Gas-liquid chromatographic method for perfluidone residues in rice grains and husks

A gas-liquid chromatographic method using electron-capture detection is described for the determination of perfluidone residues in rice grains and husks. The procedure consists of extraction, purification on an anion-exchange resin, methylation and further clean-up (if necessary) by adsorption on “Florisil”. The recoveries from fortified rice grains and husks were respectively 73.5–98% and 77–104% in the range 0.01–0.50 mg/kg. Sensitivity permits detection of perfluidone at 0.005 mg/kg level.     

Effects of dietary cation-anion difference on blood cortisol and ACTH levels in reproducing ewes

Formulation of rations to induce a compensated metabolic acidosis in the post-partum cow has proved a useful strategy for prevention of milk fever. Such acidification improves the ability of the animal to maintain calcium homeostasis by promoting the absorption of calcium from the intestine and mobilization of calcium from the bone. In humans, an acidogenic diet results in mild metabolic acidosis in association with a state of cortisol excess and this increase in plasma cortisol may increase bone catabolism. The objective of our experiment was to induce acidification by anionic salt supplementation and to study the effects of anionic supplementation on plasma cortisol and adrenocorticotropic hormone (ACTH) levels in sheep. Twenty-seven twin-bearing sheep were assigned to two experimental groups and a control group, depending on dietary cation-anion difference (DCAD) (+272.6, -88.9 and +164.5 mEq/kg DM respectively). Sheep assigned to each dietary treatment received their respective rations beginning 6 weeks pre-partum and continuing until 12 days post-partum. Anionic diet induced a non-respiratory systemic acidosis in association with a mild increase in plasma cortisol concentration without changes in plasma ACTH levels. Our data suggest that the mild hypercortisolism observed in sheep fed the anionic diet may not be an effector for bone resorption induced by anionic salts. A mild hypercortisolism of this magnitude may lead to osteoporosis but this might require many years of adrenal hypersecretion while anionic salts are only used during the last weeks of pregnancy.     

Influence of some 1,3,5-triazine herbicides on peroxidase activity in corn seedlings

The effect of some 1,3,5-triazine herbicides, on the rate of oxidative decarboxylation of tryptophan by peroxidase from corn seedlings, varied with the concentration. Atrazine was stimulatory in vivo at 10-⁶M but not at 10⁸ M or lower, whereas terbutryne was inhibitory at 10-⁶M but not at 10-⁸M or below. Prometryne inhibited enzyme activity at 10-⁶M and stimulated it at 10-¹⁰M and at 10¹²M, while simazine caused stimulation at 10-⁶M and inhibition at 10^?10M and 10^?12M. Atraton reduced enzyme activity at 10^?6M and 10^?8M but had no effect at 10^?10M and 10^?12M. When peroxidase activity was assayed in acetone-dried powders from seeds, harvested from fields that had received typical atrazine applications, the quantities of tryptophan consumed were significantly less than the quantity determined in the control powder. From the results obtained, by incorporating dealkylated and 2-hydroxy metabolites of atrazine at 10^?6M into the culture solutions, it seems possible that the inhibition observed may have been due to the presence of 4-amino-6-ethylamino-1, 3, 5-triazin-2-ol and/or 4, 6-diamino-1, 3, 5-triazin-2-ol residues in seeds from treated plots, even if, in previously reported experiments, analyses had not detected their presence.     

Cytoarchitecture, morphology, and lumbosacral spinal cord projections of the red nucleus in cattle

OBJECTIVE: To analyze the morphology, cytoarchitecture, and lumbosacral spinal cord projections of the red nucleus (RN) in cattle. ANIMALS: 8 healthy Friesian male calves. PROCEDURES: Anesthetized calves underwent a dorsal laminectomy at L5. Eight bilateral injections (lateral to the midline) of the neuronal retrograde fluorescent tracer fast blue (FB) were administered into the exposed lumbosacral portion of the spinal cord. A postsurgical calf survival time of 38 to 55 days was used. Following euthanasia, the midbrain and the L5-S2 spinal cord segments were removed. Nissl's method of staining was applied on paraffin-embedded and frozen sections of the midbrain. RESULTS: The mean length of the RN from the caudal to cranial end ranged from 6,680 to 8,640 microm. The magnocellular and parvicellular components of the RN were intermixed throughout the nucleus, but the former predominate at the caudal portion of the nucleus and the latter at the cranial portion with a gradual transitional zone. The FB-labeled neurons were found along the entire craniocaudal extension of the nucleus, mainly in its ventrolateral part. The number of FB-labeled neurons was determined in 4 calves, ranging from 191 to 1,469 (mean, 465). The mean cross-sectional area of the FB-labeled neurons was approximately 1,680 microm2. CONCLUSIONS AND CLINICAL RELEVANCE: In cattle, small, medium, and large RN neurons, located along the entire craniocaudal extension of the RN, contribute to the rubrospinal tract reaching the L6-S1 spinal cord segments. Thus, in cattle, as has been shown in cats, the RN parvicellular population also projects to the spinal cord.     

