Effects of reduced protein level and dietary amino acid supplementation on growth, body composition and intestinal morphometry of silver catfish ( Rhamdia quelen )

Abstract

The reduction in the protein level and the supplementation of lysine (Lys) and methionine (Met) in the diet were evaluated in the performance and intestinal morphometry of silver catfish (Rhamdia quelen). The study was used in a completely randomized design for 63 days, where 320 fish (26.33 ± 0.40 g) were distributed in 20 tanks (250 L, 16 fish each) and fed until the apparent satiety was reached. Five diets were formulated, a positive control [38% of crude protein (CP) (38CP)], a negative control [34% of CP (34CP)] and three test diets [34% of CP supplemented with Lys (34L), 34% of CP supplemented with Met (34M) and 34% of CP supplemented with Lys plus Met (34LM)]. Final weight and condition factor were greater in fish fed the 34LM diet than in those fed the 34CP diet (p < .05). Body lipid deposition was lower in fish fed the 34CP diet than other diets (p = .0002). In the fillet, there was a lower deposition of lipids in fish fed with 34L diet than in fish fed with 34M and 34LM diets (p <.0001). Fish fed the 34LM diet had a higher AA content in the plasma than those fed 34L and 34CP diets (p < .0001). The lower villus height was observed in fish fed the 34L diet compared to the 38CP diet (p = .021). It is possible to reduce 4% of the CP level in silver catfish diets with supplementation of Lys and Met.

Metabolical and hematological responses of silver catfish (Rhamdia quelen) to diet composition

“…Diets with insufficient amounts of protein or inadequate amino acid composition cause reduced growth and decreased feed efficiency due to mobilization of proteins in some tissues in order to maintain vital functions (HU et al, 2021;LIM et al, 2011;SCHNEIDER et al, 2020). In this study, a combination of different protein sources was performed in order to seek an adequate amino acid profile for the growth phase of the silver catfish, also seeking to analyze the metabolic and hematological behavior of the fish after consumption of the diets.…”

“…However, diets combined with protein sources of animal origin and soybean meal showed a better amino acid profile estimated for the species (MEYER; FRACALOSSI, 2004). It should be noted that amino acid supplementation is a promising method to increase the nutritional value of diets in which fish meal is replaced by vegetable protein sources (JIANG et al, 2019;LIM et al, 2011;SCHNEIDER et al, 2020).…”

Exigências nutricionais para bagres nativos do Brasil: uma revisão

“…Deste modo, na fase inicial exigem aproximadamente 40% de PB (Hernández et al, 2018;Signor et al, 2004) e após atingirem em média 25 g, a exigência proteica é reduzida para 35% de PB (Reidel et al, 2010). Entretanto, recomenda-se a suplementação com lisina e metionina para um maior desempenho, melhora na composição corporal e morfometria intestinal (Schneider et al, 2020). Posteriormente, ao atingirem em média 130g, pode haver uma redução nos valores proteicos para 32 % (Adorian et al, 2017) e já na fase final de crescimento (>350g), dietas com 28 % de PB são aceitas (Coldebella et al, 2011).…”