Sweet Orange (Citrus sinensis) Peel Powder with Xylanase Supplementation Improved Growth Performance, Antioxidant Status, and Immunity of Broiler Chickens

Abstract

The global population is estimated to reach approximately 9.7 billion persons by 2050. To meet the demands of the growing population, highly valuable feedstuffs that have traditionally been included as staples in poultry diets (e.g., corn and soybeans) are being reallocated for human nutrition purposes. As the availability of conventional poultry feedstuffs has decreased, poultry nutritionists are investigating the potential use of nonconventional feedstuffs in poultry diets. The objective of this study was to investigate the effects of utilizing dried sweet orange (Citrus Sinensis) peel powder (with and without xylanase supplementation) as a nonconventional feedstuff on production and health parameters in broiler chickens. A total of 375-day-old male Cobb 500 chicks were weighed and blocked for their initial body weight and randomly assigned to 25 pens (15 birds/pen). Dietary treatments were randomly and independently applied to each pen (5 replicates/per treatment). The following five dietary treatments were investigated in this study: 1) CON: basal corn-soya diet, 2) OPP3: basal diet containing 3% orange peel powder, 3) OPP5: basal diet containing 5% orange peel powder, 4) OPP3ENZ: OPP3 diet with xylanase enzyme added (50g/metric ton) and 5) OPP5ENZ: OPP5 diet with xylanase enzyme added (50g/metric ton). Feed intake and body weight were recorded on a weekly basis. Blood samples were collected at the end of the trial and analyzed for antioxidant and immune-related metabolites. The weights of internal organs (including immunological organs) were collected and reported. The data were statistically analyzed using PROC MIXED in SAS (SAS 9.4). Regardless of xylanase supplementation, the OPP-fed birds had decreased feed intakes and improved feed efficiency than the birds that received the control treatment (P=0.01). Significantly reduced Malondialdehyde (MDA) levels in the blood in all OPP-fed groups (P=0.01) compared to the CON group, but relative thymus weight was increased in the OPP5ENZ group. In conclusion, the inclusion of OPP in the broiler chicken diet (up to 5% of DMI) with xylanase enzyme supplementation could improve antioxidant capacity and cellular immune responses, positively impacting production.