Protein requirement in the diet of Heros severus (Heckel, 1840): An Amazonian ornamental fish

Abstract

Two experiments to determine the crude protein (CP) requirement of Heros severus were performed. Five isocaloric (3,200 kcal kg−1 of digestible energy) diets containing five levels of CP (28, 32, 36, 40, and 44%) were evaluated. In the first, 75 fingerlings were distributed among 15 aquaria (30 L). In the second experiment, 100 juveniles were distributed among 20 aquaria (50 L). A quadratic effect on weight gain, specific growth rate for weight and for length, feed intake, feed conversion, body proteins, body lipids, and ash content of fingerlings occurred with increasing dietary CP, with optimum values estimated at 41.86, 40.30, 40.97, 39.60, 43.55, 40.64, 37.77, and 37.50% of CP, respectively. A linear effect on protein efficiency ratio of fingerlings occurred with increasing dietary CP. A quadratic effect on weight gain, specific growth rate for weight, feed conversion, hepatosomatic index, and body lipids of the juveniles were observed with increasing dietary CP, with optimum values estimated at 37.03, 37.20, 38.40, 35.13, 38.78, and 34,74% of CP, respectively. A linear effect on feed intake, protein efficiency ratio, and viscerosomatic index of juveniles occurred with increasing dietary CP. Blood glucose and hematocrit had lower values in juveniles fed a low level of CP.

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“…Therefore, the use of Biofloc technology in aquaculture is highly profitable since, as mentioned above, it improves water quality and increase the survival of organisms, as mentioned by Avilés et al [30] . On the other hand, a close relationship is established between fish growth and diet digestibility, especially the protein fraction as the primary factor in their diet, since it is one of the most important nutrients for this process [31,32] . However, some studies report a positive effect of pigments on fish growth, like Pérez-Escalante [33] study which obtain a positive effect in the diet with Jamaican pigments (Hibiscus sabdariffa) on growth, weight gain and survival in Carassius auratus (Goldfish).…”

Porphyridium cruentum (red microalga) added in Biofloc system to growth and pigmentation source of Heros severus.

“…Therefore, the use of Biofloc technology in aquaculture is highly profitable since, as mentioned above, it improves water quality and increase the survival of organisms, as mentioned by Avilés et al [30] . On the other hand, a close relationship is established between fish growth and diet digestibility, especially the protein fraction as the primary factor in their diet, since it is one of the most important nutrients for this process [31,32] . However, some studies report a positive effect of pigments on fish growth, like Pérez-Escalante [33] study which obtain a positive effect in the diet with Jamaican pigments (Hibiscus sabdariffa) on growth, weight gain and survival in Carassius auratus (Goldfish).…”

Evaluation of growth development and pigmentation of Heros severus cultured in a biofloc system with enriched pigment diets

“…Therefore, they could compete for food, even though it was always given considering the 10% of the organisms' total weight in the culture medium. This condition causes stress in the organisms; therefore, their growth is slower due to food competition (De Sousa et al 2020). DeLara et al (2017) studied Puntius conchonius fed a trout-based diet in a biofloc system with 60% protein produced by incorporating molasses and rice flour.…”