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... (Jory, 2001) Las proteínas son nutrientes esenciales y limitantes para el crecimiento de los ... more ... (Jory, 2001) Las proteínas son nutrientes esenciales y limitantes para el crecimiento de los camarones ... vegetal también es utilizada por su calidad demostrada (Smith et al., 2000; Cruz Suárez et ... 1 Elaborada en el Laboratorio de organismos obtenidos de la pesquería comercial ...
The feasibility of substituting soybean meal for ¢sh-meal diets for juvenile white shrimp Litopen... more The feasibility of substituting soybean meal for ¢sh-meal diets for juvenile white shrimp Litopenaeus schmitti (0.35 AE 0.01g) was evaluated, and an adequate substitution level was determined. Five diets were evaluated using 46%, 59%, 75%, 88% and 100% substitution levels. Pellet water stability was signi¢cantly a¡ected by dietary soybean content (Po0.05). Increased soybean content produced lower pellet stability, ranging from a dry matter loss of 14^ 22% after a 2-h immersion, and 20^33% after an 8-h immersion. After 52 days, signi¢cant di¡erences (Po0.05) were found in shrimp weight, feed conversion ratio and protein e⁄ciency ratio. The values were 0.64^1.06 g, 2.8^7.9 and 0.45^1.21, respectively, for the three measurements. Overall, better results were obtained with diets where soybean meal was substituted for ¢shmeal up to 75%. The 100% soybean meal diet resulted in poor growth performance of shrimp. Survival rates were acceptable for all treatments (90% or higher) and no signi¢cant di¡erences were found in survival between treatments. Regression analysis using the broken-line methodology indicated that 76.5 AE 2% is an optimum soybean substitution level in diets that contained ¢shmeal and soybean as the major protein sources for grow-out of juvenile white shrimp.
RESUMEN Para evaluar el efecto de diferentes niveles de proteína y densidades de siembra sobre el... more RESUMEN Para evaluar el efecto de diferentes niveles de proteína y densidades de siembra sobre el crecimiento de juveniles de camarón Litopenaeus schmitti (0.18+0.03 g de peso inicial medio), se desarrolló un diseño experimental totalmente aleatorizado en estanque de tierra durante 72 días, con 16 tratamientos y 3 repeticiones, combinando 3 niveles de proteína (28, 30 y 35 %) y
Journal of Experimental Biology, 2012
The effects of pelleted diets with different protein composition (fish, squid or soybean meals as... more The effects of pelleted diets with different protein composition (fish, squid or soybean meals as main protein sources) on trypsin secretion and expression were studied in the lobster Panulirus argus. Trypsin secretion was shown to be maximal 4 h after ingestion. At this time, fish- and squid-based diets induced trypsin secretion, as well as up-regulation of the major trypsin isoform at the transcription level. While fish- and squid-based diets elicited a prandial response, soybean-based diet failed to stimulate the digestive gland to secrete trypsin into the gastric fluid or induce trypsin expression above the levels observed in fasting lobsters. In vitro assays showed that intact proteins rather than protein hydrolysates stimulate trypsin secretion in the lobster. However, the signal for trypsin transcription appears to be different to that for secretion and is probably mediated by the appearance of free amino acids in the digestive gland, suggesting a stepwise regulation of trypsin enzymes during digestion. We conclude that trypsin enzymes in P. argus are regulated at the transcription and secretion level by the quality of dietary proteins through two distinct signaling pathways. Our results indicate that protein digestion efficiency in spiny lobsters can be improved by selecting appropriated protein sources. However, other factors like the poor solubility of dietary proteins in dry diets could hamper further enhancement of digestion efficiency.
A completely aleatory desing was prepared with 9 treatments and 3 replicas in fiberglass containe... more A completely aleatory desing was prepared with 9 treatments and 3 replicas in fiberglass containers 100 l. of volume and initial density of 150 nauplii/l. in order to evaluate the affect of different species of dry microalgas (Spirulina platensis, from Cuba and USA; Chlorella sp. and Dunaliella salina) on the feeding of protozoea of white shrimp Penaeus schmitti in culture,
Aquaculture, 2007
Spiny lobsters are prevalent in tropical and temperate seas and support some of the largest comme... more Spiny lobsters are prevalent in tropical and temperate seas and support some of the largest commercial fisheries in the world. Studies on the metabolic rate of spiny lobsters contribute to the understanding of the relation of these widely distributed crustaceans with their environment, to the design of holding facilities and to the development of future aquaculture technologies. The current study
Aquaculture Research, 2007
... (Jory, 2001) Las proteínas son nutrientes esenciales y limitantes para el crecimiento de los ... more ... (Jory, 2001) Las proteínas son nutrientes esenciales y limitantes para el crecimiento de los camarones ... vegetal también es utilizada por su calidad demostrada (Smith et al., 2000; Cruz Suárez et ... 1 Elaborada en el Laboratorio de organismos obtenidos de la pesquería comercial ...
