Late-Breaking: Effects of farm noise on ileum intestinal barrier function of pullets.

Noise is a potential but not negligible environmental factor in animal husbandry. To investigate the effects of farm noise on intestinal barrier function of pullets, 336 Hailanhe pullets aged 1 day were randomly divided into 3 groups: control group (CON), low noise group (LN), high noise group (HN). LN group and HN group were exposed to noise respectively at 65-75 dB and 85-95 dB, the average and the range of the highest loudness of noise in laying hens' farms for 6h every day (7:00-19:00, hourly intervals for one hour) and lasted 4 weeks. Non additional noise addition in CON group, noise loudness of which was less than 40dB. 6 birds were randomly chosen form each group after every week of noise stimulation for ileum tissue samples. Hematoxylin-eosin stain (HE stain), immunofluorescence, and real-time quantitative PCR (qRT-PCR) were used to determine changes in ileum structure, expression of intestinal barrier related proteins and mRNAs and HSPs. Results shown that 1 week and 2 weeks after noise exposed inflammatory cell infiltration reduced, the expression of intestinal barrier related proteins (Occludin, Mucin2 and ZO-1) and mRNAs (Claudin-1, Claudin-4, E-cadherin, Occludin, Mucin2, ZO-1 and ZO-2) were significantly increased (P < 0.05), the mRNA expression of HSPs decreased (P < 0.05) or have no significate changes (P > 0.05). After 4 weeks of noise treatment, the expression of mRNAs of intestinal tight junction protein and mucin, HSPs were significantly decreased (P < 0.05). There was no difference between the LN and HN groups on those indicators (P > 0.05). The study indicates that noise at 65-75dB and 85-95dB does not cause stress to ileum of pullets while promote the development of intestinal barrier of chicks within 2 weeks maybe by mild stimulation and birds restored to balance due to habitualization after 4 weeks of noise treatment. [ABSTRACT FROM AUTHOR]