Effects of in ovo administration of L-carnitine on hatchability performance, glycogen status and insulin-like growth factor-1 of broiler chickens.

1. Eggs from a meat-type breeder flock (Ross) were used in two trials to study the effects of in ovo administration of L-carnitine (carnitine) on hatchability traits (hatchability percentage, embryo deaths, pipped with live or dead embryo), chick weight at hatch as an absolute value (CWT) or expressed as a percentage of egg weight (CWT%), hatching period, glycogen status (liver and pectoral muscle) and plasma insulin-like growth factor-1 (IGF-1) of hatched chicks were investigated. There were 9 treatments with three replicates of each. Treatments were non-injected control (negative control), or injection with sterilised saline (09%, positive control), or sterilised saline with carnitine at 25, 50, 100, 200, 300, 400, and 500 microg/egg. 2. In ovo carnitine treatment increased CWT, CWT%, glycogen in the liver and pectoral muscle, glycogen index and plasma IGF-1 of hatched chicks, and did not influence hatchability traits and hatching period. The glycogen index of hatched chicks of the in ovo carnitine treatments with values (500 > 400 = 300 > 200) was higher than that of the control and in ovo carnitine at 25, 50, and 100 microg/egg treatments. The nature of response to carnitine was cubic for CWT and CWT%, and linear for glycogen in the liver and pectoral muscle, glycogen index of hatched chicks when the negative control or positive control treatment was used as base line. 3. It was concluded that in ovo administration of carnitine at 25-500 microg/egg increased chick weight at hatch and IGF-1, and did not influence hatchability traits and hatching period of eggs. The linear relationship between in ovo administration of carnitine and glycogen status of hatched chicks indicated that increasing in ovo doses improved glycogen status of hatched chicks.

Effects of electrical field on hatchability performance of eggs from a layer-type breeder.

1. Eggs from a layer-type breeder flock (Baladi, King Saud University) between 50 and 63 weeks of age were used in three trials to study the effects of electrical field (EF) during incubation on albumen and yolk heights, incubation temperature, egg weight loss and hatchability traits. The effects of egg size and eggshell characteristics on hatchability traits of eggs incubated under EF were investigated. 2. Eggs were weighed and graded into three weight classes (small, medium, and large). The physical dimensions, eggshell characteristics, and conductance of eggs were examined. The incubator was divided into two compartments for the control and EF treatments. Two aluminium plates were fitted on the inside walls of the EF compartment, face to face, and connected to a step up electric transformer. Eggs were exposed constantly to the EF during the first 18 d of incubation at the level of 30 kV/m, 60 Hz. 3. Egg size influenced the physical dimensions and eggshell characteristics of eggs. Large eggs had higher egg weight, egg surface area, egg volume, eggshell conductance, and eggshell weight and lower yolk weight percentage than medium or small size eggs. Small eggs had lower egg length and higher egg density than large or medium size eggs. Large eggs had higher eggshell thickness than small size eggs. 4. EF incubation of eggs raised incubation temperature by 0.06 degrees C, and increased the percentage of egg weight loss, hatchability, and weight of hatching chicks and reduced the early embryo deaths, and length of incubation by approximately 9.8, 19.6, 1.7, 62.1 and 2.1%, respectively. 5. There was no significant difference between the two incubation treatments in the heights of albumen and yolk of incubated eggs, percentages of late embryo deaths, and pips with live and dead embryos. Hatchability traits were not significantly influenced by egg size. 6. It was concluded that EF incubation of eggs increased hatchability, chick-hatching weight, and reduced the length of incubation of Baladi eggs. Differences in the physical dimensions and eggshell characteristics of eggs did not influence hatchability traits of eggs under EF incubation.

Effect of electric field during incubation of eggs on the immune responses of hatched chickens.

