Animals

14 pages, 522 KB

Open AccessHypothesis

Lymphoplasmacytic Gastritis in Cheetahs Under Human Care: A Bile Acid-Driven Gastroenteropathy Arising from Disrupted Feeding Ecology

by Adrian S. W. Tordiffe

Animals 2026, 16(10), 1494; https://doi.org/10.3390/ani16101494 (registering DOI) - 13 May 2026

Abstract

Lymphoplasmacytic gastritis (LPG) is one of the most prevalent chronic diseases affecting cheetahs (Acinonyx jubatus) under human care, yet its underlying cause remains unresolved. Gastric inflammation occurs in the majority of adult captive cheetahs but is uncommon in free-ranging populations, suggesting [...] Read more.

Lymphoplasmacytic gastritis (LPG) is one of the most prevalent chronic diseases affecting cheetahs (Acinonyx jubatus) under human care, yet its underlying cause remains unresolved. Gastric inflammation occurs in the majority of adult captive cheetahs but is uncommon in free-ranging populations, suggesting that management-related factors contribute to disease pathogenesis. This review proposes that LPG represents a bile acid-driven gastroenteropathy arising from disruption of the natural feeding ecology of the cheetah. In free-ranging systems, cheetahs consume large episodic meals separated by prolonged fasting intervals and ingest whole-prey containing substantial connective tissue and collagen. In captivity, feeding patterns are typically characterized by smaller, more frequent meals and diets dominated by lean skeletal muscle with reduced structural complexity. I hypothesize that this mismatch alters gastric emptying kinetics, disrupts coordinated pancreatic and biliary secretion, and destabilizes fat digestion. Inefficient lipolysis may impair micelle formation and promote bile acid mislocalization within the gastrointestinal tract, increasing mucosal exposure to hydrophobic bile acids capable of inducing chemical epithelial injury. Within this framework, lymphoplasmacytic gastritis is interpreted as a secondary inflammatory reaction to chronic bile acid-mediated mucosal stress rather than a primary immune-mediated disorder. The model also provides a mechanistic explanation for the frequent coexistence of gastritis with fat and protein maldigestion in captive cheetahs. Differential responses to antimicrobial therapy, glucocorticoids, sulfasalazine, pancreatic enzyme supplementation, and bile acid-modifying agents are broadly consistent with this proposed mechanism. Recognition of LPG as a physiologically driven gastroenteropathy has important implications for management, emphasizing restoration of feast–fast feeding patterns, inclusion of collagen-rich carcass components, and targeted modulation of bile acid composition and signaling. Full article

(This article belongs to the Section Zoo Animals)

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24 pages, 8702 KB

Open AccessArticle

UST-YOLO11Pose-TRM: An Attention-Enhanced Keypoint Detection and Transformer Regression Framework for Yak Body Measurement

by Hua Li, Jinghan Cai, Tonghai Liu, Yapeng Xiao, Changran Liu and Can Zhou

Animals 2026, 16(10), 1493; https://doi.org/10.3390/ani16101493 (registering DOI) - 13 May 2026

Abstract

Yak (Bos grunniens) is a vital livestock resource on the Qinghai–Tibet Plateau, and its body measurement parameters play a crucial role in growth and development assessment, health monitoring, and breeding improvement. To overcome the limitations of traditional manual measurements—such as low efficiency, unstable [...] Read more.

Yak (Bos grunniens) is a vital livestock resource on the Qinghai–Tibet Plateau, and its body measurement parameters play a crucial role in growth and development assessment, health monitoring, and breeding improvement. To overcome the limitations of traditional manual measurements—such as low efficiency, unstable accuracy, and the tendency to induce animal stress—this study proposes an intelligent yak body measurement prediction method that integrates keypoint detection with regression modeling, termed UST-YOLO11Pose-TRM. Within the YOLO11-Pose framework, three attention mechanisms—UIB, SENetV2, and TripleAttention—are incorporated to construct a lightweight yet high-precision keypoint detection model, UST-YOLO11Pose, thereby enhancing channel feature representation, global contextual modeling, and spatial dependency perception. Meanwhile, a Transformer-based regression model is designed, leveraging multi-head self-attention to characterize global geometric relationships among keypoints and to achieve accurate prediction of key body measurement parameters, including body length, body height, oblique body length, chest girth, and cannon circumference. Experimental results demonstrate that UST-YOLO11Pose achieves an mAP of 0.958, a Precision of 0.967, and a Recall of 0.955 in keypoint detection tasks, significantly outperforming both same-series and cross-series comparative models with a parameter size of only 10.06 MB. In the body measurement regression task, the Transformer-based regression model attains an RMSE of 0.185, an MAE of 0.122, an MAPE of 2.3%, and a coefficient of determination (R²) of 0.962 on the test set, indicating excellent predictive accuracy and robust fitting stability. In summary, UST-YOLO11Pose-TRM enables accurate, efficient, non-contact yak body measurement, showing strong potential for smart pasture development and precision livestock management. Full article

(This article belongs to the Section Cattle)

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19 pages, 3863 KB

Open AccessArticle

The Involvement of the PI3K/AKT Pathway in Zn Alleviation of Heat Stress-Induced Damage to Broiler Jejunal Organoids

by Weizhen Song, Weiyun Zhang, Xi Lin, Hsiao-Ching Liu, Jack Odle, Miles Todd See, Shengchen Wang, Xiaoyan Cui, Chuanlong Wang, Liyang Zhang and Xugang Luo

Animals 2026, 16(10), 1492; https://doi.org/10.3390/ani16101492 (registering DOI) - 13 May 2026

Abstract

The direct involvement of the phosphatidylinositol 3-kinase (PI3K)/serine threonine kinase (AKT) signaling pathway in the alleviation of the heat stress (HS)-induced damage to the integrity and barrier function of broiler jejunal organoids (JOs) by supplemental zinc (Zn) has not been confirmed. To verify [...] Read more.

