Dietary effects on growth, plasma lipid and tissues of rats fed with non‐conventional oil of Telfairia occidentalis

Abstract

AbstractThe nutritional value of Telfairia occidentalis seed and seed oil available in local market was studied in rats. The average values of the proximate analysis on dry matter basis were 203 g kg−1 crude protein, 536.3 g kg−1 fat, 39 g kg−1 ash, 95 g kg−1 crude fibre and 43.7 g kg−1 carbohydrate, while the moisture content was 75 g kg−1. The mineral analyses showed that T occidentalis seeds contain potassium (3280 mg kg−1), sodium (1230 mg kg−1), magnesium (60.8 mg kg−1), calcium (60.8 mg kg−1) and iron (13.0 mg kg−1). The oil extracted from the seed sample showed physicochemical properties that suggest its suitability for edible and industrial uses. The oil contained high levels of unsaturated fatty acids, oleic and linoleic, which accounted for 63.22% of total fatty acids recovered, while palmitic acid (27.4% of the oil by weight) was the most prevalent saturated fatty acid in the oil. No trace of eleostearic acid was detected in the oil. The effect on physical appearance, weight gain, organ weight, tissue and plasma cholesterol and triacylglycerol levels was determined in rats fed a diet containing 5% T occidentalis oil. These were compared with those of rats fed a control diet (0% T occidentalis oil) over an 8 week study period. Weekly monitoring of the rats showed good physical appearance and steady weight increase. The test rats were not anaemic and no mortality was recorded. While there was a significantly higher (p < 0.05) level of cholesterol in the heart of test rats compared with the control, there was a significantly lower (p < 0.05) plasma cholesterol level, suggesting that T occidentalis seed oil can be used to lower plasma levels of cholesterol. Histological examination of the sections of the heart, liver, kidney and spleen of the test rats revealed varying degrees of pathology. These include artherosclerotic changes in the walls of vasa vasori and lymphatics in the heart and hyaline degeneration of myofibrils, fatty infiltration of hepatocytes, and glomerular and tubular degeneration in the kidneys. These lesions may have been due to the effect of fatty acids, especially erucic acid, in the seed oil, which at 1.24% (less that the 5% conventional allowable limit for edible oils) may be intolerable for rats and may be unsuitable for human consumption. The seed oil may be used for industrial purposes such as soap making, lubrication and cosmetics for which it is well suited. Copyright © 2004 Society of Chemical Industry