Dietary Resin Acid Concentrate Improved Performance of Broiler Chickens and Litter Quality in Three Experiments

SIMPLE SUMMARY: Resin acids are antimicrobial and anti-inflammatory compounds derived from spruce and pine trees. In a previous study, in which a mixture of resin acids and fatty acids from pine and spruce trees was added to the feeds of broiler chickens, they grew heavier, and their footpads stayed in better condition. Here, three separate trials were conducted to study whether dietary resin acids without the fatty acids have the same effects on broiler chickens. Broiler chicken diets were amended with different dosages of a resin acid concentrate product. Bird weight gain increased, and the efficiency of broiler production was improved when the resin acid concentrate was added to the diet at 125–250 g/ton. The litter material of pens stayed drier in resin acid concentrate groups, which may indicate better intestinal condition of the birds. However, the footpad condition was unaffected by the experimental diets. The results suggest that the resin acid concentrate improves bird weight gain and the efficiency of broiler production. Therefore, the resin acid concentrate may be a promising feed additive for broiler chickens. ABSTRACT: Dietary coniferous resin acids have previously been suggested to support the intestinal integrity of broiler chickens by reducing mucosal collagen degradation. The present study examined the effects of resin acid concentrate (RAC) on broiler performance and litter quality. In trial 1, RAC was added to diets at 0, 125, 250, or 1250 g/ton, while in trials 2 and 3, RAC dosing was 0 or 175 g/ton. Bird weight, feed consumption, mortality, feed conversion ratio (FCR), European Efficiency Index (EEI), litter moisture, and footpad dermatitis (FPD) lesions were measured. In trial 1, RAC at 125 and 250 g/ton improved weight gain and EEI, while RAC at 1250 g/ton group did not differ from control. Feed consumption, FCR, FPD scores and mortality were similar in all treatments, but litter quality was improved by all doses of RAC. In trials 2 and 3, RAC increased the final weight of birds, improved FCR, EEI, and litter quality, but had no effects in other parameters. In summary, RAC at 125–250 g/ton improved bird performance and thus shows promise as a feed additive. The dryer litter in RAC treatments may suggest improved intestinal condition as a response to in-feed resin acids.