The woodlice, Porcellio scaber (Latreille, 1804), is a terrestrial isopod. Its metabolic reserves and body size are important factors affecting the fitness attributes, such as survival at unfavourable conditions. The larger and heavier individuals did not survive longer than smaller individuals. Amount of glycogen and body weight (fresh and dry) appeared to be an inapplicable parameter in the observed differences among individuals during survival at low temperature. We compared three treatments (long day, short day, natural autumn conditions) of Porcellio scaber and found differences in amount of energy reserves and cryoprotectants.

Abstract Winter energy management in small passerines living year-round in boreal or alpine areas presumably results in strong selective pressure since they need to find food, at a time when natural resources diminish and become less available, and energy requirements increase dramatically. In this thesis energy management during the non-breeding season was studied in three species of tits (Parus spp.), from three different populations: Coll de Pal (Spanish Pyrenees), Lund (Southern Sweden) and Oulu (Northern Finland). Energy management strategies vary significantly between species and among populations and individuals of the same species. Such differences may depend on several environmental factors, food predictability and individual characteristics. Birds from the studied populations appear to react to energetic challenges on a short-term basis and in a highly flexible way. The coal tit (Parus ater) in Coll de Pal and the willow tit (Parus montanus) in Oulu, both hoarding species, relied mostly on short-term management of energy for winter survival. Social and residence status appeared to be the most important factors in determining the level of energy reserves, underlining the importance of food predictability for energy management in wintering tits. Further studies were carried out on two distinct populations of great tit (Parus major) exposed to different winter hardiness. Birds from both populations increased their resting metabolic rate (MR) with experimentally decreasing ambient temperatures. Birds from Oulu maintained higher expenditures than birds from Lund in all cases, but also experienced higher energetic cost of thermoregulation at the lowest temperatures. The differences probably did not arise from a differential insulation capacity between populations, despite the differences in plumage structure found, but from a differential metabolic acclimatization. Birds from Lund probably became hypothermic at the lowest temperatures, which may have exceeded the levels they were acclimatized for. The observed differences in basal MR in laboratory conditions were consistent in wild birds throughout the non-breeding season. Birds from both populations experienced similar patterns of variation in basal MR, with expenditures increasing with mass but decreasing with day length, size and age. Great tits modulate their energy expenditure in a flexible way as a means for surviving the non-breeding season. Further, despite such flexibility, populations appear to be locally adapted for such metabolic acclimatization. These results may have important implications on their life-history and distribution. Winter acclimatization appears to be a complex set of entangled strategies that are based on a metabolic adjustment to cope with changing energy requirements. Other mechanisms that apparently play a secondary role, for example the long term management of reserves through fattening or hoarding, or conserving heat through hypothermia and by developing a better insulative plumage, are certainly important emergency strategies that in natural conditions may explain how some populations can endure winter conditions.

A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

No description available.

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / The body condition score (BCS) is a method of assessment of the animal's energy reserves and it was developed based on the characteristics of mobilization/ deposition of cow’s fat cows with degree of Holstein blood Therefore, it is not known whether this methodology is appropriate for crossbred cows. Thus, the objective with this study to investigate the relationship between the back fat thickness (BFT) and the body condition score (BCS) in crossbred cows (Holstein - Zebu) during the transition period and early lactation, and to relate these findings with productive and metabolic parameters. A total of 108 Holstein - Zebu dairy cows from six farms were randomly selected and divided into three groups according to their production phase at the time: PP group (0 to 4 weeks antepartum; n = 30 animals); L4 group (0-4 weeks postpartum; n = 15 animals); L + 5 group (5-14 weeks postpartum; n = 63 animals). Correlation and regression analysis were used to describe the relationship between the BCS, BFT and body weight (BW) variables. For productive and metabolic evaluation of the animals we made a multivariate cluster analysis to order the distribution of these animals in homogeneous BFT groups within each study phase. Analysis of variance showed significant differences (P <0.05) among the three groups for the three variables BCS, BFT and BW. The BW variable showed a weak correlation with the BCS and BFT variables r = 0.28 and r = 0.38, respectively. In groups PP and L + 5 there were strong and direct correlation between BFT and BCS variables, r = 0.78 and r = 0.71, respectively. The BFT was sensitive to changes in metabolites albumin, total cholesterol and total protein. In addition to being a good indicator of the production of milk and density, as well as proportions of total solids and lactose. / O escore de condição corporal (ECC) é um método de avaliação das reservas energéticas do animal e foi desenvolvido com base nas características de mobilização/deposição de gordura de vacas com grau de sangue Holandês. Por isso, ainda não se sabe se essa metodologia é apropriada para vacas mestiças. Desta forma, objetivou – se com esse estudo verificar a relação entre a espessura de gordura subcutânea na garupa (EGG) e o ECC de vacas mestiças (Holandês x Zebu) durante o período de transição e fase inicial de lactação, e relacionar esses achados com parâmetros produtivos e metabólicos. Um total de 108 vacas leiteiras Holandês x Zebu pertencentes a seis propriedades rurais foram escolhidas aleatoriamente e divididas em três grupos de acordo com sua fase de produção naquele momento: grupo PP (0 a 4 semanas pré-parto; n=30 animais); grupo L4 (0 - 4 semanas pós-parto; n = 15 animais); grupo L+5 (5 - 14 semanas pós – parto; n=63 animais). Análises de correlação e regressão foram usadas para descrever a relação entre as variáveis ECC, EGG, peso corporal (PC). Para avaliação produtiva e metabólica dos animais foi feito uma análise multivariada de agrupamento visando à distribuição dos mesmos em grupos de EGG homogêneos dentro de cada fase estudada. A análise de variância mostrou que houve diferenças significativas (P<0,05) entre os três grupos para as três variáveis ECC, EGG e PC. A variável PC apresentou uma fraca correlação com as variáveis ECC e EGG, com r = 0,28 e r = 0,38, respectivamente. Nos grupos PP e L+5 houveram fortes e diretas correlações entre as variáveis EGG e ECC, com r = 0,78 e r = 0,71, respectivamente. O EGG foi sensível às mudanças dos metabólitos albumina, colesterol total e proteína total. Além de ser um bom indicador da produção e densidade do leite, como também das proporções de sólidos totais e lactose.

