Effect of Dietary Sorghum Distillery Residue on Hematological Characteristics of Cultured Grey Mullet (Mugil Cephalus)?an Animal Model for Prescreening Antioxidant and Blood Thinning Activities

Abstract

The sorghum distillery residue (SDR) has been an underutilized by‐product with estimated production of 150 ton/day in Kinmen, Taiwan. The objective of this study was to test for any physiological effects of SDR, thus to utilize it as a nutraceutical feed ingredient in diets for cultured fish. Hot air‐dried, wet, and dehulled‐wet sorghum distillery residue showed 63%, 90% and 97% inhibition of the hemoglobin‐catalyzed oxidation of linoleic acid compared to soybean (13%) and rice bran (78%). The feed formulated with 20% wet or dehulled‐wet sorghum distillery residue both showed an antioxidant activity of 68% being higher than the control diet (53%). Feeding these diets to cultured grey mullet for 60 days in summer (temperature ranged 24–30C), resulted in a lower hydroperoxide content in gill tissue, as shown by a chemiluminesence intensity of 1806 or 1409 mV as opposed to 2666 mV for fish fed a control diet. In winter, when the water temperature decreased to 14C, grey mullet fed a diet consisting of 10% dehulled wet sorghum distillery residue had a blood viscosity of 1.9 mPas and a hematocrit value of 33%, in contrast to 3.6 mPas and 41% for control. The blood of the control group started to aggregate in 6 h and showed hemolysis, while the mullet fed dehulled, wet sorghum distillery residue did not show blood aggregation, maintained normal fluidity and erythrocyte membrane integrity. It seems that cultured fish may have the potential as an animal model for prescreening antioxidant and blood thinning effects of food ingredients.

Inhibitory effect of Pistia tannin on digestive enzymes of Indian major carps: an in vitro study

“…Moreover, tannin not only affected the protease activity, but also inhibited comparatively lipase activities to a greater extent and amylase activities to a lesser extent. Lee and Pan (2003) indicated a non-competitive mixed-type inhibition of in vitro trypsin activity from grey mullet (Mugil cephalus) by tannin which may throw some light on possible inhibitory mechanism of such compound. Limited literature on this particular issue suggests that more effort should be given to gain a better insight to find out the mechanism of tanninmediated inhibition of digestive enzymes of fish and its probable effect at the physiological level.…”

Sorghum phytochemicals and their potential impact on human health

“…Lee and Pan (2003) demonstrated that dietary tannin-sorghum distillery residues inhibited 63-97% of hemoglobin-catalyzed oxidation of linoleic acid in cultured mullet fish compared to soybean (13%) and rice bran (78%). The authors also found that the sorghum residues significantly improved blood-thinning and erythrocyte membrane integrity of the fish blood cells during winter, thus maintaining normal blood fluidity and preventing RBC hemolysis induced by H 2 O 2 .…”

Sorghum: An Underutilized Cereal Whole Grain with the Potential to Assist in the Prevention of Chronic Disease

“…There may be an anticoagulant effect of sorghum tannins, yet to be tested in humans, as evidenced in cultured mullet fish that were fed tannin-containing sorghum distillery residues. (170) The sorghum residue significantly improved blood thinning and erythrocyte membrane integrity of the fish blood cells in cooler water temperatures over the winter months, enabling normal blood viscosity and prevention of red blood cell hemolysis induced by typical oxidation processes. The authors suggest that the antioxidant activity of the tannins and polyphenols present in the sorghum residue contributed to the prevention of red blood cell hemolysis.…”