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Monthly variations in reproductive indices, egg quality, and larval survival of broodstock snubnose pompano (<em>Trachinotus blochii</em>)
Full text linkThis study evaluated the monthly variations in reproductive indices, egg quality, and larval survival of broodstock snubnose pompano (Trachinotus blochii) reared under captivity conditions from January to December. The parameters assessed included gonadal maturation rate, fecundity, egg diameter, egg buoyancy rate, fatty acid composition (SFA, MUFA, PUFA, and HUFA) in egg, fertilization rate, hatching rate, and 3-day larval survival rate. The results showed that May, July, November, and December were the most favorable periods regarding reproductive performance and egg quality, with maturation rates exceeding 70% and hatching rates surpassing 90%. Notably, July recorded the highest fecundity (107,454 eggs/kg female), and larval survival peaked at nearly 60% during this month. These findings highlight the significant influence of time and environmental factors on reproductive success and seed quality. Analyses revealed a strong relationship between egg quality and larval survival, with the nutrient content of eggs, particularly long-chain polyunsaturated fatty acids such as DHA and EPA. Therefore, the study recommends proactively developing seasonally aligned spawning schedules and providing targeted nutritional supplementation to broodstock during maturation to enhance sustainable seed production efficiency for this high-value marine species
Effects of neuroendocrine on the immune and metabolic functions of <em>Litopenaeus vannamei</em> under high nitrite conditions
Full text linkIn recent years, nitrite toxicity has become a significant concern in shrimp aquaculture, affecting cultured species' health and productivity. Herein, we investigated the impacts of nitrite on the immune and metabolic functions of Litopenaeus vannamei and assessed the impacts of eyestalk hormone on these parameters when shrimp were cultured under high nitrite conditions. After exposure of L. vannamei to nitrite-N at 0, 2.5, 5, 7.5, 10 mg/L, and unilateral eyestalk-ablated shrimp only to nitrite-N at 10 mg/L for 48 h, phenoloxidase (PO) activity, antibacterial activity, bacteriolytic activity, oxyhemocyanin, lactate, and glucose contents were measured. Oxyhemocyanin levels decreased as the nitrite-N concentrations increased, while lactate and glucose levels increased. This indicated that conversion from aerobic to anaerobic respiratory metabolism is exacerbated by hypoxia-induced nitrite stress to ensure that readily metabolizable energy stores are available to meet increased energy demand. The decrease in PO levels, antibacterial activity, and bacteriolytic activity in the hemolymph indicated that the physiological and immunological responses of L. vannamei was impaired by subjection to nitrite-N. Under the same nitrite-N conditions, eyestalk ablation caused a remarkable decrease in glucose, lactate, and PO levels, compared with those detected in the non-ablated eyestalk group. These findings suggest that the eyestalk hormone in L. vannamei increases metabolic and immune responses as a protective mechanism against nitrite-N stress
Papers from the 33rd Conference of the Southeast Asian Linguistics Society (2024)
No full textThis volume contains 19 articles from SEALS 33 (the 33rd Annual Meeting of the Southeast Asian Linguistics Society)
Political Offices: U.S. House of Representatives: Federal Departments & Agencies: Dept. of Defense: Land - Sand Island
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