Energy efficiency in grazing lambs differing in sire body size, determined by the in vitro respiration rate and weight of liver and rumen

The energy efficiency of four group of lambs sired by rams of different body size was inferred from observation of liver and rumen weights and in vitro respiration rates (both total and the part attributable to sodium, potassium ATPase activity). The animals were raised in a common grazing-dependent environment from birth (September 1996) until reaching a market weight of 42.5 ± 0.9 kg (December 1997). The four groups (four ewes and four wether lambs per group) were progeny of Corriedale and Romney Marsh dams with sires of the Hampshire Down (H), Texel (T), and Ile France (I) breed, or of the same breed as the dam, as the control (C). At slaughter, livers and rumens were weighed, and in samples (5-10 g) of the caudal lobule and ventral sac, respectively, oxygen consumption was measured polarographically. The Na+, K+-ATPase dependent respiration was measured as the difference in O2 intake before and after the addition of 1 mMof ouabain. The genotypes did not affect mean daily gain (86.2 ± 2.0 g). Neither were relative weights of liver and rumen (16.2 ± 0.2 and 21.3 ± 0.9 g/kg of body weight, respectively) nor in vitro O2 consumption in fresh liver tissue (63.0 ± 2.4 µmol h-1g-1) affected by sire breed. For fresh ruminal papillae tissue there were differences (P<.05), but of small magnitude, among groups in O2consumption (T, 8.0, C, 8.7; I, 9.5; and H, 10.3 µmol h-1g-1). In all breed groups Na+, K+-ATPase dependent respiration accounted for 30 to 34% of the total O2 intake in liver and rumen tissues. It is concluded that all four groups of lambs gained weight with essentially the same energy efficiency in this study under conditions of nonintensive nutrition

Thermal behavior of myofibrillar proteins from the adductor muscles of scallops : A differential scanning calorimetric study (DSC)

Muscles and different proteins obtained from scallops (Chlamys tehuelchus and Zygochlamys patagonica) were analyzed. In both species of scallop, the thermograms of striated and smooth muscles showed two endothermic transitions. The T max values corresponding to striated and smooth muscles from C. tehuelchus were 53.2, 79.0°C and 52.7, 78.0°C, respectively. The T max corresponding to striated and smooth muscles of Z. patagonica were 55.0, 79.2°C and 54.7, 78.7°C, respectively. No significant differences were observed between the thermal transitions of myofibrils and actomyosin of both types of muscles from both species of scallop. Irrespective of the species, the thermal stability decreased when the pH of the muscles was increased. The increase in ionic strength greatly affected T max, the ΔH total and the ΔH of the first transition. A significant decrease in ΔH total and ΔH corresponding to both transitions was observed, particularly in the striated muscles of Zygochlamys patagonica. These results indicate a major sensitivity of the adductor muscles of Zygochlamys to changes in the chemical environment.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA

Thermal behavior of myofibrillar proteins from the adductor muscles of scallops : A differential scanning calorimetric study (DSC)

Muscles and different proteins obtained from scallops (Chlamys tehuelchus and Zygochlamys patagonica) were analyzed. In both species of scallop, the thermograms of striated and smooth muscles showed two endothermic transitions. The T max values corresponding to striated and smooth muscles from C. tehuelchus were 53.2, 79.0°C and 52.7, 78.0°C, respectively. The T max corresponding to striated and smooth muscles of Z. patagonica were 55.0, 79.2°C and 54.7, 78.7°C, respectively. No significant differences were observed between the thermal transitions of myofibrils and actomyosin of both types of muscles from both species of scallop. Irrespective of the species, the thermal stability decreased when the pH of the muscles was increased. The increase in ionic strength greatly affected T max, the ΔH total and the ΔH of the first transition. A significant decrease in ΔH total and ΔH corresponding to both transitions was observed, particularly in the striated muscles of Zygochlamys patagonica. These results indicate a major sensitivity of the adductor muscles of Zygochlamys to changes in the chemical environment.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA

Thermal behavior of myofibrillar proteins from the adductor muscles of scallops: a differential scanning calorimetric study (DSC)

