Biofloc technology (BFT) provides an additional feed source for aquatic organisms through the conversion of waste in microbial flocs. Because of this, the suitable protein level in a diet for animals in this system could be different from those in conventional systems. Our objective was to determine the suitable protein level in the diet of Nile tilapia juveniles reared with BFT. Two experiments were carried out with tilapia weighing~10 g (first experiment) and about 50 g (second experiment) during 61 and 98 days respectively. Five crude protein (CP) levels (within 17% and 33%) were tested. The increment of CP resulted in a reduction in dissolved oxygen, pH, alkalinity and an increase in dissolved phosphorus, total suspended solids and total ammonium nitrogen. The crude protein level had a significant effect (p < 0.05) on animal performance. The linear response plateau model was the best fit for the final weight and weight gain data in the two growth phases. In conclusion, tilapia juveniles of 10-60 g and 60-230 g in biofloc can be fed on diets with 28% of CP (26% of digestible protein) and 22% CP (20% of digestible protein) respectively. K E Y W O R D Sbiofloc technology, growth performance, Nile tilapia, nutrition

No abstract

Feeding strategies of tilapia (initial average weight: 32 g) cultivated with Biofloc technology (BFT) (carbon source: sugarcane, C:N ratio: 6:1) for 56 days were studied. A 4 × 3 factorial experimental design was used with four feeding frequencies (one, two, three and four times a day) and three feeding rates (50%, 75% and 100% consumption in relation to apparent satiety), with four replicates. Lower levels of dissolved oxygen, protein retention rate and body protein content were found in fish fed once a day. The reduction in feeding rate resulted in lower average final weight and reduced growth but promoted a decrease in the concentration of total ammonia nitrogen, solids, hepatosomatic index and body lipids. We found better efficiency of protein utilization at 75% feed. The nutritional value of the floc was not affected by the feeding frequency, and the feeding rate reduction from 100% to 75% did not alter the protein content of the floc. Thus, twice‐daily feeding frequency is sufficient for Nile tilapia fingerlings reared in BFT. Although the feeding rate of 100% satiety has led to better performance, it may not be the best option in BFT due to higher feed conversion and reduction of water quality.

Cheilitis glandularis (CG) is a rare inflammatory disease of unknown etiology that affects the minor salivary glands predominantly in the lower lip. In this article, we report the case of an 18‐year‐old black woman who presented with a deep suppurative type of CG in both lips. In addition, we performed a systematic literature review in five databases (PubMed, Scopus, Web of Science, Ovid, and Embase) to identify CG case reports or case series. A total of 360 references were retrieved in the electronic databases. Thirty‐four articles met the inclusion criteria, and six were retrieved through manual search, totaling 40 articles included in the systematic review. Thirty‐nine (68.4%) cases occurred in male individuals and 18 (31.6%) in female individuals. The mean age of affected individuals was 40.9 years. Different clinical manifestations ranging from no symptoms to discomfort, pain, swelling, erythema, eversion of the lip, dilated ductal openings, ulcers, and crust have been reported. Among the included CG cases, 41 affected exclusively the lower lip (71.9%). In four cases, the CG only affected the upper lip (7.0%). In 12 cases, the lesion affected both the lower and upper lips (21.1%). Different treatment modalities were adopted in the management of CG. Although the surgical treatment was indicated (42.1%), the conservative treatment with topical medications, as in the present case, resulted in resolution in 21.0% of cases.

Arsenic is an ametal ubiquitous in nature and known by its high toxicity. Many studies have tried to elucidate the arsenic metabolism in the cell and its impact to plants, animals and human health. In aqueous phase, inorganic arsenic is more common and its oxidation state (As III and As V) depends on physical and chemical environmental conditions. The aim of this study was to evaluate toxicity of arsenic to Daphnia similis and Ceriodaphnia silvestrii, isolated and associated with iron. The results showed differences in toxicity of As III and As V to both species. Effective concentration (EC50) mean values were 0.45 mg L -1 (As III) and 0.54 mg L -1 (As V) for D. similis, and 0.44 mg L -1 (As III) and 0.69 mg L -1 (As V) for C. ), showing synergistic effect of these substances.