Metabolizable Energy of Soybean Meal and Canola Meal as Influenced by the Reference Diet Used and Assay Method

Abstract

A 21-day experiment was conducted to study the effect of reference diet type and assay method on apparent metabolizable energy (AME) and nitrogen-corrected (AMEn) of soybean meal (SBM) and canola meal (CM). Broilers (n = 240) were allocated to 10 treatments with eight replicates/treatment and three birds/replicate. Treatments included corn-SBM or corn-CM reference diets (RD). To each RD, 300 or 450 g/kg of SBM or CM were added to make a total of eight test diets. For the difference method, AME of SBM and CM substituted at 300 g/kg in corn-CM RD gave greater AME values compared to inclusion in the corn-SBM RD. The AMEn of SBM increased with increase in inclusion level in the corn-CM RD but AMEn of CM decreased with increased inclusion level of CM in the corn-SBM RD. For the regression method, AME and AMEn of the test feedstuffs were greater with corn-CM RD compared with corn-SBM RD. The AME of SBM was not affected by assay method, whereas AME of CM was lower when determined using the regression method. In conclusion, both the reference diet type and assay method influenced assayed AME and AMEn value of test protein feedstuffs and should be considered in cross-studies comparisons.

Influence of Broiler Age on the Apparent Metabolizable Energy of Cereal Grains Determined Using the Substitution Method

“…However, since the same samples of the four cereals were evaluated in both studies, a general inference of the effect of methodology could be made. Consistent with previously published research, the AME estimates were influenced by the methodology [ 12 , 13 , 37 ]. There were two key differences between the findings of the two studies.…”

“…Lockhart et al [ 12 ] reported that the AME of wheat was lower when measured by the direct method (12.91 vs. 13.09 MJ/kg). Veluri and Olukosi [ 13 ], comparing the substitution and regression methods, found that the assay method can influence the AME and that methodology differences should be considered in comparisons across studies. Lee and Kong [ 37 ] found that the AME of barley measured by the direct method was lower than that measured by the regression method (11.42 vs. 12.43 MJ/kg).…”

“…Estimation of AME of a feed ingredient, therefore, can vary depending on the methodology [ 9 , 12 , 13 ]. In our previous study [ 4 ], the direct method was employed to determine the AME of wheat, sorghum, barley, and corn at different ages (1–6 weeks) of broiler chickens.…”

Apparent metabolizable energy of cereal grains for broiler chickens is influenced by age

“… Olukosi (2021) reported that the AMEn value of barley measured by the regression method was 708 kcal/kg greater than that measured by the substitution method (2,622 vs. 1,914 kcal/kg); however, the AMEn of corn was not influenced by the methodology suggesting that the influence of the methodology on AME estimations is ingredient dependent. Similarly, Lee and Kong (2019) comparing direct vs. regression methods and Veluri and Olukosi (2020) studying substitution vs. regression methods, showed that the assay method can influence the AME and AMEn value of feed ingredients, and that should be considered in cross-study comparisons. Given that the methodology can influence AME estimates, future studies are warranted to measure the AME of cereals using other methods at different broiler ages.…”

Validation of a 3-point model for the determination of energy values using the regression method in broiler chickens

“…The ME results from Exp. 1 fall within these reported ranges, however, some authors report the ME or AMEn to range from 2,000 to 2,486 kcal/kg DM ( NRC, 1994 ; Zhang and Adeola, 2017 ; Veluri and Olukosi, 2020 ). One explanation for these values being greater than what was observed in the current study is the fat content of the CM evaluated.…”