Pour faire face à des perturbations environnementales, les organismes ont développé des défenses antitoxiques couramment utilisés comme biomarqueurs dans l'évaluation de la qualité des milieux. Cependant, de nombreux facteurs confondants comme la température ou le genre, influencent la réponse de ces biomarqueurs. Il est ainsi nécessaire de connaitre les effets de ces facteurs afin d'imputer correctement la réponse biologique mesurée à la présence de polluants. Dans ce contexte, nous avons choisi d'étudier l'influence d'un parasite acanthocéphale, Polymorphus minutus, transmis horizontalement et de microsporidies à transmission verticale, sur les réponses physiologiques de leur hôte, Gammarus roeseli, un crustacé amphipode d'eau douce d'intérêt écotoxicologique. Pour cela, nous avons choisi d'étudier le glutathion, tripeptide jouant un rôle central dans les systèmes antitoxiques, sa synthèse (i.e. activité gamma-glutamylcystéine ligase), les réserves énergétiques (i.e. lipides, glycogène, protéines) et un biomarqueur d'effets toxiques, le malondialdéhyde. L'influence du parasitisme a été appréhendé dans différents cas d'études: (i) chez G. roeseli infecté par P. minutus, (ii) chez G. roeseli infecté par des microsporidies (Dictyocoela roeselum essentiellement) et (iii) chez G. roeseli co-infecté par ces deux types de parasite. Chaque cas d'étude a été réalisé en absence de stress et lors d'une exposition au cadmium. Nous avons mis en évidence qu'en absence de contamination, la présence de P. minutus et une co-infection par P. minutus et D. roeselum affectent les biomarqueurs de G. roeseli. Après exposition au cadmium, la présence de parasites (i.e. infection simple ou co-infection) modifie la mobilisation des défenses antitoxiques et accentue les effets toxiques subits par l'hôte. Les résultats obtenus au cours de ce travail mettent en avant le caractère confondant du parasitisme en écotoxicologie et souligne l'importance de prendre en compte ce paramètre lors de l'évaluation de la qualité des milieux / To cope with environmental disturbances, organisms have developed antitoxic defenses commonly used as biomarkers in environmental risk assessment. However, many confounding factors such as temperature and gender could influence biomarker responses. It seems hence necessary to investigate their effects, in order to attribute biological responses only to pollutants. In this context, we investigated the influence of parasitism by studying the acanthocephalan parasite Polymorphus minutus, horizontally transmitted, and microsporidia parasites, vertically transmitted, on the physiological responses of their common host, the freshwater amphipod Gammarus roeseli, a classical model used in ecotoxicology. We investigated the glutathione, a tripeptide having a key role in antitoxic systems, its synthesis (i.e. gamma-glutamylcysteine ligase activity), energy reserves (i.e. lipids, glycogen, proteins) and a toxicity biomarker, the malondialdehyde. The influence of parasitism was considered in different studies: (i) in G. roeseli infected by P. minutus only, (ii) in G. roeseli infected by microsporidia (mainly Dictyocoela roeselum) and (iii) in G. roeseli coinfected by both parasites. Each study was carried out in absence of pollutants and under cadmium stress. We highlighted that, in the absence of contamination, only P. minutus and the co-infection affect the G. roeseli biomarker assessments. After cadmium exposure, the presence of parasites (i.e. single infection or co-infection) influences the mobilization of antitoxic defences, and accentuates toxic effects in their hosts. Our results underline the confounding nature of parasitism in ecotoxicology and thus, highlight the importance to take into account this parameter in the environmental risk assessment