Effects of dietary inclusion of direct-fed microbials on growth performance and carcass traits of finishing pigs

Abstract Text:

This study was to determine the effect of direct-fed microbials (DFM, PrimaLac, Star Labs, Clarksdale, MO) on the growth performance and carcass traits of finishing pigs. PrimaLac includes Lactobacillus acidophilus (2.5 x 10⁷ cfu/g), Lactobacillus casei (2.5 x 10⁷ cfu/g), Bifidobacterium thermophilum (2.5 x 10⁷ cfu/g), and Enterococcus faecium (2.5 x 10⁷ cfu/g). Sixty pigs at 88.5 ± 0.6 kg BW were housed in pens (3 pigs/pen) and allotted to 2 dietary treatments (0 or 0.05% DFM) in a randomized complete block design with sex and initial BW as blocks. There were 5 gilt pens and 5 barrow pens per treatment. Pigs were fed experimental diets which had corn, DDGS, and soybean meal as major ingredients meeting the NRC nutrient requirements (2 phases and 2 wk each). Body weight and feed intake were measured weekly. At the end of the study, pigs were moved to a local packing plant to process the carcass. Cold carcass (24 hr after processing) was used to measure backfat thickness at 1^st, 10^th, and last ribs. Loin was removed, weighed, and the middle part was removed for the determination of loin color (Minolta colorimeter), marbling score (1 to 5, NPPC scale), drip loss (48 hr), and chemical composition. Data were analyzed using Proc Mixed of SAS with treatment and sex as fixed effect and initial body weight blocks as a random effect. Pigs with DFM had greater (P < 0.05) ADFI (2.79 and 2.56 kg/d) and ADG (0.89 and 0.79 kg/d) than pigs without DFM during 4 wk feeding period. Loin tended to be heavier (P = 0.100) for pigs with DFM (7.55 kg/side) than pigs without DFM (6.64 kg/side). There was no difference in backfat thickness between treatments. Chemical composition (dry matter, crude protein, ether extract, and crude ash) and drip loss did not differ between treatments. Loin samples from DFM treatment tended to be lighter (P = 0.054, 53.9 vs. 51.9 L* value). Collectively, growth performance of pigs was enhanced by dietary supplementation of DFM without affecting loin quality.

Keywords: Direct fed microbials, Finisher pigs, Growth performance, Loin