Interactive effects of light-sources, photoperiod, and strains on growth performance, carcass characteristics, and health indices of broilers grown to heavy weights1.

Effects of light sources, photoperiods, and strains on growth performance, carcass characteristics, and health indices of broilers grown to heavy weights (>3 kg) were evaluated. The experimental design was a 4 × 2 × 2 factorial treatments consisting of 4 light sources [incandescent (ICD, standard), compact fluorescent light, neutral light emitting diode (Neutral-LED), and cool poultry specific LED (Cool-poultry specific (PS)-LED)], 2 photoperiods (regular/intermittent [2L:2D], and short [8L:16D]), and 2 strains (A, B). In each trial, chicks of 2 different strains from different commercial hatcheries were equally and randomly distributed into 16 environmentally controlled rooms at 1 D of age. Each room was randomly assigned one of 16 treatments from day 1 to 56 D of age. Feed and water were provided ad libitum. Birds were provided a 4 phase-feeding program (starter, grower, finisher, withdrawal). Birds and feed were weighed on 1, 14, 28, 42, and 56 D of age for growth performance. On day 56, a total of 20 (10 males and 10 females) birds from each room were processed to determine weights and yields. The BW, BW gain, live weight, and carcass weight of birds reared under PS-LED were higher (P < 0.05) in comparison with birds reared under ICD, but feed intake, feed conversion ratio, mortality, and carcass characteristics were not affected by treatments. Also, broilers subjected to the short/non-intermittent photoperiod had the lowest (P < 0.05) growth performance and carcass characteristics compared with values obtained for regular/intermittent photoperiods. In addition, strain was significant (P < 0.05) for most of the examined variables. Feed conversion, fat, tender, and yield were not affected by treatments. There was no effect of photoperiod, light sources, or their interactions on mortality. This study shows positive impacts on alternative light sources when compared to ICD along with regular/intermittent photoperiod in commercial poultry facilities rearing the 2 strains used in this study, thereby reducing energy costs and optimizing production efficiency without compromising the welfare of broilers grown to heavy weights.

Influence of light sources and photoperiod on growth performance, carcass characteristics, and health indices of broilers grown to heavy weights.

Effects of light sources and photoperiod on growth performance, carcass characteristics and health indices of broilers were investigated in 4 trials. In each trial, 720 1-day-old Ross × Ross 708 chicks were randomly distributed into 12 environmentally controlled rooms (30 males/30 females/room). The experimental design was a 4 × 3 factorial treatments consisted of 4 light sources [incandescent (ICD, standard), compact fluorescent (CFL), neutral light-emitting diode (Neutral-LED), and cool poultry-specific filtered LED (Cool-PSF-LED)] and 3 photoperiods [long/continuous (23L:1D), regular/intermittent (2L:2D), and short/non-intermittent (8L:16D)] from d8-d56. Birds were fed the same diet, while feed and water were provided ad libitum. Birds and feed were weighed on 1, 14, 28, 42, and 56 d of age for growth performance. Mortality was recorded daily and feed conversion was adjusted for mortality. Immune response was determined on d 28 to 35, whereas other welfare indices were performed on d 42, 43, and 49. At 56 d of age, 10 male and 10 female birds from each room were randomly selected and processed to determine weights and yields. The BW, BW gain, live weight, and carcass weights and yields of birds reared under Cool-PSF-LED were increased (P ≤ 0.05) in comparison to birds reared under ICD, but FI, FCR, and mortality were not affected. Moreover, broilers subjected to the short/non-intermittent photoperiod had the lowest (P ≤ 0.05) BW, BW gain, FI, live weight, carcass weight, and pectoralis major and minor weights compared to other 2 photoperiods. There was no effect of treatments on some carcass characteristics. There was no effect of treatments on welfare indices, suggesting that the light sources evaluated did not compromise welfare of heavy broilers. It was concluded that the 3 light sources evaluated in this study may be suitable for replacement of ICD light source along with regular/intermittent photoperiod instead of long/continuous photoperiod in poultry facilities to save energy utilization, thereby reducing the total cost of production.

Effects of light sources and intensity on broilers grown to heavy weights. Part 1: Growth performance, carcass characteristics, and welfare indices.

