Volume 10, Issue 4: 150-157; July 27, 2020  
THE USE OF PREDICTED APPARENT METABOLIZABLE ENERGY  
VALUES TO UNDERSTAND THE OIL AND FAT VARIABILITY IN  
BROILERS  
Agnes THNG, Jun Xiang TING, Hui Ru TAY, Chin Yi SOH, Hwee Ching ONG, David TEY  
Kemin Industries (Asia) Pte Limited, Animal Health and Nutrition, 12 Senoko Drive, Singapore 758200, Singapore  
*Email: agnes.thng@kemin.com  
ABSTRACT: The objective of this study was to analyze the predicted apparent metabolizable energy (AME) of  
different oil samples across Asia Pacific region and investigate the AME values in broilers of different ages (< 21  
or > 21 days old). A total of 635 oil and fat samples consisting of 93 fish oils, 36 coconut oils, 70 crude palm  
oils, 42 refined palm oils, 43 soybean oils, 147 rice bran oils, 163 tallows and 41 lards were collected and  
analyzed over a span of eight years (2011 to 2018). The free fatty acid (FFA) content of oil and fat samples were  
analyzed through acid-base titration and the degree of saturation (ratio of unsaturation to saturated fatty acids;  
U:S) were determined with Gas Chromatography with Flame Ionization Detector (GC-FID). The FFA and U:S of the  
samples were then incorporated into the Wiseman equation to correlate the oil and fat qualities with the AME.  
Our survey revealed AME variations were prevalent in most of the oil types studied, with fish oils and tallows  
showing the largest energy gap within oil samples. The results showed that the predicted AME values for oil and  
fat samples differ across countries, even within batches from the same supplier. Taken together, our  
investigation suggests that there is a considerable variation in the AME values of oils and fats, which may affect  
the feed formulation precision.  
Keywords: Dietary energy, Fatty acid composition, Lipids, Oil quality, Poultry  
INTRODUCTION  
Vegetable oils and animal fats are usually added to animal diets to increase dietary energy concentration (Ravindran et  
al., 2016). Since oils and fats confer at least twice as much energy as other food nutrients such as carbohydrates and  
proteins (Ahiwe et al., 2018; Blair, 2018), there is a greater demand in optimizing the use of these products to meet the  
energy requirements of poultries (Ravindran et al., 2016). Furthermore, high fat feeding in poultry has been proven to  
improve the digestibility and absorption of non-lipid constituents (Blair, 2018). However, the quality of oils and fats are  
highly variable, and their digestibility are dependent on their chemical structures (Codony et al., 2017). Poor processing  
and storage conditions can also cause structural changes in oils and fats, leading to high fluctuations in the nutritional  
Fat digestion consists of the emulsification of dietary fat with bile salt, followed by the enzymatic hydrolysis of  
triglycerides. The 2-monoglycerides, formed from partial hydrolysis of triglycerides, improve the solubility and absorption  
of free fatty acids through the formation of micelles (Pond et al., 2004; Scanes et al., 2019). As such, low levels of 2-  
monoglycerides will result in incomplete micellar solubilization of free fatty acids. It was previously reported that the total  
micellar fatty acids were lowest in the duodenum of free fatty acid (FFA) fed chicks where monoglycerides were present  
at trace level (Hofmann and Borgstrom, 1962; Sklan, 1979). In addition, fat digestion is also highly dependent on the  
degree of fatty acid saturation where Tancharoenrat et al. (2014) reported a higher digestibility with unsaturated fatty  
acids such as oleic acid and linoleic acid in comparison to saturated fatty acids such as palmitic and stearic acids.  
Additionally, the natural emulsifying properties of unsaturated fatty acids could also aid in mixed micelle formation and  
absorption, resulting in better utilization of saturated fatty acids (Rodriguez-Sanchez et al., 2019). Given the importance of  
FFA and the degree of saturation of oil (ratio of unsaturated to saturated fatty acids; U:S) in oil digestion and absorption,  
the Wiseman equation incorporates both of these parameters into one general equation to predict the energy values of  
different sources of oils and fats (Wiseman and Blanch, 1994).  