The effects of electric field (EF) during incubation of eggs on the immunocompetence of chickens were investigated over a 42-day experimental period. Eggs from a meat-type breeder flock were incubated under EF of 30 kV/m, 60 Hz during the first 18 days of incubation as compared with the control incubation (C). Chickens from the two incubation treatments were fed ad libitum and their immune system were monitored. Measurements were made of body weight (BW), and lymphoid organs weight (thymus, spleen, and bursa of Fabricius (BOF)) of birds at 21 and 42 days of age. Immune systems of birds were tested for specific antibody responses to sheep red blood cell (SRBC) and Newcastle disease vaccine (NDV), in vivo T-lymphocyte proliferation responses to phytohemagglutinin (PHA), and in vitro to concanavalin A (Con-A). EF incubation of eggs did not significantly (P > 0.05) influence BW of bird, absolute weight of lymphoid organs and weight of thymus, and BOF as a percentage of BW of bird (% BW) at 21 and 42 days of age, humoral immune responses as measured by antibody responses to SRBC and NDV, and cell-mediated immune responses as measured by T-lymphocyte proliferation responses to PHA, and Con-A of birds when compared with those of the C treatment. EF incubation of eggs significantly (P < 0.05) increased spleen weight as a % BW at 21 and 42 days of age when compared with those incubated under the C treatment. Birds at 42 days of age had significantly (P < 0.01) higher BW, lymphoid organ weight, and weight of BOF as a % BW, and lower spleen weight as a % BW when compared with those of 21 days of age. It is concluded that the incubation of eggs under EF of 30 kV/m, 60 Hz increased spleen weight as a % BW, without altering cell-mediated and humoral immune responses and, consequently, immunocompetence of meat chickens during the rearing period of 42 days.

Incubation temperature and hemoglobin dielectric of chicken embryos incubated under the influence of electric field.

Eggs from a layer-type breeder flock (Baladi, King Saud University) between 61 and 63 weeks of age were used in 3 trials to study the effects of electric field (EF) during incubation on the internal temperature of incubation, and eggs and hemoglobin (Hb) dielectric of chicken embryos at 18 days of age. Dielectric relative permittivity (epsilon') and conductivity (sigma) of Hb were examined in the range of frequency from 20 to 100 kHz. The values of dielectric increment (Deltaepsilon') and the relaxation times (tau) of Hb molecules were calculated. The internal temperature of eggs was measured in empty (following the removal of egg contents) and fertilized eggs in trials 1 and 2, respectively. The level of the EF was 30 kV/m, 60 Hz. EF incubation of embryos influenced the temperature of incubation and electrical properties of Hb molecules and did not influence the temperature of incubation and internal environment of eggs when empty eggs were incubated. EF incubation of fertilized eggs significantly raised the temperature of incubation, egg air cell, and at the surface of the egg yolk by approximately 0.09, 0.60, and 0.61 degrees F, respectively and Hb epsilon', sigma, Deltaepsilon', and tau as a function of the range of frequency of 20 to 100 kHz when compared with their counterparts of the control group. It was concluded that the exposure of fertilized chicken eggs to EF of 30 kV/m, 60 Hz, during incubation altered dielectric properties of Hb and that probably affected cell to cell communication and created the right environment for enhancing the growing process and heat production of embryos consequently increasing the temperature of the internal environment of the egg, and incubation.

Effect of intensity of eggshell pigment and illuminated incubation on hatchability of brown eggs.

The effects of intensity of brown eggshell pigment (light (LBP), medium (MBP) and dark (DBP)) and light intensity during incubation (low and high, 900 to 1380 and 1430 to 2080 lux, respectively) on eggshell characteristics, embryonic growth, hatchability traits, chick hatching weight and hatching time were investigated using eggs from a meat-type breeder (Hybro) flock at 32, 36 and 41 weeks of age in three trials. With eggs of similar weights the intensity of brown pigment was not associated with eggshell weight and thickness, and did not influence embryo weight and egg weight loss during incubation. The shade of brown pigment of eggs laid by young hens influenced the percentage hatchability (HP) of eggs incubated under light. Illuminated incubation improved HP of LBP eggs (compared with MBP and DBP eggs) from 32- and 36-week-old hens, but had no significant effect on HP of eggs from 41-week-old hens. Light intensity during incubation did not influence egg weight loss. High intensity of light during incubation reduced HP and increased early death percentage (EDP) in the LBP and MBP groups, and did not influence HP and EDP in the DBP group. Brown eggshell pigment and intensity of light during incubation did not influence hatching time. It is concluded that the shade of brown pigment, intensity of light during incubation and age of the breeder hens influenced the hatchability performance of embryos from brown eggs. Light during incubation improved the hatchability of embryos in light brown eggs laid by young hens and the shade of brown pigment of eggs laid by older hens did not influence hatchability under illuminated incubation. High intensity of light during incubation reduced hatchability of light and medium brown eggs, but not the dark brown eggs.

