l n d ian Sard i rae o i 8 (Sardd'neila bongiceps) as a Source of Omega-3 Fatty Acids

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1 Short Communication l n d ian Sard i rae o i 8 (Sardd'neila bongiceps) as a Source of Omega-3 Fatty Acids K. Ambasankar* and V. Balakrishnan Department of Animal Nutritron Madras Veterinaly College, Chennai , India (Received May 02,2005) ABSTRACT Amnhasankar, K. and Balnkrishnan, V. 2006, Indian sardine oil lsardirie1la longiceps) as a source of omega- 3 fatly acids. Animal Nuu-izion and Feed Technoios, 6: Nutritional evaluation of sard~ne oil (Surdinella io~lgiceps) was carried out to explore the possibility of including ir in ruminan diets to develop value added produce. Physical evaluation revealed that sardine oil is light yellow to darker brown in colour with Ashy odour and having a mean specific gravity of Fatty acid profile revealed significanr amount of eicosapentaenoic acid (13.18 k0.75 9) and docosahexaenoic acid ( %), indicaring its utility as an omega-3 source. The gross energy was kcallkg. The acid value was 13.29k1.02 mg KOHlg and the iodine value was The higher saponification number ( ) coupled with lower unsaponifiable matter (1.229=0.0589) signified its suitabiliy to form soaps and to use it as a protected fat supplement, at higher level of incorporation in the ruminant diets. As sardine fish oil is a very rich source of omega-3 fatty acids, it could open avenues for modifying the fatry acid composition of milk and meat of ruminants. Keywords: Chemical characrerisrics, Fatry acid profile, Fish oill, Sardine. INTRODUCTION There is increasing information about the nutritional and health benefits of long chain omega-3 or n-3 poly unsaturated fatty acids (PUFA) for humans (Simopoulous, 1998). In this context omega-3 PUFA especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can play very important role. The major benefit derived from EPA and DHA are reduced risk of cardiovascular diseases, enhanced development of brain and visual acuity in infants, and modulation of auto immunity (Calder, 1998). These omega-3 PUFA occur in many fish oils, and species containiilg high proportion *~e~rint requesr: Dr. K. Ambasankar, Tel: : Fax: : drarnbasan@yahoo.com

2 AmbasanSr and Balakrishnan of rhese acids could be commercially valuable. The fatty acid compositioa more common marine food fishes of the Indian coast has been reported (Gopakumar and Rajendranathan. 1975). The Indian oil Sardine which enjoys the pre eminent position in Indian marine fisheries is mainly caught from the coastal waters of Kerala and Karnataka and to some extent from Goa and southern Maharastra on the west coast. In India, fish oil is mainly extracted from the oil Sardine and is currently used as drying oils and in varnishes. It is also used as lubricating greases and waterproofing agents. In poultry, it is used as energy source. The higher EP.4 and DH.4 content in marine fish oils signifies their potential for developing value added produce in ruminants by using it in the form of protected fat (Fievez et al., 2003; Kitessa et al., 2003). Hence, an attempt was made to analyse the nutritional attributes of sardine fish oil as source of omega-3 fatty acids for its potential use in the ration of ruminants. MTEHPIALS MW METHODS Ten samples of sardine oil was collected from different sardine oil producing units in the west coast of India. Antioxidant, butylated hydroxytoluene, was added to the sardine oil immediately on arrival at 0.01 % level to protect against oxidative rancidity, flushed with nitrogen and stored in air tight containers in a cool dark place until further analysis. The samples were further evaluated for their physical qualities namely colour, odour and specific gravity. The samples were analysed for moisture. CP, total ash and free fatty acids as per AOAC (1997). The ether extract was estimated by difference i.e., 100-(moisture + CP +total ash). Gross energy was estimated using bomb calorimeter (Parr Bomb, Model 1620, USA). The chemical characteristics of the sardine oil in terms of acid value: saponification number, unsaponifiable matter; peroxide value and iodine value was carried out as per AOAC (1997). The fatty acid profile of collected sardine oil was analysed by first converting it into fatty acid methyl esters (Wang et al., 2000) and then analyzing it using a gas chromatograph SPTM-2380 capillary column 30m x 0.2 mrn x 0.2 pm film thickness. The oven temperature was programmed at 160 C for 3 min and was increased at 5 C per min so as to attain a maximum temperature of 220 C. At this temperature it was retained for seven min. The detector and injector temperature was set at 250 C. The carrier gas used was nitrogen and the split ratio was 50:l. RESULTS Ah9 DISCUSSION The physical evaluation of sardine oil revealed that the colour varied from lighter shades of yellow to darker shades of brown. Such brown and yellow colour of Sardine oil with dark and light shades has been reported by earlier workers (Kamasastri, 1961; Madhavan and Kaimal, 1968). Majority of the collected samples (80%) were having the specific fishy odour which is attributable to the presence of volatile compounds in the oil (Hsieh et al., 1988). Rancid and offensive odour was also observed in 10% of the samples.