As these macromolecules are important energy sources for animals, it is imperative for us to understand the  
variation of oil quality based on apparent metabolizable energy (AME) across countries and oil types, and its impacts on  
broilers. Previous reports showed that the fat utilization in broilers was age dependent where fat utilization improved with  
age (Rodriguez-Sanchez et al., 2019). Animal nutritionists often struggle to formulate feed with adequate energy intake  
due to the variation of the nutritional values in oil and fat samples that can lead to reduction in the performances of the  
150  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
animals and substantial economic losses (Niu et al., 2009; Ahiwe et al., 2018). A better understanding of the AME of  
different oil and fat samples can be gained by incorporating the FFA and U:S data into the Wiseman equation to generate  
information on the quality of the oil and fat samples; this will allow nutritionists to make informed decisions on their use  
for feed formulation to achieve consistent animal performance. In this study, the AME for oil and fat samples were  
determined based on the Wiseman equation to highlight the importance of accurate information on dietary energy value  
of feed.  
MATERIALS AND METHODS  
Instrumentation  
DL 50 GRAPHIX auto-titrator (Mettler-Toledo, Ohio, United States) and DG113-SC glass electrode (Mettler-Toledo)  
were used to determine free fatty acid content. 7890B GC-FID (Agilent Technologies, California, United States) with  
Supelco SPTM-2560 (L × I.D. 100 m × 0.25 mm, df 0.20 μm thickness) (Sigma-Aldrich, Missouri, United States) was used  
for chromatographic separation of fatty acid methyl esters (FAME).  
Sample collection and preparation  
A total of 635 oil and fat samples with plant and animal origins were collected across the Asia Pacific region and  
analyzed over a span of eight years from year 2011 to 2018. These samples included tallow, rice bran oil, fish oil, palm oil  
(crude and refined palm oil), soybean oil, lard and coconut oil. All samples were stored in plastic containers upon receipt  
and kept in the chiller at 2 °C to 6 °C. Before analysis, the samples were either thawed at room temperature or melted in  
the oven at 60 °C. All samples were analyzed within one week from the collection date.  
Free Fatty Acid (FFA) content  
The FFA content of oil and fat samples were determined with an in-house method, modified from the Association of  
Official Analytical Chemists (AOAC) method (AOAC, 2012). Fifty (50) mL of 95% ethanol (Aik Moh Paints and Chemical Pte  
Ltd, Singapore) was added to 1.0 g of oil or fat sample in a titration cup. The sample was stirred for 60 s under stirring  
speed of 50% with an auto-titrator. After stirring, titration was done with 0.1 N sodium hydroxide (Merck KGaA,  
Darmstadt, Germany) as the titrant using a pH sensor with measurement mode set as equilibrium controlled. The result  
was calculated from the volume consumption of the sodium hydroxide titrant and its concentration. Based on the oil type,  
the FFA content is expressed either as % oleic acid, % palmitic acid or % lauric acid.  
Fatty Acid Methyl Esters (FAME) composition analyses  
FAME composition of oil and fat samples were determined using an in-house method, with modification from  
Association of Official Analytical Chemists (AOAC) method (AOAC, 2012). Four mL of 2% (w/v) methanolic sodium  
hydroxide (Merck) was added to 40 mg of fat or oil sample and refluxed until there were no visible fat globules. 5 mL of  
14% boron trifluoride in methanol (Sigma-Aldrich) was added and refluxed for another 2 mins. Finally, 10 mL of heptane  
(Sigma-Aldrich) was added and refluxed for another 1 min. Subsequently, the content was cooled to room temperature.  
Next, 15 mL of 26% (w/v) sodium chloride (Merck) was added and swirled vigorously. The top organic layer (heptane) was  
filtered through sodium sulphate (Merck) and injected into the GC-FID for chromatographic separation. Extracted samples  
were analyzed with helium at a flow rate of 0.85 mL/min as carrier gas and a split ratio of 40:1. Injection volume was set  
at 0.4 µL with injection port temperature set at 260 °C. The GC oven temperature was programmed at 140 °C for the first  
5 mins and raised to 235 °C at 5 °C/min for 15 mins, followed by 15 °C/min to 250 °C for 5 mins. The total run time  
was 45 mins. Percentage composition of each FAMEs in oil and fat samples were calculated with Supelco 37 component  
Fatty Acid Methyl Esters (FAME) Mix certified reference material (CRM) (Sigma-Aldrich) as reference standard.  
