Changes in the Quality of Refined Fish Oil in an Accelerated Storage Study

ABSTRACT

The aim of this study was to prepare the refined oil derived from Sardinella longiceps by a step-wise procedure of degumming, bleaching, and deodorization. The refined sardine oil showed greater susceptibility toward oxidation than the crude oil, but the addition of ethyl acetate fractions of the red seaweeds Hypnea musciformis, Kappaphycus alvarezii, and Jania rubens with great antioxidant potential significantly increased the oxidative stability of the refined oil. The refined oil supplemented with the ethyl acetate fraction of these seaweeds indicated more noteworthy oxidative stability indices (≥ 0. 51 h) than α-tocopherol. The induction time was greater for refined oil added with H. musciformis (1.26 h) than butylated hydroxytoluene (1.04 h) and α-tocopherol (0.4 h). No traces of aromatic (δ 6.7–7.5 ppm), hydroperoxides, and aldehydes (δ 9–10 ppm) in the ¹H-NMR spectra of the refined oil supplemented with seaweed extracts at the baseline and after the accelerated storage study demonstrated that the seaweed extracts were able to prevent the formation of secondary oxidation products in the unsaturated system during storage. This study demonstrated the potential of seaweeds as natural alternatives to the synthetic antioxidants to prevent the rancidity of the refined fish for use in food and pharmaceutical industries.     

Dietary bovine lactoferrin induces changes in immunity level and disease resistance in Asian catfish Clarias batrachus

The effects of including bovine lactoferrin (Lf) in the diet of the Asian catfish (Clarias batrachus) on specific and non-specific immunity as well as disease resistance were investigated. The catfish were fed four different diets for 2 weeks: a commercial diet as control and the same diet supplemented with 50, 100 and 200mg bovine Lf/kg feed. After 1 and 2 weeks, serum bacterial agglutination titre against Aeromonas hydrophila as a measure of specific immunity; natural serum haemolysin titre, lysozyme activity and oxidative radical production by neutrophils as a measure of non-specific immunity as well as disease resistance against A. hydrophila challenge to vaccinated and non-vaccinated animals were evaluated. The results showed that Lf supplements, particularly at 100mg level, significantly (P<0.05) enhanced serum lysozyme level, oxidative radical production and level of protection against A. hydrophila challenge in non-vaccinated animals irrespective of length of exposure. The specific immunity was not influenced by Lf feeding as evidenced from the bacterial agglutination titre and level of protection in vaccinated animals. As Lf feeding at 100mg/kg for 1 week is able to enhance the non-specific immunity and disease resistance of catfish efficiently, these results support the possible use of Lf as an immunostimulant for farmed catfish.     

Zaluzanin D: a fungistatic sesquiterpene from Vernonia arborea

Zaluzanin D, a sesquiterpene lactone has been isolated from the aerial parts of Vernonia arborea as a major constituent (0.04%). Antifungal activity of zaluzanin D has been studied against six plant-pathogenic fungi.     

Eicosapentaenoic acid enrichment from sardine oil by argentation chromatography

Eicosapentaenoic acid (EPA) derived from chemically hydrolyzed sardine oil was concentrated by urea fractionation using methanol at different temperatures (2, 4, and 6 degrees C) and urea/fatty acid ratios (2:1, 3:1, and 4:1 w/w) and purified by argentation neutral alumina column chromatography. The individual fatty acids were determined as fatty acid methyl esters (FAME) by gas-liquid chromatography and gas chromatography-mass spectroscopy as FAME and N-acyl pyrrolidides. In the mass fragmentation pattern of FAME, the base peak was assigned to be the 1-methoxyethenol moiety (m/z = 74) obtained by McLafferty rearrangement. Formation of the cyclic tropylium ion (m/z = 91) in fatty acids with four or more double bonds was apparent in FAME-PUFAs. The base peak of N-acyl pyrrolidides was the McLafferty rearrangement ion, 1-(pyrrolidin-1-yl)ethenol (m/z = 113). The highest concentration of EPA (47.78%) was obtained at the crystallization temperature of 4 degrees C with a urea/fatty acid ratio of 4:1 (w/w) with 93.74% yield. After complexation of saturated and less unsaturated fatty acids by urea complexation, argentation chromatography resulted in an EPA of high purity (99.6%) with an overall recovery of 54.09% using 50% diethyl ether/n-hexane as eluting solvent. The peroxide (POV) and thiobarbituric acid (TBS) values were found to be highest (4.0 mequiv of O2/kg and 5.2 mg of malondialdehyde/kg, respectively) during urea fractionation at the higher crystallization temperature (6 degrees C) and higher urea/fatty acid ratio (4:1). Keywords: Sardine oil; eicosapentaenoic acid (EPA); fatty acid methyl esters (FAME); urea fractionation; argentation column chromatography.     

