Impact of a Direct-Fed Microbial at Three Inclusion Rates on Growth Performance in Growing and Finishing Pigs

The increasing restriction of antibiotic use in the swine industry has driven interest in antibiotic alternatives, including direct fed microbials (DFM). The objective of this experiment was to evaluate the growth response to the addition of a direct-fed microbial (LactoPlan, KayDee Feed Co., Sioux City, IA) in the diet of grow-finish pigs. A total of 300 crossbred pigs with an average initial BW of 29.7 ± 0.3 kg were randomly assigned to 60 pens which in turn were randomly assigned to one of 4 dietary treatments according to the completely randomized design. Dietary treatments were 1) negative control, 2) NC plus 0.05% DFM, 3) NC plus 0.10% DFM, and 4) NC plus 0.20% DFM. The experiment was conducted using 4 dietary phases. Pigs were given ad libitum access to water and feed throughout the experiment and were marketed at a constant BW of approximately 125 kg. Data were analyzed using PROC MIXED of SAS (9.4), with initial BW as a covariate. Treatment means were separated using contrasts. There was a trend for 0.05% DFM to increase ADG and ADFI compared to NC. The greatest response was achieved with 0.05% DFM; none of the other DFM levels achieved improvement in ADG or ADFI compared with the control diet. There was no treatment effect for G:F (P≥ 0.10). In conclusion, diets containing 0.05% DFM tended to improve ADG and ADFI over the NC; higher levels of DFM inclusion failed to provide benefit compared with the NC.

Effects of a direct fed microbial on pig growth performance and feed efficiency

Item	NC	DFM			SEM	P-value
		0.05%	0.10%	0.20%		NC vs. DFM	NC vs. 0.05% DFM	NC vs 0.10% DFM		NC vs 0.20% DFM
Initial BW (kg)	29.5	29.5	29.5	29.5	0.25	-	-	-		-
Final BW (kg)	123.7	125.5	125.8	124.7	0.49	0.173	0.180	0.113		0.679
ADG, kg/d	0.848	0.892	0.881	0.847	0.016	0.174	0.060	0.149	0.994
ADFI, kg/d	2.437	2.585	2.542	2.466	0.054	0.138	0.057	0.176	0.708
G:F	0.348	0.346	0.336	0.346	0.008	0.582	0.859	0.283	0.923