Biomedical subjects
Publications and source records attributed to D M Janky.
The effect of age on the yolk:albumen (Y:A) ratio was studied for eggs obtained from Hy-Line W36 and Arbor Acres hens. Albumen weight was more closely associated with egg weight (EW) than yolk weight for both commercial layers and broiler breeder hens. A small positive relationship between EW and Y:A ratio was found. A significant increase in Y:A ratio was evident in older flocks from both breeds.
A staining procedure used for simultaneously determining three different fiber types in single sections of bovine, porcine, or ovine skeletal muscle was modified for use with broiler skeletal muscle. The modification involved acid-preincubation of muscle sections at a pH of 4.15 followed by staining for reduced nicotinamide adenine dinucleotide (NADH) tetrazolium reductase enzyme and for acid-stable myosin-adenosine triphosphatase enzyme activity, respectively. Four broiler muscles were selected for fiber-type determination of fast (alpha), slow (beta), red, aerobic (R), or white, anaerobic (W) properties. The anterior latissimus dorsi muscle was composed almost entirely of beta-R fibers while the pectoralis superficialis muscle was composed almost entirely of alpha-W fibers. The sartorius and posterior latissimus dorsi muscles were much more heterogeneous in fiber-type distribution, exhibiting all three types of fibers (alpha-W, alpha-R, and beta-R).
Alternate white and yellow layers in the yolk are described in most textbooks. However, it was impossible to distinguish the presence of these layers when hard-cooked yolks from hens fed commercial type diets were examined. Serum xanthophyll concentrations were measured at different times during a 24-h period. Concentrations did not vary significantly due to time of day.
Two experiments were conducted using 21-day-old, commercial-strain broilers to determine the effect of various commercial pigmentation products on pigmentation and bird performance. Birds received finisher/withdrawal diets that included 8% corn gluten meal or either a 2.5 or 5.0% substitution of gluten meal with Liquid OroGlo5, Dry Oroglo10, or Cromophyl-oro. When birds were slaughtered at either 48 or 51 days of age there were no differences in the birds' breast skin hue (dominant wavelength) or brightness (luminosity). Data indicated similar levels of pigmentation among birds in all treatments. Color intensity (excitation purity) values of shank and breast skin samples suggested that the liquid form of OroGlo was more effective than the dry form in pigmenting broiler skin when both forms were fed at equal calculated levels. Data indicated that actual xanthophyll intake was higher when the liquid source was fed. Body weight gain and feed efficiency among the treatments, in general, indicated that commercial pigment sources can be substituted for corn gluten meal without appreciably altering broiler performance.
An experiment was conducted to determine the effect of dietary Virginiamycin on processing yields of broilers fed four levels of energy. Body weights (catch, slaughter) and carcass weights (dry shell and ready-to-cook) were recorded. Shrink (holding weight loss), water uptake, shell yield, and ready-to-cook yield of the carcasses were calculated. Body weights were higher at higher energy levels and with addition of Virginiamycin to the diets. Weight loss due to shrink declined from 5.39 to 3.89% at higher dietary energy levels, but shrink was not affected by Virginiamycin. Water uptake was significantly higher for carcasses of birds fed the lowest dietary energy level (3.49%) than for carcasses of birds fed the two highest energy levels (2.89 and 3.03%); but differences among water uptake of carcasses of birds fed the three highest energy levels were not significant. Water uptake was unaffected by Virginiamycin. Increasing the dietary energy level resulted in higher ready-to-cook yields, from 61.7% yield at 2,271 kcal ME/kg to 65.4% yield at 2,953 kcal ME/kg. Yield was increased from 63.3 to 64.0% (P less than .01) by dietary Virginiamycin.
A study was designed to determine whether wheat could be substituted for corn without reducing yolk quality and yolk membrane strength. Diets with either corn or Florida 301 wheat as the grain source were fed to 50-wk-old hens (140 per diet). Eggs were collected and stored at 10 C for up to 4 wk or at 23 C for 1 wk. At weekly intervals Haugh units, yolk index, yolk rupture strength, and yolk deformation distance at rupture were measured and compression percentages were calculated. Haugh units and yolk index were not affected by diet. Yolk rupture strength and deformation were 12.3% and 4.7% greater, respectively, for eggs from hens on the wheat diet than for those from hens on the corn diet. Both rupture strength and deformation declined significantly with storage. Eggs stored at 23 C were lower in yolk rupture strength and deformation than those held at 10 C. Percentage of compression at rupture also declined with storage, but the decline was initially more rapid for egg yolks from birds fed the corn diet than for egg yolks from birds fed the wheat diet. It was concluded that Florida 301 wheat may be substituted for corn without incurring any problems in the quality of the yolk and that yolk breaking strength would be enhanced.
