Factors affecting excretory behavior of pigs.

A 2(4) factorial experiment with six pens per treatment was conducted to examine the factors affecting the excretory behavior of growing-finishing pigs. The factors investigated were partition type (open or closed), pig density (9 or 14 pigs/pen, size: 2 m x 4.5 m), position of nipple drinker in the pen (back wall of the pen or side in front of slatted area), and prior experience of pigs (training or no training). A total of 1,104 pigs at a weight interval of 28.4 +/- .2 to 91.4 +/- .4 kg were used in this study. Pen cleanliness was assessed by a dung scoring system, and growth rate was determined over the growing-finishing period. Partition type, nipple drinker position, or prior training of pigs had no effect on growth rate. Stocking pigs at 14 pigs/pen reduced growth rate (P < .05) compared with 9 pigs/pen (.80 vs .83 kg/d). Significant differences for pen dirtiness were found for partition type. Pens with closed partitions were cleaner than those with open partitions (P = .0001) and pens became significantly dirtier as pigs grew older or heavier (P < .01). There was a significant interaction effect between pen partition and pig density as well as an interaction among pen partition, pig density, and water position (P < .05).

Effect of exposure to operant-controlled microwaves on certain blood and immunological parameters in the young chick.

Twenty-two 1-wk-old broiler chicks (Gallus domesticus) were housed at 16 C and operantly conditioned to activate either a 250-W infrared bulb (control) or a microwave generator delivering 13 mW/cm2 (treated). Plasma corticosterone concentration did not differ between groups (P greater than .05) at 4 wk of age. At that time the birds were killed, and post-mortem examination revealed no treatment differences in gross morphology of the chicks or in weights of spleen and bursa of Fabricius (P greater than .05). Histological study of comparable segments of spleen, bursa, adrenal, and thyroid tissue did not show differences in any of the chosen parameters (P greater than .05). Heterophil:lymphocyte ratios, packed cell volume, and total plasma protein content were similar between groups (P greater than .05). These results suggest that operant exposure to low density microwave radiation did not result in stress or immunological disturbances.

Performance of male broiler chicks exposed to heat from infrared or microwave sources.

In eight trials, 240 male broiler birds, initially 7 days old, were randomly allocated to three treatments. Treatments were: continuous infrared (CI), intermittent infrared (II; 4 min on, 2 min off, 10 cycles/h), and intermittent microwaves (IM; 2 min on, 4 min off, 10 cycles/h). At the conclusion of the 14-day experimental period the 21-day-old birds were killed. Although there were significant differences (P less than or equal to .05) in mean gain over the 2-wk treatment period between trials, no differences (P greater than .05) were attributed to treatments. There were, however, significant differences in feed:gain ratios between trials and between treatments. Feed:gain ratios of birds kept under CI and II treatments did not differ significantly (P greater than .05). However, feed:gain ratios, 1.61 +/- .04 and 1.57 +/- .04 for CI and II, respectively, differed significantly (P less than or equal to .05) from that of the IM treatment (1.76 +/- .04). The protein content of chicks under II was significantly (P less than or equal to .05) lower than that of birds under IM. There were no differences (P greater than .05) in fat, ash, calcium, and phosphorus content of chicks among treatments.

Performance of large groups of chicks using operant conditioning to control the thermal environment.

In four trials, 408, 320, 160, and 400 chicks were housed on litter in pens 1.8 x 2.4 m. Eight pens were used for each trial. For the first 6 days the environmental temperature was maintained at 28 C; on Day 7 the temperature was reduced to 16 C. Four pens were equipped with microswitches; the remaining four pens were each heated by two infrared lamps in constant operation. When chicks struck the microswitch, infrared lamps were turned on for 1 min during the learning phase when chicks were being conditioned to the experimental setup and 4 min during the experimental phase during which data were collected for analysis. Feed intake, gain, and mortality were recorded. Trials 1 and 2 were concluded at 28 days and Trials 3 and 4 concluded at 21 days. At the conclusion of the trials protein, fat, and water content of the birds were determined. Additional analysis for ash content was performed for Trials 1 and 2 only. No significant differences (P greater than .05) in gain, feed conversion, body composition, and mortality rate were found between treatments. Chicks provided with continuous heat were exposed to three times as much supplemental heat as operant conditioned groups yet feed efficiency was unaffected.

Effect of air movement on operant heat demand of chicks.

Chicks, 8 days of age, were housed in a wind tunnel at temperatures from 12 to 28 C in increments of 4 C. The tunnel was equipped with a microswitch, an infrared bulb located above the switch, and a small electric fan controlled by a rheostat. Following learning, chicks were exposed at each temperature to air speeds of 0, .5, 1.0, and 1.5 m/s according to a Latin-square design. Chicks readily responded to air speed and temperature changes. For each increase of .1 m/s the effective environmental temperature dropped .6 C.

Behavioral observations and operant procedures using microwaves as a heat source for young chicks.

Four trials, using operant conditioning procedures, were conducted to study the response of chicks, housed at 16 C, to microwave or infrared heat. Microwave power density was 26 mW/cm2 in Trial 1, 13 mW/cm2 in Trial 2, and 10 mW/cm2 in Trials 3 and 4. Chicks voluntarily demanded between 28 and 63% as much heat (min heat/hr) from microwave source as from infrared source at all power densities. There was no correlation, however, between the ratio of heat demanded and the power density used. There were no significant differences in growth between infrared- or microwave-heated chicks. It is evident from these studies that 8-day-old broiler chicks are capable of associating the performance of a task with a thermal reward provided by the microwaves. They are also able to utilize these microwaves through operant conditioning without any visible detrimental effect to their health or behavior.

Evaluation of chemically induced cytogenetic lesions in rabbit oocytes. III. A postimplantation analysis of streptonigrin effects.

The frequency of consistent structural chromosome aberrations was determined for 108 fetuses (day 14 of gestation) from 20 female rabbits treated before conception with 90 micrograms/kg of streptonigrin (NSC-45383). The findings by karyotype analysis of 1.85% of the fetuses with consistent aberrations was compared with 6.32% frequency previously observed in 6-day (preimplantation) blastocysts from identically treated females and found to be significantly reduced. The interpretation of the findings is that the developmental events of implantation and placentation are effective in eliminating from further gestation the majority of the rabbit conceptuses with consistent structural chromosome abnormalities. The data are also discussed relative to the predictive nature of somatic cell chromosome damage in women of childbearing age being an estimator of risk of producing offspring with structural chromosome aberrations. The data show that preconceptional treatment of female rabbits with streptonigrin caused a shift in the cytogenetically determined sex ratio of the 14-day fetuses, but not of the 6-day blastocysts. The significant decrease in relative numbers of males observed is consistent with the induction of lethal mutations on the X chromosome. This finding is discussed in conjunction with the timing and parental specificity of X chromosome inactivation during mammalian embryonic development.

Observations of environmental thermoregulation by chicks.

Chicks, 8 days of age, were housed at 20 C in a 48 x 45 cm chamber with a microswitch in one wall. Pressing the microswitch provided radiant heat from an infrared bulb located above the switch. Six experiments were conducted using from two to eight chicks per group. Heat was provided for 2 or 3 min. In two experiments chicks were on litter; in four experiments chicks were on wire floors. Chicks provided themselves with heat without difficulty and reduced heat demand when housed on litter rather than wire. Less total heat was provided with reward times of 2 min. No diurnal rhythm was evident.

Effects of defeathering and insulative jackets on production by laying hens at low temperatures.

Exposure to a temperature of 5 degrees C compared with 20 degrees C resulted in a 20.5% increase in food consumption and an 18.8% decrease in efficiency of food utilisation with intermediate values resulting from exposure to 10 degrees C and 15 degrees C. Removal of feathers from the neck, back and (or) breast resulted in a 5 to 6% increase in food consumption. The effects of feather removal and temperature on food consumption were additive. Cloth jackets effectively insulated the back and breast areas when feathers had been removed but also resulted in increased food intake and lower efficiency.

Effects of feather cover and insulative jackets on metabolic rate of laying hens.

Two experiments were conducted to determine the influence of feather cover and newly-devised insulative jackets on the heat production in Single Comb White Leghorn laying hens at 20 C. An open-circuit calorimeter was used to measure the gaseous exchange of the birds. With ad libitum feeding, birds with clipped back and breast feathers produced 6% more heat than did normally feathered hens. This difference was removed by placing jackets on the defeathered birds. The jackets also decreased the surface temperature of the feather-clipped areas, indicating an effective insulation. When the jackets were applied to naturally poor-feathered hens, fasting heat production decreased significantly, but not to the base level of that of normally feathered hens.

Cytogenetic effects of cis-platinum(II)diamminedichloride in vivo.

The chemotherapeutic agent cis-platinum(II)diamminedichloride (cis-PDD) has been shown to be mutagenic, teratogenic, and carcinogenic. We determined the cytogenetic effects of cis-PDD on human and rabbit lymphocytes in vitro and on rabbit marrow cells, lymph node cells, and lymphocytes in vivo. Lymphocyte cultures from two humans and one rabbit were treated in vitro with cis-PDD. For in vivo studies, five New Zealand white rabbits were given iv injections of cis-PDD. Posttreatment blood samples were withdrawn for analysis and rabbits were sacrificed at either 6 or 24 hr for cytogenetic analysis of marrow and node cells. Sister chromatid exchange (SCE) analysis of human and rabbit metaphases from lymphocytes treated in vitro showed that rabbit lymphocytes are more sensitive to SCE induction by cis-PDD. Significant increases in SCE were observed in lymphocyte cultures obtained as early as 1 hr post treatment from injected rabbits. Analysis of node, marrow, and lymphocyte metaphases from injected rabbits showed a high number of chromosome aberrations in these cells with bone marrow showing a delayed response to treatment. These results indicate that cis-PDD is clastogenic in hematopoietic tissues in vivo and that SCE methodology may be useful in monitoring patients receiving cis-PDD therapy.