The direct involvement of the phosphatidylinositol 3-kinase (PI3K)/serine threonine kinase (AKT) signaling pathway in the alleviation of the heat stress (HS)-induced damage to the integrity and barrier function of broiler jejunal organoids (JOs) by supplemental zinc (Zn) has not been confirmed. To verify it, two experiments were conducted in the present study. In experiment 1, the optimal concentrations of PI3K/AKT inhibitor (PI3K-IN-1) or agonist (YS-49) were screened. In experiment 2, the role of PI3K/AKT in Zn alleviation of HS-induced damage to JOs was evaluated with three JO types as control groups under baseline incubation temperature (40 °C) plus a 3 (JOs types) × 3 (Zn sources) factorial design under high temperature (44 °C). The results showed that the optimal concentrations of the PI3K-IN-1 and YS-49 for effectively inhibiting and promoting (p < 0.001) phosphorylation of PI3K and AKT were 16 μmol/L and 9 μmol/L, respectively. Adding Zn, especially Zn proteinate with moderate chelation strength (Zn-Prot M), alleviated (p < 0.001) the HS-induced increases in diamine oxidase content and lactate dehydrogenase activity in the media and the HS-induced decreases in JOs budding percentage, proportions of 5-ethynyl-2′-deoxyuridine and proliferating cell nuclear antigen positive cells, and the phosphorylation of PI3K and AKT. PI3K/AKT inhibition or activation reduced or enhanced (p < 0.05) the above alleviating effect of Zn, especially Zn-Prot M. These results indicate that the PI3K/AKT signaling pathway mediated the alleviation of HS-induced damage to integrity and barrier function of broiler JOs by supplemental Zn, particularly Zn-Prot M via promotion of cell proliferation. Full article

(This article belongs to the Special Issue Poultry Mineral and Vitamin Nutrition: Molecular Mechanisms and Nutritional Strategies)

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15 pages, 1219 KB

Open AccessArticle

Shell Metal Profiles of Caspian Bivalves Show Genus-Specific Patterns with Potential Relevance for Biomonitoring in the Southern Caspian Sea

by Shima Bakhshalizadeh, Rafael Mora-Medina and Nahúm Ayala-Soldado

Animals 2026, 16(10), 1491; https://doi.org/10.3390/ani16101491 (registering DOI) - 13 May 2026

Abstract

Bivalves are widely used in aquatic monitoring, but the potential of their shells to provide comparative metal signatures remains insufficiently explored in the Caspian Sea. This study quantified major and trace elements in empty shells of five bivalve genera (Cerastoderma, Didacna [...] Read more.

Bivalves are widely used in aquatic monitoring, but the potential of their shells to provide comparative metal signatures remains insufficiently explored in the Caspian Sea. This study quantified major and trace elements in empty shells of five bivalve genera (Cerastoderma, Didacna, Dreissena, Hypanis, and Mytilaster) collected from a single shell accumulation site on the southern Caspian coast. The aim was to assess intergeneric variability and provide a preliminary comparative framework for shell-based metal profiling. Element concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS), and median concentrations, internal residual enrichment factors, relative concentration factors, a relative multielement loading index, and centered log-ratio principal component analysis were applied as within-dataset comparative tools. Significant differences among genera were found for most elements. Dreissena and Cerastoderma showed the highest relative multielement loading, with comparatively elevated values of Cr, Fe, and Hg, whereas Hypanis showed marked element-specific deviations, particularly for Cu and Co. In contrast, Mytilaster and Didacna generally showed lower overall relative loading, although Mytilaster also displayed a strong Co-specific pattern. PCA-clr analysis showed structured genus-related separation based on multielement shell composition, with contrasting associations among Al, As, Cr, Fe, Co, Cu, Hg, and carbonate- or shell-associated elements such as Ba, Mg, Sr, Ti, and Zn. Overall, the results indicate that Caspian bivalve shells display distinct genus-related multielement profiles. Within the limitations of a single-site shell-accumulation dataset and the absence of paired environmental, tissue, mineralogical, and microstructural data, these findings should be interpreted as a preliminary comparative assessment rather than as evidence of environmental contamination or validated bioindicator performance. The results identify genera and elements that may deserve priority in future shell-based biomonitoring studies after validation with living populations, broader spatial replication, and paired sediment, water, particulate, and soft-tissue data. Full article

(This article belongs to the Topic Bridging Ecosystem Contamination and One Health: Integrating Environmental, Animal, and Human Risk Assessment)

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Graphical abstract

19 pages, 11981 KB

Open AccessArticle

Transcriptomic and Ultrastructural Analyses Reveal the Mechanisms of Accelerated Depuration Induced by Phyllodium pulchellum Extract in the Freshwater Snail Bellamya purificata

by Zhiqiang Wang, Enjie Chua, Fuguang Luo, Xiaoyun Zhou, Jie Huang, Jinxia Peng, Xianhui Pan and Yanhong Wen

Animals 2026, 16(10), 1490; https://doi.org/10.3390/ani16101490 (registering DOI) - 13 May 2026

Abstract

The commercial viability of B. purificata relies on efficient depuration. While P. pulchellum extract dramatically accelerates this process, its physiological and molecular mechanisms remain unknown. To address this, we integrated behavioural, histological, ultrastructural, and transcriptomic (RNA-seq) analyses to characterize the acute stress and [...] Read more.

