Biochemical and Nutritional Nvestigations of Bangladeshi Fresh Water Fish Puntius Gonionotus

Abstract

Bangladesh is one of the developing countries of the world. A large number of populations in Bangladesh have been suffering from malnutrition. To over come this problem, it is necessary to increase the production of protein rich food for her peoples. Most of the people of the developing countries are still dependent almost entirely on fish as a source of animal protein. In Bangladesh, fishes are common as well as cheap sources of protein, fat, mineral and some vitamins. It is said “Rice and Fish” is the staple food of the people of Bangladesh. Therefore, optimum utilization of fishes, rich in nutrients, is of paramount importance to minimize micronutrients gap and thereby it is possible to improve nutritional status in the country. Puntiusgonionotus(P. gonionotus, locally known as China punti) fishes are being used as popular sources of fishes in some parts in Bangladesh. This fishes are found in Bangladesh mainly in the district of Pabna, Rajshahi, Bogra and Natore. Fishery of this fishes was carried out in three different ghers (polders). No remarkable change was found in pH, temperature and densities of water bodies used as fish habitat of these study areas. Total dissolve solid (TDS), electrical conductivity (EC), salinity and free CO2 were found maximum (22.3± 1.12 g/L; 33.85±0.82 ms/cm; 22±2.45 ppt, and 5.5±0.04 mg/L respectively) whereas hardness (mg CaCO3/L); Ca2+ (mg/L); Mg (mg/L); dissolve oxygen ((mg/L) and total suspended solid (TSS) (g) were found minimum (630±2.54; 70±2.46; 110.75±4.75; 5.6±0.04 and 0.020±0.01 respectively) CO2 and dissolved oxygen (D.O) are reliable for this fish culture but hardness’s were so high and may be concerned for the fish habitats. Alkalinity and chemical oxygen demand (COD) were found maximum (200±3.56 mgCaCO3/L and 140±1.88 mg/L respectively). Different types of gears and crafts were found for fishing P. gonionotus fishes in these ghers and in the river during full moon. Fishermen handover their catches in different distannce and nearby market through a more or less distinguish channel. In between the fishermen and final consumers there are a few intermediates. The market price and landing of fish varied marginally from market to market. The price of this fish to the consumer varies from season to season. In the fishery, xiv maximum labour force is employed in the traditional sector. They have normally large family members. The fishermen of these areas are mostly poor and illiterate. The proximate composition of flesh of this fish was determined using standard methods of analysis. The grand mean values were moisture 71.51±0.93%; protein 22.21±0.92%; lipid 5.24±0.64%; ash 1.02±0.05%; crude fibre4.655±0.32% and dry matter 28.50±0.65%. The analytical properties of the crude lipid were evaluated. It was observed that lipid was reddish brown colour and density and refractive index of the lipid were 0.9516 g/cc and 1.4612–1.4635 respectively. Studies on the chemical characteristics of this fish lipid indicated that the iodine value (I.V), saponification value (S.V), saponification equivalent (S.Eq.), acid value (A.V), ester value (E.V), peroxide value (P.V), percentage of free fatty acids (as oleic) were found to be 108.72; 186.52; 296.52; 1.96 mg/KOH; 235.29; 1.78 mEq/Kg; 1.78 % respectively. The lipid is found to be edible as its acid value was estimated to be low (1.96 mg/KOH). The chemical indices indicate that the fish is a good source of protein. This fish contained several dietary minerals such as calcium (Ca), magnesium (Mg), sodium (Na), phosphorus (P), potassium (K), iron (Fe), copper (Cu) and zinc (zn). The macro mineral elements calcium (Ca), sodium (Na), potassium (K), magnesium (Mg), and phosphorus (P) were found to be in the range of 276±4.54 mg; 76.01±2.16 mg; 294.4±2.01 mg; 48.1±1.83 mg and 210.0±1.80 mg per 100 g portion respectively. The micro minerals, iron (Fe), copper (Cu) and zinc (Zn), content in this fish were varied from 1.70±0.16 mg; 1.01±0.20 mg; 3.80±0.82 mg per 100 g portion respectively. The observations in dietary minerals suggested that the fish P. gonionotuscould be provided a significant proportion of calcium (Ca), magnesium (Mg), sodium (Na) and also potassium (K). The distribution pattern of fatty acids in fish lipid was separated and identified by Thin Layer Chromatography (TLC). Fish lipid under investigation contained myristic acid (C14: 