Impact of Chlorella vulgaris as feed ingredient and carbohydrases on the health status and hepatic lipid metabolism of finishing pigs

The implication of high dietary level of Chlorella vulgaris, individually and supplemented with two carbohydrase mixtures, on pigs' health and liver metabolism was assessed in this study. Forty crossbred (Large White x Landrace sows crossed with Pietrain boars) entire male pigs were randomly allocated to the following feeding treatments (n = 10): cereal-soybean meal basal diet (control); basal diet with 5% C. vulgaris; basal diet with 5% C. vulgaris supplemented with 0.005% Rovabio (R) Excel AP; and basal diet with 5% C. vulgaris supplemented with 0.01% of a preselected four-CAZyme mixture. The trial lasted from 59.1 +/-& nbsp;5.69 kg of initial live weight to 101 & nbsp;+/- 1.9 kg of slaughter weight. Data indicate that this high dietary level of C. vulgaris has impact on several blood parameters of finishing pigs. However, the most relevant health outcome observed was a strong immunosuppressive effect promoted by the microalga, which increases pigs' susceptibility to infection diseases. In addition, the dietary incorporation of C. vulgaris reduced the systemic antioxidant capacity of pigs. In turn, the dietary supplementation with the four-CAZyme mixture promoted a clear decrease on some blood parameters compared with the control group. Regarding hepatic lipids, pigs fed C. vulgaris diets, had an increased hepatic content of n-3 PUFA, with a consequent decrease on the n-6/n-3 ratio. In conclusion, the use of C. vulgaris as feed ingredient appears to be safe under controlled experimental conditions. However, it is imperative test it in industrial production systems, with more stressful and less hygienic environments.

Automated summary

This study assessed the impact of a high dietary level of Chlorella vulgaris with and without carbohydrase mixtures on the health and liver metabolism of pigs. The results showed that the dietary level of C. vulgaris affected several blood parameters of finishing pigs and increased their susceptibility to infection diseases. The dietary supplementation with carbohydrase mixtures decreased some blood parameters. Additionally, feeding C. vulgaris increased the hepatic content of n-3 polyunsaturated fatty acids in pigs.