The commercial viability of B. purificata relies on efficient depuration. While P. pulchellum extract dramatically accelerates this process, its physiological and molecular mechanisms remain unknown. To address this, we integrated behavioural, histological, ultrastructural, and transcriptomic (RNA-seq) analyses to characterize the acute stress and subsequent recovery phases of B. purificata exposed to the botanical extract. Extract exposure induced severe neuromuscular hyperextension response, with histological analysis revealing acute interstitial oedema and neuronal chromatolysis. This structural damage caused sustained cephalopodium extension and muscle fibre uncoupling. Transcriptomic profiling linked this neuromuscular dysfunction to conserved calcium-dependent adrenergic signalling modules and profound endogenous neuroendocrine disruption. The extract also induced cellular stress, downregulating the apoptosis inhibitor BIRC7 and eliciting transcriptomic signatures consistent with a DNA damage response. Crucially, during the short-term recovery phase, surviving tissues mounted a robust transcriptomic repair response. The snails systemically suppressed the cell cycle via MCM2-6 downregulation while upregulating GADD45 and RAD54B, suggesting a prioritization of genomic repair alongside partial morphological reorganization. Ultimately, P. pulchellum accelerates depuration via acute phytochemical stress and neuromuscular dysfunction. Importantly, this stress is accompanied by a highly coordinated transcriptomic repair response and partial short-term restoration, providing foundational molecular insights essential for evaluating and optimizing botanical depuration protocols. Full article

(This article belongs to the Section Aquatic Animals)

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17 pages, 1366 KB

Open AccessArticle

Identification and Spatial Differentiation of High-Risk Areas for Brown Bear Incidents in Yushu Prefecture, China, Using Machine Learning and Remote Sensing

by Xiaoli Guo, Jianyun Zhao, Yaxin Sun, Bo Zhai and Xinnan Ai

Animals 2026, 16(10), 1489; https://doi.org/10.3390/ani16101489 - 12 May 2026

Abstract

The Sanjiangyuan Region is among China’s most critical ecological function zones and serves as an important habitat for rare wildlife species such as brown bears and snow leopards. Driven by factors including climate change and intensified human activities, human–wildlife conflicts have become increasingly [...] Read more.

The Sanjiangyuan Region is among China’s most critical ecological function zones and serves as an important habitat for rare wildlife species such as brown bears and snow leopards. Driven by factors including climate change and intensified human activities, human–wildlife conflicts have become increasingly frequent on the Qinghai–Tibet Plateau, threatening the living space of both herders and wildlife. This study centers on the Yushu Tibetan Autonomous Prefecture in Qinghai Province, integrating multi-source remote sensing data with field survey data, and employs the Maximum Entropy Model (MaxEnt) MaxEnt model and the BIOMOD2 framework to simulate high-risk areas for brown bear incidents. Results indicate that the BIOMOD2 ensemble model (EMca) achieved the highest predictive accuracy, with the Random Forest (RF) model demonstrating strong robustness among individual models. Digital Elevation Model (DEM), Soil Surface Moisture (SSM), Fractional Vegetation Cover (FVC), and Human Footprint (HFP) were identified as the primary factors influencing the spatial distribution of brown bear incidents. High-risk areas exhibited significant clustering, mainly concentrated in the southern and southeastern regions of Qumalai, Nangchen, and Chindu; the eastern part of Zadoi County; and the central and southern parts of Yushu City, particularly within the elevation range of 4304–4544 m, where human activity intensity is relatively low. The core high-risk zone is located along the Tongtian River in southern Qumalai County, demonstrating strong spatial connectivity. By investigating the spatial distribution patterns and driving mechanisms of brown bear incidents in Yushu Prefecture, this study offers some references for government agencies to formulate strategies that promote harmonious coexistence between humans and nature. Full article

(This article belongs to the Topic Wildlife Intelligent Monitoring: Advancing Conservation Through Visual and Acoustic Monitoring Technologies)

18 pages, 427 KB

Open AccessArticle

Trapping Callinectes sapidus (Atlantic Blue Crab) in the Mediterranean: What Can Be Learned from Carcinus maenas (European Green Crab) Pest Management

by Jonathan W. Burnett, Hannah Ohnstad, Jorg D. Hardege and Helga D. Bartels-Hardege

Animals 2026, 16(10), 1488; https://doi.org/10.3390/ani16101488 - 12 May 2026

Abstract

Invasive marine crustaceans present ecological and socio-economic challenges, particularly where high fecundity, behavioural plasticity, and environmental tolerance limit the effectiveness of conventional control measures. The Atlantic blue crab, Callinectes sapidus, has expanded across the Mediterranean, where it exerts strong predatory pressure on [...] Read more.

