RESUMEN
Vitamin D is an important immunomodulator that mediates its effect via a nuclear receptor. In this study, we analyzed 3 uncorrelated genetic markers (tag single nucleotide polymorphisms) in the vitamin D receptor gene for association with Marek's disease (MD) resistance. The database consisted of 400 commercial White Leghorn chickens that had been vaccinated with herpes turkey virus and challenged by intraperitoneal injection of the virulent MD virus RB1B. Viral titers in feather tips were determined at weekly intervals for 8 wk, mortality was recorded, and necropsy analyses preformed on all chickens. The 3 genotypes defined by 1 of the markers were associated with significant differences in the viral load (integration of the viral titer over time; P = 3 x 10(-4)). The effect was additive, with the 2 homozygotes differing by a factor of 2. The ranking of the genotypes by viral load, frequency of MD lesions, mortality, and bursal atrophy were consistent. There was no effect on the tissue distribution of MD lesions. The degree of MD resistance in the 9 genotypes defined by the 3 tag single nucleotide polymorphisms was proportional to the frequency of major histocompatibility complex class II-positive peripheral blood leukocytes that had been previously measured in uninfected chickens in a different database.
Asunto(s)
Enfermedad de Marek/genética , Enfermedades de las Aves de Corral/genética , Receptores de Calcitriol/genética , Animales , Pollos , ADN/genética , ADN/aislamiento & purificación , ADN Viral/genética , ADN Viral/aislamiento & purificación , Femenino , Marcadores Genéticos , Antígenos de Histocompatibilidad Clase II/análisis , Inmunidad Innata/genética , Mardivirus/genética , Mardivirus/inmunología , Enfermedad de Marek/inmunología , Polimorfismo de Nucleótido Simple , Enfermedades de las Aves de Corral/inmunología , Carga ViralRESUMEN
1. The effects of the endocannabinoid, anandamide, and its metabolically stable analogue, methanandamide, on induced tone were examined in sheep coronary artery rings in vitro. 2. In endothelium-intact rings precontracted to the thromboxane A(2) mimetic, U46619, anandamide (0.01 - 30 microM) induced slowly developing concentration-dependent relaxations (pEC(50) [negative log of EC(50)]=6.1+/-0.1; R(max) [maximum response]=81+/-4%). Endothelium denudation caused a 10 fold rightward shift of the anandamide concentration-relaxation curve without modifying R(max). Methanandamide was without effect on U46619-induced tone. 3. The anandamide-induced relaxation was unaffected by the cannabinoid receptor antagonist, SR 141716A (3 microM), the vanilloid receptor antagonist, capsazepine (3 and 10 microM) or the nitric oxide synthase inhibitor, L-NAME (100 microM). 4. The cyclo-oxygenase inhibitor, indomethacin (3 and 10 microM) and the anandamide amidohydrolase inhibitor, PMSF (70 and 200 microM), markedly attenuated the anandamide response. The anandamide transport inhibitor, AM 404 (10 and 30 microM), shifted the anandamide concentration-response curve to the right. 5. Precontraction of endothelium-intact rings with 25 mM KCl attenuated the anandamide-induced relaxations (R(max)=7+/-7%), as did K(+) channel blockade with tetraethylammonium (TEA; 3 microM) or iberiotoxin (100 nM). Blockade of small conductance, Ca(2+)-activated K(+) channels, delayed rectifier K(+) channels, K(ATP) channels or inward rectifier K(+) channels was without effect. 6. These data suggest that the relaxant effects of anandamide in sheep coronary arteries are mediated in part via the endothelium and result from the cellular uptake and conversion of anandamide to a vasodilatory prostanoid. This, in turn, causes vasorelaxation, in part, by opening potassium channels.
