Exigência protéica de juvenis de tainha Mugil platanus
Feed is one of the main costs for fish culture. Studies looking for higher feed efficiency are important to increase the success of aquaculture and reduce impacts of nutrient emission into the environment. Considering the potential of the mullet Mugil platanus for aquaculture, as well as the lack of information on its nutritional demands, the main goal of the present work was to determine the dietary protein requirement of juvenile mullets. Five isocaloric diets were formulated in order to contain increasing levels (30, 35, 40, 45, and 50%) of crude protein (CP) corresponding to 18.7 MJ metabolizable energy/Kg. All diets were tested in triplicate. Each experimental unit was composed of a 50 L tank with 50 juveniles (mean ± SE initial weight and length equal to 1.17 ± 0.02 g and 4.34 ± 0.03 cm, respectively). Diets were offered five times a day until apparent satiation for 35 days. No significant difference (P > 0.05) was observed in survival rate, feed efficiency and body composition between treatments. However, weight increase, feed ingestion and specific growth rate was higher in fish fed the 35% CP level than those fed the highest protein content diet (50% CP). The amount of postprandial ammonia excreted by mullet was linearly related to protein intake. Intestinal tryptic activity was inversely proportional to the percentage of dietary CP. The dietary protein requirement of juvenile mullet was estimated as 34.28% CP with a P:E ratio of 18.7 g/MJ.
Advisor:Luís André Nassr de Sampaio; Marcelo Borges Tesser; Maude Regina de Borba; Dalton José Carneiro
School:Fundação Universidade Federal do Rio Grande
Source Type:Master's Thesis
Date of Publication:07/29/2008