Effect of dietary inclusion of benzoic acid (VevoVitall®) on the microbial quality of liquid feed and the growth and carcass quality of grow-finisher pigs

Abstract

Benzoic acid has long been used as a food preservative due to its antibacterial and antifungal effects. Supplementation to pig diets has also been shown to inhibit microbial free amino acid degradation and to control yeast growth in fermented liquid feed. However, the effect of dietary inclusion of benzoic acid (BA) in fresh liquid feed for grow-finisher pigs on feed quality and the resultant effects on pig growth remain unclear. The objective of the current study was to compare four inclusion levels of BA (VevoVitall®) on feed microbial quality and on the growth performance of grow-finisher pigs. Two-hundred and sixteen pigs with a starting weight of 30.0kg (± 7.43 SD) were used in the experiment. The four dietary treatments were as follows: (1) Basal diet + 0kg/t BA (0kg/t BA), (2) Basal diet + 2.5kg/t BA (2.5kg/t BA), (3) Basal diet + 5kg/t BA (5kg/t BA), (4) Basal diet + 10kg/t BA (10kg/t BA). Lactic acid bacteria (LAB) counts in the mixing tank were similar across treatments (P>0.05) but were lower in the troughs for the feed supplemented with 10kg/t BA than for all other treatments (P<0.01). The pH of the 10kg/t BA treatment was also lower than that of the other three treatments. However, this only occurred in the mixing tank (P<0.01), as in the trough, the basal diet had the lowest pH (lower than the other three treatments; P<0.01). Dietary BA inclusion did not affect average daily gain, average daily feed intake, feed conversion efficiency, final live-weight, carcass weight or carcass quality during the experimental period (P>0.05). In conclusion, while BA may limit the growth of LAB in liquid feed and stabilise feed pH, its inclusion in the diet did not improve the growth performance or carcass quality of grow-finisher pigs.