Feeding, body condition and reproductive investment of Astyanax intermedius (Characiformes, Characidae) in relation to rainfall and temperature in a Brazilian Atlantic Forest stream

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variation in fat mobilization during early lactation differently affects feed intake, body condition, and lipid and glucose metabolism in high-yielding dairy cows.

Fat mobilization to meet energy requirements during early lactation is inevitable because of insufficient feed intake, but differs greatly among high-yielding dairy cows. Therefore, we studied milk production, feed intake, and body condition as well as metabolic and endocrine changes in high-yielding dairy cows to identify variable strategies in metabolic and endocrine adaptation to overcome postpartum metabolic load attributable to milk production. Cows used in this study varied in fat mobilization around calving, as classified by mean total liver fat concentrations (LFC) postpartum. German Holstein cows (n=27) were studied from dry off until d 63 postpartum in their third lactation. All cows were fed the same total mixed rations ad libitum during the dry period and lactation. Plasma concentrations of metabolites and hormones were measured in blood samples taken at d 56, 28, 15, and 5 before expected calving and at d 1 and once weekly up to d 63 postpartum. Liver biopsies were taken on d 56 and 15 before calving, and on d 1, 14, 28, and 49 postpartum to measure LFC and glycogen concentrations. Cows were grouped accordingly to mean total LFC on d 1, 14, and 28 in high, medium, and low fat-mobilizing cows. Mean LFC (±SEM) differed among groups and were 351±14, 250±10, and 159±9 mg/g of dry matter for high, medium, and low fat-mobilizing cows, respectively, whereas hepatic glycogen concentrations postpartum were the highest in low fat-mobilizing cows. Cows in the low group showed the highest dry matter intake and the least negative energy balance postpartum, but energy-corrected milk yield was similar among groups. The decrease in body weight postpartum was greatest in high fat-mobilizing cows, but the decrease in backfat thickness was greatest in medium fat-mobilizing cows. Plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate were highest around calving in high fat-mobilizing cows. Plasma triglycerides were highest in the medium group and plasma cholesterol concentrations were lowest in the high group at calving. During early lactation, the decrease in plasma glucose concentrations was greatest in the high group, and plasma insulin concentrations postpartum were highest in the low group. The revised quantitative insulin sensitivity check index values decreased during the transition period and postpartum, and were highest in the medium group. Plasma cortisol concentrations during the transition period and postpartum period and plasma leptin concentrations were highest in the medium group. In conclusion, cows adapted differently to the metabolic load and used variable strategies for homeorhetic regulation of milk production. Differences in fat mobilization were part of these strategies and contributed to the individual adaptation of energy metabolism to milk production.

Genetic covariance between indices of body condition and immunocompetence in a passerine bird

Background: Condition-dependence is a ubiquitous feature of animal life histories and has important implications for both natural and sexual selection. Mate choice, for instance, is typically based on condition-dependent signals. Theory predicts that one reason why condition-dependent signals may be special is that they allow females to scan for genes that confer high parasite resistance. Such explanations require a genetic link between immunocompetence and body condition, but existing evidence is limited to phenotypic associations. It remains unknown, therefore, whether females selecting males with good body condition simply obtain a healthy mate, or if they acquire genes for their offspring that confer high immunocompetence. Results: Here we use a cross-foster experimental design to partition the phenotypic covariance in indices of body condition and immunocompetence into genetic, maternal and environmental effects in a passerine bird, the zebra finch Taeniopygia guttata. We show that there is significant positive additive genetic covariance between an index of body condition and an index of cell-mediated immune response. In this case, genetic variance in the index of immune response explained 56% of the additive genetic variance in the index of body condition. Conclusion: Our results suggest that, in the context of sexual selection, females that assess males on the basis of condition-dependent signals may gain genes that confer high immunocompetence for their offspring. More generally, a genetic correlation between indices of body condition and imuunocompetence supports the hypothesis that parasite resistance may be an important target of natural selection. Additional work is now required to test whether genetic covariance exists among other aspects of both condition and immunocompetence.