Comparison of Selected Nonlethal Samples from Adult Steelhead for Detection of Infectious Hematopoietic Necrosis Virus Using Cell Culture

Abstract

Nonlethal sampling techniques have previously been evaluated for detection of a variety of viral salmonid pathogens. However, many of these studies have used molecular assays in lieu of widely accepted cell culture techniques to evaluate the sampled tissues. Samples were collected from female steelhead Oncorhynchus mykiss broodstock using three potential nonlethal sampling methods (mucus/skin scrape, pectoral fin clip, and gill tissue biopsy) and evaluated for the presence of infectious hematopoietic necrosis virus (IHNV) via cell culture techniques. The results were compared with those from samples collected using a standard lethal sampling method (pooled anterior kidney and spleen tissues) applied to the same fish. Of the three nonlethal sampling techniques that were evaluated, fin clipping was the easiest and least invasive method. Furthermore, fin tissue was as sensitive as or more sensitive than kidney/spleen tissue for detecting IHNV in this population of fish. However, with the exception of gill tissue, the nonlethal samples did not appear to be appropriate surrogates for lethally collected tissues with regard to identifying an active infection in a particular fish. Nevertheless, nonlethal sampling coupled with cell culture appears to be suitable for helping to define the IHNV status of a steelhead population.

Received July 27, 2016; accepted December 11, 2016 Published online March 21, 2017     

Effect of peripartal administration of mycobacterium cell wall fraction on health and fertility of Holstein cows under organic-certified management

The main objective of this study was to evaluate the effect of peripartal administration of a commercially available nonspecific immune stimulant (mycobacterium cell wall fraction; MCWF [Amplimune, NovaVive Inc., Napanee, ON, Canada]) on the incidence of disease during early lactation and subsequent fertility of dairy cows. A second objective was to characterize the dynamics of circulating white blood cells (WBC) and metabolic markers following treatment administration. Cows in an United States Department of Agriculture (USDA) organic-certified dairy herd were blocked by parity and, based on sequential calving dates, randomly assigned to receive two injections (5 mL s.c.) of either a placebo (saline solution) as a control (CON; n = 71) or MCWF (n = 65) at enrollment (7 d before expected calving) and within 24 h after calving. Blood samples were collected from a subsample of the study population (MCWF = 16; CON = 18) for WBC count at enrollment, at day 2 post enrollment, and at days 1, 3, 7, and 14 after calving. Serum fatty acids, beta-hydroxybutyrate, and Ca concentrations were determined at days 1 and 7 postpartum (MCWF = 21; CON = 21). Main outcome variables included incidence risk of peripartal and early lactation health disorders and pregnancy at first artificial insemination (AI), at 100, and at 150 days in milk (DIM). In addition, the average daily milk yield up to 90 DIM and death and live culling before 305 DIM were compared. Treatment effects were assessed using multivariable logistic regression, time-to-event analyses, and repeated measures analysis of variance (ANOVA). A treatment effect on the incidence risk of some of the health disorders in the study was established. Incidence risk of metritis and clinical mastitis <28 DIM was smaller in MCWF than in CON cows (36.9% vs. 50.7% and 6.3% vs. 19.7%, respectively). On the contrary, the incidence risk of respiratory disease <28 DIM was smaller in CON (0%) than in MCWF (7.7%). Reproductive performance of multiparous cows was affected by MCWF administration: pregnancy at first AI and pregnancy at 100 and 150 DIM were greater in MCWF than in CON (35.6% vs. 19.2%; 51.1% vs. 25.0%; and 64.4% vs. 40.4%, respectively). Overall, median intervals from calving to pregnancy were 90 vs. 121 d in MCWF and CON cows, respectively. No treatment effects on the dynamics of circulating WBC or in postpartum metabolic status were established. No differences for milk yield or for the proportion of cows that survived up to 305 DIM were determined, although cows in MCWF left the herd earlier than cows in CON. In conclusion, incidence risks of metritis and mastitis in early lactation were smaller in cows receiving MCWF, whereas the incidence risk of respiratory disease was smaller in CON. Fertility significantly improved in MCWF compared with CON cows. As this study was performed in an organic-certified dairy, specific health and reproductive management practices may affect the external validity of the current findings.     

Mixed-effect non-linear modelling for diameter estimation along the stem of Tectona grandis in mid-western Brazil

This study evaluated the efficiency of taper functions and the application of mixed-effect modelling for diameter estimation along the stems of Tectona grandis. We sampled 266 trees of Tectona grandis, measuring the diameter at relative heights for volume determination, grouping the data according to three form-factor classes. Six taper functions were fitted, selecting the function with better fit performance. Six taper functions were fitted, selecting the function with better fit performance. The selected function was fitted in its basic formulation, and with the mixed non-linear modelling technique in different scenarios, and for the stem stratified in three portions of the total height. The precision and selection of the adjusted models were evaluated regarding the coefficient of determination, standard error of estimate, the Akaike information criterion, bias, quadratic error and absolute bias. According to the statistical criteria used, the model of Kozak was selected for the adjustments. For diameter estimation, the scenario with two coefficients as random effects provided an accuracy increase of 11.91%, and the mixed non-linear modelling better estimated the stem diameter for the stratified stems. In conclusion, the model of Kozak can be used to describe the stem shape of Tectona grandis, and the mixed-effect non-linear model approach was the best technique to estimate diameter along the stem of Tectona grandis.     

