Phenolic acids identified in sorghum distillery residue demonstrated antioxidative and anti-cold-stress properties in cultured tilapia, Oreochromis mossambicus.
This study aimed to identify the bioactive compounds and evaluate the anti-cold-stress function of the sorghum distillery residue (SDR) using tilapia as an alternative animal model. The highest contents of water-soluble bioactive compounds in SDR were polyphenols, followed by tannins, anthocyanins, and flavonoids. SDR was extracted with double-distilled water, 95% ethanol, and ethyl acetate, separately. The ethanol extract (SDR-E) yielded the highest polyphenol content [15.03 mg/g of SDR dry weight (dw)], of which the EC50 value of R,R-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging efficiency was 0.56 ± 0.04 mg/mL. The SDR-E suppressed the oxidation of low-density lipoproteins (LDLs) more efficiently than that of other extracts. Tilapia fed a diet containing 3.6% SDR-E decreased accumulative mortality during cold stress, of 46.2%. The accumulative morality of the control was 92.9%. The phenolic acids identified in SDR included gallic acid (0.36 ± 0.08 mg/g of SDR dw), 3,4-dihydroxybenzoic acid (0.16 ± 0.12 mg/g of SDR dw), and 4-hydroxybenzoic acid (0.49 ± 0.23 mg/g of SDR dw). Diets supplemented with 0.5% 4-hydroxybenzoic acid fed to tilapia showed a lower mortality rate than that fed 1.0% 4-hydroxybenzoic acid, comparable to that of the tilapia fed 20% SDR. The latter showed lower mortality than that of the control. These results suggested that 4-hydroxybenzoic acid is one of the major anti-cold-stress compounds in SDR.
Department of Food Science, National Quemoy University , Kinmen 892, Taiwan.
Shin-Mei
SM
Lee
Jing-Jen
JJ
Lin
Chih-Yuan
CY
Liao
Hui-Ling
HL
Cheng
Bonnie Sun
BS
Pan
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D003080:Cold Temperature; D057168:Distillation; D062385:Hydroxybenzoates / Q000737:chemistry / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism*; D045868:Sorghum / Q000737:chemistry*; D017210:Tilapia / Q000254:growth & development / Q000502:physiology*; D014866:Waste Products / Q000032:analysis*
D000975:Antioxidants; D062385:Hydroxybenzoates; D010936:Plant Extracts; D014866:Waste Products; C017616:phenolic acid