Inclusion of Palm Kernel Meal with β-mannanase on Growth Performance, Immune Responses, Fecal Mannan Content and Microbial Flora in Weaning Pigs

Abstract

There are serious concerns about the additional opening of domestic agriculture and livestock market by FTA between Korea and other countries such as EU, USA or China. The Korean feed industry is trying to search for cheaper alternative feed ingredients to reduce cost of feed production. Among those ingredients, palm kernel meal (PKM) has paid attention due to affordable price and higher nutrients. However, PKM contains high levels of mannan which cannot be digested in GI tract of mono-gastric animal thus it is regarded as an anti-nutritional factor. Therefore, the exogenous β-mannanase is considered to include with PKM in the diet for weaning pigs in order to degrade natural anti-nutritional factor (mannan) into mannan-oligosaccharides (MOS) which functions as a prebiotic source. The current experiment was conducted to evaluate the effect of inclusion of PKM with β-mannanase on growth performance, immune responses, fecal mannan content and microbial flora in weaning pigs. A total of 160 crossbred ([Yorkshire × Landrace] × Duroc) weaning pigs with an average initial body weight (BW) of 6.78 ± 0.31 kg were randomly allotted into one of four dietary treatments based on sex and initial BW according to a randomized complete block design in 5 replicates with 8 pigs per pen. The treatments were 1) CON: basal diet, 2) PKM 0: basal diet + palm kernel meal 5% without β-mannanase, 3) PKM 0.05: basal diet + palm kernel meal 5% + β-mannanase 0.05%, and 4) PKM 0.1: basal diet + palm kernel meal 5% + β-mannanase 0.1%). Two phase feeding program was used in this experiment. The phase I diet was provided for 2 weeks and the phase II diet was given for last 3 weeks. The experimental diets were calculated to meet or exceed the recommendation of NRC (1998). In phase I, the results revealed that pigs fed CON or PKM 0.05 was tended to increase BW than other treatments (P=0.06) whereas a significant improvement in average daily gain (ADG) was also observed (P=0.05). However in phase II, there were no difference in ADG, ADFI and G:F ratio among dietary treatments regardless of PKM or β-mannanase supplementation in phase II. Immunoglobulin G concentration was significantly increased when pigs were fed CON or PKM 0.05 during phase I (P<0.05), whereas there was no significant difference in immunoglobulin A concentration during whole experimental period. The mannan content in feces tended to linearly decrease as β-mannanase was supplemented (P=0.08). There were no significant difference in fecal Escherichia coli and Salmonella spp. counts by dietary treatments during the entire experimental period. Consequently these results demonstrated that supplementation of PKM with or without β-mannanase in weaning pigs diet did not show any positive response due to the fact that growth performance was reduced clearly in phase I although it was recovered in phase II.