Asunto(s)
Ácidos Araquidónicos/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Capsaicina/análogos & derivados , Vasos Coronarios/efectos de los fármacos , Vasodilatación/efectos de los fármacos , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacología , 4-Aminopiridina/farmacología , Animales , Apamina/farmacología , Ácido Araquidónico/metabolismo , Bario/farmacología , Moduladores de Receptores de Cannabinoides , Cannabinoides/farmacología , Capsaicina/farmacología , Vasos Coronarios/fisiología , Inhibidores Enzimáticos del Citocromo P-450 , Relación Dosis-Respuesta a Droga , Endocannabinoides , Endotelio Vascular/fisiología , Inhibidores Enzimáticos/farmacología , Ácidos Grasos Insaturados/farmacología , Gliburida/farmacología , Técnicas In Vitro , Indometacina/farmacología , Miconazol/farmacología , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Péptidos/farmacología , Fluoruro de Fenilmetilsulfonilo/farmacología , Piperidinas/farmacología , Alcamidas Poliinsaturadas , Potasio/farmacología , Bloqueadores de los Canales de Potasio , Canales de Potasio/fisiología , Pirazoles/farmacología , Receptores de Droga/antagonistas & inhibidores , Rimonabant , Ovinos , Tetraetilamonio/farmacología , Vasoconstrictores/farmacologíaRESUMEN
We compared the abilities of diltiazem and siratiazem to protect the heart against coronary artery occlusion and reperfusion-induced arrhythmias in anaesthetised rats and assessed their effects on cardiac action potentials (APs) recorded in paced sheep Purkinje fibres. Both drugs in the concentration range of 0.5-4 mg kg-1 reduced the number of ventricular ectopic beats and the percentage of incidence of ventricular tachycardia (VT) that occurred during the first 7 min after coronary artery occlusion. The incidence of ventricular fibrillation (VF) on reperfusion was significantly reduced by siratiazem at a concentration of 2 mg kg-1 only. These antiarrhythmic effects were not accompanied by a reduction in mortality but were associated with a marked and sustained bradycardia and a decrease in mean arterial blood pressure (MAP). In sheep Purkinje fibres, diltiazem and siratiazem (10(-6)-10(-5) M) caused concentration-dependent reductions in AP duration measured at both 50 and 90% of repolarisation (APD50 and APD90), in the maximum rate of depolarisation of phase 0 and in AP amplitude (APA). Resting membrane potential (RMP) was not modified by either drug. The antiarrhythmic effects of both diltiazem and siratiazem may be due in part to direct electrophysiologic effects on cardiac tissue to block sodium and calcium channels and in part to an antiischaemic effect associated with bradycardia and vasodepression.
Asunto(s)
Antiarrítmicos/farmacología , Enfermedad Coronaria/prevención & control , Diltiazem/análogos & derivados , Diltiazem/farmacología , Animales , Estimulación Eléctrica , Electrofisiología , Corazón/fisiología , Hemodinámica/efectos de los fármacos , Masculino , Ramos Subendocárdicos/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/prevención & control , OvinosRESUMEN
1. The electrophysiological effects of a series of drugs with Class I antiarrhythmic activity were examined in sheep Purkinje fibres, superfused in vitro with either a normal or hypoxic, hyperkalaemic and acidotic physiological salt solution (PSS). 2. In normal sheep Purkinje fibres, lignocaine, disopyramide, nicainoprol and propranolol all significantly reduced action potential height and the maximum rate of depolarization of phase zero (MRD) and abbreviated the action potential, without modifying resting membrane potential (RMP). 3. Verapamil at the highest concentration studied, 8 microM, significantly reduced MRD with an associated slight membrane depolarization and abbreviated action potential duration measured at 50% repolarization (APD50). 4. Superfusion of sheep Purkinje fibres with a hypoxic, hyperkalaemic and acidotic PSS resulted in marked reductions in resting membrane potential, upstroke and duration of the action potential. 5. In the presence of modified PSS, lignocaine, propranolol and verapamil all reduced MRD to a greater extent than in normal PSS. The effects of nicainoprol on MRD were not affected whereas those of disopyramide were significantly attenuated. 6. Under simulated ischaemic conditions, lignocaine, propranolol and nicainoprol did not produce a concentration-dependent reduction in action potential duration whereas disopyramide and verapamil, respectively, prolonged and abbreviated both APD50 and APD90. 7. The Na+ channel blocking actions of the different subtypes of Class I antiarrhythmic agents studied, as well as their effects on action potential duration, were modified differently by simulated ischaemia.