Data analysis  
Prediction of Apparent Metabolizable Energy (AME) using Wiseman equation  
AME of samples were predicted using a general equation (Equation 1) with A, B, C and D based on the values shown  
AME (MJ/kg fat) = A + B*FFA + C*eD(U/S)  
(1)  
Apparent Metabolizable Energy (AME) variation  
AME range was calculated as the difference between the highest and lowest predicted AME values whereas relative  
variations were calculated as the ratio of calculated range against lowest predicted AME or literature AME.  
Statistical analyses  
Single measurement data were calculated for the AME of each oil type. Descriptive statistics were calculated using  
Microsoft Excel 365 and presented in Table 3.  
151  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
Table 1 Empirical values of constants A D used in Wiseman equation to predict the apparent metabolizable energy  
(AME) values of poultry at different ages  
Constant (unit)  
Young broilers (< 21 days)a  
Old broilers (> 21 days)a  
A (MJ/kg)  
B (MJ/kg)  
38.112 ± 1.418  
-0.009 ± 0.002  
39.025 ± 0.557  
-0.006 ± 0.001  
C (MJ/kg)  
D
-15.337 ± 2.636  
-0.506 ± 1.186  
-8.505 ± 0.746  
-0.403 ± 0.088  
a Empirical values of constants A D were categorized into two groups, young broilers (aged < 21 days) and old broilers (aged > 21 days). All  
young broilers (aged < 21 days) followed the same empirical values for constants A D, likewise for old broilers (aged > 21 days).  
RESULTS  
Predicted Apparent Metabolizable Energy (AME) values for all samples  
Using GC-FID and acid-base titration, all samples were analyzed for their lipid composition and FFA content  
(Table 2). Descriptive analysis of eight different oil types were presented in Table 3. AME of young broilers  
(aged < 21 days) and old broilers (aged > 21 days) were studied in this paper. Based on the GC-FID analyses, it was  
determined that the U:S for crude palm oil was lowest amongst all samples analyzed while the U:S for soybean oil was the  
highest, with relatively low FFA content of 1.01% oleic acid recorded (Table 3). When the data was further extrapolated  
using Equation 1, it was found that the highest predicted mean AME values were from soybean oil, at 8362 kcal/kg  
(young broilers) and 8672 kcal/kg (old broilers). On the other hand, the lowest predicted mean AME values were from  
crude palm oil with the predicted AME values at 6617 kcal/kg (young broilers) and 7669 kcal/kg (old broilers) (Table 3).  
It was apparent that the predicted AME values were inconsistent across all oil samples. In particular, a large spread  
of AME for fish oil samples for different age groups of broilers was observed. The energy gaps for young (< 21 days old)  
and old broilers (> 21 days old) were 2295 kcal/kg and 1417 kcal/kg, with a relative variation of 36% and 19%  
respectively (Table 3). The AME gap for crude palm oil for young (< 21 days old) and old broilers (> 21 days old) were  
found to be 1057 kcal/kg and 540 kcal/kg with relative variations of 17% and 7% (Table 3). Comparatively, refined palm  
oil also showed a smaller AME spread relative to crude palm oil, with 506 kcal/kg for young broilers (8% variation) and  
250 kcal/kg for old broilers (3% variation) (Table 3). As the three major oil groups (e.g. tallow, rice bran oil, and fish oil)  
accounted for 63% of the total oil and fat samples collected and represented the majority of the oil and fat products  
(Table 2), the data for these groups were further analyzed (Table 4).  
Tallow  
Large AME discrepancy of 2670 kcal/kg for young broilers with relative variation of 49% and 1565 kcal/kg for old  
broilers with a relative variation of 23% were observed (Table 3). Out of 163 samples, 85% of the samples were received  
from five different sources originating from South Korea (Table 4). Majority of the samples were from the same source,  
supplier 1, where it accounted for approximately 78% of the tallow samples received from South Korea. Large spread of  
AME was observed for supplier 1, at 1248 kcal/kg with a relative variation of 20% for young broilers and 626 kcal/kg  
with a relative variation of 8% for old broilers (Figure 1). As such, supplier 1 from South Korea was singled out with  
samples collected in eight batches over a span of five years, from year 2012 to 2016. The AME values observed were  
inconsistent even within batches where the energy spread was in the range of 230 kcal/kg to 1063 kcal/kg with relative  
variation of 3% to 17% (Table 5). Likewise, AME values for tallow samples from supplier 3 were inconsistent as well, with  
energy spread at 1362 kcal/kg for young broilers (aged < 21 days) and 740 kcal/kg for old broilers (aged > 21 days)  
(Figure 1). This translated to relative variations of 20% for young broilers (aged < 21 days) and 10% for old broilers (aged  
> 21 days).  