This study investigated the effects of light sources and light intensity on growth performance, carcass characteristics, and welfare indices of heavy broilers (>3.0 kg) in 4 trials with 2 replications per trial. A total of 960 one-day-old Ross×Ross 708 chicks (30 males/30 females/room) were randomly distributed into 16 environmentally controlled rooms at 50% RH. A 4×2 factorial treatment structure evaluated 4 light sources (incandescent [ICD, standard], compact fluorescent [CFL], neutral light emitting diode [Neutral-LED], and cool poultry specific filtered LED [Cool-PSF-LED]) and 2 levels (5 lx, 20 lx) of light intensities. Each of the 4 light sources was paired with one of the 2 light intensities. Birds were fed the same diet with a 4-phase feeding program (starter, grower, finisher, and withdrawal). Feed and water were provided ad libitum. Birds and feed were weighed on one, 14, 21, 28, 42, and 56 d of age for growth performance. All mortality was recorded daily and feed conversion was adjusted for mortality. Immune response was determined on d 28 to d 35, whereas other welfare indices were performed on d 42 and 49, respectively. At d 56 of each trial, 20 (10 males and 10 females) birds from each room were processed to determine weights and yields. The BW, BW gain, live weight, and carcass weights of birds reared under Cool-PSF-LED were different (P≤0.05) in comparison to birds reared under ICD. However, FI, FCR, and mortality were not affected by treatments. There was no effect of treatments on fat or breast and tender weights and yields. In addition, there was no effect of treatments on ocular development, immune response, and other welfare indices, suggesting that the light sources evaluated did not compromise welfare of heavy broilers. It was concluded that the 3 light sources evaluated in this study may be suitable for replacement of ICD light source in poultry facilities to reduce energy cost and optimize production efficiency.

Effects of strain and light intensity on growth performance and carcass characteristics of broilers grown to heavy weights.

Effects of genetic strain and light intensity on growth performance and carcass characteristics of broilers grown to heavy weights were investigated. The experimental design was a randomized complete block design. Treatment structure was a 2 × 5 factorial arrangement with the main factors being strain (Ross × Ross 308, Ross × Ross 708) and light intensity (25, 10, 5, 2.5, and 0.2 lx) with trial as replicates. In each of the 5 trials, chicks of 2 different strains of the same commercial hatchery were equally and randomly distributed into 10 environmentally controlled rooms (5 rooms/strain) at 1 d of age at 50% RH. Each room was randomly assigned 1 of 5 light intensities from 22 to 56 d of age. Feed and water were provided ad libitum. Birds and feed were weighed on 0, 14, 28, 42, and 56 d of age for growth performance. Humoral immune response was determined on d 28, whereas ocular and blood samples were performed on d 42 and 55, respectively. On d 56, 20 (10 males and 10 females) birds/strain from each room were processed to determine weights and yields. Genetic strain was significant (P ≤ 0.05) for most of the examined variables, where Ross × Ross 308 had better growth performance and meat yield in comparison with Ross × Ross 708. Although, there was no main effect of light intensity on growth performance and meat yield, results indicated that birds under 10 and 5 lx intensities showed slightly better growth performance and meat yield compared with birds under 25, 2.5, and 0.2 lx in both strains. There was no effect of strain and light intensity on ocular indices, immune response, plasma corticosterone levels, and mortality. This study shows the positive influence on profits to commercial poultry facilities that are using a low lighting environment to reduce energy cost, optimize feed conversion, and maximize production without compromising the welfare of the broilers.

Update on the effects of a sierran wildfire on surface runoff water quality.

Wildfire has been shown to increase the short-term (1-3 yr) mobilization of mineral N and P in forest ecosystems of the Sierra Nevada Mountains and Lake Tahoe Basin. The ensuing effects on tributary and lake water quality are uncertain. The purpose of this investigation was to assess the impacts on runoff water quality over an intermediate time frame of 5 yr (2002-2007) after a wildfire event. Our design included fixed plots randomly placed within burned and unburned areas. Because each plot was sampled repeatedly during the study, we treated plots as repeated random effects in the analysis. We used a mixed model approach to analyze nutrient runoff concentrations and load for NH-N, NON and P in phosphate form (designated as ortho P or PO-P) where treatment (unburned vs. burned), time (pre-wildfire, post-wildfire year 1, year 2, etc.), and their interaction were fixed effects. Concentrations and loads of mineral N and P were higher in runoff from the burned areas immediately after wildfire. Because high water years may also contribute to higher runoff nutrient concentrations and loading, a wildfire followed by a high water year within the first season after a wildfire would likely have a much greater impact on runoff (and hence tributary) water quality than a wildfire followed by a low runoff water year.