Asunto(s)
Acidosis/fisiopatología , Antiarrítmicos/farmacología , Electrocardiografía/efectos de los fármacos , Corazón/fisiopatología , Hiperpotasemia/fisiopatología , Hipoxia/fisiopatología , Potenciales de Acción/efectos de los fármacos , Animales , Disopiramida/farmacología , Electrofisiología , Técnicas In Vitro , Lidocaína/farmacología , Propanolaminas/farmacología , Propranolol/farmacología , Ramos Subendocárdicos/efectos de los fármacos , Ovinos , Verapamilo/farmacologíaRESUMEN
The aim of this study was to determine the electrophysiological effects of a combination of factors that are of importance during myocardial ischaemia, i.e., acidosis, lactate, and lysophosphatidylcholine, in ventricular myocytes. Intracellular microelectrode techniques were used to record action potential and ionic currents in ventricular myocytes before, during, and after a 30 min exposure to a salt solution that was acidotic (pH 6.8), and contained lactate (10 mM) and lysophosphatidylcholine (5 microM). Single ventricular myocytes were dissociated enzymatically from guinea pig hearts, and perfused with either normal or modified physiological salt solution. Combined acidosis, lactate, and lysophosphatidylcholine resulted in a reduction in the resting membrane potential and maximum rate of depolarisation of phase 0, and flattening of the plateau but prolongation of the action potential duration at 90% repolarisation. Automatic activity was also induced in about one-third of the cells studied. Under voltage-clamp conditions, this combination of factors reduced the peak inward calcium current, on repolarisation after a depolarising step, reduced the steady-state outward current, and reduced the delayed rectifier current, measured as the tail current at the end of a depolarising clamp step. In some cells, a transient inward current was induced by the modified salt solution. It is concluded that the characteristic alterations in action potential characteristics induced by a combination of acidosis, lactate, and lysophosphatidylcholine are likely to result from reductions in the inward Ca current and the background and delayed rectifier K current.
Asunto(s)
Acidosis/fisiopatología , Canales Iónicos/efectos de los fármacos , Lactatos/farmacología , Lisofosfatidilcolinas/farmacología , Miocardio/metabolismo , Potenciales de Acción/efectos de los fármacos , Animales , Cobayas , Corazón/efectos de los fármacos , Corazón/fisiología , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Canales Iónicos/metabolismo , Masculino , Isquemia Miocárdica/metabolismo , Canales de Potasio/efectos de los fármacosRESUMEN
1. The effects of buprenorphine, given intravenously, on the incidence and severity of early acute coronary artery occlusion-induced arrhythmias were examined in anaesthetised rats. The electrophysiological effects of buprenorphine were also examined in sheep Purkinje fibres and rat papillary muscles, superfused in vitro with either a normal or a hypoxic, hyperkalaemic and acidotic physiological salt solution (PSS). 2. In anaesthetised rats subjected to acute coronary artery occlusion, pretreatment with buprenorphine (1 mg kg-1 i.v.) markedly reduced the incidence of ventricular extra-systoles during the initial 30 min post-occlusion period. The incidence of ventricular fibrillation (VF) was also significantly reduced from 56% to 10%. 3. At the antiarrhythmic dose (1 mg kg -1), buprenorphine also attenuated the sudden fall in systemic arterial blood pressure induced by acute coronary artery ligation. 4. In normal sheep Purkinje fibres and rat papillary muscles, buprenorphine (10(-6)-10(-5) M) significantly reduced the action potential height and maximum rate of depolarisation of phase zero (MRD) and prolonged the duration of the action potential. 5. Superfusion of sheep Purkinje fibres and rat papillary muscles with a hypoxic, hyperkalaemic and acidotic PSS resulted in marked reductions in resting membrane potential, upstroke and duration of the action potential. 6. In the presence of the modified compared with normal PSS, buprenorphine reduced the action potential height and MRD of both sheep Purkinje fibres and rat papillary muscles to a greater extent, although its ability to prolong the action potential duration was attenuated. 7. The antiarrhythmic effects of buprenorphine observed in vivo may be explained by its direct cardiac electrophysiological effects. Buprenorphine might be useful in relieving pain and in reducing the severity of arrhythmias in the early stages of acute myocardial infarction.
