Improving weaner pig performance through the inclusion of activated medium chain fatty acids

Alternatives to using antimicrobial compounds in pig production include the use of medium chain fatty acids (MCFA) with a total chain length of 6 to 12 carbon atoms (caproic, caprylic, capric and lauric acid). The MCFA have shown positive effects on intestinal morphology and modification of the gastrointestinal tract microbiota (Dierick et al. 2002). Aromabiotic^® Pig (Nuscience, Drongen, Belgium) is a proprietary blend of high purity activated MCFA that have been designed for use in pigs. The functional effects of MCFA lead to the hypothesis that the inclusion of Aromabiotic^® Pig, with or without the presence of medication, will enhance the performance of weaner pigs.

Newly-weaned pigs aged 23 days and weighing 5.1 ± 0.10 kg (mean ± SE) were housed in pens of 14 and allocated to one of three treatments (n=10) over a 4-week period using a randomised block design with sex, weight and entry time as blocking factors. Pens were weighed weekly, for 4 weeks, with feed disappearance recorded to correspond with weighing events. Pigs had access to feed on an ad libitum basis from a three-space stainless steel feeder, and ad libitum access to water via nipple drinkers. Wheat-based diets were formulated to contain 15.1 MJ digestible energy (DE)/kg and 0.85 g standardised ileal digestible lysine/MJ DE. Protein and amino acid sources in the diets included soybean meal and soy protein isolates, blood meal, meat and bone meal, fish meal and milk powder. The control diet contained 2.5% spray-dried porcine plasma (SDPP). Treatments 1 (T1) and 2 (T2) contained 2.5% SDPP and 0.2% Aromabiotic^® Pig. All diets contained 0.3% fumaric acid. All pigs received 0.25 mL intramuscularly of Draxxin (Tulathromycin 100 mg/mL, Zoetis, NSW) upon entry. Control and T1 pigs also received 65.7 g/1000 kg liveweight (LW) of Sol-u-Mox (Amoxycillin trihydrate 870 mg/g; Bayer, NSW) and 42.9 g/1000 kg LW of Linco-Spectin (Lincomycin hydrochloride 222 mg/g, Spectinomycin sulphate 445 mg/g; Zoetis, NSW) in water for 28 and 21 days, respectively, while T2 was unmedicated. An unmedicated control diet would likely have resulted in active disease becoming a welfare issue, so was not included in this study. Performance data were analysed via GLM ANOVA with time as a blocking factor, with differences determined by least significant difference (P < 0.05). Differences in mortality between treatments were analysed by Chi-square analysis (Genstat, 16th Edition; UK).

Sex effects were not significant. Pigs receiving Aromabiotic^® Pig in the presence of medication grew faster (P < 0.05) than other treatments across the whole experimental period (Table 1), which resulted in heavier pigs at the end of the 4-week period (P < 0.001). Including Aromabiotic^® Pig in diets improved FCR (P < 0.001) and reduced mortality (P < 0.001) compared to the control, whilst removing medication was associated with reduced ADFI (P = 0.003). In the first week after weaning, Aromabiotic^® Pig in the presence of medication improved ADG (P = 0.008), primarily a result of improved FCR (P = 0.002). The poorer growth response in the unmedicated treatment was associated with a reduced intake. However, mortality data suggested that the protective effects of MCFA were still observed. Given this experiment, Aromabiotic^® Pig was found to have a significant positive impact on the performance of weaner pigs.

Table 1.  Performance of weaned pigs receiving 0.2% Aromabiotic^® Pig in the presence (T1) or absence (T2) of medication compared with a medicated Control diet