Feeding rate and frequency during the first feeding of angelfish (Pterophyllum scalare - Schultze, 1823) and severum (Heros severus - Heckel, 1840) with Moina sp

The aim of the present study was to determine the best feeding for angelfish (Pterophyllum scalare) and severum (Heros severus) post-larvae fed with Moina sp. during their first feeding phase. For this purpose, growth performance and intestinal histomorphometry of angelfish and severum post-larvae under different feeding rates and frequencies were evaluated. The experiment was conducted for 20 days. 320 angelfish and severum post-larvae with five days post-hatch were used. Angelfish post-larvae had an average initial length and weight of 6.17 ± 1.11 mm and 2.35 ± 1.17 mg, whereas severum post-larvae had an average initial length and weight of 6.61 ± 0.34 mm and 3.12 ± 0.37 mg, respectively. The experimental design was completely randomized, in a factorial scheme (4 × 2), with four different feeding rates: 100, 200, 300 and 400 Moina sp. post-larvae−1 day−1, divided into two and four times per day, with four replicates for each treatment. No interaction (p > 0,05) was observed between feeding rate and frequency. The highest values of final length, length gain and specific growth rate for length were observed in angelfish post-larvae fed 300 and 400 Moina sp. post-larvae−1 day−1, while these variables were higher only for severum post-larvae fed 400 Moina sp. post-larvae−1 day−1. The highest values of final weight, weight gain, specific growth rate for weight and allometric condition factor were observed in both species fed 400 Moina sp. post-larvae−1 day−1. Height, width and area of intestinal villi were higher in angelfish post-larvae consumed 300 and 400 Moina sp. post-larvae−1 day−1. The same result was found for width of intestinal villi of severum post-larvae. Height and area of the intestinal villi were higher only in severum post-larvae fed 400 Moina sp. post-larvae−1 day−1. There was no effect of the feeding frequency on any of the evaluated parameters. Overall, based on the obtained results, it is recommended for both species a feeding rate of 400 Moina sp. post-larvae−1 day−1 divided in two times a day. •Angelfish and severum post-larvae should be fed Moina sp. twice a day.•Feeding rate of 400 Moina sp. post-larvae−1 day−1 is the most suitable.•Growth performance of angelfish and severum is influenced only by the feeding rate.•Intestinal epithelial tissue of angelfish and severum is influenced by the feeding rate.