Asunto(s)
Antiarrítmicos , Buprenorfina/farmacología , Corazón/efectos de los fármacos , Anestesia , Animales , Presión Sanguínea/efectos de los fármacos , Enfermedad Coronaria/fisiopatología , Vasos Coronarios/efectos de los fármacos , Electrofisiología , Técnicas In Vitro , Masculino , Músculos Papilares/efectos de los fármacos , Ratas , Ratas Endogámicas , Ovinos , Factores de TiempoRESUMEN
1. The electrophysiological effects of adenosine and adenosine triphosphate (ATP) were examined in sheep Purkinje fibres, superfused in vitro with either a normal or a hypoxic, hyperkalaemic and acidotic physiological salt solution (PSS). The ability of adenosine to modify the effects of noradrenaline on action potential characteristics was also investigated. 2. The only statistically significant effects of adenosine (10(-6)-10(4) M) and of ATP (10(-6)-10(-4) M) on normal action potential characteristics were a slight dose-dependent shortening of the action potential by adenosine and a depolarization by ATP, 10(-4) M. 3. Superfusion with a hypoxic, hyperkalaemic and acidotic PSS caused marked reductions in resting membrane potential, upstroke and duration of the action potential. 4. Both adenosine and ATP attenuated the reduction in the rate of rise of the upstroke and the amplitude of the action potential caused by the modified PSS. 5. Adenosine did not alter the noradrenaline-induced effects on automaticity or on action potentials of normal or depressed Purkinje fibres. 6. Adenosine and ATP had electrophysiological effects on Purkinje fibres, exposed to conditions in vitro that mimic mild myocardial ischaemia, that were different from those observed on normally polarized fibres.
Asunto(s)
Adenosina Trifosfato/farmacología , Adenosina/farmacología , Sistema de Conducción Cardíaco/fisiología , Ramos Subendocárdicos/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Electrofisiología , Hipoxia/fisiopatología , Técnicas In Vitro , Isquemia/fisiopatología , Norepinefrina/farmacología , Ramos Subendocárdicos/efectos de los fármacos , OvinosRESUMEN
The aim of this study was to examine the electrophysiological effects of isoprenaline, phenylephrine, and noradrenaline on sheep Purkinje fibers in vitro, superfused either with a normal or with a modified physiological salt solution (PSS) designed to mimic some of the conditions occurring during mild myocardial ischemia (hyperkalemia, hypoxia, and acidosis). Intracellular microelectrode recording techniques were used to record resting and action potentials. Noradrenaline (10(-7) to 10(-5) M) and phenylephrine (10(-7) to 10(-5) M) prolonged the action potential of normal fibers in a concentration-dependent manner, the effect of phenylephrine being greater than that of noradrenaline. The only effect of isoprenaline (10(-7) to 10(-5) M) was a slight hyperpolarization. The modified PSS caused marked reductions in resting membrane potential, upstroke, and duration of the action potential. On these depressed fibers isoprenaline, noradrenaline, and phenylephrine all prolonged the action potential, and in the case of noradrenaline the duration of the abbreviated action potential was restored beyond control. This effect of noradrenaline and isoprenaline was more marked under ischemic than normal conditions, whereas the opposite was true of phenylephrine. In the presence of effective alpha- or beta-adrenoceptor blockade, the noradrenaline-induced prolongation of the "ischemia"-abbreviated action potential was attenuated. In some of the preparations exposed to simulated ischemia, noradrenaline caused inexcitability. In conclusion, isoprenaline, phenylephrine, and noradrenaline exhibited different electrophysiological effects on mildly "ischemic" sheep Purkinje fibers compared to their effects on normal fibers.