Rice bran oil  
All rice bran oil samples received were from Thailand since 2012. From 2012 to 2014, the predicted ME values  
were highly variable as shown in Figure 2. However, from 2015 onwards, the predicted AME values were calculated to be  
more consistent where the energy values ranged from 7500 kcal/kg to 8000 kcal/kg (relative variation of 7%) with only  
seven outlier samples. High FFA content of 12.50% oleic acid was observed (Table 3).  
Fish oil  
Majority of the fish-based oil samples were from Indonesia and Thailand (63% of fish oil samples). Figure 3 showed  
that fish oils from Thailand consisted of large energy gaps of 2295 kcal/kg (young broilers) and 1417 kcal/kg  
(old broilers). Similarly, when the AME for different batches of fish oils from the same supplier (supplier A) in Thailand  
were determined, it was found that the AME ranged from 6442 kcal/kg to 8738 kcal/kg with relative variation of 36% in  
young broilers (Table 4). Likewise, a difference of 1926 kcal/kg in terms of AME variation (30%) was observed between  
fish oil samples from Indonesia (Table 4).  
152  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
DISCUSSION  
The quality and efficiency of feed formulations are highly dependent on two main factors, the extent and accuracy of  
animal nutritionists’ knowledge on raw materials’ qualities and compositions, as well as the nutrient requirements of  
targeted species (Lall and Dumas, 2015). Animal nutritionists struggle to formulate feed with adequate energy when lipid  
energy values stated in traditional feed tables often deviate from the actual energy value due to various reasons such as  
poor storage and processing conditions. It is also likely that these values did not account for the species and age  
dependent metabolism. While Baião et al. (2005) reported that the AME for tallow was in the range of 7000 kcal/kg,  
Figures 1(A) and 1(B) indicated that regardless of animal age groups, inconsistency in AME values of tallow were  
apparent where energy variations occurred even within the same supplier with relative variation as high as 17% for the  
same batch of tallow samples. Without proper lipid quality evaluations, this will eventually lead to poorer animals’  
performances and economic losses.  
The predicted mean AME of soybean oil is the highest as compared to other oil types. One of the main contributing  
factors is the presence of high unsaturated fatty acids where the recorded U:S ratio was 4.71 (Table 3). Consistent to a  
previous study conducted by Rodriguez-Sanchez et al. (2019) where it was reported that hydrolysis in unsaturated diets  
were relatively more efficient than saturated diets which results in higher digestibility and absorption. The AME of  
soybean oil ranged from 6665 kcal/kg to 8796 kcal/kg for young broilers (aged < 21 days) and 7716 kcal/kg to  
8997 kcal/kg for old broilers (aged > 21 days). In comparison, a study showed that the AME of soybean oil is at 8790  
kcal/kg (Baião et al., 2005), demonstrating 12% relative variation from the literature value. Low fatty acid content  
(1.01% oleic acid) was also observed for soybean oil. The presence of high FFA decreases bile secretion which in turns  
reduces micellar formation, leading to poor absorption of digested materials (Ravindran et al., 2016; Rodriguez-Sanchez  
et al., 2019). A study conducted by Wiseman and Salvador (1991) showed that AME is inversely proportional to the FFA  
content, with the effect being more pronounced in younger broilers. In agreement with the study conducted by Wiseman  
and Salvador, our survey also showed that the AME values of young broilers were more divergent as compared to older  
broilers, demonstrating their sensitivity to oil quality variations possibly due to less developed physiological capacity in fat  
Our results showed that from year 2015 onwards, the AME values for rice bran oil samples collected from Thailand  
were more consistent (Figure 2). One plausible reason could be due to technological improvements made to the  
manufacturing or transporting processes in Thailand. While more consistent AME values were observed over the years,  
the FFA content of rice bran oil remains the highest among the eight oil types analyzed (Table 3). As rice bran contains  
endogenous lipase capable of digesting and hydrolyzing the triglycerides present to form FFA (Goffman and Bergman,  
2003, Vallabha et al., 2015), it is possible that the samples collected were likely to be extracted from poor quality rice  
bran where the triglycerides had been hydrolyzed (Rajan and Krishna, 2009). Interestingly, while high FFA content was  
observed in rice bran oil (Table 3), its AME remains one of the highest among the other oil types. One of the reasons could  
be due to the relatively higher U:S where the presence of unsaturated fats aid in the solubilization and absorption of FFA  
Large energy gaps were observed in fish oil with 36% variation in young broilers (< 21 days) and 19% variation in old  
broilers (> 21 days). This is likely due to the presence of different fish oils with different oil quality grades such as salmon  
fish oil and crude tuna fish oil. There are different standards for different fatty acid compositions of different fish origins.  