3 Sardine oil as Omega-3 fatty mean specific gravity of the collected sardine oil was *0.003 which is in close agreement with earlier reports (Kamasastri etal., 1964: Madhavan and Kairnal 1968; and Gunstone et al., 1995). Chemical compos~tion of Sardine oil (Table 1) revealed that it had 99.31% ether extract, indicating that it was fairly pure with less impurities. The higher ether extract content in sardine oil reflected in the higher gross energy content (8801 k45.56 kcalikg), and thus indicating that it has a potential to be included as a energy supplement for livestock. The free fatty acid content varied from 4.99 to 9.06% with a mean value of 7.42%. The present values are simlar to the value of ( %) reported by Kamasastri (1961) in laboratory prepared sardine oil. The higher free fatty acid usually observed due to improper storage or handling of fat. The mean acid value of sardine oil (13.29k1.02 mg KOHlg) was higher than the value ( ) observed by Xarnasastri et al. (1964) in laboratory prepared sardine oil. Since the acid value indicates the proportion of free fatty acids contained in oils, the findings of present study revealed low proportion of free fatty acids in collected samples. The iodine value of sardine oil was However, very wide variation in lodine value was reported in sardine oil. Madhavan and Kaimal (1968) reported a lower value of 99 but a higher value of was reported by Sen and Chaluvaiah (1968). The probable variation reported in the literature was arrribured to the season. The iodine value of sardine oil indicates that it had higher degree of unsaturated fatty acids as iodine number directly reflects the degree of unsaturarion. Saponification number (206.29k1.47) observed in this study lies in the range of to reported by earlier workers (Kamasastri,l961; Kamasastri et al., 1964; Madhavan and Kaimal, 1968; Gunstone er al., 1995). Unsaponifiable matter refers to the material, which is soluble in petroleum ether but does not react aith sodium or potassium hydrolysis to form soaps. This includes wide variety of compounds such as steroids, pigments, fat soluble vitamins, fatty alcohols, fatty-fatty esters, waxes, mineral oils, pesticides, etc. The value of 1.2% unsaponifiable matter estimated in this study lies between the reported values of per cent (Kamasastri 1961; Table 1 Composition and chermcal attr~butes of sardlne oil' Composition+ MeaniSE Chem~cal characters* MeaniSE Molsrure (5%) Acld value (mg KOH!g) 13 29il 02 Crude protein (8) 0 15 c0 01 Saponification Kumber ETher extract (8) t 0 03 Unsaporufiable marter (70) Toral ash (%) Peroxide value (meq 0,ikg) 10 69iO 70 Free famr acld (%) 7 42 f 0 46 Iodlne value Gross energy (kcallkg) 8801 k45 56 'Mean of ten samples, *On DM bas~s, 6on fresh-bas~s 285

