This study evaluated the potential for the replacement of fishmeal (FM) by biofloc meal (BM) in the diet of Litopenaeus vannamei postlarvae. Four isonitrogenous (437.42 g kg À1 ) and isocaloric (19.84 kJ g À1 ) diets were formulated, in which FM was replaced with BM at 0% (T0), 7.5% (T7.5), 15% (T15) and 30% (T30). A commercial diet (CD) was used as reference. The study was conducted over 42 days in 50 L tanks connected to a water recirculation system. All tanks were stocked with three postlarvae (initial weight 0.0023 g) per litre. Shrimp survival, weight gain (WG), final weight (FW), specific growth rate (SGR) and protein efficiency ratio (PER) were measured. Survival rates were high (>91.1%) in all treatments. As the T30 treatment returned a significantly (<0.05) better performance in WG, FW, SGR and PER than all other treatments, partial replacement of FM with BM does not appear to affect productivity. In fact, a regression analysis indicated that a FM to BM replacement level of over 20% may actually improve shrimp growth. In addition to providing a cost-effective alternative ingredient for L. vannamei postlarvae diets, the production of meal also represents a more sustainable way of disposing of the excess of biofloc produced by BFT systems.

This study aimed to evaluate the effect of the gradual replacement of fishmeal with fish protein hydrolysate (FPH) and biofloc flour (BF) in the diets of white shrimp Litopenaeus vannamei postlarvae (2 mg). Five diets (420 g kg À1 of crude protein) were formulated, and these replaced 0 (control), 10, 20, 30 and 40% (T0, T10, T20, T30 and T40, respectively) of the fishmeal. A commercial diet was used as an external control. The alternative ingredients FPH and BF were added at a ratio of 1 : 1. After 42 days, the shrimp survival was higher than 99% in all the treatment groups. A regression test indicated that the ideal fishmeal substitution level to obtain optimal zootechnical parameters (final weight, weight gain and protein efficiency) is between 15.16 and 16.5%. In this study, we demonstrated that BF and FPH are potential ingredients that can be used to replace fishmeal in L. vannamei postlarvae diets.

The semiarid northeast of Brazil contains a unique biome known as caatinga, with a maximum temperature of 40 ºC and a relativity humidity of 56%. The caatinga is characterized by a variety of plants, including Cereus jamacaru Dc (mandacaru), Poincianella microphylla Mart. ex G. Don (catingueira), Pilosocereus gounellei FAC Weber (xique-xique) and Mimosa tenuiflora (Willd.) Poir (jurema preta). Sheep and goat industries are economically strong in that region, despite the fact that caseous lymphadenitis is highly prevalent. The aim of the present study was to assess the survival and biofilm production of Corynebacterium pseudotuberculosis isolates in the environment and under controlled temperatures (28°C, 37°C and 42°C) under different surfaces (plants, soil, wood, wire and thorns). In addition, we investigated the effects of applying the disinfectants chlorhexidine, hypochlorite and quaternary ammonia in soil, tiles, wood and vegetation cover. Four strains of C. pseudotuberculosis were selected (two from goats and two from sheep) for inoculation according to their in vitro biofilm production. Adherence to microplates was used to assess the biofilm-forming ability of the bacteria. Lower survival rates were observed when isolates of C. pseudotuberculosis were subjected to a temperature of 42°C. In terms of caatinga biome plants, contamination of jurema-preta plants resulted in the lowest survival rates. The disinfectant quaternary ammonia promoted a lower inoculum survival in all surfaces. The disinfectants and the higher temperature contributed to the reduction of biofilm production in isolates of C. pseudotuberculosis. knowledge of these patterns is important for the establishment of disease control measures, given the questionable efficacy of the treatment and the immuno-prophylaxis of caseous lymphadenitis.