22421 research outputs found
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Vulnerability of marine megafauna to global at‐sea anthropogenic threats
Full text linkMarine megafauna species are affected by a wide range of anthropogenic threats. To evaluate the risk of such threats, species’ vulnerability to each threat must first be determined. We build on the existing threats classification scheme and ranking system of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species by assessing the vulnerability of 256 marine megafauna species to 23 at‐sea threats. The threats we considered included individual fishing gear types, climate‐change‐related subthreats not previously assessed, and threats associated with coastal impacts and maritime disturbances. Our ratings resulted in 70 species having high vulnerability (v > 0.778 out of 1) to at least 1 threat, primarily drifting longlines, temperature extremes, or fixed gear. These 3 threats were also considered to have the most severe effects (i.e., steepest population declines). Overall, temperature extremes and plastics and other solid waste were rated as affecting the largest proportion of populations. Penguins, pinnipeds, and polar bears had the highest vulnerability to temperature extremes. Bony fishes had the highest vulnerability to drifting longlines and plastics and other solid waste; pelagic cetaceans to 4 maritime disturbance threats; elasmobranchs to 5 fishing threats; and flying birds to drifting longlines and 2 maritime disturbance threats. Sirenians and turtles had the highest vulnerability to at least one threat from all 4 categories. Despite not necessarily having severe effects for most taxonomic groups, temperature extremes were rated among the top threats for all taxa except bony fishes. The vulnerability scores we provide are an important first step in estimating the risk of threats to marine megafauna. Importantly, they help differentiate scope from severity, which is key to identifying threats that should be prioritized for mitigation
Alginate encapsulation enhanced the gastrointestinal stability and bactericidal efficacy of an optimized Salmonella phage cocktail for oral delivery in poultry feed
Full text linkSalmonella is a leading cause of gastroenteritis, and it is transmitted via contaminated water and food sources, especially poultry products. Many serovars are resistant to frontline antibiotics, necessitating the need for alternative treatment strategies. Bacteriophage (phage) therapy offers a promising alternative to antibiotics for Salmonella infection control in poultry, however, oral delivery is limited by the highly acidic gastric environment. Thus, this study aimed to optimize a cocktail of encapsulated phages to preserve and enhance their shelf-life, viability, target release and activity in the digestive tract of chickens. The phage cocktail, consisting of three strictly lytic Salmonella phages (ST-W23, SE-W112, and ST-W139) isolated from wastewater, exhibited a broad host range, lysing ∼83% (107/129) of 25 important Salmonella serovars identified from chicken farms. To enhance stability in acidic conditions, the phage cocktail was encapsulated in alginate–CaCO3 jelly beads. Under simulated gastric conditions, a single application of the encapsulated cocktail reduced S. Typhimurium growth below detectable limits within 3 h post-treatment and inhibited further regrowth for 24 h. Furthermore, the encapsulated phages maintained high viability for at least a month at room temperature, eliminating the need for cold storage logistics. This study demonstrates an effective phage encapsulation technique for optimal phage storage, oral administration and therapeutic efficacy to control intestinal Salmonella in poultry and protect public health. Further work will focus on upscaling phage production and testing in poultry farms
Short-term stability over time and across situations of behavioural traits in gestating and lactating sows
Full text linkPersonality consists of the set of traits which show stable individual differences in behaviour over time and across contexts in a species. Personality has been previously studied in pigs, however few studies have focussed on adult females and on both the gestating and lactating phases of their reproductive cycle. The aim of this work was to identify candidate personality traits in breeding females, by assessing temporal stability and associations between situations. Adult female pigs (Sus scrofa) ranging from parity one to seven underwent a series of repeated tests and observations during late gestation (70–110 days after service) and during lactation (1–30 days after farrowing). In gestation, their response to a human in the home pen (n = 55, median 2 repeated tests per individual, ranging from 1 to 4) and social behaviour at feeding (n = 52, median 2 tests, 1–4) were assessed. In lactation their response to a dummy hand (n = 66, median 2 tests, 1–4) and lying down behaviour (n = 68, median 2 tests, 1–6) were recorded as indicators of maternal defence and maternal care. Out of the twelve variables measured in these four different situations, five were consistent over repeated tests at different times (i.e. the posterior distribution of their repeatability excluded values less than 0.01): dominance rank, number of attacks, and number of avoidances during feeding, number of vocalisations when exposed to a dummy hand, and probability of vocalising before lying down. We found correlations with an absolute value higher than 0.30 between number of attacks and number of avoidances during feeding (r = -0.33), number of attacks and number of vocalisations when exposed to the dummy hand (r = -0.52), and between the latter and probability of vocalising before lying down during lactation (r = 0.46). Our results suggest that social behaviour at feeding and acoustic signalling in different contexts are stable traits in adult female pigs. The estimated correlations between the traits might also indicate the presence of a proactive behavioural syndrome
Distress calls as social stressors affecting chicken welfare