Muscles and different proteins obtained from scallops (Chlamys tehuelchus and Zygochlamys patagonica) were analyzed. In both species of scallop, the thermograms of striated and smooth muscles showed two endothermic transitions. The Tmax values corresponding to striated and smooth muscles from C. tehuelchus were 53.2, 79.0ºC and 52.7, 78.0 ºC, respectively. The Tmax corresponding to striated and smooth muscles of Z. patagonica were 55.0, 79.2ºC and 54.7, 78.7ºC, respectively. No significant differences were observed between the thermal transitions of myofibrils and actomyosin of both types of muscles from both species of scallop. Irrespective of the species, the thermal stability decreased when the pH of the muscles was increased. The increase in ionic strength greatly affected Tmax, the deltaH total and the deltaH of the first transition. A significant decrease in deltaH total and deltaH corresponding to both transitions was observed, particularly in the striated muscles of Zygochlamys patagonica. These results indicate a major sensitivity of the adductor muscles of Zygochlamys to changes in the chemical environment

Thermal behavior of myofibrillar proteins from the adductor muscles of scallops : A differential scanning calorimetric study (DSC)

Muscles and different proteins obtained from scallops (Chlamys tehuelchus and Zygochlamys patagonica) were analyzed. In both species of scallop, the thermograms of striated and smooth muscles showed two endothermic transitions. The T max values corresponding to striated and smooth muscles from C. tehuelchus were 53.2, 79.0°C and 52.7, 78.0°C, respectively. The T max corresponding to striated and smooth muscles of Z. patagonica were 55.0, 79.2°C and 54.7, 78.7°C, respectively. No significant differences were observed between the thermal transitions of myofibrils and actomyosin of both types of muscles from both species of scallop. Irrespective of the species, the thermal stability decreased when the pH of the muscles was increased. The increase in ionic strength greatly affected T max, the ΔH total and the ΔH of the first transition. A significant decrease in ΔH total and ΔH corresponding to both transitions was observed, particularly in the striated muscles of Zygochlamys patagonica. These results indicate a major sensitivity of the adductor muscles of Zygochlamys to changes in the chemical environment.Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA

Oxidative stress and genotoxicity in the South American Cichlid, Australoheros facetus, after short-term sublethal exposure to endosulfan

Short-term responses at the antioxidant enzymatic systems, together with genotoxic effects were studied in the freshwater fish Australoheros facetus, exposed to endosulfan (ES) (0.02, 0.5, 5, 10 lg/L) for 24 h. Brain was the most responsive organ, showing inhibition of the enzymatic systems together with an increase of hydrogen peroxide (H2O2) content. Concentration-dependent inhibition was observed for superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) with IC25 values of 0.012, 0.017, 0.018 lg/L, respectively. In liver, a similar behavior was observed for SOD with IC25 values of 2.22 lg/L. In addition, increased thiobarbituric acid reactive substances (TBARs) at 5 lg/L and H2O2 at 5 and 10 lg/L were observed. No effects were evidenced on ethoxyresorufin O-deethylase (EROD), glutathione-S-transferase (GST), GR and CAT activities. In gills, only H2O2 decreased at 0.5 and 5 lg/L ES. Genotoxic effects were detected by the increase of the frequency of both, nuclear abnormalities (NA) at 0.02 lg/L and micronucleus (MN) at 5 lg/L. Environmentally realistic concentrations of ES exerted toxic responses in A. facetus, encouraging the further field validation of the observed pattern (tissue specificity, sensitiveness and concentration-response relationship) as a potential suit of biomarkers for assessing acute sublethal effects in A. facetus under short-term pulsed exposure to ES.Fil: Crupkin, Andrea Carina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ecotoxicología; ArgentinaFil: Carriquiriborde, Pedro. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; ArgentinaFil: Mendieta, Julieta Renee. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Panzeri, Ana M.. Universidad Nacional de Mar del Plata. Facultad de Cs.exactas y Naturales. Departamento de Biologia. Laboratorio de Genetica; ArgentinaFil: Ballesteros, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; ArgentinaFil: Miglioranza, Karina Silvia Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ecotoxicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Menone, Mirta Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas. Laboratorio de Ecotoxicología; Argentin