Asunto(s)
Enfermedad Coronaria/fisiopatología , Sistema de Conducción Cardíaco/efectos de los fármacos , Isoproterenol/farmacología , Norepinefrina/farmacología , Fenilefrina/farmacología , Ramos Subendocárdicos/efectos de los fármacos , Acidosis/fisiopatología , Potenciales de Acción/efectos de los fármacos , Antagonistas Adrenérgicos alfa/farmacología , Antagonistas Adrenérgicos beta/farmacología , Animales , Electrofisiología , Hiperpotasemia/fisiopatología , Hipoxia/fisiopatología , Técnicas In Vitro , Potenciales de la Membrana/efectos de los fármacos , OvinosRESUMEN
Level of damage caused by freezing and thawing to four spermatozoal organelles (individual mitochondrion, midpiece, nucleus, and perforatorium) and the relationships of the integrity of these organelles in fresh and frozen-thawed semen with fertility were examined. Semen sample from 10th generation males of a line of chickens selected for increased duration of fertility of frozen-thawed semen and the corresponding randombred control line were used. In both the selected and control lines, the freeze-thaw process caused significant (P less than .05) detrimental damage to the ultrastructure of the mitochondria, midpiece, and perforatorium but not to the nucleus. Types of damage were identical in both lines. Granulated nuclei were observed in both frozen-thawed and freshly ejaculated spermatozoa and were referred to as a nuclear defect. This nuclear defect was associated with reduced fertility, the effect being more severe with frozen-thawed semen. Where the incidence of the nuclear defect was greater than 2% in frozen-thawed semen, fertility was found to be very low or nil regardless of the degree of structural integrity of the mitochondria, midpiece and perforatorium. Highly significant (P less than .01) positive correlation coefficients were observed for percentage fertility 2 to 8 days postinsemination and duration of fertility in days with percentages of normal mitochondria (.80 and .92), midpiece (.79 and .87), nucleus (.86 and .94), and perforatorium (.84 and .97) for fresh semen. With frozen-thawed semen, the positive correlation coefficients were significant (P less than .05) for midpiece (.64 and .69) and nucleus (.63 and .71) and nonsignificant for mitochondria (.52 and .50) and perforatium (.20 and .30).(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Pollos/fisiología , Fertilidad , Espermatozoides/ultraestructura , Animales , Congelación , Masculino , Preservación de Semen/veterinariaRESUMEN
Ejaculate volume, sperm concentration, and sperm number per ejaculate were measured six times from 8 to 15 months of age, and testes and body weight at 15 months of age, on Generation 9 males of a line of broiler breeders selected for fertility of frozen-thawed semen and those of a randombred control line. Sperm quality (percent normal, percent abnormal, and percent dead sperm) was determined on Generation 10 males at 11 months of age. Selection decreased (P less than .01) ejaculate volume and sperm number per ejaculate. The control line had 4.9% more abnormal (P less than .05) sperm than the selected line. The differences between the lines for sperm concentration, testes and body weights, and percent dead sperm were not significant (P greater than .05). The correlation coefficients of fertility of frozen-thawed semen with percent abnormal and percent dead sperm were negative but were positive with percent normal sperm. The heritability and repeatability estimates of ejaculate volume, sperm concentration, and sperm number per ejaculate ranged from .34 to .73 and .33 to .51, respectively.
Asunto(s)
Fertilidad , Semen/fisiología , Espermatozoides/fisiología , Animales , Peso Corporal , Pollos , Congelación , Masculino , Tamaño de los Órganos , Recuento de Espermatozoides , Testículo/anatomía & histología , Conservación de TejidoRESUMEN
Studies were conducted using 68 males from the seventh generation of a line of meat-type breeder chickens selected for increased duration of fertility of frozen-thawed semen and 69 males of the randomly selected control line. These chickens were used to determine the presence or absence of differences between the selected and control lines with respect to fertility and spermatozoal motility when the semen was subjected to the following preinsemination treatments: 1) frozen in a diluent containing 13.6% glycerol; 2) frozen in a diluent containing 1.7% glycerol; 3) fresh undiluted; 4) fresh diluted; 5) diluted and stored for 24 hr; and 6) diluted and stored for 48 hr. Semen from each male was inseminated into 4 to 6 White Leghorn tester hens per experiment. The effects of genotype (line) by preinsemination semen treatment interaction on fertility and spermatozoal motility were also examined. When semen was frozen (Treatments 1 and 2), the selected line had significantly (P less than .01) higher duration of fertility, percent fertility for 7 days postinsemination, and percent fertility for the duration of fertility and spermatozoal motility than the control line. For fresh semen (Treatments 3 and 4), the selected line had significantly (P less than .01) higher fertility estimates and spermatozoal motility than the control line except for percent fertility for the duration of fertility (P greater than .05) of undiluted semen. For stored semen (Treatments 5 and 6), the selected line only had significantly (P less than .05) higher duration of fertility after 24 hr storage and percent fertility for the duration of fertility after 48 hr storage than the control line.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Pollos/genética , Fertilidad , Preservación de Semen/veterinaria , Semen/fisiología , Animales , Femenino , Congelación , Inseminación Artificial/veterinaria , Masculino , Selección Genética , Motilidad EspermáticaRESUMEN
