August 8, 2007

Dutch researchers study methionine effects in broilers fed organic diets

Dutch researchers from Wageningen University's Animal Sciences Group have conducted an experiment to study the effects of dietary crude fibre (CF) and methionine on performance and slaughter quality of broilers fed organic diets.

More organically produced raw materials in organic diets appear to raise CF levels and reduce methionine concentration. Through the experiment, the researchers sought to develop 100 percent organic diets that do not negatively impact broiler performance and welfare.

1,680 slow growing broilers (1 to 70 days of age) were studied, with results indicating that an increase in CF content will reduce growth rate and feed intake of the birds.

However, the effect of CF content on feed conversion ratio depends on the age of the bird, according to the researchers.

While higher CF content was found to reduce feed conversion ratio during the first 50 days of the growth period, it improved feed conversion ratio over the last 20 days. Looking at the growth period as a whole, CF content was not considered to affect feed conversion ratio.

On the other hand, reduced methionine concentration in the diet led to lower final weight of the broilers.

The researchers also concluded that bird strain, rather than CF content and methionine concentrations, affected slaughter quality. As almost all slaughter quality parameters were found reduced in Master Gris compared with JA957 broilers, Master Gris birds were not recommended for raising as organic broilers.