Dietary Sodium Lactate Alleviates Ammonia Stress‐Induced Growth Impairment, Oxidative Damage and Metabolic Disorder in Juvenile Yellow Catfish

Dietary vitamin E alleviates ammonia-induced effects on survival, anti-oxidant and immune response of post-larval Pacific white shrimp.

It remains unknown whether vitamin E (VE), a fat-soluble vitamin known for its potent antioxidant effects, alleviates the stress caused by ammonia-N exposure in post-larval Pacific white shrimp (Penaeus vannamei). Five isonitrogenous (crude protein: 32.5%) and isolipidic (crude lipid: 9.22%) diets were formulated containing DL-α-tocopheryl acetate at concentrations of 0, 40, 80, 120 and 160 mg/kg (E13.1, E50.6, E90.5, E130.6 and E163.9, respectively). Post-larval P. vannamei individuals (3.95 ± 0.21 mg) were randomly assigned to 20 tanks and fed the experimental diets for 34 days. After the feeding trial, the shrimp were challenged with ammonia-N for 48 h to evaluate their stress tolerance and immune responses. The shrimp groups fed with diet supplemented with VE exhibited significantly improved growth performance and feed utilization compared to the E13.1 group (P < 0.05). However, dietary VE levels had no significant effect on survival (P > 0.05). Dietary VE supplementation increased LT50 from 36 h in the E13.1 group to 48 h in the E90.5 group. Dietary VE supplementation significantly upregulated the expression of antioxidant-related (SOD, CAT and GPx) and immune-related (Crustin, proPO, HSP70 and Penaeidin-3a) genes both after the feeding trial (0 h) and after ammonia-N exposure (48 h) (P < 0.05). Optimal dietary VE levels estimated using broken-line and second-order polynomial regression analyses ranged from 89.3 to 94.9 mg/kg for growth and 82.6 to 113.9 mg/kg for ammonia-N stress resistance in post-larval P. vannamei. Overall, these findings indicate that dietary VE mitigates acute ammonia-N induced damage in shrimp by enhancing antioxidant defense and immune responses.

Dietary urea levels induce morphological damage of cells, lipid metabolism disorders, and ammonia accumulation in subcutaneous fat in Tibetan sheep

Introduction Urea shows substantial potential as a cost-effective alternative to soybean meal in ruminant production. Given the critical role of subcutaneous adipose tissue (SAT) in meat quality, this study evaluated the effects of different dietary urea levels on the histomorphology, fatty acid composition, lipidomic profiles, and volatile flavour compounds of SAT in Tibetan sheep. Methods Eighty female lambs (16.2 ± 1.01 kg, 2 months old) were randomly assigned to four dietary treatments supplemented with 0% (U0), 0.80% (U1), 1.19% (U2), and 1.61% (U3) urea. The 105-day trial comprised a 15-day adaptation period followed by a 90-day experimental period. Results The results indicated that: high urea levels (U2 and U3) disrupted adipocyte integrity, resulting in disordered arrangement, cellular rupture, and a significant reduction in adipocyte diameter (p < 0.05). Increasing dietary urea levels significantly decreased the concentrations of trans monounsaturated fatty acids (e.g., C16:1 T) and n-3 polyunsaturated fatty acids (p < 0.05), while increasing the level of cis monounsaturated fatty acid C18:1n9c (p < 0.05). Lipidomic analysis identified 48 differential lipid molecules (|log2Fold change| ≥ 2, adjusted p < 0.05), primar ily comprising glycerolipids (Triglycerides, Triglycerides) and glycerophospho lipids (phosphatidylcholine, phosphatidylethanolamine, Phosphatidylglycerol). Urea supplementation significantly influenced the volatile compounds profile (p < 0.05); excessive urea (U3) led to ammonia accumulation and pungent off odors, whereas moderate supplementation imparted desirable milky and vanilla aromas. Discussion In conclusion, dietary urea levels affected lipid metabolism and reduced trans-fatty acid content; excessive dietary urea disrupted cell structure, increased ammonia accumulation and reduced aroma-contributing substances in the SAT of Tibetan sheep.