The seminal plasma from individual ejaculates of 13 males of a line of chickens selected for increased duration of fertility of frozen-thawed semen for 7 generations and 12 males of the control line were analyzed for proteins. The mean +/- SE total seminal plasma protein of the selected and control lines were 8.74 +/- .55 micrograms and 7.52 +/- .92 micrograms/microliter seminal plasma (P greater than .05). Crossed immunoelectrophoretic analysis of the seminal plasma generated, in general, 11 precipitant peaks in both lines. The protein corresponding to peak 11 of the electrophoretic pattern was significantly (P less than .01) higher in the selected line than in the control line, the mean +/- SE being 1.80 +/- .21 and .85 +/- .19 micrograms/microliter seminal plasma.
Asunto(s)
Pollos/genética , Fertilidad , Proteínas de Secreción Prostática , Proteínas/análisis , Preservación de Semen/veterinaria , Semen/fisiología , Animales , Congelación , Inmunoelectroforesis Bidimensional , Masculino , Semen/análisis , Proteínas de Plasma SeminalRESUMEN
Broiler-type male turkeys housed in individual cages were compared with those housed in litter floor pens with respect to fertility, semen volume, concentration of spermatozoa, body weight, foot abnormality, and mortality. The effect of short-term storage of semen on fertility was also examined. There was no significant difference (P greater than .05) between the fertilities of the males in cages and those on floor when semen was diluted and inseminated fresh (92 vs. 88%) or diluted and stored for 6 hr at 15 (79 vs. 84%) or 3 C (77 vs. 85%). The males in cages produced as much semen as those on floor and with similar concentrations of spermatozoa. Those in cages had significantly (P less than 01) reduced body weight, higher incidence of foot abnormality, and higher percent mortality. Storage of semen for 6 hr reduced fertility.
Asunto(s)
Fertilidad , Vivienda para Animales , Semen/metabolismo , Pavos/fisiología , Animales , Peso Corporal , Pisos y Cubiertas de Piso , Masculino , Mortalidad , Semen/fisiología , Preservación de Semen/veterinaria , Pavos/metabolismoRESUMEN
The response to eight generations of selection for duration of fertility of frozen-thawed chicken semen, the correlated responses of other fertility parameters of frozen-thawed semen and the fertility of fresh semen, and the heritabilities of frozen-thawed and fresh semen were studied. The selected and control lines were derived from a base meat-type control male population developed at Peel's Poultry Farm Ltd., Port Perry, Ontario. Selection has improved duration of fertility of frozen-thawed semen significantly (P less than .01) with the mean increasing from 1 day in Generation 1 to 5 days in Generation 8 and an average improvement per generation of .29 day since Generation 3. There were significant (P less than .01) correlated increases in percent fertility for 2 to 8 days postinsemination and percent fertility for the duration of fertility of frozen-thawed semen as well as the fertility of fresh semen. Percent hatchability of fertile eggs of frozen-thawed semen did not change. In Generation 8, means and standard errors of fertility parameters of frozen-thawed semen in the selected and control lines, respectively, were: 38.54 +/- 1.39 and 25.58 +/- 1.77 for percent fertility for 2 to 8 days postinsemination, 47.73 +/- 3.54 and 32.02 +/- 2.17 for percent fertility for the duration of fertility, and 78.21 +/- 1.56 and 79.27 +/- 2.53 for percent hatchability of fertile eggs. For fertility of fresh semen, means and standard errors were: 12.69 +/- .20 and 11.54 +/- .42 for duration of fertility, 82.91 +/- 1.45 and 75.71 +/- 2.83 for percent fertility for 2 to 8 days postinsemination, and 71.89 +/- 1.25 and 69.22 +/- 2.06 for percent fertility for the duration of fertility. The means of the heritability estimates of the fertility of frozen-thawed and fresh semen, respectively, ranged from .01 to .31 and -.01 to .21. The realized heritability of duration of fertility of frozen-thawed semen, based on five generations, was .17 +/- .05. The phenotypic correlations of duration of fertility of frozen-thawed semen with percent fertility for 2 to 8 days postinsemination and percent fertility for the duration of fertility of frozen-thawed semen were high and positive and correlations between fertility of frozen-thawed and fresh semen were low but positive.
