RESUMO

Ingested soil may expose free-range animals to environmental pollutants. In pigs, soil ingestion is few described whereas their burrowing behaviour suggests that it could be high. Although highly productive pigs are generally reared indoor, free-range farming is increasing in view of ethical considerations for animal welfare and is a common practice for subsistence agriculture systems. The experiment lasted 8 weeks (2 for adaptation, 6 for measurements) with 24 growing pigs of Guadeloupean Creole (CR) or Large White (LW) breeds. Pigs were assigned to 3 outdoor treatments: high pasture HP (>60 days of regrowth), low pasture LP (35 days of regrowth), and sweet potato SP (sweet potato field). Titanium (soil marker) and chromium (faecal output marker) contents of faeces, vegetation and soil samples were used to estimate individual daily soil ingestions. The average, 10th and 90th percentiles were 440, 200 and 726 g of dry soil per 100 kg body weight, respectively, without significant differences between the 3 outdoor treatments or the 2 breeds but with a significant period (i.e. week of measurements) × treatment interaction (P < 0.001). In the French West Indies, animals may be exposed to chlordecone (CLD), a very persistent organochlorine insecticide. Simulations of CLD tissue contamination due to ingestion of contaminated soil were carried out and compared to the maximum residue limit. These results show that grazing management needs to be adapted to effectively limit soil ingestion by pigs and the impact of a contaminated environment on the sustainability of pig systems.

Assuntos

RESUMO

Free-range livestock are exposed to environmental contaminants by ingesting contaminated matrices mainly soil. Several works evaluated precisely the soil ingestion and its variation factors in ruminants. Contrary to temperate grazing systems, tropical ones were poorly documented whereas weather or traditional grazing practices may change models established in temperate systems. The study was performed in the French West Indies, which are concerned by a widespread environmental chlordecone contamination. The work evaluated daily soil and grass ingestions by tethered growing bulls grazing on a very high sward close to 50 cm for 11 days without being moved. This grazing management is representative to local practices by small farmers or not professional holders and allows completing the results previously obtained. Daily soil ingestion did not significantly increase across time and was on average 26.9 g dry matter/100 kg body weight (i.e. 1.4% of the total mass ingested). Marked individual variations indicated that exposure risk assessments would require experimental designs based on a sufficient number of individuals. This study was also the first to investigate the changes in sward soiling with respect to the distance from the stake and reported lower soil loading on grass in the peripheral than central and intermediate areas.

RESUMO

The consumption of private hold poultry foodstuffs, escaping of official maximum residue limit (MRL) controls in the commercial foodstuff, is an important exposure way for the local populations to chlordecone on the French West Indies. Therefore, chlordecone contamination of different tissues in 42 birds from 32 private holders was determined depending on the contamination of the soil of the outside plot but also surveying the rearing practices of these holders of both islands. Chlordecone contents in tissues increased rapidly with this of the topsoil of the site. The most sensitive tissues to chlordecone presence were egg yolk and liver, followed by abdominal fat and finally leg tissue. The rearing practices varied between the surveyed private holders of both islands. Nevertheless, practices for the distribution of feed and water as well as covering of soil were hardly protective, what would increase the exposure risk of these birds to this potentially present soil-bound contaminant. Although depuration of birds seems possible, the ongoing modelization of the necessary time to meet MRL thresholds indicates that such time lapse seems hardly compatible with acceptable delays for private holders. Therefore, very protective rearing practices are the main way to obtain poultry foodstuffs compliant to MRL, what seems possible if the topsoil is contaminated at less than 0.1 mg kg-1 and perhaps up to 0.5 mg kg-1 if protective practices vis-a-vis of soil exposure are very strict. Nevertheless, a higher contamination of the topsoil seems not compatible with compliant poultry foodstuffs.