Dietary levamisole modulates the immune response and disease resistance of Asian catfish Clarias batrachus (Linnaeus)

In order to determine the immunomodulatory effect of dietary levamisole in Asian catfish (Clarias batrachus), fish were fed four different diets for 10 days: a formulated diet as control and the same diet supplemented with 50, 150 or 450 mg levamisole kg^?1 feed. The serum bacterial agglutination titre against Aeromonas hydrophila as a measure of specific immunity, serum haemagglutination titre, natural haemolytic complement activity (ACH₅₀), myeloperoxidase and lysozyme activities, total protein level and oxidative radical production by neutrophils as a measure of non‐specific immunity as well as disease resistance against A. hydrophila challenge to separate vaccinated and non‐vaccinated groups were evaluated at 0, 1, 2 and 3 weeks after last administration of levamisole. Levamisole supplement at the lowest level (50 mg kg^?1) significantly enhanced oxidative radical production and serum myeloperoxidase (MPO) content immediately after 10 days of feeding, which reached peak values after 3 and 2 weeks of feeding respectively. Haemolytic complement and haemagglutination titre were significantly enhanced after 3 and 1 weeks respectively. Haemolytic complement activity and MPO activities were significantly raised to 150 mg kg^?1 after 3 and 2 weeks, respectively. At the highest level of levamisole feeding (450 mg kg^?1) significant decreases in superoxide production and complement activity were measured immediately after levamisole feeding, which returned to the normal level after 1 week post‐ feeding. Fish were challenged with a virulent strain of A. hydrophila at 0, 1, 2 and 3 weeks after levamisole feeding, and the cumulative per cent survival was recorded over 10 days. Feeding levamisole at 50, 150 or 450 mg kg^?1 increased per cent survival in vaccinated fish immediately after levamisole feeding, and survival was significantly higher at 450 mg kg^?1. There was no difference in mortality patterns in non‐vaccinated fish. The results support the use of levamisole at 50 mg kg^?1 feed for 10 days as an immunostimulant in Asian catfish farming.     

Process Optimization for the Development of Nutritionally Enhanced Nuggets using Ficus geniculata: A Nutritional Approach

Plant Foods for Human Nutrition - Ficus geniculata (FG) is one of the underutilized fig species in India and throughout the world. However, the different parts of the plant have numerous...     

Synthesis and quantitative structure-activity relationships of oxanilates as chemical hybridizing agents for wheat (Triticum aestivum L.)

Chemical hybridizing agents (CHAs) can facilitate two-line breeding in heterosis programs of crops. Twenty-seven oxanilates having different aromatic substitutions were synthesized and screened as CHAs on two genotypes of wheat, PBW 343 and HD 2733, during two Rabi (winter) seasons, 2000-01 and 2001-02. The oxanilates prepared by thermal condensation of anilines with diethyl oxalate or by acylation with ethoxycarbonyl methanoyl chloride were sprayed at 1000 and 1500 ppm at the premeiotic stage of wheat, when the length of the emerging spike of the first node was 7-8 mm. Pollen sterility and spikelet sterility were measured in each treatment. Ethyl oxanilates 5, 6, and 25,containing 4-F, 4-Br, and 4-CF(3) aromatic substituents, respectively, induced greater than 98% spikelet sterility, the desired level, at 1500 ppm. Quantitative structure-activity relationship analysis revealed a direct relationship between F(p) and molecular mass but an inverse relationship between MR, E(S), and R in influencing the bioactivity. Several F(1) hybrids were developed using 5, and at least one showed heterosis.     

Fungal degradation of chlorpyrifos by <Emphasis Type="Italic">Acremonium</Emphasis> sp. strain (GFRC-1) isolated from a laboratory-enriched red agricultural soil

The organophosphorus insecticide, chlorpyrifos, has been widely applied in agriculture; in veterinary, against household pests; and in subterranean termite control. Due to its slow rate of degradation in soil, it can persist for extended periods in soil with a significant threat to environment and public health. The mixed and pure fungi were isolated from three soils by enrichment technique. The enriched mixed fungal cultures were capable of biodegrading chlorpyrifos (300 mg L⁻¹) when cultivated in Czapek Dox medium. The identified pure fungal strain, Acremonium sp., utilized chlorpyrifos as a source of carbon and nitrogen. The highest chlorpyrifos degradation (83.9%) by Acremonium sp. strain GFRC-1 was found when cultivated in the nutrient medium with full nutrients. Desdiethyl chlorpyrifos was detected as a major biodegradation product of chlorpyrifos. The isolated fungal strain will be used for developing bioremediation strategy for chlorpyrifos-polluted soils.     

The Alleviating Effect of Elevated CO2 on Heat Stress Susceptibility of Two Wheat (Triticum aestivum L.) Cultivars

This study analysed the alleviating effect of elevated CO₂ on stress‐induced decreases in photosynthesis and changes in carbohydrate metabolism in two wheat cultivars (Triticum aestivum L.) of different origin. The plants were grown in ambient (400 μl l^?1) and elevated (800 μl l^?1) CO₂ with a day/night temperature of 15/10 °C. At the growth stages of tillering, booting and anthesis, the plants were subjected to heat stress of 40 °C for three continuous days. Photosynthetic parameters, maximum quantum efficiency of photosystem II (PSII) photochemistry (F_v/F_m) and contents of pigments and carbohydrates in leaves were analysed before and during the stress treatments as well as after 1 day of recovery. Heat stress reduced P_N and F_v/F_m in both wheat cultivars, but plants grown in elevated CO₂ maintained higher P_N and F_v/F_m in comparison with plants grown in ambient CO₂. Heat stress reduced leaf chlorophyll contents and increased leaf sucrose contents in both cultivars grown at ambient and elevated CO₂. The content of hexoses in the leaves increased mainly in the tolerant cultivar in response to the combination of elevated CO₂ and heat stress. The results show that heat stress tolerance in wheat is related to cultivar origin, the phenological stage of the plants and can be alleviated by elevated CO₂. This confirms the complex interrelation between environmental factors and genotypic traits that influence crop performance under various climatic stresses.