Production of Florida red tilapia in seawater pools: Nursery rearing with chicken manure and growout with prepared feed

Florida red tilapia (Oreochromis sp.) were reared in 23 m³ seawater (37 ppt) pools. Monosex males (1.3 g mean weight) were stocked at a density of 25 fish/m³ and reared to fingerling size (>10 g) in pools receiving either chicken manure applied at a rate of 105 kg/ha day⁻¹ or pelletized feed (30% protein) administered ad libitum. Following the nursery period, fingerlings in fed pools were reared through adult, marketable sizes.

After 20 days of nursery rearing, mean fish weights (5.7–9.6 g) and survival (77.5–98.6%) in manured pools ranged from less than to greater than values in fed pools (7.9–9.4 g and 95.5–98.2%). By day 33, while mean weights (11.3±0.4 g) and survival (84.5±5.2%) in manured pools were significantly less than those in fed pools (18.0±0.6 g and 95.9±1.4%), fingerling-size fish were obtained from manured pools at an overall productivity of 55 kg/ha day⁻¹.

After 170 days in fed pools, mean fish weight was 467±9 g, survival was 89.7±0.9%, and food conversion was 1.6±0.2. Daily weight gain achieved a maximum of 4.4 g day before a rapid decline in water temperature from 28–29°C to 24–25°C caused a loss of fish appetite and evidence of disease.

The results suggest that while nursery rearing of Florida red tilapia in seawater pools fertilized with chicken manure is feasible, considerable variability in fish performance among pools can be expected, despite identical management methods. In pools receiving prepared feed, high growth rates and survival through adult, marketable sizes suggests a potential for commercial production of Florida red tilapia in seawater.     

Utilization of stress in the development of an equine model for equine protozoal myeloencephalitis

Neurologic disease in horses caused by Sarcocystis neurona is difficult to diagnose, treat, or prevent, due to the lack of knowledge about the pathogenesis of the disease. This in turn is confounded by the lack of a reliable equine model of equine protozoal myeloencephalitis (EPM). Epidemiologic studies have implicated stress as a risk factor for this disease, thus, the role of transport stress was evaluated for incorporation into an equine model for EPM. Sporocysts from feral opossums were bioassayed in interferon-gamma gene knockout (KO) mice to determine minimum number of viable S. neurona sporocysts in the inoculum. A minimum of 80,000 viable S. neurona sporocysts were fed to each of the nine horses. A total of 12 S. neurona antibody negative horses were divided into four groups (1-4). Three horses (group 1) were fed sporocysts on the day of arrival at the study site, three horses were fed sporocysts 14 days after acclimatization (group 2), three horses were given sporocysts and dexamethasone 14 days after acclimatization (group 3) and three horses were controls (group 4). All horses fed sporocysts in the study developed antibodies to S. neurona in serum and cerebrospinal fluid (CSF) and developed clinical signs of neurologic disease. The most severe clinical signs were in horses in group 1 subjected to transport stress. The least severe neurologic signs were in horses treated with dexamethasone (group 3). Clinical signs improved in four horses from two treatment groups by the time of euthanasia (group 1, day 44; group 3, day 47). Post-mortem examinations, and tissues that were collected for light microscopy, immunohistochemistry, tissue cultures, and bioassay in KO mice, revealed no direct evidence of S. neurona infection. However, there were lesions compatible with S. neurona infection in horses. The results of this investigation suggest that stress can play a role in the pathogenesis of EPM. There is also evidence to suggest that horses in nature may clear the organism routinely, which may explain the relatively high number of normal horses with CSF antibodies to S. neurona compared to the prevalence of EPM.     

A randomized, double-blind, placebo-controlled trial to investigate the efficacy and safety of a Chinese herbal product (P07P) for the treatment of canine atopic dermatitis

A randomized, double-blind, placebo-controlled trial of P07P, a product derived from a traditional Chinese herbal remedy, was undertaken in 50 dogs with atopic dermatitis. Owners recorded a daily itch score for 4-14 days before treatment and during treatment. Packets of powder containing P07P or placebo were added to the food once daily for 8 weeks. Dogs were assessed for erythema, surface damage, overall coat condition and seborrhoea by the same investigator, as well as for pruritus and general demeanour, at 0 (visit 2), 28 (visit 3) and 56 (visit 4) days of treatment or at withdrawal. Investigator and owner assessments of response were recorded after 28 and 56 days of treatment or at withdrawal. The predefined primary outcome measure was the owners' assessment of response at the end of treatment. Nine of the 24 dogs (37.5%) in the P07P group but only 3 of the 23 dogs (13%) in the placebo group were considered to have improved, but this difference was not statistically significant (P = 0.09). There was a significantly higher withdrawal rate due to worsening of condition in the placebo group (P = 0.04). Mean daily itch score in the second 28-day period of the study was significantly higher than baseline in the placebo group (P = 0.01) but not in the P07P group (P = 0.30). Pruritus scores showed a significant deterioration from baseline at the final visit in the placebo group (P = 0.01) but not in the P07P group (P = 1.00). There was a significant difference between the groups in change from baseline in erythema score at visit 3 (P = 0.05). There were no significant differences (P > 0.05) in surface damage, seborrhoea, overall coat condition and general demeanour scores within or between the groups throughout the study. The product was well tolerated with no severe or serious adverse events recorded. P07P may be beneficial as a novel nonsteroidal therapy for the management of dogs with atopic dermatitis.     

