Lasting microbiological and biochemical effects of the addition of municipal solid waste to an arid soil

 This paper reports the effect of the addition of the organic fraction of municipal solid waste at two different rates on the microbiological and biochemical properties of an arid soil after 8 years. The vegetation that appeared spontaneously just after the amendment was still present 8 years later. The organic matter fractions were higher in the amended soil than in the control soil. Amended soil showed higher values of microbial biomass C, soil basal respiration and dehydrogenase activity than control soil, which reached values near to those of the natural soils in the area. The organic amendment had a positive effect on the activity of enzymes related with C, N, P cycles, particularly when the amendment was at the highest dose. This effect could be also observed on the activity of extracted enzymes. The results indicated that the addition of urban waste could be a suitable technique with which to restore soil quality. Received: 3 July 1998     

Alterations in the mineral nutrition of pea seedlings exposed to cadmium 1

A study was made of the effects of different levels of cadmium (Cd) in the nutrient solution (0.0, 1.5, and 6.0 mg/L Cd) on the assimilation of nitrate (NO₃ ^‐) and the uptake and distribution of cationic nutrients in pea (Pisum sativum cv. Argona) seedlings. Cadmium treatment resulted in an accumulation of NO₃ ^‐ in the root, indicating an alteration in NO₃ ^‐ translocation to the shoot. This was related to a decrease in the nitrate reductase (NR) activity in the shoot, severely inhibiting NO₃ ^‐ assimilation, and associated to a reduction in fresh tissue weight and in their relative water content. The concentration of potassium (K) decreased in both root and shoot, but its relative distribution between those tissues was not affected by the presence of Cd. Among other cationic nutrients, manganese (Mn) was the most affected, its concentration constantly decreased concomitantly with the increase in Cd supply. The distribution of Mn between shoot and root revealed that more was accumulated in the shoot than in the root, opposite to the distribution of NO₃ ^‐ The ‘shock’ addition of 6.0 mg/L Cd in a short‐term experiment confirmed that the transport of NO₃ ^‐ to the aerial part was reduced after 72 h of treatment and Cd displaced Mn from its physiological positions in root tissues.     

Effect of oral administration of a calcium chloride gel on blood mineral concentrations, parturient disorders, reproductive performance, and milk production of dairy cows with retained fetal membranes.

OBJECTIVE: To assess the effect of oral administration of CaCl2 gel on blood mineral concentrations, parturient disorders, reproductive performance, and milk production of dairy cows with retained fetal membranes (RFM). DESIGN: Randomized field trial. ANIMALS: 20 cows that calved normally and were not treated with CaCl2 gel (group 1), 20 cows with RFM that were treated with CaCl2 gel (group 2), and 20 cows with RFM that were not treated with CaCl2 gel (group 3). PROCEDURE: Group-2 cows were treated orally with CaCl2 gel (54 g of calcium) 24 and 48 hours after parturition. RESULTS: Administration of CaCl2 gel 24 and 48 hours after parturition did not have a significant effect on serum normalized calcium, total calcium, magnesium, or phosphorus concentrations or on incidence of metritis or left displacement of the abomasum, days to first insemination, pregnancy status after first insemination, or milk production. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of CaCl2 gel 24 and 48 hours after parturition did not have significant effect on blood mineral concentrations, parturient disorders, reproductive performance, and milk production in dairy cows with RFM.     

Risk factors associated with fecal Salmonella shedding among hospitalized horses with signs of gastrointestinal tract disease

