Trends in the quantity of foreign substances in feed mixtures and in pigsty dust at large pig farms

In the period from January 1983 to December 1985 we examined thirty-five samples of commercial feed mixtures for pigs and thirty samples of pigsty dust deposition from large pig-houses in a region with extensive mining (lignite extraction) situated in the Hodonín district. In comparison with the contents of contaminants in the feed mixtures over the period from January 1983 (1/83) to June 1984 (6/84), the zinc and lindane concentrations increased to 213.3% (P less than 0.01) and 133.3%, respectively, from July 1984 (7/84) to December 1985 (12/85). The concentrations of copper, manganese, lead, cadmium, mercury (P less than 0.05), DDT (P less than 0.01) and aflatoxin B1 in the feed mixtures decreased. The highest permissible amount of contaminants in the feed mixtures was exceeded in the 1/83-6/84 period in cadmium (limit value 0.3 mg per kg) and mercury (limit value 0.1 mg per kg), in the 7/84-12/85 period only in zinc (limit value 250 mg per kg). In comparison with the values of contaminants in pigsty dust deposition recorded from January 1983 to June 1984, the lead concentration increased to 555.5% in the 7/84-12/85 period, lindane concentration rose to 569.0% (P less than 0.01), zinc concentration to 220.5% (P less than 0.01), the copper, manganese, cadmium, mercury concentrations (P less than 0.05) decreased, and the concentrations of DDT, aflatoxin B1 and polychlorinated biphenyls also dropped. It is desirable to evaluate in regular intervals the spectrum of contaminants both in feed mixtures and in pigsty dust deposition and to monitor other potential sources of contaminants in the pig-houses.     

Physical, chemical and biological study of dust from large-scale pig farms

Dust deposition in 16 halls of two large pig-fattening farms with dry or wet feeding systems was analyzed. In the halls with wet feeding the samples contained maximally 28 dust particles up to 10 micron and 17 particles up to 5 micron per cm3 of air, in the halls with dry feeding 220 particles smaller than 10 micron and 205 particles smaller than 5 micron per cm3 of air. The total amino acid content in the dust deposition was 17.440 +/- 1.820 g per 100 g of sample and the content of nitrogen compounds (N X X 6.25, %), was 24.170 +/- 2.910. The contents of chemical elements were as follows (mg per kg): zinc 448 +/- 151; manganese 109.9 +/- 49.5; copper 40.5 +/- 12.1; lead 4.77 +/- +/- 4.79; chromium 1.64 +/- 1.47; cadmium 1.61 +/- 1.62; mercury 0.36 +/- 0.39. Chlorinated carbohydrates and triazine and diazine herbicides were present in the following amounts (mg per kg): HCB 0.0023 +/- 0.0021; Lindane 0.0058 +/- 0.0079; DDE 0.0048 +/- +/- 0.0024; DDT 0.0065 +/- 0.0015; Simazine 0.060 +/- 0.020; Atrazine 0.083 +/- 0.059; Prometryn 0.093 +/- 0.040; Chloridazon 0.036 +/- 0.008; Terbutryn 0.085 +/- 0.029. The content of aflatoxin B1 was 12.89 +/- 9.31 micrograms per kg and the maximum amount of polychlorinated biphenyls was 8 mg per kg. Nitrovin was found out only in the dust of two halls: 4.0 and 7.9 mg per kg. The dust deposition also contained 21 genera and species of moulds, six species of mites, numerous saprophytic bacteria and, in some cases, Staphylococcus aureus. For the time being, no viruses have been detected in the dust samples.     