Invasive marine crustaceans present ecological and socio-economic challenges, particularly where high fecundity, behavioural plasticity, and environmental tolerance limit the effectiveness of conventional control measures. The Atlantic blue crab, Callinectes sapidus, has expanded across the Mediterranean, where it exerts strong predatory pressure on native species and aquaculture resources, yet management efforts rely largely on traditional baited trapping. Drawing on extensive evidence from the global management of the European green crab, Carcinus maenas, we evaluate why conventional trapping has failed to achieve sustained population suppression in invasive brachyuran crabs. We synthesise lessons from green crab control to identify common biological and operational constraints, including rapid compensatory population responses, bycatch, and limited behavioural selectivity. We then examine the potential of semiochemical-based strategies—incorporating olfactory cues—within an integrated pest management (IPM) framework. Semiochemical-enhanced approaches offer the capacity to directly exploit species-specific sensory ecology, improve trap selectivity, and reduce non-target impacts, addressing fundamental limitations of existing methods. We argue that prioritising such IPM, rather than further optimisation of traditional trapping alone, represents the most realistic pathway for long-term mitigation of C. sapidus in the Mediterranean. While eradication remains improbable, strategically deployed semiochemical-based control could substantially enhance suppression efficiency and inform broader invasive species management. Full article

(This article belongs to the Special Issue The Invasive Blue Crab: Implications for Fisheries, Aquaculture and One Health Perspective)

15 pages, 1485 KB

Open AccessArticle

Muscle Metabolomic Responses of Dumont and Mongolian Sheep to Alfalfa Hay- and Corn Straw-Based Diets: An Untargeted Metabolomics Study

by Ran Zhang, Meila Na, Wenliang Guo, Jing Zhang and Renhua Na

Animals 2026, 16(10), 1487; https://doi.org/10.3390/ani16101487 - 12 May 2026

Abstract

This study evaluated the effects of forage source on the longissimus dorsi muscle metabolomic profiles of Dumont and Mongolian sheep. A total of 24 male sheep, including Dumont sheep (DS) and Mongolian sheep (MS), were assigned to a 2 × 2 factorial design [...] Read more.

This study evaluated the effects of forage source on the longissimus dorsi muscle metabolomic profiles of Dumont and Mongolian sheep. A total of 24 male sheep, including Dumont sheep (DS) and Mongolian sheep (MS), were assigned to a 2 × 2 factorial design with two breeds and two forage sources: alfalfa hay (AH) and corn straw (CS). The four groups were DSAH, DSCS, MSAH, and MSCS, with six lambs per group. Untargeted metabolomics was used to characterize muscle metabolic profiles after a 90-day feeding period. Stable metabolomic separations were mainly observed between forage treatments within each breed, namely DSAH vs. DSCS and MSAH vs. MSCS, whereas breed comparisons under the same forage condition showed limited separation and weaker model stability. OPLS-DA combined with univariate analysis identified 101 and 100 differential metabolites in the DSAH vs. DSCS and MSAH vs. MSCS comparisons, respectively. Pathway enrichment analysis indicated that forage-associated metabolic differences were mainly related to amino acid metabolism, lipid metabolism, and energy metabolism. AH feeding was associated with broader changes in muscle metabolic pathways than CS feeding, particularly in pathways related to nutrient utilization and lipid-related metabolism. These findings suggest that the forage source is closely associated with muscle metabolic variation in fattening lambs, while possible breed-related differences in metabolic responsiveness require further validation. Full article

(This article belongs to the Section Animal Nutrition)

20 pages, 1671 KB

Open AccessSystematic Review

Effects of Dietary Crude Glycerol Supplementation on Performance, Egg Quality, and Yolk Fatty Acids in Laying Hens: A Systematic Review and Meta-Analysis

by Panneepa Sivapirunthep, Rasheed Olayiwola Sulaimon, Katatikarn Sahatsanon, Anuraga Jayanegara, Pattraphorn Patthararangsarith and Chanporn Chaosap

Animals 2026, 16(10), 1486; https://doi.org/10.3390/ani16101486 - 12 May 2026

Abstract

This study evaluated the effects of dietary crude glycerol supplementation on laying performance, egg quality traits, and egg yolk fatty acid composition in laying hens. A systematic search of peer-reviewed literature from major scientific databases identified thirteen eligible studies. Effect sizes were calculated [...] Read more.

This study evaluated the effects of dietary crude glycerol supplementation on laying performance, egg quality traits, and egg yolk fatty acid composition in laying hens. A systematic search of peer-reviewed literature from major scientific databases identified thirteen eligible studies. Effect sizes were calculated as mean differences using random-effects models, and subgroup and meta-regression analyses were conducted to assess the influence of inclusion level, hen age, strain, and dose–response relationships. Moderate inclusion of crude glycerol (≤4%) significantly increased egg production (MD = +0.71 percentage points; p = 0.019) and egg mass (MD = +1.08 g; p = 0.007). External egg quality traits, including shell thickness, shell breaking strength, and shell percentage, were not significantly affected, while albumen height decreased slightly (MD = −0.14 mm; p = 0.004) and Haugh unit remained unchanged. Crude glycerol supplementation also increased linoleic acid, total unsaturated fatty acids, and total polyunsaturated fatty acids (p < 0.001). Responses varied with inclusion level, hen age, and strain, and a positive dose–response relationship between crude glycerol level and yolk linoleic acid was observed in white-egg strains. Overall, moderate crude glycerol inclusion can partially replace conventional dietary energy sources with minimal adverse effects on egg quality. Full article

(This article belongs to the Section Animal Nutrition)

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10 pages, 531 KB

Open AccessCommunication

Effect of Racking Systems Versus Enriched Terraria on Fecal Glucocorticoid Metabolites in Four Species of Captive Snakes: A Pilot Study

by Sergi Olvera-Maneu, Marçal Regidor, Paula Serres-Corral, Albert Martínez-Silvestre and Manel López-Béjar

Animals 2026, 16(10), 1485; https://doi.org/10.3390/ani16101485 - 12 May 2026

Abstract

Fecal glucocorticoid metabolites (FGM) are widely used to assess hypothalamic–pituitary–adrenal (HPA) activity in vertebrates, but their applicability to reptiles, and more specifically to snakes, remains poorly explored. The objective of the present study was to determine how changes in housing conditions, from a [...] Read more.