Effects of mechanical harvest plus chipping and prescribed fire on Sierran runoff water quality.

Fire suppression in Sierran ecosystems creates a substantial wildfire hazard and may exacerbate nutrient inputs into Lake Tahoe by allowing the buildup of O horizon material, which serves as a source for high N and P concentrations in runoff water. The purpose of this study was to evaluate the effects of biomass reduction using cut-to-length mechanical harvest followed by chipping and controlled burning on surface runoff volume and water quality. Based on previous findings regarding N and P leaching flux and soil solution concentrations, we hypothesized that controlled burning and/or mechanical harvest with residue chipping does not increase inorganic N, P, and S concentrations in overland flow. Runoff, snowmelt, and rainfall were collected, volume measurements were taken, and samples were analyzed for NO(3)-N, NH(4)-N, PO(4)-P, and SO(4). Runoff volume, season, and year were identified as important parameters influencing overland flow nutrient concentrations and loads. Higher nutrient concentrations were commonly associated with summer rather than winter runoff, but the opposite was true for nutrient loads due to the higher runoff volumes. Treatment (unharvested, harvested, unburned, burned) effect was a strong predictor for discharge loads of NO(3)-N and SO(4) but was a weak predictor for PO(4)-P. Discharge loads of NO(3)-N and SO(4) were greater for the unburned harvested and the burned unharvested treatments than for the unburned, unharvested control sites or the burned and harvested combined treatment. Although mechanical harvest and/or controlled burning had a small initial impact on increased nutrient loading, the effects were minimal compared with background levels. Hence, these management practices may have the potential to improve forest health without the danger of large-magnitude nutrient mobilization and degradation of runoff water quality found with wildfire.

Inorganic nitrogen and phosphorus in Sierran forest O horizon leachate.

High in situ concentrations of inorganic N and P have been reported in overland/litter interflow from Sierran forests, indicating that these nutrients are derived from the forest floor O horizons. To test this hypothesis, forest floor monoliths consisting of the combined O(e) and O(i) horizons were collected near the South Shore of Lake Tahoe, Nevada, for leaching experiments. Three monoliths were left intact, and three were hand-separated according to horizon for a total of three treatments (combined O(e)+O(i), O(e) only, and O(i) only) by three replications. Samples were randomized and placed into lined leaching bins. Initial leaching consisted of misting to simulate typical early fall precipitation. This was followed by daily snow applications and a final misting to simulate spring precipitation. Leachate was collected, analyzed for NH(4)(+)-N, NO(3)(-)-N, and PO(4)(3-)-P, and a nutrient balance was computed. There was a net retention of NH(4)(+)-N, but a net release of both NO(3)(-)-N and PO(4)(3-)-P, and a net release of inorganic N and P overall. Total contributions (mg) of N and P were highest from the O(e) and O(e)+O(i) combined treatments, but when expressed as per unit mass, significantly (p < 0.05) higher amounts of NO(3)(-)-N and PO(4)(3-)-P were derived from the O(i) materials. The nutrients in forest floor leachate are a potential source of biologically available N and P to adjacent surface waters. Transport of these nutrients from the terrestrial to the aquatic system in the Lake Tahoe basin may therefore play a part in the already deteriorating clarity of the lake.

Ocular responses to ammonia in broiler chickens.

In two trials, 60 male commercial broilers were placed in each of eight environmentally controlled chambers receiving 0, 25, 50, or 75 ppm aerial ammonia from 1 to 28 days. Birds exposed to 25 ppm (lower concentration) ammonia gas developed ocular abnormalities but at a slower rate when compared with birds exposed to 50 and 75 ppm (higher concentrations). Birds exposed to higher concentrations also developed more severe lesions. With little atmospheric ammonia present after 28 days of the grow-out stage, the corneas indicated signs of healing. Lymphocytes and heterophils were seen in the iris at 49 days in ammonia-exposed birds even when ammonia exposure was terminated at 28 days. The lower ammonia concentrations resulted in abnormalities that were slight when compared with those seen at the higher ammonia concentrations. As measured by the incidence of inflammatory infiltrates in the trachea, lung, and air sacs, respiratory tract tissues did not appear to be affected by any tested level of aerial ammonia. The findings in this investigation represent the first report indicating that ammonia-induced uveitis in chickens clears rapidly after exposure to ammonia ceases.