0), palmitic acid (C16: 0), stearic acid (C18:0), oleic acid (C18: 1), lionoleic acid (C18: 2), lionolenic acid (C18: 3), arachidic acid (C20: 0) and behenic acid (C22: 0). These results revealed that the lipid is pharmacologically active owing to the fact that it is necessary for proper functioning of many metabolic processes. Fatty acids xv composition and chain length of fatty acids in this fish lipid were determined by Gas Liquid Chromatography (GLC). In GLC examination, the mixture of fatty acid methyl esters derived from fish lipid were separated on polar column having stationary phase diethyleneglycosuccinate (DEGS). The identities of the individual fatty acid were achieved by co-chromatography with standard reference compounds. It was established from the GLC examination, the mixture of fatty acid methyl esters derived from fish lipid that the mixture contained fatty acids consisting of carbon C14 to C22. The percentage of each fatty acid methyl ester derived from fish lipid was provided by printed out record of the chromatogram of GLC. The percentages of composition of each fatty acid methyl ester in the fish lipid derived from the chromatogram were 6.33% myristic acid; 24.23% palmitic acid; 8.42% stearic acid; 30.29% oleic acid; 7.35% lionoleic acid; 5.46% lionolenic acid; 2.47% arachidic acid; 4.25% behenic acid and 11.13% unknown acid. Analysis of this fish lipid for fatty acids indicates that the lipid contained 7.35% linoleic acid (ω-6 fatty acid) and 5.46% linolenic acid (ω -3 fatty acid). These fatty acids are an important part of the structural component of cell membranes and are necessary for the formation of eicosanoids which assist in blood pressure regulation, blood clot formation, maintenance of blood lipid levels and assist in the body immune response. The fish lipid contained about 43.1 oleic acid (monounsaturated fatty acids) can able to promote the high level of HDL cholesterol and hence decreasing the risk of heart diseases in human body. The concentrations of saturated fatty acids in this fish lipid were 42.43% of total lipids; monounsaturated fatty acids 43.1% and polyunsaturated fatty acids 14.43%. The fish lipid is suitable for edible purpose as it contained both ω-3 and ω-6 fatty acid especially linoleic and alpha-linolenic acids. The effect of feeding Fish Protein Concentrate (FPC) at different protein levels with formulated cereal have been performed to identified the nutritional significance of fish P. gonionotus by determining the gain in body weights per one gram of food intake, Protein Efficiency Ratio (PER) and Calorie Efficiency Ratio (CER) values in twelve male young male albino rats for 32 consecutive days. For this purpose, five experimental diets were prepared at different protein levels (5% to 25%) with supplied formulated cereal where the control diet was prepared with supplied xvi formulated cereal only. Each mean gain in body weight per one gram of food intake, PER and CER were increased with increasing protein levels supplemented with formulated cereal and showed maximum value of 0.534g, 2.53 and 13.02 respectively at 15% protein level. When protein levels were further increased through FPC, fall in gain in body weights per one gram of food, PER and CER have been observed in diet E (0.457g, 2.11 and 11.15 respectively) and diet-F (0.432g, 1.02 and 10.53 respectively). Locomotive behaviour, central nervous system, excitation, weakness, reflexes, salivation, urination, diarrhoea, etc. of all albino rats are found normal during the experimental period. After consuming the diets containing FPC at different protein levels produces no observable changes in blood constituents like total RBC count (106 /µl), hemoglobin (g/dl), erythrocyte sedimentation rate (ESR)(mm), total WBC Count (103 /µl), differential count of WBC (neutrophil, lymphocytes, monocytes, eosoniphils) with that of control group and the blood cholesterol (mg/dl) levels of the treated rats were increased gradually than control group. Histopathological examination of the heart, liver, lung, kidney and spleen of all treated rats were found normal and no morphological change were found in their microscopic view with respect to the control group. In Brine Shrimp Lethality bioassay, the chloroform-methanol extract of this fish lipid showed negative results indicating that the fish lipid was biologically inactive. From this experiment, it is revealed that the fish lipid has no toxicity against any living organisms