By Anna Naim
Synbiotics (pre- and probiotics) can act as antibiotic alternatives to improve poultry health and behaviour, especially during stress. Synbiotics can be administered in drinking water, however, it is uncertain whether birds can differentiate between synbiotic-enriched water (SW) and pure water (W). Choice experiments were employed to understand changes in animals’ physiology, behaviour, and preference. We investigated whether laying hens preferred SW, and whether synbiotic consumption correlated to feather-pecking behaviour (FP) and feather cover damage (FD). White Leghorns (N=226, 37 WOA) were housed in 12 enriched floor pens. Two colour-coded jugs were presented simultaneously, one providing SW (80mg synbiotic/L W; probiotics including Lactobacillus, Bifidobacterium; prebiotic fructooligosaccharides), the other providing W. Hens were habituated to both water-types for two weeks. Baseline liquid consumption (pre-stress) was recorded for one week. Hens were exposed to chronic, unpredictable social stress for three weeks, followed by a two-week post-stress period. FP was captured via video recordings; FP and FD were evaluated by assessors not informed about treatments. A generalized linear mixed model assessed changes in liquid consumption with fixed effects of water-type, period (pre-stress/stress/post-stress), and their interaction. Hens consumed significantly more SW (78.5ml/bird/day) than W (68.4ml/bird/day) across all periods (F1,703=37.39, p<0.0001), and during each period (pre-stress: t703=4.26, p=0.0003, stress: t703=3.20, p=0.0179, post-stress: t703=3.07, p=0.0266). Generalized linear mixed models assessed odds of lower FD. Hens had better feather cover in pre-stress (OR=2.0, 95%CI: 1.39-2.79) and stress (OR=1.8, 95%CI: 1.25-2.50) than post-stress. No significant difference occurred in FD between pre-stress and stress (OR=1.11, 95%CI: 0.79-1.57). No increase in FP (0.87+/-0.60pecks/bird/10 minutes) existed even during stress (F2,250=0.47, p=0.6240). Hens discerned between water-type with relative preference for SW. FP did not increase during stress, however, FD increased with age due to continued pecking. Given hens’ preference for synbiotics, future research should explore additional health benefits of synbiotics in poultry welfare.
