飼料中不同蛋白質含量對老鼠攝取油炸殘油之營養及毒性研究

Abstract

油脂經長時間高溫加熱處理後，不但改變其營養價值且產生多種有毒物質，使供試動物有生長減緩，內臟重量增加和其他不正常情形。以油炸殘油餵老鼠時，若供試老鼠之營養狀況不同，對此毒性油將顯現出不同的影響。本研究係將新鮮黃豆油以205±5℃溫度，油炸麪粉片，經每日六小時連續油炸四天後，處理所得之殘油，加入不同酪蛋白含量之飼料中，飼餵離乳後一週齡的Long-Evans品系老鼠。飼料中油添加量為15%，蛋白質含量分別為8, 15, 22%等不同含量，另在22%蛋白質飼料中分別再添加Methionine和維生素E兩種營養素，以探討蛋白質之營養性與Methionine，維生素E可能之效應。 實驗八週，其結果顯示如下： 1.攝取油炸殘油之供試老鼠，在第七週起有下痢的情形，第八週時則有不同程度的脫毛現象，且毛髮變粗，色澤較差。 2.供試老鼠體重的增加，對攝取新鮮油組，除低蛋白組外，餘15、22%蛋白質飼料間無明顯差異，唯織加Methionine組者有較高的蛋白質效率。對攝取油炸殘油組，則皆比攝取相同量蛋白質之新鮮油組之老鼠體重要輕。 3.內臟器官之病理觀察，顯示食用油炸殘油各組之肝、腎皆有腫大情形，尤以低蛋白質(8%)組為甚，各攝取殘油組中，以添加Methionine者，其肝、腎相對重量最小，有緩和肝或腎腫大情形。各組攝取油炸殘油者其脾之相對重量反而較新鮮油者小，有萎縮情形。 4.肝臟、小腸之組織切片檢查，顯示出無明顯不正常現象。 5.各組老鼠血液分析結果顯示，攝取油炸殘油組之GOT、GPT酵素活性都比攝取新鮮油組高，尤其以8%蛋白質之油炸殘油組者，增加最多，可知肝功能已受損；血球比容，則攝取油炸殘油者比同量蛋白質之新鮮油組低；全血比重，血清比重、血紅素比，除低蛋白質油炸殘油組降低外，其餘各組均無明顯差異。 綜合實驗結果，證實油炸殘油確可造成動物體的不良反應，包括體重減輕、下痢、脫毛、肝功能受損等。此種不良的反應，可因供試本身的蛋白質營養狀態改善，如質與量的增加，而獲得減緩。但若營養狀態不佳時，如質與量皆不佳，則不良反應更為嚴重，在本實驗中，Methionine之添加有助於改善攝取油炸殘油所產生的不良影響；而維生素E的添加則效果不顯著。 This study was made to learn the deleterious effects of residual deep-frying oil on the growing rats with various protein intakes. Weanling rats of Long-Evans strain were fed with test diets containing 15% either fresh or residual deep-frying soybean oil with 8, 15 and 22% dietary protein level respectively. The effects of methionine or vitamin E supplementation were also observed. During 8-week feeding period, the appearance, body weight change, feed efficiency and protein efficiency ratio of test animals were examined. At the end of test period, animals were sacrificed and their blood and organs were secured for clinical and biochemical analyses, and results revealed that: 1.Regardless of protein intake, most rats fed with diet containing residual deep-frying oil developed diarrhea at seventh week, and showed rough and oily hair at the eighth week. 2.Growth retardation was found commonly in rats fed with residual deep-frying oil. Lower protein intake would aggravate such phenomnon. 3.It was found that liver and kidney enlargement occurred in animals fed with residual deep-frying oil, particularly with low protein intake. With methionine supplementation, some protective effect was shown in animals fed with deep- frying oil. On the other hand, smaller speen was shown in these animals and was not affected by methionine supplementation. 4.Histological examination revealed no apparent abnormal changes in both liver and intestine tissues. 5.The SGOT and SGPT of residual oil fed rats appeared to be higher than their controls, especially the low protein (8%) intake group. Serum protein and hematocrit of these animals also appeared to be lower. The adverse effect of residual deep-frying oil shown in present study can be compensated in part by the improved protein intake. With methionine supplementation, some protective effect can be obtained. Nevertheless, vitamin E appeared to be ineffective.