Effect of precision air supply cooling system with different cooling air speed on reproductive performance, stress status, immunoglobulin and fecal microbiota of lactating sows

This study investigated the precision air supply cooling system with different cooling air speed on reproductive performance, stress status, immunity and intestinal microbiota of sows. A total of 36 sows were randomly assigned into three groups: control group (CON, n = 12) without cooling system, low cooling air speed (2.24 ± 0.11 m/s) group (LCAS, n = 12) with precision air supply cooling system, high cooling air speed (3.33 ± 0.11 m/s) group (HCAS, n = 12) with precision air supply cooling system. The average daily ambient temperature and relative humidity in experimental farrowing rooms were 28 °C–32 °C and 65%–90%, respectively, during daytime (8:00–20:00). The reproductive performance, respiratory rate (RR), body surface temperature (BST), rectal temperature (RT) salivary parameters and fecal microbiota of lactating sows were measured. The results showed that compared with CON group, average daily feed intake of sows and average daily gain of piglets were increased (P < 0.05) in LCAS and HCAS groups. The RR, BST and RT were decreased (P < 0.05) in LCAS and HCAS groups in wk 1 before parturition and wk 2 after parturition. The salivary cortisol and alpha amylase level of LCAS and HCAS sows were decreased (P < 0.05) on d 14 after parturition, while the salivary immunoglobulin A and immunoglobulin G level of LCAS and HCAS sows were increased (P < 0.05) on d 7 after parturition. The LCAS and HCAS sows showed higher relative abundance of Clostridium_sensu_stricto_1 in feces, which was positively associated with immunoglobulin A (P < 0.01). In conclusion, both low and high cooling air speed improved reproductive performance, alleviated stress status, and enhanced salivary immunoglobulins and beneficial fecal microbiota community in lactating sows, which indicated that precision air supply cooling system could be an effective cooling strategy for lactating sows in high ambient temperature.