Evaluation of the dietary essentiality of vitamins for Penaeus monodon

The effect of deletion of individual water-soluble (thiamin, riboflavin, pyridoxine, cyanocobalamin, pantothenic acid, folic acid, niacin, biotin, choline, inositol and ascorbic acid) and fat-soluble vitamins (vitamins A, D, E and K) in semipurified diets on growth and survival of juvenile shrimp, Penaeus monodon , was studied in the laboratory for 8 weeks. Diets lacking riboflavin and vitamin K did not affect growth and survival of shrimp. However, deletion of inositol and choline in the diet resulted in poor growth. Maximum growth was observed in the control diet (C1) supplemented with all vitamins. Diets deficient in ascorbic acid, biotin, folic acid, niacin, thiamin and α-tocopherol resulted in poor appetite and poorer feed conversion efficiency. All treatments except the control (C1) resulted in histopathological changes in the digestive gland cells. Detachment or destruction of the epithelial cells was observed in all treatments lacking individual vitamins but more severely in the treatment without a vitamin supplement, followed by inositol, choline and ascorbic acid deficient diets.     

Effects of rapeseed oil replacement in fish feed on lipid composition and self‐selection by rainbow trout (Oncorhynchus mykiss)

Increased use of plant oils with different origins and quality in fish feed needs to be approached from a food safety and fish welfare point of view. Plant oils contain a number of bioactive minor lipid compounds that may affect the fish’s metabolism and taste perception. This study focuses on the effect of replacing fish oil (FO) with different levels of cold‐pressed rapeseed oil (RO) on the lipid composition in muscle and liver as well as on the preference by the fish. Rainbow trout (Oncorhynchus mykiss) were fed diets with a FO : RO ratio of 100 : 0, 75 : 25, 50 : 50 and 25 : 75 until twofold weight increase. In self‐selecting feed trials of single rainbow trout, fish preferred the diet composed of only FO compared with the diets with RO but did not discriminate between different levels of RO. Plant sterols and their metabolites were found in liver of the fish fed RO diets, suggesting an effect on the sterol metabolism different from fish fed a 100% FO diet. The largest effects were seen in the fatty acid composition of the edible tissue of the fish with a decrease in 22:6n‐3 and 20:5n‐3 and an increase in 18:2n‐6 and 18:1n‐9.     

Optimum timing of insecticide applications against diamondback moth Plutella xylostella in cole crops using threshold catches in sex pheromone traps

Field trials were conducted in cabbage (Brassica oleracea var capitata), cauliflower (B oleracea var botrytis) and knol khol (B oleracea gongylodes) crops at two different locations in Karnataka State (India) to optimize the timing of insecticide applications to control the diamondback moth, Plutella xylostella, using sex pheromone traps. Our results indicate that applications of cartap hydrochloride as insecticide during a 12–24 h period after the pheromone traps had caught on average 8, 12 and 16 males per trap per night in cabbage, cauliflower and knol khol, respectively, were significantly more effective than regular insecticide sprays at 7, 9, 12 or 15 days after transplantation. This was demonstrated by estimation of the mean number of eggs and larvae per plant, the percentage of holes produced, as well as the marketable yield of the three crops at each location. A good correlation between the immature stages, infestation level, the estimated crop yield and the number of moths caught in pheromone traps was also found, indicating the usefulness of pheromone‐based monitoring traps to predict population densities of the pest. © 2001 Society of Chemical Industry     

EFFECT OF NANOSCALE ZINC OXIDE PARTICLES ON THE GERMINATION,GROWTH AND YIELD OF PEANUT

An investigation was initiated to examine the effects of nanoscale zinc oxide particles on plant growth and development. In view of the widespread cultivation of peanut in India and in other parts of the globe and in view of the potential influence of zinc on its growth, this plant was chosen as the model system. Peanut seeds were separately treated with different concentrations of nanoscale zinc oxide (ZnO) and chelated bulk zinc sulfate (ZnSO₄) suspensions (a common zinc supplement), respectively and the effect this treatment had on seed germination, seedling vigor, plant growth, flowering, chlorophyll content, pod yield and root growth were studied. Treatment of nanoscale ZnO (25 nm mean particle size) at 1000 ppm concentration promoted both seed germination and seedling vigor and in turn showed early establishment in soil manifested by early flowering and higher leaf chlorophyll content. These particles proved effective in increasing stem and root growth. Pod yield per plant was 34% higher compared to chelated bulk ZnSO₄. Consequently, a field experiment was conducted during Rabi seasons of 2008–2009 and 2009–2010 with the foliar application of nanoscale ZnO particles at 15 times lower dose compared to the chelated ZnSO₄ recommended and we recorded 29.5% and 26.3% higher pod yield, respectively, compared to chelated ZnSO₄. The inhibitory effect with higher nanoparticle concentration (2000 ppm) reveals the need for judicious usage of these particles in such applications. This is the first report on the effect of nanoscale particles on peanut growth and yield.     

Identification of SSR markers which could differentiate blast disease resistance accessions in finger millet (<Emphasis Type="Italic">Eleusine coracana</Emphasis> (L.) Gaertn.)

Microsatellites also known as SSR are the class of repetitive DNA sequences present throughout the genome of all eukaryotic organisms. The present study identified SSRs using biotinylated beads capture method. Ten sets of primers were designed based on sequences having at least (CT)10 repeats. A total of 27 accessions having a mix of both African (resistant) and Indian origin (resistant and susceptible) were assessed using 30 microsatellite markers. Amplification products were obtained for all 30 primers studied; 25 out of these primers were found to be polymorphic with 13 primers showing two alleles per locus. The current study identified markers which could differentiate between resistant and susceptible accessions and also segregate accessions based on geographical region. These informative SSR markers can be used in finger millet genetic improvement projects.     

Rehabilitation of saline soil with biogas digestate,humic acid,calcium humate and their amalgamations

ABSTRACT

Amelioration of saline soil is a requisite in order to increase crop productivity. A soil incubation study was performed for 60 days using digestate, humic acid, calcium humate and their combinations to investigate the influence on physical, chemical, microbial and enzyme activities of saline soil. Overall, digestate combined with calcium humate followed by humic acid treatments have shown their potency in decreasing the soil pH, electrical conductivity (EC), and sodium ion (Na⁺) concentration, and increase in potassium ion (K ⁺), calcium ion (Ca ²⁺), magnesium ion (Mg ²⁺), mean weight diameter (MWD), soil enzyme activities, microbial biomass carbon (MBC), MBC: microbial biomass nitrogen (MBN) and soil respiration than control. The digestate, humic acid individually and their amalgamation evidenced greater MBN among all the treatments. The digestate alone efficiently improved the soil properties than humic acid and calcium humate individual groups except for the MWD where it is pronounced more in the latter groups. The greater metabolic quotient (qCO₂) was observed in control than organic matter amended treatments indicating the stress conditions. The increase in water-extractable organic matter (WEOM) with minimal aromaticity (specific ultraviolet absorbance at 254 nm-Suva ₂₅₄) in integrated amendments comprising groups, laid the ground reason to improve the properties of saline soil. Therefore, this study concludes that the fusion of fresh and humified substrates could facilitate reclamation.