OBJECTIVE: To estimate prevalence of and identify risk factors for fecal Salmonella shedding among hospitalized horses with signs of gastrointestinal tract disease. DESIGN: Cross-sectional study. ANIMALS: 465 hospitalized horses with gastrointestinal tract disease. PROCEDURE: Horses were classified as positive or negative for fecal Salmonella shedding during hospitalization by means of standard aerobic bacteriologic methods. The relationship between investigated exposure factors and fecal Salmonella shedding was examined by means of logistic regression. RESULTS: The overall prevalence of fecal Salmonella shedding was 13%. Salmonella serotype Newport was the most commonly isolated serotype (12/60 [20%]), followed by Anatum (8/60 [13%]), Java (13%), and Saint-paul (13%). Foals with gastrointestinal tract disease were 3.27 times as likely to be shedding Salmonella organisms as were adult horses with gastrointestinal tract disease. Adult horses that had been treated with antimicrobial drugs prior to hospitalization were 3.09 times as likely to be shedding Salmonella organisms as were adult horses that had not been treated with antimicrobial drugs prior to hospitalization. Adult horses that underwent abdominal surgery were 2.09 times as likely to be shedding Salmonella organisms as were adult horses that did not undergo abdominal surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a history of exposure to antimicrobial drugs prior to hospitalization and abdominal surgery during hospitalization were associated with Salmonella shedding in adult horses with gastrointestinal tract disease. Foals with gastrointestinal tract disease were more likely to shed Salmonella organisms than were adult horses with gastrointestinal tract disease.     

Optimum soybean lecithin contents in microdiets for gilthead seabream (Sparus aurata) larvae

The aim of the present study was to determine the optimum dietary levels of soybean lecithin (SBL) for seabream (Sparus aurata) larvae, and its influence on production performance and digestive enzymes activity. Larvae were fed five formulated microdiets with five levels of SBL. Complete replacement of live preys with the experimental microdiets for seabream larvae at 16 dph produced over 55% survival rates, particularly in fish fed with the highest levels of SBL. Moreover, increase in dietary SBL up to 80 g kg⁻¹ significantly improved larval growth, leading to high final total length and body weight. An increase in alkaline phosphatase activity with the elevation up to 80 g kg⁻¹ SBL was also found denoting a better maturation of the digestive system. Besides, there was a stimulatory effect of dietary SBL on PLA2 activity. Finally, increasing dietary SBL lead to better utilization of dietary highly unsaturated fatty acid, as it was reflected in their higher content in both neutral and polar lipid of the larvae. In summary, elevation of dietary SBL up to 80 g kg⁻¹ in microdiets for seabream significantly improved digestive enzymes activities, enterocyte maturation, utilization and deposition of dietary essential fatty acids and larval growth, as a consequence of a better digestion, absorption, transport and deposition of dietary nutrients.     

Risk factors for brucellosis seropositivity of goat herds in the Mexicali Valley of Baja California, Mexico

A case-control study was conducted in the Mexicali Valley to identify risk factors for goat-herd seropositivity for Brucella melitensis. Nineteen case herds (≥2 positive results with the 8% rose bengal plate test (RBT)) and 55 control herds (zero positive results in RBT), matched for herdsize and geographic location, were enrolled. Conditional logistic regression was used to construct a multivariable model of the odds of seropositivity using variables assessed in a questionnaire administered to goat ranchers. The final model for herd seropositivity included increased risk from importation of goats from other Mexican states, the presence of La Mancha breed does, and the presence of does born outside the herd. Increasing herdsize was also highly significant (p<0.01). In addition, a significant (p<0.05) positive association was found between the presence of seropositive dogs (as assessed by RBT) and seropositive goats on the same ranch.     

Use of organic amendment as a strategy for saline soil remediation: Influence on the physical, chemical and biological properties of soil

