Soybean and linseed oils as an alternative to fish oil in diets of the juvenile tambaqui, Colossoma macropomum

• Ano de defesa: 2019
• Autor(a) principal: Modesto, André Luiz Souza
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Tambaqui (Peixe) - Nutrição; Óleos de peixe; Lipídios na nutrição animal; Musculos - Crescimento; Tambaqui (Peixe) - Registros de desempenho; Óleos vegetais; Piscicultura
• Link de acesso: https://locus.ufv.br//handle/123456789/28404

In aquicola production, the use of fish oil as the main lipid ingredient of diets as a function of the energy supply and mainly of essential fatty acids is common. However, with the decrease in fish stocks, fish oil has become a scarce and consequently high value ingredient. Thus, it is necessary to search for new ingredients that can partially or totally replace fish oil in diets for aquatic organisms. In this aspect, the vegetable oils have been highlighting due to the high production and availability associated with the lowest cost. However, for replace fish oil with vegetable oils, research should evaluate the effect of such ingredients on the development and metabolism of various fish species. Therefore, with this research, the objective was to evaluate source and levels of oils in diets for tambaqui, Colossoma macropomum. We conducted a study to evaluate productive performance, muscle growth and energy metabolism. We used a randomized block design, with four treatments and four replicas arranged in a 2x2 factorial design. The sources were 100% fish oil and mixture containing 60% soybean oil and 40% linseed oil and inclusion levels of 5% and 10% oils. We selected fish in the following weight classes: B1: 6.9 ± 0.5 g; B2: 8.6 ± 0.5 g and B3: 10.3 ± 0.5 g. The fish were fed for 9 weeks. We evaluated the survival rate, weight gain, daily growth rate, body condition factor, carcass yield, feed conversion, viscerosomatic fat index, hepatosomatic and viscerosomatic index, glucose levels, total cholesterol, high (HDL) and low (LDL) density lipoproteins and triglycerides plasma, hepatic and muscular glycogen and muscle growth of fish. We observed that sources and levels of oil did not affect weight gain, daily growth rate, carcass yield and feed conversion. We noted that fish fed with 5% of fish oil had the lowest value for the condition factor. Fish fed with 10% oil, regardless of source, had the highest values for viscerosomatic index and viscerosomatic fat. However, the lowest values of the hepatosomatic index were observed in fish fed with 10% of oil. For HDL, triglycerides and hepatic glycogen were observed the highest values in the fish that received the diet containing the mixture of soybean and linseed oil, regardless of the level. The lowest values of LDL were found in these same fish. The lower frequency of muscle fibers of less than 20 μm was observed in fish fed with the diet containing 5% of soybean oil and linseed oil. For muscle fibers with diameter greater than 20 μm and less than 50 μm the highest frequency was observed in the fish that received the mixture of oils, regardless of the level used. We repaired a higher value of moisture in the carcass of the fish fed with 5% of the mixture of soybean oils and linseed. Lipid and carcass energy were higher for fish that consumed 10% oil inclusion independent of the source and ash had lower values for the same level. We conclude that is possible to substitute the fish oil with the mixture containing 60% soybean oil and 40% linseed oil and inclusion level of 5%.