RESUMEN
1. Nuclear magnetic resonance imaging (MRI) was used to assess the advantages of the technique in determining the size (volume) and shape of the Pectoralis muscle (Pectoralis major and minor) in broiler chickens, non-invasively and in vivo. 2. The imaging was performed using a Spectroscopy Imaging System 2.0 Tesla/31 cm bore imaging spectrometer. Three-dimensional reconstruction of transverse images was used to estimate the size of the Pectoralis muscle of chickens ranging in body weight from 362 to 1643 g. 3. Regression analysis resulted in R2 values of 0.92 and 0.99 for the relationship between Pectoralis muscle weight, body weight and muscle volume, respectively. 4. It is concluded that MRI and 3-dimensional image reconstruction may be used to estimate the Pectoralis muscle size and shape. This may be readily extended to monitor the influence of various factors on the growth and development of specific organs and tissues in the body.
Asunto(s)
Pollos/anatomía & histología , Músculo Esquelético/anatomía & histología , Animales , Peso Corporal , Procesamiento de Imagen Asistido por Computador , Espectroscopía de Resonancia Magnética/métodos , Masculino , Tamaño de los Órganos , Análisis de RegresiónRESUMEN
Three experiments were conducted with cage-reared broilers to 21 d following nutrient restriction from 6 to 12 d age. In Experiment 1, birds were full-fed from 6 to 11 or given 50% of ad libitum intake on a daily basis, or 100% of ad libitum intake on a daily basis when the diet was diluted 50% with oat hulls. Birds were not able to fully recover body weight depression by 21 d, although birds previously restricted, by whatever method, were more efficient (P < 0.01) in overall energy intake:body weight gain. Prior feed restriction had no effect on ability to metabolize diet energy (P > 0.05), although these birds did exhibit increased nitrogen retention compared to birds full-fed from 6 to 11 d. In a second experiment, birds were fed diets with 1.25, 1.38, 1.51, 1.63, 1.76, or 1.88% lysine in the realimentation diet from 12 to 21 d. Lysine level had no effect on growth rate or feed efficiency (P > 0.05) for full-fed birds; however there was a linear (P < 0.05) decline in growth rate from 12 to 21 d in response to extra dietary lysine for the birds previously feed restricted from 6 to 12 d. In a third experiment, birds were fed diets varying in energy (3,000 to 3,300 kcal/kg) or protein (22 to 29% CP) from 12 to 21 d following ad libitum vs 50% feed restriction from 6 to 11 d age. Protein level of the diet had little effect on performance traits to 21 d, although there was an indication of improved growth in response to the higher energy concentration. Birds full-fed from 6 to 11 d showed increased liver size at 21 d when fed more protein, although the converse was true for the restricted birds (P < 0.05). The growth response to diet energy was associated with increased carcass fatness. In general, there does not seem to be any advantage to manipulating diet formulation during realimentation of birds previously nutrient-restricted.
Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Pollos/crecimiento & desarrollo , Pollos/fisiología , Dieta/veterinaria , Ingestión de Energía/fisiología , Metabolismo Energético/fisiología , Abdomen , Tejido Adiposo/anatomía & histología , Animales , Pollos/metabolismo , Dieta/normas , Proteínas en la Dieta/farmacología , Proteínas en la Dieta/normas , Ingestión de Energía/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Lisina/farmacología , Lisina/normas , Masculino , Nitrógeno/metabolismo , Distribución Aleatoria , Aumento de Peso/fisiología , Pérdida de Peso/fisiologíaRESUMEN
Two experiments were conducted with 6- to 10-wk-old turkeys. In Experiment 1, 6-wk-old turkeys were fed diets varying in level of fat (4.4 to 10%) or fiber (2.5 to 9.0%). The diets also contained extra copper as copper sulfate at either 0.1 or 0.2% of the diet. At 8 wk of age, 15 replicate birds were housed in individual cages and all excreta was collected. Excreta was separated as being "regular" or "cecal" in origin based on appearance. At 10 wk of age, 10 birds per treatment were killed and cecal contents removed under anaerobic conditions. Cecal contents were assayed for various nutrients and viscosity was measured. In a second comparable study, turkeys were fed animal-vegetable fat or regular or rancid canola oil (60.25 vs 120.24 ng/g malonaldehyde, respectively). In Experiment 1, feeding copper sulfate had the most noticeable effect on various cecal parameters. There was an increase (P < 0.01) in dry matter cecal droppings produced and the cecal contents were of increased viscosity (P < 0.05). Copper had no effect on pH or microbial colony count of the cecal contents. Feeding copper resulted in a significant increase in the high molecular weight (> 300,000) fraction of cecal contents and this fraction was of higher viscosity. Feeding copper sulfate resulted in a dramatic increase in copper content of cecal contents (280 to 11,848 ppm), although the copper content of regular excreta was also increased (17 to 1,008 ppm). The various levels of fiber and fat generally had no effect on cecal parameters. Feeding rancid canola oil did result in increased viscosity of cecal contents, compared to the situation seen with fresh canola oil. Fat rancidity per se, however, failed to influence other parameters such as total mass of cecal material produced and composition of cecal material. Feeding copper sulfate or rancid fat will increase the viscosity of cecal material, which may contribute to litter management problems.
