Effect of intermittent chronic exposure to hypoxia on feeding behaviour of rats

Healthy albino male rats were exposed to a simulated high altitude (HA) equivalent to 25000 ft (7620 m) for 6 h daily, continuously for 21 days to study the feeding behaviour. The 24-h food and water intake and body weight once in 3 days were recorded. Blood samples were drawn once a week from the retro-orbital venous plexus for blood sugar analysis. All the parameters were recorded before, during and after exposure to simulated HA. The results show a decrease in 24-h food and water intake and decreased gain in body weight during hypoxic exposure, which showed a tendency to come back to control during the post-exposure period. The blood sugar reflected a state of mild hyperglycaemia during exposure to HA.     

High temperature and oxygen supplementation can mitigate the effects of hypoxia on developmental stability of bilateral traits during incubation of broiler breeder eggs

Hypoxia strongly affects embryonic development during the pre-hatch period. This study was conducted to investigate the effects of oxygen supplementation (O) and a 38.5°C high temperature (HT) at high altitude (HA, 1720 m) on morphological traits during a pre-hatch period and on relative fluctuating asymmetry (relative FA) and allometric growth during an early post-hatch period in broilers. A total of 720 eggs were obtained from a 45-week-old Ross 308 broiler breeder flock raised at sea level (2 m). The eggs were divided into six incubation condition (IC) groups and were incubated at HA. O groups were exposed to 23.5% O₂ for 1 h daily from either days 0 to 11 (O_0–11), days 12 to 21 (O_12–21) or days 18 to 21 (O_18–21) of incubation. HT groups were exposed to 38.5°C daily from either days 12 to 21 (HT_12–21) or days 18 to 21 (HT_18–21) of incubation. A control was maintained at 37.8°C and 21% O₂. The hatched chicks were raised for 6 days at HA. Embryo/chick and beak lengths and head diameter were measured during pre- and post-hatch periods. The face, middle toe and shank lengths were measured for each chick. The relative asymmetry (RA), mean RA (MRA) and allometric growth of the lengths were computed and the existence of FA was demonstrated. The IC significantly affected the embryo length, with embryos of the O_0–11 group shorter than embryos of the other O groups. Chicks were longer in the O and HT groups than those in the control, except for the O_0–11. We found significant interactions between the IC and each development period for beak length. During the post-hatch period, the head diameter of the O_0-11 was significantly smaller than that of the other groups, but not in O_12–21. The interactions among IC, age and sex were significant for the RA of the face and middle toe lengths and for MRA. All the examined bilateral traits were evaluated as allometric growth. The FA for bilateral traits was determined in both sexes. The right (R) – left (L) and IR-Ll were the lowest in females for face length and in males for shank length from the O_18–21 and in males for middle toe length from the O_0–11 and HT_18–21 groups. Therefore, the effects of factors such as HT and O₂ could mitigate the adverse effects of HA-induced hypoxia on optimal developmental stability of bilateral traits of broiler.     

Modelling expected trout ranges under current and future water temperature regimes in the Eastern Cape,South Africa

Different values have resulted in conflicts between anglers and conservation lobbies in the management of trout in South Africa. Key to the conflict is the demarcation of boundaries to areas in which brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss currently occur, or are likely to establish following stocking for angling. To provide a longer-term perspective on these areas, we developed models to link salmonid biological thermal thresholds to elevation. These, when applied spatially using a digital elevation model with a probability of occurrence model, provided the basis for estimating potentially available thermal habitat for these two cold water species. Here, we acknowledge that other variables (stocking history; river connectivity) also play a role in understanding trout distributions. Using a simple scenario of an increase in mean daily water temperatures of 2 °C, we demonstrated that both brown and rainbow trout are likely to exhibit considerable range reductions in the future. Because it is possible that these range restrictions will result in an increasing desire to introduce trout into areas above their current distribution limits for the maintenance of angling opportunities, conservation managers should prioritise these areas, with management interventions seeking to understand what will help to limit introductions.     

亚洲树轮平均敏感度分布特征及其影响因素

树轮敏感度是指示树轮对气候变化敏感程度的重要统计参数,研究大尺度树木敏感度的分布特征及其影响因素有助于理解树木生长和气候的相互关系.本文使用来自国际树轮库(ITRDB)的573条树轮宽度记录,研究亚洲树轮敏感度的分布特征及可能的影响因素.结果表明: 在干旱地区和温度较低的区域,树木的平均敏感度更高,降水对敏感度的影响强于温度.平均敏感度随海拔的上升表现出下降-上升-下降的波动变化.这种波动与降水随着海拔表现的上升-下降-上升的变化相吻合,说明海拔变化导致的降水改变可能是导致平均敏感度变化的重要因素之一.不同树种生理性状的差异导致其敏感度差异较大,祁连圆柏、西藏白皮松等阳生树种由于耐旱性而具有更高的敏感度,而阴生树种如云杉属和冷杉属则敏感度较低;老龄树可能具有更高的敏感度.     

A pharmacological investigation of Hippophae salicifolia (HS) and Hippophae rhamnoides turkestanica (HRT) against multiple stress (C-H-R): an experimental study using rat model

Hippophae salicifolia (HS) and Hippophae rhamnoides turkestanica (HRT) are abundantly found species of Hippophae in Himalayan region of India. As these plants thrive under extreme climatic conditions, it is suspected that these plants must have a unique adaptogenic property against high-altitude stress. To keeping these views in our mind, the present study was planned to evaluate the mechanism of action of aqueous extract of HS and aqueous extract of HRT against multiple stress [cold-hypoxia-restraint (C-H-R)] for their adaptogenic activity. The present study reported the adaptogenic activity of HS in facilitating tolerance to multiple stress, CHR in rats. Pre-treatment with aqueous extract of HS significantly attenuated reactive oxygen species (ROS) production, protein oxidation, and lipid peroxidation and also showed role in maintaining antioxidant status as similar to control rats. Since protein oxidation was decreased by pre-treatment of HS, protein homeostasis was also sustained by regulation of heat shock proteins (HSP70 and HSP60). Interestingly, heme oxygenase-1 (HO-1), Vascular Endothelial Growth Factor (VEGF), and nitric oxide (NO) level was also increased in HS pre-treated rats depicted its adaptogenic activity against multiple stress, CHR. Conclusively, aqueous extract of HS could use an adaptogen for high altitude-associated multiple stress (CHR).     

Biology and phenology of three leaf beetle species (Chrysomelidae) in a montane forest in southeast Brazil

The population phenology of the cassidines, Coptocycla arcuata and Omaspides trichroa, and the chrysomeline, Platyphora axillaris, was studied at Serra dos Órgãos National Park, State of Rio de Janeiro, southeast Brazil. Monthly surveys of larvae and adults were conducted between 2008 and 2011 at approximately 1000 m altitude on their respective host plants, Cordia polycephala (Boraginaceae), Ipomoea philomega (Convolvulaceae) and Solanum scuticum (Solanaceae). This is the first observation of larviparity and host record for Platyphora axillaris. Although having different life history traits, all species showed similar phenologies. They were abundant from October to March, months of high temperatures and intense rainfall, with two distinct reproductive peaks in the same season. Abundance dropped abruptly during the coldest and driest months, from May to August. Frequently none of these species were recorded during June and July. This phenological pattern is similar to other Chrysomelidae living in subtropical areas of Brazil. Temperature and rainfall appear to be the major factors influencing the fluctuation of these three species.