Oxidative status: A general but overlooked indicator of welfare across animal species?

Assessment of Oxidative Stress and Biometric Data in a Captive Colony of Hamadryas Baboons (Papio hamadryas Linnaeus, 1758) at the Ravenna Zoo Safari (Italy)

This study evaluates the health of a captive colony of Hamadryas baboons at Ravenna Zoo Safari (Italy), focusing on oxidative stress markers and biometric data. Forty-eight individuals were assessed during routine veterinary procedures: males underwent vasectomy, and females were checked for pregnancy. Biometric data collected included body weight, body length, and genital measurements in males, while females were evaluated for reproductive status. Oxidative stress was measured using two tests that assess both harmful pro-oxidant levels and the body's antioxidant defenses. Results showed no significant differences in oxidative stress levels between sexes, although males and females differed in body weight. Pregnant and postpartum females exhibited higher oxidative stress, likely due to the metabolic and hormonal demands of reproduction. This supports the idea that reproductive activity increases the production of reactive oxygen species, requiring stronger antioxidant responses. In males, correlations between body weight and genital measurements suggest these could help estimate age in the absence of birth records. No link was found between oxidative stress and body weight, indicating limited age-related effects on these markers. Overall, the study highlights the importance of monitoring oxidative stress in captive primates to better understand the effects of reproduction and aging, and to improve welfare and management practices.

Review: Exploring correctness, usefulness, and feasibility of potential physiological operational welfare indicators for farmed insects to establish research priorities

While insects are already the largest group of terrestrial food and feed livestock animals in terms of absolute number of individuals, the insect farming industry is expected to continue growing rapidly in order to meet the nutritional demands of the human population during the 21st century. Accordingly, consumers, producers, legislators, and industry-adjacent researchers have expressed interest in further research and assessment of farmed insect welfare. Operational indicators of animal welfare are those that can be used to putatively assess the welfare of animals in the absence of true indicators of affective state (e.g., valenced/emotional state) and are commonly used for farmed vertebrate livestock species; however, significant behavioral and physiological differences between vertebrates and insects means these indicators must be examined for their correctness, usefulness, and feasibility prior to use with insect livestock. The most valuable operational welfare indicators would (1) correctly correspond to the insect's putative welfare state; (2) provide useful information about what is affecting the insect's welfare; and (3) be feasible for deployment at a large scale on farms. As there are many possible indicators that could be further researched in insects, evaluating the likely correctness, feasibility, and usefulness of these indicators in insects will allow researchers to prioritize which indicators to investigate first for use on farms. Thus, in this review, we explore whether physiological or somatic indicators of farmed vertebrate welfare, including whole-body, immune, neurobiological, and respiratory/cardiac indicators, may be correct, feasible, and useful for assessing farmed insect welfare. We review insect physiological systems, as well as any existing, welfare-relevant data from farmed or closely related insects. We end by proposing a priority list for physiological, operational welfare indicators that are most likely to correctly, usefully, and feasibly assess farmed insect welfare, which may guide indicator validation research priorities for insect welfare scientists.

Harnessing the gut microbiome: a potential biomarker for wild animal welfare

The welfare of wild animal populations is critically important to conservation, with profound implications for ecosystem health, biodiversity, and zoonotic disease transmission. Animal welfare is typically defined as the accumulated affective mental state of an animal over a particular time period. However, the assessment of animal welfare in the wild poses unique challenges, primarily due to the lack of universally applicable biomarkers. This perspective explores the potential role of the gut microbiome, a dynamic and non-invasive biomarker, as a novel avenue for evaluating animal welfare in wild animals. The gut microbiome, through interactions with the host's physiology, behavior, and cognition, offers a promising opportunity to gain insights into the well-being of animals. In this synthesis, we discuss the distinction between fitness and welfare, the complexities of assessing welfare in wild populations, and the linkages between the gut microbiome and aspects of animal welfare such as behavior and cognition. We lastly elucidate how the gut microbiome could serve as a valuable tool for wildlife managers, with the potential to serve as a non-invasive yet informative window into the welfare of wild animals. As this nascent field evolves, it presents unique opportunities to enhance our understanding of the well-being of wild animals and to contribute to the preservation of ecosystems, biodiversity, and human health.