Asunto(s)
Ciego/fisiología , Sulfato de Cobre/farmacología , Grasas de la Dieta/farmacología , Fibras de la Dieta/farmacología , Ácidos Grasos Monoinsaturados/farmacología , Ácidos Grasos Monoinsaturados/normas , Pavos/fisiología , Animales , Peso Corporal/fisiología , Ciego/química , Ciego/microbiología , Relación Dosis-Respuesta a Droga , Concentración de Iones de Hidrógeno , Masculino , Peso Molecular , Distribución Aleatoria , Aceite de Brassica napus , Pavos/crecimiento & desarrollo , Aumento de Peso/fisiologíaRESUMEN
Two experiments were conducted to determine the physical, chemical, and microbial properties of turkey cecal droppings and relate them to intake of common dietary components, namely fat, fiber, and the anticoccidial, monensin. Experiment 1 involved collection and analysis of physical and chemical properties of cecal and regular droppings from commercial turkey flocks. Experiment 2 tested the effect of dietary fat, fiber, and monensin on growth performance and cecal activity in male turkeys. Compared to regular excreta, cecal droppings analyzed in Experiment 1 were higher in viscosity and fat content, and lower in dry matter, nitrogen, and fiber content (P < 0.05). High dietary fiber and fat significantly (P < 0.05) improved growth performance in Experiment 2. Prolonged feeding of monensin significantly (P < 0.05) reduced cecal evacuation. Results of chemical composition showed that higher dietary fat and fiber significantly (P < 0.01) reduced the fat percentage of cecal contents, whereas prolonged feeding of monensin increased the fat in both cecal contents and droppings. There was no significant effect of any of the treatments on pH, viscosity, and microbial counts of cecal contents. There is the need to identify and characterize the compound responsible for the high viscosity of cecal droppings.
Asunto(s)
Ciego/efectos de los fármacos , Coccidiostáticos/farmacología , Dieta/veterinaria , Grasas de la Dieta/farmacología , Fibras de la Dieta/farmacología , Monensina/farmacología , Pavos/fisiología , Animales , Peso Corporal/efectos de los fármacos , Peso Corporal/fisiología , Ciego/metabolismo , Ciego/fisiología , Coccidiostáticos/análisis , Grasas de la Dieta/análisis , Fibras de la Dieta/análisis , Heces/química , Heces/microbiología , Concentración de Iones de Hidrógeno , Lípidos/análisis , Masculino , Monensina/análisis , Nitrógeno/análisis , Distribución Aleatoria , Pavos/crecimiento & desarrollo , Viscosidad , Aumento de Peso/efectos de los fármacos , Aumento de Peso/fisiologíaRESUMEN
Three experiments were conducted to determine growth performance, body composition changes, and adipocyte characteristics of male broilers subjected to early-life feed restriction. The purpose of Experiment 1 was to determine 42-d growth performance and body composition changes. Treatments used were full-fed control and 50% physical feed restriction during the period 6 to 12 d of age. Experiment 2 was conducted to determine the adipocyte characteristics during and after feed restriction to 42 d of age. An additional treatment involved gradual refeeding following the feed restriction period. Experiment 3 was designed to test the effect of feeding different types of dietary fat during realimentation on the abdominal fat pad (AFP) size, and lasted until 18 d of age. Three types of fats were tested, namely animal-vegetable (A-V) blend, flax oil, and animal tallow, each represented by full-fed and feed-restricted treatments. Complete compensatory growth by feed-restricted birds relative to controls was not achieved by 42 d in either Experiments 1 or 2. Early feed restriction resulted in lower body fat percentage at 12 d (P < 0.05), although by 42 d a higher rate of fat deposition mainly by hypertrophy of adipocytes resulted in no difference in fatness. Gradual reintroduction into ad libitum feeding did not alter such adipocyte hypertrophy nor improve compensatory growth response during refeeding. There was consistent improvement in feed efficiency associated with early-life feed restriction (P < 0.05). The use of different types of dietary fat did not effect the AFP when expressed as percentage body weight. Birds that were fed A-V blend during the refeeding period had bigger AFP (grams per bird), a situation that is attributable to differences in body weight. Attainment of growth compensation by the feed-restricted broilers apparently requires a more prolonged growth period or a less severe feed restriction program than that used here. Saturation of dietary fat has no effect on realimentation characteristics of the broiler.
