Effects of supplementing methionine hydroxy analogue in soybean meal and distiller's dried grain-based diets on the performance and nutrient retention of rainbow trout [Oncorhynchus mykiss (Walbaum)]

Two experiments were conducted to evaluate the effects of supplementing methionine hydroxy analogue (MHA) on the performance, body composition, and nutrition retention of rainbow trout. In experiment 1, a 2×4 factorial arrangement with two MHA supplemental levels (with and without) and four fish meal replacement levels (25%, 50%, 75%, and 100%, replaced with soybean meal (SBM) and wheat gluten) was used. A fish meal diet was included as a control. Results showed that fish meal replacement levels had significant effects on fish weight gain (WG), feed conversion ratio (FCR), body moisture, crude protein, crude fat, and ash (P<0.05). In experiment 2, a fish meal reference diet and seven other diets were made using SBM and distiller's dried grain with solubles supplemented with 0, 0, 0.55, 1.1, 1.65, 2.2, and 2.75 g MHA kg^?1 diet to replace 50% of fish meal. WG, FCR, and apparent retention of crude protein and phosphorus were significantly improved in rainbow trout fed the diet containing 1.65 g MHA kg^?1 diet compared with fish fed an equivalent diet without MHA.     

Cold plasma: a potential new method to manage postharvest diseases caused by fungal plant pathogens

Development of alternative, chemical‐free approaches for control of postharvest fungi on a commercial scale has become a challenge for plant pathologists in recent years. Although there are several established techniques such as heat that are used as postharvest treatments, they often have disadvantages, including alteration of food quality due to physiological responses to the treatment, or environmental pollution. A promising new postharvest treatment is cold plasma, which is a gas‐derived mix of atoms, excited molecules and charged particles. Cold plasma has no known adverse effects on fresh produce or the environment. It is an established technology in the medical field and has been demonstrated to successfully control bacterial pathogens that cause food safety issues. This review focuses on the potential of cold plasma technology for postharvest disease control, especially those caused by fungi. An overview of plasma generation systems is provided, and in vivo and in vitro research is reviewed to consider benefits, limitations and research gaps in the context of cold plasma as a potential method for controlling postharvest fungal pathogens. Finally, recommendations are provided for the application of this technology in commercial facilities.     

Microbial,chemical and physical changes during composting of a eucalyptus (Eucalyptus calophylla and Eucalyptus diversicolor) bark mix

Summary Physical, chemical, and population changes among microorganisms in a eucalyptus bark mix were examined during composting. The microbial succession was studied in detail by dilution plating. The CO₂ evolution corresponded to high microbial numbers. The pH increased rapidly, from 4 to 7.5, before stabilizing at approximately 6.5. Composting increased the availability of most nutrients. Initially, bacteria and filamentous fungi appeared to be the main decomposing organisms. With time, however, yeasts and actinomycetes increased in numbers. The numbers of spore-forming bacteria (Bacillus spp.) and pseudomonads also increased with time. The compost was initially phytotoxic, but ceased to be so within 76 days.     

Chemical restrictions of roots in Ultisol subsoils lessened by long-term management

Exchangeable Al in subsoils of Ultisols in the southeastern USA can restrict rooting depth. Downward movement of basic cations (Ca, Mg, and K), applied as lime and fertilizer, may diminish that restriction over time. Materials from the argillic horizon were collected from three paired sites, having managed (long-term cropping) and nonmanaged topsoils (Typic Paleudults and Hapludults). One managed site was cropped continuously for 15 yr while the others were cultivated for more than 30 yr. Concentrations of extractable cations and other nutrients from the paired sites were compared to determine the magnitude of change due to management. The ability of the subsoils to support plant growth was evaluated in a missing-nutrient greenhouse experiment with sorghum [Sorghum bicolor (L.) Moench]. Subsoils of managed sites had greater effective cation-exchange capacity (CEC) and base saturation than those of non-managed sites. While availabilities of Ca, Mg, and K in subsoils of nonmanaged sites were inadequate to support maximal plant growth, they were adequate in subsoils of managed sites. Compared with nonmanaged sites, KCl-exchangeable Al in subsoils of managed sites was 23% lower at the 15-yr location and 65 and 100% lower at the two other locations. In the absence of lime, sorghum growth was almost totally inhibited on nonmanaged subsoils amended with optimum nutrients. On the managed subsoils, where 100, 65, and 23% of the nonmanaged exchangeable Al had been neutralized by topsoil fertilization and liming, growth reductions under the same conditions were 0, 50, and 100%, respectively. Thus, relatively long-term management had improved these Ultisol subsoils for root growth and development.     

Air Pollution and Lichen Physiology. Physiological Responses of Different Lichens in a Transplant Experiment Following an SO2-Gradient

Four lichen species, Parmelia sulcata Taylor, Hypogymnia physodes (L.) Nyl., Cetraria islandica (L.)Ach., and Bryoria fuscescens (Gyelnik) Brodo andHawksworth were exposed during autumn and winter at differentsites of the Erzgebirge (Ore Mountains), the Fichtelgebirge andcontrol sites. All lichens tested became visibly damaged withtime. Thallus bleaching started from the edges and went on tothe centre of the thallus. Sites of facilitated gas exchangelike the soralia of P. sulcata and the pseudocyphelles ofC. islandica became preferentially bleached. The sulfateconcentration increased with exposure time reaching 200% ofunpolluted controls. In contrast to coniferous trees (e.g. Picea abies), further exposure lead to a reduction in the S-concentration in the lichens, as sulfate and otherintracellular metabolites were leached from the thalli due tomembrane damage. The changes in the K-concentration proved tobe an excellent measure for membrane leakiness; it wascorrelated with time of exposure and with SO₂ concentrations at the different sites. Photosynthetic capacityand respiration were also strongly affected. Depending on theSO₂-dose, the Bryoria species were unable tophotosynthesize as early as 4–8 weeks after exposure, whereasCetraria and Hypogymnia showed clear reduction intheir ability to photoreduce CO₂ within 8–10 weeks ofexposure in the field. Parmelia sulcata was found to bethe most tolerant species. After 3–4 months, photosynthesis wasreduced by only 30%. The bioindicative value of theseobservations is discussed.     

