Tissue deposition of polychlorinated biphenyls in cats fed Atlantic Ocean bluefish.

Bluefish (Pomatomus saltatrix), a very popular marine sport fish caught in Atlantic coastal waters, contain significant levels of polychlorinated biphenyls (PCBs). Since fish can be an appreciable portion of human and feline diets, a feeding study was conducted with cats fed exclusively bluefish for 86 days with determination of tissue concentrations of PCBs. The concentrations of PCBs in brain, liver, and fat were significantly higher (p = 0.01) in the fish-fed cats than in the control group using the Wilcoxon rank sum test. The highest PCB levels were in fat, the median concentrations being 48 and 0.61 ppm (dry weight) in the fish-fed and control cats, respectively. The significance of the results is discussed.     

Experimental polychlorinated biphenyl toxicosis in germfree pigs.

The effects of polychlorinated biphenyls were studied in eight germfree pigs. Beginning at fourteen days of age, two pigs each were fed daily 12.5, 25, 50 and 100 mg/kg body weight of polychlorinated biphenyls as Aroclor 1254. Three germfree pigs were negative controls. Clinically the treated pigs had inappetance, a hemorrhagic diarrhea, erythema of the nose and the anus, retarded growth, distended abdomen and at the higher dose levels, incoordination and coma followed by death. Deaths occurred in 11 to 35 days after exposure. At necropsy, the piglets exhibited grossly enlarged mottled liver, erosions of the gastric mucosa, hemorrhages through the mesentery and the intestinal wall, a fibrinous pericarditis, a hypoplastic thymus and congested swollen thyroid glands. The histopathological lesions included hepatic centrolobular necrosis, interstitial myocarditis, endocarditis, myopathy of the muscles, gastric erosions and colitis. All of the organs examined for polychlorinated biphenyls had elevated residue levels which were particularly high in the fat, liver, psoas muscle, brain and kidney and were higher than has been reported in conventional pigs fed approximately equal concentrations of polychlorinated biphenyls. The severity of clinical signs, pathological changes and tissue concentrations were directly related to the dose administered and were more pronounced in the germfree pigs than has been described in conventional pigs.     

Nutrient utilization by sheep fed forage grown on soil treated with fluidized-bed combustion residue.

A mineral balance trial was conducted with 18 wether lambs fed sun-cured hay harvested from pastures located on a reclaimed strip-mined site. The following soil applications were made during each of 3 yr: 1) none, 2) dolomitic limestone and 3) fluidized-bed combustion residue (FBCR). Because FBCR had half the buffering capacity of limestone, it was applied at twice the rate of limestone. Apparent digestibility of hemicellulose was higher (P less than .05) for limestone-amended forage than for FBCR-amended forage (70.2 vs 67.0%), and apparent digestibility of cellulose was higher (P less than .05) for amended forages (66.7%) than for the control (63.9%). Apparent absorption and retention of N were similar among treatments, when expressed as a percentage of intake. Lambs fed control forage were in negative Ca balance, lower (P less than .01) than with amended forages. Apparent absorption and retention of Mg and Fe (g/d basis) were higher (P less than .05) for lambs on the limestone treatment than for lambs on the FBCR treatment. Apparent absorption of S was higher (P less than .01) for lambs on the FBCR treatment than for those on the limestone treatment. These differences were related to differences in mineral concentrations of the forages. Serum P was lower (P less than .05) for lambs fed FBCR-treated forage than for lambs fed limestone-treated forage (10.1 vs 12.9 mg/dl). Soil amendment with FBCR did not have deleterious effects on digestibility or mineral metabolism; in fact, it may have enhanced utilization of Ca and S and improved digestibility of some fiber components by lambs.     

苜蓿施用污泥效果的研究Ⅰ对苜蓿生长及元素含量的影响

将兰州市七里河污水处理厂生活污泥施用于人工种植的新疆大叶苜蓿草地，探讨了不同施用量对苜蓿生长及各元素含量的影响。研究结果表明，施用1.0-2.0kg/m^2污泥，苜蓿地上生物量显著增加，第一年增产23％－31％，第二年增产15％－31％。施用污泥苜蓿地上和地下部组织中N，P，Ca,Mg和Mn的含量总体呈增加趋势，Fe含量显著增加，而K和重金属元素Ni、Pb、As和Hg的含量与对照无显著差异，Zn和Cu的积累增多，但地上部组织中重金属元素均未超过植物中的平均含量，施用污泥未对新疆大叶苜蓿造成重金属污染。     

Toxicological effects of gamma-irradiated sewage solids fed as seven percent of diet to sheep for four years

