Effects of replacement of dietary fish oil with plant oil on growth performance and fatty acid composition of spinefoot rabbitfish, Siganus rivulatus

Abstract

A 95-day feeding study was carried out to evaluate the impact of complete replacement of fish oil by plant oils in the growth performance, feed consumption fatty acid and body composition of juvenile rabbitfish, Siganus rivulatus. There were four treatments i.e., A (fish oil diet), (linseed oil diet), C (soybean meal oil diet) and D (sunflower oil diet). The experimental trial was conducted in twelve 1.5-m³ fiber glass tanks (n=3). Spinefoot rabbitfish juveniles had an average initial weight of 0.948 g ± 0.124 g and they were stocked at 50 fish per tank. Fish fed diet A showed significantly better growth rate, final body weight, and total body weight than fish fed on the other diets. Moreover, the best FCR was observed for diet A followed by diet C and diets B and D had the worst FCR. Fish body composition for crude protein, dry matter, ashes and gross energy at the end of the trial had not differed between the treatments. The highest polyunsaturated fatty acids (PUFA) was found in fish fed diet A followed in decreasing order by diets D, B, and C. Fish oil is a better dietary lipid source for Spinefoot rabbitfish juveniles, Siganus rivulatus, than plant oils. Among plant oils, soybean oil was better than linseed oil and sunflower oil as the main dietary fat source.

Alternate abstract:

Um estudo de alimentaçâo de 95 dias foi realizado para avaliar o impacto da substituiçâo completa de óleo de peixe por óleos vegetais no desempenho de crescimento, composiçâo corporal e consumo de raçâo de juvenis de coelho, Siganus rivulatus. Houve quatro tratamentos, ou seja, A (dieta de óleo de peixe), (dieta de óleo de linhaça), C (dieta de óleo de farelo de soja) e D (dieta de óleo de girassol). O ensaio experimental foi conduzido em doze tanques de fibra de vidro de 1,5 m³ (n=3). Os juvenis de peixe-coelho-de-espinho apresentaram peso inicial médio de 0,948 g ± 0,124 g e foram estocados com 50 peixes por tanque. Os peixes alimentados com a dieta A apresentaram taxa de crescimento, peso corporal final e peso corporal total significativamente melhores do que os peixes alimentados com as outras dietas. Além disso, a melhor CAA foi observada para a dieta A seguida da dieta C e as dietas B e D tiveram a pior CA. A composiçâo corporal dos peixes para proteína bruta, matéria seca, cinzas e energia bruta ao final do experimento nâo diferiu entre os tratamentos. O maior teor de ácidos graxos poliinsaturados (PUFA) foi encontrado nos peixes alimentados com a dieta A seguido em ordem decrescente pelas dietas D, B e C. O óleo de peixe é uma melhor fonte de lipídios dietéticos para juvenis de peixe-coelho, Siganus rivulatus, do que os óleos vegetais. Entre os óleos vegetais, o óleo de soja foi melhor que o óleo de linhaça e o óleo de girassol como principal fonte de gordura da dieta.