Yeast extract could be used as a partial substitute for spray-dried porcine plasma in diets for weaned pigs

Abstract The previous study has been identified that yeast extract (YE) could be a potential substitute for spray-dried porcine plasma (SDPP) as a superior protein ingredient in diets for pigs in terms of the available energy and AA digestibility. This experiment was conducted to test the hypothesis that YE as a partial substitute for SDPP in diet could stimulate the immune responses and improve the performance and nutrient digestibility in weaned pigs. A total of 90 healthy pigs weaned at 28 d of age (8.5 ± 1.2 kg) were assigned into 3 treatments according to sex and weight in a randomized complete block design. The dietary treatments consisted of a negative control diet without YE and SDPP supplementation (NCD), NCD supplemented with 40 g/kg SDPP at the expense of soybean meal (SDPPD) or SDPPD supplemented with 20 g/kg YE at the expense of SDPP (YED). During the 28-d experimental periods, pigs fed YED and SDPPD improved average daily gain ( P P P P P  = 0.09) urea nitrogen and diamine oxidase contents in serum. The serum IgG and IgM content was greater in pigs fed SDPPD and YED than those fed NCD ( P P P P