Meta-analysis: Efficacy and efficiency of 3 sources of methionine fed to post-weaning piglets



A meta-analysis made as collaboration between University of California Davis (USA), Sherbrooke R&D Centre Sherbrooke-Quebec (Canada) and Adisseo, in 2023


To evaluate the efficacy and efficiency of 3 methionine (Met) sources to sustain post-weaned piglets growth through the comparison respectively of the protein deposition (g/d) and the Met utilization efficiency (%)


Various studies evaluated the effect of different sources of methionine, DL-Methionine (DL-Met), L-Methionine (L-Met) and OH-Methionine (OH-Met) on swine, sometimes with conflicting results. On the contrary of what is available for poultry, very few meta-analysis were performed in swine to summarize the results of these individual scientific publications. For this reason, a group of scientists decided to update their previous study (Remus et al., 2015), by adding newly published articles and/or optimizing the selection criteria.

From a starting of 2.191 scientific papers testing the dose response of different Met sources, after excluding duplicate studies and the ones not matching the selection criteria, we ended over with 24 papers including 208 treatments from 38 trials run between 1992 and 2018.

The ingredients composition of each diet was used to recalculate nutritional parameters, in particular the standardized ileal digestible (SID) AA, using the EvaPig® software. At the same time, the SID Met requirement was determined using initial and final Body Weight and in accordance to NRC (2012). Data from piglets fed above the SID Met requirements were excluded from database before statistical analysis.

Protein deposition (PD) was calculated assuming 16% retention in Average Daily Gain (ADG) while Met retention was calculated as 2% of PD. Met utilization efficiency was calculated as ration between Met intake corrected by maintenance and Met retained in PD.

A mixed multiple regression model was used to compare the effect of different Met sources.


Met efficacy and efficiency of different sources of Met sources fed at or below SID Met requirements of post-weaning piglets:


Control DL-Met L-Met OH-Met P-Value
Number of observations 36 74 14 21
Body weight average, kg 11.9 ± 0.61 12.0 ± 0.61 12.0 ± 0.62 12.0 ± 0.62 0.67
SID Met intake, g/d 1.6 ± 0.14a 2.0 ± 0.14b 2.0 ± 0.17b 2.0 ± 0.15b < 0.001
Protein deposition, g/d 55.5 ± 3.9a 62.1 ± 3.8b 62.2 ± 4.2b 61.8 ± 4.0b < 0.001
Met utilization efficiency, % 77.1 ± 2.6 74.9 ± 2.5 74.8 ± 3.1 74.0 ± 2.8 0.33


No significant differences between the methionine sources were determined.


A meta-analysis approach including the most recent studies, confirms the absence of significant difference in ADG (expressed as PD) and Met utilization efficiency in response to DL-Met, L-Met and OH-Met fed at or below the requirement.


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