Two experiments involving 168 10-d-old weaned pigs were conducted to compare growth-promoting properties of dietary spray-dried animal plasma (SDAP), spray-dried porcine plasma (SDPP), and chicken egg-yolk antibodies (EYA) or egg-yolk powder (EYP, contains no specific antibodies) from d 0 to 14 postweaning. In Exp. 1, 96 pigs (3.2 +/- 0.2 kg BW) were used to test the hypothesis that the superior performance of piglets fed SDPP-based diets was partly due to the presence of specific antibodies against enterotoxigenic Escherichia coli (ETEC), which could be replaced with EYA. Four experimental diets in a completely randomized design and arranged in a 2 x 2 factorial (SDPP without or with autoclaving [AuSDPP] and without [EYP] or with supplementation of EYA) were used. Autoclaving SDPP at 121degrees C for 15 min completely destroyed anti-K88/F18 antibodies. Overall feed intake and gain:feed ratio were similar (P > 0.05) among treatments and averaged 122.7 g/d and 0.688, respectively. However, pigs fed AuSDPP+EYP diets had poorer (P < 0.001) ADG compared with those fed SDPP+EYP or SDPP+EYA from 0 to 14 d. Scours were four times higher (P < 0.05) for treatment AuSDPP+EYP compared with all other treatments. Plasma urea nitrogen concentration was higher (P < 0.05) in AuSDPP+EYP- and AuSDPP+EYA-fed pigs. Also twice the number of piglets fed AuSDPP+EYP appeared unhealthy compared with piglets on treatment AuSDPP+EYA. In Exp. 2, 72 10-d-old weaned pigs (3.5 kg BW) were used to compare the effect of EYA supplementation and oral challenge of ETEC strain F18 on performance and visceral organ weights. The experimental diets consisted of SDAP+EYP, SDAP+EYA, SDPP+EYP, and SDPP+EYA. From d 0 to 7, and the entire experimental period, dietary treatment did not influence (P > 0.05) growth rate and feed consumption. Plasma urea N concentration was higher (P < 0.05) in piglets fed the SDAP+EYP diet before and after the oral challenge. Gain:feed ratio, organ weights, villi heights, and crypt depths were not affected (P > 0.05) by dietary treatments. The results indicate that SDPP contains specific anti-ETEC antibodies, which is one of the factors responsible for its superior growth-enhancing effects. Spray-dried animal plasma, SDPP and EYA have similar growth promoting effect in early-weaned pigs.