饲料镉对必需微量元素在猪组织中分布的影响

将96头体重27kg左右杜长大生长猪,随机分为2组,每组设3个重复(公、母各半),分别饲喂添加0、10.0mg/kg镉的饲粮,进行了83d的饲养试验,期间每隔两周固定从每个重复中选2头猪(公、母各半)前腔静脉采血。饲养试验结束后,从每组中各选取12头试验猪(公母各半)屠宰,并采集血清、内脏器官样品测定铁、铜、锌的含量。结果表明:添加10.0mg/kg镉显著影响猪的生长性能,其日增重降低18.6%(P<0.05),饲料转化率降低15.1%(P<0.05);10.0mg/kg镉引起了一些组织中铁含量的显著降低(P<0.05)及铜含量的显著升高(P<0.05),肾锌水平显著提高(P<0.05),而心脏、胰脏中锌含量显著降低(P<0.05);添加镉对淋巴结和心脏铁含量、淋巴结和胰脏铜含量及肝脏和脾脏锌含量无显著(P>0.05)影响。     

Monitoring chromosome mutations in large-scale breeding operations

The frequency of chromosomal aberrations and exchanges of sister chromatids (SCEs) in peripheral lymphocytes was studied in 65 pigs from five large breeding herds. Four groups comprised fattened pigs and the fifth group consisted of sows from a large multiplier breeding herd. During the investigation, the dust from the sites was analyzed for the presence of zinc, lead, cadmium, mercury, aflatoxin B1, PCB, DDT, and lindane. The average frequency of aberrant cells (AB.B) in the pigs of group I was 3.85 +/- 1.60%, in group II 2.10 +/- 1.52%, in group III 5.01 +/- 2.1%, in group IV 3.50 +/- 1.58%, and in group V 6.20 +/- 3.21%. The cytogenetic finding corresponded to the differences in the amount of foreign substances found in the dust on the premises where the animals of all groups were kept. The average frequency of the SCEs was 7.00 +/- 1.10 (I), 6.51 +/- 0.89 (II), 6.92 +/- 0.72 (III), 7.10 +/- 0.85 (IV) and 7.06 +/- 1.47 (V) per one cell. Statistically significant differences in the numbers of AB.B. were recorded between groups II and I, II and IV, I and III, IV and V (p less than 0.05) and between groups II and III, II and V (p less than 0.01). There was no statistically significant difference in the frequency of SCEs. The determination of the frequency of chromosomal aberrations can be used for the hygienic control of the degree of exposure of pigs to mutagens.     

Chlortetracycline in swine-bioavailability and pharmacokinetics in fasted and fed pigs

Chlortetracycline hydrochloride was administered intra-arterially (11 mg/kg) and as an oral drench (33 mg/kg) to ten 21.0-31.5-kg pigs. Five of the pigs were fasted 18 h prior to dosing and five of the pigs were fed ad libitum prior to dosing. The mean volume of distribution determined by area-under-the-curve calculations for the fasted pigs (0.967 +/- 0.210 l/kg) was significantly less (P less than 0.05) than the mean volume of distribution for the fed pigs (1.39 +/- 0.31 l/kg). Mean total body clearance of the drug was also significantly less (P less than 0.05) in the fasted pigs (0.165 +/- 0.055 l/kg/h) as compared to the fed pigs (0.307 +/- 0.053 l/kg/h). The elimination constants (beta) were not found to be statistically different (P less than 0.05): 0.1811 +/- 0.0057 for the fasted pigs; 0.2260 +/- 0.0461 for the fed pigs. The bioavailability for both groups was similar; 19.12 +/- 8.3% for the fasted pigs and 17.88 +/- 5.3% for the fed pigs. In a second experiment three groups of six pigs which weighed 34.5-44.1 kg were fed a corn-soy diet ad libitum. The rations were fortified with chlortetracycline at 100, 400 or 1000 mg chlortetracycline hydrochloride/kg feed. Chlortetracycline concentrations were determined in plasma samples collected over a 6-day period. Plasma chlortetracycline concentrations reach a plateau within 24 h after initial access to the trial diets and were highly correlated with the dose of the drug consumed (r2 = 0.97).     

