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Initial Body Mass (initial + body_mass)
Selected AbstractsDose-dependent uptake, elimination, and toxicity of monosodium methanearsonate in adult zebra finches (Taeniopygia guttata)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2008Courtney A. Albert Abstract Monosodium methanearsonate (MSMA), an arsenic-based pesticide, has been used for the past 10 years in attempts to suppress mountain pine beetle (Dendroctonus ponderosae) outbreaks in British Columbia, Canada. Previous studies have shown that cavity nesting forest birds such as woodpeckers forage and breed in MSMA treated pine stands. Here we examined the effects of MSMA in the laboratory using the zebra finch (Taeniopygia guttata), with the objective to examine tissue distribution and sublethal toxic effects in a model avian species. Zebra finches were exposed to this pesticide at doses similar to those found in bark beetle samples from MSMA stands of trees treated in the southern interior of British Columbia (8, 24, and 72 ,g/g/d and a control group). Results showed high excretion (>90%) of arsenic in all dose groups, as well as dose-dependent trends in accumulation of arsenic in the blood (p < 0.001) and specific tissues. Monomethylarsonic acid, MMA (V), was the predominant form of arsenic in the blood plasma. Dimethylarsinic acid was the major form of arsenic found in the liver (83%) and kidney (61%) tissues. The brain tissue contained primarily the MMA (V) form (57%). Significant weight loss occurred in the two highest dose groups (p < 0.05). Birds in the highest dose group lost up to 15% of initial body mass. [source] When heavier birds lose more mass during breeding: statistical artefact or biologically meaningful?JOURNAL OF AVIAN BIOLOGY, Issue 2 2000Sabine G. Gebhardt-HenrichArticle first published online: 30 OCT 200 Several studies on mass loss during breeding in female birds have shown a significant correlation between initial body mass and subsequent loss of body mass. The significant positive regression coefficient of mass loss on initial mass was interpreted as evidence for a greater mass loss of initially heavier birds. However, the positive correlation between mass loss and initial mass arises automatically even when initial and final body masses are uncorrelated and has no necessary biological meaning. This is shown analytically here. In general, a spurious correlation arises when one variable (e.g. mass loss) is part of another variable (e.g. initial mass) and then regressed on it. [source] Growth in pups of the subantarctic fur seal (Arctocephalus tropicalis) on Amsterdam IslandJOURNAL OF ZOOLOGY, Issue 3 2000C. Guinet Abstract Growth in body mass in pups of the subantarctic fur seal Arctocephalus tropicalis was studied at Amsterdam Island, southern Indian Ocean during the rearing period between December 1995 and August 1996. We examined the change in the rates of mass gain and mass loss with pup age to explain the overall change in mass throughout the rearing period, when mothers alternate foraging trips at sea and attendance periods ashore. In the absence of their mothers, pups fast and lose mass. During the maternal attendance period ashore pups suck and gain mass. There was no significant difference in the rate of growth in mass between male and female pups. The rate of loss in mass during a fasting event was positively related to the initial body mass but negatively related to the age and duration of the fast of the pup. The rate of mass loss was best related to pup age by a quadratic relationship. The rate of mass loss increased until pups were 120 days old and then decreased until the end of the study period. The rate of gain in mass following a maternal foraging trip was positively related to the initial pup mass but negatively related to the foraging trip duration, and we found that the rate of mass gain decreased linearly with the age of the pup. The concomitant decrease in the rate of mass loss and mass gain for pups > 120 days old allowed pups to maintain a positive growth until they were 220 days old. After 220 days of age the rate of mass loss exceeded the rate of mass gain and the pups start to lose mass until weaning. [source] Infant weight-for-length is positively associated with subsequent linear growth across four different populationsMATERNAL & CHILD NUTRITION, Issue 1 2005Kathryn G. Dewey phd Abstract Several studies have documented that length gain often lags behind weight gain during infancy and early childhood, suggesting that linear growth is partly regulated by initial body mass or fatness. To investigate this hypothesis, we analysed data from four longitudinal studies on growth of infants in the first 12 months: (1) U.S. breast-fed and formula-fed infants (n = 89); (2) breast-fed infants in Ghana (n = 190); (3) normal birthweight, breast-fed infants in Honduras (n = 108); and (4) term, low-birthweight breast-fed infants in Honduras (n = 119). The dependent variable was length gain during each 3-month interval (1, 4, 2,5, 3,6, 4,7, 5,8, 6,9, 7,10, 8,11 and 9,12 months). Three main independent variables were examined: initial weight-for-length z-score (W/L), weight change during the prior 3 months, and initial skinfold thickness. Controlling for maternal height, infant sex, and initial length-for-age z-score, length gain was positively correlated with initial W/L and prior weight change during all age intervals and with initial skinfold thickness at 3 and 4 months (r = 0.15,0.36; P < 0.01). There was no evidence of a threshold effect. These associations were evident in all four populations, in both boys and girls, and in breast-fed and formula-fed infants. The consistency of this relationship across studies supports the hypothesis that linear growth is partly regulated by initial body mass or fatness in infants. [source] Osmoregulation, growth and moulting cycles of the giant freshwater prawn (Macrobrachium rosenbergii) at different salinitiesAQUACULTURE RESEARCH, Issue 9 2010Do Thi Thanh Huong Abstract The giant freshwater prawn, Macrobrachium rosenbergii, is a species with a high commercial value in aquaculture. Two experiments were performed to determine the effects of salinities on the osmoregulation, growth and molting cycles of M. rosenbergii during growout. The first experiment was designed to determine whether these animals are capable of adapting to the changes in salinity seen in salinity intrusions in tropical deltas, with an incremental increase in salinity of 3, per day from 0, to 30, Haemolymph osmolality was rapidly regulated up to salinities of 15, , whereas animals conformed at higher salinities. The second experiment determined the growth, moulting cycle, osmolality, muscle water content and mortality during a 4-month experiment at 0,, 15, or 25, salinity. The weight gains in 0, and 15, were not significantly different and were comparable to the growth rates achieved in production farms with body mass increases of 2.6 and 2.3-fold their initial body mass, respectively, after 4 months. The 25, group suffered from low growth, high mortality and a significantly lower moulting frequency. These data show that this species can be reared in brackish water up to 15,, allowing for farming in the large areas impacted by salt water intrusions in tropical deltas. [source] | ||||||||||