Fecal glucocorticoid metabolites (FGM) are widely used to assess hypothalamic–pituitary–adrenal (HPA) activity in vertebrates, but their applicability to reptiles, and more specifically to snakes, remains poorly explored. The objective of the present study was to determine how changes in housing conditions, from a standard racking system to enriched terraria, affect fecal glucocorticoid metabolite concentrations as a proxy potentially related to endocrine activity and stress response. A total of 58 fecal samples were collected across three different phases from 12 snakes representing four species: Boa constrictor (BC), Lampropeltis polyzona (LP), Pantherophis guttatus (PG), and Python regius (PR). FGM concentrations ranged from 54.9 to 832.2 ng/g, with a mean value of 298.4 ± 171.6 ng/g (mean ± SD). Data showed marked inter-individual variability, while within-individual concentrations remained relatively stable across experimental phases. PG exhibited the highest FGM concentrations during the study, with LP showing intermediate levels and PR and BC the lowest. The results showed that housing conditions did not have a significant effect on FGM concentrations in the studied population. In conclusion, the present study showed that fecal hormone analysis provides an integrated measure of glucocorticoid metabolites concentrations over time, potentially reflecting physiological differences among snake species. Full article

(This article belongs to the Section Animal Physiology)

28 pages, 13202 KB

Open AccessArticle

RCAF-Net: Wildlife Target Detection in Complex Forest Scenarios

by Xiuling Yu, Chenxiao Qu, Yifu Xu, Senyue Guo, Lili Fu and Yang Zhou

Animals 2026, 16(10), 1484; https://doi.org/10.3390/ani16101484 - 12 May 2026

Abstract

This study focuses on wildlife target detection in complex forest environments in Northeast China, where monitoring images are often affected by background interference, frequent occlusion, and large target scale variation. In addition, distant animals usually appear as small targets with limited local detail [...] Read more.

This study focuses on wildlife target detection in complex forest environments in Northeast China, where monitoring images are often affected by background interference, frequent occlusion, and large target scale variation. In addition, distant animals usually appear as small targets with limited local detail information, increasing the difficulty of reliable detection. To address these challenges while maintaining deployment efficiency, an improved wildlife target detection model, RCAF-Net, is proposed based on YOLO11n. The proposed method enhances shallow feature representation, strengthens multi-scale contextual modeling, improves cross-layer feature fusion consistency, and introduces a lightweight detection head to balance detection accuracy and computational cost. Experimental results on a self-built dataset of eight typical wildlife species show that RCAF-Net achieves Precision, Recall, mAP@0.5, and mAP@0.5:0.95 values of 89.3%, 78.4%, 87.3%, and 67.3%, respectively, improving upon YOLO11n by 4.1%, 2.6%, 3.9%, and 3.4%. On the Wildlife Computer Vision Model dataset, the proposed model also achieved improved generalization performance in cross-dataset testing. In addition, the model operated at approximately 27 FPS on the Jetson TX2 NX platform. These results suggest that RCAF-Net has potential applicability for automated wildlife monitoring in complex forest environments. Full article

(This article belongs to the Section Wildlife)

23 pages, 847 KB

Open AccessArticle

From Concept to Perception: Equestrian Definitions of Harmony and Visual Attention in Horse–Rider Evaluation

by Inga A. Wolframm, Madita Everding, Varvara Savulchyk, Jorinde Borssen and Debby D. M. Gudden

Animals 2026, 16(10), 1483; https://doi.org/10.3390/ani16101483 - 12 May 2026

Abstract

In equestrian circles, horse–rider harmony is understood intuitively, yet clear criteria are lacking. This study examined how different equestrians conceptualized and visually assessed harmony and how this influenced scoring. Qualitative interviews were combined with eye tracking technology. Thirty equestrians assessed five videos of [...] Read more.

In equestrian circles, horse–rider harmony is understood intuitively, yet clear criteria are lacking. This study examined how different equestrians conceptualized and visually assessed harmony and how this influenced scoring. Qualitative interviews were combined with eye tracking technology. Thirty equestrians assessed five videos of horse–rider combinations performing in dressage, showjumping, eventing, working equitation and Icelandic riding, with eye movements being recorded using a mounted eye tracker. Verbal definitions were analyzed using thematic analysis, revealing three overarching themes: Horse Behavior, Horse–Rider Connection, and Rider Influence. Number of fixations and duration of fixation were reduced using principal component analysis (PCA), yielding five components each. These explained 70.9% and 64.5% of variance, respectively. Linear mixed-effects models showed significant effects for two PCA components: frequent fixation on the horse’s ears and eyes relative to the horse’s shoulder and rider leg predicted lower harmony scores (B = −0.34, SE = 0.13, z = −2.53, p < 0.05), whereas longer dwell time on the rider’s shoulder relative to the rider’s leg predicted higher scores (B = 0.25, SE = 0.12, z = 2.12, p < 0.05). Ears and eyes were also the most frequent first fixation. Harmony appears to be a shared construct at the conceptual level, but is personally enacted at the practical level. Equine facial expressions and rider posture serve as important perceptual indicators. Full article