Melanism, body condition and elevational distribution in the asp viper

Alternative morphotypes can confer important selective advantages in different habitats, whereas they can be penalized in other circumstances. In ectotherms, such as reptiles, the body colour can have direct effects on numerous aspects of their existence, such as thermoregulation or prey-predator interactions. Darker melanic individuals show lower skin reflectance and consequently heat up more rapidly and maintain optimal body temperatures more easily than lighter coloured individuals. As a consequence, melanistic individuals of diurnal species in cool areas may exhibit higher body condition, growth rate, survival and fecundity than lighter coloured individuals. Such advantages of dark coloration may be counterbalanced by a lower crypsis to predators and a decreased foraging efficiency. We investigated, in two montane populations of asp vipers Vipera aspis, the relationship between (1) colour polymorphism and body condition and length and (2) the coloration of individuals and their elevational distribution. We showed significant relationships between (1) the coloration, body condition and sex of individuals; (2) sexes and reproductive state and morph frequency; and (3) colour morphs that were distributed following an elevational gradient. Hence, colour polymorphism plays an important role in the ecology and evolution of the asp viper and is maintained through differential selective pressures.

(Table 1) Body condition and plasma POP concentrations of glaucous gulls from Bjørnøya, Svalbard archipelago

Behavioural field observations are increasingly being used in ecotoxicological research to identify potential adverse effects of exposure to persistent organic pollutants (POPs). We investigated thermal conditions inside the nest and parental behaviour of glaucous gulls, Larus hyperboreus, breeding in the Norwegian Arctic in relation to the concentrations of major classes of POPs (organochlorines, brominated flame retardants and metabolically derived products) accumulated in their blood. Most notably, nest temperature was negatively correlated with the concentrations of the sum of DDT, sum of PCB and several quantitatively minor POP classes within the incubating parent. To investigate the relationship between incubation ability and parental POP exposure further, we experimentally increased the costs of incubation by artificially increasing the clutch size from two to four eggs. Clutch enlargement was followed by a decrease in nest temperature, but this drop in temperature was not associated with POP concentrations within the incubating parent. However, males, which had higher POP concentrations and lower white blood cell counts than females, seemed less able to maintain nest temperature. There was virtually no evidence to suggest that the sum of PCB or DDT were associated with changes in the time a bird spent incubating. However, there was some indication that nest site attendance by nonincubating males was negatively related to the sum of DDT, suggesting that nest protection may have been compromised. The results suggest that adverse effects of parental POP exposure may occur through suboptimal thermal conditions for embryo development and possibly increased egg predation risk.

Secular trends in height and weight among children and adolescents of the Seychelles, 1956-2006

Background: Few data is available on long-term secular trends in height and weight in children in countries in transition. We assessed the secular trends in height and weight among representative samples of children and adolescents from the Seychelles (African region). Methods: Weight and height data from all students of all schools in four selected school grades (kindergarten, 4th, 7th and 10th years) were collected by cross-sectional surveys for periods 1998-9 (3,676 boys, 3,715 girls) and 2005-6 (4,867 boys, 4,846 girls). Data from 1956-7 was extracted from a previously published report. Results: Height increased, in boys, by 1.6 cm/decade for the period 1956-7 to 1998- 9, and 1.1 cm/decade for the period 1998-8 to 2005-6; in girls, the corresponding figures were 0.9 cm/decade and 1.8 cm/decade. At age 15.5 years, boys/girls were taller by 10/13 cm in 2005-6 than in 1956-7. Weight increased, in boys, by 1.4 kg/decade for the period 1956-7 to 1998-9, and by 2.2 kg/decade for the subsequent period; the corresponding figures in girls were 1.1 kg/decade and 2.5 kg/decade. Conclusion: Marked upward secular trends in body height and weight were documented in children and adolescents aged <16 years in the Seychelles, consistent with large changes in socio-economic and nutritional indicators in the considered 50- year interval. However, indirect evidence suggests that the secular height gain reflects accelerated growth during childhood over time with less than commensurate impact on adult height. Conversely, the largely steeper secular increase in weight than height is consistent with a pediatric obesity epidemic.

