Effect of L-Carnitine and/or Calf Thymus Gland Extract Supplementation on Immunity, Antioxidant, Duodenal Histomorphometric, Growth, and Economic Performance of Japanese Quail (Coturnix coturnix japonica)

This study aimed to evaluate the supplementation (of drinking water) effects of L-Carnitine (LC) and/or calf thymus extract (TE) on immunity, antioxidant, duodenal histomorphometric, growth, and economic performance of Japanese quail. Six hundred, one day old unsexed quail were divided into four groups, the control group (G1) received plain drinking water, while G2, G3, and G4 were supplemented with LC and/or TE, respectively. The treated groups recorded a significant (p < 0.05) improvement in the final body weight, weight gain, feed conversion ratio, phagocytic activity %, phagocytic index, lymphocytes %, and plasma glutathione level compared to the G1. On the other hand, these supplementations significantly lower the mortality rate %, heterophil %, H/L ratio and plasma malondialdehyde level of the supplemented groups relative to G1. The supplemented groups recorded a non-significant increase in duodenal histomorphometric parameters (villous height, villous width, surface area, and crypt depth) relative to G1. Generally, LC and/or TE improve the values of economic profile (total returns, net profit, total return/total costs %, etc.) in treated groups compared to the control one. In conclusion, L-carnitine supplementation was more effective than TE or their combination with TE in the immunological, anti-oxidative, growth, and economic performance.