(This article belongs to the Special Issue Equine Cognition and Behavior in Human–Horse Interactions)

13 pages, 537 KB

Open AccessArticle

Improving Rainbow Trout (Oncorhynchus mykiss) Juvenile Performance and Intestinal Condition Through Lactic Acid Bacteria Feed Fermentation

by Gustavo Alberto Arbelaez Rojas, Nataly Neves Oliveira dos Santos, Larissa Stockhausen, Bia Pacheco Kozikowski, Mariana Bender, Fernanda Regina Delzivo, Luiz Augusto Cipriani, Everton Skoronski, Pedro Toledo, German Merino Araneda and Thiago El Hadi Perez Fabregat

Animals 2026, 16(10), 1482; https://doi.org/10.3390/ani16101482 - 12 May 2026

Abstract

This study evaluated the effects of feed fermented with Lactobacillus acidophilus and Lacticaseibacillus rhamnosus on the growth performance and intestinal condition of the juvenile rainbow trout Oncorhynchus mykiss. Three fermentation times (3, 6, and 9 h) were compared against a non-fermented control [...] Read more.

This study evaluated the effects of feed fermented with Lactobacillus acidophilus and Lacticaseibacillus rhamnosus on the growth performance and intestinal condition of the juvenile rainbow trout Oncorhynchus mykiss. Three fermentation times (3, 6, and 9 h) were compared against a non-fermented control diet. The experimental design followed a randomized block scheme, with four treatments and four replicates. Juvenile rainbow trout (22.2 ± 0.9 g) were distributed among 16 tanks (500 L) connected to a recirculation system at a density of 15 fish per tank. A commercial diet (45% crude protein) was fermented through solid-state fermentation. After 60 days, growth performance and intestinal condition were assessed. The microbial fermentation of extruded commercial feeds was efficient, increasing the lactic acid bacteria count and reducing pH within 6 h. Feeding fermented feeds reduced feed intake without affecting fish growth performance. Feed fermented for 3 and 6 h improved feed efficiency, and evidence of enhanced nitrogen utilization was observed. In addition, feed fermented for 6 h increased intestinal colonization by lactic acid bacteria and enhanced intestinal lipase activity. Feed fermented for 9 h showed evidence of improved intestinal condition. Overall, this study indicates that feed fermentation improves feed efficiency and intestinal condition in rainbow trout. Full article

(This article belongs to the Special Issue Redefining Aquaculture Nutrition: Innovations in Novel Ingredients, Functional Feeds, and Precision Feeding)

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21 pages, 1865 KB

Open AccessFeature PaperArticle

Comparing Spider Sampling Methods in a Eucalypt Forest in Wet and Dry Conditions

by Rachael Harris, Robert Raven, Andrew Maxwell and Peter J. Murray

Animals 2026, 16(10), 1481; https://doi.org/10.3390/ani16101481 - 12 May 2026

Abstract

Environmental variability, such as fluctuations in rainfall, can strongly influence spider population dynamics and assemblage composition. The study examined whether rainfall in the preceding three months, i.e., wet or dry conditions, using three different methods in the same sites within a eucalyptus forest, [...] Read more.

Environmental variability, such as fluctuations in rainfall, can strongly influence spider population dynamics and assemblage composition. The study examined whether rainfall in the preceding three months, i.e., wet or dry conditions, using three different methods in the same sites within a eucalyptus forest, influenced the overall species and abundance of spiders captured and thus how wet or dry conditions influenced the overall spider assemblage and community structure. In south-east Queensland, Australia, rainfall is highly variable throughout the year and does not conform to distinct wet or dry seasons; therefore, “wet” and “dry” classifications in this study refer specifically to preceding rainfall conditions rather than seasonal categories. Sampling was conducted during dry conditions (75 mL of rain in the three months preceding collection) and during wet conditions (300 mL of rain in the three months preceding collection) to assess overall differences in spider richness, diversity and assemblage composition between wet and dry conditions by combining data from the three sampling methods. Species richness was significantly higher in dry conditions compared to the wet conditions. Diversity indices indicated that the more common spider species remained consistent between wet and dry conditions. Ordination analyses revealed changes between wet and dry conditions, primarily driven by fluctuations with less common spider species, rather than community changes at the family level. For vibration-based collections of spiders, only 30.5% of species overlapped between wet and dry conditions, whereas family-level overlap was 75%, indicating rainfall-driven changes occurred primarily at the species level rather than at the family level. Spider abundance was consistently higher under dry conditions across all methods. In vibration-based collections, 90% of species was collected within 60 min. However, using this method, species appeared more slowly under wet conditions, suggesting that rainfall may influence spider responses to vibrational stimuli. Survey method strongly influenced species richness with night hand collection of spiders resulting in the greatest number of species observed. Spider species richness and diversity collected using the vibration-based method were similar in wet and dry conditions and between sites. This supports the reliability of this method for sampling spiders that respond to vibrations and should be used complementarily with other survey methods. Full article

