Embryonic development and influence of egg density on early veliger larvae and effects of dietary microalgae on growth of brown mussel Perna perna (L. 1758) larvae under laboratory conditions

The effect of egg density on embryonic development and larval quality as well as the lipid and fatty acid contents (eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA) of cultured microalgae fed to Perna perna larvae was studied under controlled conditions to provide information needed for development of an experimental hatchery. Embryonic development followed the common sequence exhibited by other bivalves. d-larva stage was attained 40–44 h post-fertilisation at 21 ± 1 °C. The umbo-stage was reached in 11 days, and pediveliger larvae were observed 26 days post-fertilisation. Low egg density (range 20–100 eggs cm^?2) produced high proportions of normal d-larvae. Larval development showed two growth phases: 1st—the mixotrophic stage and 2nd—the exotrophic stage where the composition of diets had significant effects on larval growth with higher rates in larvae fed with the mixed microalgae (Isochrysis galbana + Chaetoceros calcitrans, I. galbana + Phaeodactylum tricornutum and I. galbana + Skeletonema costatum) in comparison with the monospecific diet (I. galbana). Fatty acid analysis showed that larval growth and survival were strongly influenced by proportions of dietary DHA and EPA. These results indicate that DHA and EPA are the key factors in determining larval performance, considerably more than the total amount of other fatty acids.     

Availability of triazine herbicides in aged soils amended with olive oil mill waste

Amendments are frequently added to agricultural soils to increase organic matter content. In this study, we examined the influence of alperujo, an olive oil mill waste, on the availability of two triazine herbicides, terbuthylazine and atrazine, in two different sandy soils, one from Sevilla, Spain, and the other from Minnesota. The effect of aging on herbicide sorption and bioavailability was also studied. Soils were amended with alperujo at a rate of 3-5% (w:w) in laboratory studies. Apparent sorption coefficients for the triazine herbicides were calculated as the ratio of the concentrations of each herbicide sequentially extracted with water, followed by aqueous methanol, at each sampling time. These data showed greater sorption of terbuthylazine and atrazine in amended soils as compared to nonamended soils, and an increase in the amount of herbicide sorbed with increasing aging time in nonamended soils. The triazine-mineralizing bacterium Pseudomonas sp. strain ADP was used to characterize triazine bioavailability. Less mineralization of the herbicides by Pseudomonas sp. strain ADP was observed in soils amended with alperujo, as compared to the unamended soils, and, despite the increase in sorption with aging in unamended soils, herbicide mineralization also increased in this case. This has been attributed to Pseudomonas sp. strain ADP first using alperujo as a more readily available source of N as compared to the parent triazines. In summary, addition of alperujo to the soils studied was shown to increase triazine herbicides sorption and hence to reduce its availability and potential to leach.     

Effects of calving season on the voluntary waiting period and reproductive performance of Holstein cows in the tropical savannah

The effects of calving season [rainy (RS) and dry (DS)] on the voluntary waiting period (VWP) of 58 Holstein cows raised in the tropical savannah were investigated using data of temperature humidity index (THI), total antioxidant status (TAS), respiratory rate (RR), rectal temperature (RT), glucose, total cholesterol (TC), triglycerides (TG), velocity of uterine regression, and subsequent reproductive performance. Blood samples and clinical data were taken once every week, from calving until the sixth postpartum week. Reproductive data were collected until 180 days postpartum. THI differed between seasons (P < 0.05], as well as TAS (P < 0.001), RR (P < 0.001), RT (P < 0.01), glucose (P < 0.001), TC, and TG (P < 0.05), with higher values in RS. Although the velocity of uterine regression showed to be slower (P < 0.001) during RS, no differences were present regarding uterine health. Days open increased in RS (P < 0.001), but the number of services/conception was similar (P = 0.33). The results suggested cows under heat stress during the rainy season in the tropical savannah are more susceptible to a decline in the reproductive performance due to oxidative, metabolic, and uterine health problems.     

