Effects of semi-open water and non-water enrichment on welfare, production, behavior, and microbial exposure of grow-out Pekin ducks.

Environmental enrichment plays an important role in the welfare, behavior, and health of commercially raised Pekin ducks. We assessed the effects of three enrichment treatments and a control: Nipple line (CON), whiffle ball (EED), preening cup (PC), and Pekino (PEK) on duck welfare, behavior and bacterial exposure. 525 grow-out Pekin ducks were housed in 4 pens/4 rooms with one of the four enrichment types (N = 4 pens/treatment). Body weights and body condition scores of 10 ducks/pen and FCR, ammonia level, and litter moisture % were recorded weekly. On 16 and 44 days of age, 3 ducks/pen were euthanized and their organs were weighed and whole brains collected. Behavior data were collected using scan sampling with video being recorded for 72 continuous hours for 3 weeks after enrichment placement. Weekly samples were also collected for viable bacterial counts, and 16S rRNA gene sequencing at baseline and 6 h after baseliner. Body morphometrics, FCR, ammonia levels, litter moisture % and viable bacteria were analyzed by 2-way ANOVA with repeated measures. Body condition scores were analyzed with PROC LOGISTIC (SAS 9.4). GLIMMIX procedure (SAS 9.4) was used to analyze behavior. Bacterial communities were characterized using 16S rRNA gene sequencing, and functional potential was predicted using PICRUSt2. PEK and PC ducks were largest in weight (p < 0.0001) and better nostril scores (p = 0.0005) but had dirtier feathers (p < 0.0001), worse litter conditions (p < 0.0001) and more viable bacteria in their water sources (p < 0.0001), while the PC and EED ducks had worse feather quality (p = 0.0021). Alpha and beta diversity metrics revealed that microbiota composition was significantly (p < 0.05) dependent on environmental enrichment type. Likewise, functional pathway analyses revealed distinct (p < 0.05) metabolic capacities, including aerobic respiration and amino acid biosynthesis, between microbiotas of each respective environmental enrichment niche. Our study suggests that semi-open water sources and EEDs may lead to an increase in feather pecking and a decrease in feather quality with a low number of ducks per enrichment as well as an increase in bacteria load and litter moisture.