Complement activity, serum protein, and hepatic changes in guinea pigs given sterigmatocystin or aflatoxin, alone or in combination

Effects of either sterigmatocystin or aflatoxin, alone or in combination, given orally to guinea pigs were studied. Sterigmatocystin and aflatoxin B1 given alone and in combination at 4.2 mg/day and 0.01 mg/day, respectively, markedly reduced body weight. Although changes in total serum protein were not marked in any of the guinea pigs in this study, sterigmatocystin given alone and aflatoxin given alone significantly ( less than 0.05) decreased alpha2-globulin. The combination of toxins significantly (P less than 0.01) increased albumin and significantly (P less than 0.01) decreased both alpha2- and beta-globulins. Sterigmatocystin depressed complement activity, although not significantly. However, the combination of sterimatocystin with 0.01 mg of aflatoxin B1/day (an amount that does not affect complement activity alone) significantly (P less than 0.01) reduced complement activity. Increased severity of lesions was not found in guinea pigs given aflatoxin at 0.01 mg of B1 equivalents/day in addition to the sterigmatocystin.     

Suppression of cell-mediated immunity by purified aflatoxin B1 in broiler chicks

The effect of purified aflatoxin B1 on cell-mediated immunity (CMI) in broiler chicks was assessed using doses of 0.3 and 1 mg/kg feed from hatching to 6 weeks of age. Total lymphocyte and T lymphocyte counts and the 2,4-dinitrofluorobenzene skin sensitivity test, graft-versus-host reaction and nitroblue tetrazolium salt reduction tests were used to evaluate CMI. Both doses of aflatoxin B1, including the apparently nontoxic dose of 0.3 mg/kg feed, caused a significant (P less than 0.05) decline in CMI. The functional activity of splenic macrophages was decreased significantly (P less than 0.05) by both doses of the toxin.     

Level of heavy metals in the liver of sheep in experimental poisoning with copper oxide from industrial emissions

The life span and cumulation of heavy metals in the liver of 12 ewes of the Improved Wallachian breed were investigated in relation to feeding pollutants from a copper works. The total intake of copper, iron, zinc, arsenic, cadmium and lead was 466.8; 1253.93; 111.67; 34.75; 0.091; 2.13 mg per experimental animal/day, respectively. The average life span of ewes in the experimental group was 77 days. The difference between the first and the last animal which died from copper intoxication was 18 days. The concentration of copper in the liver of sheep who died from intoxication by this metal (2138.28 +/- 1090.96 mg. kg-1 in dry matter) was significantly higher (p less than 0.01) if compared with the control ewes (212.9 +/- 58.33 mg. .kg-1 in dry matter). In the course of observations no direct dependence between the concentration of copper in the liver and the life span of experimental animals was confirmed. The content of iron and zinc in the liver of experimental animals was within the reference range; the difference in zinc was statistically significant when compared with the control group (p less than 0.01). The intake of pollutants from the copper works increased significantly the concentration of arsenic and lead in the liver of experimental animals (p less than 0.01) if compared with the control group. The amount of cadmium in the liver of experimental ewes was 0.304 +/- 0.22 mg. .kg-1 and in the control ewes 0.285 +/- 0.10 mg.kg-1 in dry matter; no significant difference was determined at the same time.     

Performance of finishing pigs in hoop structures and confinement during winter and summer

