Effects of dietary octacosanol supplementation on growth, feed utilization, and physiological and molecular responses of red claw crayfish (Cherax quadricarinatus)

Crayfish species like Cherax quadricarinatus are crucial nutrients that contribute to the world economy but face challenges in production due to dietary supplements. Octacosanol offers diverse health benefits, from immunity boosts to anti-inflammatory and anti-tumor effects. The current investigation assessed the ovarian changes, immune reaction, availability of antioxidants, gene response pattern, and entire organ performance of the red claw crayfish after supplementation with different levels of octacosanol. Two hundred twenty-five C. quadricarinatus with an initial weight of 53 ± 1.11 (g/crayfish) were randomly stocked into fiberglass tanks (15 crayfish/tank) and fed each day with three diverse dietary octacosanols. Different levels of octacosanol (4, 8, 12, and 16 mg/kg) were tested in triplicates over 60 days, denoted as D1, D2, D3, and D4, respectively, excluding the control group. The study revealed that 8 mg/kg octacosanol effectively enhances growth and feed utilization in C. quadricarinatus , while also improving ovarian performance by increasing hepatosomatic index (HSI), gonadosomatic index (GSI), and condition factor (CF). Additionally, it decreased levels of MDA and NO in crayfish. Supplementation with 16 mg/kg octacosanol boosted antioxidant capacity by enhancing activities of T-AOC and SOD, as well as influencing nonspecific immune enzymes in the hepatopancreas at doses of D3 (12 mg/kg) and D4 (16 mg/kg). Furthermore, it positively impacted GLU and protein profiles while reducing levels of T-BIL, T-CHOL, TG, LDL-c, and VLDL-c in crayfish. These dietary interventions also regulated gene expression associated with reproduction, lipid metabolism, antioxidants, and immune response in various organs of C. quadricarinatus . Octacosanol demonstrated potential as a safe and effective feed additive. According to quadratic regression analysis, nutritional supplementation of octacosanol at 9 mg/kg diet is considered the recommended dosage in the red claw crayfish diet.