Assuntos

RESUMO

Ingested soil is a major vector of organic contaminants from environment to free-ranged animals, particularly for grazing herbivores. Therefore, a better understanding of processes driving soil intake may provide new insights to limit animal exposure to contaminants and ensure safety of animal products. To maintain the supply service of livestock farming activities in contaminated areas, it is necessary to design adapted farming practices aiming at controlling the risk for human health. This study was conducted in the French West Indies, where chlordecone, an organochlorine insecticide previously used to protect banana plantation against the black weevil and banned since 1993, has polluted nearly 20% of agricultural surfaces since the 1970s. A crossover study design was performed to estimate soil intake by twelve tethered Creole young bulls according to different grazing practices. The objectives were to characterize the influence of (i) daily herbage allowance (LOW, HIGH, ADLIB: 100, 150, 300 g DM/kg BW0.75 respectively); (ii) and soil surface moisture (SSM) testing grazing on a water-saturated (HUM) vs dried (DRY) ground. The herbage offer was managed via the allocated surfaces varying the chain length as animal holders commonly do in informal Caribbean systems. The results evidenced an increase in soil intake with DHA reduction (2.1 to 3.8% of DM intake; P < 0.05) and with SSM increase (2.4 to 3.6% of DM intake; P < 0.05). Herbage offer reduction involved a closer-to-the-ground grazing with shorter post-grazing sward surface height (82.2 to 63.3 mm; P < 0.001), and both herbage offer reduction and SSM increase amplified sward soiling (measured from titanium content in unwashed herbage and image analysis). This work showed that soil intake is unavoidable even when herbage offer is very generous. The animals will significantly increase soil intake when herbage offer would be at 150 g DM/kg BW0.75 or less, especially when the grazed surface is humid.

Assuntos

RESUMO

Chlordecone (CLD) is an organochlorine pesticide whose extended use led to the contamination of at least 20% of agricultural soils from the French West Indies. Livestock reared on polluted areas are involuntary contaminated by CLD and their level of contamination may exceed the threshold values set by the European Union. Thus, characterizing the CLD behaviour in farm animals appear as a real issue in terms of food safety for local populations. The aim of this experiment was (i) to characterize the CLD disappearance in various tissues after exposure cessation and (ii) to evaluate the potential effect of body fatness on this process. Two groups of eight growing goats were submitted to either a basal diet or a high energy diet for 50 days before being intravenously contaminated with 1 mg CLD kg(-1) body weight. Two days after CLD contamination, half of the kids of each experimental group were slaughtered in order to determine pollutant levels in the serum, liver, adipose tissues, and empty carcass. The remaining animals were submitted to a 30-day decontamination period before slaughtering and measurements as described above. The implemented nutritional plan resulted in both groups of kids with significant differences in terms of body fatness. CLD was mainly concentrated in the liver of animals as described in the literature. It was found also in kids' empty carcass and adipose tissues; however its levels in the empty carcass (muscles and bones) were unexpected since they were higher than in fat. These results indicate that the lipophilic pollutant CLD is found mainly in liver but also in muscles and fat. Concerning the animals' depuration, a 30-d decontamination period was sufficient to observe a decrease of CLD levels by more than 75% in both experimental groups and neither CLD concentrations nor CLD amounts were significantly affected by kids' body fatness.

Assuntos

RESUMO

The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of soils and subsequently of food chains. In contaminated areas, free-range ducks used to control weeds in orchards may be exposed to CLD through polluted soil ingestion. The question arises whether they may be consumed. Muscovy ducks were raised on a guava orchard planted on a soil moderately contaminated (410 µg CLD/kg dry matter). Ducks were raised indoor up to 6 weeks of age and allowed to range freely outdoors thereafter. Twenty-nine females were sequentially slaughtered by groups of 2 to 5 ducks, after 4, 16, 19, 22 or 26 weeks spent in the orchard or after 16-17 weeks in the orchard followed by 3, 6 or 9 weeks in a closed shelter for depuration. CLD concentration increased from 258 to 1051, 96 to 278, 60 to 169 and 48 to 145 µg/kg fresh matter (FM) as the exposure through grazing increased from 4 to 22 weeks, in liver, abdominal fat and leg with and without skin, respectively. Eggs collected in the orchard contained up to 1001 µg CLD/kg FM. All these values exceeded the Maximum Residue Limit (MRL) of 20 µg/kg FM. CLD concentration in all tissues was divided by around 10 within the 9-week confinement period. Despite this quite rapid decontamination, it is estimated that 12-13 weeks would be required to achieve the MRL in liver and in eggs, and 5-6 weeks in leg muscle. Such durations would be too long in practice. Thus, the consumption of products from free-range ducks should be avoided, even in areas mildly contaminated with CLD.

Assuntos