Final & Given Synopsis

Download Final & Given Synopsis

Post on 27-Oct-2014




0 download

Embed Size (px)


<p>PUNJAB AGRICULTURAL UNIVERSITY Synopsis of Thesis Problem of Post-Graduate Student: Ph.D.</p> <p>Name</p> <p>:</p> <p>SONU Zoology Dr. (Mrs.) G.K. Sehgal</p> <p>Admission No. Minor Subject</p> <p>: :</p> <p>L-2010-BS-72-D Biochemistry</p> <p>Major Subject : Major Advisor :</p> <p>1. Title of the research problem EFFECTS OF SOME ALTERNATIVE DIETARY LIPID SOURCES ON FATTY ACID PROFILES AND PROXIMATE COMPOSITION OF COMMON CARP, Cyprinus carpio (Linn.). 2. Introduction Demand for fish is constantly increasing as humans are becoming more and more health conscious. They prefer to consume nutritious food with added health benefits. Fishes possess both these qualities and are, therefore, considered as health or functional food. Fishes are the best source of longchain (LC) polyunsaturated fatty acids (PUFAs), mainly the n-3 and n-6 PUFAs. The n-3 PUFAs are known to be cardio-protective (Sanderson et al, 2002), anti-atherosclerotic (Givens et al, 2006), antithrombic (Calder, 2004) and anti-arrythmatic (Givens et al, 2006). Besides, they have high protein content (15-25%), which is required for maintenance and growth of human body. Fishes are rich in vitamins A, D, E and K and minerals (calcium, phosphorus and iron). Compared to beef, mutton and chicken, fish meat is more digestible as it contains much less connective tissue (Calder, 2004). The increased demand of fish can be met from aquaculture as the capture fisheries is towards decline. World capture fisheries decreased from 92.4 million metric tonnes (mmt) in 2004 to 90 mmt in 2009. The world aquaculture production, on the other hand, markedly increased from 15.3 mmt in 2004 to 21 mmt in 2009 (FAO, 2010). Therefore, aquaculture, with per capita supply increasing from 0.7 kg in 1970 to 7.8 kg in 2008, with an average annual growth rate of 6.6% (FAO, 2010), is the only hope. However, aquaculture largely depends upon capture fisheries for fish meal and fish oil used in aquafeeds. Fish oil has a high level of n-3 highly unsaturated fatty acids (n-3 HUFA), particularly, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have high health value for fish and human beings. Since aquaculture is expanding and capture fisheries is contracting, the supply of fish meal and fish oil is becoming limited and hence more expensive. It has created pressure on the aquafeed manufacturers to 1</p> <p>replace these ingredients with some sustainable alternatives (Pickova &amp; Morkore, 2007). Vegetable oils have potential to replace substantial amount of fish meal/fish oil in the diets of many fish species without affecting their growth and feed efficiency. However, their effect on nutritional value of fish in terms of fatty acid profiles and proximate composition of flesh is largely unknown, although oils derived from unicellular algae, pelagic organisms or benthic invertebrates containing high amounts of n-3 HUFA have been identified and tested in aquafeeds (Hertrampf &amp; Piedad-Pascual 2000, Carter et al, 2003 and Olsen et al, 2004). Nevertheless, their prices are still too high to be commonly used in aquafeeds (Turchini et al, 2009). Thus, it is important to study the impact of vegetable oils and animal fats on the growth performance and, more importantly, on the fatty acid and proximate compositions of the edible part of the fish fed these oils/fats. Realizing the need for the use of vegetable oils and/or animal fats as fish feed ingredients, some work in this direction has been done quite recently. The fish species which have been studied include rainbow trout (Brown et al 2010, Guler and Yildiz 2011 and Trushenski et al, 2011a), cobia (Trushenski et al, 2011c), pike perch (Kowalska et al, 2011), Oncorhynchus mykiss (Twibell et al 2011), Atlantic salmon (Menoyo et al 2005), Huso huso (Hosseini et al 2010), Litopenaeus vannamei (Gonzalez-Felix et al 2010). No such study has been done on carps, which are important freshwater food fishes forming about 86% of the Asian aquaculture, which contributes more than 85% to world fish production. The present study is therefore, proposed to identify a vegetable oil and/or animal fat which is capable of completely or partially replacing fish meal/fish oil without compromising with nutritional quality and fatty acid composition of common carp, Cyprinus carpio (Linn.), an important freshwater food fish. Knowledge gaps There is scanty information on the alternative lipid sources including vegetable oils/animal fats which can replace fish meal/fish oil from aquafeeds. This information is completely lacking with respect to carps, which are one of the important freshwater food fishes cultured in Asia, India and Punjab. Objective To identify alternative lipid source(s) for complete/partial replacement of fish meal/fish oil from the feed of common carp without compromising with the growth performance, and nutritional quality (fatty acid profiles and proximate composition) of the fish.