Effect of Green Tea (Camellia sinensis) Extract on Growth Performance, Intestinal Health, and Immune Response of Broiler Chickens During Subclinical Necrotic Enteritis

This study evaluated the effects of varying levels of dietary green tea extract (GTE) on growth performance, Clostridium perfringens (CP) colonization, and inflammatory responses in broiler chickens during experimental subclinical necrotic enteritis (SNE). In a 21-day experiment, 480 one-day-old male broiler (Ross 708) chicks were equally allotted into four dietary treatment groups. From days 1 to 10, all groups received a corn–soy basal diet, switching to a wheat-fish diet on day 11. Treatments included CON (no GTE), GTX, GTY, and GTZ (250, 500, and 1000 mg/kg GTE, respectively). On day 11, each group split into ACON, AGTX, AGTY, and AGTZ, totaling eight treatments. From days 17 to 20, ACON, AGTX, AGTY, and AGTZ chicks were orally challenged twice daily with 3 mL CP26 (2.5 × 10⁸ CFU/mL). On d 16 (pre-challenge) and d 1 post-challenge, ileo-jejunal contents were collected for CP enumeration, and jejunum tissue was analyzed via qRT-PCR to determine the expression levels of IL-1β, IFNγ, TNF-α, TGFβ, IL-10, and MUC2 genes. Challenged chicks showed poorer (p ≤ 0.05) growth and higher intestinal CP, with a potential improvement in GTE-supplemented diets. Findings suggests that dietary GTE supplementation mitigated the characteristic growth depression during SNE, reduced intestinal CP infection, and modulated inflammatory response in broiler chicks.