Breeding ewes in drylot were fed pelleted complete diets with 3% cottonseed meal (CSM) or 7% dried, gamma-irradiated sewage solids (DGSS) for 4 yr. Cytochrome P-450 (P-450) content and enzyme activities for xenobiotics biotransformations were assayed in livers after 2 yr and in livers, kidneys and ileal tissue after 4 yr. Dietary DGSS caused no increase in P-450 and few changes in activities of oxidative, hydrolative and conjugative biotransformational enzymes. Consumption of DGSS for 4 yr caused slight enlargement of spleens (1.1-fold, P less than .10) and ovaries (1.3-fold, P less than .10), but no change in size of livers, kidneys, hearts, adrenals and thyroids (P greater than .10), nor liver vitamin A levels (P greater than .10). Of 22 refractory lipophilic residues assayed in abdominal adipose tissue, few were detected and of those detected DGSS caused none to exceed normal levels. Dietary DGSS increased (P less than .01) Fe in livers 1.5-fold and in spleens 5.6-fold, and increased Cu in livers 1.3-fold (P less than .01) and in kidneys 1.2-fold (P less than .05). Dietary DGSS increased Cd levels in livers (P less than .01) but not in kidneys or spleens (P greater than .10); yet all Cd levels were within ranges for livestock fed conventional feed. Dietary DGSS caused no increase (P greater than .10) in levels of Ag, Ca, Cr, Hg, K, Mg, Mn, Na, Ni, P, Pb or Zn in livers, kidneys or spleens. There were no histopathological lesions of toxicosis except mild hemosiderosis of spleens. Consumption of a diet with 7% DGSS throughout 4 yr caused no hazardous accumulation of toxic elements and little, if any, evidence of toxicosis.     

Very low helminth infection in sheep grazed on pastures fertilised by sewage sludge or cattle slurry

Helminth infection acquired by lambs grazing on pastures fertilised either by urban sewage sludge or cattle slurry were studied in temperate Central Western France. The aim was to assess the risk of larval cestodoses in lambs after sewage application and of digestive tract nematode infection following the slurry application. Twenty-six sheep were allocated on two paddocks of 0.7 ha, one fertilised with sludge and the other with cattle slurry. The delay between application and actual grazing was 6 weeks; grazing on these paddocks extended from mid July to beginning of November 2002. The herbage biomass was slightly increased in the sludge paddock but it did not result in an increase of lamb live weight, compared with the slurry paddock. The lambs did not acquire cysticercosis or any other larval cestodoses in the sewage sludge group and only very limited infections with Cooperia spp. and Nematodirus spp. were observed in the slurry group. It was concluded that in our conditions the helminth risk was extremely low and was not a cause of restriction of the use of these biowastes.     

Metabolism and excretion of ochratoxin A fed to sheep.

Hydrolysis of the mycotoxin ochratoxin A (OA) to ochratoxin alpha (Oalpha) by microorganisms within the gastrointestinal tract leads to the excretion of OA as the nontoxic alpha form. The Oalpha form is the principal means for the detoxification of OA. In the current experiment, three groups of four sheep were fed diets consisting of 70% concentrates and 30% hay (dry matter basis, energy to supply 1.1 times the requirement for maintenance) for 4 wk with three dietary concentrations of OA (0, 2, or 5 mg/kg of concentrate feed). The OA content did not affect feed intake or nutrient digestibility. In a preliminary experiment, an OA dose of 20 mg/kg of concentrate feed greatly reduced feed intake. After 1, 2, 3, and 4 wk of the trial, significant concentrations of OA were detected in the serum of the animals fed 2 or 5 mg of OA/kg feed. This suggested that even at a dosage of 2 mg of OA/kg of concentrate feed, considerable amounts of OA were not degraded by ruminal and intestinal microorganisms. The analysis of the feces and urine samples reflected these findings; OA and Oalpha were found in significant concentrations, escaping fermentation in the rumen and in the hindgut. The current experiment demonstrates that OA hydrolysis in the gastrointestinal tract of sheep is substantially less than previously described, especially if OA is ingested in combination with concentrate-rich diets.     

Toxicologic studies with sheep fed colored magazines and newsprint.

Paper containing colored inks from magazines and newspapers was fed as 23% of their ration to sheep for 175 days. A similar ration containing oat hulls in place of the paper was fed to control animals. The paper-fed animals consumed 29% more feed than the controls but the feed efficiency (kg animal weight gained/kg ration consumed) of the two rations was approximately equivalent. Lead contained in the paper accumulated in animal tissues. Hepatic microsomal mixed function oxidase activity was several fold higher in the paper-fed animals than the controls. Histopathologic examination of liver and kidney using light and electron microscopy revealed no lesions attributable to diet.     

Toxicologic studies with lambs fed sugar beets grown on municipal sludge-amended soil: lowered relative hemoglobin in red blood cells and mutagens in blood and excreta

Sugar beets grown on municipal sludge-amended soil were fed to growing lambs for 66 days. The relative hemoglobin content was significantly lower (P less than 0.05) in the lambs fed the sludge-grown sugar beets. The concentration of direct-acting mutagens was significantly higher (P less than 0.05) than controls in blood and urine of the lambs fed the sludge-grown beets. Cadmium concentration was higher, but not significantly (P greater than 0.05) in the livers and kidneys of the lambs fed the sludge-grown beets as compared with controls. Significant differences between treatment groups were not observed in active or passive K+ influxes in RBC; in the activity of hepatic microsomal aniline hydroxylase in p-nitroanisole-O-demethylase, aminopyrene-N-demethylase, or arylhydrocarbon hydroxylase; in tissue ultrastructure of kidney, liver, or muscle as examined by electron microscopy; or in carcass weight, dressing percentage, quality, or yield grade.     