</p> <p>2</p> <p>3. Expected new knowledge New knowledge on whether or not vegetable oils and/or animal fat can completely/partially replace fish meal/fish oil from carp feed, without affecting its growth performance and nutritional quality (fatty acid profiles and proximate composition), shall be generated. 4. Review of literature Studies on the use of alternative dietary lipid source and their efficiency to replace fish meal/fish oil from aquafeeds have been conducted quite recently on non carp species. The effects of dietary lipid source and n-3 highly unsaturated fatty acids (n-3 HUFA) level on growth, body composition and blood chemistry of juvenile starry flounder was investigated by Lee et al (2003). The contents of n-3 HUFA in fish linearly increased with increasing dietary squid liver oil. Results indicated that dietary n-3 HUFA were essential and a value of at least 0.9% of n-3 HUFA in the diet could be recommended for optimum growth and efficient feed utilization of juvenile starry flounder. The twin problems of fish oil (FO) replacement with vegetable oil (VO) and high energy diets in salmon throughout the entire production cycle was investigated Tocher et al (2003). Fatty acid compositions of liver, intestinal tissue and gill were altered by the diets with increased proportions of C18 polyunsaturated fatty acids and decreased proportions of n-3 HUFA in fish fed VO compared to those fed FO, HUFA synthesis in hepatocytes and enterocytes was significantly higher in fish fed VO, whereas oxidation was unaltered by either of the dietary oil content or type. Over the entire production cycle, HUFA synthesis in hepatocytes showed a decreasing trend with age, interrupted by a large peak in activity at seawater transfer. Gill cell prostaglandin (PG) production showed a possible seasonal trend, with peak activities in winter and low in summer and at seawater transfer. The PG production in seawater was lower in fish fed the high-oil diets with the lowest PG production generally observed in fish fed high VO. The changes in fatty acid metabolism induced by high dietary oil and VO replacement contributed to altered flesh lipid content and fatty acid compositions. Similarly, Turchini et al (2003) evaluated the effects of alternative dietary lipid sources (fish oil as controlC; canola oilCO; poultry fatPF; pork lardPL; and oleine oilOO) on performance, tissue chemical composition, mitochondrial fatty acid oxidation capabilities and sensory characteristics in brown trout (Salmo trutta L.) over 70 days at 14.60.4 C. The best growth was observed in fish fed the C diet whereas the PL diet fed fish had the best feed utilization. The fatty acid composition of muscle largely reflected that of the diets, while total cholesterol was not affected. This study showed that alternative lipid sources could be used effectively for oil coating extruded diets for brown trout. Berge et al (2004) examined effects of different levels of dietary conjugated linoleic acid (CLA) on the growth and body composition of 0.7 g Atlantic salmon fry. Groups of fish were fed diets 3</p> <p>containing 0%, 0.5%, 1.0% or 2.0% CLA for a period of 12 weeks. CLA did not have a significant effect on the growth rate or on the proximate composition of salmon fry, even though there was a trend towards higher final weight in the fish fed the 1% CLA diet. The fatty acid composition was strongly affected by diet. CLA was deposited in the fish. Dietary CLA also affected the deposition of other fatty acids. The deposition ratio (RD) values of 14:0, 16:0 and 18:0 fatty acids increased, while those of 16:1 and 18:1 fatty acids decreased, in response to increasing levels of CLA in the diets. This suggests that CLA causes a reduction in D-9 desaturase activity. Dietary CLA caused a significant increase in the RD values of total n-3 fatty acids, especially that of 22:6n-3. CLA also caused a higher concentration of phosphorus (P) and calcium (Ca), and a lower P/Ca ratio in the fish. The results showed that dietary CLA may alter fatty acid metabolism and bone mineralization. Suitability of two plant based lipid sources, canola oil (CO) and linseed oil (LO), as alternatives to fish oil for juvenile Murray cod was determined by Francis et al (2006). The fatty acid composition of Murray cod fillet was reflective of the dietary lipid source. Fillet of fish fed the FO had highest EPA, Arachidonic acid (ArA) and DHA. Fish fed the CO diet had high concentrations of oleic acid (OlA) (192.210.5 mg g1lipid), while the fillet of Murray cod fed the LO diet was high in -linolenic acid (LnA) (107.16.7 mg g lipid1). This suggested that FO can be replaced by up to 100% with canola oil and by up to 50% with linseed oil in Murray cod diets with no significant effect on growth. An experiment in which fillets of trout fed a diet containing either 200 (low vitamin E [LVE] diet) or 5000 (high vitamin E [HVE] diet) mg a-tocopheryl acetate/kg for 0, 4, and 9 weeks was conducted by Jittinandana et al (2006). These fillets were evaluated fresh and after 