Wildfire effects on soil nutrients and leaching in a tahoe basin watershed.

A wildfire burned through a previously sampled research site, allowing pre- and post-burn measurements of the forest floor, soils, and soil leaching near Lake Tahoe, Nevada. Fire and post-fire erosion caused large and statistically significant (P < or = 0.05) losses of C, N, P, S, Ca, and Mg from the forest floor. There were no statistically significant effects on mineral soils aside from a decrease in total N in the surface (A11) horizon, an increase in pH in the A11 horizon, and increases in water-extractable SO4(2-) in the A11 and A12 horizons. Burning caused consistent but nonsignificant increases in exchangeable Ca2+ in most horizons, but no consistent or statistically significant effects on exchangeable K+ or Mg2+, or on Bray-, bicarbonate-, or water-extractable P concentrations. Before the burn, there were no significant differences in leaching, but during the first winter after the fire, soil solution concentrations of NH4+, NO3-, ortho-P, and (especially) SO4(2-) were elevated in the burned area, and resin lysimeters showed significant increases in the leaching of NH4+ and mineral N. The leaching losses of mineral N were much smaller than the losses from the forest floor and A11 horizons, however. We conclude that the major short-term effects of wildfire were on leaching whereas the major long-term effect was the loss of N from the forest floor and soil during the fire.

Evaluation and management of corneal ulcerations: a systematic approach.

Corneal ulceration is a common condition in companion animal practice. A thorough understanding of corneal anatomy and physiology is essential to making an accurate diagnosis and treatment selection. A method of categorizing corneal ulcers based on location, response to treatment, and severity will aid the clinician in record keeping and judging the response to treatment.

Modulation of proteolytic activity associated with persistent corneal ulcers in dogs.

Canines affected with corneal lesions demonstrate increased proteolytic activity at the affected site. Canines that develop persistent corneal ulcers and maintain elevated levels of proteolytic activity respond to protease inhibitor therapy with polysulpated glycosaminoglycan, PSGAG. In this study, the proteolytic activity expressed in lacrimal fluid of canines was evaluated as normal (1.15 U mL-1) or healed (1.19 U mL-1). Six of the 26 dogs affected with persistent corneal ulcers, however, had a protease level consistent with the unaffected control animals. These dogs did not appear to respond to PSGAG therapy. Two pathophysiologies for persistent corneal ulcers are indicated. Identifying which mode is active could help determine the therapeutic treatment needed.

Sensorineural hearing loss associated with Kawasaki disease.

In five children who met the diagnostic criteria for Kawasaki Disease, sensorineural hearing loss developed in association with the acute illness. The children, aged 7 months to 13 years, had deficits ranging from mild to profound bilateral sensorineural hearing loss. There were no associated neurologic abnormalities, and immunologic investigations and magnetic resonance imaging failed to reveal a cause. Treatment regimens differed among the children, but none had high salicylate levels (greater than 20 mg/dl) or received other ototoxic medications. Antiinflammatory therapy was not obviously beneficial in any case, and four of the children have persistent hearing deficits. We conclude that auditory involvement may be a complication of Kawasaki disease; screening of clinically affected children should be considered.

Progress in the development of a fluorescent intravascular blood gas system in man.

