Tenebrio molitor (Coleoptera: Tenebrionidae)-Optimization of Rearing Conditions to Obtain Desired Nutritional Values.

The present study dealt with the influence of temperature and feed on the nutritional value of Tenebrio molitor, especially on the content of crude protein, amino acids, fat, and fatty acid profile. Tenebrio molitor larvae were kept in 15, 20, and 25°C and fed with wheat bran, lentil flour, and mixture. The parameters were analyzed by international standard methods. Generally, with an increase of the lentils in the feed, the crude protein content increased. The changes in the temperature and the feed were most pronounced on the essential amino acids Val, Arg, and Leu. The highest average fat content was determined at 20°C in insects fed with wheat bran. The lowest fat content was determined at 15°C in bran-fed insects. The dependency of fat content on the temperature in feeding with lentil flour and a mixture of wheat bran and lentil flour was statistically insignificant (P > 0.05, Kruskal-Wallis, Mann-Whitney post hoc tests). The highest content of polyene fatty acids was achieved at a rearing temperature of 15°C and the bran diet. It was concluded that a higher proportion of protein diet could increase the content of crude protein in the insects. An increase in the temperature generally leads only to a slight increase in the content of nitrogenous substances. The influence of feed on this nutritional parameter is therefore much more significant than the effect of the rearing temperature. In general, it can be stated that the feed and the temperature also significantly affect the fat content.

Effect of Accumulation of Heavy Metals in the Red Fox Intestine on the Prevalence of Its Intestinal Parasites.

The aim of this study was (i) to compare levels of accumulated heavy metals in the fox intestines with and without parasites. Moreover, our research also dealt with (ii) examination of the relationship between heavy metal content in fox intestines and between the presence of fox intestinal parasites. The intestines of 34 hunter-killed foxes were dissected to detect the occurrence of parasites. In 15 intestinal samples, parasitic intestinal helminths were found. Heavy metal content in small intestine tissue and in parasites was determined using atomic absorption spectrometry (AAS). The prevalence of parasites was significantly dependent on Cd content in the host's small intestine (p < 0.01). To conclude, the authors suggest that parasites are sensitive to Cd levels; their prevalence in the intestines of the fox host decreases to zero with increasing Cd content.

To eat or get heat: Behavioral trade-offs between thermoregulation and feeding in gregarious necrophagous larvae.

The thermoregulation behavior of Lucilia sericata larvae (Diptera: Calliphoridae), a necrophagous species that feeds on vertebrate cadavers, was investigated. These larvae require high heat incomes to develop, and can elevate temperatures by forming large aggregates. We hypothesized that L. sericata larvae should continue to feed at temperatures up to 38 °C, which can be reached inside larval masses. Thermal regulation behavior such as movement between a hot food spot and colder areas was also postulated. The hypotheses were tested by tracking for 1 h the activity of single, starved third instar larvae in a Petri dish containing 1 food spot (FS) that was heated to a constant temperature of 25 °C, 34 °C or 38 °C with an ambient temperature of 25 °C. The influence of previous conspecific activity in the food on larval behavior was also tested. The crops of larvae were dissected to monitor food content in the digestive systems. Based on relative crop measurements, larvae fed at all food temperatures, but temperature strongly affected larval behavior and kinematics. The total time spent by larvae in FS and the duration of each stay decreased at high FS temperature. Previous activity of conspecifics in the food slightly increased the time spent by larvae in FS and also decreased the average distance to FS. Therefore, necrophagous L. sericata larvae likely thermoregulate during normal feeding activities by adjusting to local fluctuations in temperature, particularly inside maggot masses. By maintaining a steady internal body temperature, larvae likely reduce their development time.

Nutritional Potential of Selected Insect Species Reared on the Island of Sumatra.

Inhabitants of the Indonesian island of Sumatra are faced with the problem of insufficient food supplies and the consequent risk of undernourishment and health issues. Edible insects as a traditional and readily available food source could be part of the solution. The nutritional value of insects depends on many factors, e.g., species, developmental stage, sex, diet, and climatic conditions. However, edible insects bred in Sumatra for human consumption have never before been assessed with regard to their nutritional value. Our study involved analyses of crude protein, chitin, fat and selected fatty acid contents of giant mealworm larvae (Zophobas morio), larvae of the common mealworm (Tenebrio molitor) and nymphs of the field cricket (Gryllus assimilis). Crude protein content in the samples ranged from 46% to 56%. Highest (35%) and lowest (31%) amounts of fat were recorded in giant mealworm larvae and larvae of the common mealworm, respectively. Chitin amounts ranged from 6% to 13%. Based on these values, which are comparable to those known from other food insects reared in different regions of the world, the edible species bred in Sumatra could become food sources with a potential to help stave off hunger and undernourishment.

