ABSTRACT Soil fauna is an essential component of the soil ecosystem for maintaining nutrient cycling and biological soil fertility. This study assessed the soil biodiversity (macrofauna, mesofauna, and microfauna) to define strategies for the sustainable management of tropical agricultural soils. The study was carried out in 200 agricultural production units in the Department of Sucre, in northern Colombia. Physicochemical properties (organic matter, nitrogen, phosphorus, and pH) were determined for each soil sample. The Berlesse-Tullgren method was used to determine the composition of macrofauna and mesofauna, while the sown surface plate counting method was applied for microfauna. Community biodiversity was quantified with diversity indices, and Pearson correlation was carried out to determine the relationships between soil fauna and soil quality indicators. For the macrofauna, 1330 individuals were found, distributed in 22 orders and 65 families; the families Tenebrionidae, Formicidae, Staphylinidae, Scarabaeidae and Julide presented the highest abundance and distribution. Mesofauna presented 1,171 individuals, distributed in the classes Arachnida with seven families and Collembola with four families; the Scheloribatidae, Isotomidae and Galumnidae families presented the highest abundance and distribution. The indices of richness, Shannon-Wiener diversity and Simpson dominance indicated that biodiversity was higher for macrofauna. Pearson’s correlation indicated significant correlations between soil mesofauna and soil organic matter (R2 = 0.87; p≤0.05) and phosphorous (R2 = 0.70; p≤0.05). The relationships between fauna and soil chemical properties indicate that soil biological diversity is sensitive to changes in the soil environment. This study revealed the importance of investigating the three components of soil fauna (macrofauna, mesofauna, and microfauna), since all three contribute to soil enrichment to grow nourished crops that allow plants to survive under climate change. Finally, this study may serve as a baseline to define strategies for sustainable management of tropical agricultural soils.

Resumo O objetivo deste trabalho foi avaliar o efeito crioprotetor de embalagens a vácuo (35 e 45 kPa) em filés de Yamú (Brycon amazonicus) conservados a frio (0 °C e -18 °C), durante cinco dias de armazenamento. As alterações físico-químicas e microbiológicas foram analisadas nos filés durante o armazenamento. A capacidade de retenção de água, o teor de base nitrogenada (BTV-N) e a textura (N) foram influenciados (p ≤ 0,05) pelo tempo e pela temperatura. Colônias bacterianas em filés não representaram risco à saúde humana após cinco dias de armazenamento. O uso de embalagem a vácuo apresentou efeito significativo positivo (p ≤ 0,05), reduzindo o efeito do frio sobre as propriedades dos filés.

Abstract This study aimed to assess the cryoprotectant effect of vacuum packaging (35 and 45 kPa) on cold preserved (0 °C and -18 °C) fillets of Yamú (Brycon amazonicus), during 5 days of storage. We analyzed the physicochemical and microbiological changes in the fillets during storage time. Yamú’s water holding capacity, nitrogenated bases content (TVB-N) and texture (N) were affected (p ≤ 0.05) by time and temperature. Bacterial colonies in fillets did not represent a risk for human health after five days of storage. In conclusion, vacuum packing positively (p ≤ 0.05) reduces the effect of cold over Yamú fillets properties.

Abstract The objective of this research was to evaluate the effect of individual genetic variability of spawners in the procurement (production and genetic quality) of Prochilodus magdalenae larvae, used in the repopulation programs in the Magdalena river (Colombia). The spawners system was used based on the genetic criteria of the Centro Acuícola y Agroindustrial de Gaira (SENA Magdalena, Colombia), forming groups with different levels of individual heterozygosity (Ho<=0.3; 0.3>Ho<=0.6 y Ho>0.6). The hormonal induction was done with Pituitary Carp Extract (PCE) using a dosage of 6.6 mg/Kg. The production parameters in the different levels of heterozygosity were measured, such as weight, fertility, fertilization rate, hatching and survival rate. The larvae obtained were fixed in alcohol at 96% for the genetic analyses performed through the use of seven loci micro-satellites. There were significant differences between the individual heterozygosity intervals both in the production parameters and in the genetic quality of the obtained progenies (p < 0.05). A decrease was detected in the heterozygosity observed in the obtained progenies (Ho=0.198, 0.203, 0.392) compared to the heterozygosity of the spawners (Ho=0.190, 0.444, 0.730) for the three intervals of heterozygosity evaluated. The parameters of weight production, fertilization rate and survival, as well as the genetic quality in terms of Ho and Fis of the obtained progenies, are positively related with the genetic variability of the spawners. It is therefore advised that in order to implement breeding programs, spawners with individual heterozygosity values above 0.6 are used for the production of larvae destined to the repopulation of natural communities of P. magdalenae.

Resumen El objetivo de esta investigación consistió en evaluar el efecto de la variabilidad genética individual de los reproductores en la obtención (producción y calidad genética) de larvas de bocachico (Prochilodus magdalenae) usadas en los programas de repoblamiento en el río Magdalena (Colombia). Se utilizó el sistema de reproductores con criterio genético del Centro Acuícola y Agroindustrial de Gaira (SENA Magdalena, Colombia), conformando grupos con diferentes niveles de heterocigosidad individual (Ho<=0.3; 0.3>Ho<=0.6 y Ho>0.6), la inducción hormonal fue realizada con Extracto Pituitario de Carpa (EPC) a una dosis de 6.6 mg/Kg. Se midieron parámetros de producción en los diferentes niveles de heterocigosidad tales como peso, fecundidad, tasa de fertilización, tasa de eclosión y supervivencia. Las larvas obtenidas fueron fijadas en alcohol al 96% para los análisis genéticos a través del uso de siete loci microsatélites. Hubo diferencias significativas entre los intervalos de heterocigosidad individual tanto en los parámetros de producción como en la calidad genética de las progenies obtenidas (p < 0.05). Se observó una disminución de la heterocigosidad observada en las progenies obtenidas (Ho=0.198, 0.203, 0.392) en comparación con la heterocigosidad de los reproductores (Ho=0.190, 0.444, 0.730) para los tres intervalos de heterocigosidad evaluados. Los parámetros de producción de peso, tasa de fertilización y supervivencia; así como la calidad genética en términos de Ho y Fis de las progenies obtenidas, están relacionados positivamente con la variabilidad genética de los reproductores, por lo que se recomienda que para implementar programas de crianza, se utilicen reproductores con valores de heterocigosidad individual superiores a 0.6 para la producción de larvas destinadas al repoblamiento de poblaciones naturales de P. magdalenae.