Sequential feeding with low- and high-lysine diets increases activity and improves gait score in broiler chickens

Preventing leg disorders in broilers, without changing their body weight at slaughter age and their rearing time is a challenge for poultry production. The method of prevention we studied consisted in alternating the distribution of different diets. This kind of diet schedule is called “sequential feeding”. The alternation of poorand rich-lysine diets was used in order to reduce early growth and to enhance locomotor activity, two factors that reduce leg disorders. The aim of this work was to study the effects of various sequential feeding on growth, feed intake, feed conversion, activity, leg disorders and bone quality of broilers. The experiment was carried out on 330 meat-type chickens (Ross) reared in 30 pens of 2.89 m 2 (11 male chickens / pen; 10 pens / group) and slaughtered at 42 days. From Day 10 to Day 22, control birds were fed every day with a standard diet (Feed 100 = 100% of standard lysine level), whereas 24Hand 48H-cycles were used for sequential feeding in the C24 and C48 group respectively. Broilers of the C24 group were fed a poor lysine diet (F70) during half of the light phase and with a rich lysine diet (F130) during the other half (Feed 70 = 70% of standard level of lysine and Feed 130 = 130% of standard level of lysine). Feeds 130, 100 and 70 had equal energy and protein content (ME = 3,230kcal/kg; CP = 23.2%). Broilers of the C48 group were fed Feed 70 for one day and Feed 130 every other day. We measured body weight of birds, feed intake, feed conversion, motor activity, gait score and bone quality at slaughter age. Body weight at Day 22 was significantly lower in the C24 and C48 groups than in the control group, but body weights and feed conversion ratios were significantly equivalent to controls at slaughter. Broilers of C24 and C48 groups spent significantly more time standing than the control birds (47% and 49% vs. 40%) but their bone quality was not improved. The occurrence of birds with abnormal gait was significantly reduced in C24 and C48 groups (33% and 36%) compared to control (55%). Both schedules of sequential feeding were effective in improving gait score. The reduction of leg disorders noticed in the C24 and C48 groups was not explained by changes in bone composition but by reduction of early growth of birds and by enhancement of their activity level. ___________________________________________________________________________ Key-words: welfare; chicken; leg problems; nutrition; lysine.