Toxicological evaluation of an unextracted Aurantiochytrium limacinum biomass, a novel docosahexaenoic acid rich feed ingredient.

The purpose of this paper was to evaluate the toxicological potential of a heterotrophically grown unextracted Aurantiochytrium limacinum biomass (AURA) when used as a food additive. The following toxicological assessments were conducted on this novel docosahexaenoic acid rich feed ingredient: Mutagenic activity was tested by means of the Ames' test using five Salmonella typhimurium strains; clastogenic activity was investigated using the micronucleus test in male and female Sprague Dawley rats; genotoxic activity was assessed by means of the in vitro metaphase analysis tests in human lymphocytes; oral toxicity was tested by administration of AURA at various concentrations; eye and skin irritation was assessed in rabbits according to OECD guidelines; skin sensitivity was established in guinea pigs by means of the Buehler test. All conducted tests were considered valid under the experimental conditions. No significant mutagenic activity or clastogenic activity was observed. Genotoxic activity in human lymphocytes was not induced. Oral administration of 276 mg AURA/kg bw1 and 2000 mg AURA/kg bw resulted in no mortality or signs of acute toxicity. Daily administration of 1000 mg AURA/kg bw caused no mortality or biologically relevant signs of toxicity and was established as the No Observable Adverse Effect Level. AURA was also found to be a non-irritant for the eye and skin of the rabbit and was non-sensitizing to guinea pig skin.

Heterotrophic Aurantiochytrium sp. supplementation to layer diets sustainably increases the omega-3 concentration of eggs.

1. The consumption of adequate amounts of the long-chain polyunsaturated omega-3 fatty acids (n-3 LC-PUFA) has been associated with beneficial effects on human health. Eggs are commonly consumed worldwide, and their omega-3 content can be easily altered by changing the diets of laying hens and so represent an important target for enrichment. 2. In this study, the effect of supplementing laying hens with DHA-rich, Aurantiochytrium limacinum at three different inclusion levels was investigated over a 24-week period. 3. Significant increases in egg DHA concentrations were observed after four weeks and were maintained for the duration of the 24-week study. The supplemented eggs in the current study had a DHA content of 82, 101, and 129 mg/yolk when supplemented with 0.25%, 0.5% and 1% treatments, respectively, which meets the EU criteria to be considered 'high in omega-3'. 4. Using the sustainably grown protist Aurantiochytrium limacinum to supplement layer diets increased the egg DHA concentration and decreased the n-6/n-3 ratio, improving the nutritional value of the eggs for human consumers.

Redressing the balance: including DHA-rich Aurantiochytrium limacinum in broiler diets increases tissue omega-3 fatty acid content and lowers the n-6:n-3 ratio.

1. The consumption of sufficient quantities of long chain omega-3 fatty acids (n-3 LCPUFA) from meat and other animal products can lead to a variety of health benefits in humans. The fatty acid content of poultry meat can be increased by feeding birds ingredients that are rich in n-3 LCFUFA 2. The effect of feeding a docosahexaenoic acid (DHA) rich Aurantiochytrium limacinum biomass (AURA) on the fatty acid content of breast and thigh tissues was investigated in a feeding trial with 2880 male Ross 308 broilers. The broiler diets were supplemented with either 0, 0.25, 0.5 or 1% AURA from day 21 to 42 of age. 3. Supplementation significantly increased the DHA content of both breast and thigh meat at an inclusion rate of 1% in the diet, leading to a total of 42 and 46 mg DHA/100 g of fresh breast or thigh tissue respectively. Significant increases in the tissue eicosapentaenoic acid (EPA) concentration were seen alongside a reduced omega-6/omega-3 ratio, improving the nutritional value of the meat for consumers and identifying supplementation of broiler diets with A. limacinum as an effective and sustainable method to increase n-3 LCPUFA consumption in the human population.

Effects of a DHA-rich unextracted microalgae as a dietary supplement on performance, carcass traits and meat fatty acid profile in growing-finishing pigs.

Two 125-day experiments of the same design were conducted to evaluate the effects of a heterotrophically grown microalgae (AURA) containing docosahexaenoic acid (DHA) on pig performance, carcass traits and the fatty acid composition of lean and adipose tissue. In each experiment, 144 Hypor pigs were blocked by sex, allocated to three treatment groups, and fed 0, 0.25% or 0.50% AURA in isonutritive, isocaloric diets. Pigs were weighed on days 0, 28, 56, 84 and 112. Feed and water intakes were measured every 28 days. Pigs were slaughtered on day 125. Data from the two studies were analysed as a single data set. Performance and carcass traits did not differ between treatments. Both microalgae treatment levels enriched (p < .05) Longissimus lumborum (LL) and backfat in DHA and improved (p < .05) their ratios of n-6 to n-3 fatty acids.

