The effect of feed restriction and housing system on performance, organ proportion and microbiota

Abstract

The aim of the present study was to evaluate the effects of feed restriction and the combination of feed restriction with pasture on the performance parameters of fast-growing chickens, the proportion of internal organs and the caecum microbiota. In the experiment, one-day-old Ross 308 chickens were divided into three groups. Group 1 was fed ad libitum (AL), group 2 was restricted on feed at a rate of 70% ad libitum (R), group 3 was restricted to the same age and level as group 2, and was restricted to 22 days on pasture (FR). Feed restriction and the combination of feed restriction and pasture significantly reduced body weight beginning at the age of 14 days and at the end of the experiment (at 35 days), mortality, and the European Production Efficiency Factor (EPEF) but improved the feed conversion ratio (FCR) beginning at the 4 th week of age. Conversely, feed restriction and the combination of feed restriction and pasture significantly increased the proportion of liver, gizzard and Lactobacillus in the caecum. In summary, feed restriction and the combination of feed restriction in the free range had negative effects on growth, feed conversion ratio and economic profit, presumably because of the short realimentation period and because pasture did not have a beneficial effect.