# Feeding a Bitter Mix of Gentian and Grape Seed Extracts with Caffeine Reduces Appetite and Body Fat Deposition and Improves Meat Colour in Pigs

## TL;DR

Adding bitter plant extracts and caffeine to pig feed reduces body fat and improves meat color, offering a potential alternative to pure caffeine.

## Contribution

Demonstrates that combining gentian and grape seed extracts with low-dose caffeine can effectively reduce fat and enhance pork color.

## Key findings

- Combining plant bitter extracts with low-dose caffeine reduced feed intake and carcass fat in pigs.
- BM increased meat redness and yellowness while decreasing growth performance and carcass weight.
- Twenty-two proteins related to energy metabolism and muscle structure were upregulated in BM-fed pigs.

## Abstract

Excessive fat content in pork negatively impacts consumer choice. Bitter compounds, such as caffeine, can be used to prevent excessive fat deposition in pigs. However, the use of caffeine as a feed additive has restrictions in several countries. Plant bitter extracts, such as grape seed and gentian, have the potential to be used as a replacement for caffeine due to their capacity to reduce fat tissue development and appetite. The aim of this study was to assess the effects of a gentian and grape seed extract mixture, alone or in combination with caffeine (BM), at increasing doses on the growth performance, carcass traits, and meat quality of pigs. The results showed that the plant bitter extracts alone were not effective in reducing fat deposition. However, when combined with low doses of caffeine, these bitter compounds reduced the feed intake, increased carcass leanness, and improved the pork colour by intensifying the meat redness and yellowness. Increasing the dietary levels of BM linearly reduced carcass traits (i.e., backfat and weight) and growth performance (feed intake and weight gain), and increased meat colour intensity. The meat colour changes of BM-fed pigs were associated with changes in the abundance of energy metabolism and muscle structure proteins

Dietary bitter compounds such as caffeine have the potential to reduce backfat in pigs. However, the use of caffeine as a feed additive has restrictions in many countries. It was hypothesised that grape seed and gentian plant extracts (GG) could replace caffeine in feed due to their bitterness and antiadipogenic effects. The effect of caffeine (0.5 g/kg), GG (2 g/kg) alone or in combination with caffeine (BM) at increasing concentrations (0.5, 1, 1.5, or 2 g/kg) on feed efficiency, carcass, and meat quality was assessed in finishing pigs (Large White × Landrace). Growth performance and carcass traits were evaluated at a pen level (n = 14). Loins (longissimus thoracis) were removed from eight pig/treatment at the abattoir to assess drip loss, lightness (L*), redness (a*), yellowness (b*), chroma (C*), hue angle (h°), pH, cook loss, and shear force. A linear increase (p < 0.05) in loin a*, b*, and C* values and a linear decrease (p < 0.05) in ADFI, ADG, backfat, dressing percentage, and HSCW were observed with increasing BM levels. At 1.5 g/kg, BM increased the loins a* (p < 0.05), b* (p < 0.05) and C* values (p < 0.05) compared to the control. Twenty-two proteins related to energy metabolism and myofibril assembly were identified to be upregulated (FDR < 0.05) in BM vs. control loins. In conclusion, GG could be used in combination with low doses of caffeine to modulate appetite and carcass leanness and improve pork colour.