets of energy within the cell, play a central role in metabolism and act as co-factors in enzymatic reactions.

Research has shown that one specific nucleotide, 5'IMP, may play a valuable role in nursery diets. This nucleotide is the major one produced during de novo synthesis and serves as a precursor for other nucleotides used for metabolic functions. It has also been shown to increase feed intake by stimulating taste receptors.

Swine researchers A.C. Weaver and S.W. Kim at North Carolina State University hypothesized that dietary supplementation of nucleotides with a high concentration of 5'IMP will enhance pig growth and health during the nursery period.

Therefore, a study was conducted to determine the ability of a supplemental nucleotide mixture high in 5'IMP to enhance pig growth and health postweaning and to measure the impact of nucleotides on blood levels of immunological and oxidative stress parameters.

The study used 120 piglets that were weaned at approximately 22 days of age and weighed approximately 7.3 kg.

The pigs were housed in temperature-controlled, raised-deck nursery pens. Each pen had a double-space feeder and two nipple water drinkers for three pigs per pen. The pigs were blocked by weight and sex and were randomly allotted to four treatments (Table 1).

Each treatment had 10 replications for a total of 30 pigs per treatment. Pigs were provided feed and water ad libitum.

Bodyweight and feed intake were measured every seven days during the 28-day trial. Pigs were fed a typical phase I diet for seven days and a phase II diet for 21 days.

Blood samples were collected from the jugular vein from one pig per pen at the end of each dietary phase. The plasma was separated and analyzed for immune and oxidative stress responses. Immunoglobulins A, G and M and the cytokine tumor necrosis factor (TNF) were used to measure the immune response as indicators of health status. Oxidative DNA damage was estimated by determining the concentration of plasma 8-OHdG, a metabolite of DNA breakdown.

Diarrhea scoring for all pigs was determined on days 5, 8 and 15 by determining the moisture content of the feces. Diarrhea scores used were: 1.0 for normal/firm, 1.5 for loose feces/slight diarrhea, 2.0 for moderate liquid consistency, 2.5 for definite diarrhea with unformed fluid feces and 3.0 for severe diarrhea with very watery and frothy feces.

Table 2 summarizes the 28-day growth performance.

The results, as interpreted by the researchers, showed that the average daily gain and average daily feed intake increased with increasing nucleotide supplementation to the diet.

Table 3 summarizes the measured immune and oxidative stress parameters.

The results, according to the researchers' interpretation, showed no difference among treatments at seven days on test for the immunological and oxidative stress measurements. However, at 28 days on test, the immune system was altered by the nucleotide supplementation. Immunoglobulin A was significantly lower, at 0.2 and 0.5, and immunoglobulin M was significantly lower, at 0.5, compared to the other treatments.

The levels of TNF tended to decrease linearly as the nucleotide level was increased in the diet. The lowest level of 8 OHdG was at the 0.5 level of nucleotide supplementation.

Table 4 summarizes the fecal scores. The researchers indicated that the fecal scores of diarrhea severity were not different among treatments on days 5 and 15. However, fecal scores tended to be the lowest for treatment 3 on day 8, which coincided with the change from the phase I diet to the phase II diet.

Even though research has shown that the 5'CMP nucleotide is provided in weaning pig diets, the other nucleotides are not provided in adequate amounts by typical feedstuffs used in nursery diets. Therefore, newly weaned pigs may not be able to synthesize or consume sufficient amounts of nucleotides to meet the demand for optimum growth and health.

The variations in performance reported in previous studies may be related to the type and levels of nucleotides supplemented in the diet. Also, the dietary supplementation of nucleotides showed some ability to reduce diarrhea, which is part of maintaining piglet health.

Studies have shown that high levels of the nucleotide 5'IMP improve feed intake in pigs postweaning and may also increase total nucleotide concentrations because of the metabolic conversions to 5'IMP, which also serves as a precursor to the formation of other nucleotides.

 

The Bottom Line

The results of this study demonstrated the importance of nucleotides in the diets of weaned piglets for growth performance and health. Additional research is needed under differing swine production practices to determine the optimal levels and type of nucleotides.

 

Reference

J. Anim. Sci. Vol. 92. No. 2.

 

1. Treatments for 28-day trial

Treatment

Nucleotide additive*, g/kg

1

0.0

2

0.2

3

0.5

4

1.0

*Inotide — contains 53.0% total nucleotides (51.0% 5'IMP and 2.0% other nucleotides), 16.8% crude ash, 11.2% total sugars, 9.3% water, 4.1% phosphorus, 3.2% total amino acids and 2.4% compounds containing non-protein nitrogen.

 

2. 28-day growth performance

 

-Treatment-

Criteria

1

2

3

4

Bodyweight, initial, kg

7.25

7.27

7.27

7.27

Bodyweight, 28 day, kg

15.10

14.87

15.43

16.03

Avg. daily gain, g/day

270.9

261.2

279.1

301.8

Avg. daily feed intake, g/day

412.5

433.5

436.7

480.2

Gain:feed

0.656

0.602

0.637

0.629

 

3. Immune and oxidative stress parameters

 

-Treatment-

Criteria

1

2

3

4

7 days on test

 

 

 

 

Immunoglobulins A, G and M, mg/mL

8.86

8.47

7.16

8.64

TNF, picograms/mL

94.42

91.17

81.67

89.92

8-OHdG, mg/mL

1.44

1.65

1.29

1.29

28 days on test

 

 

 

 

IgA, G and M, mg/mL

8.50

9.04

8.30

9.43

TNF, picograms/mL

126.67

99.58

98.17

85.58

8-OHdG, mg/mL

0.54

0.40

0.36

0.41

 

4. Fecal scores

 

-Treatment-

 

1

2

3

4

Day 5

1.07

1.11

1.11

1.15

Day 8

1.33

1.12

1.03

1.26

Day 15

1.48

1.26

1.35

1.45

 

 

Volume:86 Issue:12

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