Feeding preference of Thaumastocoris peregrinus on several Eucalyptus species and the relationship with the profile of terpenes in their essential oils

The feeding preference by Thaumastocoris peregrinus, Carpintero and Dellapé (Heteroptera: Thaumastocoridae) on different Eucalyptus species was evaluated through choice tests in a paired comparisons design. Twenty individuals per combination were tested over a 48 h period, and each one was offered leaves of two species at a time, in all possible combinations. Preference was determined by counting the number of insect excrements on each plant as a proxy for effective feeding, and then ranked through a paired comparison matrix. A linearity index was calculated to test for hierarchy preferences and, after that, a cardinal index (David’s score) was calculated to assign a preference value for each species. The essential oils were extracted from leaves of each Eucalyptus species, and their chemical composition determined through GC-MS. The results show a significant and strictly linear feeding preference ranking between the species tested. The order of preference between species was E. viminalis > E. grandis > E. tereticornis > E. dunnii > E. maidenii > E. globulus. The qualitative and quantitative chemical compositions of the essential oils of these Eucalyptus species differed. A significant correlation was found between the feeding preferences and the concentrations of 1,8-cineole as a repellent and p-cymene as a feeding stimulant. These results underline the importance of selecting the right Eucalyptus species in areas infested by T. peregrinus.     

Cutaneous and gastrointestinal pythiosis in a dog in Brazil

The oomycete Pythium insidiosum is the pathogenic cause of pythiosis, a life-threatening disease that affects several animal species. Canines are the second most affected species, and the disease is characterized by the development of cutaneous and gastrointestinal lesions. While concomitant cutaneous and gastrointestinal lesions are rarely found in the same animal, this report documents a case of concurrent cutaneous and gastrointestinal pythiosis in an 18-month-old female Labrador. This dog had an ulcerative cutaneous lesion on the right thoracic region for 12 months that was unresponsive to itraconazole and terbinafine therapy. Two months prior to death and concurrent with the cutaneous lesion, the dog became anorexic with frequent vomiting and bloody stools. At necropsy, a cutaneous lesion that extended subcutaneously into the intercostal muscles was observed. Additionally, the large intestine contained two lesions that caused luminal narrowing. Organs were collected, routinely processed and stained using hematoxylin and eosin and Gomori methenamine silver. Histological examination of the lesions in the large intestine and on the skin revealed areas of necrosis surrounded by a pyogranulomatous infiltrate. Occasionally, black, septate, branching hyphae were detected following staining with Gomori methenamine silver. The diagnosis of pythiosis was confirmed using immunohistochemical methods. This report describes the occurrence of concomitant gastrointestinal and cutaneous lesions in a dog and highlights the therapeutic difficulties encountered with this disease.     

Insecticidal activity of chemical constituents from Aristolochia pubescens against Anticarsia gemmatalis larvae

Acetone and ethanol extracts of the tubercula and several compounds isolated from Aristolochia pubescens (Willd) were bioassayed on velvetbean caterpillars, Anticarsia gemmatalis (Hübner), for evaluation of the insecticidal activities. Of the extracts subjected to bioassay, the acetone extract showed the highest activity. (-)-Cubebin did not show activity against soybean caterpillars, whereas aristolochic acid and ent-kaur-15-en-17-ol increased the larval period. These compounds, and (+)-eudesmin and (+)-sesamin, reduced the viability of this period, giving rise to malformed adults. These extracts and compounds are therefore potential botanical insecticide agents for the control of velvetbean caterpillars in soybean crops.     

Attraction of mosquitoes to domestic cats in a heartworm enzootic region

Heartworm disease is caused by a mosquito-borne parasite that can affect many different mammalian species and has worldwide distribution. The agent, Dirofilaria immitis (Leidy 1856), infect mainly dogs but feline infection have been frequently reported in the last decade. Feline heartworm infection is difficult to detect, therefore, low reported prevalence could reflect true low prevalence or poor diagnostic efficiency. As mosquitoes are known to be attracted differently by different mammalian species, mosquitoes were collected from both a cattery and a contiguous home located in a canine heartworm enzootic area in Niterói, state of Rio de Janeiro, Brazil. For 14 months, mosquitoes were collected weekly for genus identification, speciation when possible, and for individual blood meal identification. Culex species mosquitoes were the most captured and those most frequently found with feline blood meal, followed by Aedes species that, although captured in lower numbers, also fed on feline blood. While Culex species mosquitoes have been reported as potential secondary heartworm vectors for dogs and primary vectors for cats, the present results suggest that Aedes species mosquitoes may also be involved in feline heartworm transmission in a larger proportion than previously thought.