Search

BACKGROUND: Insulin resistance in horses is an emerging field of interest as it is thought to be a contributing factor in the pathogenesis of many equine conditions. OBJECTIVES: The objectives of the present study were to determine the effects of long-term oral administration of L-carnitine on insulin sensitivity, glucose disposal, plasma leptin concentrations and acylcarnitine spectrum both in plasma and urine. ANIMALS AND METHODS: Six 3-year-old healthy warmblood geldings were used. In a double blind 2 × 2 Latin square design at a dosage of 100 mg/kg body weight (BW)/day for 28 days the effects of oral supplementation of L-carnitine (as fumarate) were assessed. Glucose disposal and insulin sensitivity were measured by means of the euglycemic-hyperinsulinemic clamp technique. Radioimmunoassays were used to determine plasma leptin and insulin concentrations. Electrospray tandem mass spectrometry was used to assess acylcarnitines both in plasma and urine. Statistical analysis was performed using a linear mixed-effects model and P values

The nutritional profile of the leaves and stem of Stevia rebaudiana, and their potential utilization in an animal model were studied. Stevia leaves and stem had 16% and 6.7% crude protein and were low in fat content (2.6 and 1.1%) respectively. The fatty acid profile of fat showed a preponderance of unsaturated fatty acids (65.8% and 71.4% for leaves and stem respectively). Linolenic acid was the most abundant fatty acid in stevia leaf oil (36%) whereas linoleic acid was the highest in stems (38%). The crude fiber contents on dry fat free basis were 6.8% and 45.4% for leaves and stem respectively. The K content of stevia leaves and stem were comparable; Ca, Mg, Fe, Cu, Zn and Mn were higher in leaves and the opposite was true for Na. The tests with broiler chickens showed that apparent, nitrogen corrected, and true metabolisable energy values for leaves were 2113, 2098 and 2223 kcal/kg and for stems 1573, 1554 and 1675 kcal/kg respectively. Retention of the protein from the leaves and stems by chickens was 63% and 65.7% respectively. Stevia leaves contain other nutritional attributes besides of the sweetening components. Se estudió el perfil nutricional de hojas y tallos de Stevia rebaudiana y su potencial empleo en un modelo animal. Las hojas y tallos de Stevia rebaudiana tienen 16% y 6,7% de proteína bruta y bajo contenido de grasa (2,6 y 1,1%) respectivamente. La grasa extraída mostró un predominio de ácidos grasos insaturados (65,8% y 71,4% para hojas y tallos respectivamente). El ácido graso más abundante en la hoja fue el linolénico (36%) y en el tallo, el linoleico (38%). La fibra bruta sobre materia seca desgrasada supuso el 6,8% para hojas y 45,4% para tallo. El contenido de K de hojas y tallos fue similar, la concentración de Ca, Mg, Fe, Cu, Zn, Mn fue mayor en las hojas y al contrario para Na. Las pruebas con broilers establecieron que los valores de energía aparente, corregida para N y metabolizable verdadera, fueron 2113, 2098 y 2223 kcal/kg en hojas, y 1573, 1554 y 1675 kcal/kg en tallos respectivamente. La retención de proteína foliar y de los tallos por los broilers fue 63 y 65,7% respectivamente. El contenido de esteviósido de las hojas fue 6,5% y el de rebaudiósido A de 2,3%. Los valores correspondientes para los tallos fueron 0,69% y 0,3%. Las hojas de Stevia rebaudiana contienen otros atributos nutricionales además de la alta concentración de componentes endulzantes (esteviósido y rebaudiósido A).

International audience; This study was designed to test the effect of pre- and post-hatch temperature conditioning or a combination of both, on the acquisition of heat tolerance during the adult life of broiler chickens. Nine hundred hatching eggs produced by Cobb broiler breeders were incubated at standard incubation conditions until d 16. Half of the eggs were subjected to temperature conditioning for 3 h/day (39.5 degrees C, 65% relative humidity (RH)) at d 16, 17 and 18 of incubation (T group) while the other half Control group (C group) were kept at standard incubation conditions. From the end of d 18 until end of incubation, embryo heat production (HP), gas partial pressure in the air chamber at IP, and blood parameters (T(3) and corticosterone) were measured. Also, hatching time for individual chick, body temperature (Tb) and body weight (BW) and the number of hatched chicks were recorded. Hatched chicks were raised under regular conditions. At the age of 3 d, the chicks of each incubation condition group were divided into 2 groups: half of the chicks of each group (C and T) were subjected to thermal conditioning (41.0 degrees C for 6 hours). The other half of the chicks was used as control. The 4 groups of broilers were reared until 42 d of age. During post-hatch period, Tb, blood parameters and BW were again measured. At 42 d all broilers were heat challenged at 35 degrees C for 6 h. After heat challenge, mortality was recorded and blood samples were collected. The results indicate that thermal conditioning during incubation had no effect on hatchability of eggs but prolonged incubation duration, decreased T3 (at IP), corticosterone (at IP and hatch), HP and Tb. Overall, at 3 d post-hatch, prenatal condition increased while post-natal conditioning decreased corticosterone levels. Heat challenge at 42 d post-hatch decreased T3 levels in the TC group and increased corticosterone levels in postnatally conditioned group. Differences between BW become obvious from 28 d post-hatch and were in the following order: TT > CC = CT > TC. At 42, the highest BW was obtained in the broilers of TC group. Heat conditioning at 3 d of age improved heat tolerance in response to heat challenge at 42 d. post-hatch whereas prenatal treatment had a strong negative effect. It is concluded that heat treatment during incubation or during post-hatch life induces completely different effects.