Length-weight relationship of pond-raised milkfish in the Philippines

Milkfish from culture ponds were measured in the provinces of Bataan, Iloilo, and Pangasinan over the period December 28th, 1970, to November 9th, 1971. The overall length-weight relationship was computed from 6 304 measurements giving the equation: log W = ?5.0463 + 2.98895 log L, where W = weight in g and L = total length in mm. A table is presented giving calculated weights for milkfish in the length range 80–400 mm, which can be used to compute relative condition factors. Data were grouped according to lengths, province, food system, and months for separate comparisons.     

FC‐39 Successful management of canine atopic dermatitis using a plant extract: a randomized,double‐blinded,placebo‐controlled trial

This study evaluated the efficacy of Phytopica^TM, a proprietary blend of standardised plant extracts, in canine atopic dermatitis (AD). One hundred twenty dogs with perennial AD were recruited on the basis of history and clinical signs, and a positive intradermal allergen test or rFcεRIα serology to perennial allergens. Other pruritic dermatoses were eliminated by antimicrobial treatment, skin scrapings, Sarcoptes serology, flea control and a 6‐week food trial. Exclusion criteria included antimicrobial therapy within 7 days, antihistamines within 14 days, oral/topical glucocorticoids or cyclosporin within 28 days, and parenteral glucocorticoids, essential fatty acids or immunotherapy within 56 days of entry into the study. Dogs [minimum Canine Atopic Dermatitis Extent and Severity Index (CADESI) = 25] were randomly allocated to receive placebo, 100, 200 or 400 mg/kg Phytopica^TM daily for 12 weeks. Their CADESI was assessed every 4 weeks. A modified intention‐to‐treat population was analysed. The mean reductions in CADESI scores at the end of treatment compared to baseline were 4.4% (100 mg/kg; n = 30), 23.4% (200 mg/kg; n = 29, P < 0.01), 8.5% (400 mg/kg; n = 29) and 3.9% (placebo; n = 29). For more severely affected dogs (minimum CADESI ≥ 50 at baseline), there was significant reduction in mean CADESI score (29.3%, P = 0.038) only in the 200 mg/kg treatment group (n = 14). In conclusion, this study demonstrates that Phytopica^TM is an effective nonsteroidal treatment for canine AD. Funding: Phytopharm plc.     

Isolation and expression analysis of defensin gene and its promoter from Brassica juncea

Journal of Plant Diseases and Protection - The full-length pathogen-inducible plant defensin gene encoding 80 amino acid sequences of pathogen-related gene PR12 (Bjdefensin) was isolated from...     

The short-term effects of liming on organic carbon mineralisation in two acidic soils as affected by different rates and application depths of lime

Two acidic soils (initial pH, 4.6) with contrasting soil organic C (SOC) contents (11.5 and 40 g C kg^?1) were incubated with ¹³C-labelled lime (Ca¹³CO₃) at four different rates (nil, target pH 5, 5.8 and 6.5) and three application depths (0–10, 20–30 and 0–30 cm). We hypothesised that liming would stimulate SOC mineralisation by removing pH constraints on soil microbes and that the increase in mineralisation in limed soil would be greatest in the high-C soil and lowest when the lime was applied in the subsoil. While greater SOC mineralisation was observed during the first 3 days, likely due to lime-induced increases in SOC solubility, this effect was transient. In contrast, SOC mineralisation was lower in limed than in non-limed soils over the 87-day study, although only significant in the Tenosol (70 μg C g^?1 soil, 9.15%). We propose that the decrease in SOC mineralisation following liming in the low-C soil was due to increased microbial C-use efficiency, as soil microbial communities used less energy maintaining intracellular pH or community composition changed. A greater reduction in SOC mineralisation in the Tenosol for low rates of lime (0.3 and 0.5 g column^?1) or when the high lime rate (0.8 g column^?1) was mixed through the entire soil column without changes in microbial biomass C (MBC) could indicate a more pronounced stabilising effect of Ca²⁺ in the Tenosol than the Chromosol with higher clay content and pH buffer capacity. Our study suggests that liming to ameliorate soil acidity constraints on crop productivity may also help to reduce soil C mineralisation in some soils.     

