A new assembly and technique for testing insecticides

A new design of insecticide testing assembly has been devised that is highly versatile in testing the efficacy, potency and interaction of insecticides and other test chemicals. The merits of the assembly and technique have been explained.     

Utilization of fermented silkworm pupae silage in feed for carps

Fermented silkworm pupae (SWP) silage or untreated fresh SWP pastes were incorporated in carp feed formulations replacing fishmeal. The feed formulations were isonitrogenous (30.2-30.9% protein) and isocaloric (ME = 2905-2935 kcal/kg). Feeding under a polyculture system consisting of 30% each of catla (Catla catla), mrigal (Cirrhinus mrigala) and rohu (Labeo rohita) with 10% silver carps (Hypophthalmychthys molitrix) was carried out in ponds to evaluate the nutritive quality of SWP silage. Survival rate, feed conversion ratio and specific growth rate, respectively, were 84.2%, 2.10 and 2.39 for fermented SWP silage, 65.8%, 2.98 and 2.26 for untreated SWP and 67.5%, 3.16 and 2.20 for fishmeal indicating clearly that the fermented SWP silage was nutritionally superior to untreated SWP or fishmeal. The dietary influence on the proximate composition of whole fish was marginal.     

鳞翅目昆虫人工饲料的研究现状

鳞翅目昆虫为昆虫纲第二大目昆虫,其中大多数为农业害虫,以及可作为资源开发利用的资源昆虫。对鳞翅目人工饲料的研究是对其进行科学研究与资源利用的基础。本文阐述了目前鳞翅目昆虫人工饲料研究的现况,并提出了研究中存在的若干问题。     

The artificial contamination of poultry feed with Salmonella and its infectivity for young chickens

Poultry food was successfully contaminated with Salmonella kedougou by a two-stage mixing process in which broth containing the organisms was mixed initially into desiccated coconut before mixing with the food. Food contaminated by this process was capable of infecting chickens fed the food for 3 weeks from the day of purchase.     

The design and performance of an atomizing nozzle for use with a spraying tower for testing liquid insecticides

A nozzle, P.I.L. No. AN₂, has been designed for, and used successfully in, the biological assay of insecticides in a heavy oil solution. This new nozzle is easier to adjust and gave a standard deviation of deposit one-seventh of that given by the nozzle described by Potter (1941).     

Genotoxicity testing of six insecticides in two crosses of the Drosophila wing spot test

Among the great variety of genotoxicity assays available, the wing spot test in Drosophila melanogaster has some characteristics that make it very suited for the screening of genotoxic activity, i.e., it is an easy and inexpensive assay using a eukaryotic organism in vivo. One of the most interesting characteristics of the assay is its capacity to detect genotoxic activity of promutagens without the necessity of an exogenous metabolic activation system. In this paper we present results obtained with a recently developed high bioactivation cross of the wing spot test (NORR cross). The positive results obtained with the five well-known procarcinogens 7, 12-dimethylbenz[a]anthracene, N-nitrosopyrrolidine, p-dimethylaminoazobenzene, diethylnitrosamine and urethane clearly show that the NORR strains are similar to the other high bioactivation strains previously described, but they lack their methodological disadvantages. We have tested six insecticides, which are characterised by having contradictory results in other genotoxicity tests, using both the standard and the high bioactivation (NORR) cross. The six insecticides analysed are the pyrethroid allethrin, the methylenedioxyphenolic compound piperonyl butoxide, the chlorinated hydrocarbons dieldrin and endrin, and the organophosphates dimethoate and malathion. We obtained negative results for all six compounds. Our results show the suitability of the wing spot test for the evaluation of compounds at the first level of genotoxicity testing.     

Utilization of glycosyltransferases for the synthesis of a densely packed hyperbranched polysaccharide brush coating as artificial glycocalyx

Densely packed polysaccharide brushes consisting of α-D-glucose residues were grafted from modified silicon substrates. Potato phosphorylase was herein used to grow linear polysaccharide chains from silicon tethered maltoheptaose oligosaccharides using glucose-1-phosphate as donor substrate. The combined use of potato phosphorylase and Deinococcusgeothermalis branching enzyme resulted in a hyperbranched brush coating as the latter one redistributes short oligosaccharides from the α(1-4)-linked position to the α (1-6)-linked position in the polysaccharide brush. The obtained grafting density of the brushes was estimated on 1.89 nm(-2) while the thickness was measured with ellipsometric techniques and determined to be between 12.2 and 20.2 nm.     

A spinning-disk sprayer for applying residual insecticides

The apparatus consists essentially of a spinning disk which throws off liquid, applied to its centre, in the form of small droplets. These are of the same order of size (about 0.1–0.4 mm. diameter) as those produced by knapsack sprayers, but they are more uniform and consistent.
The sprayer can be used to coat various surfaces, up to 1 ft. square, with deposits of insecticides in oil solution or in aqueous suspensions or emulsions. The deposits can be controlled and estimated with a fair degree of precision.
Some rough samples of the spray clouds produced by a knapsack sprayer are recorded.     

