The inclusion of a Bacillus-based probiotic in feed to increase the dietary energy available to growing pigs

Abstract

The livestock industry has come under increasing scrutiny for using antibiotics sub-therapeutically as growth promoters. Increased awareness of the negative effects of microbial antibiotic resistance has amplified consumer pressure to raise livestock without the use of these growth promoters. Feed additives and more specifically probiotics could act as an alternative to sub therapeutic AGP use. The aim of this study was to evaluate the effects of a spore-forming probiotic (Bioplus YC, Chr. Hansen Denmark) on the nutrient availability of pig feeds and whether the specific probiotic is able to release additional energy (0.3 MJ/kg or 72 kcal/kg on net energy level) from the undigested or unabsorbed dietary fibre fraction. To achieve the aim, the performance of pigs receiving standard and reduced energy diets, with and without a commercially available probiotic feed additive, was measured. A completely randomised block design experiment was conducted at the University of Pretoria’s experimental farm. One hundred and seventy four male pigs from the PIC 337 line (Pig Improvement Company, USA) with an average body weight of 6.81 kg ± 0.587 kg, were obtained from a local commercial farm. The piglets were randomly selected on weaning day from that week’s weaned piglet batch on 21-days of age. Pigs were randomly allotted to 1 of 4 treatments in a 2x2 factorial arrangement of treatments. Five feeding phases were used to feed 168 male pigs over an 18-week (126 days) trial period. Four treatments were fed during each phase which included two standard energy diets (Treatment 1 and 2) and two reduced energy diets (Treatment 3 and 4). The lower energy diets (Treatment 3 and Treatment 4) were reduced by 0.3 MJ/kg or 72 kcal/kg on net energy level (NE). Treatment 1 and 3 was supplemented with the probiotic at a manufacturer’s standard dosage of 400 mg/kg of final feed. Production parameters (body weight, average daily gain, feed intake, feed conversion ratio and faecal scoring) were measured weekly and per dietary phase. Slaughter parameters (carcass weight, backfat thickness and lean meat percentage) were measured during the slaughter of the pigs at day 148 of age. Supplementing commercial pig diets with a dual strain probiotic significantly improved body weight and body weight gain from the grower 1 phase onwards until slaughter without affecting the feed intake of animals. The addition of a probiotic could influence the cumulated FCR of supplemented pigs in reduced energy diets when compared to standard energy diets. Positive effects were noted in the carcass weight of probiotic supplemented vs. non supplemented animals. Probiotic supplemention of a reduced energy diet resulted in significantly larger carcasses when compared to the unsupplemented reduced energy group. The compounding effects of a beneficial microbiota balance from weaning, together with the various modes of action that the probiotic enables on the GIT over the entire growing period, most possibly contributed to the positive results seen on production parameters.The probiotic used in this study showed potential as a viable alternative to increase growth rate and can form part of nutrition strategies to increase overall gut health and pig performance.