Effects of Supplemental Bromelain on Egg Production and Quality, Serum and Liver Traits of Laying Hens

This study evaluated the effects of bromelain supplementation on the egg production and quality, and serum and liver traits in laying hens. Sixty 75-week-old white Leghorn hens were used in this study, birds were randomly assigned to a control (basal diet), low-dose bromelain supplemental group (0.14g/kg feed; 250 U/kg feed) and high-dose bromelain supplemental group (0.28g/kg feed; 500 U/kg feed). Study period was 45 days. Experimental results indicated that bromelain supplementation no effects on feed intake, egg production, egg weight, feed/egg and yolk cholesterol (P > 0.05). Eggshell thickness increased in the high-dose bromelain group (P < 0.05). Liver cholesterol levels were dose-dependently and significantly reduced in both bromelain supplementation groups (P < 0.05); Serum cholesterol levels were reduced in the high-dose bromelain group (P < 0.05). Liver glutamate pyruvate transaminase (GPT) activity in the high-dose bromelain group was markedly lower than that in the control group (P < 0.05). Serum total protein, total globulin and IgG levels in both bromelain supplementation groups were significantly increased compared with those in the control group (P < 0.05). Percentage concentration of high-density lipoprotein (HDL) was enhanced in both bromelain supplementation groups, whereas, very low-density+low-density lipoprotein (VLDL+LDL) percentage was decreased compared with that in the control group (P < 0.05). This study indicated that bromelain supplemented to diet of old laying hens displayed beneficial to maintain bird health.