For instance, while the standard for C22:6 (n-3) docosahexaenoic acid of tuna oil ranges from 21.0 42.5% of total fatty  
acids, similar standard for wild salmon oil ranges from 6.0 14.0% (FAO/WHO, 2017). Fish oils are also susceptible to  
lipid oxidation due to the high degree of unsaturation (European Food Safety Authority (EFSA, 2010) where unsaturated  
fatty acids are prone to oxidation (Dominguez et al., 2019). Comparatively, refined palm oil has lower AME spread as  
compared to crude palm oil. This is likely due to the refining processes that may have possibly removed the impurities,  
and therefore confers a more consistent oil quality in refined palm oil.  
Given these analyses, it is evident that having a proper lipid analysis in place is fundamental for accurate estimation  
of dietary energy in feed formulations.  
Table 2 Number of oils and fats collected across Asia Pacific region, per oil type  
Oils and fats  
Tallow  
Count  
163  
147  
93  
Rice bran oil  
Fish oil  
Crude palm oil  
Soybean oil  
Refined palm oil  
Lard  
70  
43  
42  
41  
Coconut oil  
36  
153  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
Table 3 Descriptive analysis data of the eight different oil types for broilers  
Apparent Metabolizable Energy (AME) of poultry (broiler)  
Crude palm oil Soybean oil Refined palm oil  
Tallow  
Rice bran oil  
Fish oil  
<21  
Lard  
Coconut oil  
Item  
<21  
>21  
<21  
>21  
>21  
<21  
>21  
<21  
>21  
<21  
>21  
<21  
>21  
<21  
>21  
Statistics (kcal/kg)  
Minimum  
Maximum  
Range  
5448  
8118  
2670  
6742  
6949  
7087  
6886  
29  
6930  
8495  
1565  
7744  
7853  
7913  
7820  
15  
6709  
8138  
1429  
7608  
7710  
7787  
7635  
38  
7566  
8503  
937  
6442  
8738  
2295  
6912  
7183  
7916  
7370  
60  
7530  
8947  
1417  
7826  
7965  
8373  
8076  
34  
6359  
7416  
1057  
6509  
6601  
6674  
6617  
21  
7524  
8064  
540  
6665  
8796  
2131  
8321  
8579  
8589  
8362  
49  
7716  
8997  
1282  
8624  
8807  
8814  
8672  
43  
6533  
7038  
506  
7652  
7902  
250  
6002  
7825  
1822  
6996  
7115  
7347  
7084  
62  
7399  
8320  
922  
6685  
7914  
1229  
7159  
7493  
7664  
7411  
54  
7705  
8375  
670  
1st quartile  
8332  
8488  
8567  
8194  
12  
7616  
7666  
7704  
7669  
11  
6858  
6908  
6964  
6886  
18  
7810  
7835  
7862  
7824  
9
7878  
7934  
8060  
7925  
31  
7926  
8121  
8229  
8075  
32  
Median  
3rd quartile  
Mean  
SE of mean  
374  
191  
265  
147  
581  
329  
172  
88  
463  
279  
114  
56  
398  
200  
323  
192  
Standard deviation,  
Nutritional parameters  
FFA (%)a  
2.66  
1.28  
12.50  
2.70  
4.62  
2.14  
7.07  
1.10  
1.01  
4.71  
0.34  
1.20  
1.35  
1.48  
8.45  
2.10  
U:S ratio  
a
< 21 = Young broilers of age less than 21 days; > 21 = Old broilers of age more than 21 days; SE = Standard error; FFA = Free fatty acid content; U:S = unsaturated: saturated fatty acid. Free fatty acid  
content is expressed as % palmitic acid for crude and refined palm oil, % lauric acid for coconut oil and % oleic acid for the rest of the oil types.  
