Active immunoglobulin (IgY) was isolated from egg yolk of chickens immunized with formalin-treated E. coli. The antibody activity was measured by enzyme-linked immunosorbent assay using E. coli lipopolysaccharide as an antigen. The anti-E. coli IgY aggregated the bacterial cells and inhibited their growth in rjit~a. IgY was rclativcly heat-stable without loss in antibody activity by pasteurization. IgY was stable at pH above 4, but was more susccptiblc to pepsin than bovine IgC, while apprcciablc activity was retained by IgY after trypsin-and chymotrypsin-digestion. It appears possible, therefore, to use IgY for the fortification of food products, especially infant formulae.

No abstract

Frrzsrlruor.qs, , R. C., Nnwcovsn, M. a.No Moul, I. E. 1989. The long-term effects of feeding ground and whole cottonseed to laying hens. Can. J. Anim. Sci. 69: 425-429.Laying hens were fed diets containing0,2.5,5, 10, 15 and 20% whole or ground cottonseed. Birds fed the 15 and 20% ground cottonseed diets rapidly reduced voluntary feed intake and, as a result, suffered a loss in both body weight and egg production. The severity of the dietary effects of cottonseed on productivity and mottled yolks was positively correlated with the level of cottonseed and gossypol in the diet. Egg yolk discoloration was assessed both visually on fresh yolks and using a time exposure to ammonia fumes. Discoloration was easier to detect using the ammonia test. In all cases, egg yolk discoloration was no longer apparent after a maximum of 42 d of feeding a commercial diet.

The effects of Freund's adjuvants on antibody production in chickens against E. coli whole cells were examined. The levels of anti-£. coli IgG antibodies in serum were higher when Freund's complete (FCA) or incomplete adjuvant (FIA) was administered than that without adjuvant. Production of antibodies recognizing E. coli cells and their lipopolysaccharide was enhanced by FIA, while both FIA and FCA enhanced production of antibodies recognizing outer membrane components. In contrast, serum IgM antibody levels were higher when no adjuvant was used. Anti-£. coli IgG antibodies in serum were efficiently transferred to egg yolk, giving antibody activity in egg yolk similar to that in serum. However, anti-£. coli IgM antibodies were not detected in the egg, suggesting that egg (white) IgM was not influenced by antigenic stimulation of the humoral immune system. Antimicrobial activity of the egg yolk IgG was highest when the bacteria antigen was injected with FIA.

Shaver Starbro broiler breeder pullets were used to study the effect of day length (24 and 28 h) on egg production parameters and egg traits from 22 to 30 wk of age, and ovarian and morphological characteristics at 30 wk of age. Floor-housed pullets were raised in a light-tight facility from 1 d of age until housing in individually illuminated cages at time of photostimulation (22 wk). Cages were equipped with hardware to monitor egg laying time. The photoschedule during rearing was 24 h light: 0 h dark for the first 3 d followed by 8 h light: 16 h dark from 3 d to photostimulation. Body weight was monitored throughout the trial to maintain weights at targets set by Shaver Poultry Breeding Farms, Ltd. The experimental design was a 2 x 2 factorial with two day lengths [hemeral (24 h) and ahemeral (28 h)] and two BW groups [high (HBW) and low BW (LBW)], with the LBW weighing 327 g less than the HBW birds at 22 wk of age. The hemeral photoschedule was 14 h light: 10 h dark, and the ahemeral photoschedule was 14 h light: 14 h dark. Differences in BW remained throughout the trial. Egg numbers were not increased by the 28-h day (24 h = 25.4 eggs; 28 h = 23.1 eggs). The 24-h hens laid more double-yolked eggs (0.9% of total egg production) than did the 28-h birds (0.3%). Egg formation time was consistently longer for the 28-h hens (26.8 h at 25 wk of age and 25.8 h at 29 wk of age) compared with the 24-h hens (25.4 h at 25 wk of age and 24.8 h at 29 wk of age). Mean egg weight was higher for the 28-h birds (55.1 g) compared with the 24-h birds (53.0 g). Egg specific gravity was higher in eggs from the 28-h hens than eggs from the 24-h hens. Some of the increase in egg weight between the 28- and 24-h birds was due to shell weight. Absolute and proportional weights of the egg shell were 5.5 g and 10.0% of the total egg weight for the 28-h birds and 4.9 g and 9.3% for the 24-h birds, respectively. The 28-h hens had higher proportional breast muscle weight, smaller livers and oviducts, and lower ovary weight compared with the 24-h birds. The data indicated that, although egg size can be increased with the use of long ahemeral days early in lay, this result may be at the expense of egg numbers. Early in lay, follicular maturation rates are fast, and egg production may be limited to one ovulation per 28 h.