General principles of retrovirus immunodetection tests.

Because infecting retroviruses contain protein and glycoprotein antigenic determinants that can be readily distinguished from host cell determinants, the development of immunologic detection systems, immunodetection tests, or immunoassays capable of identifying antigens of some retroviruses (oncoretroviruses) in blood, body fluids, or cells is possible. Conversely, detection of antibodies produced by animals against some infecting retroviruses can also be used to identify current infections of lentiretroviruses and some oncoretroviruses. Studies of various microorganisms by various immunodetection systems indicate that the most specific and sensitive assays are immunofluorescence, radioimmunoassay, and immunoblot (western blot) analysis, followed by sensitive but less specific ELISA and agglutination assays, and finally by even less sensitive but very specific isolation in culture and double immunodiffusion techniques. The first test used routinely for clinical detection of any retrovirus was the immunofluorescent antibody test, introduced in 1972, for detection of FeLV infection in pet cats. Since then, tests for human retroviruses, the human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2 and the human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) have been introduced for routine use in human medicine. Recently, retroviral tests for a second feline retrovirus, the feline immunodeficiency virus (FIV) have been introduced in veterinary medicine. General principles of sensitivity, specificity, true-positive and -negative rates, false-positive and -negative rates, and positive and negative predictive values apply to all methods used for detection of retroviral infections.     

Upper respiratory obstruction in foals, weanlings, and yearlings

Upper airway obstruction may result from nasal, pharyngeal, or tracheal diseases. In the young horse, a relatively severe obstruction usually is present before clinical signs are evident. This article reviews the clinical manifestations, diagnostic features, treatment, and outcome of commonly encountered conditions of the nasal passages, pharynx, larynx, and trachea in young horses.     

Performance of Juvenile Coho Salmon Oncorhynchus kisutch Fed Diets Containing Meals from Fish Wastes, Deboned Fish Wastes, or Skin-and-Bone By-Product as the Protein Ingredient

The suitability of meals derived from fish processing wastes as the protein fraction in practical diets for hatchery-reared coho salmon was investigated. The study compared the performance of coho salmon fed diets containing three products: a skin-and-bone meal (SB), a deboned meal (DM), and a whole-fish meal (WM) made directly from the fish wastes. A commercial trout diet (CO) was fed to a fourth treatment group. Diets were fed at 3% of body weight per day to juvenile coho salmon for 12 wk. Survival (> 94%) was not significantly different among treatment groups. Average fish weight, feed conversion ratio, whole body proximate and mineral composition, and protein and phosphorus retention were compared. There were no significant differences after 12 wk of feeding in fish weight between WM, DM, and CO, but SB had significantly lower weight and whole body lipid, and significantly higher ash. Compared to WM, DM had a significantly lower feed conversion ratio and higher retention of protein and phosphorus, but these indices were not significantly different from CO. It is concluded that DM is a potentially superior protein ingredient compared to WM, while specific characteristics of SB will limit its use as a protein source in feeds for salmonids. However, SB may prove to be a suitable mineral supplement when added at a low level. Utilization of fish processing wastes in salmonid diets could be a commercially viable alternative to direct disposal of processing wastes.     

Hypophosphatemia and Hemolytic Anemia Associated With Diabetes Mellitus and Hepatic Lipidosis in Cats

Hypophosphatemia associated with hemolytic anemia was diagnosed in five cats with diabetes mellitus and in one cat with idiopathic hepatic lipidosis. The hematocrit began decreasing within 24 to 48 hours after documented hypophosphatemia in each case. The anemia resolved in all five surviving cats. Because of the temporal relationship and lack of other detectable causes, hemolytic anemia was presumed to be caused by hypophosphatemia. There were increased Heinz bodies in three of six hypophosphate-mic cats during episodes of hemolysis. Intravenous potassium phosphate administration corrected the hypophosphatemia in four of five cats. The effective dosages of intravenous phosphate ranged from 0.011 to 0.017 mmol of phosphate/kg/h for 6 to 12 hours. Hypocalcemia (5.4 to 8.7 mg/dL) occurred in four of five cats treated with intravenous phosphate; however, only one cat developed clinical signs attributable to hypocalcemia. Based on this retrospective study, we recommend monitoring serum phosphorus concentration every 6 to 12 hours in cats likely to become hypophosphatemic. Treatment of hypophosphatemia in cats is warranted because of the apparent increased susceptibility of cats to hypophosphatemia-induced hemolysis. Cats with severe hypophosphatemia (≤1.5 mg/dL) should be given oral or parenteral phosphate if contraindications do not exist. (Journal of Veterinary Internal Medicine 1993; 7:266–271. Copyright © 1993 by the American College of Veterinary Internal Medicine.)