Full text linkSocial signals about current environmental risks can shape development in young animals. Distress calls made by young chickens (Gallus gallus domesticus) may also encode affective state, with high arousal, potentially ‘anxiety-like’ state characterized by continuous calling, and learned helplessness or potentially ‘depression-like’ state by a more intermittent pattern. During early life (age 4–7 days), we played chicks artificial stimuli mimicking these two call patterns. Growth effects suggest caller affective state can modulate this social signal: chicks exposed to bouts of ‘Continuous’ calls grew faster and were heavier by late commercial life (day 43) than Controls. In contrast, chicks exposed to ‘Intermittent’ calling showed slow, then compensatory, growth. A third experimental treatment with similar ‘noisiness’ to distress calls did not influence growth. Responses to a late-life social isolation trial suggested lasting impacts on stressor perception or resilience. Comb temperature elevation during isolation, indicating acute stress, was greatest in the Continuous group. Call rate decline during isolation, potentially indicating a tendency towards learned helplessness, was steep in all three experimental treatments; hence, noise-related disturbance from vocalizations may also shape development. Distress calls are consequently an important consideration in farms, where young are raised at high density and one individual is heard by many
Integrative multi-omics analysis of dietary fibre-induced modulations in the composition and function of chicken caecal microbiota
Full text linkThe sustainability of poultry farming faces significant challenges due to rising feed costs and competition with human food sources. Dietary fibre offers a promising, cost -effective alternative due to its beneficial impact on gut health. We utilised a multi-omics approach to understand the influence of soluble inulin and insoluble cellulose dietary fibres on the composition and function of caecal microbiota in broilers. High inulin supplementation (4%) significantly altered caecal microbial composition and promoted broader microbial metabolic adaptations, indicating a strong fermentative response to this soluble fibre source. In contrast, high cellulose (4%) had a minimal impact, reflecting its limited fermentability and structural complexity. These findings provide valuable insights into how different fibre types and quantities shape gut microbial communities and their functional potential. A deeper understanding of these interactions will aid in formulating targeted dietary strategies to optimise gut health, nutrient utilisation, and overall poultry performance
Assessing smallholder fish farmers’ awareness, motivation and attitude towards the environmental impact of aquaculture
Full text linkThis study examines how smallholder fish farmers perceive and respond to the environmental impacts of aquaculture, since their awareness, motivations and attitudes shape adoption of sustainable practices. Surveying 125 Nigerian fish farmers as a case example, the results show high environmental consciousness, with 93.7% recognizing the importance of sustainability. Water pollution, excessive chemical use and resource overexploitation are viewed as the main risks of unsustainable farming. Most farmers (78.6%) adopt one or more practices, particularly wastewater treatment and improved feed management. Adoption intensity varied substantially among regular adopters, with nearly half implementing three environmental practices and approximately one quarter adopting four or more practices. Adoption is motivated by sustainability beliefs, cost savings and market demand. Three farmer types emerge: sustainability-oriented, economically motivated and reputation-conscious. Farmers with broader environmental risk awareness adopt significantly more sustainable practices than those with limited perception (p < 0.001). The number of motivational factors does not influence adoption intensity (F(5, 119) = 0.70, p = 0.629). To promote sustainable fish farming, multi-dimensional support programs that integrate economic incentives with environmental values are most effective.</p
The E205D mutation in CYP6P3 drives pyrethroid insecticide resistance in the African malaria mosquito vector Anopheles gambiae
No full textDeciphering the molecular drivers of insecticide resistance is paramount to extending the effectiveness of malaria vector control tools. Here, we demonstrate that a P450 haplotype spanning a Glu205→Asp (E205D) amino acid point mutation in the CYP6P3 gene drives pyrethroid insecticide resistance in the mosquito malaria vector Anopheles gambiae. Pooled whole-genome DNA sequencing data from A. gambiae mosquitoes detected a major P450-linked locus (CYP6 haplotype) on chromosome 2R adjacent to the locus encoding a sodium channel. In vitro metabolism assays with recombinantly expressed CYP6P3 protein revealed that the catalytic efficiency of the 205D variant for the pyrethroid insecticide permethrin was 3.7 times higher than that of the E205 variant. Similar findings were made for the related insecticide α-cypermethrin. Overexpression of the 205D variant in transgenic flies conferred higher resistance to pyrethroids compared with flies expressing the susceptible E205 variant. A DNA-based assay confirmed that the CYP6P3-E205D variant correlates with pyrethroid resistance in field mosquito populations [odds ratio (OR): 26.4; P < 0.0001] and reduces the efficacy of pyrethroid-only long-lasting insecticide bed nets. The homozygous resistance genotype of A. gambiae exhibited higher survival after exposure to the PermaNet 3.0 bed net compared with the susceptible SS genotype (OR: 6.1; P = 0.011). Furthermore, the CYP6P3-E205D variant together with the kdr target-site resistance mechanism exacerbated the loss of bed net efficacy. The 205D variant is predominant in West and Central Africa but less abundant or absent in East and South Africa, with signs of introgression with Anopheles coluzzii in Ghana.</p