The effect of dietary supplementation with Aurantiochytrium limacinum on lactating dairy cows in terms of animal health, productivity and milk composition.

The aim of this study was to investigate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA), on a variety of health and productivity parameters in lactating cows. Twenty-four cows were blocked by parity and number of days in milk and then randomly assigned to a control (CON; n = 12) group with no algal supplementation, or a treatment group (AURA; n = 12) provided with 100 g AURA cow-1  day-1 or 16 g DHA cow-1  day-1 . A variety of health and productivity measurements were taken, and results indicated that supplementation had no negative effects on animal health in terms of somatic cell count, haematological and biochemical blood parameters, while body condition was marginally improved by algal supplementation. No differences were found for the various production parameters measured; however, a tendency towards increased milk production was observed for the AURA group during the final stage of the study (+4.5 kg cow-1  day-1 , day 78-84). The fatty acid profile of milk was improved by supplementation, with significantly lower saturated fatty acids, significantly higher omega-3 fatty acids and an improved omega-3/omega-6 ratio observed when compared to the control group. The amount of DHA in the milk of cows provided 105 g AURA head-1  day-1 was 4.7 mg/100 g milk with a peak transfer efficiency from feed to milk at day 49 of 8.3%. These results indicate that supplementation with 105 g AURA head-1  day-1 resulted in the successful enrichment of milk with DHA without negatively impacting the health or productivity of the animals.

Freedom from Echinococcus multilocularis: an Irish perspective.

Echinococcus multilocularis, an emerging zoonotic disease is extending its geographical distribution within the European Union (EU). At present, five member states including Ireland are considered free. Previous EU regulations on importing domestic pets allowed these countries to maintain national rules that required all dogs be treated with an anti-cestode compound before entry. The controls on the movement of pet animals within the EU were recently reviewed by the European Commission and it was decided that the five countries had to demonstrate freedom from E. multilocularis before they could continue with the mandatory tapeworm treatment. The intestines of 220, 307 and 216 foxes were examined, using the sedimentation and counting technique, for the presence of E. multilocularis in 2003, 2009 and 2010 respectively. There was no evidence of the parasite in the foxes. These data together with the negative results from 130 foxes examined by other workers during 1999 and 2000 (Wolfe et al., 2001) were used to estimate the probability of freedom using scenario trees. The result of the model suggested that the probability that Ireland was free from E. multilocularis in 2010 was high, 0.98 (95% confidence interval, 0.94-1.00), thus justifying the retention of the mandatory tapeworm treatment for dogs entering the country from other EU member states.

The prevalence and distribution of Alaria alata, a potential zoonotic parasite, in foxes in Ireland.

The digenean trematode Alaria alata, an intestinal parasite of wild canids is widely distributed in Europe. The recent finding of the mesocercarial life cycle stage in the paratenic wild boar host suggests that it may potentially infect humans Mohl et al. (Parasitol Res 105:1-15, 2009). Over 500 foxes were examined during a wildlife survey for zoonotic diseases in 2009 and 2010. The prevalence of A. alata ranged from 21% to 26% in 2009 and 2010, and the intensity of infection varied, with the majority of foxes having between one and ten trematodes, but a small number of animals had parasitic burdens greater than 500. The location of foxes was geo-referenced and mapped using a geographic information system. The results of the spatial analysis suggest that A. alata may have a limited distribution being confined mainly to areas of pasture especially in the central plain and north Munster. Hot spot analysis indicated a clustering and that the level of parasitism was greatest in foxes from those areas where the prevalence of infection was highest.

Dietary calcium content, calcium balance and mode of uptake in a subterranean mammal, the Damara mole-rat.

Calcium flux and mode of uptake were investigated in an underground dwelling mole-rat, Cryptomys damarensis, fed diets of varying Ca content. The amount of dietary Ca positively influenced the amounts ingested, absorbed and retained. The linear relationship between ingested and absorbed Ca was significantly (P less than 0.001) correlated, implying that this process is nonsaturable. When mole-rats were fed a diet low in Ca, apparent fractional absorption of Ca was high (85.88%). This increased still further when the diet was changed to a food of greater Ca content (96.13%, carrots; 96.97%, gemsbok cucumber). Mineral homeostasis is regulated at the intestinal level in most mammals. Regardless of dietary Ca content, uptake of 45Ca (examined via the everted gut sac technique) was passive, confirming that absorption is via a nonsaturable process. Plasma Ca concentrations were not tightly regulated, yet when fed the diet with the highest Ca content, mole-rats were not hypercalcemic. Regardless of diets, Ca apparent fractional retention was positive, and approached physiological maxima (greater than 97%). Cryptomys damarensis, in using highly efficient modes of mineral uptake and retention, is therefore capable of fully exploiting the limited food resources of their arid ecotope.