Stressful Dieting: Nutritional Conditions but Not Compensatory Growth Elevate Corticosterone Levels in Zebra Finch Nestlings and Fledglings

Unfavourable conditions throughout the period of parental care can severely affect growth, reproductive performance, and survival. Yet, individuals may be affected differently, depending on the developmental period during which constraints are experienced. Here we tested whether the nestling phase compared to the fledgling phase is more susceptible to nutritional stress by considering biometry, physiology, sexually selected male ornaments and survival using zebra finches (Taeniopygia guttata) as a model species. As nestlings (day 0–17) or fledglings (day 17–35), subjects were raised either on low or high quality food. A low quality diet resulted in significantly elevated baseline corticosterone titres in both nestlings and fledglings. Subjects showed substantial compensatory growth after they had experienced low quality food as nestlings but catch-up growth did neither lead to elevated baseline corticosterone titres nor did we detect long term effects on biometry, male cheek patch, or survival. The compensation for temporally unfavourable environmental conditions reflects substantial phenotypic plasticity and the results show that costs of catch-up growth were not mediated via corticosterone as a physiological correlate of allostatic load. These findings provide new insights into the mechanisms and plasticity with which animals respond to periods of constraints during development as they may occur in a mistiming of breeding

Early Fasting Is Long Lasting: Differences in Early Nutritional Conditions Reappear under Stressful Conditions in Adult Female Zebra Finches

Conditions experienced during early life can have profound effects on individual development and condition in adulthood. Differences in nutritional provisioning in birds during the first month of life can lead to differences in growth, reproductive success and survival. Yet, under natural conditions shorter periods of nutritional stress will be more prevalent. Individuals may respond differently, depending on the period of development during which nutritional stress was experienced. Such differences may surface specifically when poor environmental conditions challenge individuals again as adults. Here, we investigated long term consequences of differences in nutritional conditions experienced during different periods of early development by female zebra finches (Taeniopygia guttata) on measures of management and acquisition of body reserves. As nestlings or fledglings, subjects were raised under different nutritional conditions, a low or high quality diet. After subjects reached sexual maturity, we measured their sensitivity to periods of food restriction, their exploration and foraging behaviour as well as adult resting metabolic rate (RMR). During a short period of food restriction, subjects from the poor nutritional conditions had a higher body mass loss than those raised under qualitatively superior nutritional conditions. Moreover, subjects that were raised under poor nutritional conditions were faster to engage in exploratory and foraging behaviour. But RMR did not differ among treatments. These results reveal that early nutritional conditions affect adult exploratory behaviour, a representative personality trait, foraging and adult's physiological condition. As early nutritional conditions are reflected in adult phenotypic plasticity specifically when stressful situations reappear, the results suggest that costs for poor developmental conditions are paid when environmental conditions deteriorate

Progress in adolescent health and wellbeing: tracking 12 headline indicators for 195 countries and territories, 1990–2016

Background: Rapid demographic, epidemiological, and nutritional transitons have brought a pressing need to track progress in adolescent health. Here, we present country-level estimates of 12 headline indicators from the Lancet Commission on adolescent health and wellbeing, from 1990 to 2016. Methods: Indicators included those of health outcomes (disability-adjusted life-years [DALYs] due to communicable, maternal, and nutritional diseases; injuries; and non-communicable diseases); health risks (tobacco smoking, binge drinking, overweight, and anaemia); and social determinants of health (adolescent fertility; completion of secondary education; not in education, employment, or training [NEET]; child marriage; and demand for contraception satisfied with modern methods). We drew data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016, International Labour Organisation, household surveys, and the Barro-Lee education dataset. Findings: From 1990 to 2016, remarkable shifts in adolescent health occurred. A decrease in disease burden in many countries has been offset by population growth in countries with the poorest adolescent health profiles. Compared with 1990, an additional 250 million adolescents were living in multi-burden countries in 2016, where they face a heavy and complex burden of disease. The rapidity of nutritional transition is evident from the 324·1 million (18%) of 1·8 billion adolescents globally who were overweight or obese in 2016, an increase of 176·9 million compared with 1990, and the 430·7 million (24%) who had anaemia in 2016, an increase of 74·2 million compared with 1990. Child marriage remains common, with an estimated 66 million women aged 20–24 years married before age 18 years. Although gender-parity in secondary school completion exists globally, prevalence of NEET remains high for young women in multi-burden countries, suggesting few opportunities to enter the workforce in these settings. Interpretation: Although disease burden has fallen in many settings, demographic shifts have heightened global inequalities. Global disease burden has changed little since 1990 and the prevalence of many adolescent health risks have increased. Health, education, and legal systems have not kept pace with shifting adolescent needs and demographic changes. Gender inequity remains a powerful driver of poor adolescent health in many countries. Funding: Australian National Health and Medical Research Council, and the Bill & Melinda Gates Foundatio

