Autonomous University of Baja California Sur

The assessment of individual specialization in marine top predators provides insight into their role in marine ecosystems. The northern elephant seal (Mirounga angustirostris) is considered a generalist consumer; however, adult females could exhibit individual specialization to meet the energetic demands of reproduction. We evaluated foraging variability and individual specialization in adult females from the San Benito Archipelago (Mexican Pacific), using vibrissae from recently weaned pups as maternal proxies. Stable isotopes analyses (δ13C and δ15N) were conducted on vibrissae segments collected in two breeding seasons (2016–17 and 2022–23). Isotopic profiles showed consistent temporal patterns across years, with ¹³C and ¹⁵N-enriched values during the post-molting migration, and ¹³C-depleted values during lactation, reflecting maternal energy transfer. At colony level, isotopic niche widths (4.5–7.3‰2) indicate a generalist strategy. However, individual niches were considerably smaller (< 1‰2), revealing within colony partitioning. The individual specialization index (SI) revealed that 65

The present study aimed to assess the effects of chitosan nanocapsules loaded with synthetic carvacrol and thymol (structurally analogous to those in oregano oil) on the antioxidant and molecular response of Litopenaeus vannamei subjected to acute thermal stress. Chitosan nanocapsules (of 246 nm) were prepared and incorporated into shrimp feed at eight concentrations in triplicate: 0.0 (0ChNP), 0.033mg g− 1 (0.03ChNP), 0.1mg g− 1 (0.1ChNP), 0.2mg g− 1 (0.2ChNP), 0.3mg g− 1 (0.3ChNP), 0.467mg g− 1 (0.5ChNP), 0.633mg g− 1 (0.6ChNP), and 0.8mg g− 1 (0.8ChNP). Twenty-four aquariums, each containing three shrimp (10.25 ± 1.14 g), were fed for two weeks. The first 8 days at 27 ± 0.5 °C, followed by a gradual temperature increase to 39 °C. Thereafter, shrimps were sampled, and the hepatopancreas dissected and divided into two, and individually stored in RNAlater for transcriptomic and qPCR analysis. The groups 0ChNP, 0.03ChNP, and 0.3ChNP were selected for transcriptomic analysis based on their physical appearance, and mortality rate. At 0.03ChNP, significant upregulation of genes associated with innate immunity, vesicular trafficking, and autophagy was detected, suggesting an activated protective response. On the other hand, the qPCR on anti-oxidative enzymes, catalase and glutathione peroxidase, showed lower levels than in the control experiments suggesting reduced oxidative stress when chitosan nanocapsules were supplied, especially with 0.3ChNP. In conclusion, chitosan nanocapsules delivering carvacrol and thymol at 0.3 mg g− 1 of feed modulate distinct molecular pathways that contribute to thermal stress resilience in shrimp. Doses below or above this threshold were ineffective or detrimental under the conditions tested.

Mast cells (MCs) are myeloid-derived immune cells that differentiate in peripheral tissues, where they are strategically located near epithelial surfaces. In the gastrointestinal tract, MCs regulate immune response through the release of mediators such as histamine, cytokines, and proteases; however, their excessive activation promotes inflammation, increases intestinal permeability, and contributes to disorders such as food allergies, inflammatory bowel disease, and chronic intestinal inflammation. Probiotics are live microorganisms that confer health benefits to the host when administered in adequate amounts and play a key role in gut immune regulation by modulating the microbiota, reinforcing epithelial barrier integrity, and promoting anti-inflammatory responses. Although MCs and probiotics have been extensively studied independently, their functional interplay in gut health and disease remains poorly defined. Here, we propose that probiotic-mast cell interactions represent an underexplored immunoregulatory axis in intestinal homeostasis. This mini-review synthesizes current evidence on the crosstalk between probiotics and MCs, highlighting the limited mechanistic understanding of these interactions and its potential therapeutic implications.