Asunto(s)
Adipocitos/citología , Composición Corporal , Pollos/crecimiento & desarrollo , Privación de Alimentos/fisiología , Tejido Adiposo/anatomía & histología , Tejido Adiposo/efectos de los fármacos , Animales , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/farmacología , Ácidos Grasos/administración & dosificación , Ácidos Grasos/farmacología , Masculino , Factores de Tiempo , Aumento de Peso/fisiologíaRESUMEN
Two experiments were conducted with broilers to determine the effect of early feed restriction and realimentation on metabolic heat production and changes in sizes of digestive organs. An indirect open circuit calorimeter was used. Treatments were a full-fed control (FF) and a feed-restricted group (FR). Feed during the restriction period (6 to 12 d) for the FR birds was limited to 50% of voluntary feed intake of the FF birds. This was followed by realimentation period when all birds were provided feed for ad libitum consumption. The purpose of Experiment 1 was to measure basal metabolic rate (BMR), and Experiment 2 was designed to measure 36-h fasting metabolic rate (FMR), in both cases during time of restriction and realimentation. At the end of the 36-h unfed period, birds were killed and their digestive organs excised, blotted, and weighed. The FR birds showed significantly (P < .01) lower BMR compared with the FF birds during the restriction period. This lower BMR did not carry over into the refeeding period, when there was no difference between the two treatments. Thirty-six-hour FMR, like the BMR was also lower for FR compared with FF birds, but only during the period of restriction. Weights of digestive organs (expressed as a percentage of BW) during restriction were generally heavier for FR compared with FF birds. Measurements of organ weights taken during realimentation show significantly (P < .05) heavier liver and pancreas for FR compared with FF birds. Results of these experiments suggest that lower MR of "restricted-refed" birds does not play a role in the ability of the birds to show improved feed efficiency and growth compensation. Greater feed intake relative to BW and its associated digestive adaptations seem to be contributing factors to any growth compensation.
Asunto(s)
Regulación de la Temperatura Corporal/fisiología , Pollos/fisiología , Ingestión de Alimentos , Metabolismo Energético , Privación de Alimentos , Alimentación Animal/análisis , Animales , Metabolismo Basal , Fenómenos Fisiológicos del Sistema Digestivo , Masculino , Tamaño de los Órganos/fisiología , Aumento de PesoRESUMEN
An experiment was conducted to determine growth and carcass characteristics of male broilers subjected to varying periods of early nutrient restriction. Nutrient restriction was achieved by feeding a starter diet in which the major ingredients were replaced with 50% oat hulls. Five treatments involved feeding this diluted diet for 6 d, either continuous or split into shorter periods in different ways, all starting at 6 d of age. On completion of the 6 d of nutrient restriction, all birds received undiluted starter diet, followed by grower and finisher diets to trial termination at 49 d. All birds fed the diluted diet exhibited reduced nutrient intake. Complete growth compensation by all birds that previously received the diluted diet was attained by 35 d, due largely to their superior (P < .05) feed efficiencies relative to the control birds during realimentation. Varying the period of nutrient restriction did not affect growth compensation. Birds that received the diluted diet for 6 continuous d tended to be leaner at 42 d compared with those that consumed the diluted diet for shorter periods. This latter effect may relate to variable ME intake. There was no statistical difference in other carcass characteristics measured at both 42 and 49 d of age.
Asunto(s)
Pollos/crecimiento & desarrollo , Privación de Alimentos/fisiología , Animales , Ingestión de Alimentos , Masculino , Factores de Tiempo , Aumento de PesoRESUMEN
The effect of beak trimming at different ages on feed consumption and growth of meat-type guineas (Numida meleagris) up to 12 wk of age was investigated. In the first experiment, beaks of birds were trimmed at 7, 28, 49, and 70 days, respectively. In the second experiment, beak trimming was done at 42, 49, 56, and 63 days, respectively. Body weight, feed consumption, and mortality were measured first at 4 wk and weekly thereafter in both experiments. Beak trimming of keets at 7 days, significantly (P less than .05) reduced body weights at 4, 8, and 12 wk whereas beak trimming at 70 days significantly (P less than .05) reduced body weights at 12 wk. Beak trimming at other ages did not produce significant differences in body weights or feed conversions. Mortality was low (2 to 4%) throughout.
Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Pico/cirugía , Peso Corporal , Aves de Corral/crecimiento & desarrollo , Factores de Edad , AnimalesRESUMEN
The effect of dietary bacitracin on the growth and feed conversion of guineas has been investigated using graded levels of the antibiotic. The treatments were 0, 11, 22, and 45 mg bacitracin/kg diet. Poorest live weights were recorded by unmedicated guineas. Keets given bacitracin at 11 mg/kg recorded significantly higher live weights (P less than .05) than unmedicated chicks. Best live weights were obtained at a supplementation level of 22 mg/kg; supplementation to 45 mg/kg gave no further growth improvement.