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Principales rutas metabólicas. Utilización de la energía
... Los crustáceos al igual que la mayoría de los organismos vivos usan básicamente las mismas reacciones para producir la energía que necesitan para sostener los procesos vitales, los mismos tipos de compuestos y mecanismos para construir sus macromoléculas y los mismos conjuntos de reacciones para sintetizar los compuestos que intervienen en las diferentes reacciones bioquímicas (47). Las células de los crustáceos, y naturalmente de los camarones necesitan un gran número de compuestos preformados los cuales deben estar en la dieta ya sea porque los organismos no son capaces de sintetizarlos (esenciales) o porque son necesarios para cubrir las demandas de energía necesaria para mantenerlos con vida, crecer y reproducirse (47). ...
... Los crustáceos al igual que la mayoría de los organismos vivos usan básicamente las mismas reacciones para producir la energía que necesitan para sostener los procesos vitales, los mismos tipos de compuestos y mecanismos para construir sus macromoléculas y los mismos conjuntos de reacciones para sintetizar los compuestos que intervienen en las diferentes reacciones bioquímicas (47). Las células de los crustáceos, y naturalmente de los camarones necesitan un gran número de compuestos preformados los cuales deben estar en la dieta ya sea porque los organismos no son capaces de sintetizarlos (esenciales) o porque son necesarios para cubrir las demandas de energía necesaria para mantenerlos con vida, crecer y reproducirse (47). ...
... Shrimp species of the family Penaeidae are omnivores, although some do have carnivorous or herbivorous tendencies. They have broad biochemical capacities to use diverse energetic sources as elements in their diet (Rosas and Carrillo 2006). Pacific white shrimp L. vannamei prefers protein over carbohydrates as an energy source, meaning it has rather high dietary protein requirements (Tacon 1989; García-Galano 2006). ...
... However, it also use carbohydrates, mainly as a direct source of metabolic energy, as a substratum for chitin synthesis and for nucleic acids synthesis (Gaxiola et al. 2006 ). In addition to functioning as an energy source in L. vannamei, lipids are essential elements in cell structure and function, steroid hormone precursors, intercellular mediators, and are vital to nauplii growth, maturity and production (Rosas and Carrillo 2006). Using culture-independent methods such as DGGE (Avilés-Gómez 2011), our research group has studied bacterial flora composition in the digestive tract of shrimp at different stages, when fasting, when given feed with and without antibiotics, in juveniles, adults, males and females. ...
Bacteria capable of producing different extracellular enzymes of potential relevance in digestive processes were isolated from the stomach, hepatopancreas and intestine of Pacific white shrimp Litopenaeus vannamei. A total of 64 strains with proteolytic activity were isolated and grouped into 16 clusters based on morphological characteristics: 4 groups were isolated from the intestine; 5 from the hepatopancreas; and 7 from the stomach. Molecular methods (16S rRNA gene amplification and sequencing) and phenotypic criteria (Gram stain, catalase and oxidase tests, cell and colony morphology) were used to identify strains, which corresponded to Pseudoalteromonas and Vibrio genera. These genera are reported to form part of the digestive tract microbial community in shrimp. Both genera were isolated from all three tested tissues. One member of each morphologic group was selected for analysis of the presence of amylases, lipases/esterases and chitinases. Most of the strains had all the tested enzymes, indicating that the L. vannamei digestive tract microbiotic flora includes groups which have the potential to contribute to the degradation of dietary components.
... vitellogenin) involved in AG transfer into OV (Kanazawa and Teshima, 1971), and therefore its low levels of cholesterol in HP could be explained by a higher cholesterol turnover related to vitellogenin synthesis and transport to OV. Hemocyanin plays a key role in oxygen transport and protein reserves in hemolymph (Chen and Cheng, 1993) and also participates in shrimp immune response (Pascual et al., 2003 ). Its levels are affected by the molting process (Bursey and Lane, 1971, Cheng et al., 2002) and dietary protein levels (Rosas and Carrillo, 2006). In the present study, hemocyanin levels of wild females were lower than domesticated ones. ...
