Selenium is an essential micronutrient that plays a key role in mitigating oxidative stress, an escalating challenge in intensive shrimp farming. Selenium’s biological effectiveness is highly dependent on the form in which it is delivered. This study aimed to evaluate how hydroxy-selenomethionine (OH-SeMet), compared to sodium selenite (SS) and selenium yeast (Se-Yeast), enhances stress resistance by improving the shrimp’s antioxidant status, and how this benefit translates into better performance and final product quality.
The trial was conducted on whiteleg shrimp (Penaeus vannamei, 0.15 g), which were fed diets supplemented with three different selenium sources, sodium selenite (SS), selenium yeast (Se-Yeast), or OH-SeMet (Selisseo®, Adisseo), each at 0.3 mg/kg. After a 127-day grow-out period, the shrimp were subjected to an acute nitrite toxicity challenge at an acute lethal dose resulting in 100% mortality within 8 hours. Key assessments included selenium deposition in tissues, antioxidant defense activity (GSH, T-AOC), growth performance, flesh quality parameters such as fillet yield and cooking loss after frozen storage and survival under stress challenge.
Supplementation with OH-SeMet significantly improved shrimp resistance to physiological stress. After a 4-hour nitrite challenge, survival in the OH-SeMet 0.3 mg/kg group remained at 70% compared to 0% in the SS group, and 50% in the Se-Yeast group (P<0.001). This resilience was linked to enhanced antioxidant defenses, as evidenced by significantly higher levels of total antioxidant capacity (GSH, T-AOC), attributed to the greater bioavailability of OH-SeMet. Selenium deposition in tissues was 23% higher than in the SS group (2.538 vs. 2.056 µg/g, P<0.001), and 6.5% higher than in the Se-Yeast group (2.538 vs. 2.383 µg/g, P<0.001). This improved physiological status translated into better growth performance. Shrimp fed OH-SeMet reached a higher final body weight (11.6 g vs. 10.4 g for SS and 10.9 g for Se-Yeast, P<0.001), higher survival (83% vs. 67% for SS and 75% for Se-Yeast, P<0.001), and a more efficient FCR (1.8 vs. 2.3 for SS and 2.0 for Se-Yeast, P<0.001) after the 127-day grow-out period. The antioxidant benefits of OH-SeMet extended beyond stress resistance to meat quality. Shrimp from the OH-SeMet group yielded the highest fillet percentage (50%, P<0.001) and the lowest cooking loss (28%, P=0.0354) after 60 days of frozen storage. In conclusion, OH-SeMet enhances shrimp health and productivity through a well-defined mechanism: improved selenium deposition boosts antioxidant capacity, which in turn strengthens stress resistance, growth performance, and meat quality.