Performance of finishing pigs in hoop structures or confinement during winter and summer was evaluated in Iowa. Hoops are large, tent-like shelters with cornstalks or straw for bedding. During summer and winter seasons for 3 yr (1998 to 2001), six trials were conducted using three hoop barns (designed for 150 pigs per pen, one pen per hoop) or a mechanically ventilated confinement barn with slatted floors (designed for 22 pigs per pen, six pens in the barn). A total of 3,518 pigs started the trials. Summer trials were June through October, and winter trials were December through April. Target stocking density was 1.11 m2/pig in hoops and 0.74 m2/pig in confinement. Identical corn-based diets were fed ad libitum from 16 to 118 kg for 127 d. Pigs were scanned before harvest for backfat and loin muscle area. When seasons were merged (season x housing interaction, P > or = 0.05), hoop-fed pigs had more backfat (21.8 +/- 0.3 vs 20.8 +/- 0.2 mm; P < 0.001), smaller loin muscle area (41.3 +/- 0.3 vs 43.0 +/- 0.2 cm2; P < 0.001), less lean percentage (51.1 +/- 0.2 vs 52.1 +/- 0.1%; P < 0.001), and less yield (74.9 vs 75.8 +/- 0.1%; P < 0.001) than confinement-fed pigs. When season x housing type interactions were observed (P < 0.004), summer hoop-fed pigs had greater ADG (834 +/- 5 vs 802 +/- 3 g/d; P < 0.001), required fewer days to 113 kg (174.9 +/- 0.9 vs 178.5 +/- 0.6 d; P < 0.01), had similar ADFI (2.40 +/- 0.03 vs 2.35 +/- 0.02 kg/d, as-fed basis) and gain:feed (G:F; 348 +/- 4 vs 342 +/- 3 g/kg) compared with confinement-fed pigs. Lean gain/day and efficiency of lean gain did not differ between housing systems. During winter, hoop-fed pigs had similar ADG (794 +/- 5 vs 801 +/- 3 g/ d), required more days to 113 kg (176.7 +/- 0.9 vs 172.9 +/- 0.6 d; P < 0.01), had greater ADFI (2.54 +/- 0.03 vs 2.35 +/- 0.02; P < 0.001), less G:F (313 +/- 4 vs 341 +/- 3; P < 0.001), less lean gain/day (312 +/- 2 vs 322 +/- 1 g/d; P < 0.01), and less efficiency of lean gain (130 +/- 2 vs 144 +/- 1 g lean gain/kg feed; P < 0.01) than confinement-fed pigs. Percentage of mortalities and culls did not differ between housing systems. During summer, there was a trend for fewer light pigs at marketing (< 100 kg) from hoops (0.8 vs 1.7%; P = 0.10). During winter, there were more light pigs at marketing from hoops (3.9 vs 1.3%; P = 0.01) than from confinement. Bedding use in hoops was 92 and 122 kg/pig for summer and winter, respectively. Performance of finishing pigs in bedded hoop structures depends in part on thermal environment.     

云南湿热地区距瓣豆的铜、锌和锰营养

在云南省亚热带湿热地区为了探讨微量元素铜、锌和锰施用对引进优良豆科牧草距瓣豆生长的影响,开展铜、锌和锰的不同施量对距瓣豆干物质产量、种子产量影响的单因子完全随机区组试验.结果表明,施用铜1.2～2.4 kg/hm2和锰3. kg,/hm2的处理比对照距瓣豆干物质产量分别提高58.4%～88.4%和48.1%(P<0.05),种子产量分别提高295.5%～272.7%和80.4%(P<0.01);施铜还可提高距瓣豆氮、钙、硫、铜、锌和锰含量,显著增加单位面积距瓣豆对氮的需求量(P<0.01),其次是磷、钾、钙、硫、铜、镁、锌和锰的营养需求量(P＜0.05);施适量锰可增加距瓣豆的钙、锌和锰含量,显著增加单位面积距瓣豆的钙和锌产量(P＜0.01),其次是氮、磷、钾、镁、铜和锰的产量(P＜0.05).施用锌虽然对距瓣豆干物质产量和种子产量提高没有显著效果,但是可以提高距瓣豆的钙、锌和锰含量,显著提高单位面积距瓣豆的锌产量(P＜0.01),其次是氮、钾和锰的产量(P＞0.05),显著的降低距瓣豆对钙(P<0.01)和磷(P<0.05)的吸收量.综合分析,在施磷肥和其他元素肥的基础上,加施铜1.2 kg/hm2或锰3.9 kg/hm2,可获得高产、收益好的距瓣豆优质饲草,同时满足饲养牲畜生产的营养需要.     

Short- and long-term influence of perinatal dexamethasone treatment on swine growth

