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Nonconventional feed ingredients for different aquatic species need to be tested to establish their nutritional value. Thus, this study assessed the use of canary seed (CS), Phalaris canariensis L., and giant kelp seaweed (KS), Macrocystis pyrifera, as ingredients for Nile tilapia, Oreochromis niloticus L., feed. Two feeding trials were conducted: (1) Growth trial, where seven feeds were tested; a control diet (CD) and six CS/KS diets (100, 200, 300 g/kg). Fish fed CS/KS diets (100 and 200 g/kg) had similar weight gain to those fed CD, whereas CS/KS diets (300 g/kg) decreased growth performance (p < 0.05). The CS‐diet Economic Conversion Ratios and KS100 diet were similar to CD, while KS inclusion levels (200, 300 g/kg) decreased this parameter (p < 0.05). Dietary KS inclusion of 300 g/kg significantly decreased the profit index compared with CD and CS‐diets (p < 0.05, 2), digestibility trial, where nine feeds were evaluated: a reference diet (RD); six CS/KS diets (100, 200, 300 g/kg) to determine diet digestibility, and two CS/KS diets (300 g/kg) to determine ingredient digestibility. CS dry matter, protein, and lipid digestibility were higher than KS (p < 0.05). The results suggest that CS has higher nutritional value than KS for Nile tilapia. [ABSTRACT FROM AUTHOR]

The nutritional value of three safflower, Carthamus tinctorius, meals used as ingredients in diets for Litopenaeus vannamei was determined in terms of chemical composition and in vivo and in vitro digestibility. Three safflower meals were used: a whole safflower meal (WSM; 20.6% crude protein and 34.6% lipids) prepared in our laboratory; a low-protein safflower meal (LPSM; 27.5% crude protein and 1.8% lipids) and a high-protein safflower meal (HPSM; 36.7% crude protein and 1.0 lipids), both produced at commercial scale. The most abundant essential amino acid in safflower meals was arginine, while lysine and methionine were the least abundant; the most important fatty acids were oleic, linoleic, palmitic, and stearic acids. Apparent protein digestibility of HPSM (89.4%) and LPSM (87.6%) meals were significantly higher than that of WSM (72.3%). Lipid digestibility of WSM (93.7%) was higher than that of the defatted meals (LPSM 76.1% and HPSM 60.7%). Carbohydrate digestibility was very high (>96.8%) in all safflower meals. In vitro pH-stat protein digestibility and in vivo protein digestibility were significantly correlated. LPSM and HPSM have chemical compositions and digestibilities more suitable to be used as ingredients for shrimp feeds, especially HPSM, which could be used as source of digestible protein and carbohydrates. [ABSTRACT FROM AUTHOR]

Early weaning in spotted sand bass larvae, Paralabrax maculatofasciatus, was evaluated, testing a combination of two weaning times, 17 and 22 d after hatching (d.a.h.), and three different microparticulate diets. Protein in diets was mainly from sardine meal and from 15% squid meal, beef blood meal, or fish protein hydrolysate. Anatomical (standard length), histological (gut development), and biochemical (highly unsaturated fatty acids) parameters were measured in larvae, as well as survival and resistance to a stress test measured 40 d.a.h. For larvae weaned at 17 d.a.h., the best growth and survival were obtained with diets containing fish protein hydrolysates; for larvae weaned at 22 d.a.h., best results were obtained with squid meal and fish protein hydrolysate. Growth and survival were significantly lower when using beef blood meal in both weaning treatments. The best relative and total survival were for larvae weaned at 22 d.a.h. After the resistance test, 100% survival occurred in larvae fed on any microparticulate diet and either weaning treatment. No significant differences in arachidonic acid, eicosapentaenoic acid, or docosahexaenoic acid concentrations in fish fed on any diet occurred. Results suggest that weaning at 22 d.a.h. with diets containing fish protein hydrolysate or squid meal is preferred by this species. [ABSTRACT FROM AUTHOR]