Replacement of Artemia franciscana Nauplii by Moina minuta Neonates as Live Food on the Larviculture of Angelfish (Pterophyllum scalare -Schultze, 1823) and Severum (Heros severus - Heckel, 1840)

Abstract

The present study aimed to assess the potential substitution of Artemia franciscana nauplii with Moina minuta neonates as the initial feed for angelfish (Pterophyllum scalare) and severum (Heros severus), evaluating the fish growth performance, live food cost, and intestinal histomorphometry. To achieve this goal, two separate experiments were carried out for each species during 20 days, using 200 postlarvae. Both experimental designs consisted of five treatments, namely, 100% A. franciscana nauplii (A100-M0); 75% A. franciscana nauplii and 25% M. minuta neonates (A75-M25); 50% A. franciscana nauplii and 50% M. minuta neonates (A50-M50); 25% A. franciscana nauplii and 75% M. minuta neonates (A25-M75); and 100% M. minuta neonates (A0-M100), with four replications (10 postlarvae per repetition). Angelfish postlarvae fed with A100-M0, A75-M25, A50-M50, and A25-M75 had better values of final length (13.31 mm, 14.15 mm, 13.32 mm, and 13.32 mm), gain in length (7.91 mm, 8.75 mm, 7.92 mm, and 7.92 mm), and length-specific growth rate (4.51% day−1, 4.82% day−1, 4.51% day−1, and 4.51% day−1). In the case of severum postlarvae, the highest length growth performance occurred in those fed with A100-M0 (15.86 mm, 8.90 mm, and 4.12% day−1), A75-M25 (15.45 mm, 8.49 mm, and 3.99% day−1), and A50-M50 (14.78 mm, 7.82 mm, and 3.76% day−1). Both species (angelfish and severum postlarvae) fed with A100-M0 and A75-M25 presented higher values of final weight (28.88 mg and 34.49 mg; 55.84 mg and 53.95 mg), gain in weight (27.56 mg and 33.08 mg; 51.03 mg and 49.14 mg), and weight-specific growth rate (15.42% day−1 and 16.30% day−1; 12.26% day−1 and 12.09% day−1). Live food cost for angelfish and severum postlarvae was higher in A100-M0 (US$ 0.92 and US$ 1.08) and lower for the ones in A0-M100 (US$ 0.36 and US$ 0.35). Severum postlarvae fed with A100-M0 (57.20 µm), A75-M25 (55.66 µm), and A50-M50 (54.27 µm) presented the highest intestinal villi heights. Thus, partial replacement of A. franciscana nauplii by M. minuta neonates in the proportion of A75-M25 or 100A-0M is viable and effective during the first feed of these fish species.