The objective was to evaluate the effects of perinatal dexamethasone (Dex) treatment on postnatal growth in pigs. Experiment 1: 42 piglets were assigned according to birth weight and sex to receive either Dex (1 mg/kg body weight) or sterile saline (Control; equivalent volume) i.m. within 1h of birth. Body weights were recorded weekly and at sacrifice (day 18). Birth weights (1.43 +/- 0.05 kg) did not differ between treatment groups (P > 0.19). At day 18, Dex pigs were heavier than Control pigs (5.46 +/- 0.24 and 4.45 +/- 0.26 kg, respectively). Serum IGF-1 was 17.3% higher in Dex pigs (P < 0.04) compared to Controls. For serum GH, there was a treatment x sex interaction (P < 0.04) with GH being 51% lower in Dex males compared to Control males, and no differences in females. Experiment 2: 71 pigs were assigned according to birth weight and sex to receive either Dex (2 mg/kg body weight) or sterile saline (Control; equivalent volume) i.m. within 1 h of birth. Body weights were recorded weekly until weaning (day 21) and then every 14th day until market weight. Birth weights (1.53 +/- 0.03 kg) did not differ (P > 0.35) between treatment groups or sexes. Dexamethasone increased growth from birth to market weight by 4.15%. Carcass weights were not different (P > 0.34) between Dex (89.9 +/- 1.17 kg) and Control pigs (88.6 +/- 1.36 kg). Overall, Dex enhanced growth in pigs from birth to market weight with minimal effects on carcass and meat quality.     

Ecotoxicologic relations on a large pig-fattening farm located in a lignite mining area and near and solid-fuel electical power plant]

Major contaminants identified in 1983-1984 on a pig fattening farm with an output of 60,000 pigs per annum, located in a lignite mining area and near a solid fuel power plant, were mercury, cadmium, lead, chromium and aflatoxin B1 (Tab. I, II, III, IV). Feed samples were collected from througs to assess the contamination load at feed uptake. Permissible concentrations of mercury, chromium, cadmium, aflatoxin B1, lead and atrazin in the feed were exceeded in 56, 50, 31, 19, 6 and 6% samples, respectively (Tab. I). Stable dust deposits, in which the contaminants concentrate, (Tab. I) proved to be a suitable material for assessing the type and level of environmental contamination. Permissible concentrations of mercury, cadmium and lead in porcine muscles were exceeded in 65, 51 and 24% samples, respectively (Tab. III). Corresponding values of mercury, cadmium, lead and aflatoxin B1 in the liver were 27, 27, 16 and 3%, respectively (Tab. III) and those of mercury, lead and chromium in kidneys 24, 22 and 5%, respectively (Tab. III). Rather surprisingly, elevated pancreatic concentrations of aflatoxin B1 were found (Tab. IV). Pigs fattened in the contaminated environment (i.e. fed contaminated feed mixtures, inspiring contaminated dust and absorbing percutaneously contaminants form dust deposits on the body surface) showed: 1) Impairment of the genetic apparatus (percentage of aberrant peripheral leucocytes elevated to 6.2%); 2) a certain degree of immunosuppression (concentrations of IgG, IgM and IgA reduced by 16.9, 45.1 and 45.0%, respectively); 3) higher feed consumption per 1 kg weight gain (4 kg) and lower average daily weight gain (0.57 kg); 4) increased incidence of health disorders (dermatitis in 25%, pancreatopathy in 13%, liver dystrophy in 8% and femoral fracture in 6% of the pigs). Unfortunately, the authors were not allowed to analyse ash and solid emissions from the power plant. Therefore the share of the emissions in the overall environmental contamination on the fattening farm could not be quantified. The personnel, working in the contaminated environment for a prolonged period, is endangered most of all by stable dust, being exposed to its mechanical, chemical, allergic and infectious effects (Tab. I). In addition to the chemical contaminants, 21 mould genera and species, six mite species and numerous saprophytic and some pathogenic bacteria were demonstrated in stable dust samples in our earlier experiments. Consumption of meat and organs from pigs fattened in a contaminated environment is associated with the risk of an increased uptake of various contaminants.(ABSTRACT TRUNCATED AT 400 WORDS)     

Experimental combined aflatoxin B1 and ochratoxin A intoxication in pigs

Twenty-one pigs weighing approximately 18 kg were placed in 7 groups of 3 and given diets containing respectively aflatoxin B1 alone at 0.375 and 0.0750 mg/kg, ochratoxin A alone at 1 and 2 mg/kg, 0.375 mg/kg of aflatoxin B1 plus 1 mg/kg of ochratoxin A and 0.750 mg/kg aflatoxin B1 and 2 mg/kg of ochratoxin A. The remaining group served as untreated control. At the respective dose levels, pigs receiving similar doses of ochratoxin A alone or in combination with aflatoxin B1, were similarly affected, the clinical effects of aflatoxin having been mostly obscured by those due to ochratoxin A. Mild degenerative hepatic changes typical of aflatoxicosis were observed in pigs fed this toxin alone or in combination with ochratoxin A. In kidneys of pigs fed diet containing 1 and 2 mg of ochratoxin A alone changes included interstitial fibrosis of the vortex and dystrophy and degeneration of the tubular epithelium. Similar lesions but less pronounced fibrosis were found in kidneys of pigs receiving both toxins. The respective lower dose levels of mycotoxins selected were judged to be about the no-effect levels for each dosed separately under the conditions of the trial. Such levels have been found not infrequently on mould affected grain and stock foods. The result highlights the difficulties that may be experienced in the recognition of such multimycotoxicoses as they are likely to occur in the field and indicate the need for toxicological analysis as well as pathological investigation in establishing a diagnosis.     

Distribution of harmful metals in sheep after experimental administration of industrial emissions]

Cu, Fe, Zn, Mo, Se, As, Cd and Pb distribution was followed in the organisms of seven lambing ewes after these animals had been on a diet with industrial contaminants generated by the copper and zinc works. The amount of ingested contaminants per lambing ewe was 31.99 g a day pursuant to the starting liveweight. Per-head daily intake of Cu, Fe, Zn, Mo, Se, As, Cd and Pb in mg: 402.02; 95.97; 6158.07; 1.436; 2.975; 15.38; 0.597; 22.14. The first ewe with symptoms of zinc intoxication died on day 42 and the last on day 58. The highest Zn concentrations were recorded in the dry matter of dead ewe liver (1167.3 +/- 314.1 mg per kg). An amount of 1048 +/- 283.7 mg Zn per kg was cumulated in the kidneys in the process of contaminant administration. High Zn contents were also observed in the uterus and spleen. The highest amounts of Cu were cumulated in liver (445.6 238.1 mg per kg). Spleen was an organ with the highest concentrations of Fe, the ovaries cumulated the highest amounts of Mo and bony tissue and ovaries the highest amounts of Se. An exposure of the organisms to As, Cd and Pb in ewes intoxicated with zinc from a source of industrial pollutants, was reflected in their high contents in the ovaries, kidneys, liver and bony tissue. These results demonstrate that in sheep the liver, kidneys, uterus, spleen and ovaries are the most suitable organs if it is to prove zinc intoxication caused by pollutants from the copper and zinc works. Liver, kidneys, ovaries, uterus, spleen, skeletal muscles and bony tissue seem to be suitable for an evaluation of Cu, Fe, Mo, Se, As, Cd and Pb distribution in the organisms of ewes which died from zinc intoxication caused by pollutants from the above-mentioned source.     

The concentrations of copper, zinc, manganese and selenium in the hair of newborn piglets and their dams.

Instrumental neutron activation analysis was employed to determine the levels of certain trace elements in the hair of newborn piglets and their dams. The mean concentrations (mumoles/mg) of copper, zinc, manganese and selenium in the neonatal piglet hair samples were 222 +/- 55, 4940 +/- 1728, 12.7 +/- 17.1 and 8.9 +/- 5.5, respectively, and in sow hair samples the mean concentrations (mumoles/mg) were 156 +/- 22, 5124 +/- 1927, 31.7 +/- 22.2 and 6.5 +/- 3.7, respectively. The mean copper level was higher (p less than 0.05) in piglet hair compared with sow hair. However the mean concentration of manganese was lower (p less than 0.05) in piglet hair. There was no relationship between the trace mineral levels found in the piglets' hair and the dams' hair. The levels of copper, zinc, manganese and selenium found in piglet hair were shown to be unrelated to the piglet body weight. The feasibility of using porcine hair as a practical biopsy material for trace element analysis is discussed.     

Effects of grouping unfamiliar cohorts, high ambient temperature and stocking density on live performance of growing pigs

Ninety-six crossbred intact male pigs (34.5 +/- 3.5 kg BW) were allocated by weight and vocalization score to a 2 x 2 x 2 dynamic experimental design including two stocking densities (1 or 2 m(2)/pig), two temperatures (22 degrees C and 30 degrees C), and two short groupings of unfamiliar cohorts (six pigs as one pig per group, and six pigs per group). The study was conducted over 8 wk, and live weight gain (WTG) and feed intake (FI; as-fed basis) were measured weekly. During the first week, pigs were housed in individual pens from four independent rooms. To group pigs, pen partitions were removed. Pigs were grouped in Rooms 2 and 3 from wk 2 to 4, and in Rooms 1 and 4 during wk 7. Temperature was increased from 22 degrees C to 30 degrees C in Rooms 1 and 2 during wk 4 and 7. Pen partitions were replaced in Rooms 2 and 3 at the end of wk 4 and in Rooms 1 and 4 at the end of wk 7 to return pigs to their individual pens. Grouping pigs decreased FI during wk 3 (15.08 +/- 0.43 vs. 14.03 +/- 0.41 kg P < 0.10), and during wk 7 (17.42 +/- 0.46 vs. 14.24 +/- 0.41 kg; P < 0.01). In addition, grouping had a negative effect (P < 0.001) on WTG at wk 3 (7.38 +/- 0.28 vs. 5.71 +/- 0.28 kg) and at wk 7 (6.70 +/- 0.26 vs. 2.99 +/- 0.26 kg). For grouped pigs, raising the temperature decreased (P < 0.01) WTG (7.49 +/- 0.29 vs. 6.41 +/- 0.29 kg during wk 4, and 3.37 +/- 0.38 vs. 2.62 +/- 0.38 kg during wk 7). Mean FI was decreased (P < 0.01) with the 30 degrees C treatment during wk 7 only (15.49 +/- 0.33 kg at 22 degrees C compared with 12.99 +/- 0.33 kg at 30 degrees C). Compensatory feed intake was evident after the treatments had ceased at wk 6, whereby previously heat-treated grouped pigs had a higher FI (17.97 +/- 0.45 kg) than the animals individually housed at 22 degrees C (12.99 +/- 0.33 kg). Stocking density effects were noted after the grouping and high temperature treatments had ceased. For instance, during wk 5, low-density-housed pigs grew faster (P < 0.001) than their high-density counterparts (9.04 +/- 0.38 vs. 7.49 +/- 0.29 kg). In conclusion, under the conditions of this study, the grouping of unfamiliar cohorts and high ambient temperature treatments had a detrimental effect on pig performance, and these effects were reversible.     

Biological, chemical and pathohistologic study of the skin in papular dermatitis in fattened pigs

We examined the skin samples from 23 fattened pigs with papular dermatitis (PD) and from 17 pigs showing no skin lesions; the live weight of the pigs was from 95 to 105 kg and the pigs came from a large fattening house D that is located in the region where the mines are frequent (lignite extraction). It was only in 26% of pigs with PD where the common ectoparasites Haematopinus suis and Sarcoptes scabiei var. suis were found out. The skin lesions were not fluorescent in the light of Wood's lamp. The fungi Aspergillus flavus, A. fumigatus, A. tereus, Chrysosporium, Mucor sp., Scopulariopsis sp. were sporadically isolated from the skin lesions in 39% of pigs with PD. In 65% of pigs with PD Staphylococcus aureus was isolated from the skin lesions, which was not found in pigs without dermal lesions. Staphylococcus epidermidis was isolated in 87% of pigs with PD and 58% of pigs without any skin changes. The skin lesions were virus-free. Increased concentrations of cadmium and mercury were observed in the skin of pigs with PD and in control pigs. The concentration of aflatoxin B1 in the skin of the two groups of pigs did not exceed the level of 5 micrograms X kg-1, in PD pigs it was, however, twice higher than in the clinically healthy pigs. The residues of chlorinated hydrocarbons in the subcutaneous fat were not higher than the certified hygienic levels. Both epidermis and corium are affected by inflammatory lesions. At the beginning, neutrophil infiltration with necrotization of epithelial cells prevails. It is followed by capillary proliferation with angioblast and fibroblast multiplication and straggled lymphoid infiltration. It is necessary to distinguish by differential diagnostics: swine pox, parakeratosis of swine, lesions of impetigo contagiosa suum, pustular dermatitis and scab of swine, and from rarely occurring skin diseases of swine hypotrichosis cystica suis and demodicosis of swine. No conclusions can be drawn explicitly on the etiology and pathogenesis of papular dermatitis in fattened pigs. We must study the potential interactions of negative environmental factors with regulating homeostatic and adaptation mechanisms in fattened pigs.     

