Dietary supplementation of sodium butyrate for mixed-parity sows during lactation

•Sodium butyrate (SB) dietary supplementation for lactating sows modulated milk fatty acid profile.•SB dietary supplementation for lactating sows did not influence performance and blood parameters of sows of different parity orders.•SB dietary supplementation for lactating sows did not affect piglets performance. The aim of this study was to evaluate dietary supplementation of sodium butyrate for mixed-parity sows during lactation on reproductive performance, milk composition, blood parameters and litter performance. A total of 192 sows were distributed in a completely randomized design in a 4 × 4 factorial arrangement, considering 4 experimental diets (diet without sodium butyrate, diet with 0.1% and 0.2% coated sodium butyrate, and diet with 0.066% uncoated sodium butyrate) and 4 parity order groups (1st, 2nd, 3rd and 4th, 5th to 7th), totaling 16 treatments with 12 replicates each, considering each sow and their litter as experimental unit. Dietary supplementation of sodium butyrate did not influence the reproductive performance of sows and productive performance of piglets during lactation (P > 0.05). There was an effect of parity orders on body weight at farrowing and weaning, average daily feed intake and estimated daily milk production of the sows (P