Efficacy of salinomycin and stenorol against various species of Eimeria and effect on chick performance.

Three experiments were designed to test the efficacy of salinomycin and stenorol against infection by various Eimeria species on cage reared broiler type chicks. Efficacy was based on a coccidial index. Sixty parts per million salinomycin alone or in combination with 50 ppm 3 nitro significantly improved the index over basal treatments or when 3 nitro was used alone. The differences in index values recorded for coban and salinomycin were not significant. Stenorol significantly improved the index and appeared to be a most effective anticoccidial product. Broiler chickens reared in floor pens to 8 weeks showed a significant reduction in weight gain when the diet contained salinomycin +3 nitro or coban. Stenorol at 3, 6, or 9 ppm reduced body weight, with linear regression for this effect being highly significant (P less than .01). No coccidiosis was observed.

Frequency of F116-mediated transduction of Pseudomonas aeruginosa in a freshwater environment.

Transduction of Pseudomonas aeruginosa streptomycin resistance by a generalized transducing phage, F116, was shown to occur during a 10-day incubation in a flow-through environmental test chamber suspended in a freshwater reservoir. Mean F116 transduction frequencies ranged from 1.4 X 10(-5) to 8.3 X 10(-2) transductants per recipient during the in situ incubation. These transduction frequencies were comparable to transduction frequencies determined in preliminary laboratory transduction experiments. The results demonstrate the potential for naturally occurring transduction in aquatic environments and concurrent environmental and ecological ramifications.

Dietary energy and fat content as factors in the nutrition of developing egg strain pullets and young hens. 3. Effects on hepatic lipogenic enzyme activity and body chemical composition during the first 20 weeks of lay.

One hundred and twenty six commercial White Leghorn pullets were housed in cages at 23 weeks of age and fed two laying diets that in energy and fat content. Changes in hepatic "citrate-cleavage" and "malic" enzyme activity and changes in liver and body chemical composition were measured each week during the first 20 weeks of lay. Average daily caloric intake was greater for the birds fed the high energy laying diets even though these birds consumed 11% less feed. While energy content of the laying diet failed (P = 0.05) to affect body weight gains, liver weight, liver fat content and hepatic enzyme activity, significant (P = 0.05) increases in abdominal fat pad weight and total body fat content were noted. The findings of significant alterations in total carcass composition in birds receiving the high energy laying diet support the conclusion that energy content of the layer diet will influence the carcass composition of modern day egg producing strains.

Dietary energy and fat content as factors in the nutrition of developing egg strain pullets and young hens. 4. Effect on growth, hepatic lipogenic enzyme activity and body chemical composition of White Leghorn pullets from hatch to 20 weeks of age.

Nine starting and rearing diets (three energy levels each with three fat levels) were fed to commercial White Leghorn chicks from hatch to 20 weeks of age. As noted in the earlier papers of this series, pullets fed the high energy rearing diets showed significant (P = 0.05) reductions in feed intake, however, average daily caloric intake was greater (P = 0.05) for pullets consuming the low energy rearing diets. Fat content of the diet had not influence on either daily feed (g.) or caloric (kcal.) intake. Energy content of the diets failed (P = 0.05) to affect parameters related to body growth and development, hepatic citrate-cleavage and "malic" enzyme activity and liver or body composition. Fat content of the diet depressed hepatic enzyme activity while no effect was noted on body weight, liver weight or body composition. The onset of sexual maturity altered lipid metabolism in the developing pullets. Significant (P = 0.05) energy level by fat level interactions were noted in only two of the 20 parameters studied in this experiment. In vitro assay of hepatic citrate-cleavage and "malic" enzyme activity proved to be of little value in predicting hepatic lipogenic activity and subsequent effects on liver and total body composition.

The effects of elevated levels of sodium chloride on ascites and related problems in turkeys.

The response of young poults to diets containing 0.7, 1.2, 1.7 and 2.7 per cent sodium chloride was studied. Water intake, feed intake and wieght gain were not significantly influenced by treatment. Only the highest level caused a significant increase in mortality. Ascites was not a consistent finding even on high levels of salt. A straight line best described the response but confidence limits were large and this was also true for heart, kidney and lung lesions. Lesions showing myocardial distension with pericardial adhesions, severe congestion of the lungs and enlarged pale kidneys seemed more indicative of salt intoxication than classic ascites. Microscopically heterophilic (eosinophilic) lung and meningeal infiltrates accompanied by myocardial degeneration and adhesions were suggestive, but not specific, of salt intoxication.