4 Ambasankar and Balakrishnan Table 2. Fattj acid protile (gi100 g) of sardine oil on as fresh basis7 Fatty acid a Per cent content Myr~stic acid (C!,,,) Pentadecanoic acid (C,,,) 0.18 z 0.02 Palmiric acid (C,,,) i 0.46 Palmit oleic acid (C,,,) Margaric acid (C,,J Srearic acid (C,,,) 4.91? 0.50 Ole~c acid (C,, :) 9.60 i 0.36 Linoleic acid (C,,,) 1.04 k 0.11 Linolenic acid (C,,,) 1.32 rt 0.91 Octadecatetraenoic acid (C,,,,) 0.44 k 0.05 Gadoieic acid (CZ0,) 2.47 i 0.13 Arachidonic acid (C,:,) Eicosapentaenoic acid (EPA; C,,,) & 0.75 Erucicacid (C2Z,) 1.35 C 0.37 Docosatetroenoic acid (C,,,,) Docosahexaenoic acid (DI-L4;), C, : Mean of ten samples Madhavan and Kaimal, 1968). Unsaponifiable matters contribute very little to the energy value of feed fat. A low value is indicative of wholesomeness. The higher saponification number coupled with lower unsaponifiable marrer appears to be good candidature to develop protected fat from sardine oil to use in ruminant ration as calcium salts of sardine oil. Peroxide value of meq O,/kg obtained in the current study indicates that the sardine oil rich in polyunsaturated fatty acids is prone to oxidative rancidity. The fatty acid profile of sardine oil is presented in Table 2. The predominant fatty acids are the palmitic (C,) 22.64%, followed by EPA 13.18%, palmitoleic acid (C!,,,) %, DHA % and oleic 9.61%. The presence of fair amount of EPA and DHA in sardine oil indicates that it is a good source of omega-3 fatty acids. The EPA content ranged from 9.94 to 16.39% while the DHA content ranged between 9.19 and 15.98%. The mean EPA content found in this study was slightly higher than the value of 10.60% reported by Gopakumar and Rajendranathan (1975). However, Fievez et al. (2003) and Keady and Mayne (1999) reported much higher values of and 19.00%, respectively, in fish oils. The mean DHA content obtained in this study was similar to the reported value of (10.80%) by Keady and Mayne (1999) and Fievez et al. (2003). The variability in EPA and DHA contents was attributed to the source. Even though the EPA and DHA content were variable, the total omega-3 fatty acid content in the sample ranged berween to 28.95%. A higher proportion of

5 Sardine oil as Omega-3 fatry acids acid possess potential for tailoring the fatty acid composition of milk and meat through feeding of sardine oil by protecting the omega-3 rich PUFA from rumen bio-hydrogenation by suitable method. In conclusion, nutritions 1 analysis of sardine oil indicated that it is a very good source of omega-3 fatty acids especially the EPA and DHA and, therefore, has got the potential for facilitating tailor made products in ruminant produce by including in the form of protected fat supplement. ACKNOU'LEDGEMENT The first author is grateful to the Director, CIBA. for granting study leave and Dean, Madras Veterinary College, for providing necessaq facilities to carry out this work as part of the PhD thesis. REFERENCES AOAC Wcial Methodr ofanalysis, 18th ed..4ssocianon of Official Analytical Chemists, Washington DC. Calder, P.C Fat change of immuno modulation trends. Immunology To&, 19: Fievez, V., Dohme, F., Danneels, M., Raes, K. and Demeyer, D Fish oil as potent rumen methane inhibitors and associated effects on rumen fermentation in vitro and in vivo. Animal Feed Scrence and Technology, 104: 41-38, Gopakurnar, K. and Rajendranathan, M Studies on the biochemical composition of some fresh water flishes. 11. Faq acid composition of lipids of oil sardine (Sar-dinella Iongiceps). Fishery Technology, 3: Gunstone, F.D., Hardwood, J.L. and Padley, F.B The lipid Hand Book, 20C ed. Chapman and Hall, Madras, India. Hsieh, T.C.Y., Williams, S.S., Vejaphan, W. and Mayers, S.P Characterization of volatile components of menhaden fish oil. Journal of American Oil Chemistry Sociey, 66: Kamasastri, P.V Studies on Indian Sardine oil. Indian Journal of Fisheries. 7: Kamasashi, P.V., Prabhu, P.V, and Rao, D.R Further studies on Indian Sardine oil. Indian Journal of Fisheries, 9B: Keady, T.W.J. and Mayne, C.S The effect of level of fish oil inclusion in the diet on rumen digestion and fermentation parameters in cattle offered grass silage based diets. Animal Feed Science and Technology, 81: Kitessa, S.M., Peake, D., Bencini, R. and Willams, A.J Fish oil metabolism in ruminants Transfer of n-3 polyunsaturated fatty acids (PUFA) from tuna oil into sheep's milk. Animal Feed Sciellce and Technology, 108: Madhavan, P. and Kaimal, M.N.N Utilisation of Sardine oil. Paint India, 18: Sen, D.P. and Chaluvaiah, G.L Sardine oil: its extractions and properties. Painr India, 18: Simopoulous, A.P The return of &3 into food supply. I. Land based animal products and their health effects. Proceedings of the International Conference on the Rerum of 0-3 FaQ Acids irrro the Food Supply, Sept 18-19, '1997, Karger, Basel, Switzerland. U'ang, Y., Sunwoo, H., Cherian, G. and Sim, J.S Fatry acid determination in chick and egg yolk: A comparison of different methods. Poufrry Science, 79: