Effect of fishmeal made from stale versus fresh herring and of added crystalline biogenic amines on growth and survival of blue shrimp Litopenaeus stylirostris fed practical diets

Six experimental diets were fed to satiety to juvenile Litopenaeus stylirostris (77-mg initial weight) in a 28-day feeding trial with 5 replicates per treatment and 15 shrimp per replicate. Diet 1 contained a fishmeal manufactured from fresh herring and diet 2 from stale herring of the same catch. Diets 3, 4, 5 and 6 contained the fresh herring meal but were supplemented with cadaverine (C) + histamine (H) + putrescine (P) + tyramine (T), CPT, HPT and CH, respectively, to obtain total biogenic amine concentrations similar to diet 2 but in different combinations. Survival, feed consumption and final biomass were significantly lower for the shrimp fed with the stale fishmeal. Individual weight and weight gain were significantly lower only with respect to diet 6 (supplemented with cadaverine and histamine). Feed conversion ratio was not affected by this fishmeal. The addition of amines to the fresh fishmeal had no effect on these parameters, except for diet 6, which displayed higher feed consumption, wet weight and final biomass. Polyamine concentrations of the hepatopancreas and remaining whole body were also measured at the end of the feeding trial. No significant differences were found for the different concentrations in the tissues, though cadaverine tended to be higher in the hepatopancreas of shrimp fed with the stale fishmeal and fed with the diets containing elevated levels of cadaverine, while spermidine tended to be higher in the hepatopancreas of shrimp, fed with diets containing combinations of H, P and T. The results suggest that fishmeal made from stale fish contains a factor or factors which are toxic to L. stylirostris, but that these factors are not biogenic amines, which appear not to have adverse effects on shrimp at the levels found in moderately stale fishmeal. However, the content of biogenic amines remains a good indicator of raw material spoilage, serving as a good quality criterion for fishmeal.