6 months of frozen storage. Frozen fillets were thawed and stored for 3 days at 1 C before analyses. Muscle -tocopherol of fish fed the HVE diet continuously increased through 9 weeks of feeding. Reduced muscle -tocopherol and moisture, and increased muscle redness and fat were observed in frozen-refrigerated fillets compared with fresh fillets. Thiobarbituric acid-reactive substances were lower in frozen-refrigerated fillets produced from fish fed the HVE diet. Proportion of unsaturated fatty acids and omega-3 fatty acids increased as feeding duration increased from 0 to 9 week. Kleveland et al (2006) investigated effects of in vivo administration of 3-thia fatty acids (FAs) on lipid metabolism in muscle and liver of Atlantic salmon. The fish were fed fish meal (FM) and fish oil (FO) - based diets supplemented with either nothing (FO), or 0.3% and 0.6% of the 3-thia FAs dodecylthioacetic acid (DTA) and tetradecylthioacetic acid (TTA) respectively. None of the 3-thia FA diets affected lipid content of the salmon muscle. The liver index was significantly higher and the total liver fat content was lower in the TTA group than in the FO group. Both DTA and TTA were incorporated into the lipid fraction of muscle and liver (0.4% to 0.9%). There were no major differences</p> <p>4</p> <p>in the total FA composition of liver and muscle between the dietary groups; except for a small increase of n-3 PUFAs in liver of the DTA group. Effect of diets enriched with 6 desaturated fatty acids (18:3n6 and 18:4n3), on growth, fatty acid composition and HUFA synthesis in two populations of Arctic charr (Salvelinus alpinus L.) was examined by Tocher et al (2006). Dietary Echium oil (EO) had no detrimental effect on growth performance and feed efficiency, mortalities, or liver and flesh lipid contents in either population. The proportions of 18:2n6 (Linoleic Acid), 18:3n3 (Alpha-Linolenic Acid), 18:3n6 (Gamma-Linolenic Acid), 18:4n3 (Stearidonic Acid), 20:3n6 (Dihomo-Gamma-Linolenic Acid) and 20:4n3 (Arachidonic Acid) in total lipid in both liver and flesh were increased by dietary EO in both populations. However, the percentages of 20:5n3 (Eicosapentanoic Acid) and 22:6n3 (Docosahexanoic Acid) were reduced by EO both in liver and flesh in both strains, whereas 20:4n6 (Arachidonic Acid) was only significantly reduced in flesh. In fish fed FO, HUFA synthesis from both [1-14C] 18:3n3 and [1-14C] 20:5n3 (EPA) was significantly higher in the planktonivorous Coulin charr compared to the demersal, piscivorous Rannoch charr morphotype. However, HUFA synthesis was increased by EO in Rannoch charr, but not in Coulin charr. Dietary EO had differential effects in the two populations of charr, with HUFA synthesis only stimulated by EO in the piscivorous Rannoch morphotype, which showed lower activities in fish fed FO. A Ten-week experiment on Japanese sea bass (5.870.02 g) to study the effects of replacement of fish oil with six alternative lipid sources: pork lard, PL; beef tallow, BT; poultry fat, PF; soybean oil, SO; corn oil, CO; and a mixed-fat (MF: tallow, 60%; soy oil, 20%; fish oil, 20%) on growth performance and fatty acid (FA) composition in fillet and liver was conducted by Xue et al (2006). Weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), feed intake and hepatosomatic index (HSI) of fish fed the experimental diets were not significantly different. Protein efficiency ratio (PER) in fish fed the PF diet was significantly lower than in those fed SO and CO diets. Significant differences in carcass moisture and lipid contents of carcass and liver were observed among fish with different dietary treatments. The fatty acid composition of fish fillets and livers reflected the dietary FA composition. Similarly, Yilmaz and Genc (2006) conducted 60 days feeding trial to determine the effect of increasing alternative dietary lipid [soyacid oil (SAO) and yellow grease (YG)] levels on growth performance, body composition and liver morphology of common carp. Seven isonitrogenous practical diets were formulated to contain 4, 8.5, 13, 18% SAO and 4, 8.5, 13% YG and the control diet without supplementation with dietary oil. Growth performance of fish fed diet containing 8.5% YG showed the best weight gain and was similar to the control group in respect to feed conversion, daily feed intake, protein and, energy consumption. No improvement was found in growth parameter in SAO-fed groups. In addition, liver</p> <p>5</p> <p>lipoid degeneration (steatosis) was observed in fish fed with the highest dietary lipid content. The results indicated that common carp did not efficiently utilize SAO and YG as alternative dietary lipid source. Blanchard et al (2008) evaluated the effect of different n-3 to n-6 ratios, underlying the effect of Linoleic Acid (LA) and Lenolenic Acid (LnA) levels, on growth performance, tissue fatty acid composition and hepatic ultrastructure of Eurasian perch. An increased proportion of 18:2n-6 (Linoleic Acid) and 18:3n-3 (Lenolenic Acid) in the diet of Eurasian perch...</p>