Effect of different total suspended solids levels on a Litopenaeus vannamei (Boone, 1931) BFT culture system during biofloc formation

In a Biofloc Technology System (BFT), there is constant biofloc formation and suspended solids accumulation, leading to effects on water quality parameters that may affect the growth performance of cultured shrimp. This study aimed to analyse during biofloc formation the effect of different total suspended solids (TSS) levels on water quality and the growth performance of Litopenaeus vannamei shrimp in a BFT system. A 42‐day trial was conducted with treatments of three ranges of TSS: 100–300 mg L^?1 as low (TL), 300–600 as medium (TM) and 600–1000 as high (TH). The initial concentrations of 100 (TL), 300 (TM) and 600 mg L^?1 (TH) were achieved by fertilization before starting the experiment. Litopenaeus  vannamei juveniles with an average weight of 4.54 ± 1.19 g were stocked at a density of 372 shrimp m^?3. Physical and chemical water parameters and shrimp growth performance were analysed. After 6 weeks, TSS mean concentrations were 306.37, 532.43 and 745.2 mg L^?1 for, respectively, TL, TM and TH treatments. Significant differences (P < 0.05) were observed in TSS, settleable solids, pH, alkalinity and nitrite, especially between the TL and TH treatments. Similarly, differences (P < 0.05) were observed in the growth performance parameters, specifically final weight, survival, feed conversion and productivity. The water quality parameters at lower range of total suspended solids concentration (TL) treatment resulted in a better performance of L. vannamei in the BFT system. The maintenance at range of 100–300 mg L^?1 TSS is thus important to the success of shrimp culture.     

Ammonium release via dissolution and biological mineralization of food pellets used in salmon farming

We studied the input of ammonium coming from the dissolution of food pellets commonly used in salmon farming as well as its potential for mineralization via ammonification and ammonium oxidation by natural bacterioplankton communities. Through experiments in central and southern Chile, we evaluated the potential for photo‐ and bio‐ammonification of food pellets in surface and subsurface waters (30 m depth) using irradiated (PAR + UV; IPS) and non‐irradiated dissolved‐pellet solutions (NIPS). Ammonium release was observed in both IPS and NIPS treatments and occurred at short time scales (<2 hr). Experiments in southern Chile during late winter showed high rates of pellet ammonium release in surface waters (up to 3.8 µmol L^?1 min^?1) compared with deeper samples (30 m depth). In contrast, in spring higher rates were observed at 30 m depth and reached up to 45 µmol L^?1 min^?1 while in surface waters they accounted for 9 µmol L^?1 min^?1. Ammonium oxidizing bacteria and archaea showed seasonal variability, but archaea were detected in all experiments reaching high potential activity, based in RT‐qPCR of functional genes expression copy numbers, in IPS treatments during the winter season in Chiloé. Overall, our results indicate that food pellets can be a source of ammonium, which can exceed by two orders of magnitude the average natural concentrations commonly found in the euphotic layer in coastal environments. The ammonium enrichment from dissolved pellet solutions was rapidly consumed by microbial communities including nitrifying assemblages. This has implications for the evaluation of aquaculture nutrient input and its recycling in the water column in areas highly impacted by climate change and aquaculture pressure.     

Genetic progress of oats in Italy

The genetic gain of oats in Italy over the past 40 years was evaluated using 14 cultivars belonging to three different groups: (i) five cultivars derived from local populations at the beginning of the oat breeding in Italy; (ii) four foreign cultivars, introduced in Italy in the 1980s; (iii) five modern cultivars, selected through specific breeding programmes. The genotypes were tested for 2 years in three locations characterised by different climatic conditions and agricultural practices; furthermore in one location in Southern Italy, irrigated and rainfed plots were compared. Genetic gain was estimated equal to 3.6 g m⁻² y⁻¹ based on eight environments. The performance of the most recent cultivars was high under both irrigated and rainfed conditions, showing a good adaptation of these genotypes to both fertile and drought prone environments. Finally, yield increase in oats was found to be negatively correlated with plant height and positively correlated with test weight and seed weight.     

MICRONODULAR ULTRASOUND LESIONS IN THE COLONIC SUBMUCOSA OF 42 DOGS AND 14 CATS

Micronodular ultrasound lesions have been detected in the colonic submucosa of dogs and cats at our hospital. The lesions had rounded/oval shapes, measured 1–3 mm in size, and exhibited a hypo/anechoic ultrasonographic pattern. To our knowledge, these lesions have not been previously reported in human or veterinary patients. The purpose of this retrospective study was to determine whether micronodular lesions were associated with other abdominal ultrasound abnormalities or clinical findings. Medical records of dogs and cats with sonographic reports describing micronodular lesions within the colonic submucosa were reviewed. Concurrent ultrasonographic abnormalities were recorded and compared with clinical sidgns and follow‐up data. A total of 42 dogs and 14 cats met inclusion criteria. Concurrent sonographic abnormalities included the following: increased colon wall thickness (12.5%); small bowel wall thickening, altered layering, and/or hyperechoic mucosa (45%); abdominal effusion (29%); caudal mesenteric lymphadenopathy (46%); mesenteric lymphadenopathy (27%); and pericolic peritoneal fat reactivity (9%). Fifty of 56 animals presented with diarrhea. Twenty‐seven cases had clinical signs of colitis and ultrasonographic lesions were limited to the colonic submucosa. In nine cases, follow‐up examination at 6–8 weeks showed resolution of clinical and ultrasonographic signs. Ultrasonographic and clinical examinations in 17 patients at 12–18 months and in 20 patients at 18–30 months from initial diagnosis showed resolution of submucosal lesions and clinical signs of enteropathy. The authors propose that micronodular submucosal ultrasound lesions may represent reactive intraparietal lymphoid follicles and may be indicators of colonic inflammatory diseases in dogs and cats.     

Bioremediation of a Soil Industrially Contaminated by Wood Preservatives��Degradation of Polycyclic Aromatic Hydrocarbons and Monitoring of Coupled Arsenic Translocation

Two commercially available aerobic bioremediation methods (Daramend® and BioSan) were utilized to study the aerobic biodegradation of polycyclic aromatic hydrocarbons (PAH) and the effect of the simultaneously present arsenic. The soil was collected at an old wood preservation site, and the initial PAH₁₆-concentration was 46 mg/kg, with mainly high molecular weight congeners. The As concentration was 105 mg/kg with low availability as assessed with sequential extraction. To enhance the availability of PAH, the effect of a nonionic surfactant was evaluated. Degradation of both low and high molecular weight PAH was observed; however, after 30 weeks, the degradation was generally low and no treatment was significantly better than the others. The treatments had, on the other hand, an effect on As remobilization, with increased As concentration in the available fraction after treatment. This may be due to both the microbial activity and the presence of anoxic microsites in the soil. The overall efficiency of the biological treatment was further evaluated using the standardized ecotoxicity test utilizing Vibrio fischeri (Microtox®). The toxicity test demonstrated that the bioremediation led to an increase in toxicity, especially in treatments receiving surfactant. The surfactant implied an increase in contaminant availability but also a decrease in surface tension, which might have contributed to the overall toxicity increase.