Table 4 Details of samples collected from the different countries for the three major oil types (Tallow, rice bran oil and fish oil), with minimum, maximum, range and mean  
apparent metabolizable energy (AME) of young broilers (< 21 days)  
Oil types  
Tallow  
Rice bran oil  
Fish oil  
AME (< 21 days) (kcal /kg)  
AME (< 21 days) (kcal/kg)  
AME (< 21 days) (kcal/kg)  
Country  
Min  
-
Max  
-
R
-
Mean  
-
n
0
ns  
-
Min  
Max  
8138  
R
1429  
Mean  
7635  
n
147  
ns  
7
Min  
Max  
R
Mean  
7367  
n
25  
ns  
5
Thailand  
6709  
6442  
8738  
2295  
Indonesia  
Vietnam  
-
-
-
-
0
2
-
-
-
-
-
-
0
0
-
-
6499  
6575  
7919  
7199  
7440  
7948  
7861  
-
8425  
8321  
8233  
7199  
7826  
7948  
8309  
-
1926  
1746  
313  
0
7416  
7103  
8028  
7199  
7633  
7948  
8031  
-
34  
24  
3
4
9
1
1
1
1
1
-
6299  
5448  
5826  
6002  
6240  
6073  
6503  
5448  
6333  
6561  
6372  
6640  
8118  
6520  
6503  
8118  
35  
6316  
5989  
6138  
6345  
-
-
-
-
Philippines  
Singapore  
Taiwan  
1112  
546  
638  
1878  
448  
0
6
1
1
2
5
2
1
12  
-
-
-
-
0
-
3
-
-
-
-
0
-
1
10  
-
-
-
-
0
-
386  
0
2
South Korea  
7003 138  
-
-
-
-
0
-
1
New Zealand  
India  
6370  
6503  
3
1
-
-
-
-
0
-
448  
-
3
-
-
-
-
0
-
0
Total  
2670  
6886 163  
6709  
8138  
1429  
7635  
147  
7
6442  
8738  
2295  
7370  
93  
23  
AME (< 21 days) = Apparent metabolizable energy for young broilers of age less than 21 days; Min = Minimum; Max = Maximum; R = Range; n = number of observations; nS = number of suppliers.  
154  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
Table 5 Details of tallow samples collected from South Korea, Supplier 1, with minimum, maximum, range  
calculated for apparent metabolizable energy (AME) of young broilers (< 21 days)  
AME (< 21 days) (kcal/kg)  
Percentage  
variation (%)  
Count  
Min  
Max  
R
Batch  
Batch 1  
Batch 2  
Batch 3  
Batch 4  
Batch 5  
Batch 6  
Batch 7  
Batch 8  
26  
7
6240  
6546  
6612  
6710  
6630  
7258  
7173  
6908  
7303  
7124  
7428  
7488  
7413  
7258  
7173  
7137  
1063  
578  
815  
778  
783  
0
17  
9
24  
22  
18  
1
12  
12  
12  
NA  
NA  
3
1
0
9
230  
AME (< 21 days) = Apparent metabolizable energy for young broilers of age less than 21 days; Min = Minimum; Max = Maximum; R = Range;  
NA = Not Applicable  
Figure 1 - Variations in minimum, first quartile, median, third quartile and maximum in predicted apparent  
metabolizable energy (AME) for both (A) young broilers (aged < 21 days) and (B) old broilers (aged > 21 days)  
differentiated by the different tallow suppliers in South Korea.  
Figure 2 - Predicted apparent metabolizable energy (AME) trend graph for young broilers (aged < 21 days) with  
emphasis on year 2015 onwards, for rice bran oils.  
155  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
Figure 3 - Variations in minimum, first quartile, median, third quartile and maximum in predicted apparent  
metabolizable energy (AME) for both (A) young broilers (aged < 21 days) and (B) old broilers (aged > 21 days)  
differentiated by the different fish oil suppliers in Thailand.  
CONCLUSION  
In conclusion, our data suggested that there is a considerable variation of the AME values in oils and fats. The AME  
variation that existed across oil samples from different regions and even within batches from similar suppliers may affect  
the feed formulation precision if the variation remains unaccounted for. Generic lipid energy values extracted from the  
traditional feed table were typically inaccurate as the animal species and age dependent metabolism were likely not  
considered in these tables. Furthermore, poor storage and processing conditions may deteriorate the oil quality as well.  
