Fish Liver Discards as a Source of Long chain Omega-3 Polyunsaturated Fatty Acids

The intake of omega-3 polyunsaturated fatty acids (PUFA) of the average consumer is generally low and products like fish oils high in omega-3 PUFA have become a popular dietary supplement. There is a need for more sources of omega-3 PUFA to cover the increasing demand. This study investigated whether livers from different lean fish species could be a potential new source of oils rich in omega-3 PUFA. The seasonal variation in lipid content, fatty acid composition, peroxide value and free fatty acid content of livers from cod, hake, ling, coalfish and monkfish was determined and the effect of storage conditions on the fishing vessel (ice vs frozen) was studied. Generally, the lipid content and composition of the livers from the five fish species varied similarly during the two years of sampling period with significantly lower values in spring (March, April) and higher values in fall (November, October). Storage conditions were found to have no significant effect on the quality and oil composition. Monkfish livers were less suitable for production of omega-3 oil due to their lower lipid and EPA content and higher FFA levels. Coalfish had higher fluctuations in oil composition during sampling period, which potentially makes a standardised quality difficult to obtain. Cod, hake and ling were the most suitable species for fish liver oil production.

Histopathological changes in the internal organs of female striped gourami (Trichogaster fasciata) exposed to sub-lethal concentrations of salt water

The present study was conducted to evaluate the effects of climate induced salinity on histoarchitecture of liver, kidney and ovary tissue of female striped gourami (Trichogaster fasciata) exposed tothree sub-lethal concentrations (3, 6 and 9 ppt) of crude salt along with a control group (0 ppt) for a periodof 30 days. The 96-h LC50 value of crude salt for striped gourami was previously estimated as 11.107 ppt. Toconduct the experiment 12 plastic tanks each having 70L water holding capacity were used for the fourtreatments with three replications for each. Water exchange was done on every 10th day and crude salt wasused to maintain desired salinity. Several histopathological changes were observed in fish liver, kidney andovary exposed to different concentrations of salinity. Increasing necrosis, hemorrhage, hepatic rupture,melano-macrophage cells, degenerated cell and vacuums in the liver tissue were found in salt water treatedgroups. Similarly, a number of changes such as, vacuole, cellular degeneration, hemorrhage, disintegratedglomeruli, destructed renal tubule and extensive vacuolein were observed in the kidney tissue of salt watertreated groups. Degenerated oocyte, inter-follicular space, disrupted oocytes, etc. were observed in ovarywith increasing concentration of salinity and time of exposures. Physiological and metabolic dysfunctionsmight have happened to female stripped gourami due to changes in vital internal organs like liver, kidney andovary. Therefore, the present research further suggested that climate induced salinity intrusion is capable ofstressing freshwater fishes resulting in deformities of liver, kidney and ovary.

Catalase Activity in Response to Metals in Freshwater Fish Catla catla

Catalase activity in response to binary metal mixture of Zn + Ni was studied in gills, hepatic, renal and cardiac tissues of Catla catla. A total of 30 fish fingerlings were kept in two glass aquaria (15 in controlled condition and 15 in metal mixture containing aquarium) for the period of two weeks. After the completion of the trial period, fish were dissected for different organ collection. The extracted organs were homogenized in phosphate buffer (50 mM; pH 7.0). The activity of catalase was determined by absorption at 240 nm by using the standard methods. The inferences showed higher catalase activity in liver (223.33 ±1 UmL-1), kidney (163.33 ± 0.7 UmL-1), gills (123.33 ±0.9 UmL-1) and cardiac (120 ±3 UmL-1) tissues of Zn + Ni treated fish in comparison to controlled fish liver (116.66 ±2 UmL-1), kidney (101.66 ±1 UmL-1), gills (96.66 ±0.66 UmL-1) and cardiac tissues (70 ±0.33 UmL-1) in this study. Statistically, significant differences at p ≤ 0.05 was observed for catalase activity between Zn + Ni stressed and control fish groups. While, in different organs of both group of fishes the catalase activity order was observed as hepatic > renal > gills > heart. Findings of this study would be helpful in monitoring aquatic ecosystems using fish antioxidant system which acts as a bio-indicator of metal contamination.

Vitamin and mineral analysis of fish liver oil, some locally available spices and vegetables

High Performance Liquid Chromatography (HPLC) was used to determine the vitamin and mineral contents of some locally sourced ingredients such as fish liver oil, Adansonia digitata, Telfaria occidentalis, Celosia spp, Amaranthus cruentas leaves, Xylopia aetiopica, capsicum frutenscen, Saccharomyces cerevicae, rice bran, palm oil and colostrums. The results indicated that fish liver oil was the most potent source of vitamins A, D, E and B12 represented by 9x10 6 iu/100g, 48000icu/100g, 30mg/100g, and 40.5mg/100g, respectively. The B-Complex vitamins were present among the spices and vegetables analyzed. Saccharomyces cerevicae was observed to a potent source of thiamin (9.4mg /100g) and niacin (41.8 mg / 100g). Capsicum spp and Telfaria occidentalis had ample amounts of riboflavin, thiamin and niacin. Rice bran had the highest amount of pyridoxine, 28.6mg/100g, while panthothenate was present more in the milk (8.2mg/100g) than other materials analysed. The mineral composition of the materials analysed showed that they have fairly uniform potency. Amaranthus cruentas was found to contain more mineral with 3.0, 1.4, 5.13, 1.10, 5.04 and 1.09% for copper (cu), Zinc (Zn), potassium (K), Sodium (Na), Calcium (ca), and magnesium (mg), respectively. The results of the analysis indicated that vitamin and mineral potencies of these ingredients can be harnessed for the production of vitamin and mineral premix for animal feed formulation