In vitro and in vivo animal studies have shown accurate measurements of arterial blood pH (pHa), carbon dioxide tension (PaCO2), and oxygen tension (PaO2) with small intravascular fluorescent probes. Initial human clinical studies showed unexplained intermittent large drops in sensor oxygen tension (PiO2). Normal volunteers were studied to elucidate this problem. In the first part of this study, the probe and cannula were manipulated and the probe configuration and its position within the cannula were varied. The decreases in PiO2 were judged to be primarily due to the sensor touching the arterial wall. Retraction of the sensor tip within the cannula eliminated the problem. In the second part of this study, the accuracy of the retracted probe was evaluated in 4 subjects who breathed varying fractions of inspired oxygen and carbon dioxide. The arterial ranges achieved were 7.20 to 7.59 for pH, 22 to 70 mm Hg for PaCO2, and 46 to 633 mm Hg for PaO2. Linear regression of 48 paired sensor (i) versus arterial values showed pHi = 0.896 pHa + 0.773 (r = 0.98, SEE = 0.017); PiCO2 = 1.05 PaCO2 - 1.33 (r = 0.98, SEE = 2.4 mm Hg); and PiO2 = 1.09 PaO2 - 20.6 (r = 0.99, SEE = 21.2 mm Hg). Bias (defined as the mean differences between sensor and arterial values) and precision (SD of differences) were, respectively, -0.003 and 0.02 for pHi, 0.77 and 2.44 mm Hg for PiCO2, and -2.9 and 25.4 mm Hg for PiO2. The mean in vivo 90% response times for step changes in inspired gas were 2.64, 3.88, and 2.60 minutes, respectively, for pHi, PiCO2, and PiO2.

Postnatal development of the photoreceptor inner segment of the retina in dogs.

In dogs, the retina develops during the postnatal period in a manner similar to that in other animals born with closed eyelids. Photoreceptor inner segments are initially observed as a cytoplasmic bulge protruding sclerad through the external limiting membrane. Outer segment formation begins when a centriole within the inner segment attaches to the distal inner segment cell membrane. A few round mitochondria are observed within the early inner segments. As maturation proceeds, the number of mitochondria within the inner segments increases and the mitochondria elongate, orienting parallel to the long axis of the inner segment.

Acid alpha-neuraminidase deficiency: a nephropathic phenotype?

Isolated neuraminidase deficiency is a member of the relatively rare group of storage disorders known as glycoproteinoses. We report the long-term natural history of the disease in one of the first patients described in the literature. An unusual feature of the disease is the abrupt onset and fulminant nature of the nephrotic syndrome, complications of which caused the demise of our patient. Pathological examination of the kidneys from this child revealed renal epithelial cell damage, most marked in the membranes of the glomeruli and proximal tubules, findings which are consistent with the high sialic acid content of the membrane in these areas of the nephron. Chemical analysis indicated that the bulk of the stored material in the kidney was in the form of polar sialyloligosaccharides of high molecular weight. On the basis of our experience, as well as the previous reports of neuraminidase-deficient patients with nephropathy, we propose a nephropathic phenotypic variant of type 2 infantile sialidosis.

Granulomatous uveitis in an owl.

Granulomatous lens-induced uveitis was diagnosed in a mature male barred owl. Initial ocular examination revealed a large white mass in the left eye. Differential diagnoses for the mass included intraocular granuloma, neoplasia, foreign body, bacterial or fungal enophthalmitis, and fibrotic hematoma. After enucleation of the left globe, histologic examination revealed the mass to be a granulomatous inflammatory reaction to a posteriorly luxated, traumatized lens. Lens-induced uveitis should be considered whenever a bird has suffered lenticular trauma.

Performance of an in-vivo, continuous blood-gas monitor with disposable probe.

A fluorescence-based fiber optic measurement system has been developed for monitoring pH, pCO2, and pO2 through a 20-gauge radial artery catheter without compromising capabilities for monitoring arterial pressure or for blood withdrawal. The measuring probe consists of three optical fibers to which the sensing chemistries are attached, and a thermocouple that measures temperature. The probe is designed to meet in-vivo biocompatibility requirements for a one-time use of up to 72 h. The components that are in contact with the patient's blood are nontoxic, nonhemolytic, nonthrombogenic, and sterilizable. Blood compatibility is enhanced by including covalently bound heparin. The in-vitro accuracy of the system has been tested against commercial blood-gas measurement instruments; comparison with tonometry and blood gas values gave r greater than or equal to 0.98 for all three sensors. The standard error for all sensors was within the College of American Pathologists' accuracy guidelines for measuring blood gas. Instrumental drift was minimal, indicating that system performance characteristics should not be the limiting factor in obtaining clinically useful information for up to 72 h. The response times of the sensors in animal and in-vitro studies were less than 2 min, suitable for monitoring physiological changes in blood gas values.