Purine derivate content and amino acid profile in larval stages of three edible insects.

BACKGROUND: Considering their high content of protein, insects are a valuable alternative protein source. However, no evaluation of their purine content has so far been done. High content of purine derivates may lead to the exclusion of such food from the diet of people with specific diseases. The aim of this study was to analyse the content of selected purine derivates and amino acid profile in the three insect species most often used for entomophagy in Europe and compare them with the purine content in egg white and chicken breast. RESULTS: The content of individual purine derivates and their total content were significantly dependent on insect species. The purine content in all three species was significantly higher (P < 0.05) than in egg white, but some values were significantly lower (P < 0.05) than in chicken breast. The total protein content was 548.9 g kg(-1) dry matter (DM) in mealworm (Tenebrio molitor), 551.6 g kg(-1) DM in superworm (Zophobas atratus) and 564.9 g kg(-1) DM in cricket (Gryllus assimilis). CONCLUSION: Larvae of mealworm and superworm are protein-rich and purine-low meat alternatives. In contrast, cricket nymphs are protein-rich and purine-rich and cannot be recommended for people with hyperuricemia or gout.

Thermal profile of rabbits infected with Eimeria intestinalis.

In this study, infrared thermography (IRT) was assessed as a means of detecting the changes in body temperature in rabbit coccidiosis, as well as determining IRT used in imaging and measuring the regional changes in skin temperature that occur in the rabbits during this infection. Rabbits were inoculated with 5 x 10(4) or 1 x 10(5) oocysts of Eimeria intestinalis, respectively. The group of control animals remained non-inoculated throughout the study. All measured temperatures (rectal, ocular surface and auricle pavilion temperatures) dropped significantly (P<0.05) in rabbits infected with 1 x 10(5) oocysts. This group of rabbits also showed a medium negative correlation in rectal temperature (r=-0.49), ocular surface temperature (r=-0.49) and auricle pavilion temperature (r=-0.49) and a small negative correlation in live body weight gain (r=-0.22) depending on the number of days elapsed from the time of infection exposure.

Linear distribution of nematodes in the gastrointestinal tract of tracer lambs.

Forty-eight tracer lambs were killed in 2004-2007. The abomasum, duodenum, small intestine (jejunum and ileum), colon and caecum were collected and processed for parasites enumeration and identification-mucosal scrapings of both abomasums and intestines were digested. Out of 48 gastrointestinal tracts examined, all were found to be positive for nematode infection. Seventeen species of gastrointestinal nematodes were recovered: Bunostomum trigonocephalum, Cooperia curticei, Haemonchus contortus, Chabertia ovina, Nematodirus battus, Nematodirus filicollis, Oesophagostomum venulosum, Teladorsagia circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Strongyloides papillosus, Trichuris ovis, Trichuris globulosa, Trichuris skrjabini and Skrjabinema ovis. All species were searched for in the entire gastrointestinal tract. Six species of nematodes were recovered from abnormal sites, naturally in small numbers of lambs as well as in small amounts: Nematodirus battus in the abomasums (6.67% of lambs), N. filicollis in the caecum and in the colon (%4 and 8%, respectively), T. axei in the colon (9.52%), T. colubriformis in the colon (13.89%), T. vitrinus in the caecum (16.67%), in the colon (20.00%) and in the abomasum (3.33%). T. ovis was found in one case in the small intestine.

Arrested development of sheep strongyles: onset and resumption under field conditions of Central Europe.

Two tracer tests were conducted between August 2004 and March 2007 at an ecological farm in western Bohemia. The first tracer test was performed for the summer-autumn grazing period (onset of arrested development), the second for spring (resumption of arrested development). In the first tracer test, the percentage of nematodes arresting development over the winter months reached 87.7% for Teladorsagia circumcincta, 66.7% for Haemonchus contortus, 89.9% for Nematodirus filicollis, 21.6% for Trichostrongylus axei, and 23.9% for both Trichostrongylus vitrinus and Trichostrongylus colubriformis. None of the arrested larvae were observed with species Cooperia curticei, Nematodirus battus, and Oesophagostomum venulosum. In the second tracer test, a significant increase of adult worms was discovered in March of species T. circumcincta and N. filicollis and Trichostrongylus spp. in February. Redundancy analysis and generalized linear models analyses have confirmed that environmental conditions play a crucial role in hypobiosis of sheep strongyles in the Czech Republic. The analysis of influences of various environmental factors revealed that the number of arrested larvae was negatively influenced by light-day length, sunshine, or daylight decrease (p < 0.01).