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Roberta Cavalcanti Nery Camila Barros Costa Flvio Rodrigues Roberta Soares Ranilson de Souza Bezerra Silvio Peixoto 《Aquaculture Nutrition》2019,25(3):577-584
The present study evaluated the effects of feeding frequency during the grow‐out phase of Litopenaeus vannameiin biofloc system. The experiment comprised of four treatments with three replicates each, corresponding to the following feeding frequencies: one (8:00 a.m.), two (8:00 a.m. and 4:00 p.m.), three (8:00 a.m., 12:00 p.m. and 4:00 p.m.) and four times a day (8:00 a.m., 10:00 a.m., 12:00 p.m. and 4:00 p.m.). Zootechnical performance and digestive enzyme activity were monitored for 63 days. At the end of the experiment, the highest survival rates were found for the individuals fed three and four times a day. Wet weight gain (6.63 g) and specific growth rate (3.46% per day) of the individuals fed three times a day were significantly higher compared to animals fed one and four times a day, but did not differ significantly to the group fed twice a day (6.15 g and 3.46% per day, respectively). The digestive enzyme activities were not affected by the feeding frequency, but negative correlations were found between these activities and shrimp weight. It is recommended that L. vannamei should be fed three times a day during the grow‐out phase in a biofloc system under the conditions used in this study. 相似文献
958.
Cetacean occurrence,habitat preferences and potential for cetacean–fishery interactions in Iberian Atlantic waters: results from cooperative research involving local stakeholders
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Sabine Goetz Fiona L. Read Marisa Ferreira Julio Martínez Portela Maria Begoña Santos José Vingada Ursula Siebert Ana Marçalo Jorge Santos Hélder Araújo Silvia Monteiro Mara Caldas Marcos Riera Graham J. Pierce 《水产资源保护:海洋与淡水生态系统》2015,25(1):138-154
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Lise M. H. Ferreira Gabriele Lara Wilson Wasielesky Jr. Paulo Cesar Abreu 《Aquaculture International》2016,24(4):921-930
The aim of this study was to evaluate the addition of artificial substrates in biofloc technology systems that are used for the intensive production of Litopenaeus vannamei. The experiment lasted 35 days. Tanks each with a useful volume of 800 L were filled with water containing bioflocs (25 % of the total volume) and filtered seawater. Three treatments with three replicates each were compared: (1) Ctrl (control), i.e., without the addition of artificial substrate, (2) 200 and (3) 400, with added artificial substrate equivalent to 200 and 400 % of the lateral area of the tanks, respectively. The shrimp with initial weight of 0.40 ± 0.15 g were stocked at a density of 300 shrimp/m2. Feed (Guabi/38 Active, Brazil) was supplied two times per day. The water quality parameters were suitable for the production of L. vannamei. The settleable solids (SS) were higher in the Ctrl treatment (82.1 ± 19 mL L?1) and differed statistically from the 200 and 400 treatments that presented average SS values below 10 mL L?1. The reuse of water with bioflocs accelerated nitrification in the tanks, and no significant differences were shown between tanks. The presence of biofilm did not interfere with ammonium or nitrite levels, but it did serve as a food source that optimized shrimp performance, as shown by higher final weights. More studies are needed to evaluate the circulation and mixing intensity effects of the substrates on water throughout the production cycle. 相似文献
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Hamilton Hisano José Luiz Pilecco Jorge Antônio Ferreira de Lara 《Aquaculture International》2016,24(4):1049-1060
Corn gluten meal (CGM) has a high protein content and absence of antinutrients. However, it has high levels of carotenoids that can cause a yellowing of fish fillets and impair further commercialisation. Graded levels of CGM were incorporated in pacu diets to replace soybean meal (SM) protein. The experimental diets were formulated to be isonitrogenous (220 g kg?1 digestible protein) and isoenergetic (13.4 MJ kg?1 digestible energy) with 0, 25, 50, 75, and 100 % replacement of SM protein by CGM protein over a 60-day period. One hundred fish (32.79 ± 3.43 g) were randomly distributed in 20 experimental cages (70 L) placed within five (1000 L) aquaria with continuous water renewal. The experimental design was completely randomised with five treatments and four replicates. A quadratic effect (P < 0.05) was observed for fillet and carcass yields, feed conversion ratio, weight gain, and specific growth rate, with the optimum values for replacement of SM protein by CGM protein estimated as 21.95, 29.13, 30.94, 37.71, and 38.75 %, respectively. There were no differences (P > 0.05) for blood parameters, proximal composition, water-holding capacity, pH, lipid oxidation, and a* value of fillets. The L* and b* values of fillets showed differences (P < 0.05). Replacement between 21.95 and 38.75 % of SM protein by CGM protein (5.37 and 9.48 % of inclusion in the diet) improves the growth performance and body yield of pacu juveniles without altering blood parameters or affecting the fillet quality. 相似文献