Hesperidin dietary intervention mitigates ammonia stress-evoked biochemical and metabolic disruption and restores the tlr-5–nf-κβ/mapk gene expression in Oreochromis niloticus

Nigella sativa oil ameliorates malathion-ınduced toxicity in Nile tilapia: a multi-systemic and molecular evaluation

It is demonstrated that dietary Nigella sativa oil effectively mitigates malathion-induced toxic effects and offers a comprehensive insight into the protective mechanisms of black cumin oil in aquaculture.

Dissolved oxygen levels differentially regulate ammonia metabolism plasticity in mandarin fish (Siniperca chuatsi)

Dissolved oxygen (DO) is a key environmental factor affecting fish metabolism, yet its regulatory role in ammonia production, conversion, and excretion remains poorly understood. This study investigated how DO levels modulate ammonia metabolism plasticity in mandarin fish (Siniperca chuatsi) as a potential biological strategy for mitigating aquaculture-derived ammonia pollution. Fish were exposed to normoxia (6.05 ± 0.17 mg/L), hypoxia (2.67 ± 0.25 mg/L), or hyperoxia (9.73 ± 0.62 mg/L) for 48 h. Results showed that hypoxia caused oxidative stress, as evidenced by elevated MDA levels, suppressed SOD and CAT activities, and obvious tissue damage to the livers and gills of S. chuatsi. In response to this stress, both hypoxia and hyperoxia enhanced the antioxidant capacity of S. chuatsi via the Nrf2/Keap1 pathway. Compared to the normoxia and hyperoxia groups, the ammonia excretion rate was significantly lower in the hypoxia group. Distinct adaptive strategies in ammonia homeostasis were observed under different DO conditions. Under hypoxic condition, S. chuatsi downregulated hepatic glutamate dehydrogenase (gdh) to reduce ammonia production, upregulated carbamyl phosphate synthase 1 (cps1) to promote ammonia conversion to urea, and upregulated RH glycoproteins and Na+/H+ exchanger 3 (nhe3) as a compensatory response, ultimately leading to a 24.06% reduction in water NH4+-N accumulation at 48 h. In contrast, hyperoxia reduced ammonia production and increased urea conversion but did not enhance excretion. Instead, it improved ammonia tolerance in S. chuatsi. In summary, hypoxia reduced net ammonia excretion via integrated adjustments in production, conversion, and excretion, whereas hyperoxia enhanced ammonia tolerance without altering excretion. This DO-mediated metabolic plasticity provides a biological strategy for mitigating aquaculture-derived ammonia pollution by utilizing existing aeration to harness intrinsic fish physiology, supporting the development of sustainable aquaculture.

Dietary Chlorogenic Acid Attenuates Liver Injury, Lipid Metabolic Disturbance, and Inflammatory Responses in Broilers Under High Stocking Density

Simple Summary High stocking density can impair broiler health as live-weight load per unit area increases during growth. This study examined whether 0.1% dietary chlorogenic acid (CGA), supplied from 7 to 42 d of age, could support liver health in broilers housed at 14 or 22 birds/m2. At 42 d, the recorded live-weight densities were 35.00 and 34.48 kg/m2 in the normal-density groups without and with CGA, respectively, and 50.25 and 49.38 kg/m2 in the corresponding high-density groups. Compared with their corresponding normal-density groups, the high-density groups had lower body weights and later-stage average daily gains, whereas CGA did not significantly restore growth within either stocking density. Compared with the HD group, the HDCGA group was associated with improved hepatic antioxidant indices and less severe lipid deposition and inflammatory changes in representative liver sections. The molecular findings showed treatment-associated differences in NOX5, SREBP1, ACACA, PLA2G4A, COX-2, ALOX5, and AMPK mRNA abundance. Thus, 0.1% CGA may support hepatic health under high-density conditions, although growth recovery was not demonstrated and only one CGA dose was evaluated.