The feasibility of substituting soybean meal for ¢sh-meal diets for juvenile white shrimp Litopen... more The feasibility of substituting soybean meal for ¢sh-meal diets for juvenile white shrimp Litopenaeus schmitti (0.35 AE 0.01g) was evaluated, and an adequate substitution level was determined. Five diets were evaluated using 46%, 59%, 75%, 88% and 100% substitution levels. Pellet water stability was signi¢cantly a¡ected by dietary soybean content (Po0.05). Increased soybean content produced lower pellet stability, ranging from a dry matter loss of 14^ 22% after a 2-h immersion, and 20^33% after an 8-h immersion. After 52 days, signi¢cant di¡erences (Po0.05) were found in shrimp weight, feed conversion ratio and protein e⁄ciency ratio. The values were 0.64^1.06 g, 2.8^7.9 and 0.45^1.21, respectively, for the three measurements. Overall, better results were obtained with diets where soybean meal was substituted for ¢shmeal up to 75%. The 100% soybean meal diet resulted in poor growth performance of shrimp. Survival rates were acceptable for all treatments (90% or higher) and no signi¢cant di¡erences were found in survival between treatments. Regression analysis using the broken-line methodology indicated that 76.5 AE 2% is an optimum soybean substitution level in diets that contained ¢shmeal and soybean as the major protein sources for grow-out of juvenile white shrimp.
RESUMEN Para evaluar el efecto de diferentes niveles de proteína y densidades de siembra sobre el... more RESUMEN Para evaluar el efecto de diferentes niveles de proteína y densidades de siembra sobre el crecimiento de juveniles de camarón Litopenaeus schmitti (0.18+0.03 g de peso inicial medio), se desarrolló un diseño experimental totalmente aleatorizado en estanque de tierra durante 72 días, con 16 tratamientos y 3 repeticiones, combinando 3 niveles de proteína (28, 30 y 35 %) y
Journal of Experimental Biology, 2012
The effects of pelleted diets with different protein composition (fish, squid or soybean meals as... more The effects of pelleted diets with different protein composition (fish, squid or soybean meals as main protein sources) on trypsin secretion and expression were studied in the lobster Panulirus argus. Trypsin secretion was shown to be maximal 4 h after ingestion. At this time, fish- and squid-based diets induced trypsin secretion, as well as up-regulation of the major trypsin isoform at the transcription level. While fish- and squid-based diets elicited a prandial response, soybean-based diet failed to stimulate the digestive gland to secrete trypsin into the gastric fluid or induce trypsin expression above the levels observed in fasting lobsters. In vitro assays showed that intact proteins rather than protein hydrolysates stimulate trypsin secretion in the lobster. However, the signal for trypsin transcription appears to be different to that for secretion and is probably mediated by the appearance of free amino acids in the digestive gland, suggesting a stepwise regulation of trypsin enzymes during digestion. We conclude that trypsin enzymes in P. argus are regulated at the transcription and secretion level by the quality of dietary proteins through two distinct signaling pathways. Our results indicate that protein digestion efficiency in spiny lobsters can be improved by selecting appropriated protein sources. However, other factors like the poor solubility of dietary proteins in dry diets could hamper further enhancement of digestion efficiency.
A completely aleatory desing was prepared with 9 treatments and 3 replicas in fiberglass containe... more A completely aleatory desing was prepared with 9 treatments and 3 replicas in fiberglass containers 100 l. of volume and initial density of 150 nauplii/l. in order to evaluate the affect of different species of dry microalgas (Spirulina platensis, from Cuba and USA; Chlorella sp. and Dunaliella salina) on the feeding of protozoea of white shrimp Penaeus schmitti in culture,
Aquaculture, 2007
Spiny lobsters are prevalent in tropical and temperate seas and support some of the largest comme... more Spiny lobsters are prevalent in tropical and temperate seas and support some of the largest commercial fisheries in the world. Studies on the metabolic rate of spiny lobsters contribute to the understanding of the relation of these widely distributed crustaceans with their environment, to the design of holding facilities and to the development of future aquaculture technologies. The current study
Aquaculture Research, 2007