Asunto(s)
Pollos/genética , Fertilidad , Preservación de Semen/veterinaria , Semen/fisiología , Animales , Pollos/fisiología , Masculino , Selección GenéticaRESUMEN
The uptake of glycerol, alpha-aminoisobutyric acid and 2-deoxy-D-glucose by fowl spermatozoa was each measured in two trials using seventh generation males of a line selected for duration of fertility of frozen-thawed semen and those of a randomly selected control line. The selected line had significantly (P< 0.01) higher fertility of frozen-thawed and fresh semen than the control line. The association between glycerol level in spermatozoa before freezing and the fertility of frozen-thawed semen was examined. Significantly greater amounts (CPM/10(9) cells) of glycerol, alpha-aminoisobutyric acid and 2-deoxy-D-glucose were taken up by the spermatozoa of the selected line than those of the control line at 15, 30 and 60 min of incubation. Rank correlations between the fertility of frozen-thawed semen and glycerol levels were generally positive but low in magnitudes.
RESUMEN
The relationship of the reproductive performance and semen characteristics of commerical broiler parent males with their body weight at 6, 8, 10, and 12 weeks of age, keel length, shank length, breast angle at 8 weeks of age, and packed erythrocyte volume at 6 and 8 weeks of age were examined. Phenotype correlations of juvenile traits with subsequent reproductive traits were generally of low magnitude, except for the significant positive correlations of 6- and 8-week body weight with fertility. Positive correlations existed between fertility and semen quality traits which were significant in some cases. Six-week body weight and spermatozoal motility appeared to be the most useful traits in predicting a male's fertility.
Asunto(s)
Pollos/genética , Ingeniería Genética/veterinaria , Inseminación Artificial/veterinaria , Animales , Peso Corporal , Femenino , Fertilidad , Hematócrito , Masculino , Fenotipo , Semen , Motilidad EspermáticaRESUMEN
Studies were conducted to evaluate the reproductive capacity of male broiler breeders used for artificial insemination over an extended period and mated to females of six strains. Biweekly determinations were made of semen volume, semen concentration, and spermatozoal motility for each of the 47 males caged individually from their 39th to 63rd week of age. The percent fertility, duration of fertility, and percent hatchability were determined at five-week intervals (periods) using three young and three force-molted broiler female strains. With young female strains, the mean percent fertility for a 7-day collection of eggs following a single insemination (1 to 7 days) ranged from 95.7 to 81.1 over six consecutive periods. The mean duration of fertility (days) and the mean percent hatchability of fertile eggs was 13.3 and 13.0, and 92.5 and 84.9 respectively, for the first two periods. With force-molted hens, the mean percent fertility (1 to 7 days) ranged between 97.2 and 86.0 over the first three periods, and the mean duration of fertility and the mean percent hatchability was 13.2 and 12.8, and 91.5 and 84.1, respectively, for the first two periods. Fertility of eggs collected for 10 days following a single insemination was slightly but consistently lower than fertility over 7 days for both female groups. Significant differences among males and between periods existed for each semen trait. The effects of male, young female strain and period on fertility and duration of fertility were significant. Hatchability was significantly affected by period only. No male by female strain interaction existed for percent fertility or hatchability. A significant male by period interaction existed for percent fertility, semen volume and concentration. The results obtained are considered to support the feasibility of maintaining broiler breeders in cages and the use of artificial insemination (AI) to produce broiler hatching eggs.