Abstract
The negative impacts of high stocking density on the commercial poultry industry compromise sustainable birds' productivity and welfare. Thus, we investigated the potential of colocynth seed (CC) supplementation in alleviating the negative impacts of high stocking density on broilers' performance, immunity, inflammation, and redox status. A total of 648 one-day-old male Cobb 500 chicks were recruited and distributed into 2 x 2 factorial arrangements. The treatment groups were assigned based on stocking density as low stocking density (9 birds/m(2); LSD) or high stocking density (19 birds/m(2); HSD), and CC supplementation as without (0 g/kg feed; -CC) or with (1 g/kg feed; +CC) supplementation. Data were collected from week three to week five of age. Production performance was monitored and meat quality was assessed. Blood samples were collected to measure stress markers, humoral immune response, inflammatory cytokines, and antioxidant activity levels. The results indicated that HSD induced production performance reduction, immunosuppression, and imbalance redox status, along with elevation in inflammation and stress markers levels. Breast meat weight and yield were reduced in the HSD groups by 9 and 1%, respectively, compared to LSD groups. However, CC supplementation to HSD birds was able to slightly improve daily weight gain, body weight gain, and breast weight, showing no significant difference compared to the LSD-CC group, and significantly increased breast yield. Furthermore, CC supplementation significantly reduced inflammatory cytokines and stress markers levels. Under HSD, both cell-mediated and humeral immune responses were elevated with CC supplementation compared with the non-supplemented group. It can be concluded that HSD is a detrimental factor in the commercial poultry industry, which generates oxidative and inflammatory responses and, subsequently, immunosuppression and impaired performance. Nevertheless, dietary CC supplementation can be used as a natural antioxidant source to mitigate the negative impacts of HSD on broilers' production performance, as well as physiological competency.