Selection of poultry for fast growth rate is often accompanied by a reduction in specific immune responses or increased disease susceptibility. In this study, 17-wk-old male turkeys from each of four closed genetic lines, a randombred control (RBC) line and its subline (F) selected for increased 16-wk BW, and another RBC and its subline (E) selected for increased egg production, were tested for in vivo response to toe web inoculation with phytohemagglutinin-P (PHA-P), in vitro response of lymphocytes in whole blood to PHA-P and concanavalin A (Con A), hemolytic complement activity, differential white blood cell counts, hematology, and serum chemistry values. Fifteen male turkeys from each of two commercial lines, Com A and Com B, were also tested. The large-bodied F line birds had a lower toe web response to PHA-P, lower lymphocyte counts, and lower relative spleen weights than their smaller parent line. Body weights, total erythrocyte counts, blood urea nitrogen (BUN) levels, and in vitro mitogenic response to PHA-P and Con A were higher in the F line birds. Line E had lower hemolytic complement levels, lower relative spleen and relative bursal weights, and a higher in vitro mitogenic response to PHA-P than its parent line. The Com B line had a lower toe web response to PHA-P, and lower serum levels of gamma-glutamyltransferase and bilirubin than Com A. Line Com B had higher total RBC counts and higher levels of alanine aminotransferase (ALT) than Com A. These results support the concept that some changes in the cell-mediated immune response, as well as other physiological changes that may potentially affect immune response, appear to accompany selection for faster growth.

Proventriculitis is a problem affecting the processing of broiler carcasses, particularly those processed at 4 to 5 wk of age. The proventriculus and the gastric isthmus connecting the proventriculus to the gizzard are enlarged and swollen and often rupture during processing, causing carcass contamination. This study suggested that a filterable agent found in homogenated proventriculi can cause lesions similar to those seen in field cases. Proventriculitis was produced independently of an effect on growth, and only unfiltered homogenate caused stunting. Field birds with severe proventriculitis were shown to have increased body weights compared with birds without proventriculitis or with milder lesions. Intestinal weakness was not associated with proventriculitis and field birds with the most severe proventriculitis had stronger intestines. Although infectious proventriculitis has generally been reported as one of the lesions associated with stunting syndrome, these data suggest that it may have an independent etiology.

The use of intermittent lighting in broiler production has been shown to result in spurts of activity that appear to reduce lameness. Because intermittent lighting is difficult to achieve in curtain-sided houses, the objective of this study was to determine whether simple equipment used to increase activity in broilers would improve production variables. At 1 d of age, 840 male broiler chicks were placed in 24 floor pens. The four treatments (six replicates of 35 chicks each) were as follows: 1) Control-standard feeders, 2) Ramps and Toys-birds had to climb a slight incline ramp to reach feeder and had a hanging mobile, 3) Ramps only, and 4) Toys only-standard feeders. Two trials were conducted. Weekly group weights and feed consumption were recorded. Mortality was recorded daily. At 6 wk of age, birds were bled, euthanatized, weighted, and scored for ascites and tibial dyschondroplasia (TD), and relative heart, liver, and spleen weights were obtained. Blood samples were analyzed for blood gases, hemoglobin, red blood cell count, and clinical chemistries were performed. In Trial 1, during Weeks 2, 3, and 4, treatments with ramps had significantly heavier average bird weight and significantly lower feed:gain ratios. In Trial 2, treatments with ramps had no difference in average BW; however, these groups consumed less feed, resulting in significantly lower feed:gain ratios. Cumulative mortality was decreased by ramp treatment in Trial 2. Toys decreased the incidence and severity of TD in Trial 2. In general, organ weights, blood gases, hematologies, and clinical chemistries were not affected by treatments. However, birds in treatments with ramps had significantly lower serum calcium and smaller hearts in Trial 1, and significantly lower serum cholesterol and smaller hearts in Trial 2.

The effect of microaerosolized H2O2 on bacterial and viral poultry pathogens was investigated. Bacterial cultures and viruses were dried on sterile glass Petri dishes and subjected to direct and indirect 5% (H2O2) microaerosol mist. In the trials using Escherichia coli and Staphylococcus aureus, there was complete inactivation following exposure to H2O2. Using Salmonella typhimurium, indirect exposure resulted in only partial inactivation whereas direct exposure to H2O2 gave complete inactivation. For the viruses studied, 5% H2O2 microaerosol mist completely inactivated infectious laryngotracheitis virus. Newcastle disease virus, infectious bronchitis virus, and avian influenza virus showed reduced infectivity but were not completely inactivated. Avian reovirus susceptibility varied with the method of exposure and infectious bursal disease virus was highly resistant. The use of 10% H2O2 mist, however, resulted in total inactivation of infectious bursal disease virus. The effect of 10% H2O2 on equipment and selected materials representative of a hatcher or poultry house was investigated. A solar cell calculator, a thermostat containing a microswitch, and samples of uncoated steel, galvanized steel, and uncoated aluminum were subjected to 10 fumigation cycles. No damage was detected in the calculator and the thermostat. Both the uncoated steel and the galvanized steel showed signs of oxidation. The aluminum did not show signs of oxidation.

A study of field turkeys was undertaken in order to determine the involvement of relative immunological differences in the etiology of turkey osteomyelitis complex (TOC). Lame and normal turkeys were sampled from commercial flocks just prior to processing in two separate trials. After testing for functions of both humoral and cellular immunity, the turkeys were necropsied and examined for lesions of TOC. There were significantly higher relative spleen and over weights and significantly lower body weights and relative bursal weights in birds with TOC. The birds with TOC had lower response to phytohemagglutinin-P in both in vivo and in vitro tests as well as lower circulating lymphocyte counts and higher monocyte, heterophil, and total white blood cell counts. There was a significantly higher antibody response to sheep red blood cells in turkeys with TOC, whereas antibody response to Salmonella pullorum antigen was not different. There were no significant differences in the percentages of mononuclear cells or heterophils able to phagocytize bacteria or latex particles, or kill bacteria; however, the heterophils from turkeys with TOC lesions did phagocytize significantly fewer latex particles per cell than did those of the healthy turkeys. Total serum protein, uric acid, and blood urea nitrogen levels were higher in birds with TOC, whereas hemoglobin, iron, alkaline phosphatase, and gamma-glutamyl-transferase levels were lower. Although many of the differences in birds with TOC could be caused by the normal host reaction to infection, further study may reveal innate differences that contribute to susceptibility to TOC.