Inevitably, inconsistent AME values will not only contribute to huge economic losses but may also impact the animal  
performances adversely due to inaccurate feed formulations that fail to meet the caloric requirements of the animals. In  
view of these concerns, it is important to have a proper lipid evaluation tests in place for a more accurate lipid profile (e.g.  
AME value) estimation. Additionally, oil quality parameters such as peroxide and p-anisidine values should also be  
considered for oxidative stability evaluation as oil and fat quality may deteriorate over time. To improve oil and fat  
qualities, bio-emulsifiers and antioxidants can be used concurrently to improve oil and fat qualities in the context of  
oxidative stability and feed fat variability control.  
DECLARATIONS  
Corresponding Authors  
Agnes Thng, e-mail: agnes.thng@kemin.com. Jun Xiang Ting, email: junxiang.ting@kemin.com. Hui Ru Tay, email:  
Authors’ Contribution  
A. Thng proposed the design of study, prepared the manuscript and performed the laboratory analysis. J.X. Ting, H.R.  
Tay, C.Y. Soh and H.C. Ong assisted with the laboratory analyses. D. Tey reviewed and edited the manuscript.  
Conflict of interests  
The authors declared that there is no conflict in this study.  
Acknowledgements  
The authors thank the suppliers from the Asia Pacific region for the collection of oil and fat samples. We also thank  
Dr C. Sugumar for his scientific contributions in this study, and Ms R.Lye, Drs J. Tan, K.P. Chan and H. Chirakkal for their  
constructive feedbacks on the manuscript draft. This study was supported by Kemin Industries (Asia) Pte Limited, Animal  
Health and Nutrition.  
REFERENCES  
Ahiwe E, Omede AA, Abdallh MEB and Iji PA (2018). Managing dietary energy intake by broiler chickens to reduce production costs and improve  
product quality. IntechOpen, London, UK, pp 115 145. Google Books I ResearchGate  
AOAC (2012). Association of Official Analytical Chemists. Official method of analysis, 19th Edition. Washington D.C. pp. 12.  
AOAC (2012). Association of Official Analytical Chemists. Official method of analysis, 19th Edition. Washington D.C. pp. 19-20.  
Baião NC and Lara LJC (2005). Oil and fat in broiler nutrition. Brazilian Journal of Poultry Science 7(3): 129-141. DOI:  
156  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.  
Blair R (2018). Nutrition and feeding of organic poultry, 2nd Edition. Centre for Agriculture and Bioscience International (CABI), England, UK, pp  
Codony R, Guardiola F, Tres A and Barroeta AC (2017). Quality control and nutritional value of fats. In: M. Francesch et al. (Editors), Proceedings  
of the 21st European Symposium on Poultry Nutrition: Plenary session 06. Hot Topics: sustainability on poultry feeding, Salou/Vila-seca,  
Spain, pp. 118123. Google Books  
Dominguez R, Pateiro M, Gagaoua M, Barba FJ, Zhang W and Lorenzo JM (2019). A comprehensive review on lipid oxidation in meat and meat  
products. Antioxidants 8(10): 429. DOI: 10.3390/antiox8100429  
European Food Safety Authority (EFSA) Panel on Biological Hazards (BIOHAZ) (2010). Scientific opinion on fish oil for human consumption. Food  
hygiene, including rancidity. EFSA Journal 8(10): 1874. https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2010.1874  
Food and Agricultural Organization of the United Nations World Health Organization (FAO/WHO) (2001). Codex Alimentarius: Fats, oils and  
related products, volume 8. Joint FAO/WHO, Rome, Italy. http://www.fao.org/3/y2774e/y2774e00.htm#Contents  
Food and Agricultural Organization of the United Nations World Health Organization (FAO/WHO) (2017). Codex Alimentarius Commission.  
Standard  
for  
fish  
oils  
codex  
stan  
329.  
Joint  
FAO/WHO,  
Rome,  
Italy.  
