Effects of autolyzed yeast on performance, blood parameters, intestinal morphometry, immunohistochemistry and microbiological parameters of weaned piglets in a tropical humid climate

Abstract This study aimed to evaluate the effects of dietary supplementation of autolyzed yeast (AY) from fermentation of sugarcane on performance, blood parameters, intestinal morphometry, immunohistochemistry and microbiological parameters of weaned piglets of different weight categories. A total of 480 piglets were distributed in a 3 x 2 factorial design study, with three inclusion levels of AY (0, 4 and 8 g/kg) and two weight categories (light and heavy, 5.71 ± 0.21 kg and 6.99 ± 0.25 kg, respectively), i.e., 6 treatments with 8 replicates pen each. There was no significant interaction between weight category and linear or quadratic effect of AY levels on performance, blood parameters, intestinal morphometry, immunohistochemistry and microbiological parameters (P > 0.05). The dietary supply of AY for nursery piglets linearly decreased the monocytes concentration of the piglets at 63 days of age (P < 0.05). AY levels linearly increased the villus height, mucosal thickness, absorptive area and number of mitotic cells of the duodenum, as well as the villus height:crypt depth ratio, mucosal thickness and number of mitotic cells of the jejunum (P < 0.05). Heavy piglets had higher ADFI in all evaluated periods, as well as higher values of villus height in the duodenum, and mucosal thickness in the duodenum and jejunum than light animals (P < 0.05). Dietary supplementation of autolyzed yeast positively influences health status, intestinal morphometry and immunohistochemistry of nursery piglets. Heavy weaned piglets have higher feed intake and greater intestinal morfometry than light animals.