Large-scale,multi-year,phenology modelling of forest insects in Pinus radiata plantations

Journal of Pest Science - Ecologically and economically harmful wood borers and bark beetles, which have the capacity to expand geographically through the international log trade, require...     

Demand and effect of potassium,magnesium, and calcium chlorides on hemolymph parameters,immune-related gene expression,and growth of Litopenaeus vannamei,Boone (1931) under biofloc technology

The ionic composition of culture water may be a more important limiting factor than the salinity itself and may lead to osmotic stress which may influence growth and survival of shrimp culture. The uptake rate and the effect of magnesium chloride (MgCl₂), calcium chloride (CaCl₂), and potassium chloride (KCl) salts in juveniles of whiteleg shrimp (Litopenaeus vannamei) cultured with biofloc technology (BFT) was evaluated for 62 days in seawater (30 practical salinity unity). Five treatments were analyzed in triplicate: T1; control (water exchange rate of 5% daily), T2; adding CaCl₂?+?MgCl₂?+?KCl, T3; adding MgCl₂?+?KCl, T4; adding CaCl₂?+?KCl, and T5; adding CaCl₂?+?MgCl₂. Mineral salts were added to water and the response of experimental parameters: physicochemical variables of water quality, osmotic pressure, total hemocyte count, glutathione peroxidase gene expression, superoxide dismutase, and zootechnical variables of the shrimp was assessed. The uptake of single chloride salts (CaCl₂, MgCl₂, and KCl) by shrimp varied as a function of the concentrations and the ratio of these three ions. Magnesium deficiencies in the culture medium increased CaCl₂ and KCl uptake without showing gene expression of SOD and GPx. The best survival rate was obtained by adding the three ions (T2) and the control (T1, water exchange of 5%). We concluded that L. vannamei can be maintained by the addition of essential chloride ions in BFT without water replacement.

     

Enzyme treatment for elimination of egg stickiness in tench (Tinca Tinca L.), European catfish (Silurus Glanis L.) and common carp (Cyprinus Carpio L.)

Enzyme treatment to eliminate egg stickiness in tench, European catfish and common carp was compared with standard methodology in an attempt to decrease time consuming under hatchery conditions. Eggs of tench and E. catfish were exposed to an alcalase enzyme MERCK EC 3.4.21.14 (0.6 AU g^?1) solution 3 min after egg fertilization for 2 min. The best enzyme concentration in tench and E. catfish was 10 and 20 ml l^?1 of enzyme, respectively. The eggs of c. carp were successfully destickiness with ALCALASE DX (2.5 AU g^?1) using two concentration of enzyme (2 ml l^?1 and 20 ml l^?1) from 8 to 20 min after fertilization.     

Characteristics of monoclonal antibodies against Piscirickettsia salmonis

A panel of 28 monoclonal antibodies against Piscirickettsia salmonis was produced using a purified fraction of the bacterium. To determine their specificity to the pathogen, the antibodies were assayed by ELISA and indirect immunofluorescence microscopy. Six monoclonal antibodies were selected based on their strong reaction against P. salmonis and absence of cross-reactivity with other common fish pathogens. Western blot analysis showed that the antibodies reacted to several antigens of P. salmonis . Immunofluorescence assays revealed that these antibodies reacted with the same specificity to different isolates of P. salmonis obtained from the south of Chile. This panel of monoclonal antibodies represents an important tool to develop simple, rapid, sensitive and highly specific methods for the detection of the pathogen and diagnosis of the disease.     

Weight–length relationships of 33 demersal fish species from Azores archipelago

Weight–length relationships are presented for 33 fish species of Azores archipelago. This work is the first reference on weight–length parameters of 16 species. Samples were collected between the years of 1999 and 2003 using longline at depths ranging from a few meters to 1200 m. The parameters of a and b of the equation W = aL^b were estimated. The b values of the species caught ranged from 2.701 for Lepidopus caudatus to 3.677 for Centroscymnus crepidater. Whenever possible, the b values for the species obtained both in this study and some of the previously reported in the Portuguese waters were compared.     

A system for model-based biomass estimation of larvae in intensive cod larvicultures

High and unpredictable mortality rates are observed in the larval rearing of cod (Gadus morhua). As a means of addressing this problem, we present a model-based estimator system which can be used to indirectly measure the larval density through monitoring the live food dynamics and larval growth. The estimator has been evaluated in a conceptual context using a preliminary model formulation, and the observability of the process has been investigated. It was found that the two parameters, live food dynamics and larval growth, contain enough information for the larval density to be estimated under noisy conditions, given the correct model. When the system is applied practically, the estimation error will depend on the measurement and model accuracy; this is especially true with respect to the predictability of the feed intake rate of the fish.     

Growth performance of crossbred naked neck and normal feathered laying hens kept in tropical villages

1. Two experiments were conducted to develop naked neck (Na/na) and normal feathered (na/na) crossbreds and compare their growth performance, linear body measurements and carcass characteristics in the first and second filial generations.

2. In the first experiment, 4 indigenous naked neck males (Na/na) were mated to 36 Lohmann commercial females (na/na) in a ratio of 1:9. The two genotypes (Na/na, na/na) were allocated randomly according to batches of hatch, sire lines and sex to three different villages.

3. In the second experiment, 10 males and 100 females of F₁ Na/na birds were selected and mated inter se in a ratio of 1:10. The three genotypes (Na/Na, Na/na and na/na) were compared in a randomised complete block design experiment, with the three villages, hatch and sex as blocks and the three genotypes as treatments. F₁ Na/na birds had significantly higher (P < 0.05) feed conversion ratio, body weight, body weight gain, linear body measurements, survivability and carcass yield than their na/na counterparts.

4. In the F₂ generation, Na/Na and Na/na birds had significantly higher (P < 0.05) feed conversion ratio, body weight, body weight gain, linear body measurements, survivability and carcass yield compared to their na/na counterparts.

5. The birds showing the naked neck phenotype appeared to show superior performance compared to normal feathered birds and could be exploited for potential utilisation in local poultry production.     

Use of a staphylococcal vaccine to reduce prevalence of mastitis and lower somatic cell counts in a registered Saanen dairy goat herd

This investigation evaluated the efficacy of a bacterin in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a dairy goat herd. Does were vaccinated or left as controls, and the levels of mastitis and SCC monitored over 18 months. Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI). The infection rate was 1.64 IMI/doe among vaccinates, which tended to be lower (P < 0.12) than controls (2.67 IMI/doe). The spontaneous cure rate of IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than controls (0.6 cures/doe; P < 0.043). Average SCC of milk samples from vaccinates tended to be lower than that of controls (1274 × 10³/ml vs. 1529 × 10³/ml, respectively) (P < 0.10). Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats.