Biomedical subjects

J A Cason

Publications and source records attributed to J A Cason.

41 records · Page 3Linked to original sources

PubMed1993

Location of Salmonella typhimurium during incubation and hatching of inoculated eggs.

Location of Salmonella during hatching of broiler chicks was studied in three experiments. Unincubated, fertile hatching eggs heated to 42 C were inoculated by immersion for 15 min in a 16 C physiological saline solution containing approximately 1 x 10(5) cfu/mL of a nalidixic acid-resistant strain of Salmonella typhimurium. All eggs were sanitized externally by wiping with a paper towel wet with 70% ethanol. When incubating eggs were transferred to a hatcher, each was placed in a closed paper bag to minimize cross-contamination. Unhatched eggs were sampled by cutting away the shell over the air cell, sanitizing the inner air cell membrane with 70% ethanol, and removing the contents through the membrane. Shells and membranes were crushed and mixed in 10 mL buffered peptone (BP). Yolks were dissected out, dipped in 70% ethanol, and mixed with 10 mL BP. Embryos or chicks and all surrounding fluid were rinsed in 100 mL BP. A total of 172 eggs was sampled. Shells and membranes were 100% Salmonella-positive 30 min after inoculation, but only 38% were positive after 17 to 21 days of incubation. No chick rinses were positive before pipping, but 15% were positive after pipping. Yolk samples were 2% positive before pipping versus 8% after pipping. A majority of chicks hatching from positive shells and membranes were Salmonella-negative.

Animals↗

PubMed1988

Research note: effects of caponization on broiler growth.

The effect of caponization on growth of male broiler chicks was investigated in two experiments. Broiler chicks were caponized, sham-operated, or left as intact controls at 3 wk of age (Experiment 1) or 1 wk of age (Experiment 2). When processed at 7 wk of age, intact control broilers in both experiments were significantly heavier than sham-operated or caponized broilers, with no significant weight differences between sham-operated and caponized birds. However, the slope of growth rate in capons was significantly greater than that of sham-operated controls in Experiment 2. Capons also had significantly larger abdominal fat pads than did sham-operated controls.

Animals↗

PubMed1987

Influence of caponization on skin pigmentation of male broilers.

Two experiments were conducted to investigate the influence of caponization on skin pigmentation. Male broiler chicks were divided into caponized, sham-operated, and intact treatment groups with surgery performed at 3 weeks of age (Experiment 1) or 1 week of age (Experiment 2). All chicks were provided with corn-soy broiler diets ad libitum. In Experiment 2, an additional 37.4 mg of total xanthophyll was added per kilogram of finisher diet. At 7 weeks of age, birds were processed, comb size was scored, and the gonadal area was examined to identify partially caponized or improperly sexed birds. Caponized, sham-operated, and intact carcasses for analysis totaled, respectively, 28, 25, and 18 in Experiment 1 and 59, 33, and 30 in Experiment 2. Skin pigmentation was measured by reflectance colorimetry on the anterior portion of the lateral feather tract, on the same area of breast skin after removal from the carcass, and on shank skin removed from the leg. No differences were found in skin lightness (L), redness (a), or yellowness (b) between the treatment groups. These results indicate that pigmentation differences between male and female broilers are not likely to be due to differences in testicular activity.

Animals↗

PubMed1986

Effect of short-term feed deprivation on shell quality in laying hens.

Hens with feed withheld for 24 hr had poorer shell quality for the next 3 days. Hens with feed withheld for the first 8 hr (0400 to 1200 hr) of the 16-hr light cycle showed no decline in shell quality, but those with feed withheld the last 8 hr (1200 to 2000 hr) had poorer shell quality on the following day. When the period from 1200 to 2000 hr was divided into 2 periods (1200 to 1600 hr and 1600 to 2000 hr), feed restriction during the 1600 to 2000-hr period caused a decline in shell quality on the next day, but removal during the 1200 to 1600-hr period had no effect on shell quality. Shell quality was related to the feed intake of the hens, because about 34% of their feed intake was during the period 1600 to 2000 hr. Hens fed a low Ca diet (.7%) from 1200 to 2000 hr had poorer shell quality but not as poor as those with feed withheld. Feeding a high Ca diet (7.6%) from 0400 to 1200 hr prior to feed restriction from 1200 to 2000 hr, or giving oyster shell during the period of feed removal, improved shell quality, but not to the level of the full-fed birds. Daily feed restriction from 1200 to 2000 hr caused a reduction in shell quality for the first 4 days after which shell quality returned, but a slight decline in egg production was noted. These hens were able to consume approximately 70% of the feed consumed by the full-fed birds.

Animals↗

PubMedDate not supplied

Transmission of Salmonella typhimurium during hatching of broiler chicks.

Horizontal spread of Salmonella during hatching of broiler chicks was studied in three experiments. In each experiment, 120 unincubated, fertile hatching eggs were inoculated by immersion for 15 min in a 16 C physiological saline solution containing 1 x 10(8) colony-forming units per ml of a nalidixic-acid-resistant strain of S. typhimurium. When inoculated eggs were transferred to hatchers after 17 to 18 days of incubation, control eggs at the same stage of incubation were added to the same tray and to trays above and below the tray containing inoculated eggs. Fertile inoculated eggs hatched at a rate of 86%, despite the high level of Salmonella contamination, indicating that chicks in eggs contaminated with salmonellae are likely to hatch and may contaminate other chicks in the same hatcher cabinet. Air samples showed a sharp increase in contamination in the hatcher at 20 days of incubation. Approximately 58% of mouth swabs and 90% of chick rinses were Salmonella-positive, in both inoculated and control eggs. In samples from inoculated eggs, Salmonella was detected in the digestive tract of 8% of embryos at transfer from incubator to hatcher and in 55% of chicks at hatch. From control eggs, 44% of digestive tracts of hatched chicks were positive, indicating that Salmonella in a contaminated hatcher can reach the gut of chicks hatching from Salmonella-free eggs before they are removed from the hatcher.

Animal Husbandry↗