Existence of two O-serotypes in the fish pathogen Pseudomonas anguilliseptica

The serological characteristics of a group of 32 Pseudomonas anguilliseptica strains isolated in Spain from seabream (Sparus aurata) and turbot (Scophthalmus maximus) were compared with a total of 18 collection strains of this bacterial species with different geographical and host origin. The employment of different techniques, including slide agglutination, microagglutination and dot blot, allowed us to establish two serological groups, one comprising practically all the eel isolates, and the other including the majority of isolates from other fish species. The study of the lipopolysaccharides (LPS) and outer membrane proteins (OMP) corroborated these results, indicating that the serological differences among strains are due to the somatic antigen and not to antigenic determinants of protein nature. Therefore, a serological scheme of two "O" serotypes is proposed for P. anguilliseptica. The results obtained will be of importance for epidemiological studies as well as for the design of adequate vaccine formulations.     

Date of pruning of Guazuma ulmifolia during the rainy season affects the availability, productivity and nutritional quality of forage during the dry season

Guazuma ulmifolia was experimentally pruned to determine when pruning should begin during the rainy season in order to extend the production of green tree-forage during the dry season. Three prunings (P-1, P-2, and P-3) were performed (5 weeks apart) during the rainy season (August, September, and October) and four forage harvests (C-a, C-b, C-c, and C-d) (3 weeks apart) took place during the dry season (February, March, and April). Over 2 years, forage biomass production was evaluated as total biomass (g dry matter tree^?1), biomass of the morphological components (leaves, stems, and dead matter), and nutritional quality (crude protein, fiber, lignin, and digestibility). Date of pruning affected the production of total biomass (P = 0.001) with the earliest pruning (P-1) yielding the greatest forage quantity, while stems (P = 0.022) and dead matter (P = 0.032) varied due to a year by pruning interaction. Total biomass, leaves, stems, and dead matter varied by the interaction between forage harvest and year for all four variables (P < 0.037). In both years, the largest forage harvest occurred in C-b (P < 0.05), leaf production was highest in C-a and C-b (P < 0.001), stem production was greatest in C-b (P = 0.013) and dead matter was highest in C-b and C-d (P = 0.002). Leaf crude protein ranged between 10 and 19 %, and the interaction of pruning by forage harvest by year was significant (P = 0.035). Digestibility, neutral and acid detergent fiber and lignin differed significantly because of the interaction between forage harvest and year (P < 0.005), with February showing the lowest values for fiber and the highest digestibility. The best time to prune G. ulmifolia is in August so that the young trees will produce more total biomass with a higher crude protein content. The most suitable moment for forage harvest is in February when the trees have more leaves with greater digestibility and less fiber.     

Does Stocking Rate Manipulation Promote Pasture Sustainability in the Humid Tropics?

Stocking rate manipulation was examined as a means of improving plant diversity (as a measure of pasture sustainability and forage value) in a native grass pasture used for dairy production in the humid tropics of Veracruz, Mexico. Given that environmental impact reduces biotic diversity, plant phylogenetic and functional diversity should decline with increased stocking rate. Stocking rates of 2, 3, and 4 cows · ha^?1 and a rotational grazing plan of 3 d of occupation and 27 d of rest per pasture were applied continuously over 5 yr. Across 200 quadrats in each of two replicate paddocks per treatment, observed species richness, phylogenetic diversity (average taxonomic distinctness based on species presence/absence), and functional diversity (life-cycle duration and growth habit) were assessed. Most species were forb/herbs and forb/herb-subshrubs. Perennial species declined with increased stocking rate (F = 16.36, 0.05 > P > 0.02) while annual-perennial species increased (F = 76.88, 0.01 > P > 0.005); the proportion of annual species was least prominent and did not differ significantly. Observed species richness and phylogenetic diversity did not differ significantly with stocking rate. The correlation between functional diversity for life-cycle duration and phylogenetic diversity was significant and positive, suggesting that plant communities were predominantly assembled randomly from the surrounding species pool rather than through interspecies interactions acting to naturally filter immigrant species, thus leading to more opportunistic and undesired species. Although grazing pressure was not sufficient to alter indices or production measures, they did reveal shifts that may precede further pasture decline, indicating pasture sustainability was not being achieved. These rapid assessment methods permit monitoring for early warnings of reductions in pasture sustainability and forage quality for cattle.     

