NUTRITION ▶▶▶ Figure 1 - Feed intake, Body weight gain and FCR at 42 days.
7,000 6,000 5,000 4,000 3,000 2,000 1,000 0,000
Feed intake (kg) Body weight gain (kg) FCR
2,000 1,990 1,980 1,970 1,960 1,950 1,940 1,930 1,920 1,910 1,900 1,890
1 - Basal diet
2 - DLM 3 - DLM 4 - DLM
Carcass and breast weights increased with methionine addi- tion, the effect similar between sources (Figure 2). Carcass yield and breast yield (expressed relative to body weight) were not affected by treatments. However, a linear regression mod- el performed on the breast meat yield indicated that it in- creased linearly with methionine addition (P = 0.001). Feather weight is particularly important in duck production not only for their support of performance and health, but also as a valuable co-product. At 42 days of age feather weight was significantly lower for birds fed the basal diet, compared to those supplemented with either source of methionine. No sig- nificant difference of feather weight or yield was observed be- tween OH-Met and DL-Met, suggesting they promote feather growth in the same way.
Bio-efficacy of methionine sources Methionine efficacy was calculated as the extra methionine in- take per extra weight gain – results were similar between sources. To determine the actual bio-efficacy of OH-Met rela- tive to DL- Met, researchers used an exponential model of the growth rate as a function of the TSAA intake, taking into con- sideration the differences in feed intake. Body weight gain for the two sources followed the same exponential response, with no significant differences. Bio-efficacy was calculated as a steepness coefficient ratio of 99% with a confidence interval ranging from 86% to 112%. This modelling confirmed that OH-Met and DL-Met have the same bio-efficacy to promote duck performance.
Antioxidant capacity of meat Concentrations or activities of some redox markers in breast muscle were improved by addition of OH-Met, compared to DL-Met, including total antioxidant capacity of meat, glu- tathione peroxidase (GPX) activity and concentration of re- duced glutathione (GSH) in the breast muscle. Because of the improvement of the antioxidant capacity observed with
5 - DLM
6 - OH- Met
7 - OH- Met
8 - OH- Met
9 - OH- Met
OH-Met, it is a better candidate than DL-Met to reduce oxida- tive processes in the meat during post-mortem storage and may result in better duck meat quality.
Implications for profitability Nutritional expertise, as well as scientific and technical knowl- edge, should be used to achieve cost-effective feed formula- tions for ducks. Underestimating the importance of methio- nine in poultry nutrition can have a huge economic impact. The study, published 2018 in Poultry Science, concluded that OH-Met is 100% efficient to sustain growth performance and feather development of Cherry Valley ducks, the latter being an important economic parameter of duck production. More- over, OH-Met confers extra benefits in terms of profitability of duck production. It improved antioxidant capacity of muscle, which would reduce oxidation in meat during storage contributing to better duck meat quality.
References available upon request.
Figure 2 - Breast weight at 42 days. 350
300 250 200 150
100 50 0
1 - Basal diet
2 - DLM 3 - DLM 4 - DLM 5 - DLM 6 - OH- Met
7 - OH- Met
▶ POULTRY WORLD | No. 1, 2019
8 - OH- Met
9 - OH- Met
27 b ab a b b ab b b b
Breast weigth (g)
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