Reproduction of Penaeus kerathurus using eyestalk ablation

In a preliminary experiment on the induction of sexual maturity in Penaeus kerathurus by unilateral eyestalk ablation, spawning was obtained in 94% of the females treated. The time necessary to reach the spawning stage appeared to be closely related to the stage of natural physiological development of the gonads and the length of the photoperiod, the period between ablation and spawning decreasing from 69 days for females treated in November to about 10 days for females treated at the beginning of their natural reproductive period in May/June. Spawning after treatment was repeated up to eight times, sometimes at intervals of less than 10 days, without showing a decrease in the amount of fertile spawn. The mean number of fertile eggs per spawn was 78.400, which is not significantly different from the corresponding mean obtained previously after thermal stimulation of almost mature breeders; the hatching percentage, 67%, was also similar. Often only the anterior and median lobes of the ovaries are included in the spawning process. The discharged spawn is nearly always completely free of matrix material. It is anticipated that induction by eyestalk ablation could allow a considerable extension of the growing season and of the area suitable for culture.     

ARTIFICIAL REPRODUCTION OF Penaeus japonicus BATE AS A BASIS FOR THE MASS PRODUCTION OF EGGS AND LARVAE1

Penaeus japonicus Bate is absent on the Italian coasts, but it is considered a very promising species for national aquaculture. To develop the shrimp-culture on a commercial basis, a convenient method for producing eggs and larvae of Penaeus japonicus was studied. A stock of 156 females, age class 1+ and F₃, underwent unilateral eyestalk ablation and they were stocked with males in three plastic tanks (bottom area 14 m²) at a density of 25 individuals/m² and a sex ratio of 1:1. Conditions of environment and management consisted of: temperature 21±3°C; natural light and photoperiod; total exchange of sea water every day; feeding on mussels. A month after eyestalk ablation the females were inspected every 7–10 days; mature females were transferred to the spawning tanks. Females with well developed gonads averaged 25.0% of the population of females at every inspection; 51.3% of spawners were impregnated with spermatophores; others were inseminated artificially by the method of introducing spermatophores into the thelycum. In six inspections (carried out during a period of 89 days), 3,028,525 eggs were released; a female released 17,500 eggs on the average (maximum was 123,000 eggs, minimum 4,340). The mean rate of fertilized eggs was 52.7%—67.7% from naturally inseminated females and 7.5% from the artificially inseminated ones. The mean hatching rate was 30.9%—40.1% from natural insemination and 3.3% from artificial insemination. Total amount of viable nauplii was 820,550.     

IgG antibodies from dourine infected horses identify a distinctive Trypanosoma equiperdum antigenic pattern of low molecular weight molecules

Diagnosis and control of dourine is strongly based on serological evidence, but knowledge of the humoral response of horses during infection is limited. In this study we developed a chemiluminescent immunoblotting (cIB) assay to characterise the Trypanosoma equiperdum antigen pattern recognised by IgGs from naturally or experimentally dourine-infected horses and analyse the kinetics of IgG humoral response following the infection. One compounding factor is that sera from uninfected animals often cross-react with T. equiperdum antigens. Development of the cIB assay was based on the hypothesis that serum IgGs from healthy and infected animals recognise different T. equiperdum antigen patterns. We used sera from 8 naturally infected horses which had recovered from Italian outbreaks and 2 experimentally infected mares. In addition, sera from 10 healthy control animals, eight of which were CFT positive but IFA negative for dourine, were collected from disease free regions. Sera were compared by the complement fixation test (CFT), indirect immune fluorescence (IFA) and the cIB assay.cIB analysis revealed that IgGs from infected horses, in contrast to IgGs from healhty horses, specifically recognise a T. equiperdum antigenic profile with low molecular weight bands ranging between 16 and 35 kDa. A time course experiment indicated that IgGs specific for the 16–35 kDa parasite protein fraction appear 17 days post-infection. The cIB assay confirmed all ten infected animals as positive and all controls as negative. This study demonstrated that analysis of IgGs by cIB can provide clear confirmation of trypanosome infection in horses, suggesting that this technique can be applied as a confirmatory serological test for dourine infection.     

Factors affecting the contents of iridoid oleuropein in olive leaves (Olea europaea L.)

In this study, for the first time, the impact of the genetic factor on the contents of oleuropein in olive leaves was not only evaluated but the influence exerted by the color/age of leaves (green, green-yellowish, and yellow) and the collecting period (spring or autumn) was also evaluated. A repetitive high-resolution gas chromatographic quantitation method and an accurate high-performance liquid chromatographic method were developed. These analytical methods gave results showing a highly linear relationship. Samples of olive leaves were taken from seven major Italian olive cultivars, such as Dritta, Leccino, Caroleo, Coratina, Castiglionese, Nebbio, and Grossa di Cassano. Such a vegetal raw material could actually be exploited for recovering oleuropein, considered to be a high-added value molecule. This could be converted into hydrxytyrosol, a compound known to possess strong bioactive properties. Olive leaves showed considerable contents of oleuropein, which with some cultivars were even higher with respect to those present in the corresponding olive fruits (reported in the literature). The amounts of oleuropein in the collected leaves were markedly modified by the color/age and genetic factors, whereas meaningless variations were ascribable to the quantitation method and the collecting period factors. Various chemometrics, applied to the obtained analytical data, appeared to be effective in discriminating the samples on the basis of the above-examined experimental factors, thus confirming how these should be taken into account in future industrial recovery of oleuropein from olive leaves.     

Spatially Variable Rate Herbicide Application on Durum Wheat in Sicily

Using the conventional farming system, durum wheat requires high rates of herbicide spraying. Herbicide residues can cause pollution of soil and ground water and, therefore, of the entire environment.In order to minimise the environmental impact of herbicides, a home-made system for spatially variable rate crop input application was designed and developed. This system consists of a differential global positioning system (DGPS), a portable computer, specifically developed software and a device for applying rates proportionally related to the machine forward speed.Tests of spatially variable rate herbicide application were carried out in inland Sicily, on a field of 8.4 ha (where a 3-yr crop rotation of broad bean/vetch, durum wheat and durum wheat was practised), using a sprayer modified for applying variable rates and equipped with the above-mentioned system.The results are promising. The spatially variable rate herbicide application allowed an almost even grain yield over the entire field and a saving of 29% of herbicides with respect to the amounts normally used with the conventional farming system.     

Development and validation of a competitive ELISA kit for the serological diagnosis of ovine, caprine and bovine brucellosis

A competitive ELISA (Brucella-Ab c-ELISA) was standardized and validated for the detection of Brucella antibodies in cattle, sheep and goat sera using a monoclonal antibody (MAb 4B5A) produced against Brucella melitensis biotype 2. The specificity and sensitivity of the assay were 100% to a 67.5% cut-off point (B/Bo%). When compared with an indirect ELISA, the Brucella-Ab c-ELISA did not demonstrate cross-reactions when testing positive sera for antibodies to some Enterobacteriaceae. A comparison was made between the Brucella-Ab c-ELISA and the complement fixation and Rose Bengal tests. Results demonstrated that the Brucella-Ab c-ELISA is a valuable tool for the serological diagnosis of bovine and ovine/caprine brucellosis.