Chronic oral exposure of rainbow trout (Salmo gairdneri) to a polychlorinated biphenyl (Aroclor 1254): pathological effects.

Groups of eight rainbow trout (Salmo gairdneri) were fed rations containing 0 ppm, 1 ppm, 10 ppm and 100 ppm of the polychlorinated biphenyl, Aroclor 1254, over a period of up to 330 days. Growth rates were unaffected by these levels. Pathological changes were found in the kidneys of 13 fish on the polychlorinated biphenyl ration. Foci of nephrosis with cellular or granular cast formation were seen. The greatest number of cases occured in fish at the 10 ppm concentration. An increase in the number of hepatocytes per unit area was related to the greater concentration of polychlorinated biphenyls in the diet. A reduction in the amount of white pulp in the spleen was observed in 23 of 27 fish on the 10 ppm and 100 ppm diets. The fish with nephrosis had reduced splenic white pulp and lowered white cell counts. Fish fed the 1 ppm and 10 ppm levels had mean tissue residues of 1.4 and 2.3 ppm polychlorinated biphenyl respectively. Fish on the 100 ppm ration had a mean value of 80.1 ppm polychlorinated biphenyl content.     

Comparative investigation of salinomycin and flavophospholipol in sheep fed different composed diets.

The effects of salinomycin and flavophospholipol, and their relationship with the diet, were studied in nine ruminally and duodenally cannulated wethers. Within the composition of the ration, the levels of rumen degradable protein (RDP) and non-structural carbohydrates (NSC) were changed (diet H: 74% RDP and 38% NSC; diet M: 57% RDP and 32% NSC; diet L: 48% RDP and 23% NSC). There was no clear treatment effect of flavophospholipol on propionate concentration. Salinomycin supplementation appeared to be more effective than flavophospholipol in the increase of propionate concentration at the expense of acetic acid. Salinomycin significantly reduced the ammonia concentration of the rumen fluid. Microbial N content of the duodenal digesta was significantly lower when salinomycin was used. Salinomycin inhibited proteolysis and reduced the efficiency of microbial protein synthesis. The effect of salinomycin on ruminal N metabolism was independent of the composition of substrate. Unlike salinomycin, flavophospholipol tended to increase proteolysis in the rumen and did not inhibit protein synthesis. The effect of salinomycin on ruminal fermentation and the duodenal flow of nutrients were independent of substrate composition.     

苜蓿施用污泥效果的研究Ⅱ对土壤理化性质及元素含量的影响

将兰州市七里河污水处理厂生活污泥施用于苜蓿人工草地，探讨其对土壤环境的影响，结果表明，施用污泥，改善了土壤理化性质，增加了土壤肥力，土壤中有机质，全N和全P的含量增加，土壤容重下降，污泥施用量与土壤有机质，全氮含量呈极显著正相关（P＜0．01），与土壤容得呈极显著负相关（P＜0．01），当污泥施用量在4kg/m^2以上时，0－20cm土层Fe和Ca的含量显著增加，施用量8kg/m^2时，Cu和Zn的含量显著高于对照，而K，Mn和重金属元素Ni,Pb,As,Hg的含量与对照无显著差异，且各元素都未向土壤下层迁移，没有对土壤环境造成污染。     

Macromineral absorption in sheep fed tetany-prone and non-tetany-prone hays

Two experiments were conducted to determine some of the factors that led to hypomagnesemic tetany associated with the feeding of two orchardgrass hays. Sixteen mature Columbia and Suffolk wethers (62 to 72 kg), four of which were fitted with ruminal and abomasal cannulae, were fed one of two tetany-prone orchardgrass hays or a non-tetany-prone bromegrass hay. In Exp. 1, 12 wethers were used in a completely random design metabolism experiment to measure apparent absorption and retention of macrominerals. In Exp. 2, four wethers with ruminal and abomasal cannulae were used in a completely random design experiment to monitor pre-intestinal mineral absorption and ruminal characteristics. This experiment was replicated once, with wethers remaining on their diets for 16 d in each replication. In the metabolism experiment, apparent absorption and retention of Mg as a percentage of intake were lower (P less than .01 and P less than .05) for one tetany-prone orchardgrass hay compared with the other orchardgrass hay. Pre-intestinal absorption of Mg in the cannulated wethers was greater (P less than .01) for the orchardgrass hays than for the bromegrass hay. Pre-intestinal Mg absorption was higher (P less than .01), both in terms of grams per day and a percentage of intake for the orchardgrass hay with the highest Mg content. In the noncannulated wethers, the percentage of water-soluble Mg in the feces was lower (P less than .01) for the tetany-prone hays, indicating that a decrease in Mg solubility in the intestine may have influenced Mg apparent absorption.(ABSTRACT TRUNCATED AT 250 WORDS)