Evaluation of the potential of Andean lupin meal (Lupinus mutabilis Sweet) as an alternative to fish meal in juvenile Litopenaeus vannamei diets

Abstract

Two growth trials were conducted with juvenile Litopenaeus vannamei using experimental diets providing 35% protein and 11% lipid, where 0, 25, 50, 75 and 100% of fish meal protein (FM) was substituted by lupin kernel meal (LKM). Before grinding the lupin seeds, the alkaloids, hull and fat were removed by specific methods. In an indoor clear water aquarium trial, juvenile shrimp (initial weight 1.23 ± 0.22 g) were stocked at 8 per 50 L aquarium, with 6 replicate aquaria assigned to each treatment in a completely random design. At the end of the 57-day feeding trial, the average survival of the shrimp was N80% and there was no variation (P N 0.05) when FM was replaced partially nor totally with LKM. The results of this study showed that LKM can replace 50% of FM protein without significantly discouraging growth (6.7 7.0 g final weight) (P N 0.05), but the substitution of 75 and 100% resulted in lower growth (4.8 5.2 g final weight). The inclusion of LKM at any of the tested levels resulted in a statistical reduction (P b 0.05) of the apparent dry matter digestibility (ADMD) and apparent protein digestibility (APD) of the feed. The gradual increases of LKM in diets produced a significant decrease (P b 0.05) in ingestion rate. To demonstrate the inherent effects of water quality and natural food sources found in shrimp ponds, a growth trial was conducted in 1-m2 bottomless cages in a single 1000-m2 pond greenhouse. Juveniles weighing 5.84 ± 0.25 g (mean ± SD) were stocked in the cages at a density of 30 individuals per m2. The feed was offered on a tray twice a day for 45 days. Five replicates were performed for each treatment. At the end of the 45-day field evaluation, no significant differences (P N 0.05) in final weight (11.1 12.2 g), specific growth rate (1.4 1.6 % day−1), survival (69 79%) nor FCR (2.0 2.3) were found in any of the experimental shrimp diets. These findings show that Lupinus mutabilis Sweet has very good potential as an alternative protein source replacing at least 50% of protein from FM, equivalent to one third of the total protein in the diet for growth-out phase of L. vannamei. The study should be repeated under pond conditions to corroborate results obtained in cages and assess the cost benefit of including this ingredient in commercial feeds