Journal of Experimental and Integrative Medicine DOI: 10.5455/jeim.180115.or.119 www.jeim.org J Exp Integr Med ● Jan-Mar 2015 ● Vol 5 ● Issue 1 47 INTRODUCTION The beneficial health effect of dietary fish intake has been known for decades. The low incidence of cardiovascular disease among populations consuming fish rich diets has been attributed to a greater proportion of omega 3 polyunsaturated fatty acids in fish oil. The mechanism for the cardioprotective effect of fish intake may include anti-arrhythmic, anti- thrombotic, anti-inflammatory and hypotensive effects, and improved endothelial function; reduction of atherosclerosis plaque and antilipemic action [1,2]. Similarly, proteins and particularly their hydrolysates from different fish species have been proved to reduce serum cholesterol level in laboratory animals or human when compared with casein [3]. Hosomi et al. [4,5] have shown that dietary fish protein decreased serum and liver cholesterol contents. Moreover, Mellouk et al. [6] have also demonstrated in rats that sardine protein diet decreased significantly serum unesterified cholesterol, triacylglycerols (TG), very low-density lipoprotein (VLDL) and LDL mass with increase in high-density lipoprotein (HDL 2 ) mass. In the same way, several studies have indicated that protein hydrolysates can play a role as a cardioprotective by reducing serum cholesterol level and increasing cholesterol (C)-HDL [7]. Indeed, Khaled et al. [8] showed previously that supplementation of sardinelle protein hydrolysate to cholesterol-containing diet reduced significantly total cholesterol (TC), TG and C-LDL and increased C-HDL. These hypocholesterolemic and Sardina pilchardus and Sardinella aurita protein hydrolysates reduce cholesterolemia and oxidative stress in rat fed high cholesterol diet Nora Athmani 1 , Faiza Dehiba 1 , Amine Allaoui 1 , Ahmed Barkia 2 , Ali Bougatef 2 , Myriem Y. Lamri-Senhadji 1 , Moncef Nasri 2 , Ahmed Boualga 1 Original Article ABSTRACT Objective: The present study was designed to determine in rats fed high cholesterol diet whether serum cholesterol concentration and its distribution in lipoprotein fractions could be improved by sardine (Sardina pilchardus) and sardinelle (Sardinella aurita) protein hydrolysates. In addition, lipid peroxidation in different lipoprotein fractions and in two target tissues of atherosclosis and their antioxidant enzymes activities were also evaluated. Materials and Methods: Eighteen adult male Wistar rats (350 ± 15 g) fed 20% casein with 1% cholesterol were divided into three groups. Group I and Group II were designated as ‘sardine’ and ‘sardinelle’ groups received 300 mg of the respective fish protein hydrolysates for 14 days by oral gavage while the third group received water in the same conditions and constituted the control group (CG). Results: Compared with CG, cholesterolemia was 1.7-fold lower in sardine and sardinelle groups. This was meanly due to their reduced low-density lipoprotein- high-density lipoprotein (HDL 1 )-cholesterol contents while those of HDL 3 were enhanced. Thiobarbituric acid reactive substances contents were found to be lowered in red blood cells (RBC), heart and aorta of sardine and sardinelle group rats compared to CG. In the same groups, paraoxonase activity was also higher than CG. RBC and heart superoxide dismutase activity was higher in sardinelle group versus CG. In aorta, glutathione peroxidase activity was higher in both sardine and sardinelle groups. Glutathione reductase activity in RBC and aortic tissue was also increased in sardine and sardinelle groups. Conclusion: Sardine and particularly sardinelle protein hydrolysates could be considered as two bioactive ingredients with a potent cholesterol-lowering effect accompanied by efficient decrease in lipid peroxidation in serum and target tissues, related with increased antioxidant enzymes activity in rats fed a high cholesterol diet. KEY WORDS: Fish protein hydrolysates, hypercholesterolemia, lipoproteins, oxidant status, rat 1 Department of Biology, Laboratory of Clinic and Metabolic Nutrition, Faculty of Natural Life Sciences, University of Oran, Oran, Algeria, 2 Laboratory of Enzyme Engineering and Microbiology, National School of Engineering, Sfax, Tunisia, Africa Address for correspondence: Address for correspondence: Ahmed Boualga, Laboratoire de Nutrition Clinique et Metabolique, Faculte des Sciences de la Nature et de la Vie, Universite d’Oran, 31000 Oran, Algeria. E-mail: boualga.ahmed@ univ-oran.dz Received: Received: July 24, 2014 Accepted: Accepted: January 18, 2015 Published: Published: March 15, 2015