Juvenile Gadoid Distributions Are Driven by Patch Boundaries and Habitat Combinations
Full text linkFish nursery areas need to be determined at the appropriate spatial scale with an understanding of how juvenile fish are distributed across combinations and arrangements of habitat types within seascapes. A seascape approach allows the influence of seabed type, patch sizes, boundaries, and habitat combinations on species distributions to be understood. This study investigated the influence of seascape ecology and species co‐occurrence patterns on the distribution of three juvenile gadoids, Atlantic cod ( Gadus morhua ), haddock ( Melanogrammus aeglefinus ), and whiting ( Merlangius merlangus ), while also accounting for the interactions between species as latent variables. We used 757 stereo baited remote underwater video (SBRUV) deployments between 2021 and 2023 across two sea lochs and adjacent bays on the north and west coasts of Scotland to gather relative abundance data. A joint species distribution model was used to determine the seascape drivers of 10 fish species as well as using an unobserved random variable to understand how species co‐occurrences influence individual species distributions. Atlantic cod, haddock, and whiting distributions were driven by distinct ecological factors yet had limited areas of overlap. Atlantic cod and haddock were most abundant in areas with a diverse mix of habitats. However, whiting were most abundant in areas with lower habitat diversity. Consistently higher relative abundance of all species near habitat patch boundaries indicates that edge effects and access to multiple habitat types are critical determinants of nursery habitat. Despite their distinct distributions explained by environmental variables, species‐to‐species co‐occurrence patterns were very similar across the three species. This may be indicative of similar ecological roles and biological interactions or similar response to an unrecorded variable. The inclusion of how species respond to seascape structures is valuable because it gives a greater level of understanding of what juvenile fish need in nursery areas at the relevant spatial scale
Juvenile Gadoid Distributions Are Driven by Patch Boundaries and Habitat Combinations
Full text linkFish nursery areas need to be determined at the appropriate spatial scale with an understanding of how juvenile fish are distributed across combinations and arrangements of habitat types within seascapes. A seascape approach allows the influence of seabed type, patch sizes, boundaries, and habitat combinations on species distributions to be understood. This study investigated the influence of seascape ecology and species co‐occurrence patterns on the distribution of three juvenile gadoids, Atlantic cod ( Gadus morhua ), haddock ( Melanogrammus aeglefinus ), and whiting ( Merlangius merlangus ), while also accounting for the interactions between species as latent variables. We used 757 stereo baited remote underwater video (SBRUV) deployments between 2021 and 2023 across two sea lochs and adjacent bays on the north and west coasts of Scotland to gather relative abundance data. A joint species distribution model was used to determine the seascape drivers of 10 fish species as well as using an unobserved random variable to understand how species co‐occurrences influence individual species distributions. Atlantic cod, haddock, and whiting distributions were driven by distinct ecological factors yet had limited areas of overlap. Atlantic cod and haddock were most abundant in areas with a diverse mix of habitats. However, whiting were most abundant in areas with lower habitat diversity. Consistently higher relative abundance of all species near habitat patch boundaries indicates that edge effects and access to multiple habitat types are critical determinants of nursery habitat. Despite their distinct distributions explained by environmental variables, species‐to‐species co‐occurrence patterns were very similar across the three species. This may be indicative of similar ecological roles and biological interactions or similar response to an unrecorded variable. The inclusion of how species respond to seascape structures is valuable because it gives a greater level of understanding of what juvenile fish need in nursery areas at the relevant spatial scale
A genetic analysis of the causes of lamb mortality determined by an on-farm postmortem procedure
Full text linkLamb mortality is a major challenge in sheep production with significant implications for animal welfare and farm profitability. This study investigated the causes of lamb mortality within the first three days of life in a lowland outdoor lambing flock in the Scottish Borders, UK, over three lambing seasons (2021−2023). Dead lambs were collected from the pastures during checking rounds three times a day, and simple on-farm postmortems were conducted once a day. A total of 468 lamb postmortem examinations were conducted to classify the most likely cause of death as dystocia, starvation/mismothering/exposure (SME), stillbirth, other, or unknown causes. Overall mortality to three days of age was 12 %, with SME (28 %) and stillbirth (27 %) the most common causes, followed by dystocia (13 %). Single and triplet born lambs (p < 0.01) were most likely to die from dystocia compared to other litter sizes and the risk of death from SME increased with litter size (p < 0.01). Direct lamb heritability estimates for death by dystocia and stillbirth were moderate (0.31 and 0.27, respectively), indicating potential for improvement via genetic selection. However, heritability for SME was not significant, highlighting the increased influence of environmental factors for this cause of lamb death. The findings demonstrate that the use of simple postmortems could be used to increase the accuracy of selection for lamb survival in breeding programmes, through the integration of breeding values for specific causes of death. This would be most applicable in well-recorded nucleus flocks that are well connected to the rest of the breeding programme.</p