The effect of dietary N,N-dimethyl glycine (DMG) on technical performance, plasma metabolites and broiler ascites syndrome: a challenge study

Introduction DMG is reputed to enhance oxygen supply at cellular level. The primary condition of ascites, being hypoxemia, constitutes a possible application of DMG as a feed additive in broiler rations in order to abate losses due to broiler ascites syndrome and to improve technical performance. The current study intended to investigate these potential benefits of dietary DMG. Materials In total sixty four 14-day-old broiler hens (Ross-308) were reared in 16 pens of 4 birds each until 40 days of age. The birds were challenged with a low environmental temperature (15 °C) and a diet enriched with poly unsaturated fatty acids in form of corn oil in order to provoke ascites. To each pen, one of two test diets was randomly assigned for the whole trial period: a control diet or the same diet addedwith 167 ppm DMG. Mortality, feed conversion ratio (FCR) and apparent metabolizability were recorded at pen level. Further, individual blood samples were taken at the end of the trial, on which hematocrit level (HCT), thiobarbituric acid reactive substances (TBARS) and selected plasma metabolites were analysed. Next, all birds were euthanized and manually dissected, which included assessment of ascites heart index (AHI), carcass and meat%. Results Mortality, clinical ascites and overall FCR were numerically lower in the DMG supplemented groups compared to the controls. Moreover, FCR between 30d and 40d improved with a statistical trend (control:2.33; DMG:2.17; 0.1<P-value<0.05). Next, in contrast to similar HCT, AHI was significantly lower in the treatment groups (-18%, P<0.5). Whereas, meat and carcass% were similar between both feeding groups. Further, apparent dry matter metabolizability was significantly higher when fed the DMG supplemented diet (+3.7%, P