Schothorst Feed Research Institute in the Netherlands has just completed a trial comparing the two main sources of methionine, DL-Methionine (DLM) and DL-Hydroxy-Methionine (HMTBA).

Ross 308 broilers were fed with four diets, formulated around the Aviagen 2010 recommendations: -20 per cent; -10 per cent, adequate and +10 per cent (grower diet) and using DLM or HMTBA.

Birds reached similar good performances for body weight gain and feed conversion ratio, whatever the methionine level used (Table 1).

Table 1. Global effects of methionine sources on broiler performance (days 0-28)
Product	Bodyweight gain g/bird	Feed intake g/bird	Feed conversion
DLM	1,557	2,146	1.378
HMTBA	1,560	2,148	1.377
P	0.809	0.929	0.861

The calculation of methionine efficiency giving the mg of methionine needed to gain one gram of bodyweight showed that HMTBA had a similar efficacy to DL-Met at low methionine levels, but a higher efficacy at high levels in the grower phase and in the overall period (0-28 days) (Figure 1).

Taking DL-Methionine efficacy as the reference, the biological value of HMTBA in the grower phase ranged from 98.6 per cent (-10 per cent methionine than usual) to 102.8 per cent (10 per cent methionine than usual).

This trial provides evidence that both HMTBA and DLM, when supplemented on an equimolar basis and at practical Total Sulphur Amino Acids levels, are equally effective in improving performances of broilers up to 28 days.

It confirms the results of two recent trials achieved in Bangkok Animal Research Center (BARC) in Thailand.

The first one, ran on Ross 308 broilers up to 35 days, proved that both methionine sources could sustain similarly body weight gain, feed intake and feed conversion over the entire period, whatever the amino acid recommendation profile used (Lemme et al. 2010 or Rhodimet Nutrition Guide, 2013).

The second one compared the two methionine sources in diets with different nutrient densities, using the same amino acid/energy ratio. As expected, the nutritional specifications significantly affected broilers performances but no differences were observed between DLM and HMTBA on bird performances, irrespective of the nutrient density.

Together, these three trials, achieved in two independent and renowned research institutes, confirm that when used in practical diets even in different situations, DLM and HMTBA are equivalent methionine sources on a biological point of view. These trials and other scientific results on absorption and conversion answer and close the question which has been debated around the world for nearly three decades.

Adisseo will be at EuroTier 2014 - Hall 16/D12.

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