Sex differences in basal hypothalamic anorectic and orexigenic gene expression and the effect of quantitative and qualitative food restriction

Abstract Background Research into energy balance and growth has infrequently considered genetic sex, yet there is sexual dimorphism for growth across the animal kingdom. We test the hypothesis that in the chicken, there is a sex difference in arcuate nucleus neuropeptide gene expression, since previous research indicates hypothalamic AGRP expression is correlated with growth potential and that males grow faster than females. Because growth has been heavily selected in some chicken lines, food restriction is necessary to improve reproductive performance and welfare, but this increases hunger. Dietary dilution has been proposed to ameliorate this undesirable effect. We aimed to distinguish the effects of gut fullness from nutritional feedback on hypothalamic gene expression and its interaction with sex. Methods Twelve-week-old male and female fast-growing chickens were either released from restriction and fed ad libitum or a restricted diet plus 15% w/w ispaghula husk, a non-nutritive bulking agent, for 2 days. A control group remained on quantitative restriction. Hypothalamic arcuate nucleus neuropeptides were measured using real-time PCR. To confirm observed sex differences, the experiment was repeated using only ad libitum and restricted fed fast-growing chickens and in a genetically distinct breed of ad libitum fed male and female chickens. Linear mixed models (Genstat 18) were used for statistical analysis with transformation where appropriate. Results There were pronounced sex differences: expression of the orexigenic genes AGRP (P < 0.001) and NPY (P < 0.002) was higher in males of the fast-growing strain. In genetically distinct chickens, males had higher AGRP mRNA (P = 0.002) expression than females, suggesting sex difference was not restricted to a fast-growing strain. AGRP (P < 0.001) expression was significantly decreased in ad libitum fed birds but was high and indistinguishable between birds on a quantitative versus qualitative restricted diet. Inversely, gene expression of the anorectic genes POMC and CART was significantly higher in ad libitum fed birds but no consistent sex differences were observed. Conclusion Expression of orexigenic peptides in the avian hypothalamus are significantly different between sexes. This could be useful starting point of investigating further if AGRP is an indicator of growth potential. Results also demonstrate that gut fill alone does not reduce orexigenic gene expression

Visual Laterality of Calf–Mother Interactions in Wild Whales

Behavioral laterality is known for a variety of vertebrate and invertebrate animals. Laterality in social interactions has been described for a wide range of species including humans. Although evidence and theoretical predictions indicate that in social species the degree of population level laterality is greater than in solitary ones, the origin of these unilateral biases is not fully understood. It is especially poorly studied in the wild animals. Little is known about the role, which laterality in social interactions plays in natural populations. A number of brain characteristics make cetaceans most suitable for investigation of lateralization in social contacts.) in the greatest breeding aggregation in the White Sea. Here we show that young calves (in 29 individually identified and in over a hundred of individually not recognized mother-calf pairs) swim and rest significantly longer on a mother's right side. Further observations along with the data from other cetaceans indicate that found laterality is a result of the calves' preference to observe their mothers with the left eye, i.e., to analyze the information on a socially significant object in the right brain hemisphere.Data from our and previous work on cetacean laterality suggest that basic brain lateralizations are expressed in the same way in cetaceans and other vertebrates. While the information on social partners and novel objects is analyzed in the right brain hemisphere, the control of feeding behavior is performed by the left brain hemisphere. Continuous unilateral visual contacts of calves to mothers with the left eye may influence social development of the young by activation of the contralateral (right) brain hemisphere, indicating a possible mechanism on how behavioral lateralization may influence species life and welfare. This hypothesis is supported by evidence from other vertebrates

The two hemispheres of the avian brain: their differing roles in perceptual processing and the expression of behavior

The hemispheres of the avian brain are specialized to carry out different functions. Since each eye sends its input mainly to the contralateral hemisphere, birds respond differently to stimuli seen with the left eye than they do to stimuli seen with the right eye. The right hemisphere attends to novel stimuli, which easily distract it from ongoing functions. It assumes control in emergency or stressful conditions. The left hemisphere attends to learnt categories and controls behavior in routine, non-stressful situations. This division of function extends to processing of auditory, olfactory and even magnetic stimuli. Evidence for this comes from a number of avian species, and has been shown in both laboratory and field tests. Knowledge of these specializations is relevant to understanding the behavior of birds in the wild since birds respond in different ways to stimuli on their left and right sides (e.g. preferential response to predators and conspecific on the left side and to prey on the right side) and they choose to view different stimuli with the left or right eye. Individual differences in the strength of visual lateralization are determined by exposure of the embryo to light, versus incubation in the dark, and by the levels of steroid hormones in ovo. The importance of these influences on lateralization is discussed in terms of behavior in the natural habitat. The potential importance of hemispheric dominance in the welfare of birds is also considered

The long road to developing agromining/phytomining

The concept of phytomining is a natural extension of botanical prospecting and the study of metal biochemistry and biogeography of metal hyperaccumulator plants. Some elements may be phyto-extracted to remediate soils, but the recovered biomass would have little economic value (Cd, As, etc.) and disposal of the biomass would be a cost. A few elements may have sufficient economic value in phytomining biomass to support commercial practice (Ni, Co, Au). The development of phytomining requires (1) selection of high-biomass hyperaccumulator plant species; (2) evaluation of genetic diversity and breeding of improved strains with higher yields of the phytoextracted element; (3) development of agronomic practices to maximize economic return; and (4) development of methods to recover the phytomined element from the plant biomass. Plant species and methods for phytomining of soil Ni have been demonstrated for several species and locations (temperate and tropical climates). Production of Ni metal in an electric arc furnace smelter, and of Ni(NH4) 2SO4 using a hydrometallurgical method, have been demonstrated. Full commercial phytomining of Ni is beginning in Albania using Alyssum murale, and major trials in Malaysia are underway using Phyllanthus securinegioides. Variable prices of commodity metals add confusion to the development of commercial phytomining

Phytoremediation of soils contaminated with heavy metals: techniques and strategies

Environmental pollution by heavy metals and metalloids has become a severe problem worldwide, as soils became increasingly contaminated, posing a threat to ecosystems and ultimately to human health. The decision to remediate a soil depends on the present and future value of the soil, the cost of remediation, the risk posed by the soil, and the perception of that risk by the population and decision-makers. Traditional technologies to remediate soils usually rely on excavation of the contaminated soil, often disposed of as a hazardous waste with or without a previous treatment. The use of plants to remove or immobilize toxic elements has arisen as a very promising alternative to conventional technologies. The use of plants to remediate soils derived from the observation of wild species found in specific environments, evolved to the use of fast growing crops, and later on led to the development of genetically-modified plants. Phytotechnologies include a wide range of technologies that can be applied to remediate soils through stabilization, volatilization, accumulation and sequestration of toxic metals. In this chapter we describe the impacts of heavy metals in plants and the most important phytotechnologies available to remediate soil and substrates