Poult performance as influenced by age of dam, genetic line, and dietary vitamin E.

An experiment was conducted to measure the effects of age of dam, genetic line, and dietary levels of vitamin E on growth and immunocompetence of poults. Age of dam was defined as younger (in early egg production) and older (past peak production); line consisted of a commercial sire and dam line; and dietary vitamin E was supplemented into the diet at 10 and 300 IU/kg of feed. Traits measured included body, liver, gizzard, and yolk sac weights at hatch; BW and feed conversion to 9, 28, and 42 d; response to SRBC, Phaseolus vulgaris agglutinin-P, and Escherichia coli administered at 28 d of age; and response to a cold stress on d 5 posthatch. Differences among genetic lines were evident with growth greater for poults from the sire than from the dam line. Performance of poults from older dams was generally superior to that of poults from younger dams. The higher level of vitamin E resulted in a greater than 7-fold increase in blood plasma vitamin E and reduced mortality. There were interactions among the main effects in which the fitness of poults from younger dams was enhanced by the higher level of vitamin E and the effect of breeder age differed among genetic lines.

Absence of a protective effect of corticosterone on 0-0-diisopropyl phosphorofluoridate (DFP) induced delayed neurotoxicity in chickens.

Chickens given 15 to 45 ppm dietary corticosterone 1 day prior to and 5 days following subcutaneous administration of 1 mg/kg 0,0-diisopropyl phosphorofluoridate (DFP) were not protected from either clinical delayed neuropathy, depression of neurotoxic esterase activity or advanced degenerative peripheral nerve myelinated fiber damage.

Effect of supplemental corticosterone and social stress on organophosphorus-induced delayed neuropathy in chickens.

Adult White Leghorn roosters maintained for 3 months in an environment of low social stress (LSS) were given triorthotolyl phosphate (TOTP), 180 mg/kg po, 24 h after initial exposure to either an environment of high social stress (HSS) or exogenously administered corticosterone (200 ppm in diet). The environment of HSS or the administration of corticosterone were continued for 10 days after TOTP administration. It was noted that the heterophil/lymphocyte ratio, a hematological indicator of stress, was similar in both groups and both had similar scores for clinical signs of delayed neuropathy. Both heterophil/lymphocyte ratios and clinical scores were significantly lower in chickens kept in the LSS environment and not fed corticosterone than in chickens kept in the HSS environment or fed corticosterone.

The effect of stress on the response of chickens to coccidiosis vaccination.

Six-week-old Leghorn chickens, which had been adapted to both their environment and cage mates, were orally inoculated with 400 Eimeria tenella oocysts as a means of low-dose vaccination. At 2, 3, 4, 5 or 6 days after vaccine administration, the birds were subject to 24 h of social stress through a prescribed method of random redistribution. Two weeks after vaccine administration, the birds were challenged by oral inoculation with 8000 oocysts. Caecal lesion scores were determined 6 days after challenge. Vaccinated chickens were more resistant to lesion formation than unvaccinated controls, and protection, as determined by lower lesion scores, was significantly enhanced when stress in the form of social disruption was applied on the fourth day following vaccine administration.

Relationship between body-weight gain after movement of chickens to an unfamiliar cage and response to Escherichia coli challenge infection.

One day after chickens were moved from a brooder to unfamiliar cages, there was a high negative correlation (p < 0.001) between an individual's body-weight gain and the severity of response to Escherichia coli challenge infection.

Effect of ascorbic acid on the mortality of Leghorn-type chickens due to overheating.

Leghorn-type chickens in a relatively low-stress environment were fed diets containing 0 to 1100 mg of ascorbic acid (AA)/kg for 1 day before they were subjected to overheating. As the dose of AA increased from 0 to 330 mg/kg, there was decreasing mortality from 40% to 0%. As the dose of AA was increased further, there was an increase in mortality.

Effect of ascorbic acid on antibody response of stressed and unstressed chickens.

Chickens were given feed containing a series of doses of ascorbic acid between 0 and 880 mg/kg starting 1 day before and continuing for 5 days after sheep erythrocytes were administered intravenously. Antibody titers were reduced when doses were greater than 220 mg/kg. Cold stress resulted in a reduction of titers, which was partly alleviated by doses between 220 and 440 mg/kg. Results were similar when 25 mg of corticosterone was added to the feed to simulate stress. Titers of treated stressed chickens were never greater than those of the untreated unstressed controls.

Effect of environmental stress on the responses of ascorbic-acid-treated chickens to Escherichia coli challenge infection.

As the stressfulness of the environment increased (measured as increasing heterophil/lymphocyte [H/L] ratios), resistance of chickens to Escherichia coli challenge infection increased. At a relatively low level of environmental stress (H/L ratio = 0.33), the incidence of severe lesions was 22% in chickens fed diets containing 330 mg of ascorbic acid (AA)/kg and 80% in undosed controls. As the level of environmental stress increased, the dose of AA required for maximum reduction of the incidence of severe lesions increased, and the difference in lesion incidence between AA-dosed and undosed chickens decreased. When environmental stress resulted in H/L ratios of 0.53 or more, AA did not ameliorate the severity of infection. At levels of stress characterized by H/L ratios between 0.39 and 0.44, increasing doses of AA resulted in increased susceptibility to E. coli until a dose associated with maximum susceptibility was reached. Further increases in the dose of AA resulted in decreased susceptibility until a dose associated with maximum resistance was reached. In chickens fed feed containing 15 mg corticosterone/kg, increasing doses of AA resulted in increasing susceptibility to E. coli.

Factors affecting the development of respiratory disease complex in chickens.

Factors playing a part in the development of respiratory disease complex in chickens were investigated in a series of experiments. The experimental infection was produced by exposing chickens to Mycoplasma gallisepticum and the B1 vaccine strain of Newcastle disease virus and later exposing them to aerosols containing the O1:K1 serotype of Escherichia coli. Chickens became susceptible (pericarditis or death) to E. coli 8 days after mixed respiratory disease challenge. One day after respiratory disease challenge, lesions consisted of edema and infiltration with lymphoid cells and heterophils. At the time of susceptibility to E. coli, the lesions were strongly lymphoid with many dense follicular areas and very few heterophils. The incidence of pericarditis and death was similar when the concentration of bacteria in the aerosol inoculum ranged between 10(9)/ml and 10(5)/ml. At the time of maximum susceptibility to aerosol challenge, chickens were less susceptible to intravenously administered E. coli than were the uninfected controls. Resistance of chickens that had been selectively bred for a high (HA) or low (LA) antibody response to sheep erythrocytes was compared. HA chickens were more resistant to respiratory agents and less resistant to E. coli than LA line chickens. When the lines were exposed to respiratory disease followed by exposure to aerosols containing E. coli, the HA line had the lowest incidence of pericarditis and death.

Effect of exposure to a short-duration sound on the stress response of chickens.

Chickens were subjected to the sound produced by banging on a metal pail (104 decibels) for 30 seconds. Heterophil/lymphocyte (H/L) ratios began to rise 18 hours later, reaching their maximum value (0.62) in 20 hours and returning to pre-stress values after 30 hours. Neither resistance to Escherichia coli challenge infection nor antibody response were altered.

Effects of ascorbic acid on stress and disease in chickens.

White leghorn chickens were given feed containing 100 mg of ascorbic acid (AA)/kg. One day later, treated chickens and a similar group of unmedicated control chickens were chilled for 1 hour at 6 C, exposed to an unusual sound, fasted, or subjected to rough handling. Heterophil:lymphocyte (H:L) ratios were determined one day later. The AA-treated birds had significantly lower H:L ratios than untreated controls. Chickens that received a diet containing AA had lower H:L ratios than controls (0.86 vs. 1.65) following administration of adrenocorticotropic hormone. Chickens fed a diet containing AA showed increased resistance to a combined Newcastle disease virus-Mycoplasma gallisepticum infection and to a secondary Escherichia coli infection, as well as to a primary E. coli challenge infection. The effects of AA and an antibacterial drug (furaltadone) were additive. In all experiments, the optimum dose of AA was 100 mg/kg of feed. There was a negative correlation between AA level in the diet and feed efficiency.

Effect of social environment and oocyst dose on resistance and immunity to Eimeria tenella challenge.

Chickens were exposed to graded doses of a suspension of Eimeria tenella oocysts while in environments of high (HSS) or low (LSS) social stress. Both primary cellular resistance and the sensitization phase of cell-mediated immunity were higher in the HSS environment than in the LSS environment. The manifestation of cell-mediated immunity seems to be inhibited by social stress.

Spleen lesions of hemorrhagic enteritis of turkeys.

Spleens from turkeys were examined at intervals after intravenous inoculation with hemorrhagic enteritis virus. Spleen size increased until the 4th day after inoculation. On the 5th day, spleen size was markedly reduced and continued to approach normal size. Hemorrhagic enteritis antigen reached a peak concentration on the 2nd day, was reduced in concentration on the 3rd day, and was absent by the 4th day. Hemorrhagic enteritis precipitin antibody was present in all serum samples taken after the 10th day. Necrosis of lymphoid cells in the white pulp was prominent in the 1st day. Proliferation of immature-appearing cells on the 2nd, 3rd, and 4th days coincided with a lower virus antigen content in the spleen. Massive disintegration of the white pulp, associated with the appearance of small dense-staining lymphocytes, began on the 4th day. By the 5th day only the splenic arteries and the surrounding reticular cells remained. Restoration of normal-appearing white pulp was completed by the 8th day. No correlation was noted between splenic lesions and intestinal lesions. Many stages in the development of typical intranuclear inclusions were observed.

Effects of early environmental stresses on chicken body weight, antibody response to RBC antigens, feed efficiency, and response to fasting.

Stress early in life (SEL) by either overheating or water deprivation altered the responses of 4-to-18-week-old chickens selectively bred for high (HA) or low (LA) antibody response to sheep RBC. When unstressed, HA birds weighed more than LA birds. Following SEL, LA birds weighed more than HA birds. Antibody response following SEL was decreased in HA birds and increased in LA birds. Both SEL and adaptation to handlers (AH) decreased the deleterious effects of fasting on antibody response to RBC antigens. Chickens subjected to SEL had a lower rate of gain following fasting. Adaptation to handlers tended to increase antibody response more in HA than in LA birds, while SEL tended to increase antibody response more in LA than in HA birds. Feed efficiency (FE) was increased by AH. A SEL resulted in increased FE of unadapted birds and decreased the FE of AH birds.

Adaptation of chickens to their handler, and experimental results.

Chickens were adapted to their handler before the experiment. Adapted birds produced more antibody, had more blood protein, gained more weight, and were more resistant to Mycoplasma gallisepticum than unadapted birds. The antibody response to sheep red blood cells was not reduced for fasting for 48 hours in adapted birds but was in unadapted birds. Differences in antibody titers, blood protein, and weight gains between controls and birds fed 80 ppm of deoxycorticosterone could be demonstrated only with adapted birds.

Effects of initial and second periods of fasting on heterophil/lymphocyte ratios and body weight.

Chickens that had never been without food or water were subjected to feed deprivation of 2 days duration on successive weeks. Both periods of feed deprivation resulted in similar reductions in body weight. The first period of feed deprivation resulted in a much more severe heterophil/lymphocyte ratio response to stress than the second period of feed deprivation. When the initial fast was followed 1 week later by 2 days of water deprivation, the heterophil/lymphocyte ratio response was similar to that of a similar flock of chickens that did not fast before the period of water deprivation.

Hemorrhagic enteritis of turkeys. Antiserum -- efficacy, preparation, and use.

Intestinal and splenic lesions of experimentally produced hemorrhagic enteritis of turkeys were prevented by administering convalescent antiserum. Protection varied with antiserum quality and time of administration after infection. In general, 1.0 to 0.5 ml per poult prevented all lesions and as little as 0.25 to 0.1 ml prevented intestinal lesions when administered within 48 hours of injection of the virus inoculum. Adding phenol to antiserum did not reduce its effectiveness. Convalescent antiserum was useful in controlling field hemorrhagic enteritis.

Long-term exposure of chickens to three levels of social stress.

Cockerels were kept in environments characterized by high (HSS), medium (MSS), or low (LSS) levels of social stress for 3 or 4 months. Chickens raised in an environment of low light intensity (LSS) gained more weight than did those raised under natural lighting. Ability of chickens to produce antibody in response to antigen was greatly reduced, 2(15.4) in the LSS group to 2(3.4) in the HSS group, 1 day after chickens were moved from the LSS environment into the HSS environment. Normal responsiveness returned within 1 week. No long-term environments affected antibody production. After 3 months, chickens in the LSS environment had reduced weight gain and resistance to Escherichia coli infection compared with birds in the HSS environment. Chickens in the MSS environment, compared with those on the HSS and LSS environments, had greater weight gains, superior feed efficiencies, medium plasma corticosterone levels, a better negative correlation between antibody responsiveness and RBC antigens, and better resistance to Mycoplasma gallisepticum challenge. All parameters except antibody responsiveness were such that long-term exposure to HSS or LSS environments appears to be detrimental.

Evaluation of the heterophil/lymphocyte ratio as a measure of stress in chickens.

The number of lymphocytes in chicken blood samples decreased and the number of heterophils increased in response to stressors and to increasing levels of corticosterone in the chicken feed. The ratio of heterophils to lymphocytes was less variable than the number of heterophil or lymphocyte cells, and the range of values for this ratio was greater than the range of values for heterophils and lymphocytes among control and experimental groups. The heterophil/lymphocyte ratio appears to be a more reliable indicator of levels of corticosterone in the feed and to social stress than were the plasma corticosteroid levels.

A surgical method for controlling the flight of peafowl (Pavo cristata).

The articular surfaces of the left humerus-ulna joint were curetted, and a surgical screw was inserted across the joint through the ulna and humerus. The joint was immobilized for 2 weeks. Treated peafowl could strut normally but could not cross a 1.3-meter fence.