(This article belongs to the Section Wildlife)

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18 pages, 3481 KB

Open AccessArticle

Identification of Key Genes Associated with Feed Utilization Efficiency in Penaeus vannamei Fed a Plant-Based Diet Using WGCNA

by Hao Zhang, Yuhao Xu, Juan Sui, Qiang Fu, Mianyu Liu, Jian Tan, Jie Kong, Kun Luo, Xianhong Meng, Sheng Luan and Ping Dai

Animals 2026, 16(10), 1480; https://doi.org/10.3390/ani16101480 - 12 May 2026

Abstract

Overcoming fishmeal dependence is crucial for the sustainable development of Penaeus vannamei aquaculture, yet the molecular mechanisms underlying the efficient utilization of plant-based diets remain poorly understood. In this study, residual feed intake (RFI) was used as an indicator to investigate these mechanisms. [...] Read more.

Overcoming fishmeal dependence is crucial for the sustainable development of Penaeus vannamei aquaculture, yet the molecular mechanisms underlying the efficient utilization of plant-based diets remain poorly understood. In this study, residual feed intake (RFI) was used as an indicator to investigate these mechanisms. Transcriptome sequencing of the intestine, hepatopancreas, and muscle was performed on shrimp fed a plant-based diet, followed by weighted gene co-expression network analysis (WGCNA) and validation in an independent population. Phenotypic analysis revealed extensive variation in growth performance and RFI among individuals fed the plant-based diet. WGCNA identified four tissue-specific modules significantly associated with RFI, from which 20 hub genes were screened. Independent validation confirmed that seven genes were significantly differentially expressed between high- and low-feed-efficiency groups (q < 0.1): five in the intestine (LOC113811628, LOC113811631, LOC113824170, LOC113817752, LOC113811632) and two in the hepatopancreas (LOC113809216, LOC113820990). These genes are involved in mitochondrial function, energy metabolism, intracellular pH homeostasis, and nucleic acid metabolism, suggesting potential coordination between the intestine and hepatopancreas in response to plant-based diets. Collectively, these findings provide insights into the genetic basis of shrimp adaptation to plant-based diets and offer candidate molecular targets that may inform selective breeding efforts aimed at improving feed efficiency in P. vannamei. Full article

(This article belongs to the Special Issue Genetic and Genomic Mechanisms Underlying Economically Important Traits in Aquatic Animals)

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24 pages, 16709 KB

Open AccessArticle

Underwater Multi-Target Tracking and Behavioral Rhythm Analysis of Chinese Giant Salamander Based on TransTrack-OC-SORT

by Nanqing Sun, Xinyao Yang, Mokai Xie, Haotian Qian and Junyi Chen

Animals 2026, 16(10), 1479; https://doi.org/10.3390/ani16101479 - 12 May 2026

Abstract

To address the challenges posed by traditional tracking algorithms in adapting to complex underwater environments characterized by nonlinear motion, drastic morphological changes, mimicry camouflage, and frequent occlusions in wild Chinese giant salamanders, this study proposes a multi-object tracking and behavior analysis method based [...] Read more.

To address the challenges posed by traditional tracking algorithms in adapting to complex underwater environments characterized by nonlinear motion, drastic morphological changes, mimicry camouflage, and frequent occlusions in wild Chinese giant salamanders, this study proposes a multi-object tracking and behavior analysis method based on the TransTrack-OC-SORT algorithm. The algorithm employs a dual-branch Transformer motion predictor to replace linear Kalman filtering, effectively capturing nonlinear motion patterns such as velocity changes and directional turns exhibited by salamanders. Simultaneously, it introduces the BIOU matching metric, which integrates center distance and aspect ratio penalties with overlap degree, thereby enhancing the robustness of associations in scenarios involving occlusion and mimicry camouflage. The results indicate that the multi-object tracking accuracy (MOTA) based on the TransTrack-OC-SORT algorithm reaches 80.9%, while the identity preservation metric (IDF1) achieves 83.7%. Quantitative behavioral analysis based on continuous trajectory data obtained from this algorithm revealed significant diurnal behavioral rhythms in the Chinese giant salamander. During the daytime, stationary behavior accounted for 95.5% of the total behavioral duration, while swimming for ventilation and foraging behaviors constituted only 4.1% and 0.4%, respectively. At night, the salamander’s behavioral patterns underwent fundamental changes; although stationary behavior remained dominant (approximately 72.6%), the proportions of swimming for ventilation and foraging behaviors significantly increased to 15.1% and 12.3% of the nocturnal period, respectively. These findings enhance our understanding of the salamander’s ecological habits from the perspectives of visual adaptation, energy allocation, and predation strategies. This study provides a reliable technical tool for non-invasive behavioral monitoring and rhythm research in endangered amphibians. Full article

(This article belongs to the Special Issue Artificial Intelligence as a Useful Tool in Behavioural Studies)

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12 pages, 613 KB

Open AccessArticle

Reducing Companion Animal Abandonment During Disaster-Driven Relocation: A Four-Year Study in Maceió, Brazil

by Keityane de Oliveira e Silva, Helena Emília Oliveira Teodosio, Juliana de Oliveira Bernardo, Sharacely de Souza Farias and Pierre Barnabé Escodro

Animals 2026, 16(10), 1478; https://doi.org/10.3390/ani16101478 - 12 May 2026

Abstract

In March 2018, seismic events associated with rock salt mining in Maceió, northeastern Brazil, led to the emergency relocation of families from risk areas, resulting in increased companion animal abandonment. This study assessed the association between systematic monitoring and environmental education and the [...] Read more.

