Comparison of gizzard activity between chickens from genetic D+ and D-lines selected for divergent digestion efficiency

Abstract

Gizzard motility was compared between chickens from D+ (high digestion efficiency) and D- (low digestion efficiency) genetic lines selected for divergent digestion efficiency, using strain gauge transducers. Motility was recorded continuously during 24 h in 6 birds per line. Two stimuli, a meal distribution after a feed-deprivation period and lighting after a dark period, were tested during the recording period. A functional test with intravenous injection of serotonin performed at the end of the recording day often resulted in a sharp reduction in gizzard motility, without a significant difference between lines. Compared with D+ birds, gizzard activity in D- birds remained high during fasting or dark periods (P < 0.0006), which reduced the effects of stimuli in D- birds. So, coordination between bird activity and gizzard motility tended to be reduced in D- compared with D+ birds (P = 0.0018). This coordination was observed to be positively correlated (P = 0.011) with the relative weight (g/kg of BW) of the stomach (gizzard + proventriculus). This experiment pointed out differences in gizzard motility between D+ and D- chicken lines in terms of response to environmental stimuli, characterized by a failure in the gizzard relaxation process in D- birds during rest periods. © 2012 Poultry Science Association Inc.