Research Article
Mortality, Cortisol, Glucose and Plasma Ion Responses of Oreochromis variabilis to Transport Stress Under Low Oxygen and High Loading Density
Anne Mokoro*
Issue:
Volume 14, Issue 1, February 2026
Pages:
1-11
Received:
19 January 2026
Accepted:
30 January 2026
Published:
19 March 2026
DOI:
10.11648/j.ajls.20261401.11
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Abstract: Live fish transportation is an essential component of aquaculture supply chains, yet it exposes fish to acute stressors including confinement, crowding, mechanical disturbance, and progressive deterioration of water quality typically associated with sealed transport systems. These stressors can impair welfare, disrupt physiological homeostasis, and increase mortality. This study quantified transport stress responses in Oreochromis variabilis by evaluating mortality and changes in endocrine, metabolic, and osmoregulatory indicators under low oxygen and high loading density conditions during road transport in sealed polythene bags. Fish were packaged at five loading weights (1, 3, 5, 7, and 9 kg) under varying oxygen supply levels. Blood sampling was conducted at the start and end of transportation to determine serum cortisol and glucose concentrations and plasma sodium (Na⁺) and chloride (Cl⁻) ions. Mortalities remained low and did not differ significantly among treatments at 1–5 kg loading weights (p > 0.05). However, mortality increased significantly at 7 and 9 kg loading weights (p < 0.05), indicating that excessive loading density was the dominant risk factor for survival regardless of oxygen level. Cortisol and glucose concentrations increased markedly after transport across all treatments compared with baseline (p < 0.01), confirming activation of the hypothalamic–pituitary–inter-renal axis and stress-related metabolic mobilisation. Plasma Na⁺ significantly declined post-transport (p < 0.05), while Cl⁻ concentrations differed significantly between baseline and post-transport and varied with oxygen supply (p < 0.05), suggesting impaired ion regulation in response to transport-induced hypoxia and crowding. Overall, the findings demonstrate that high loading density intensifies transport stress in O. variabilis and compromises survival and physiological stability. Optimisation of loading density and oxygen management is therefore recommended to improve welfare and reduce transport losses in culture systems.
Abstract: Live fish transportation is an essential component of aquaculture supply chains, yet it exposes fish to acute stressors including confinement, crowding, mechanical disturbance, and progressive deterioration of water quality typically associated with sealed transport systems. These stressors can impair welfare, disrupt physiological homeostasis, and...
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Research Article
Human Milk Oligosaccharides (HMOs) in Infant Neurodevelopment: Evidence Linking Gut–brain Signaling to Cognitive Outcomes
Issue:
Volume 14, Issue 1, February 2026
Pages:
12-18
Received:
11 February 2026
Accepted:
27 February 2026
Published:
19 March 2026
DOI:
10.11648/j.ajls.20261401.12
Downloads:
Views:
Abstract: This narrative review summarizes current evidence on the association between human milk oligosaccharides (HMOs) and infant neurodevelopment. HMOs are complex bioactive carbohydrates naturally present in human breast milk and are increasingly recognized for their potential role in supporting early brain development through interactions with the gut microbiome, immune system, and metabolic pathways. Relevant literature was identified through structured searches of PubMed, Scopus, and Web of Science covering studies published between 2000 and 2025. The review included human observational cohort studies, mechanistic research, and preclinical models that examined neurodevelopmental outcomes such as cognitive function, language acquisition, motor skills, and socio-emotional development in infants and young children. Current human evidence, although largely observational, suggests that exposure to certain HMOs—particularly fucosylated and sialylated structures such as 2′-fucosyllactose (2′-FL), 3′-sialyllactose (3′-SL), and 6′-sialyllactose (6′-SL)—may be associated with improved neurodevelopmental outcomes. Infants exposed to higher levels of these HMOs during early life have been reported to show better cognitive performance, language development, and behavioral regulation. Early-life exposure appears especially important, as this period coincides with rapid brain growth and neural network formation. Several biological mechanisms may explain these associations. HMOs influence the gut–brain axis by promoting beneficial microbiota, particularly Bifidobacterium, which produce metabolites that can affect neural signaling and brain development. Additionally, sialylated HMOs provide sialic acid, a key component required for the synthesis of gangliosides and myelin that support neuronal connectivity and signal transmission. HMOs may also contribute to immune regulation and anti-inflammatory processes, helping to protect the developing brain from inflammatory stress. Despite promising findings, causal evidence remains limited. Most studies are observational and vary in design, HMO measurement methods, and participant characteristics. Important confounding factors, including maternal secretor status, breastfeeding duration, maternal nutrition, and socioeconomic influences, may affect observed associations. Furthermore, randomized controlled trials investigating direct neurodevelopmental effects of specific HMOs are still scarce. Future research should prioritize standardized HMO quantification, larger longitudinal cohorts, integration of neuroimaging techniques, and well-designed interventional trials to better clarify the role of HMOs in early brain development and long-term cognitive outcomes.
Abstract: This narrative review summarizes current evidence on the association between human milk oligosaccharides (HMOs) and infant neurodevelopment. HMOs are complex bioactive carbohydrates naturally present in human breast milk and are increasingly recognized for their potential role in supporting early brain development through interactions with the gut ...
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