Breeding and scientific advances in the fight against Dutch elm disease: Will they allow the use of elms in forest restoration?

New Forests - Elms (Ulmus spp.) were once dominant trees in mixed broadleaf forests of many European territories, mainly distributed near rivers and streams or on floodplains. Since ancient times...     

Sterol oxidation in ready-to-eat infant foods during storage

The effect of storage on sterol oxidation of ready-to-eat infant foods was evaluated. Two different liquid infant foods (honey or fruits flavors), prepared with milk and cereals, were stored for 0, 2, 4, 7 and 9 months at 25 degrees C. Sterol oxidation products (SOP) were isolated by cold saponification, purified by silica solid-phase extraction, and analyzed by gas chromatography (GC) and GC-mass spectrometry. beta-Sitosterol was the most representative sterol, followed by cholesterol and campesterol. No significant differences in the total and single SOP content (0.8-1 mg/kg of product) were observed with respect to storage time and type of sample; the main SOP found was 7-ketositosterol (<0.2 mg/kg of product). The extent of stigmasterol oxidation (2.9%) was higher than that of cholesterol (1.9%) and beta-sitosterol (1.4%). The type and quality of raw materials, as well as the processing conditions, seem to greatly influence SOP formation and accumulation in infant foods.     

Effect of different wood pretreatments on the sorption-desorption of linuron and metalaxyl by woods

The sorption-desorption of two different pesticides, linuron and metalaxyl, by woods was studied. Sorbent/solution ratio and sorption kinetics were also determined. Untreated wood and water, NaOH, HCl, and octadecyltrimethylammonium bromide (ODTMA) treated pine (softwood) and oak (hardwood) were used as sorbents. Linuron and metalaxyl were sorbed by untreated woods up to 80 and 40%, respectively, in a short time when the sorbent/solution ratio of 1:10 was used. Sorption of pesticides was significantly higher by pine, having higher lignin content, than by oak. Freundlich sorption constants (K(f)) were 96.2 and 74.4 (linuron) and 8.28 and 4.95 (metalaxyl) for untreated pine and oak woods and increased 1.04-2.35-fold (linuron) and 1.33-2.17-fold (metalaxyl) when woods were treated. The sorption was higher by HCl- and ODTMA-treated woods. Additionally, Freundlich desorption constants also indicated greater sorption irreversibility of both pesticides for treated woods than for untreated woods. The results revealed wood residues as a promising, low-cost, and environmentally friendly material to immobilize pesticides in soils, preventing water contamination. Wood treatments aimed at removing soluble wood extracts or at modifying wood chemical structure could increase their sorption capacity.     

Endotracheal stenting therapy in dogs with tracheal collapse

Tracheal collapse in dogs is a common respiratory disorder, typically presenting with a history of chronic cough, increasing respiratory difficulties, and episodes of dyspnoea. Medical treatment is the therapy of choice and surgical repair is considered when patients do not respond well. Minimally invasive endotracheal stenting is a promising new therapy under investigation, but there remain significant challenges to overcome potential complications. The purpose of this article is to provide a comparative overview of intra-luminal stenting of the trachea in human and veterinary medicine. The currently available stents and their potential clinical application to the veterinary patient will be discussed.     

