Apolinar Santamaría-Miranda

Hábitos alimenticios del pargo amarillo Lutjanus argentiventris y del pargo rojo Lutjanus colorado (Pisces: Lutjanidae) en el norte de Sinaloa, México

La biologia y ecologia de las especies Lutjanus colorado y Lutjanus argentiventris son poco conocidas en el estado de Sinaloa, Mexico a pesar de la importancia economica que tiene, con capturas de 233.642 tm en el 2000. Estomagos de estas especies fueron recolectados mensualmente durante el ano 2001, a partir de organismos capturados tanto por la flota comercial riberena como durante la realizacion de salidas de campo propias. Se analizaron 145 estomagos de L. argentiventris y 87 de L. colorado. Las presas presentes en los contenidos estomacales fueron identificadas, clasificadas, numeradas y pesadas. Para el analisis cuantitativo del regimen alimenticio de las especies se calcularon los porcentajes en numero y peso de las presas asi como el indice de importancia relativa (IIR) total, mensual, por sexos y por tallas. La dieta de los peces estuvo constituida por dos grupos troficos principales: peces y crustaceos. La presa mas importante en la dieta de L. argentiventris fue Penaeus sp. (Decapoda Natantia) y en la de L. colorado, fue Goniopsis pulchra (Decapoda Reptantia). La cantidad de presas consumidas se incremento en los meses de verano, observandose durante este periodo una mayor variedad del espectro alimenticio. Se utilizo el porcentaje en numero y en peso para determinar la diversidad del espectro alimentario. Se encontro que estos valores fueron bajos (<0,5), determinandose que la dieta de estas especies de pargos es de baja diversidad pero abundante.

Growth and metabolic responses of whiteleg shrimp Litopenaeus vannamei and Nile tilapia Oreochromis niloticus in polyculture fed with potential probiotic microorganisms on different schedules

ABSTRACT. Probiotics and co-culture of shrimp and tilapia are two strategies to improve yield and eco-efficiency of both species. However, only few studies have analyzed the combination of these two strategies. This study analyzes the effect of a mixture of potential probiotics supplied in the diet at different frequencies in a system of shrimp (10 m -2 ) and tilapia (5 m -2 ) in a trial lasting 84 days. The probiotics mixture was composed of four lactic acid bacteria and one yeast strain that were supplied either daily, every 5 days, or every 10 days in the diet and compared with a control without any supply of probiotics. At the end of the experiment, blood chemistry and hematology of shrimp and tilapia were analyzed as an index of physiological condition. Water quality did not differ between treatments. The final weight, feed conversion ratio, and yield of shrimp were significantly higher with daily supply of probiotics compared to shrimp that did not receive probiotics supply, with intermediate values for treatments with probiotics supply every 5 or 10 days. However, level of supplementation every 5 days could be considered as optimal because no significant differences with daily supply were observed for any variable, whereas the supply each 10 days resulted in a significantly lower yield. Significantly higher final weight, feed conversion ratio, and yield of tilapia occurred with daily supplements. Blood cholesterol in tilapia significantly decreased with increasing frequency of probiotics supplementation. These results indicate that probiotics supplements for shrimp and tilapia cultivated simultaneously improved yields and physiological condition.

Effect of temperature on the morphometric development of eggs in the prawn Macrobrachium americanum (Caridea: Palaemonidae) and larval success under experimental conditions

Abstract This study evaluated the effect of temperature on morphometric features of the egg during the embryonic development of the prawn Macrobrachium americanum and the relationship with hatching and the survival of the larvae. Berried females were grouped (n = 3) and reared at three different temperatures, 26, 29, and 33 °C, for which seven developmental stages were recognized. At each stage, the apical and sagittal diameters of the eggs were measured, the volume was calculated, and the weights were recorded. Additionally, the duration of embryonic development, hatching percentage, and larval survival were determined. At 29 and 33 °C, the eggs’ volume increased by 50%, but at 26 °C, the increase was 25%. Larvae from eggs incubated at 33 °C died one day after hatching. At 29 °C, larvae survived until Zoea VII. Larvae from eggs incubated at 26 °C died at the end of Zoea I. The number of days of embryonic development was 20.5 ± 1.5 (26 °C), 15 ± 1 (29 °C), and 12 ± 1 (33 °C). A temperature of 29 °C was the most favorable for embryonic development in M. americanum.

Respuesta de metabolitos en hemolinfa y desempeño productivo del camarón blanco del Pacífico Litopenaeus vannamei cultivado a altas densidades en laboratorio

In shrimp farming, one of the most important challenges is to increase shrimp production, which has encouraged increased seeding rates. In this study, the response of metabolites in hemolymph and performance of white shrimp (Litopenaeus vannamei) grown at high densities was evaluated, using total protein, lactate and glucose concentrations as stress indicators. At the beginning of the bioassay, lactate was high, while growth and specific survival were poorer, which is inferred as a response to seeding- time stress. At the end of the bioassay was obtained statistical difference in total protein levels, with an increase of final weight and survival.