Utilization of shrimp industry waste in the formulation of tilapia (Oreochromis niloticus Linnaeus) feed

A rapid expansion of fisheries is demanding an adequate supply of efficient, nutritious and inexpensive fish feed, because feed contributes highly to the cost of fish production. Shrimp head, a waste product from the shrimp export industry qualifies as an economical, abundant and good quality protein source for fish feeds. In the present work, shrimp head silage powder, which contained approximately 40% protein, was used as a substitute for fish flour. Four feeds, in the form of pellets, were prepared by substituting shrimp head silage for fish flour at 0%, 33.3%, 66.6% and 100% dietary levels. Other ingredients such as corn, soy, bovine blood, cassava and corn cob flours, soy oil, vitamin premix, salt, and other components also were used in the formulation. A commercial fish feed was used as the control. The proximate composition of these feeds did not differ significantly at p>0.05, except for the protein content of the control feed, which was about 30.6% versus 35.4-36.9% protein in the other diets. No significant differences (p>0.05 level) in weight and length of juveniles fed with the different feeds during a period of 60 days were observed. In all cases, an excellent correlation (0.9950-0.9996) between weight and length of juveniles was observed. No significant difference in growth of juveniles fed on R1, R2, R3, or R4, or the control feed, was observed. Similarly, the proximate analyses of the flesh of juveniles did not present significant differences (p>0.05). The result of the study indicates that the shrimp head silage could replace fish flour as an ingredient in tilapia feed with economic advantages and without sacrificing the quality of the feed.     

Prediction of amino acid profiles in feed ingredients:: Genetic algorithm calibration of artificial neural networks

Linear regression (LR) has been used to predict the amino acid (AA) profiles of feed ingredients, given proximate analysis (PA) input. Artificial neural networks (ANN) have also been trained to predict AA levels, generally with better results. Past projects have indicated that ANN more effectively identified the complex relationship between nutrients and feed ingredients than did LR. It was shown that the maximum R² value, a measurement of the amount of variability explained by the model, was highest when a general regression neural network (GRNN) with iterative calibration (GRNNIT) was used to train the ANN. This was in comparison to LR, Ward backpropagation (WBP) or 3-layer backpropagation (3BP) architectures. The current study investigated the potential of a new, advanced method of calibration using the genetic algorithm (GA) to optimize GRNN smoothing values. Calibration of an ANN allows the neural network to generalize well and therefore provide good results on new data. A GRNN architecture (NeuroShell 2^® Software) with GA calibration (GRNNGA) was used to train an ANN to predict AA levels in maize, soya bean meal (SBM), meat and bone meal, fish meal and wheat, based on proximate analysis input. Within the GRNNGA architecture, ANN were trained with either an Euclidean or City Block distance metric and a (0,1), (−1,1), (logistic) or (tanh) input scale. Predictive performance was judged on the basis of the maximum R² value. In general, maximum R² values were higher when the GA calibration was used in comparison to LR. For example, the highest methionine (MET) R² value for SBM was 0.54 (LR), 0.81 (3BP), 0.87 (WBP), 0.92 (GRNNIT) and 0.98 (GRNNGA). Genetic algorithm calibration of GRNN architecture led to further improvements in ANN performance for AA level predictions in most of the cases studied. Exceptions were the TSAA level in SBM (0.94 with GRNNIT vs. 0.90 with GRNNGA) and the TRY level in maize (0.88 with GRNNIT vs. 0.61 with GRNNGA).     

Fermented liquid feed for pigs

Since the announcement of the ban on the use of antibiotics as antimicrobial growth promoters in the feed of pigs in 2006 the investigation towards alternative feed additives has augmented considerably. Although fermented liquid feed is not an additive, but a feeding strategy, the experimental work examining its possible advantages also saw a rise. The use of fermented liquid feed (FLF) has two main advantages, namely that the simultaneous provision of feed and water may result in an alleviation of the transition from the sow milk to solid feed and may also reduce the time spent to find both sources of nutrients, and secondly, that offering FLF with a low pH may strengthen the potential of the stomach as a first line of defence against possible pathogenic infections. Because of these two advantages, FLF is often stated as an ideal feed for weaned piglets. The results obtained so far are rather variable, but in general they show a better body weight gain and worse feed/gain ratio for the piglets. However, for growing-finishing pigs on average a better feed/gain ratio is found compared to pigs fed dry feed. This better performance is mostly associated with less harmful microbiota and better gut morphology. This review provides an overview of the current knowledge of FLF for pigs,dealing with the FLF itself as well as its effect on the gastrointestinal tract and animal performance.     

Metabolism of organophosphorus insecticides

Summary The metabolism of ³²P-Malathion in Rhizobium leguminosarum and Rhizobium trifolii has been investigated. In addition to inorganic phosphates and/or thiophosphates, 5 hydrolytic metabolites could be identified. The carboxylic acid derivatives constituted the major portion (35–40% of the total metabolites output) suggesting the presence of powerful carboxyesterases in both Rhizobium spp. Malaoxon could not be detected in the media of both organisms.