Dietary amino acid profiles and growth performance in juvenile kuruma prawn Marsupenaeus japonicus

Investigation of the characteristics of different shrimps by species and habitat using gas chromatography/mass spectrometry based metabolomics

Approximately 6.5 million tons of shrimp are consumed annually worldwide. The price of shrimp is greatly influenced by species and habitat (e.g., farmed vs wild-caught). In recent years, false labeling has become a problem in the shrimp industry. False labeling can include species, habitat (whether farmed or wild-caught). This problem is motivated by the potential for economic benefit, and significantly reduces the consumer reliability of food. As a first step in establishing a detection method, we took a metabolomics approach to elucidate phenotypic diversity by assessing genetic differences and environmental factors. Metabolites identified by gas chromatography/mass spectrometry (GC/MS) analysis were subjected to multivariate analysis to identify metabolites that correlated with shrimp species and habitat. The characteristics based on species and habitat were observed respectively. For species, the classification approximately tended to be based on taxonomy. It suggests that species different have strong effect on metabolite profiles. In particular, the difference between Panaediae and Pandalidae was significantly observed, and some fatty acids such as palmitoleic acid and elaidic acid are abundant in Pandalidae. Among Pandalidae, Japanese tiger shrimp was characterized by metabolites related to purine metabolism. For habitat, farmed shrimp had a high amino acid content, and wild caught shrimp had a high fatty acid content. Habitat-based separation was observed in Indonesian black tiger shrimp samples, indicating that metabolites such as glycolic acid, phosphate, and pentadecanoic acid are characteristic components of natural black tiger shrimp.

Ontogenetic changes in energetic reserves, digestive enzymes, amino acid and energy content of Lithodes santolla (Anomura: Lithodidae): Baseline for culture

The southern king crab (SKC) Lithodes santolla is an important commercial species in southern South America. Fishing pressure has caused the deterioration of its stocks. Currently, culture techniques are being developed for producing SKC juveniles to enhance the natural population and to recover the fishing stock. Therefore, it is necessary to know about physiology, energetic and nutritional requirements for SKC maintenance in hatchery. Thus, this study aims to evaluate the biochemical and physiological changes in the midgut gland, muscle and hemolymph of juveniles, pre-adults and adults of wild SKC. The energetic reserves, digestive enzymes activity, amino acid profile and energy were quantified in twelve juveniles, ten pre-adult, and ten adult crabs. Juveniles showed high glycogen and low lipids in the midgut gland, and low proteins and low lactate in muscle. In the hemolymph, juveniles had high lipids. Pre-adults had high glycogen and lipids in the midgut gland, and both high protein and lactate in muscle. In the hemolymph, pre-adults had high lipids. Adults had low glycogen and high lipids in midgut gland, and both high proteins and high lactate in muscle. In hemolymph, adults had high glucose and lactate. Juveniles and pre-adults had high proteinase activity, whereas adults had high lipase activity. Major essential amino acids of SKC were arginine, methionine, and tryptophan, and the non-essential amino acids were glycine, aspartic acid and glutamic acid. On another hand, SKC had similar energy in the midgut gland and muscle, regardless of the ontogenetic stage. Moreover, we demonstrated that the biochemical energy calculation underestimates the actual measured values by a calorimeter. Thus, our results help to understand the physiological changes, energetic and nutritional requirements of L. santolla, and this study is a baseline for research on diet formulation for maintaining this species under culture conditions.

Maintenance and growth requirements for nitrogen, lysine and methionine and their utilisation efficiencies in juvenile black tiger shrimp, Penaeus monodon, using a factorial approach

We used a factorial approach to distinguish maintenance from growth requirements for protein, lysine and methionine in the black tiger shrimp, Penaeus monodon. Juvenile P. monodon (initial weight 2.4 g) were fed during 6 weeks one of ten semi-purified diets based on casein and purified amino acids (AA) as N source. The diets contained four levels of crude protein (CP, from 5 to 54 % DM diet) with two levels (% CP) of lysine or methionine (normal or 30 % deficient). Requirements were determined using linear and non-linear regression models. We could thus obtain the first ever data on maintenance (N equilibrium) requirements for CP and AA in P. monodon. CP requirements for maintenance (4.5 g/kg body weight (BW) per d) represented approximately 19 % of the CP requirement for maximal N gain (23.9 g/kg BW per d). The marginal efficiency of utilisation reached a maximum of 38 % for N, 0.77 for lysine and 1.62 for methionine using N gain as response. Lysine requirements were 0.20 g/kg BW per d for N maintenance and 1.40 g/kg BW per d for maximal N gain. Methionine requirements were 0.11 g/kg BW per d for N maintenance and 0.70 g/kg BW per d for maximal N gain. The lysine (5.8 %) and methionine (2.9 %) requirements for maximal N gain, expressed as percentage of protein requirement, agree with literature data using a dose-response technique with smaller P. monodon. The observed interaction between dietary CP and methionine for N gain demonstrates that requirements for indispensable AA (expressed as % CP) cannot be evaluated separately from CP requirements.

Supplemental effects and metabolic fate of crystalline arginine in juvenile shrimp Marsupenaeus japonicus

Feeding experiments with juvenile kuruma shrimp (Marsupenaeus japonicus) were conducted to understand the effects of supplemental levels of crystalline arginine hydrochloride on the growth and assimilation of arginine. In experiment 1 the juvenile shrimp were maintained on diets with and without arginine supplements. The addition of 3.0% arginine to a casein-based diet was slightly effective in improving the growth of the juveniles. In experiment 2, tracer experiments using [14C] arginine were conducted to clarify the ingestion and assimilation of arginine, 9 and 24 h after feeding, at different levels of supplemental arginine. Tracer experiments showed that the leaching rate of arginine 1 h after feeding ranged from 16 to 26% in the diets with different levels (0, 0.1, 1.5, 3.0 and 6.0%) of supplemental arginine; that is, 74-84% of the given arginine was actually ingested by the shrimp fed the diets. However, with increasing levels of supplemental arginine the incorporation rate of arginine into the whole body decreased and the utilization of absorbed arginine for body protein synthesis was reduced, whereas the excretion of absorbed arginine was increased. Thus, the absorbed arginine was not effectively utilized for body protein synthesis when large amounts of arginine were supplemented to the diets.