Parental body condition does not correlate with offspring sex-ratio in Cory's shearwater

We analyzed offspring sex ratio variation in Mediterranean Cory's Shearwater (Calonectris d. diomedea) during two consecutive breeding seasons in two colonies. We test for differential breeding conditions between years and colonies looking at several breeding parameters and parental condition. We then explored the relationship between offspring sex ratio and parental condition and breeding parameters. This species is sexually dimorphic with males larger and heavier than females; consequently we expected differential parental cost in rearing sexes, or a greater sensitivity of male chicks to adverse conditions, which may lead to biased sex ratios. Chicks were sexed molecularly by the amplification of the CHD genes. Offspring sex ratio did not differ from parity, either at hatching or fledging, regardless of the colony or year. However, parental body condition and breeding parameters such as egg size and breeding success were different between years and colonies. Nevertheless, neither nestling mortality nor body condition at fledging varied between years or colonies, suggesting that male and female chicks were probably not differentially affected by variability in breeding conditions.

Effect of sibling competition and male carotenoid supply on offspring condition and oxidative stress

Early developmental conditions have major implications for an individual's fitness. In species where offspring are born simultaneously, the level of sibling competition for food access is intense. In birds, high sibling competition may subject nestlings to decreased growth rate as a result of limited food and increased levels of oxidative stress through high metabolic activity induced by begging behaviors. We manipulated the level of sibling competition in a natural population of great tits and assessed the consequences for nestling body condition and resistance to oxidative stress. In a full factorial design, we both augmented brood size to increase sibling competition and supplemented the male parents with physiological doses of carotenoids thereby doubling the natural carotenoid intake, aiming at increasing the males' investment in current reproduction and thereby decreasing sibling competition. Nestling body mass was reduced by the brood enlargement and enhanced by the carotenoid supplementation of fathers. Nestling resistance to oxidative stress, measured as total antioxidant defenses in whole blood, was not influenced by the treatments. Because nestlings experience high metabolic activities, an absence of an effect of sibling competition on free radicals production seems unlikely. Nestling body mass decreased and resistance to oxidative stress tended to increase with initial brood size, and hence these correlational effects suggest a trade-off between morphological growth and development of the antioxidant system. However, the result of the experimental treatment did not support this trade-off hypothesis. Alternatively, it suggests that nestling developed compensatory mechanisms that were not detected by our antioxidant capacity measure.

Efeito de estratégia de suplementação com concentrado no desempenho de cabras mestiças Saanen, em dois sistemas de produção

The experiment was carried out to evaluate the performances of cross breed Saanen dairy goats submitted to two strategies of supplementation with concentrate 30% of daily requirements in net energy (NRC, 1981) supplied by concentrate, from third week until the end of lactation (ESC. 1) or 60% of requirements from the 3rd to the 13th week of lactation and 15% from 14th until the end of lactation (ESC.2); and evaluate the animal response to these strategies of supplementation with concentrate in a semi-confined or pasture systems. Thirty one animals were used in a completely randomized design. The system of production affected the total intake of concentrate and total milk production; at pasture system the values for these two variables were higher. The supplementation with concentrate affected the total intake of concentrate and total production of milk and the relation of milk/consumption of concentrate. The highest value for relation of milk/consumption of concentrate and the least for the total consumption of concentrate were obtained at ESC. 1. Body weight affected of the system of production, resulting in a higher value to the system of pasture. Weight and body condition had different responses to he supplementation with concentrate according to the system of production. The semi-confined system ESC.2 resulted in a higher value to the body condition; the body weight was no affected. At pasture system the highest values for weight and body condition were obtained in the supplementation with concentrate ESC. 1. Reproductive parameters did not affect supplementation with concentrate and system of production.

Influencia de la edad fenotipo sexo y peso al sacrificio sobre los indicadores de calidad de los porcinos faenados en el camal de Azogues