Enhancement of chicken macrophage phagocytic function and nitrite production by dietary Spirulina platensis.

The effects of dietary Spirulina platensis on chicken macrophage phagocytic function and nitrite production were examined. Day old broiler (meat-type) chicks were randomly assigned to various pens of electrically heated wire batteries. Dietary treatment groups included a basal diet with no dietary Spirulina added, and three additional groups with 0.5, 1.0 and 2.0% dietary Spirulina. Feed and water were provided for ad libitum consumption from one day of age. Sephadex-elicited macrophages were harvested at 14, 35 and 42 days of age. Phagocytosis assay was performed by co-incubating sheep red blood cells (SRBC) with the adherent macrophage monolayers. For nitrite quantification, macrophage cultures from various dietary treatment groups were stimulated in the presence or absence of 1 microg/mL of Escherichia coli lipopolysaccharide. These culture supernatant fractions were then tested for nitrite levels using the Greiss reagent technique. All Spirulina dietary group macrophages exhibited an enhanced phagocytic activity in terms of overall phagocytic percentage (range = 28 to 39% versus 24 to 25% in the basal group) and the average number of SRBC per phagocytic macrophage (range = 2.2 to 3.6 versus 1.8 to 2.5 in the basal group). This increase was linear with each incremental increase of dietary Spirulina. While LPS-induced nitrite levels in macrophages from basal diet group ranged from 60 to 278 microM over the three developmental ages, these levels in all Spirulina dietary groups were significantly higher (0.5% group range = 198 to 457 microM; 1.0% group range = 161 to 359 microM and 2.0% group range = 204 to 420 microM. These data clearly show that Spirulina platensis feeding upregulates macrophage phagocytic as well as metabolic pathways leading to increased nitric oxide synthase activity. These findings therefore imply that Spirulina platensis may enhance the functions of mononuclear phagocytic system thereby increasing the disease resistance potential in chickens.

Duodenal calcium uptake, femur ash, and eggshell quality decline with age and increase following molt.

An experiment was conducted to test the hypothesis that the decline in eggshell quality over time during egg production, and its improvement after molting, paralleled the rate of calcium uptake by the duodenum of the laying hen. In vitro duodenal calcium uptake rate and femur ash (percentage of femur weight) were determined at 37, 45, 51, 58, 68, and 72 wk of age. Percentage shell and shell thickness (millimeters) were determined at 22, 29, 36, 44, 50, 57, and 71 wk of age. Molt was induced at 63 wk of age. Three commercial strains DeKalb XL-Link, ISA/Babcock B-300V, and Hy-Line W-36 were compared. There were no differences in duodenal calcium uptake rate among strains. There was a significant decline (P < .01) in duodenal calcium uptake from 408 pmol/mg tissue per min at 37 wk of age to 329 pmol/mg per min at 58 wk of age. Femur ash decreased (P < .01) from 50.8% at 37 wk of age to 47.6% at 58 wk of age. Percentage shell and shell thickness declined (P < .01) from 9.79% and .403 mm at 22 wk of age to 8.88% and .373 mm at 57 wk of age, respectively. After the induced molt, duodenal calcium uptake increased (P < .01) to 402 pmol/mg tissue per min, and percentage shell and shell thickness increased (P < .01) to 10.23% and .389 mm, respectively. Duodenal calcium uptake increased immediately postmolt, whereas femur ash did not increase until 72 wk of age (P < .01).

Responses of turkey poults to virginiamycin as influenced by litter condition and experimentally induced stunting syndrome.