A 30-day trial was performed to evaluate the reproductive performance of wild and 2nd generation domesticated Farfantepenaeus duorarum broodstock. Changes in biochemical composition and fatty acids (FA) profile in the 1st and 4th spawn order females were used as indicators of nutritional condition. Wild population of F. duorarum presented significantly better reproductive outcomes as compared to domesticated ones. Wild spawners achieved significantly higher number of eggs per spawn, number of egg per spawn per g of spawner's body weight and number of nauplii per spawn (P < 0.05). Latency period was significantly shorter (P < 0.05) for wild than for domesticated females (11 vs 17 days). Wild spawners also presented less mortality (6 vs 12%), higher number of total spawns (51 vs 33), spawns per ablated and per spawning females as well as higher total eggs and nauplii production. On the other hand, domesticated females presented higher number of females that spawned at least once (89 vs 76%). The higher spawning activity was reflected in lower levels of acylglycerides (AG) and cholesterol content in wild hepatopancreas (HP) and ovary (OV) (P < 0.05). FA profile, mainly represented by ARA, EPA and sum of n − 3 were higher in hepatopancreas and ovary of wild females, however lower levels were detected in eggs as a result of a high spawning activity. Multivariate analysis performed to detected simultaneous variation in biochemical variables indicated AG as variation pattern's responsive.
The effects of different diets on spermatophore production and sperm quality were investigated in the river prawn Macrobrachium americanum. River prawns were cultured and fed with three diets for 244 days: fresh food (50% squid meat, Dosidicus gigas and 50% sardine muscle, Sardinops sagax); commercial pellets (35 Purina®); and a 50:50 mixture of both diets. Spermatophore production was recorded every 24 days on average as the percentage of spermatophores produced per extraction per diet, weight and biochemical composition. Sperm quality was measured as the total number of sperm, the proportion of live/dead sperm and normal/abnormal sperm morphology. There were no significant differences in the mean biochemical composition of M. americanum spermatophores for any of the diets. Biochemical composition was 36.3% protein, 25.8% carbohydrate and 4.6% lipids for all data pooled. The weight of spermatophores and sperm counts was not significantly different among diets, nor were there any differences as a function of the male initial total length (p > .05). Male river prawn reproductive exhaustion was observed as a decline in spermatophore production, weight of the spermatophores and the number of sperm cells per spermatophore, with an increasing proportion of dead and abnormal sperm seen throughout the experiment. The recommended period of maintenance in captivity for male broodstock is less than 115 days. It is recommended to feed broodstock males of M. americanum with commercial pellets because no significant differences were detected with the diets tested; pellets are easier to use, ensuring the same spermatophore production and sperm quality that was obtained with fresh food.
Changes in metabolite levels in hemolymph and hepatopancreas were used as indicators of physiological status of juvenile wild and cultivated Farfantepenaeus duorarum (Burkenroad, 1939), during hyper-osmoregulatory conditions (salinity 22 ppt, 726 mOsm/kg). We analyzed the relationship between biochemical changes of wild and cultivated shrimp at different molt stages by measurement of osmotic capacity, hemocyanin, acylglycerides, cholesterol, glucose, glycogen and total protein. Biochemical analyses of hemolymph (blood) and hepatopancreas showed a decreasing trend in stages closer to molt and an increasing trend before intermolt. Osmotic capacity and blood proteins indicated a significant effect of the molt stage. Stages A, D1 and D1 showed the greatest effect on the biochemical variables. Higher hemocyanin, cholesterol and glycogen concentrations were observed in wild shrimp than in cultivated shrimp. The effect of the molt cycle was associated with changes in cyclic ions and water balance that produced chemical changes in the hemolymph in both wild and cultivated.
Growth patterns and biochemical analysis at laboratory conditions (temperature 28 degrees C, salinity 22) were analyzed in juveniles wild pink shrimp, Farfantepenaeus duorarum (Burkenroad, 1939), caught in the Gulf of Mexico compared with cultivated (F2) organisms. Shrimp were maintained for 55 days to monitor the molt frequency and weight gain over time. We determined the frequency of molting and wet weight gain per day over the experiment time. Wild shrimp had an average molting frequency of 10 +/- 2.03 days with an increase in wet weight of 0.024 +/- 0.001 g day(-1); whereas cultivated shrimp had an average frequency of 11 +/- 2.15 days and a growth rate of 0.084 +/- 0.002 g day(-1). Osmotic capacity was determined in wild shrimp at 154.85 +/- 73.47 mOsm kg(-1) and for cultivated at 128.67 +/- 42.24 mOsm kg(-1). Total protein concentration was 35.15 mg ml(-1) for wild shrimp, while values for cultivated shrimp were significantly different at 112.22 mg ml(-1) (ANOVA; p < 0.05). Also, an experiment was conducted to determine the amount of food consumed before and after ecdysis in wild and cultivated shrimp. No significant differences were found in the food consumption (F = 0.220, p = 0.641) between groups before and after ecdysis. We determined that food consumption rate fell by 30% during molt and that feeding did not cease when ecdysis occurs.
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