Gibson M and Newsham P (2018). Lipids, oils, fats, and extracts. In: Gibson M and Newsham P (Editors), Food science and the culinary arts,  
chapter 16, pp. 323340. Academic Press, Cambridge, US. https://doi.org/10.1016/B978-0-12-811816-0.00016-6  
Goffman FD and Bergman C (2003). Relationship between hydrolytic rancidity, oil concentration and esterase activity in rice bran. Cereal  
Hofmann AF and Borgstrom B (1962). Physico-chemical state of lipids in intestinal content during their digestion and absorption. Federal  
Lall SP and Dumas A (2005). Nutritional requirements of cultured fish: Formulating nutritionally adequate feeds. In: D. Allen Davis (Editor), Food  
Science, Technology and Nutrition. Feed and Feeding Practices in Aquaculture. Sawton, Cambridge, UK, pp 53-109.  
Niu Z, Shi J, Liu F, Wang X, Gao C and Yao L (2009). Effects of dietary energy and protein on growth performance and carcass quality of broilers  
during starter phase. International Journal of Poultry Science 8(5): 508511. DOI: 10.3923/ijps.2009.508.511  
Pond WG, Church DB, Pond KR, Schoknecht PA (2004). Basic animal nutrition and feeding, 5th Edition. John Wiley & Sons, Inc., New Jersey, USA,  
pp. 4041. Google Books  
Rajan RGR and Krishna AGG (2009). Refining of high free fatty acid rice bran oil and its quality characteristics. Journal of Food Lipids 16(4): 589  
Ravindran V, Tancharoenrat P, Zaefarian F and Ravindran G (2016). Fats in poultry nutrition: Digestive physiology and factors influencing their  
utilisation. Animal Feed Science and Technology 213: 1-21. https://doi.org/10.1016/j.anifeedsci.2016.01.012  
Rodriguez-Sanchez R, Tres A, Sala R, Guardiola F and Barroeta AC (2019). Evolution of lipid classes and fatty acid digestibility along the  
gastrointestinal tract of broiler chickens fed different fat sources at different ages. Poultry Science 98(3): 13411353.  
Rodriguez-Sanchez R, Tres A, Sala R, Garcés-Narro C, Guardiola F, Gasa J and Barroeta AC (2019). Effects of dietary free fatty-acid content and  
saturation degree on lipid-class composition and fatty-acid digestibility along the gastrointestinal tract in broiler starter chickens. Poultry  
Science 98(10): 4929-4941. https://doi.org/10.3382/ps/pez253  
Scanes CG and Christensen KD (2019). Poultry Science, 5th Edition. Waveland Press, Inc., Illinois, USA, pp. 65. Google Books  
Sklan D (1979). Digestion and absorption of lipids in chicks fed triglycerides or free fatty acids: synthesis of monoglycerides in the intestine.  
Poultry Science 58(4): 885889. DOI: 10.3382/ps.0580885  
Tancharoenrat P, Ravindran V, Zaefarian F and Ravindran G (2014). Digestion of fat and fatty acids along the gastrointestinal tract of broiler  
chickens. Poultry Science 93(2): 371 379. https://doi.org/10.3382/ps.2013-03344  
Vallabha VS, Indira TN, Lakshmi AJ, Radha C and Tiku PK (2015). Enzymatic process of rice bran: a stabilized functional food with nutraceuticals  
and nutrients. Journal of Food Science and Technology 52(12): 82528259. DOI: 10.1007/s13197-015-1926-9  
Wiseman J and Blanch A (1994). The effect of free fatty acid content on the apparent metabolizable energy of coconut/palm kernel oil for broiler  
chickens aged 12 and 52 days. Animal Feed Science and Technology 47(3-4): 225236. https://doi.org/10.1016/0377-8401(94)90126-0  
Wiseman J, Powles J and Salvador F (1998). Comparison between pigs and poultry in the prediction of the dietary energy value of fats. Animal  
Feed Science and Technology 71(1-2): 1-9. https://doi.org/10.1016/S0377-8401(97)00142-9  
Wiseman J and Salvador F (1991). The influence of free fatty acid content and degree of saturation on the apparent metabolizable energy value  
of fats fed to broilers. Poultry Science, 70(3): 573582. DOI: 10.3382/ps.0700573  
157  
To cite this paper: Thng A, Ting JX, Tay HR, Soh CY, Ong HC and Tey D (2020). The use of predicted apparent metabolizable energy values to understand the oil and fat  
variability in broilers. Online J. Anim. Feed Res., 10 (4): 150-157.