Feeding value of lentils evaluated for pig diets

Feeding value of lentils evaluated for 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]

SOYBEAN meal is the most widely used protein supplement in swine diets. Soybean meal is superior to other plant-based protein sources in terms of feeding value, and it is the standard to which other protein sources are compared.

Soybeans also contain anti-nutritional factors that are not deactivated during soybean meal processing. These include oligosaccharides (stachyose and raffinose), which can cause excessive gut fermentation, flatulence, diarrhea and reduced nutrient digestibility.

Plant breeders have developed low-oligosaccharide soybean cultivars, but information on their nutritive value is limited for swine, especially when fed as full-fat soybeans.

Lentils are a pulse seed (the edible seeds of leguminous plants having pods, e.g., peas, beans, lentils) that are produced in Canada primarily for human consumption. Lentils contain approximately 25% crude protein and 40% starch and can be used as a protein and energy source in swine diets when not destined for human consumption.

Results from limited research have suggested that lentils can be included in nursery pig diets in amounts of up to 22.5% without reducing growth performance. However, very little information is available on amino acid digestibility and energy values of lentils.

Swine researchers T.A. Woyengo, R. Jha, E. Beltranena, A. Pharazyn and R.T. Zijlstra at the University of Alberta conducted a metabolism study to determine the standardized ileal digestibility (SID) of amino acids and to calculate the net energy (NE) value for two different sources of soybeans and one source of lentils.

This metabolism study used six crossbred barrows weighing approximately 31 kg that were fitted with a T-cannula at the distal ileum. The pigs were housed in individual pens that allowed freedom of movement and were equipped with a dry feeder and a nipple drinker.

The experiment was conducted to obtain six period observations per experimental diet. Each period consisted of nine days: the first five days for adaptation, followed by two days of fecal collection and two days of ileal digesta collection.

Pigs were fed the experimental diets at three times maintenance energy requirements based on bodyweight at the beginning of each period.

The six diets were:

1. Fortified corn starch with soybean meal;

2. Fortified corn starch with regular oligosaccharide micronized full-fat soybeans ground through a 2.8 mm screen hammermill;

3. Fortified corn starch with low-oligosaccharide micronized full-fat soybeans ground through a 2.8 mm screen hammermill;

4. Fortified lentils (red feed-grade) that were not heat-treated but ground through a 2.8 mm screen hammermill;

5. Fortified corn starch (nitrogen free), and

6. Fortified corn starch plus 10% enzymatically hydrolyzed casein (EHC).

The micronization used in diets 2 and 3 involved three steps: (1) soaking soybeans to 18-20% moisture, (2) cooking soaked soybeans with infrared radiant energy at approximately 105 degrees C for 50 seconds and (3) flaking cooked soybeans, followed by steeping and cooling.

The ratio of corn starch to sugar and canola oil in diets 1, 2 and 3 was identical to diet 5 to allow for the calculation of energy digestibility. Diet 6 was fed to pigs to estimate ileal endogenous amino acid losses.

Table 1 summarizes the analyzed composition (on a dry matter basis) of the four feedstuffs used in this study.

Table 2 summarizes the SID of amino acids and apparent total tract digestibility of energy for the four feedstuffs.

The researchers provided the following interpretations of the results:

* The low-oligosaccharide soybeans contained approximately 64% less oligosaccharide than regular soybeans.

* Soybean meal and full-fat soybeans had a similar lysine-to-crude protein ratio.

* Soybean meal and lentils had similar NE values, but lentils were significantly lower in digestible energy than soybean meal.

* The SID of amino acids for soybean meal was greater than for full-fat soybeans and lentils.

* The regular micronized full-fat soybeans had a composition similar to extruded regular soybeans used in other feeding studies.

* The higher tannin content in both full-fat soybeans compared to soybean meal was probably due to the presence of hulls in full-fat soybeans.

* The trypsin inhibitor activity was greater in soybean meal than in micronized full-fat soybeans, so the dietary trypsin inhibitor activity did not affect amino acid digestibility.

* Breeding soybeans for low oligosaccharide content produces full-fat soybeans that have greater sucrose, neutral and acid detergent fiber and trypsin inhibitor activity than regular full-fat soybeans.

* The energy value and amino acid digestibility of full-fat soybeans, whether regular or low oligosaccharide, may not change much because of breeding soybeans for less oligosaccharide.

* Lentils and other pulses can be a good source of energy for swine because of their high starch contents. However, lentils had lower SID of amino acids than soybean meal.

* The SID of most amino acids for lentils was generally lower than for soybean meal, which is probably due to the greater fiber and tannin contents of lentils.

* The regular and low micronized full-fat soybeans had similar NE values and SID of most amino acids but had greater NE values and lower SID of amino acids than soybean meal.

* The amino acids in EHC were nearly 100% digested, implying that EHC can serve to estimate basal ileal endogenous amino acid losses.

 

The Bottom Line

The information from this study indicates that lentils can serve as an alternative pulse feedstuff for swine. Also, the regular and low-oligosaccharide micronized full-fat soybeans were similar in energy and amino acid values for swine.

 

Reference

J. Anim. Sci. Vol. 92, No. 1.

 

1. Analyzed composition (on a dry matter basis) of the four study feedstuffs

 

 

Regular

Low-oligosacc.

 

 

Soybean

micronized full-fat

micronized full-

 

Item

meal

soybeans

fat soybeans

Lentils

Dry matter, %

90.1

92.9

92.8

88.7

Gross energy, Mcal/kg

4.73

5.59

5.59

4.52

Crude protein, %

52.3

43.2

43.4

27.4

Ether extract, %

1.78

19.1

20.6

1.63

Crude fiber, %

3.06

4.50

4.78

4.10

Calcium, %

0.27

0.19

0.28

0.10

Phosphorus, %

0.78

0.58

0.64

0.47

Starch, %

0.19

0.53

0.35

28.6

Lysine, %

3.30

2.76

2.64

1.75

Threonine, %

1.93

1.61

1.60

0.93

Methionine, %

0.70

0.57

0.56

0.19

Tryptophan, %

0.80

0.54

0.61

0.18

Isoleucine, %

2.33

1.96

1.83

1.08

Trypsin inhibitor activity, mg/g

6.21

3.23

4.31

2.48

Tannin, %

0.74

0.87

0.81

0.96

Sucrose, %

6.91

5.31

5.81

Stachyose, %

5.23

1.95

Raffinose, %

0.57

0.14

 

2. SID of amino acids and apparent total tract digestibility of energy

 

 

Regular

Low-oligosacc.

 

 

Soybean

micronized full-fat

micronized full-

 

Item

meal

soybeans

fat soybeans

Lentils

Amino acids

Lysine, %

93.2

76.4

79.2

80.7

Threonine, %

87.9

64.9

68.7

80.5

Methionine, %

94.8

67.7

77.2

87.6

Tryptophan, %

93.4

90.8

87.1

72.9

Isoleucine, %

92.7

63.1

69.3

80.9

Apparent total tract digestibility

Energy, %

94.1

79.5

79.7

86.7

Digestible energy, Mcal/kg dry matter

4.45

4.44

4.45

3.91

NE, Mcal/kg dry matter

2.63

2.95

3.0

2.60

 

Volume:86 Issue:08

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