Dietary Photoprotective Compounds Ameliorate UV Tolerance in Shrimp (Pleoticus muelleri) through Induction of Antioxidant Activity

The aim of this study was to determine the effects of ultraviolet radiation (UVR) on bioaccumulation of UV‐absorbing compounds acquired through the diet, in larvae and postlarvae of Pleoticus muelleri, and to assess tissue antioxidant activity, survival, and development. Mysis stage I were exposed to two artificial radiation treatments: M‐PAR (photosynthetically active radiation, range = 400–700 nm) and M‐PAR + UVR (280–700 nm). The experimental larvae received a mixed dietary treatment of Artemia persimilis and the microalga Pavlova lutheri, reared under two radiation regimes: PAR (D‐PAR) and PAR + UVR (D‐PAR + UVR). Shrimp from all treatments reached 8 d postlarval stage (PL8), except those under M‐PAR + UVR treatment fed the D‐PAR‐cultured algae, which had 0% survival. Larvae in M‐PAR + UVR and M‐PAR treatments fed with D‐PAR + UVR diet presented the highest survival rates (70 and 75%, respectively), with 37 and 41% increase in PL size. UV‐absorbing compounds were detected in microalgae and PL subject to PAR + UVR treatments. Antioxidant activity, quantified by measuring the free‐radical 1,1‐diphenyl‐2‐picrylhydrazyl in homogenates of PL8, decayed drastically under radiation treatment M‐PAR + UVR fed with algae of the D‐PAR + UVR treatment. It is concluded that the bioaccumulation of UV‐absorbing compounds and the highest antioxidant activity in PL could improve the biochemical and photophysiological responses of shrimp under UVR stress.     

Weed seedling emergence in contrasting fodder crop systems following 30 years of cultivation in the lowlands of Northern Italy

Five fodder crop systems of different intensity (ranging from a double annual crop of Italian ryegrass + silage maize to a permanent meadow) were adopted for 30 years in the lowlands of Northern Italy under two input levels, differing mainly in their provision of organic fertiliser (manure). Herbicides were used in the maize crops included in all systems, except the meadow. After 30 years, the weed seedbank of all systems and input levels were assessed by the seedling emergence technique on soil samples from each plot. The cropping systems determined the abundance and composition of the weed assembly. Relatively few, frequent species made up the majority of the emerged seedlings in all systems, and there was no relationship between the total number of emerged seedlings and the mean number of species recorded in the different systems. Arabidopsis thaliana and Oxalis corniculata were abundant in the annual double crop and in the 3- and 6-year rotations that also comprised the annual double crop. These weeds, however, were unlikely to represent a major threat to the crops, due to their vigour and growth period. The permanent meadow tended to greater weed biodiversity than the other systems. The application of manure favoured the seedbank of species such as Lolium multiflorum, Digitaria sanguinalis and A. thaliana. Weed communities in the different systems were mainly determined by herbicide application, (through the ability of weeds to avoid its effects, determined by the weed life history and emergence period) and manure application (with its possible dual effect of spreading weed seeds and favouring nitrogen-responsive weeds).     

Secondary Stress Responses in Juvenile Brazilian Flounder,Paralichthys orbignyanus,throughout and after Exposure to Sublethal Levels of Ammonia and Nitrite

This study investigated the secondary stress responses of Paralichthys orbignyanus exposed to ammonia and nitrite and after recovery. Fish were exposed to 0.12, 0.28, and 0.57 mg NH₃‐N/L, or 5.72, 10.43, and 15.27 mg NO₂‐N/L for 10 d followed by the same time length for recovery. Ammonia‐ and nitrite‐free water was used as a control treatment. Blood samples were collected after 1, 5, and 10 d of exposure and after recovery. Fish exposed to ammonia presented lower and higher glucose levels after 10 d of exposure and recovery, respectively. Ammonia induced initial and transient ionic disturbances and metabolic alkalosis. Nitrite exposure caused hyperglycemia, increased plasma K⁺ levels, and respiratory alkalosis, whereas metabolic acidosis was observed after recovery. Increased proportion of monocytes and/or granulocytes and reduced number of lymphocytes were demonstrated in fish exposed to 0.28 mg NH₃‐N/L (Day 1) and 10.43 mg NO₂‐N/L (Day 5) and after recovery in the 0.28 and 0.57 mg NH₃‐N/L treatments. Exposure to ammonia decreased the proportion of granulocytes on Day 5. In conclusion, exposure to concentrations at 0.12 mg NH₃‐N/L and 5.72 mg NO₂‐N/L provoked physiological disorders in Brazilian flounder. Nonetheless, fish exposed to 5.72 mg NO₂‐N/L following a 10‐d recovery period showed complete resumption of homeostasis.