RESUMEN
The selected chemical composition (dry matter, ash, total protein, and crude fat) of the integumentary muscles of Dendrobaena veneta were determined, plus the dry matter (DM) percentage content of 17 amino acids and the profile (%) of fatty acids. Results were compared with a more fully studied earthworm, Eisenia fetida. In addition, the composition of exogenous amino acids was compared to the WHO standard for pork, beef, and chicken eggs. Both earthworm species were grown on the same kitchen waste, and protein composition was analyzed using the same methods. Studies indicated that the muscle of D. veneta was characterized by a high level of protein (76.82% DM). A similar content of exogenous amino acids was observed in the protein of both earthworms, but for phenylalanine and isoleucine, slightly higher levels were recorded for E. fetida. More histidine, lysine, threonine, isoleucine, and arginine were found in earthworms compared with chicken egg white. Fatty acids play an essential role in balancing human or animal feed and their content determines the dietary and nutritional value of the food. Both earthworm species contained the appropriate content of saturated and unsaturated acids. In D. veneta, a higher content of arachidonic acid was found, and in E. fetida, lauric, tridecanoic, and palmitic acids were present. Future issues of food security may force us to seriously consider earthworm protein for indirect or even direct human consumption.
Asunto(s)
Oligoquetos , Rosa , Animales , Bovinos , Humanos , Oligoquetos/metabolismo , Biomasa , Isoleucina/metabolismo , Proteínas , Aminoácidos/metabolismo , Ácidos Grasos/metabolismoRESUMEN
This work relates data from field sampling of Eisenia lucens and from laboratory-based culture. Field sampling used soil sorting and vermifuge extraction and took place in beech-dominated forests of southwest Poland. Initial work derived population estimates from four sub-communities of the forest looking for seasonal dynamics and later work employed targeted sampling in summer within rotting wood to obtain live specimens for laboratory culture. A preliminary examination within and below rotten wood during winter was also undertaken. In the laboratory, clitellate earthworms were kept at 20 °C, the substrate changed every 6 months, and the population examined. Cocoons were incubated individually at 15 °C, with number of hatchlings per cocoon and the mass of each determined. Hatchlings were grown at 15 °C in field-collected wood and compared with growth in a 1:1 volume ratio of wood and horse manure. Further hatchlings were fed with horse manure only (at 10 °C) and after 19 weeks, half were transferred to 15 °C. In the field, mature individuals varied significantly (p < 0.01) in biomass between 2 sampling sites where found, with an overall mean density across sites of 4.14 ± 3.53 m-2 with a mean biomass of 2.21 ± 1.93 g m-2. Numbers in soil varied over the sampling period, with a suggestion that this species moves from mineral soil to organic-rich dead wood as conditions permit. In summer, all life stages were recovered from rotting wood above the mineral soil. Sampling in winter found cocoons in rotting wood below snow. These hatched rapidly (within 2 weeks) when taken to the laboratory. Laboratory culture allowed maintenance of a population for 2 years. Mean cocoon mass was 50.6 mg with a mean of 2.9 hatchlings per cocoon and hatchling mass was inversely proportional to number per cocoon. Growth with 50% horse manure was significantly greater (p < 0.001) than with wood. Increased temperature from 10 to 15 °C brought more significantly (p < 0.05) rapid growth. To culture this species through its life cycle, a natural substrate is needed, but then it is necessary to acclimate the animals to something more easily obtainable. More work is needed from field sampling to fully understand the seasonal dynamics of this species, which utilises different parts of the soil profile throughout the year.