Vitamin A with L-ascorbic acid sodium salt improves the growth performance, immune function and antioxidant capacity of weaned pigs.

Vitamin A is easily degraded by environmental factors. Therefore, it is very important to add antioxidants during Vitamin A production. In the past, ethoxyquin (EQ) was widely used, but recent studies have found that it has potential toxicity. Therefore, in this study, we evaluated the antioxidant activities of 4 antioxidants in vitro: EQ, butylated hydroxytoluene, α-tocopherol and L-ascorbic acid sodium salt (Vitamin C sodium). In vitro experiments showed that Vitamin C sodium had better antioxidant capacity. Then, we explored the effects of different antioxidant types of Vitamin A on the growth performance, immune function and antioxidant capacity of weaned pigs. In total, 288 weaned piglets with an initial mean BW of 8.34 ± 0.02 kg at 30 days old were randomly divided into three groups with four replicates and 24 piglets per replicate for 35 days of feeding. The experimental diets were as follows: i) basal diet without external Vitamin A (NC); ii) basal diet supplemented with 12000 IU/kg EQ Vitamin A and iii) basal diet supplemented with 12000 IU/kg Vitamin C sodium Vitamin A. On day 36, two pigs from each replicate were selected to collect serum samples. The in vivo results showed that pigs in the EQ Vitamin A and Vitamin C sodium Vitamin A groups had significantly higher final weight and average daily gain (P < 0.05). During the trial, the levels of IgG and glutathione peroxidase in the EQ Vitamin A and Vitamin C sodium Vitamin A groups were significantly higher than those in the NC group (P < 0.05), and the malondialdehyde content was significantly lower (P < 0.05). On the 36th day, the levels of IgA and total antioxidant capacity in the Vitamin C sodium Vitamin A group were significantly higher than those in the EQ Vitamin A and NC (P < 0.05) groups. Thus, Vitamin C sodium Vitamin A can significantly improve the growth performance, antioxidant capacity and immune function of weaned pigs. Meanwhile, Vitamin C sodium may replace EQ as an antioxidant additive for Vitamin A.