In March 2018, seismic events associated with rock salt mining in Maceió, northeastern Brazil, led to the emergency relocation of families from risk areas, resulting in increased companion animal abandonment. This study assessed the association between systematic monitoring and environmental education and the reduction in abandonment during these relocation processes. Between March 2018 and September 2020, 567 animals were recorded in affected households, of which only 245 (43.2%) were relocated with their guardians. In response, the Integra Animal Project was implemented, integrating environmental education, continuous monitoring, sanitary management, and population control. By December 2024, 2559 households and 6673 animals had been monitored. A substantial reduction in abandonment and escape rates was observed over time, with abandonment decreasing from 56.8% to 5.45%. Cats showed significantly higher escape rates than dogs (chi-square test). These findings suggest that integrated strategies combining monitoring and environmental education are associated with improved animal retention during disaster-driven relocation, supporting their relevance for animal welfare, public health, and One Health approaches. Full article

(This article belongs to the Section Companion Animals)

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22 pages, 3157 KB

Open AccessArticle

Harnessing Machine Learning and Molecular Docking to Decode the Fatty Acid Dynamics in High-Altitude Yak Milk

by Chaoyun Yang, Yao Pan, Yi He and Ran Guan

Animals 2026, 16(10), 1477; https://doi.org/10.3390/ani16101477 - 12 May 2026

Abstract

This study investigated the fatty acid profile of Muli yak (Bos grunniens) milk and its relationship with compositional parameters across different parities. Milk samples from second-, third-, and fourth-parity yaks were analysed for protein, fat, vitamins, minerals, and 37 fatty acids [...] Read more.

This study investigated the fatty acid profile of Muli yak (Bos grunniens) milk and its relationship with compositional parameters across different parities. Milk samples from second-, third-, and fourth-parity yaks were analysed for protein, fat, vitamins, minerals, and 37 fatty acids using gas chromatography. Statistical analyses included ANOVA, correlation analysis, principal component analysis (PCA), machine learning algorithms, and molecular docking. Parity significantly affected 15 components (p < 0.05), with third-parity milk showing the highest eicosapentaenoic acid (EPA, C20:5n3) and arachidonic acid (ARA, C20:4n6) concentrations. Among 134 significant correlations, calcium-ARA and ARA-EPA exhibited strong positive associations (|r| > 0.67). PCA explained 54.2% of the variance through three principal components, differentiating samples by parity. The optimal prediction models were ARA-XGBoost, EPA-Random Forest, ALA-GAM, and LA-SVM, with calcium and protein serving as key predictors. Molecular docking revealed that EPA-FABP2 had the lowest binding energy. These parity-related shifts in functional long-chain polyunsaturated fatty acids are meaningful for the nutritional value of yak milk (e.g., omega-3/omega-6 profile) and may also influence technological properties associated with milk fat composition (e.g., oxidative stability and processing behaviour), supporting parity-oriented quality evaluation and targeted utilisation of yak milk. Full article

(This article belongs to the Section Animal System and Management)

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21 pages, 4469 KB

Open AccessArticle

Comparative Analysis of Gastrointestinal Microbiota Along the Digestive Tract in Sika Deer and Reindeer and Prediction of Their Potential Function

by Xinyu Peng, Huansheng Han, Ruihong Hu, Fanzhi Kong and Yuhan Lu

Animals 2026, 16(10), 1476; https://doi.org/10.3390/ani16101476 - 11 May 2026

Abstract

Gastrointestinal microbiota are essential for fiber degradation, energy metabolism, nutrient utilization, and environmental adaptation in ruminants. Although sika deer and reindeer both belong to the family Cervidae, they differ in ecology, feeding habits, and digestive physiology, which may be reflected in their gastrointestinal [...] Read more.

Gastrointestinal microbiota are essential for fiber degradation, energy metabolism, nutrient utilization, and environmental adaptation in ruminants. Although sika deer and reindeer both belong to the family Cervidae, they differ in ecology, feeding habits, and digestive physiology, which may be reflected in their gastrointestinal microbiota. Here, we used 16S rRNA amplicon sequencing to characterize the gastrointestinal microbial communities of healthy 5-year-old male sika deer and reindeer, with particular attention to taxonomic composition, diversity patterns, and predicted functional profiles across anatomical segments. Both species were dominated by a limited number of highly abundant taxa, but clear interspecific differences were observed. At the phylum level, Bacillota and Bacteroidota predominated in both species, whereas Methanobacteriota was more abundant in reindeer and Bacillota was relatively more abundant in sika deer. At the genus level, methanogen-associated taxa were more prominent in reindeer, whereas Bacteroides, Prevotellaceae, and fiber-degradation-related taxa were more abundant in sika deer. Distinct segment-specific microbial patterns were observed along the gastrointestinal tract, especially among the foregut, small intestine, and hindgut. Alpha diversity varied across segments, whereas beta diversity showed clear separation among segments. Functional prediction indicated differences mainly in the overall structure of predicted functional profiles rather than in individual pathways. These findings provide baseline information for understanding gastrointestinal microecology and adaptive mechanisms in cervids. Full article

(This article belongs to the Section Animal Nutrition)

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