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Implications of nutritional stress as nestling or fledgling on subsequent attractiveness and fecundity in zebra finches (Taeniopygia guttata)

The conditions an organism experiences during early development can have profound and long lasting effects on its subsequent behavior, attractiveness, and life history decisions. Most previous studies have exposed individuals to different conditions throughout development until nutritional independence. Yet under natural conditions, individuals may experience limitations for much shorter periods due to transient environmental fluctuations. Here, we used zebra finches (Taeniopygia guttata) in captivity to determine if conditions experienced during distinctly different early developmental phases contribute differently to male and female attractiveness and subsequent reproduction. We conducted a breeding experiment in which offspring were exposed to food regimes with (a) low quality food provided only during the nestling period, (b) low quality food provided only during the fledgling period, or (c) high quality food throughout early development. We show that despite short-term effects on biometry and physiology, there were no effects on either male or female attractiveness, as tested in two-way mate choice free-flight aviary experiments. In a subsequent breeding experiment, the offspring from the initial experiment were allowed to breed themselves. The next generation offspring from mothers raised under lower quality nutrition as either nestling or fledging were lighter at hatching compared to offspring from mothers raised under higher quality nutrition whereas paternal early nutrition had no such effects. The lack of early developmental limitations on attractiveness suggests that attractiveness traits were not affected or that birds compensated for any such effects. Furthermore, maternal trans-generational effects of dietary restrictions emphasize the importance of role of limited periods of early developmental stress in the expression of environmentally determined fitness components.</p

Nutrition and peer group composition in early adolescence: impacts on male song and female preference in zebra finches

Honarmand M, Riebel K, Naguib M. Nutrition and peer group composition in early adolescence: impacts on male song and female preference in zebra finches. Animal Behaviour. 2015;107:147-158

Figure 3

<p>Experimental setup (a) for the spatial foraging test which was conducted in an aviary (1.85×1.85×1.85 m) with four potential feeding sites. The grey areas indicate a hut which blocked the view to the feeding site unless subjects perched on the perch next to the site. The white areas in front of the hut were visible from the adjacent perch and indicate the platform in front of the hut on which the food was provided. Circles indicate the four possible positions of a food dish. During a test only one food dish was rewarded with food, the others remained empty. Drawing is not to scale. (b) The mean latency to approach the food (±SE) for subjects from the LH and the HH treatment and (c) the mean latency (±SE) until subjects fed in this test. In the LH (low-high) treatment subjects fed on a low quality seed diet until day 17 (nestling period) followed by a protein enriched high quality diet up to day 35 (fledging period). In the HH treatment (high-high) a high quality protein enriched diet was fed throughout the nestling and fledgling phase (see text for details). * p<0.05.</p

Effects of the nutritional treatments on resting metabolic rate.

<p>Mean (±SE) resting metabolic rate (RMR) for subjects from the different early nutritional treatments, LH, HL and HH. In the LH (low-high) treatment subjects fed on a low quality seed diet until day 17 (nestling period) followed by a protein enriched high quality diet up to day 35 (fledging period). Subjects in the HL (high-low) treatment experienced the nutritional diets vice versa. In the HH treatment (high-high) a high quality protein enriched diet was fed throughout the nestling and fledgling phase (see text for details).</p