Effects of Diets with Varying Astaxanthin from Yarrowia lipolytica Levels on the Growth, Feed Utilization, Metabolic Enzymes Activities, Antioxidative Status and Serum Biochemical Parameters of Litopenaeus vannamei

Abstract

Litopenaeus vannamei was divided into seven groups (defined as diets A0–A6) and fed with diets respectively containing 0, 0.5, 1, 2, 4 and 8 g/kg Yarrowia lipolytica (astaxanthin content: 1.5%) and 3 g/kg Haematococcus pluvialis (astaxanthin content: 2%). After an eight-week feeding trial, the results reflected that different levels of Y. lipolytica and H. pluvialis could significantly increase the weight gain rate of L. vannamei (p < 0.05). The condition factor and weight gain rate of group A4 were significantly higher than those of the other groups (p < 0.05); the HSI significantly decreased with the increase of Y. lipolytica (p < 0.05). The addition of Y. lipolytica to the diet had significant effects on total protein (TP), albumin (ALB), glutathione peroxidase (GSH-Px), malonaldehyde (MDA) and total antioxidant capacity (T-AOC) (p < 0.05). The total protein and albumin of the A5 and A6 groups were significantly higher than those of the other groups (p < 0.05). The GSH-Px activity of the A5 group was the highest and the T-AOC of the A0 group was the lowest. Inducible nitric oxide synthase (I-NOS) increased with the addition of Y. lipolytica (p < 0.05). Y. lipolytica inclusion had no negative effect on physiological and biochemical parameters and some serum immune and antioxidant indexes (p > 0.05). Astaxanthin in Y. lipolytica had an obvious effect on body color. After cooking, the body color of the shrimp deepened with increasing Y. lipolytica content. The red body color of L. vannamei was significantly improved by adding yeasts hydrolysate 2~8 g/kg to the diet. According to the regression analysis between the level of Y. lipolytica added to the diets and the weight gain rates, the optimal level of Y. lipolytica is 4.64 g/kg.