La industria porcina ha conseguido mejorar los parámetros productivos con la finalidad de incrementar la rentabilidad y ser más competitivos. El objetivo de la presente investigación fue determinar la influencia de la edad, fenotipo, sexo y peso al sacrificio sobre los indicadores de calidad: Rendimiento de la Canal, Porcentaje Magro, Temperatura y pH en 457 porcinos faenados en el camal de Azogues, analizando por fenotipo a 420 animales mestizos y 37 criollos. Los porcinos mestizos presentaron una Edad media de 5±1,09 meses, Peso al Sacrificio 94,2±19,39 kg, Rendimiento a la Canal 83,5±2,02%, Porcentaje Magro 61,2±4,37%, T°C45m 37,5±1,14°, T°C2h 34,8±1,57°, pH45m 6,4±0,13 y pH2h de 6,1±0,13. Los animales criollos mostraron una Edad de 8,2±4,40 meses, Peso al Sacrificio 92,7±20,63 kg, Rendimiento a la Canal 75,9±3,32%, Porcentaje Magro 55,1±5,40%, T°C45m 36,9±1,10°, T°C2h 34,1±1,51°, pH45m 6,4±0,10 y pH2h 6,1±0,97. Se encontraron diferencias significativas (P<0,05) para el Rendimiento a la Canal y el Porcentaje Magro con respecto a la Edad y CC. Se determinó un 62,9% de canales mestizas muy magras. El 27% de las canales criollas fueron muy magras y 5,4% graso. Se obtuvo un 87% de canales mestizas normales y un 89% de canales criollas normales, de acuerdo al pH. El Peso al Sacrificio, CC y Edad de los animales mestizos (R2=15%) tienen poca influencia para la estimación del Porcentaje Magro, mientras que la Edad de los criollos (R2= 36%) indica una relación predictora baja. La CC y el Peso al Sacrificio del fenotipo mestizo (R2=36%) tienen una relación baja para la estimación del rendimiento a la canal. Existe una excelente relación predictora (R2=98%) entre la CC, Edad y Peso al Sacrificio de los animales mestizos para predecir la T°C45m y T°C2h.

Nursing regimens: Effects on body condition, return to postpartum ovarian cyclicity in Santa Ines ewes, and performance of lambs

The effects of nursing regimens on the body condition, onset of ovarian cyclicity postpartum and weaning weight of lambs were assessed in Santa Ines ewes. Thirty-two ewes were blocked according to parity, number of lambs, and body weight at lambing and within each block randomly allocated to treatments: continuous nursing (CN), controlled nursing (CN2) with two daily feedings for an hour after the 10th day postpartum, or early weaning (EW) with total separation from the lambs after the 10th day. The animals were evaluated from the 12th day postpartum until the first estrus or until 60th day. The dry matter and nutrients intake did not differ among treatments ( P>. 0.05) but did differ over time ( P<. 0.01). The weight, body condition score, serum concentrations of non-esterified fatty acids and prolactin, the percentages of ewes in estrus, of ewes that ovulated within 60th day and had ovulation silent, the period from lambing to estrus, ovulation and follicle with a diameter ≥5. mm and the maximum follicular diameter did not differ ( P>. 0.05) among the treatments. The percentage of ovulation until 30th day was greater ( P<. 0.05) in the EW group. The percentage of short luteal phases was higher in the CN2 and EW groups ( P=0.07) and normal luteal phases were higher in the CN group ( P=0.01). Lamb weight weaning was lower in the EW group ( P<. 0.05). It is possible to use CN to obtain lambing periods less than eight months in Santa Ines ewes, with the advantages of simpler management and higher lamb weaning weights. © 2013 Elsevier B.V.

Body condition score of Nellore beef cows: a heritable measure to improve the selection of reproductive and maternal traits

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of Initial Body Condition, Frame Size and Concentration of Dietary Energy on Carcass Value of Finished Steers

Yearling steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed diets containing 0.59 or 0.64 Mcal NEg per pound of diet. The value of each carcass was determined by use of the Oklahoma State University Boxed Beef Calculator. Sorting to increase hip height decreased the percentage of Choice carcasses and fat cover, increased ribeye area, and had no effect on carcass weight or yield grades 1 and 2. Sorting to decrease initial fat cover decreased carcass weight, carcass fat cover, and percentage of choice carcasses and increased the proportion of yield grades 1 and 2 carcasses. Concentration of energy in the finishing diet had no effect on carcass measurements. Increasing the percentage of yield grades 1 and 2 carcasses did not result in increased economic value of the carcasses when quality grades were lower and when there was a wide spread between Choice and Select carcasses, as occurred in 1996. With less spread between Choice and Select, as in 1997, sorting the cattle to increase yield grades 1 and 2 resulted in increased value, especially for close-trim boxed beef. The results of this study emphasize the importance of knowing how carcasses will grade before selecting a valuebased market for selling cattle.