Demonstration and validation of enhanced monitored natural recovery at a pesticide-contaminated sediment site

Purpose

Monitored natural recovery (MNR) combined with a thin-layer cap (TLC), often referred to as enhanced monitored natural recovery (EMNR), has the potential to accelerate and improve the effectiveness of MNR as a remedial strategy while minimizing widespread disturbance to the existing habitat. This study evaluated the effectiveness of a nominal 15-cm thin-layer sand cap as an EMNR remedial strategy to address sediments that were moderately contaminated with the chlorinated pesticide dichlorodiphenyltrichloroethane and its derivatives, collectively DDX.

Materials and methods

Physical, chemical, and biological measurements were conducted pre-remedy placement and 2, 14, and 25 months post-placement. Measurements were used to evaluate (1) TLC stability; (2) bottom-up mixing of the TLC; (3) advection through the TLC; (4) characteristics of newly deposited sediment atop the EMNR layer compared to pre-remedy surface sediment conditions; (5) changes in contaminant bioavailability; and (6) physical impacts to the benthic community.

Results and discussion

Significant reductions were observed from measurements conducted pre- and post-placement in surface sediment (84–97%), porewater (33–75%), and tissue concentrations (Lumbriculus variegatus deployed in situ) (72–82%). A 63 to 72% decrease in DDX depositional mass flux also was observed. Multiple lines of evidence indicated that the TLC material remained stable. Deposition of suspended material with low concentrations of DDX influenced low concentrations in the surface sediments. No adverse effects were observed on the benthic invertebrate community after TLC placement, and ecological metrics indicated increases in benthic community health, even in the short time period (2 months) following TLC placement.

Conclusions

This demonstration showed that EMNR can be effective at reducing biological exposure in surface sediments while minimizing short-term disturbances to benthic communities at sites where MNR is a remedy option, but natural deposition rates are inadequate to achieve cleanup goals within a reasonable timeframe.

     

<Emphasis Type="Italic">Pseudomonas</Emphasis> sp. strain AKM-P6 enhances tolerance of sorghum seedlings to elevated temperatures

A thermotolerant strain AKM-P6 of Pseudomonas sp. possessing plant growth-promoting properties was isolated from rhizosphere of pigeon pea grown under semiarid conditions in India. The effect of inoculation with AKM-P6 on survival and growth of sorghum seedlings at elevated temperatures (ET) was investigated under sterile and nonsterile soil conditions. Inoculation with strain AKM-P6 helped sorghum (var CSV-15) seedlings to survive and to grow at elevated temperatures (47–50°C day/30–33°C night) up to 15 days while uninoculated plants died by the fifth day of exposure to elevated temperature. Under sterile and nonsterile conditions, significantly higher root and shoot biomass were recorded in inoculated seedlings as compared to uninoculated control at ET, but this difference was nonsignificant at ambient temperature. Inoculation induced the biosynthesis of high-molecular weight proteins in leaves under elevated temperature, reduced membrane injury, and improved the levels of cellular metabolites like proline, chlorophyll, sugars, amino acids, and proteins. Scanning electron microscopy studies confirmed the colonization and establishment of the organism on the root surface. The 16SrDNA sequence of the strain AMK-P6 showed 97% homology with that of Pseudomonas aeruginosa in the existing database. The results indicate that Pseudomonas sp. strain AKM-P6 can enhance tolerance of sorghum seedlings to elevated temperatures by inducing physiological and biochemical changes in the plant.     

Alleviation of drought stress effects in sunflower seedlings by the exopolysaccharides producing <Emphasis Type="Italic">Pseudomonas putida</Emphasis> strain GAP-P45

Production of exopolysaccharides (EPS) can be used as a criteria for the isolation of stress tolerant microorganisms. In the present study, EPS-producing fluorescent pseudomonads were isolated from alfisols, vertisols, inseptisols, oxisols, and aridisols of different semiarid millet growing regions of India and were screened in vitro for drought tolerance in trypticase soy broth supplemented with different concentrations of polyethylene glycol (PEG6000). Out of the total 81 isolates, 26 could tolerate maximum level of stress (−0.73 MPa) and were monitored for the amount of EPS produced under maximum level of water stress. The strain GAP-P45, isolated from alfisol of sunflower rhizosphere, showed the highest level of EPS production under water stress conditions, was identified as Pseudomonas putida on the basis of 16S rDNA sequence analysis, and was used as seed treatment to study its effect in alleviating drought stress effects in sunflower seedlings. Inoculation of Pseudomonas sp. strain GAP-P45 increased the survival, plant biomass, and root adhering soil/root tissue ratio of sunflower seedlings subjected to drought stress. The inoculated bacteria could efficiently colonize the root adhering soil and rhizoplane and increase the percentage of stable soil aggregates. Scanning electron microscope studies showed the formation of biofilm of inoculated bacteria on the root surface and this, along with a better soil structure, might have protected the plants from the water stress.