Male chickens of two pure broiler breeder (S1 and S2) and a broiler cross line Ross 308 (BC) were reared from 0-35 days of age and were fed three dietary regimes with different lysine to apparent metabolizable energy (Lys/AME) ratios. Chickens were subjected to low ambient temperatures to stimulate the development of ascites. The objectives of the experiment was to evaluate effects of different ratios lysine to apparent metabolizable energy (Lys/AME) in diets, at different ages, on following indicators in metabolism for ascites susceptibility: arterial and venous blood gas pressures ( pa CO2, pv CO2, pa O2 and pv O2), heat production (Hp), plasma thyroid hormone concentrations (triiodothyronine, T3 and thyroxine, T4) and proportional organ weights (lung, liver and heart). Measurements were carried out at 2 and 5 wk of age. The ascites susceptible sire lines displayed, at different ages, marked higher pv CO2 and arterial pa CO2 values and lower plasma thyroid hormone concentrations compared to the less ascites susceptible BC line. The latter line showed heavier proportional lung weights (P

Made available in DSpace on 2022-04-28T18:55:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-02-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The present study was conducted to evaluate the zootechnical parameters and age related changes in physiological responses of broiler chickens exposed to hot environment from early age onwards. The broiler chickens were exposed to high temperature (30°C) at 15 d of age and maintained to Day 38 or maintained under thermoneutral environment (control). No significant decrease in feed consumption (FC) and body weight (BW) gain was observed in high temperature group after 7 d of exposure, but in the subsequent period, heat exposure lowered BW and FC, compared to control group. However, the weight gain was not significantly changed after 24 d of exposure, and the feed efficiency was not affected throughout the experimental period. The venous pCO2 pressure was only significantly decreased by temperature after 24 d of heat exposure. The glucose, non-esterified fatty acid (NEFA), triglyceride (TG), glucose, lipid peroxidation (LPO), creatine kinase (CK), and corticosterone were not influenced by the temperature treatment. The significant decrease in uric acid and increase in lactate concentration due to high temperature were observed respectively at 28 and 35 d of age. The concentrations of triiodothyronine (T3) and thyroxine (T4) were changed oppositely at 28 d of age, as T3 was decreased and T4 was elevated by high temperature. However, the concentration of T4 in plasma was decreased whereas T3 was not changed at 38 d of age. The relationships between the blood parameters were changed due to the temperature treatment, suggesting that not only absolute values but also have to be considered when studying the effects of a particular treatment on physiological functioning. These results suggest the growth and physiological responses of broiler chickens, exposed to high temperature from early age onwards, differed at different stages of acclimation. The process of heat acclimation is related to the mode of heat exposure imposed and is not only reflected in the changes in the absolute concentrations, but also in the correlations among the blood indices. Shandong Agricultural University CNPq UNESP, Jaboticabal, SP Lab. Anim. Physiol. Immunol. Dom. A. Katholic University of Leuven Lab. Anim. Physiol. Immunol. Dom. A. Katholic University of Leuven, Kasteelpark Arenberg 30, 3001 Leuven UNESP, Jaboticabal, SP

Made available in DSpace on 2022-04-29T08:47:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-04-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The present experiment was aimed to study the effects of an isocaloric substitution of fat by carbohydrate calories - while maintaining the same CP content - on some endocrine parameters and key metabolites of the lipid (L), protein (CP) and carbohydrate (CHO) metabolism and muscle cell membrane integrity of broiler chickens. Ninety male broiler chicks (Cobb) were obtained at 1-day old and raised in an environmentally controlled room. Food and water was provided ad libitum. At day 7, the chicks were provided with the experimental diets: Control diet (CON: 20% CP; 9.1% L; 39.6% CHO), Low lipid diet (LowL: 22% CP; 3.36% L; 59.7% CHO), and low carbohydrate diet (LowCHO: 22% CP; 8.09% L; 46.7% CHO). The chickens fed the CON manifested the best growth rate and feed conversion compared to both other groups. The CON chickens showed the highest plasma T3 concentrations at 14 days of age as compared to both LowL and LowCHO chickens. At 35 days of age however, LowL chickens were characterized by the highest plasma T3 levels. Overall, CON birds had the highest plasma T4 levels (P < 0.0001) compared to LowL and LowCHO chickens. Plasma corticosterone levels were not affected by diet composition. Glucose levels increased towards the end of the experimental period, but there was no overall effect of diet composition on plasma glucose levels. Chickens fed the CON diet were consistently characterized by the highest plasma uric acid levels compared to LowL and LowCHO chickens. Irrespectively of diet, plasma triglyceride levels were high at 14 days of age, then decreased and finally increased again during the last week. This latter increase was most pronounced for the CON chickens and is congruous with their high fat deposition. At 28 days of age, a significant effect of diet was observed, as CON birds had lower plasma free fatty acid (FFA) levels compared to LowL but not to LowCHO chickens. However there was no overall effect of diet composition on plasma FFA levels. Creatine kinase (CK) activities increased significantly with age and were consistently higher in CON chickens. In conclusion, fast growth in broiler chickens is positively correlated with catabolism of protein from dietary or endogenous origin and (muscle) cell membrane disruption as reflected in high plasma uric acid levels and CK activity, respectively. The currently investigated substitution of fat by CHO had no marked effects on endocrine functioning and intermediary metabolism, but this does not exclude that larger substitutions between both nutrients can have an effect. CNPq Lab. for Physiol. of Dom. Animals KULeuven, Heverlee UNESP-Jaboticabal, SP Station de Recherches Avicoles INRA, Nouzilly Laboratory of Animal Nutrition Ghent University, Merelbeke Department of Animal Science KU Leuven, Kasteelpark Arenberg 30, 3001 Leuven UNESP-Jaboticabal, SP