The effectiveness of adding two organic wastes (cotton gin crushed compost, CGCC, and poultry manure, PM) to a saline soil (Salorthidic Fluvaquent) in dryland conditions near Seville (Guadalquivir Valley, Andalusia, Spain) was studied during a period of 5 years. Organic wastes were applied at rates of 5 and 10 t organic matter ha⁻¹. One year after the assay began, spontaneous vegetation had appeared in the treated plots, particularly in that receiving a high PM dose. After 5 years the plant cover in this treated plot was around 80% (compared with the 8% of the control soil). The effect on the soils physical and chemical properties, soil microbial biomass, and six soil enzymatic activities (dehydrogenase, urease, protease, β-glucosidase, arylsulfatase, and phosphatase activities) were ascertained. Both added organic wastes had a positive effect on the physical, chemical and biological properties of the soil, although at the end of the experimental period, the soil physical properties, such as bulk density, increased more significantly in the CGCC-amended soils (23%) and the exchangeable sodium percentage (ESP) decreased more significantly in the CGCC-amended soils (50%) compared to the unamended soil. Water soluble carbohydrates and soil biochemical properties were higher in the PM-amended soils compared to the CGCC-amended soils (by 70% for water soluble carbohydrates, and by 34, 18, 37, 39, 40 and 30% for urease, protease, β-glucosidase, phosphatase, arylsulfatase and dehydrogenase activities, respectively). After 5 years, the percentage of plant cover was >50% in all treated plots and 8% in the control soil.     

Effects of Dietary Vitamin A on Juvenile Red Sea Bream Chrysophrys major

A 55-d feeding experiment was conducted to evaluate the effects of dietary vitamin A on growth of juvenile red sea bream Chrysophrys major . Nine semi-purified diets with supplemental retinol palmitate at levels of 0, 300, 600, 1,500, 3,000, 4,500, 6,000, 15,000 and 30,000 retinol eq/kg diet, were fed twice daily to triplicate groups of 10 juveniles per tank with an initial weight of 1.178 ± 0.001 g. Weight gain and specific growth rate increased with the increase of supplemental retinol palmitate in the diet up to a level of 6,000 retinol eq/kg diet, beyond which those indices tended to decrease slightly or to plateau. Significantly lower weight gain and specific growth rate were observed in fish fed with 0 and 300 retinol eq/kg diet. No significant differences were found in survival rates among the different levels of supplementation. The crude protein, lipid, moisture and ash contents in the whole body were not affected by the different vitamin A supplemental levels. Besides the reduced growth, fish fed with low levels of vitamin A supplement showed no other signs of deficiency. No hypervitaminosis A symptoms were observed in fish fed on high levels of supplementation. Fish fed on diets with 0 and 300 retinol eq/kg diet showed a significantly lower content of vitamin A (as a total retinol) in the liver than those in groups fed with higher levels of supplementation. Vitamin A was stored in the liver mainly as retinyl esters. Total retinal content of the eye showed no significant differences among the treatments; however, fish fed with 0 and 300 retinol eq/kg of diet had slightly higher concentrations. According to the results of the mean weight gain, specific growth rate and liver retinol content, the requirement of dietary vitamin A for juvenile red sea bream was estimated to be between 1,500 and 6,000 retinol eq/kg.     

Risk factors associated with development of poxvirus lesions in hospitalized California sea lions

OBJECTIVE: To identify risk factors that may predispose California sea lions (Zalophus californianus) to development of cutaneous poxvirus nodules during hospitalization in a rehabilitation center. DESIGN: Retrospective case-control study. ANIMALS: 90 California sea lions admitted to a rehabilitation center. PROCEDURE: Hospital records of 275 stranded California sea lions admitted to the rehabilitation center between January 1 and December 31, 2002, were reviewed. All California sea lions (n = 18) that developed > or = 1 cutaneous poxvirus nodule during hospitalization were classified as cases. Seventy-two California sea lions that did not develop poxvirus lesions during hospitalization were randomly selected (control group). The frequencies of various exposure factors prior to admission, at admission, and during hospitalization for cases and control sea lions were compared by use of logistic regression. RESULTS: California sea lions that had previously been admitted to the rehabilitation center were 43 times as likely to develop poxvirus lesions as sea lions admitted for the first time; those with high band neutrophil counts (> 0.69 X 10(3) bands/microL) at admission were 20 times less likely to develop poxvirus lesions than sea lions with counts within reference limits. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that sea lions with a history of prior hospitalization or band neutrophil counts within reference limits at admission were more likely to develop poxvirus lesions during hospitalization. Sea lions with histories of hospitalization should be kept in quarantine and infection control measures implemented to help prevent disease transmission to attending personnel and other hospitalized animals.