Utilization of rice byproducts as carbon sources in high-density culture of the Pacific white shrimp, Litopenaeus vannamei

This study was conducted to evaluate the effect of rice byproducts on water quality, microbial community, and growth performance of L. vannamei juveniles. Shrimp of 0.98±0.10 g body weight (BW) were reared in 49 tanks of 1.5 m3 under 127 animals m−2 for 77 days. Rice bran, rice grits, and rice hulls were mixed into five different fertilizers varying their fiber content (90, 110, 150, 200, and 250 g kg−1) and compared against sugarcane molasses (MO) and unfertilized tanks (UNF). Rice byproducts and MO were applied in water three times a week at a fixed rate of 4.5 g m−3. Water salinity, pH, temperature, and dissolved oxygen reached 43±2 g L−1, 8.03±0.32, 30.2±0.90 °C, and 5.03±0.53 mg L−1, respectively. Settleable solids (SS) were higher in tanks fertilized with rice byproducts (from 2.5±1.0 to 3.1±1.1 mL L−1) and MO (3.4±1.0 mL L−1). Total ammonia nitrogen (0.19±0.09 mg L−1), nitrite (5.97±2.04 mg L−1), and nitrate (1.29±0.48 mg L−1) were kept low without any significant differences among treatments. The concentration of heterotrophic bacteria and fungi was significantly higher in rice byproducts compared with MO. Water fertilization had no effect on final shrimp survival (85.5±9.5%), weekly growth (0.72±0.11 g), and feed conversion ratio (1.59±0.10). Tanks treated with rice byproducts, except with 90 g kg−1 fiber, resulted in a higher final shrimp BW (from 9.04±1.56 to 9.52±1.89 g) compared with MO (8.75±2.14 g) and UNF (7.74±1.48 g). Gained yield and feed intake were significantly higher for tanks treated with rice byproducts than with UNF. A mix of rice byproducts can be equally or more effective as carbon sources to shrimp culture than MO.(AU)

Dose inseminante e embriogênese na fertilização assistida de carpa comum no nordeste brasileiro / Inseminating dose and embryogenesis in assisted fertilization of common carp in northeastern of Brazil

A presente pesquisa visou determinar a dose inseminante para a fertilização assistida da carpa comum, e o registro em imagens e o tempo de desenvolvimento de cada fase embrionária desta espécie em latitude equatorial. Verificou-se que a porcentagem de fertilização aumentou de forma linear, atingindo um platô em 45,5% na proporção de 208.295 espermatozoides/oócito. Assim, recomenda-se o uso da dose inseminante de aproximadamente 200.000 espermatozoides/oócito na rotina de fertilização assistida dessa espécie, no nordeste brasileiro. Além disso, o desenvolvimento embrionário da carpa em latitude equatorial segue a cronologia semelhante ao relatado para a espécie em clima temperado.(AU)

The present research aimed at determining insemination dose for artificial fertilization of common carp, and record images and time in the development of each embryonic stage of the species in equatorial latitude. The fertilization rate increased linearly up to the proportion of 208.295 spermatozoa/oocyte, and, from this point, the fertilization rate was maintained at 45.5%. Therefore, we recommend the use of the insemination dose of approximately 200.000 sperm/oocyte in the artificial fertilization routine of common carpin brazilian northeast. Moreover, embryonic development of carp in equatorial latitude follows the chronology similar to that reported for the species in temperate zones.(AU)

Dose inseminante e embriogênese na fertilização assistida de carpa comum no nordeste brasileiro / Inseminating dose and embryogenesis in assisted fertilization of common carp in northeastern of Brazil

A presente pesquisa visou determinar a dose inseminante para a fertilização assistida da carpa comum, e o registro em imagens e o tempo de desenvolvimento de cada fase embrionária desta espécie em latitude equatorial. Verificou-se que a porcentagem de fertilização aumentou de forma linear, atingindo um platô em 45,5% na proporção de 208.295 espermatozoides/oócito. Assim, recomenda-se o uso da dose inseminante de aproximadamente 200.000 espermatozoides/oócito na rotina de fertilização assistida dessa espécie, no nordeste brasileiro. Além disso, o desenvolvimento embrionário da carpa em latitude equatorial segue a cronologia semelhante ao relatado para a espécie em clima temperado.

The present research aimed at determining insemination dose for artificial fertilization of common carp, and record images and time in the development of each embryonic stage of the species in equatorial latitude. The fertilization rate increased linearly up to the proportion of 208.295 spermatozoa/oocyte, and, from this point, the fertilization rate was maintained at 45.5%. Therefore, we recommend the use of the insemination dose of approximately 200.000 sperm/oocyte in the artificial fertilization routine of common carpin brazilian northeast. Moreover, embryonic development of carp in equatorial latitude follows the chronology similar to that reported for the species in temperate zones.