Pigs utilize different lysine types similarly

Pigs utilize different lysine types similarly

*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, 5810 W. 78th St., Suite 200, Bloomington, Minn. 55439, or email [email protected]

LYSINE in swine diets is primarily supplied by either soybean meal or crystalline lysine, and the efficiency of lysine availability may be affected by the level of feed intake (restricted or ad libitum), individual or group feeding and the pig's gender.

Previous research studies have reported that there were no interactions between the dietary lysine concentration and type of housing (individual versus group feeding) that affected growth traits. However, individually penned pigs had greater feed intakes and growth rates than group-penned pigs.

Results of several studies indicate that gilts require greater dietary amino acid concentrations than barrows because they have a different pattern of lean and fat deposition and a lower feed intake than barrows.

However, in nursery studies, it was demonstrated that there are no differences in lysine needs between barrows and gilts, and the resultant growth was similar whether the pigs were fed soybean meal-bound lysine or crystalline L-lysine.

The results from previous research studies motivated University of Nebraska swine researchers J.J. Colina, P.S. Miller, A.J. Lewis and R.L. Fischer to conduct an experiment consisting of two 4-week trials to determine whether the use of crystalline lysine, from L-lysine hydrochloride, versus bound lysine in soybean meal affected growth and carcass traits in barrows and gilts fed individually or in groups.

The experiment consisted of two replications, each using 112 pigs (half were barrows and the other half were gilts) with an initial bodyweight of 18.6 kg. The pigs were fed individually or in groups of three (14 pigs fed individually and 42 pigs in 14 pens of three) for each replication of barrows and gilts. There were four replications per dietary treatment.

The pigs had ad libitum access to one of seven experimental diets (Table 1) and water for the 28-day experiment. The diets were fortified corn/soybean meal diets with 21.5% dehulled sunflower meal, 2% tallow and corn starch. Corn starch was used as a variable ingredient to balance the diets for amino acids and minerals.

Diets were formulated to be limiting only in standardized ileal digestible (SID) lysine. The other amino acids were calculated to meet National Research Council requirements for SID amino acids for pigs of this weight. Crystalline tryptophan, threonine and methionine were added as needed.

The pigs and feeders were weighed initially and weekly thereafter to determine average daily gain, average daily feed intake and gain:feed. At the end of the experiment, all pigs were scanned for 10th-rib back fat and loin-eye area.

Blood samples were taken weekly from each pig via the jugular vein, centrifuged for plasma and frozen for later plasma and urea nitrogen analysis. Diet samples were analyzed for total amino acids.

Table 2 summarizes the growth performance, SID lysine and carcass traits.

Table 3 summarizes the effect of feeding method and sex on growth performance, SID lysine and carcass traits.

The researchers provided the following interpretations of these results:

* Final bodyweight was affected by the dietary lysine concentration. Pigs fed treatment 1 had the lowest final bodyweight. There were no significant differences in the growth performance criteria for pigs that were supplied lysine from either crystalline lysine or soybean meal.

* Average daily gain and gain:feed increased linearly as the dietary SID lysine concentration increased.

* The daily intake of SID lysine increased linearly as the dietary lysine concentration increased and wasn't different among pigs fed crystalline L-lysine or pigs fed soybean meal.

* Back fat thickness was not different among pigs fed the various dietary treatments, regardless of feeding method or gender.

* A linear increase in loin muscle area was observed in pigs fed treatments 2-4 and 5-7. However, pigs fed treatment 4 had 1.03 sq. cm greater loin-eye area than pigs fed treatment 7.

* Pigs fed crystalline L-lysine had less plasma urea nitrogen than pigs fed soybean meal.

* Pigs fed individually had greater average daily gain and average daily feed intake than pigs fed in groups. The feeding method did not affect gain:feed.

* The daily intake of SID lysine was greater in pigs fed individually versus pigs fed in groups.

* There was no effect of feeding method on carcass traits.

* Feeding method did not affect plasma urea nitrogen. However, the increased plasma urea nitrogen in pigs fed soybean meal reflects the greater crude protein content in these diets. Also, pigs fed individually with dietary lysine from crystalline L-lysine had reduced plasma urea nitrogen compared to pigs fed individually with bound lysine from soybean meal.

* There was no gender effect on growth performance characteristics.

* The similar responses in growth performance to supplemental lysine from either source indicated that the diets were limiting in SID lysine, according to the calculated SID values of the diets and the National Research Council estimates for 20-50 kg pigs, which is 0.83%, or 15.3 g per day.

* Feed intake was not different among barrows and gilts at the bodyweight range of this experiment. The differences in feed intake become more relevant at approximately 35 kg or more.

 

The Bottom Line

This experiment demonstrated that there is no difference in growth performance or carcass characteristics when pigs are fed diets ad libitum supplemented with lysine from crystalline L-lysine or bound lysine from soybean meal.

Also, the responses in growth performance and carcass traits indicate that lysine from either source is used similarly, regardless of feeding method and gender.

 

Reference

J. Anim. Sci. Vol. 91. No. 8.

 

1. Experimental diets

 

SID

Crystalline

Soybean

Metabolizable

Treatment

lysine, %

L-lysine, %

meal, %

energy, kcal/kg

1

0.48

0

7.5

3,030

2

0.56

0.13

7.5

3,014

3

0.65

0.26

7.5

2,999

4

0.74

0.39

7.5

2,983

5

0.56

0

10.8

3,000

6

0.65

0

14.1

2,987

7

0.74

0

17.4

2,964

 

2. Growth performance, SID lysine and carcass traits

 

-Treatment-

Criteria

1

2

3

4

5

6

7

Initial bodyweight, kg

18.71

18.50

18.72

18.37

18.36

19.00

18.45

Final bodyweight, kg

32.43

33.46

35.89

36.51

32.69

36.63

36.18

Average daily gain, kg

0.48

0.52

0.60

0.64

0.52

0.62

0.62

Average daily feed intake, kg

1.29

1.28

1.36

1.36

1.29

1.39

1.32

Gain:feed

0.38

0.41

0.45

0.49

0.40

0.44

0.49

SID lysine intake, g/day

6.30

7.13

8.87

9.91

7.09

9.11

9.62

SID lysine/bodyweight gain, g/kg

13.13

13.70

14.78

15.48

13.63

14.69

15.52

Back fat, cm

1.03

1.03

1.00

0.97

0.99

1.02

0.94

Loin muscle area, sq. cm

12.14

13.45

14.40

15.72

12.81

14.28

14.69

Fat-free lean gain, g/day

200

233

269

302

221

270

287

Plasma urea nitrogen, g/100 mL

32.11

25.71

20.94

14.98

30.58

35.38

36.63

 

3. Effect of feeding method and gender on growth performance, SID lysine and carcass traits

 

-Feeding method-

-Gender-

Criteria

Individual

Group

Barrows

Gilts

Initial bodyweight, kg

18.59

18.58

18.67

18.51

Final bodyweight, kg

35.18

34.47

34.95

34.70

Average daily gain, kg

0.59

0.57

0.57

0.57

Average daily feed intake, kg

1.36

1.29

1.32

1.33

Gain:feed

0.43

0.44

0.44

0.44

SID lysine intake, g/day

8.51

8.06

8.26

8.31

SID lysine/bodyweight gain, g/kg

14.42

14.65

14.49

14.58

Back fat, cm

1.00

0.98

1.01

0.98

Loin muscle area, sq. cm

14.04

13.82

13.58

14.28

Fat-free lean gain, g/day

259

251

245

264

Plasma urea nitrogen, g/100 mL

28.04

28.06

27.40

28.70

 

Volume:85 Issue:39

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