Soybean lecithin dietary supplementation inOctopus vulgarisformulated feeds: Growth, feed efficiency, digestibility and nutritional composition

Abstract

Soybean lecithin dietary supplementation was tested on Octopus vulgaris performance in individual or grouped kept animals. Individually reared animals were fed two semi‐moist diets (N = 8) without (VEGENAT‐LS0) or with supplementation (VEGENAT‐LS2, substituting 20 g/kg of starch by lecithin). VEGENAT‐LS2 had higher polar and total lipid content (p < 0.05). Growth (1.1%–1.3%BW/day), feed intake (2.2%BW/day) and feed efficiency (48%–60%) were similar (p > 0.05). VEGENAT‐LS0 presented higher dry matter, protein and lipid digestibility (p < 0.05). VEGENAT‐LS2 increased lipids in carcass and whole animals (p < 0.05) but preserved lipid classes proportion. Group kept octopuses (N = 10) were fed a mixed natural diet (2BOGUE:1CRAB) or VEGENAT‐LS2. VEGENAT‐LS2 had lower protein but higher polar lipid content (p < 0.05). VEGENAT‐LS2 presented less growth (1.1% vs. 1.8%BW/day), feed intake (1.8% vs. 3.2%BW/day) and similar feed efficiency (53.5% vs. 59.9%). Dry matter and protein digestibility were similar while lipid digestibility was significantly lower in 2BOGUE:1CRAB (31.8% vs. 65.4%). VEGENAT‐LS2 digestive gland presented higher mineral and carbohydrate contents and lower triglycerides (p < 0.05), while a similar macronutrient composition was analysed in the carcass and whole animals. Individual or group keeping did not affect VEGENAT‐LS2 performance. In conclusion, dietary soybean lecithin supplementation did not promote a performance enhancement.

Performance of Marine Lecithin Supplemented Feeds for the Common Octopus (Octopus vulgaris) Ongrowing: Changes in Proximate Composition and Lipid Classes’ Profile

“…In contrast, Morillo-Velarde et al [10] did not report any effect on FE (in individual reared octopus during the same experimental period) when supplying lipid supplemented feeds with fish oil. In the present study, a decrease of FE was only observed during the second ongrowing month, i.e., in the long term, similar to what was reported when feeding a supplemented soybean lecithin diet [54]. However, in both cases (the present and the latter), this FE reduction was not so acute when compared to those reported to occur when octopus were fed with fish oil supplemented feeds [10].…”

“…Considering the whole experimental period (days 0-56), the best growth and feed efficiency were obtained in animals fed the diet without marine phospholipids supplementation (CALPRO). Bearing in mind the present and the similar results reported by Rodríguez-González et al [54], it seems that the inclusion of 20g/kg of phospholipids in formulated feeds, from animal marine (marine lecithin) or vegetable (soybean lecithin) sources, do not have a beneficial effect on octopus growth (AGR and SGR), ingestion (AFR and SFR), feed efficiency (FE) or food conversion (FCR). Other studies also showed a negative effect or no benefit related to the inclusion of lipids in formulated feeds [7,10,54] or when octopus were fed natural diets with a high fat content [20,56,57].…”

“…In contrast, during the second month, SGR was similar between both diets (SGR of 0.88 ± 0.16 and 0.81 ± 0.25%BW/day for CALPRO and CALPRO-LM, respectively; p > 0.05) but values were lower than in the first month. This decrease in SGR after a given time was previously reported by other authors who were testing prepared diets in the species [6,7,13,54,55]. If this issue is exclusively related to the formulation itself or if it has some relation to the species behavior remains to be determined, as the feeding rates were maintained.…”

“…Another remarkable issue was the higher disintegration rates in water (WSI) observed in the CALPRO-LM feed, pointing to a negative effect of lecithin supplementation on the stability of CALPRO formulation. A decrease in stability after being submerged for 24 h in seawater was also observed when soybean lecithin was included in a semi-moist feed tested previously in common octopus [54]. In contrast, the inclusion of fish oil in the same type of feed provided a higher stability [10].…”

“…The only registered mortality was observed in a CALPRO-LM experimental tank at day 46 and had no relation whatsoever to the feeding conditions. A previous experiment performed with fish oil-supplemented diets also showed 100% survival [10], while the inclusion of soybean lecithin generated a 12.5% mortality rate [54].…”