Effect of D-glucose on in vitro short-circuit current in neonatal calf jejunum and rabbit ileum

Thin sheets of mucosa from small intestine of neonatal calves were mounted in incubation chambers for in vitro studies. These mucosal sheets generated a potential difference (PD) of 2.05 +/- 0.02 mV (mean +/- SEM), short-circuit current (SCC) of 23.32 +/- 3.81 microA x cm2, and tissue resistance of 86.22 +/- 4.41 ohms x cm2 (n = 6). Ouabain in the serosal bathing solution caused a sharp decrease in the SCC (P less than 0.01) and PD (P less than 0.005), a decrease in tissue K content (P less than 0.05), and an increase in tissue Na content (P less than 0.05). The mucosa responded to D-glucose by an increase in PD (P less than 0.001) and SCC (P less than 0.001). In vitro methods used in the calf were validated in similar experiments on rabbit ileum.     

Effects of cadmium on serum sex hormone levels in pigs

An inhibition of sex hormone secretion is observed in domestic animals exposed to cadmium in experimental conditions. Ninety-six gilts (Duroc x Landrace x Yorkshire, initial weight 27.59 kg) were randomly assigned into four different groups with three replications in each group (eight gilts per replication). The groups received the corn-soybean basal diet and supplemented with 0, 0.5, 5.0 and 10.0 mg/kg cadmium (as CdCl2) respectively. The feeding trial was ended when body weight of pigs was approximately 90 kg. The results showed that 10.0 mg/kg cadmium significantly decreased average daily gain (p < 0.05) and increased feed/gain ratio (p < 0.05) of pigs. Follicle-stimulating hormone, luteinizing hormone, oestradiol (E2) and progesterone levels in serum of the pigs fed the diet supplemented with 10.0 mg/kg cadmium were lower significantly than those of the control (p < 0.05). Compared with the control, no changes were found in the levels mentioned above when the pigs fed the diet supplemented with 0.5 or 5.0 mg/kg cadmium (p > 0.05). The changes of regulatory mechanism of the pituitary-ovary axis may be the result of cadmium accumulation in pituitary and ovary and should be investigated further.     

A balanced anesthesia with a combination of xylazine, ketamine and butorphanol and its antagonism by yohimbine in pigs.

The effects of intramuscular injections of xylazine (2 mg/kg)-ketamine (15 mg/kg) [X-K15], and xylazine (2 mg/kg)-ketamine (5 mg/kg)-butorphanol (0.22 mg/kg) [X-K5-B] were compared in atropinized (0.05 mg/kg) miniature pigs (pigs). Both combinations induced the anesthesia for more than 1 hr, however X-K5-B induced the more potent and well balanced anesthesia as compared with X-K15, although the amount of ketamine was reduced to one third. The duration of loss of pedal reflex, an indicator of surgical anesthesia, in X-K5-B (62 +/- 13 min) was significantly (P less than 0.05) longer than in X-K15 (28 +/- 19 min). In addition, X-K5-B was accompanied by loss of laryngeal reflex in all pigs. Recovery from anesthesia in X-K5-B was much smoother than in X-K15, and the administration of yohimbine (0.05 mg/kg) could rapidly and smoothly reverse the anesthesia induced by X-K5-B, although it was accompanied by a transient fall in blood pressure and tachycardia. The combination of xylazine, ketamine and butorphanol appears to be a relatively safe and widely available anesthesia for the period of one hour in pigs.