RESUMEN
1. An experiment was conducted to investigate the influence of dietary casein phosphopeptides and 25-hydroxycholecalciferol on the incidence of tibial dyschondroplasia (TD) in 14-d-old commercial broiler chickens. 2. Three hundred and twenty broiler chicks (one day old) were randomly allocated to one of 4 dietary treatments. A standard broiler diet was used as the control with the three experimental treatments receiving the control diet supplemented with 10 g casein phosphopeptide/kg, 14 g casein phosphopeptide/kg or 69 microg 25-hydroxycholecalciferol/kg. 3. Those birds fed the diets supplemented with 14g casein phosphopeptide/kg or 25-hydroxycholecalciferol had a lower incidence of TD than both the control and 10g casein phosphopeptide/kg treatments when assessed grossly. 4. The body weight of birds fed the 10 g casein phosphopeptide/kg diet or the 25-hydroxycholecalciferol diet was higher than birds fed the control diet. Although not significant, the body weight of birds fed the 14 g casein phosphopeptide/kg diet was also greater than the control birds. 5. The current experiment demonstrated that both casein phosphopeptide and 25-hydroxycholecalciferol can reduce the incidence of TD in the young broiler chicken. More research is required to explain the unexpected increase in body weight described above.
Asunto(s)
Calcifediol/uso terapéutico , Caseínas/uso terapéutico , Pollos/crecimiento & desarrollo , Osteocondrodisplasias/veterinaria , Fosfopéptidos/uso terapéutico , Enfermedades de las Aves de Corral/prevención & control , Alimentación Animal/análisis , Animales , Peso Corporal/efectos de los fármacos , Calcio/análisis , Relación Dosis-Respuesta a Droga , Femenino , Miembro Posterior/crecimiento & desarrollo , Masculino , Osteocondrodisplasias/prevención & control , Fósforo/análisisRESUMEN
1. Production-induced osteoporosis in caged laying hens is thought to represent a major constraint to continued genetic development. 2. The relationship between body weight, egg production, skeletal abnormalities characteristic of osteoporosis, femur calcium and bone histology was examined in a flock of ISA Brown layers from 16 to 68 weeks of age. 3. Experiment 2 examined a flock of Lohmann browns for skeletal abnormalities characteristic of osteoporosis at 45 weeks of age and the severity of abnormalities was then related to body weight and production between 18 and 45 weeks of age. 4. Average body weight declined in the ISA flock between 35 and 45 weeks of age, which correlated with a loss of skeletal calcium reserves (15% to 20%) and with the induction of osteoporosis. Between 42 and 68 weeks of age, birds were able to replenish femur calcium levels. 5. Birds in the Lohmann flock showing severe skeletal abnormalities at 45 weeks of age experienced weight loss between 27 and 31 weeks of age, which was associated with a decrease in egg production of 18%. After 35 weeks of age, egg production of these birds recovered to similar levels as unaffected or mildly affected birds. 6. It seems likely that better standardisation of the equilibrium between growth, skeletal reserves, food intake and egg production can reduce osteoporosis, as well as improving the productive potential of modern laying strains.
Asunto(s)
Huesos/fisiología , Calcio/análisis , Pollos/genética , Osteoporosis/veterinaria , Enfermedades de las Aves de Corral/genética , Factores de Edad , Animales , Densidad Ósea/genética , Densidad Ósea/fisiología , Huesos/química , Huesos/diagnóstico por imagen , Calcio/administración & dosificación , Pollos/anatomía & histología , Femenino , Vivienda para Animales , Osteoporosis/genética , Osteoporosis/fisiopatología , Oviposición/fisiología , Enfermedades de las Aves de Corral/fisiopatología , Radiografía , Índice de Severidad de la EnfermedadRESUMEN
The research described in this paper relates the changes in serum concentration of calcium, phosphorus, and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] to changes in tibial ash percentage and the incidence of endochondral ossification defects (EOD) in flocks of commercially reared broiler chickens at 14 d of age. Sequential studies of six Australian broiler flocks representing three major genetic lines were undertaken at weekly intervals from 1 to 28 d of age. Serum collected from birds was analyzed for total calcium, inorganic phosphorus, and 1,25(OH)2D3. Tibial ash percentage was also determined at weekly intervals, and the incidence of EOD was determined at 14 d of age by examining sagittal sections of the proximal tibiotarsus. The EOD observed in the 14-d-old broiler chickens were characterized by enlarged zones of proliferating chondrocytes, similar to that which occurs during calcium- or vitamin D-dependent rickets. Three flocks had a 50% incidence of EOD at 14 d of age and were classified as severely affected. The other three flocks had incidences ranging from 12 to 16% and were classified as mildly affected. Broiler flocks severely affected with EOD (50% incidence at Day 14) had lower (P < or = .05) concentrations of 1,25(OH)2D3 than flocks mildly affected (12 to 16% incidence). Tibial ash percentages were lower (P < or = .05) in the severely affected flocks between Days 14 to 28, and it is likely that a lower rate of ash accretion between Days 7 to 14 precedes the development of the EOD.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Calcitriol/sangre , Calcio/sangre , Pollos/sangre , Osteocondrodisplasias/veterinaria , Fósforo/sangre , Enfermedades de las Aves de Corral/sangre , Animales , Densidad Ósea , Incidencia , Osteocondrodisplasias/sangre , Osteocondrodisplasias/epidemiología , Enfermedades de las Aves de Corral/epidemiología , Tibia/fisiopatologíaRESUMEN
1. The plasma calcium and magnesium concentrations of sheep have been manipulated by feeding liquid diets with various calcium and magnesium concentrations. 2. When the magnesium status of the diet was low, both plasma calcium and magnesium concentrations declined, but the decline in calcium was much more rapid and extensive when the content of calcium in the diet was also low. This loss of calcium control in magnesium deficiency was attributed to end-organ resistance to parathyroid hormone. 3. Correlation between plasma and CSF calcium and magnesium concentrations indicated that convulsions occurred when CSF magnesium and plasma calcium concentrations declined. 4. The neurological mechanisms likely to be responsible for the induction of these convulsions are discussed and the factors precipitating convulsions in magnesium deficiency and epilepsy are compared.
Asunto(s)
Epilepsia/etiología , Deficiencia de Magnesio/fisiopatología , Convulsiones/etiología , Animales , Calcio/sangre , Calcio/líquido cefalorraquídeo , Dieta , Femenino , Magnesio/sangre , Magnesio/líquido cefalorraquídeo , OvinosRESUMEN
Sheep given a liquid diet low in calcium and magnesium by infusion directly into the abomasum developed concurrent hypocalcaemia and hypomagnesaemia, with plasma concentrations of calcium and magnesium decreasing to 2.0 and 0.4 mmol/l respectively. Treatment of these hypomagnesaemic sheep with 1,25 dihydroxyvitamin D3 (1,25(OH)2 D3) increased the plasma calcium, magnesium and phosphorus concentrations with plasma calcium increasing to 2.5 mmol/l and plasma magnesium to 0.6 mmol/l. Plasma magnesium increased despite a small but significant increase in the daily excretion of magnesium in the urine, and the amount of magnesium derived from either bone and/or intestine must have been greater than the amount lost in the urine. Since in other experiments we have demonstrated that plasma calcium remains within the normal range when a liquid diet adequate in magnesium but low in calcium is infused, these results imply that either synthesis of and/or end organ response to 1,25(OH2) D3 is impaired in magnesium deficient sheep.