Two experiments were conducted for five 28-day periods each. In Experiments 1 and 2, Hyline W-36 hens, 36 and 26 weeks of age, respectively, were used. Experiment 1 was designed to measure the effect of virginiamycin on hen performance and egg characteristics when supplementing a diet having low pigmentation potential. In Experiment 2, the diet contained 3% added fat with 0, 10, and 20 ppm virginiamycin. In Experiment 1, virginiamycin-supplemented hens showed increased (P less than or equal to .05) egg production, body weight, and improved feed efficiency. When egg production and feed efficiency were ranked by quartiles within the control and virginiamycin-supplemented groups, virginiamycin was shown to benefit only the poorer producing hens. In Experiment 2, added fat improved feed efficiency; however, the response to virginiamycin, as observed in Experiment 1, did not occur.
The possibility of beta-carotene affecting production of hens or hatchability of eggs was studied over 252 d with diets based on white maize containing 0, 1.5, 6.75 or 15 mg added beta-carotene/kg. Egg production, food intake, food utilisation, egg weight, and egg specific gravity were not affected significantly by beta-carotene. Egg fertility, hatchability and final body weights of hens were also not significantly influenced. Reflectance measurements showed that dietary beta-carotene resulted in increased deposition and more intense pigmentation in the egg yolk.
Two experiments were conducted with broilers to determine the effect of Virginiamycin supplementation on performance and shank pigmentation. Virginiamycin supplementation at 10 ppm resulted in significantly increased body weights in both experiments. Feed efficiency was significantly improved in Experiment 1 by the supplementation of 5 and 10 ppm Virginiamycin. In Experiment 2, 20 ppm Virginiamycin was included and resulted in no greater response than that observed at 10 ppm. Pigmentation values as measured by a reflectance colorimeter and Roche color fan favored (P less than or equal to .05) Virginiamycin supplementation in both experiments. Data indicated that when the diet was supplemented with Virginiamycin an increase in the utilization of xanthophyll resulted. Mortality was not influenced by dietary treatment.
Effects of storage at 5 ad -18 C for up to 28 days and high and low inoculation levels on survival of Salmonella infantis and Staphylococcus aureus on smoked broiler halves were investigated. S. infantis and Staph. aureus counts were significantly reduced during storage. The reduction in counts of S. infantis could not be attributed solely to either temperature or inoculation levels. Storage at 5 C significantly (P less than .05) reduced Staph. aureus counts on smoked broiler halves as compared to storage at -18 C. For Staph. aureus, low inoculation levels (10(3) to 10(4) organisms/ml) resulted in significantly higher mortality rates than did high inoculation levels (10(7) to 10(8) organisms/ml). At both storage conditions and inoculation levels, Staph. aureus was able to maintain higher populations than S. infantis.
White Leghorn hens, housed in cages were fed commercial-type corn-soy diets containing one of three levels of 3-Nitro-10 (0, .0025, and .005%) and either of two levels of xanthophyll (high and low) supplied by yellow corn. Egg yolks were collected and the yolks analyzed for color using reflectance colorimetry. The addition of 3-Nitro-10 at either level increased egg yolk dominant wavelength (DWL) and excitation purity (EP) values while decreasing luminosity (LUM) values (probability levels: .08, .10, and .003, respectively). It was concluded that the addition of 3-Nitro-10 to the diet of laying hens improved egg yolk color.
An experiment was conducted to determine the effect of different window coverings on broiler pigmentation. Equal numbers of male and female broilers were grown in open-type houses. The control house had open sides, while each treatment house had window coverings with either 42% or 89% light transmission properties. Birds from houses with window coverings deposited the same amount of pigment in the skin as did birds from the open house as indicated by blood xanthophyll level and excitation purity. Skin color scores, however, as well as dominant wavelengths and luminosities of shanks from these birds, indicated that pigmentation of birds grown in the house with 42% light transmission window coverings was significantly inferior to that observed for birds grown in either the open house or the house with 89% light transmission window covering. It was concluded that in situations where pigmentation is of concern, care should be taken in selecting window coverings which will not adversely affect pigmentation.