Catching and crating may elicit stress and fear reactions in poultry because the procedures involve human contact and exposure to a novel environment. This study determined the effects of dietary probiotic supplementation on physiological stress, underlying fear, and growth performance of Pekin ducks subjected to catching and 4 h of crating. The study used a 2 × 2 factorial arrangement; the main factors were diet (basal or basal + probiotic) and crating durations (0 or 4 h). From 1 to 21 days of age (doa), birds were fed a basal or basal + probiotic (CLOSTAT® (Bacillus subtilis) (Kemin Industries, Inc., Des Moines, IA, USA), 1 g/kg) diet. At 21 doa, an equal number of ducklings from each dietary group were caught and crated for 4 h or left undisturbed in the home pens. Birds were examined for serum corticosterone (CORT), heat shock protein (HSP) 70, creatine kinase (CK), triglyceride (TG), glucose (GLU), cholesterol (CHOL), and lactate (LAC) concentrations, heterophil to lymphocyte ratios (HLR), tonic immobility (TI) duration, open-field (OF) test, body weight (BW), and feed conversion ratios (FCR). Diet had no significant (p > 0.05) effect on CORT among the non-crated ducks. However, after catching and crating, birds fed the control diet had significantly (p < 0.05) higher CORT than their probiotic-supplemented counterparts. Catching and crating significantly (p < 0.05) elevated HSP70, HLR, GLU, and CHOL but reduced TG in ducks. Birds fed the probiotic-supplemented diet showed significantly (p < 0.05) lower HSP70, HLR, TG, and CK than those fed the control diet. Probiotic-supplemented ducks showed reduced fear-related behaviours, including TI durations, ambulation latency, and body shaking. Diet had a negligible effect on body weights and FCR of ducks at 21 doa. In brief, catching and crating for 4 h augmented Pekin ducks’ physiological stress and fear reactions, and supplementing birds with probiotics was beneficial in ameliorating these detrimental effects.
Prenatal auditory stimulation was evaluated for its effects on physiological stress indicators (heat shock protein 70 [HSP70], corticosterone [CORT], and ceruloplasmin [CPN]) and behavioral responses in Khaki Campbell ducklings subjected to catching and crating on post-hatch day 7. Fertilised eggs were assigned to three treatments: no additional sound (CONTROL), music (MUSIC; Mozart K.488), or noise (NOISE; vehicle horn), each at 90 dB SPL from embryonic day 15 until hatching. On post-hatch day 7, ducklings were crated for 4 h, after which physiological and behavioral responses were assessed. Catching and crating increased CORT, CPN, and HSP70. Ducklings exposed prenatally to MUSIC or NOISE exhibited lower CORT than CONTROL birds, with CPN concentrations lowest in NOISE. Behavioral responses varied among the PAS × crating treatment combinations, while T-maze success differed overall among the six treatment combinations, although adjusted pairwise comparisons were not significant. Overall, prenatal auditory stimulation modulated physiological responses, while selected behavioral responses varied among PAS × crating treatment combinations, suggesting potential effects on post-hatch stress responsiveness and behaviour.