Save energy, feed costs with dietary emulsifier

Save energy, feed costs with dietary emulsifier

Nutritional emulsifiers can be used to improve fat digestibility and, thus, energy efficiency for high-performing animals.

*Marc Rovers is with Orffa/Excentials in the Netherlands.

ENERGY is a major cost component in diets for high-performing animals. Due to their high energy density, fats and oils are important energy sources in feed formulation. Improving the energy efficiency of these raw materials is of much interest from an economical point of view.

Nutritional emulsifiers can be used to improve fat digestibility and, thus, improve energy efficiency, which will result in a lower feed cost and contribute to more economical and sustainable animal production.

 

Fat digestion

The terms fat and oil (or lipid) refer to triglycerides of several profiles of fatty acids. Fatty acids that are not bound to other organic components as glycerol are the so-called free fatty acids. Lipids constitute the main energetic source for animals, and they have the highest caloric value among all nutrients.

The amount of energy an animal can obtain from dietary fat depends on the fat digestibility. A higher digestibility will result in more available energy. The fat digestion by animals is related to different characteristics of the fat and the absolute amount of fat added to the diet.

Animal factors such as age also influence fat digestibility. Young birds have a low level of natural lipase production and a low rate of bile salt production and, therefore, have limited fat digestion. Fat digestion can be enhanced by adding emulsifiers to the diet.

Fat digestion occurs in a few steps. Initially, large fat globules are emulsified in the watery environment of the gut, aided by peristaltic movement. Normally, fat and water do not mix, and therefore, bile salts assist in this mixing process as a natural emulsifier. Smaller fat droplets are formed to increase the contact surface for the lipase enzyme. This enzyme is produced by the pancreas and breaks down fat.

Fats and oils are esters of three fatty acids and glycerol. The fatty acids are released (hydrolyzed) from the glycerol by lipase. This results in two fatty acids and one monoglyceride.

The next step is the formation of micelles. Micelles are water-soluble aggregates of lipid molecules containing both polar and non-polar groups. The molecules are grouped in the micelles in such a way that the polar groups are on the outside in contact with the aqueous phase, while non-polar parts form the inner lipid core of the micelles.

Bile salts and monoglycerides aid as emulsifiers in the formation of micelles. When the micelles come into contact with the micro villous membrane, they are disrupted, and the fatty acids can be absorbed by the lipophilic cell membrane. The process of fat digestion is illustrated in Figure 1.

 

Nutritional emulsifiers

Bile salts are natural emulsifiers. The monoglycerides that are formed after hydrolysis of the fat also act as emulsifiers. Nevertheless, the capacity of these natural emulsifiers can be a limiting factor for fat digestion.

Young animals produce a limited amount of bile salts, and therefore, fat digestibility is limited in the early stage of life. On the other hand, the characteristics of the dietary fat can restrict its digestibility. Fatty acid mixtures with high amounts of free fatty acids lack the formation of monoglycerides and, therefore, have a lower emulsifying capacity.

Long-chain unsaturated fatty acids and monoglycerides form micelles promptly, whereas saturated fatty acids have a reduced ability to form micelles because of their characteristic low polarity. These characteristics of the fat explain the difference in digestibility. In general, saturated fatty acids (mostly found in animal fat) are digested less easily than unsaturated fatty acids (like vegetable fat).

High levels of free fatty acids also limit digestibility. Exogenous nutritional emulsifiers can assist in improving fat digestibility. Obviously, the positive effect of adding such emulsifiers is more pronounced for less-digestible fats than for very highly digestible fats. The effect will also be more pronounced at higher levels of added fat. Nevertheless, in all cases, even with highly digestible fats, positive effects have been observed.

 

Importance of HLB balance

An emulsifier is a molecule with a water-soluble (hydrophilic) part and a fat-soluble (lipophilic) part. The combination of these two components in one molecule gives it the unique property that the emulsifier can dissolve as well in fat as in water and can aid in mixing the two fractions.

Different types of emulsifiers are commercially available. When choosing an emulsifier, the principle of hydrophilic-lipophilic balance (HLB) is important. HLB assigns a value to how fat or water soluble a product is. The scale ranges from zero to 20. The lower the HLB value, the more lipophilic or fat soluble the emulsifier becomes; the higher the HLB, the more water soluble or hydrophilic the emulsifier will be (Figure 2).

The objective of using an emulsifier determines whether a low or a high HLB is more suitable. Ideally, the emulsifier should be soluble in the continuous phase (rule of Bancroft). When a small amount of water is mixed into a fat-rich environment, a lower HLB is advised (fat-soluble emulsifier). If a small amount of fat is mixed into an aqueous environment, an emulsifier with a higher HLB is advised (water-soluble emulsifier).