Two experiments were conducted to evaluate the effect of virginiamycin (VM, 22 mg/kg of diet) on performance of uninfected (CON) turkey poults and those infected (INO) with stunting syndrome and reared on used woodshavings (Experiment 1) or on clean or used woodshavings (Experiment 2). Virginiamycin improved BW (P less than .001) and feed efficiency (FE) (P less than .05) from 1 to 29 days of age, irrespective of type of litter or disease condition. The increase in BW induced by VM, however, was greatest when poults were kept on used litter, resulting in significant (P less than .05) VM by litter interaction. Induced stunting syndrome depressed BW (P less than .01) to 29 days of age and impaired FE from 1 to 9 days of age (P less than .05) and from 5 to 9 days of age (P less than .01) in Experiments 1 and 2, respectively. Virginiamycin did not prevent early adverse effects of INO on BW and FE, but facilitated notable recovery of INO poults relative to INO poults not fed VM. Virginiamycin increased specific activities of maltase and sucrase of the jejunum of CON poults in Experiments 1 and 2; in Experiment 2, this VM effect was evident irrespective of type of litter. Maltase-specific activity and sucrase were reduced by INO (P less than or equal to .05 and P less than or equal to .01 in Experiments 1 and 2, respectively) and VM did not modify this effect. The maltase and sucrase data suggest that VM improved BW and FE of CON poults, in part, by helping to maintain digestive and absorptive functions of the small intestine during the early growth period, but, in the instance of INO poults, VM was not effective in this regard.

Posthatching changes in the immunoglobulin A concentration in the jejunum and bile of turkeys.

An experiment was conducted to document the age-related changes in IgA concentration in the small intestine of newly hatched turkey poults reared in floor pens and to determine whether infection with stunting syndrome (SS) affects age-related changes. Day-old turkey poults were dose per os with .5 mL of saline carrier (control) or with .5 mL of one of two dilutions (250- or 2.5 x 10(6)-fold) of a "crude" SS-causing inoculum. Inoculation with the 250-fold dilution depressed body weight gain (P less than .01) throughout the experiment and impaired feed efficiency (P less than .05) at 5 and 9 days of age as compared with the control group. After 9 days of age, all inoculated poults utilized feed more efficiently than did control poults (P less than .01). Stunting syndrome did not affect IgA concentrations in either bile or jejunum at any specific age. Age-related changes in IgA concentrations, however, were observed. Bile IgA decreased from 1 to 9 days of age, and then increased until 29 days of age. The IgA concentration in jejunal tissue increased linearly from 1 to 29 days of age (P less than .01), whether expressed as IgA concentration per gram of wet tissue or as percentage of total protein in jejunum. Age-related changes in IgA concentration in both bile and jejunum suggest that the secretory immune system associated with the digestive mucosa is not fully developed at the time of hatch.

Developmental patterns of selected characteristics of the gastrointestinal tract of young turkeys.

Developing embryos and hatchling poults were sampled (n = 4) at Days 22, 24, 26, and 28 of incubation and at 1, 2, 4, 6, and 8 days after hatching, and selected characteristics of the gastrointestinal tract (GIT) were measured. Body weight increased linearly up to day of hatching and also from 2 to 8 days posthatching. Residual yolk weight decreased rapidly starting on Day 26 of incubation and was nearly depleted by 4 days posthatching. Changes in weight of segments of the GIT nearly paralleled the increase in body weight until day of hatching. Thereafter, weights of the proventriculus, small intestine, and pancreas increased more rapidly than body weight until 6 days after hatching. At this time, change in weight of small intestine and pancreas seemed to parallel that of body weight, whereas proventriculus weight continued to increase more rapidly. Gizzard weight, as a percentage of body weight, increased until Day 4 posthatching and then remained relatively constant through 8 days. Specific activities (SA) of pancreatic amylase, lipase, and trypsin were low until after hatching. Subsequently, amylase SA increased nearly threefold by Day 6. Lipase SA remained nearly constant between Days 1 and 8, and trypsin SA increased only slightly. Total activities of pancreatic enzymes, however, increased substantially after hatching, mainly because of increased pancreas weight. Jejunal maltase SA was high at hatching but decreased markedly by Day 4. This decrease in SA resulted in a notable reduction in total maltase activity of the jejunum despite an increase in jejunum weight.