Effects of Various Feed Additives on Finishing Pig Growth Performance and Carcass Characteristics: A Review

SIMPLE SUMMARY: There are numerous feed additives that can be used to enhance grow–finish pig growth performance and carcass characteristics, which can potentially lead to a higher economic return. Therefore, we collected scientific data to summarize the results of these additives’ effects on grow–finish pigs. The feed additive categories chosen were acidifiers, betaine, chromium, conjugated linoleic acid, copper, direct-fed microbials, carbohydrases, proteases, phytases, multi-enzymes, essential oils, L-carnitine, yeasts, and zinc. We found that most of the results for each feed additive showed positive outcomes. For daily gain, direct-fed microbials, copper, L-carnitine, and multi-enzymes showed relatively large (>2.1% improvement) and positive effects. For feed efficiency, acidifiers, betaine, conjugated linoleic acid, multi-enzymes, direct-fed microbials, L-carnitine, and yeasts showed relatively large (>2.5% improvement) and positive effects. For backfat thickness, except for betaine, chromium, conjugated linoleic acid, and L-carnitine, most feed additives showed little effect (<1.7% improvement). This review provides information on the feed additives that have the most evidence in improving the performance of grow–finish pigs for pork producers around the world. ABSTRACT: Feed additives have shown benefits throughout the literature in improving grow–finish pigs’ growth performance and carcass characteristics. However, the results have not been well summarized. Therefore, this review summarizes the available research (402 articles) on 14 feed additive categories fed to grow–finish pigs. The categories were acidifiers, betaine, Cr, conjugated linoleic acids, Cu, direct-fed microbials, carbohydrases, proteases, phytases, multi-enzymes, essential oils, L-carnitine, yeasts, and Zn. Qualified articles were collected and selected based on inclusion and exclusion criteria from online databases. The percentage difference for each response variable between the treatment and control group was calculated and summarized. Most results were positive for each feed additive; however, the magnitude of improvement varied, and most were not statistically significant. For ADG, DFM, Cu, L-carnitine, and multi-enzymes showed relatively large positive effects (>2.1% improvement) across a reasonable number of articles. Acidifiers, betaine, CLA, multi-enzymes, DFM, L-carnitine, and yeasts showed relatively large positive effects (>2.5% improvement) on improving G:F. Moreover, except for betaine, Cr, CLA, and L-carnitine, most feed additives showed little and non-significant effects on BF thickness (<1.7% improvement). This review provides a descriptive analysis for commonly used feed additives in the hope of better understanding feed additives’ effects on grow–finish pigs.