In the case of a nutritional emulsifier, a limited amount of fat is added to the watery environment of the gut. A bird consumes 1.5-2.0 times more water than feed, and the feed has only a small amount of fat, so the amount of water is much higher than the amount of fat in the intestine. In this case, a high HLB is more suitable.

Orffa/Excentials has introduced a nutritional emulsifier with a very high HLB (Excential Energy Plus) — much higher than that of emulsifiers such as lecithin and lysolecithin (Figure 2). Because of this high HLB, the efficacy in terms of improving fat digestibility is very high.

Save energy, feed costs with dietary emulsifier

 

Animal trials

Several experiments were set up to demonstrate the effect of emulsifiers on fat digestibility in broilers.

In the first experiment, four different emulsifiers — all nutritional emulsifiers and all with relatively high HLB values — were added to the diet at a dose of 250 g per ton. All four emulsifiers increased fat and energy digestibility, and this resulted in a higher apparent metabolizable energy (AMEn) value of the diet. Emulsifier B (Excential Energy Plus) had the highest fat digestibility and an energy upgrade of almost 140 kcal (Table 1).

A second experiment tested if it is possible to formulate a diet with a lower energy content and compensate for this lower energy content with a very high-HLB emulsifier.

This was tested in two different basal diets with different fat compositions. Diet 1 had a traditional fat composition. Diet 2 had a high level of saturated fatty acids and a high level of free fatty acids. The results of experiment 2 for the overall period are summarized in Table 2.

The diets with reduced energy and the addition of the emulsifier performed at the same level as the control diets. The production performances show that the addition of the emulsifier was able to compensate for a 5.3% lower energy content.

 

Save energy, cost

The addition of a very high-HLB nutritional emulsifier to a diet can compensate for a reduction in dietary energy. What does this mean for the practical farmer? If a diet can be formulated with a lower energy content, this means less addition of expensive fats and oils and, as a result, a lower cost.

The extent of this effect on cost depends on nutritional constraints in the formula and on raw material prices, which will differ between regions and will vary over time.

To give an insight into the magnitude of the effect, a typical broiler diet was formulated with different energy levels. In Table 3, the effect on diet cost is shown. From this practical example, it can be concluded that lowering the basal diet from 3,150 kcal to 3,050 kcal will reduce the inclusion of oil and fat. This leads to a cost reduction of more than $10 per metric ton.

 

Conclusion

Energy is a major cost component in diets for high-performing animals. Nutritional emulsifiers can be used to improve fat digestibility and, thus, energy efficiency. From a practical point of view, this means that nutritionists are able to formulate diets with a lower energy content and keep the same performance. This will result in lower feed costs and contribute to more economical and sustainable animal production.

 

1. Digestibility of fat, crude protein (CP) and gross energy (GE) and energy content (AMEn) of broiler diets

 

-Digestibility, %-

-AMEn-

Upgrade from

Broiler diet

Fat

CP

GE

MJ/kg DM

kcal

control, kcal

Control

63.0a

56.9a

68.3a

13.17a

3,147a

Emulsifier A

68.5b

60.1d

71.1b

13.71b

3,276b

129

Emulsifier B

70.5b

59.8cd

71.3b

13.74b

3,283b

137

Emulsifier C

68.6b

58.2ab

70.5b

13.60b

3,250b

103

Emulsifier D

67.6ab

58.6bc

71.2b

13.75b

3,285b

138

a,b,c,dSuperscripts differ at P < 0.05.

 

2. Performances during the overall period (0-39 days)

 

-Diet 1-

-Diet 2-

Fat composition

-High U/S ratio, low FFA*-

-Low U/S ratio, high FFA-

Energy level (ME)

Basal

-5.3%

Basal

-5.3%

Very high-HLB nutritional emulsifier

No

Yes

No

Yes

Weight at day 39, g

2,675

2,630

2,657

2,714

Avg. daily gain, days 0-39, g/day

67.5

66.3

67.0

68.5

WAFCR1500** (day 26)

1.549

1.546

1.505

1.504

WAFCR2500** (day 39)

1.464

1.505

1.493

1.507

*U/S = unsaturated/saturated fatty acids; FFA = free fatty acids.

**WAFCR = weight-adjusted feed conversion.

 

3. Cost price of typical broiler diet (grower, days 10-30) formulated with different ME constraints

ME (kcal/kg)

3,050

3,100

3,150

3,200

Cost price of diet ($/mt)

395

401

408

414

% added fat

3.7

4.8

5.9

7.1

% total fat

5.6

6.7

7.8

8.8

% cereals

68

67

65

64

% soybean meal

25.3

25.5

25.7

25.8

 

Volume:85 Issue:46

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