Nutritive value of partially dehulled and extruded sunflower meal for post-smolt Atlantic salmon (Salmo salar L.) in sea water

Abstract

This study determined the digestibility of protein in partially dehulled sunflower meal (SFM) and then, as the main goal, the nutritive value of high‐temperature extruded (≤149°C) partially dehulled SFM (SFMEX) for post‐smolt Atlantic salmon Salmo salar in sea water. The digestibility study was conducted using the settling column approach (‘Guelph system’) for faeces collection as described by Hajen, Higgs, Beames and Dosanjh. In the nutritive value study, triplicate groups of 50 salmon (mean weight ∼116 g) in 4000‐L outdoor fibreglass tanks supplied with 25–40 L min−1, filtered, oxygenated (dissolved oxygen, 7.0–8.5 mg L−1), 11–12°C sea water (salinity, 29–31 g L−1), were fed twice daily to satiation one of five steam‐pelleted dry diets that contained 422 g of digestible protein (DP) kg−1 and ∼16.4 MJ of digestible energy (DE) kg−1 on a dry weight basis for 84 days. Low‐temperature‐dried anchovy meal (LT‐AM) comprised 68.2% of the basal diet protein whereas in four test diets, SFMEX progressively replaced up to 33.0% of the DP provided by LT‐AM in the basal diet (SFMEX≤271 g kg−1 of dry matter). Sunflower meal had 87.9% DP. Diet treatment did not significantly affect specific growth rate (1.39–1.45% day−1), feed efficiency (1.19–1.26), percentage of dietary protein retained (45.8–47.5), gross energy utilization (46.5–49.4%), per cent survival (96.0–99.3) or terminal whole body and muscle proximate compositions. We conclude that SFMEX can comprise ≥271 g kg−1 of the dry diet or ≥22.7% of the digestible dietary protein of post‐smolt Atlantic salmon in seawater without any adverse effects on their performance.

A study of partial replacement of fish meal with sunflower meal on growth, amino acid retention, and body composition of sharpsnout seabream, <I>Diplodus puntazzo</I> (Actinopterygii: Perciformes: Sparidae)

“…Regarding feed efficiency parameters, Sánchez Lozano et al (2007) showed an increment in FI whereas Olvera Novoa et al (2002) reported a reduction in FI as the SFM substitution increased. Gill et al (2006) reported similar results to our study with regard to PER.…”

“…In body composition, only fish fed diet with11.7% SFM inclusion obtained the lowest value in CP indicating that the vegetal meal did not affect body composition, which was similar to the results of Gill et al (2006) and Sánchez Lozano et al (2007) results. However, OlveraNovoa et al (2002) obtained statistical differences not only in CP but also in CL, ash and humidity as a consequence of SFM inclusion leading to a reduction of CP and an increase in CL and ash content.…”

“…It was possible that the omnivorous habits of the sharpsnout seabream enabled this species to accept a diet with up to 7% CF content without affecting their final growth. Similar results were presented by Gill et al (2006) who substituted fish meal with 33% dehulled SFM in Salmo salar although these authors only reported 3.65% CF in the maximal inclusion. Mena Sellés and García García (2002) reported that one of the preferred foods of D. puntazzo, especially in autumn and winter, was algae.…”

“…Furuya et al (2000) suggested that better fish growth and efficiency was related to a well balanced amino acid profile. In addition, Gill et al (2006) did not report statistical differences in FI, but they did report an increase in FI as the SFM inclusion increased.…”

“…The following maximal substitutions of SFM were obtained without statistical differences: 12% in gilthead seabream (Sánchez Lozano et al 2007); 22% in rainbow trout (Martínez 1984, Sanz et al 1994; 60% in tilapia (Furuya et al 2000, Maina et al 2003; and 20% in Tilapia randalli fingerlings. Similarly, in Atlantic salmon, SFM substitution up to 33% was reported without any adverse effects on final fish weight (Gill et al 2006). The metabolisable energy of SFM is low (8371 kJ · kg -1 ) when compared to other oil meals (Ahmad et al 2004).…”