Reproductive behavior in hair sheep rams under tropical conditions

The reproductive efficiency of sheep herds depends to a great extent on the ram. Male reproductive evaluation allows to select for the best and eliminate those with reproductive problems. The objective was to evaluate the effect of breed and age group on the reproductive behavior of hair sheep rams in the tropics of Mexico. Pelibuey (n?=?42), Blackbelly (n?=?30), Dorper (n?=?44), and Katahdin (n?=?30) rams of two age groups: young (n?=?74, 1–1.5 years old) and adult (n?=?72, 2–4 years old) were evaluated. Serving capacity (10-min duration) and breeding soundness evaluation (BSE) tests were carried out in each ram. In the first test, rams were classified as suitable and unsuitable, and in the BSE test, they were classified as satisfactory, questionable, or unsatisfactory. The response variables were analyzed using chi-square test or analyses of variance (ANOVA). ANOVA included the fixed effects of breed, age group, and their interaction. In the serving capacity test, 79.5% of the rams were considered suitable, with no breed differences (P?>?0.05). Adult rams (90.3%) had the highest proportion of suitable rams (P?<?0.05). In the BSE test, 80.2% of the rams were satisfactory; only breed being significant (P?<?0.05). Pelibuey breed had the highest proportion of satisfactory rams (91.4%). Breed × age interaction was no significant for any trait. After serving capacity and BSE tests, a high proportion of rams was found not suitable for reproduction (36.3%), which is expected to cause low fertility in the flock.

     

Effects of dietary arginine on hematological parameters and innate immune function of channel catfish

The effects of elevated dietary arginine on the hematology and immune function of juvenile channel catfish Ictalurus punctatus were evaluated by means of in vivo and in vitro experiments. Healthy juvenile channel catfish (average weight, 34.8 g) were fed casein-gelatin-based diets containing 28% crude protein and supplemented with crystalline L-arginine (ARG) at 0.5, 1, 2, or 4% of diet. An intact-protein diet containing 1.3% arginine also was included to investigate the effects of amino acid form (crystalline-free amino acids versus intact protein). Each purified diet was fed to apparent satiation to triplicate groups of fish for 6 weeks. At the end of the experimental feeding period, the fish were injected intraperitoneally with two doses (3 d apart) of 2 mg lipopolysaccharide/kg body weight. Six days after the initial injection, the fish were anesthetized and tissue samples were obtained to evaluate hematological and humoral and cellular immune parameters, including phagocytic activity of peritoneal macrophages, hemoglobin, hematocrit, mean corpuscular volume (MCV), blood cell counts, plasma protein, and hepatic superoxide dismutase activity. High dietary levels (4% ARG) resulted in significantly higher levels of hemoglobin, hematocrit, and circulating erythrocytes. Dietary ARG did not significantly affect MCV and the number of circulating leukocytes, lymphocytes, eosinophils, and monocytes. In vitro, a moderate level (2 mM) of ARG in the culture media was found to be ideal in significantly enhancing phagocytosis. This study demonstrates that some aspects of the immune system of channel catfish are sensitive to changes in dietary ARG.     

Intensive rearing of juvenile crayfish (Pacifastacus leniusculus,Astacidae) during the first 6 months: effects of size grading

Recent advances in crayfish feeding have enabled the development of size grading studies from the start of first‐feeding. A 180‐day experiment aimed at intensive rearing of Pacifastacus leniusculus was carried out under controlled conditions, evaluating the effects of size grading at two different periods from the onset of exogenous feeding. Stage 2 juveniles were stocked in fibreglass tanks at a density of 100 m², and fed a dry diet for salmonids combined with restricted amounts of Artemia cysts. Five groups were tested: no grading, grading at 60 days (large and small size) and grading at 100 days (large and small size). After 6 months, no significant differences were found in the survival among groups (mean: 73.06%). The highest final growth (pooled results from upper and lower classes: 17.39 mm carapace length, 1.43 g weight) was achieved by the crayfish sorted at 60 days, showing significant differences from the ungraded group. Smaller crayfish graded at 60 days grew significantly faster than smaller crayfish graded at 100 days. The food conversion ratio was lower in the graded groups (mean: 2.64), showing significant differences from the ungraded group (3.23). This study shows that size grading allows a better performance and an improved feeding efficiency.